// SPDX-License-Identifier: GPL-2.0
/*
 * Infrastructure for profiling code inserted by 'gcc -pg'.
 *
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
 *
 * Originally ported from the -rt patch by:
 *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
 *
 * Based on code in the latency_tracer, that is:
 *
 *  Copyright (C) 2004-2006 Ingo Molnar
 *  Copyright (C) 2004 Nadia Yvette Chambers
 */

#include <linux/stop_machine.h>
#include <linux/clocksource.h>
#include <linux/sched/task.h>
#include <linux/kallsyms.h>
#include <linux/security.h>
#include <linux/seq_file.h>
#include <linux/tracefs.h>
#include <linux/hardirq.h>
#include <linux/kthread.h>
#include <linux/uaccess.h>
#include <linux/bsearch.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/sort.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/rcupdate.h>
#include <linux/kprobes.h>

#include <trace/events/sched.h>

#include <asm/sections.h>
#include <asm/setup.h>

#include "ftrace_internal.h"
#include "trace_output.h"
#include "trace_stat.h"

#define FTRACE_WARN_ON(cond)                    \
        ({                                      \
                int ___r = cond;                \
                if (WARN_ON(___r))              \
                        ftrace_kill();          \
                ___r;                           \
        })

#define FTRACE_WARN_ON_ONCE(cond)               \
        ({                                      \
                int ___r = cond;                \
                if (WARN_ON_ONCE(___r))         \
                        ftrace_kill();          \
                ___r;                           \
        })

/* hash bits for specific function selection */
#define FTRACE_HASH_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12

#ifdef CONFIG_DYNAMIC_FTRACE
#define INIT_OPS_HASH(opsname)  \
        .func_hash              = &opsname.local_hash,                  \
        .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
#else
#define INIT_OPS_HASH(opsname)
#endif

enum {
        FTRACE_MODIFY_ENABLE_FL         = (1 << 0),
        FTRACE_MODIFY_MAY_SLEEP_FL      = (1 << 1),
};

struct ftrace_ops ftrace_list_end __read_mostly = {
        .func           = ftrace_stub,
        .flags          = FTRACE_OPS_FL_STUB,
        INIT_OPS_HASH(ftrace_list_end)
};

/* ftrace_enabled is a method to turn ftrace on or off */
int ftrace_enabled __read_mostly;
static int last_ftrace_enabled;

/* Current function tracing op */
struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
/* What to set function_trace_op to */
static struct ftrace_ops *set_function_trace_op;

static bool ftrace_pids_enabled(struct ftrace_ops *ops)
{
        struct trace_array *tr;

        if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
                return false;

        tr = ops->private;

        return tr->function_pids != NULL || tr->function_no_pids != NULL;
}

static void ftrace_update_trampoline(struct ftrace_ops *ops);

/*
 * ftrace_disabled is set when an anomaly is discovered.
 * ftrace_disabled is much stronger than ftrace_enabled.
 */
static int ftrace_disabled __read_mostly;

DEFINE_MUTEX(ftrace_lock);

struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
struct ftrace_ops global_ops;

#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
                                 struct ftrace_ops *op, struct ftrace_regs *fregs);
#else
/* See comment below, where ftrace_ops_list_func is defined */
static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
#endif

static inline void ftrace_ops_init(struct ftrace_ops *ops)
{
#ifdef CONFIG_DYNAMIC_FTRACE
        if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
                mutex_init(&ops->local_hash.regex_lock);
                ops->func_hash = &ops->local_hash;
                ops->flags |= FTRACE_OPS_FL_INITIALIZED;
        }
#endif
}

static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
                            struct ftrace_ops *op, struct ftrace_regs *fregs)
{
        struct trace_array *tr = op->private;
        int pid;

        if (tr) {
                pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
                if (pid == FTRACE_PID_IGNORE)
                        return;
                if (pid != FTRACE_PID_TRACE &&
                    pid != current->pid)
                        return;
        }

        op->saved_func(ip, parent_ip, op, fregs);
}

static void ftrace_sync_ipi(void *data)
{
        /* Probably not needed, but do it anyway */
        smp_rmb();
}

static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
{
        /*
         * If this is a dynamic, RCU, or per CPU ops, or we force list func,
         * then it needs to call the list anyway.
         */
        if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
            FTRACE_FORCE_LIST_FUNC)
                return ftrace_ops_list_func;

        return ftrace_ops_get_func(ops);
}

static void update_ftrace_function(void)
{
        ftrace_func_t func;

        /*
         * Prepare the ftrace_ops that the arch callback will use.
         * If there's only one ftrace_ops registered, the ftrace_ops_list
         * will point to the ops we want.
         */
        set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
                                                lockdep_is_held(&ftrace_lock));

        /* If there's no ftrace_ops registered, just call the stub function */
        if (set_function_trace_op == &ftrace_list_end) {
                func = ftrace_stub;

        /*
         * If we are at the end of the list and this ops is
         * recursion safe and not dynamic and the arch supports passing ops,
         * then have the mcount trampoline call the function directly.
         */
        } else if (rcu_dereference_protected(ftrace_ops_list->next,
                        lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                func = ftrace_ops_get_list_func(ftrace_ops_list);

        } else {
                /* Just use the default ftrace_ops */
                set_function_trace_op = &ftrace_list_end;
                func = ftrace_ops_list_func;
        }

        update_function_graph_func();

        /* If there's no change, then do nothing more here */
        if (ftrace_trace_function == func)
                return;

        /*
         * If we are using the list function, it doesn't care
         * about the function_trace_ops.
         */
        if (func == ftrace_ops_list_func) {
                ftrace_trace_function = func;
                /*
                 * Don't even bother setting function_trace_ops,
                 * it would be racy to do so anyway.
                 */
                return;
        }

#ifndef CONFIG_DYNAMIC_FTRACE
        /*
         * For static tracing, we need to be a bit more careful.
         * The function change takes affect immediately. Thus,
         * we need to coordinate the setting of the function_trace_ops
         * with the setting of the ftrace_trace_function.
         *
         * Set the function to the list ops, which will call the
         * function we want, albeit indirectly, but it handles the
         * ftrace_ops and doesn't depend on function_trace_op.
         */
        ftrace_trace_function = ftrace_ops_list_func;
        /*
         * Make sure all CPUs see this. Yes this is slow, but static
         * tracing is slow and nasty to have enabled.
         */
        synchronize_rcu_tasks_rude();
        /* Now all cpus are using the list ops. */
        function_trace_op = set_function_trace_op;
        /* Make sure the function_trace_op is visible on all CPUs */
        smp_wmb();
        /* Nasty way to force a rmb on all cpus */
        smp_call_function(ftrace_sync_ipi, NULL, 1);
        /* OK, we are all set to update the ftrace_trace_function now! */
#endif /* !CONFIG_DYNAMIC_FTRACE */

        ftrace_trace_function = func;
}

static void add_ftrace_ops(struct ftrace_ops __rcu **list,
                           struct ftrace_ops *ops)
{
        rcu_assign_pointer(ops->next, *list);

        /*
         * We are entering ops into the list but another
         * CPU might be walking that list. We need to make sure
         * the ops->next pointer is valid before another CPU sees
         * the ops pointer included into the list.
         */
        rcu_assign_pointer(*list, ops);
}

static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
                             struct ftrace_ops *ops)
{
        struct ftrace_ops **p;

        /*
         * If we are removing the last function, then simply point
         * to the ftrace_stub.
         */
        if (rcu_dereference_protected(*list,
                        lockdep_is_held(&ftrace_lock)) == ops &&
            rcu_dereference_protected(ops->next,
                        lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                *list = &ftrace_list_end;
                return 0;
        }

        for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
                if (*p == ops)
                        break;

        if (*p != ops)
                return -1;

        *p = (*p)->next;
        return 0;
}

static void ftrace_update_trampoline(struct ftrace_ops *ops);

int __register_ftrace_function(struct ftrace_ops *ops)
{
        if (ops->flags & FTRACE_OPS_FL_DELETED)
                return -EINVAL;

        if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
                return -EBUSY;

#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
        /*
         * If the ftrace_ops specifies SAVE_REGS, then it only can be used
         * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
         * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
         */
        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
            !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
                return -EINVAL;

        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
                ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
#endif
        if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
                return -EBUSY;

        if (!core_kernel_data((unsigned long)ops))
                ops->flags |= FTRACE_OPS_FL_DYNAMIC;

        add_ftrace_ops(&ftrace_ops_list, ops);

        /* Always save the function, and reset at unregistering */
        ops->saved_func = ops->func;

        if (ftrace_pids_enabled(ops))
                ops->func = ftrace_pid_func;

        ftrace_update_trampoline(ops);

        if (ftrace_enabled)
                update_ftrace_function();

        return 0;
}

int __unregister_ftrace_function(struct ftrace_ops *ops)
{
        int ret;

        if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
                return -EBUSY;

        ret = remove_ftrace_ops(&ftrace_ops_list, ops);

        if (ret < 0)
                return ret;

        if (ftrace_enabled)
                update_ftrace_function();

        ops->func = ops->saved_func;

        return 0;
}

static void ftrace_update_pid_func(void)
{
        struct ftrace_ops *op;

        /* Only do something if we are tracing something */
        if (ftrace_trace_function == ftrace_stub)
                return;

        do_for_each_ftrace_op(op, ftrace_ops_list) {
                if (op->flags & FTRACE_OPS_FL_PID) {
                        op->func = ftrace_pids_enabled(op) ?
                                ftrace_pid_func : op->saved_func;
                        ftrace_update_trampoline(op);
                }
        } while_for_each_ftrace_op(op);

        update_ftrace_function();
}

#ifdef CONFIG_FUNCTION_PROFILER
struct ftrace_profile {
        struct hlist_node               node;
        unsigned long                   ip;
        unsigned long                   counter;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        unsigned long long              time;
        unsigned long long              time_squared;
#endif
};

struct ftrace_profile_page {
        struct ftrace_profile_page      *next;
        unsigned long                   index;
        struct ftrace_profile           records[];
};

struct ftrace_profile_stat {
        atomic_t                        disabled;
        struct hlist_head               *hash;
        struct ftrace_profile_page      *pages;
        struct ftrace_profile_page      *start;
        struct tracer_stat              stat;
};

#define PROFILE_RECORDS_SIZE                                            \
        (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))

#define PROFILES_PER_PAGE                                       \
        (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))

static int ftrace_profile_enabled __read_mostly;

/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
static DEFINE_MUTEX(ftrace_profile_lock);

static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);

#define FTRACE_PROFILE_HASH_BITS 10
#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)

static void *
function_stat_next(void *v, int idx)
{
        struct ftrace_profile *rec = v;
        struct ftrace_profile_page *pg;

        pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);

 again:
        if (idx != 0)
                rec++;

        if ((void *)rec >= (void *)&pg->records[pg->index]) {
                pg = pg->next;
                if (!pg)
                        return NULL;
                rec = &pg->records[0];
                if (!rec->counter)
                        goto again;
        }

        return rec;
}

static void *function_stat_start(struct tracer_stat *trace)
{
        struct ftrace_profile_stat *stat =
                container_of(trace, struct ftrace_profile_stat, stat);

        if (!stat || !stat->start)
                return NULL;

        return function_stat_next(&stat->start->records[0], 0);
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* function graph compares on total time */
static int function_stat_cmp(const void *p1, const void *p2)
{
        const struct ftrace_profile *a = p1;
        const struct ftrace_profile *b = p2;

        if (a->time < b->time)
                return -1;
        if (a->time > b->time)
                return 1;
        else
                return 0;
}
#else
/* not function graph compares against hits */
static int function_stat_cmp(const void *p1, const void *p2)
{
        const struct ftrace_profile *a = p1;
        const struct ftrace_profile *b = p2;

        if (a->counter < b->counter)
                return -1;
        if (a->counter > b->counter)
                return 1;
        else
                return 0;
}
#endif

static int function_stat_headers(struct seq_file *m)
{
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        seq_puts(m, "  Function                               "
                 "Hit    Time            Avg             s^2\n"
                    "  --------                               "
                 "---    ----            ---             ---\n");
#else
        seq_puts(m, "  Function                               Hit\n"
                    "  --------                               ---\n");
#endif
        return 0;
}

static int function_stat_show(struct seq_file *m, void *v)
{
        struct ftrace_profile *rec = v;
        char str[KSYM_SYMBOL_LEN];
        int ret = 0;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        static struct trace_seq s;
        unsigned long long avg;
        unsigned long long stddev;
#endif
        mutex_lock(&ftrace_profile_lock);

        /* we raced with function_profile_reset() */
        if (unlikely(rec->counter == 0)) {
                ret = -EBUSY;
                goto out;
        }

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        avg = div64_ul(rec->time, rec->counter);
        if (tracing_thresh && (avg < tracing_thresh))
                goto out;
#endif

        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
        seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        seq_puts(m, "    ");

        /* Sample standard deviation (s^2) */
        if (rec->counter <= 1)
                stddev = 0;
        else {
                /*
                 * Apply Welford's method:
                 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
                 */
                stddev = rec->counter * rec->time_squared -
                         rec->time * rec->time;

                /*
                 * Divide only 1000 for ns^2 -> us^2 conversion.
                 * trace_print_graph_duration will divide 1000 again.
                 */
                stddev = div64_ul(stddev,
                                  rec->counter * (rec->counter - 1) * 1000);
        }

        trace_seq_init(&s);
        trace_print_graph_duration(rec->time, &s);
        trace_seq_puts(&s, "    ");
        trace_print_graph_duration(avg, &s);
        trace_seq_puts(&s, "    ");
        trace_print_graph_duration(stddev, &s);
        trace_print_seq(m, &s);
#endif
        seq_putc(m, '\n');
out:
        mutex_unlock(&ftrace_profile_lock);

        return ret;
}

static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
{
        struct ftrace_profile_page *pg;

        pg = stat->pages = stat->start;

        while (pg) {
                memset(pg->records, 0, PROFILE_RECORDS_SIZE);
                pg->index = 0;
                pg = pg->next;
        }

        memset(stat->hash, 0,
               FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
}

int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
{
        struct ftrace_profile_page *pg;
        int functions;
        int pages;
        int i;

        /* If we already allocated, do nothing */
        if (stat->pages)
                return 0;

        stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
        if (!stat->pages)
                return -ENOMEM;

#ifdef CONFIG_DYNAMIC_FTRACE
        functions = ftrace_update_tot_cnt;
#else
        /*
         * We do not know the number of functions that exist because
         * dynamic tracing is what counts them. With past experience
         * we have around 20K functions. That should be more than enough.
         * It is highly unlikely we will execute every function in
         * the kernel.
         */
        functions = 20000;
#endif

        pg = stat->start = stat->pages;

        pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);

        for (i = 1; i < pages; i++) {
                pg->next = (void *)get_zeroed_page(GFP_KERNEL);
                if (!pg->next)
                        goto out_free;
                pg = pg->next;
        }

        return 0;

 out_free:
        pg = stat->start;
        while (pg) {
                unsigned long tmp = (unsigned long)pg;

                pg = pg->next;
                free_page(tmp);
        }

        stat->pages = NULL;
        stat->start = NULL;

        return -ENOMEM;
}

static int ftrace_profile_init_cpu(int cpu)
{
        struct ftrace_profile_stat *stat;
        int size;

        stat = &per_cpu(ftrace_profile_stats, cpu);

        if (stat->hash) {
                /* If the profile is already created, simply reset it */
                ftrace_profile_reset(stat);
                return 0;
        }

        /*
         * We are profiling all functions, but usually only a few thousand
         * functions are hit. We'll make a hash of 1024 items.
         */
        size = FTRACE_PROFILE_HASH_SIZE;

        stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);

        if (!stat->hash)
                return -ENOMEM;

        /* Preallocate the function profiling pages */
        if (ftrace_profile_pages_init(stat) < 0) {
                kfree(stat->hash);
                stat->hash = NULL;
                return -ENOMEM;
        }

        return 0;
}

static int ftrace_profile_init(void)
{
        int cpu;
        int ret = 0;

        for_each_possible_cpu(cpu) {
                ret = ftrace_profile_init_cpu(cpu);
                if (ret)
                        break;
        }

        return ret;
}

/* interrupts must be disabled */
static struct ftrace_profile *
ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
{
        struct ftrace_profile *rec;
        struct hlist_head *hhd;
        unsigned long key;

        key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
        hhd = &stat->hash[key];

        if (hlist_empty(hhd))
                return NULL;

        hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
                if (rec->ip == ip)
                        return rec;
        }

        return NULL;
}

static void ftrace_add_profile(struct ftrace_profile_stat *stat,
                               struct ftrace_profile *rec)
{
        unsigned long key;

        key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
        hlist_add_head_rcu(&rec->node, &stat->hash[key]);
}

/*
 * The memory is already allocated, this simply finds a new record to use.
 */
static struct ftrace_profile *
ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
{
        struct ftrace_profile *rec = NULL;

        /* prevent recursion (from NMIs) */
        if (atomic_inc_return(&stat->disabled) != 1)
                goto out;

        /*
         * Try to find the function again since an NMI
         * could have added it
         */
        rec = ftrace_find_profiled_func(stat, ip);
        if (rec)
                goto out;

        if (stat->pages->index == PROFILES_PER_PAGE) {
                if (!stat->pages->next)
                        goto out;
                stat->pages = stat->pages->next;
        }

        rec = &stat->pages->records[stat->pages->index++];
        rec->ip = ip;
        ftrace_add_profile(stat, rec);

 out:
        atomic_dec(&stat->disabled);

        return rec;
}

static void
function_profile_call(unsigned long ip, unsigned long parent_ip,
                      struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
        struct ftrace_profile_stat *stat;
        struct ftrace_profile *rec;
        unsigned long flags;

        if (!ftrace_profile_enabled)
                return;

        local_irq_save(flags);

        stat = this_cpu_ptr(&ftrace_profile_stats);
        if (!stat->hash || !ftrace_profile_enabled)
                goto out;

        rec = ftrace_find_profiled_func(stat, ip);
        if (!rec) {
                rec = ftrace_profile_alloc(stat, ip);
                if (!rec)
                        goto out;
        }

        rec->counter++;
 out:
        local_irq_restore(flags);
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static bool fgraph_graph_time = true;

void ftrace_graph_graph_time_control(bool enable)
{
        fgraph_graph_time = enable;
}

static int profile_graph_entry(struct ftrace_graph_ent *trace)
{
        struct ftrace_ret_stack *ret_stack;

        function_profile_call(trace->func, 0, NULL, NULL);

        /* If function graph is shutting down, ret_stack can be NULL */
        if (!current->ret_stack)
                return 0;

        ret_stack = ftrace_graph_get_ret_stack(current, 0);
        if (ret_stack)
                ret_stack->subtime = 0;

        return 1;
}

static void profile_graph_return(struct ftrace_graph_ret *trace)
{
        struct ftrace_ret_stack *ret_stack;
        struct ftrace_profile_stat *stat;
        unsigned long long calltime;
        struct ftrace_profile *rec;
        unsigned long flags;

        local_irq_save(flags);
        stat = this_cpu_ptr(&ftrace_profile_stats);
        if (!stat->hash || !ftrace_profile_enabled)
                goto out;

        /* If the calltime was zero'd ignore it */
        if (!trace->calltime)
                goto out;

        calltime = trace->rettime - trace->calltime;

        if (!fgraph_graph_time) {

                /* Append this call time to the parent time to subtract */
                ret_stack = ftrace_graph_get_ret_stack(current, 1);
                if (ret_stack)
                        ret_stack->subtime += calltime;

                ret_stack = ftrace_graph_get_ret_stack(current, 0);
                if (ret_stack && ret_stack->subtime < calltime)
                        calltime -= ret_stack->subtime;
                else
                        calltime = 0;
        }

        rec = ftrace_find_profiled_func(stat, trace->func);
        if (rec) {
                rec->time += calltime;
                rec->time_squared += calltime * calltime;
        }

 out:
        local_irq_restore(flags);
}

static struct fgraph_ops fprofiler_ops = {
        .entryfunc = &profile_graph_entry,
        .retfunc = &profile_graph_return,
};

static int register_ftrace_profiler(void)
{
        return register_ftrace_graph(&fprofiler_ops);
}

static void unregister_ftrace_profiler(void)
{
        unregister_ftrace_graph(&fprofiler_ops);
}
#else
static struct ftrace_ops ftrace_profile_ops __read_mostly = {
        .func           = function_profile_call,
        .flags          = FTRACE_OPS_FL_INITIALIZED,
        INIT_OPS_HASH(ftrace_profile_ops)
};

static int register_ftrace_profiler(void)
{
        return register_ftrace_function(&ftrace_profile_ops);
}

static void unregister_ftrace_profiler(void)
{
        unregister_ftrace_function(&ftrace_profile_ops);
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

static ssize_t
ftrace_profile_write(struct file *filp, const char __user *ubuf,
                     size_t cnt, loff_t *ppos)
{
        unsigned long val;
        int ret;

        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
        if (ret)
                return ret;

        val = !!val;

        mutex_lock(&ftrace_profile_lock);
        if (ftrace_profile_enabled ^ val) {
                if (val) {
                        ret = ftrace_profile_init();
                        if (ret < 0) {
                                cnt = ret;
                                goto out;
                        }

                        ret = register_ftrace_profiler();
                        if (ret < 0) {
                                cnt = ret;
                                goto out;
                        }
                        ftrace_profile_enabled = 1;
                } else {
                        ftrace_profile_enabled = 0;
                        /*
                         * unregister_ftrace_profiler calls stop_machine
                         * so this acts like an synchronize_rcu.
                         */
                        unregister_ftrace_profiler();
                }
        }
 out:
        mutex_unlock(&ftrace_profile_lock);

        *ppos += cnt;

        return cnt;
}

static ssize_t
ftrace_profile_read(struct file *filp, char __user *ubuf,
                     size_t cnt, loff_t *ppos)
{
        char buf[64];           /* big enough to hold a number */
        int r;

        r = sprintf(buf, "%u\n", ftrace_profile_enabled);
        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}

static const struct file_operations ftrace_profile_fops = {
        .open           = tracing_open_generic,
        .read           = ftrace_profile_read,
        .write          = ftrace_profile_write,
        .llseek         = default_llseek,
};

/* used to initialize the real stat files */
static struct tracer_stat function_stats __initdata = {
        .name           = "functions",
        .stat_start     = function_stat_start,
        .stat_next      = function_stat_next,
        .stat_cmp       = function_stat_cmp,
        .stat_headers   = function_stat_headers,
        .stat_show      = function_stat_show
};

static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
{
        struct ftrace_profile_stat *stat;
        struct dentry *entry;
        char *name;
        int ret;
        int cpu;

        for_each_possible_cpu(cpu) {
                stat = &per_cpu(ftrace_profile_stats, cpu);

                name = kasprintf(GFP_KERNEL, "function%d", cpu);
                if (!name) {
                        /*
                         * The files created are permanent, if something happens
                         * we still do not free memory.
                         */
                        WARN(1,
                             "Could not allocate stat file for cpu %d\n",
                             cpu);
                        return;
                }
                stat->stat = function_stats;
                stat->stat.name = name;
                ret = register_stat_tracer(&stat->stat);
                if (ret) {
                        WARN(1,
                             "Could not register function stat for cpu %d\n",
                             cpu);
                        kfree(name);
                        return;
                }
        }

        entry = tracefs_create_file("function_profile_enabled", 0644,
                                    d_tracer, NULL, &ftrace_profile_fops);
        if (!entry)
                pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
}

#else /* CONFIG_FUNCTION_PROFILER */
static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
{
}

#endif /* CONFIG_FUNCTION_PROFILER */

#ifdef CONFIG_DYNAMIC_FTRACE

static struct ftrace_ops *removed_ops;

/*
 * Set when doing a global update, like enabling all recs or disabling them.
 * It is not set when just updating a single ftrace_ops.
 */
static bool update_all_ops;

#ifndef CONFIG_FTRACE_MCOUNT_RECORD
# error Dynamic ftrace depends on MCOUNT_RECORD
#endif

struct ftrace_func_probe {
        struct ftrace_probe_ops *probe_ops;
        struct ftrace_ops       ops;
        struct trace_array      *tr;
        struct list_head        list;
        void                    *data;
        int                     ref;
};

/*
 * We make these constant because no one should touch them,
 * but they are used as the default "empty hash", to avoid allocating
 * it all the time. These are in a read only section such that if
 * anyone does try to modify it, it will cause an exception.
 */
static const struct hlist_head empty_buckets[1];
static const struct ftrace_hash empty_hash = {
        .buckets = (struct hlist_head *)empty_buckets,
};
#define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)

struct ftrace_ops global_ops = {
        .func                           = ftrace_stub,
        .local_hash.notrace_hash        = EMPTY_HASH,
        .local_hash.filter_hash         = EMPTY_HASH,
        INIT_OPS_HASH(global_ops)
        .flags                          = FTRACE_OPS_FL_INITIALIZED |
                                          FTRACE_OPS_FL_PID,
};

/*
 * Used by the stack unwinder to know about dynamic ftrace trampolines.
 */
struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
{
        struct ftrace_ops *op = NULL;

        /*
         * Some of the ops may be dynamically allocated,
         * they are freed after a synchronize_rcu().
         */
        preempt_disable_notrace();

        do_for_each_ftrace_op(op, ftrace_ops_list) {
                /*
                 * This is to check for dynamically allocated trampolines.
                 * Trampolines that are in kernel text will have
                 * core_kernel_text() return true.
                 */
                if (op->trampoline && op->trampoline_size)
                        if (addr >= op->trampoline &&
                            addr < op->trampoline + op->trampoline_size) {
                                preempt_enable_notrace();
                                return op;
                        }
        } while_for_each_ftrace_op(op);
        preempt_enable_notrace();

        return NULL;
}

/*
 * This is used by __kernel_text_address() to return true if the
 * address is on a dynamically allocated trampoline that would
 * not return true for either core_kernel_text() or
 * is_module_text_address().
 */
bool is_ftrace_trampoline(unsigned long addr)
{
        return ftrace_ops_trampoline(addr) != NULL;
}

struct ftrace_page {
        struct ftrace_page      *next;
        struct dyn_ftrace       *records;
        int                     index;
        int                     order;
};

#define ENTRY_SIZE sizeof(struct dyn_ftrace)
#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)

static struct ftrace_page       *ftrace_pages_start;
static struct ftrace_page       *ftrace_pages;

static __always_inline unsigned long
ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
{
        if (hash->size_bits > 0)
                return hash_long(ip, hash->size_bits);

        return 0;
}

/* Only use this function if ftrace_hash_empty() has already been tested */
static __always_inline struct ftrace_func_entry *
__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
{
        unsigned long key;
        struct ftrace_func_entry *entry;
        struct hlist_head *hhd;

        key = ftrace_hash_key(hash, ip);
        hhd = &hash->buckets[key];

        hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
                if (entry->ip == ip)
                        return entry;
        }
        return NULL;
}

/**
 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
 * @hash: The hash to look at
 * @ip: The instruction pointer to test
 *
 * Search a given @hash to see if a given instruction pointer (@ip)
 * exists in it.
 *
 * Returns the entry that holds the @ip if found. NULL otherwise.
 */
struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
{
        if (ftrace_hash_empty(hash))
                return NULL;

        return __ftrace_lookup_ip(hash, ip);
}

static void __add_hash_entry(struct ftrace_hash *hash,
                             struct ftrace_func_entry *entry)
{
        struct hlist_head *hhd;
        unsigned long key;

        key = ftrace_hash_key(hash, entry->ip);
        hhd = &hash->buckets[key];
        hlist_add_head(&entry->hlist, hhd);
        hash->count++;
}

static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
{
        struct ftrace_func_entry *entry;

        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;

        entry->ip = ip;
        __add_hash_entry(hash, entry);

        return 0;
}

static void
free_hash_entry(struct ftrace_hash *hash,
                  struct ftrace_func_entry *entry)
{
        hlist_del(&entry->hlist);
        kfree(entry);
        hash->count--;
}

static void
remove_hash_entry(struct ftrace_hash *hash,
                  struct ftrace_func_entry *entry)
{
        hlist_del_rcu(&entry->hlist);
        hash->count--;
}

static void ftrace_hash_clear(struct ftrace_hash *hash)
{
        struct hlist_head *hhd;
        struct hlist_node *tn;
        struct ftrace_func_entry *entry;
        int size = 1 << hash->size_bits;
        int i;

        if (!hash->count)
                return;

        for (i = 0; i < size; i++) {
                hhd = &hash->buckets[i];
                hlist_for_each_entry_safe(entry, tn, hhd, hlist)
                        free_hash_entry(hash, entry);
        }
        FTRACE_WARN_ON(hash->count);
}

static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
{
        list_del(&ftrace_mod->list);
        kfree(ftrace_mod->module);
        kfree(ftrace_mod->func);
        kfree(ftrace_mod);
}

static void clear_ftrace_mod_list(struct list_head *head)
{
        struct ftrace_mod_load *p, *n;

        /* stack tracer isn't supported yet */
        if (!head)
                return;

        mutex_lock(&ftrace_lock);
        list_for_each_entry_safe(p, n, head, list)
                free_ftrace_mod(p);
        mutex_unlock(&ftrace_lock);
}

static void free_ftrace_hash(struct ftrace_hash *hash)
{
        if (!hash || hash == EMPTY_HASH)
                return;
        ftrace_hash_clear(hash);
        kfree(hash->buckets);
        kfree(hash);
}

static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
{
        struct ftrace_hash *hash;

        hash = container_of(rcu, struct ftrace_hash, rcu);
        free_ftrace_hash(hash);
}

static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
{
        if (!hash || hash == EMPTY_HASH)
                return;
        call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
}

void ftrace_free_filter(struct ftrace_ops *ops)
{
        ftrace_ops_init(ops);
        free_ftrace_hash(ops->func_hash->filter_hash);
        free_ftrace_hash(ops->func_hash->notrace_hash);
}

static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
{
        struct ftrace_hash *hash;
        int size;

        hash = kzalloc(sizeof(*hash), GFP_KERNEL);
        if (!hash)
                return NULL;

        size = 1 << size_bits;
        hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);

        if (!hash->buckets) {
                kfree(hash);
                return NULL;
        }

        hash->size_bits = size_bits;

        return hash;
}


static int ftrace_add_mod(struct trace_array *tr,
                          const char *func, const char *module,
                          int enable)
{
        struct ftrace_mod_load *ftrace_mod;
        struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;

        ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
        if (!ftrace_mod)
                return -ENOMEM;

        ftrace_mod->func = kstrdup(func, GFP_KERNEL);
        ftrace_mod->module = kstrdup(module, GFP_KERNEL);
        ftrace_mod->enable = enable;

        if (!ftrace_mod->func || !ftrace_mod->module)
                goto out_free;

        list_add(&ftrace_mod->list, mod_head);

        return 0;

 out_free:
        free_ftrace_mod(ftrace_mod);

        return -ENOMEM;
}

static struct ftrace_hash *
alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
{
        struct ftrace_func_entry *entry;
        struct ftrace_hash *new_hash;
        int size;
        int ret;
        int i;

        new_hash = alloc_ftrace_hash(size_bits);
        if (!new_hash)
                return NULL;

        if (hash)
                new_hash->flags = hash->flags;

        /* Empty hash? */
        if (ftrace_hash_empty(hash))
                return new_hash;

        size = 1 << hash->size_bits;
        for (i = 0; i < size; i++) {
                hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
                        ret = add_hash_entry(new_hash, entry->ip);
                        if (ret < 0)
                                goto free_hash;
                }
        }

        FTRACE_WARN_ON(new_hash->count != hash->count);

        return new_hash;

 free_hash:
        free_ftrace_hash(new_hash);
        return NULL;
}

static void
ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
static void
ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);

static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
                                       struct ftrace_hash *new_hash);

static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
{
        struct ftrace_func_entry *entry;
        struct ftrace_hash *new_hash;
        struct hlist_head *hhd;
        struct hlist_node *tn;
        int bits = 0;
        int i;

        /*
         * Use around half the size (max bit of it), but
         * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
         */
        bits = fls(size / 2);

        /* Don't allocate too much */
        if (bits > FTRACE_HASH_MAX_BITS)
                bits = FTRACE_HASH_MAX_BITS;

        new_hash = alloc_ftrace_hash(bits);
        if (!new_hash)
                return NULL;

        new_hash->flags = src->flags;

        size = 1 << src->size_bits;
        for (i = 0; i < size; i++) {
                hhd = &src->buckets[i];
                hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
                        remove_hash_entry(src, entry);
                        __add_hash_entry(new_hash, entry);
                }
        }
        return new_hash;
}

static struct ftrace_hash *
__ftrace_hash_move(struct ftrace_hash *src)
{
        int size = src->count;

        /*
         * If the new source is empty, just return the empty_hash.
         */
        if (ftrace_hash_empty(src))
                return EMPTY_HASH;

        return dup_hash(src, size);
}

static int
ftrace_hash_move(struct ftrace_ops *ops, int enable,
                 struct ftrace_hash **dst, struct ftrace_hash *src)
{
        struct ftrace_hash *new_hash;
        int ret;

        /* Reject setting notrace hash on IPMODIFY ftrace_ops */
        if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
                return -EINVAL;

        new_hash = __ftrace_hash_move(src);
        if (!new_hash)
                return -ENOMEM;

        /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
        if (enable) {
                /* IPMODIFY should be updated only when filter_hash updating */
                ret = ftrace_hash_ipmodify_update(ops, new_hash);
                if (ret < 0) {
                        free_ftrace_hash(new_hash);
                        return ret;
                }
        }

        /*
         * Remove the current set, update the hash and add
         * them back.
         */
        ftrace_hash_rec_disable_modify(ops, enable);

        rcu_assign_pointer(*dst, new_hash);

        ftrace_hash_rec_enable_modify(ops, enable);

        return 0;
}

static bool hash_contains_ip(unsigned long ip,
                             struct ftrace_ops_hash *hash)
{
        /*
         * The function record is a match if it exists in the filter
         * hash and not in the notrace hash. Note, an empty hash is
         * considered a match for the filter hash, but an empty
         * notrace hash is considered not in the notrace hash.
         */
        return (ftrace_hash_empty(hash->filter_hash) ||
                __ftrace_lookup_ip(hash->filter_hash, ip)) &&
                (ftrace_hash_empty(hash->notrace_hash) ||
                 !__ftrace_lookup_ip(hash->notrace_hash, ip));
}

/*
 * Test the hashes for this ops to see if we want to call
 * the ops->func or not.
 *
 * It's a match if the ip is in the ops->filter_hash or
 * the filter_hash does not exist or is empty,
 *  AND
 * the ip is not in the ops->notrace_hash.
 *
 * This needs to be called with preemption disabled as
 * the hashes are freed with call_rcu().
 */
int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
        struct ftrace_ops_hash hash;
        int ret;

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
        /*
         * There's a small race when adding ops that the ftrace handler
         * that wants regs, may be called without them. We can not
         * allow that handler to be called if regs is NULL.
         */
        if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
                return 0;
#endif

        rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
        rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);

        if (hash_contains_ip(ip, &hash))
                ret = 1;
        else
                ret = 0;

        return ret;
}

/*
 * This is a double for. Do not use 'break' to break out of the loop,
 * you must use a goto.
 */
#define do_for_each_ftrace_rec(pg, rec)                                 \
        for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
                int _____i;                                             \
                for (_____i = 0; _____i < pg->index; _____i++) {        \
                        rec = &pg->records[_____i];

#define while_for_each_ftrace_rec()             \
                }                               \
        }


static int ftrace_cmp_recs(const void *a, const void *b)
{
        const struct dyn_ftrace *key = a;
        const struct dyn_ftrace *rec = b;

        if (key->flags < rec->ip)
                return -1;
        if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
                return 1;
        return 0;
}

static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
{
        struct ftrace_page *pg;
        struct dyn_ftrace *rec = NULL;
        struct dyn_ftrace key;

        key.ip = start;
        key.flags = end;        /* overload flags, as it is unsigned long */

        for (pg = ftrace_pages_start; pg; pg = pg->next) {
                if (end < pg->records[0].ip ||
                    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
                        continue;
                rec = bsearch(&key, pg->records, pg->index,
                              sizeof(struct dyn_ftrace),
                              ftrace_cmp_recs);
                if (rec)
                        break;
        }
        return rec;
}

/**
 * ftrace_location_range - return the first address of a traced location
 *      if it touches the given ip range
 * @start: start of range to search.
 * @end: end of range to search (inclusive). @end points to the last byte
 *      to check.
 *
 * Returns rec->ip if the related ftrace location is a least partly within
 * the given address range. That is, the first address of the instruction
 * that is either a NOP or call to the function tracer. It checks the ftrace
 * internal tables to determine if the address belongs or not.
 */
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
        struct dyn_ftrace *rec;

        rec = lookup_rec(start, end);
        if (rec)
                return rec->ip;

        return 0;
}

/**
 * ftrace_location - return true if the ip giving is a traced location
 * @ip: the instruction pointer to check
 *
 * Returns rec->ip if @ip given is a pointer to a ftrace location.
 * That is, the instruction that is either a NOP or call to
 * the function tracer. It checks the ftrace internal tables to
 * determine if the address belongs or not.
 */
unsigned long ftrace_location(unsigned long ip)
{
        return ftrace_location_range(ip, ip);
}

/**
 * ftrace_text_reserved - return true if range contains an ftrace location
 * @start: start of range to search
 * @end: end of range to search (inclusive). @end points to the last byte to check.
 *
 * Returns 1 if @start and @end contains a ftrace location.
 * That is, the instruction that is either a NOP or call to
 * the function tracer. It checks the ftrace internal tables to
 * determine if the address belongs or not.
 */
int ftrace_text_reserved(const void *start, const void *end)
{
        unsigned long ret;

        ret = ftrace_location_range((unsigned long)start,
                                    (unsigned long)end);

        return (int)!!ret;
}

/* Test if ops registered to this rec needs regs */
static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
{
        struct ftrace_ops *ops;
        bool keep_regs = false;

        for (ops = ftrace_ops_list;
             ops != &ftrace_list_end; ops = ops->next) {
                /* pass rec in as regs to have non-NULL val */
                if (ftrace_ops_test(ops, rec->ip, rec)) {
                        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
                                keep_regs = true;
                                break;
                        }
                }
        }

        return  keep_regs;
}

static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
static struct ftrace_ops *
ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
static struct ftrace_ops *
ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);

static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
                                     int filter_hash,
                                     bool inc)
{
        struct ftrace_hash *hash;
        struct ftrace_hash *other_hash;
        struct ftrace_page *pg;
        struct dyn_ftrace *rec;
        bool update = false;
        int count = 0;
        int all = false;

        /* Only update if the ops has been registered */
        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
                return false;

        /*
         * In the filter_hash case:
         *   If the count is zero, we update all records.
         *   Otherwise we just update the items in the hash.
         *
         * In the notrace_hash case:
         *   We enable the update in the hash.
         *   As disabling notrace means enabling the tracing,
         *   and enabling notrace means disabling, the inc variable
         *   gets inversed.
         */
        if (filter_hash) {
                hash = ops->func_hash->filter_hash;
                other_hash = ops->func_hash->notrace_hash;
                if (ftrace_hash_empty(hash))
                        all = true;
        } else {
                inc = !inc;
                hash = ops->func_hash->notrace_hash;
                other_hash = ops->func_hash->filter_hash;
                /*
                 * If the notrace hash has no items,
                 * then there's nothing to do.
                 */
                if (ftrace_hash_empty(hash))
                        return false;
        }

        do_for_each_ftrace_rec(pg, rec) {
                int in_other_hash = 0;
                int in_hash = 0;
                int match = 0;

                if (rec->flags & FTRACE_FL_DISABLED)
                        continue;

                if (all) {
                        /*
                         * Only the filter_hash affects all records.
                         * Update if the record is not in the notrace hash.
                         */
                        if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
                                match = 1;
                } else {
                        in_hash = !!ftrace_lookup_ip(hash, rec->ip);
                        in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);

                        /*
                         * If filter_hash is set, we want to match all functions
                         * that are in the hash but not in the other hash.
                         *
                         * If filter_hash is not set, then we are decrementing.
                         * That means we match anything that is in the hash
                         * and also in the other_hash. That is, we need to turn
                         * off functions in the other hash because they are disabled
                         * by this hash.
                         */
                        if (filter_hash && in_hash && !in_other_hash)
                                match = 1;
                        else if (!filter_hash && in_hash &&
                                 (in_other_hash || ftrace_hash_empty(other_hash)))
                                match = 1;
                }
                if (!match)
                        continue;

                if (inc) {
                        rec->flags++;
                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
                                return false;

                        if (ops->flags & FTRACE_OPS_FL_DIRECT)
                                rec->flags |= FTRACE_FL_DIRECT;

                        /*
                         * If there's only a single callback registered to a
                         * function, and the ops has a trampoline registered
                         * for it, then we can call it directly.
                         */
                        if (ftrace_rec_count(rec) == 1 && ops->trampoline)
                                rec->flags |= FTRACE_FL_TRAMP;
                        else
                                /*
                                 * If we are adding another function callback
                                 * to this function, and the previous had a
                                 * custom trampoline in use, then we need to go
                                 * back to the default trampoline.
                                 */
                                rec->flags &= ~FTRACE_FL_TRAMP;

                        /*
                         * If any ops wants regs saved for this function
                         * then all ops will get saved regs.
                         */
                        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
                                rec->flags |= FTRACE_FL_REGS;
                } else {
                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
                                return false;
                        rec->flags--;

                        /*
                         * Only the internal direct_ops should have the
                         * DIRECT flag set. Thus, if it is removing a
                         * function, then that function should no longer
                         * be direct.
                         */
                        if (ops->flags & FTRACE_OPS_FL_DIRECT)
                                rec->flags &= ~FTRACE_FL_DIRECT;

                        /*
                         * If the rec had REGS enabled and the ops that is
                         * being removed had REGS set, then see if there is
                         * still any ops for this record that wants regs.
                         * If not, we can stop recording them.
                         */
                        if (ftrace_rec_count(rec) > 0 &&
                            rec->flags & FTRACE_FL_REGS &&
                            ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
                                if (!test_rec_ops_needs_regs(rec))
                                        rec->flags &= ~FTRACE_FL_REGS;
                        }

                        /*
                         * The TRAMP needs to be set only if rec count
                         * is decremented to one, and the ops that is
                         * left has a trampoline. As TRAMP can only be
                         * enabled if there is only a single ops attached
                         * to it.
                         */
                        if (ftrace_rec_count(rec) == 1 &&
                            ftrace_find_tramp_ops_any_other(rec, ops))
                                rec->flags |= FTRACE_FL_TRAMP;
                        else
                                rec->flags &= ~FTRACE_FL_TRAMP;

                        /*
                         * flags will be cleared in ftrace_check_record()
                         * if rec count is zero.
                         */
                }
                count++;

                /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
                update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;

                /* Shortcut, if we handled all records, we are done. */
                if (!all && count == hash->count)
                        return update;
        } while_for_each_ftrace_rec();

        return update;
}

static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
                                    int filter_hash)
{
        return __ftrace_hash_rec_update(ops, filter_hash, 0);
}

static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
                                   int filter_hash)
{
        return __ftrace_hash_rec_update(ops, filter_hash, 1);
}

static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
                                          int filter_hash, int inc)
{
        struct ftrace_ops *op;

        __ftrace_hash_rec_update(ops, filter_hash, inc);

        if (ops->func_hash != &global_ops.local_hash)
                return;

        /*
         * If the ops shares the global_ops hash, then we need to update
         * all ops that are enabled and use this hash.
         */
        do_for_each_ftrace_op(op, ftrace_ops_list) {
                /* Already done */
                if (op == ops)
                        continue;
                if (op->func_hash == &global_ops.local_hash)
                        __ftrace_hash_rec_update(op, filter_hash, inc);
        } while_for_each_ftrace_op(op);
}

static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
                                           int filter_hash)
{
        ftrace_hash_rec_update_modify(ops, filter_hash, 0);
}

static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
                                          int filter_hash)
{
        ftrace_hash_rec_update_modify(ops, filter_hash, 1);
}

/*
 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
 * or no-needed to update, -EBUSY if it detects a conflict of the flag
 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
 * Note that old_hash and new_hash has below meanings
 *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
 *  - If the hash is EMPTY_HASH, it hits nothing
 *  - Anything else hits the recs which match the hash entries.
 */
static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
                                         struct ftrace_hash *old_hash,
                                         struct ftrace_hash *new_hash)
{
        struct ftrace_page *pg;
        struct dyn_ftrace *rec, *end = NULL;
        int in_old, in_new;

        /* Only update if the ops has been registered */
        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
                return 0;

        if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
                return 0;

        /*
         * Since the IPMODIFY is a very address sensitive action, we do not
         * allow ftrace_ops to set all functions to new hash.
         */
        if (!new_hash || !old_hash)
                return -EINVAL;

        /* Update rec->flags */
        do_for_each_ftrace_rec(pg, rec) {

                if (rec->flags & FTRACE_FL_DISABLED)
                        continue;

                /* We need to update only differences of filter_hash */
                in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
                in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
                if (in_old == in_new)
                        continue;

                if (in_new) {
                        /* New entries must ensure no others are using it */
                        if (rec->flags & FTRACE_FL_IPMODIFY)
                                goto rollback;
                        rec->flags |= FTRACE_FL_IPMODIFY;
                } else /* Removed entry */
                        rec->flags &= ~FTRACE_FL_IPMODIFY;
        } while_for_each_ftrace_rec();

        return 0;

rollback:
        end = rec;

        /* Roll back what we did above */
        do_for_each_ftrace_rec(pg, rec) {

                if (rec->flags & FTRACE_FL_DISABLED)
                        continue;

                if (rec == end)
                        goto err_out;

                in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
                in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
                if (in_old == in_new)
                        continue;

                if (in_new)
                        rec->flags &= ~FTRACE_FL_IPMODIFY;
                else
                        rec->flags |= FTRACE_FL_IPMODIFY;
        } while_for_each_ftrace_rec();

err_out:
        return -EBUSY;
}

static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
{
        struct ftrace_hash *hash = ops->func_hash->filter_hash;

        if (ftrace_hash_empty(hash))
                hash = NULL;

        return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
}

/* Disabling always succeeds */
static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
{
        struct ftrace_hash *hash = ops->func_hash->filter_hash;

        if (ftrace_hash_empty(hash))
                hash = NULL;

        __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
}

static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
                                       struct ftrace_hash *new_hash)
{
        struct ftrace_hash *old_hash = ops->func_hash->filter_hash;

        if (ftrace_hash_empty(old_hash))
                old_hash = NULL;

        if (ftrace_hash_empty(new_hash))
                new_hash = NULL;

        return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
}

static void print_ip_ins(const char *fmt, const unsigned char *p)
{
        char ins[MCOUNT_INSN_SIZE];
        int i;

        if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
                printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
                return;
        }

        printk(KERN_CONT "%s", fmt);

        for (i = 0; i < MCOUNT_INSN_SIZE; i++)
                printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
}

enum ftrace_bug_type ftrace_bug_type;
const void *ftrace_expected;

static void print_bug_type(void)
{
        switch (ftrace_bug_type) {
        case FTRACE_BUG_UNKNOWN:
                break;
        case FTRACE_BUG_INIT:
                pr_info("Initializing ftrace call sites\n");
                break;
        case FTRACE_BUG_NOP:
                pr_info("Setting ftrace call site to NOP\n");
                break;
        case FTRACE_BUG_CALL:
                pr_info("Setting ftrace call site to call ftrace function\n");
                break;

        case FTRACE_BUG_UPDATE:
                pr_info("Updating ftrace call site to call a different ftrace function\n");
                break;
        }
}

/**
 * ftrace_bug - report and shutdown function tracer
 * @failed: The failed type (EFAULT, EINVAL, EPERM)
 * @rec: The record that failed
 *
 * The arch code that enables or disables the function tracing
 * can call ftrace_bug() when it has detected a problem in
 * modifying the code. @failed should be one of either:
 * EFAULT - if the problem happens on reading the @ip address
 * EINVAL - if what is read at @ip is not what was expected
 * EPERM - if the problem happens on writing to the @ip address
 */
void ftrace_bug(int failed, struct dyn_ftrace *rec)
{
        unsigned long ip = rec ? rec->ip : 0;

        pr_info("------------[ ftrace bug ]------------\n");

        switch (failed) {
        case -EFAULT:
                pr_info("ftrace faulted on modifying ");
                print_ip_sym(KERN_INFO, ip);
                break;
        case -EINVAL:
                pr_info("ftrace failed to modify ");
                print_ip_sym(KERN_INFO, ip);
                print_ip_ins(" actual:   ", (unsigned char *)ip);
                pr_cont("\n");
                if (ftrace_expected) {
                        print_ip_ins(" expected: ", ftrace_expected);
                        pr_cont("\n");
                }
                break;
        case -EPERM:
                pr_info("ftrace faulted on writing ");
                print_ip_sym(KERN_INFO, ip);
                break;
        default:
                pr_info("ftrace faulted on unknown error ");
                print_ip_sym(KERN_INFO, ip);
        }
        print_bug_type();
        if (rec) {
                struct ftrace_ops *ops = NULL;

                pr_info("ftrace record flags: %lx\n", rec->flags);
                pr_cont(" (%ld)%s", ftrace_rec_count(rec),
                        rec->flags & FTRACE_FL_REGS ? " R" : "  ");
                if (rec->flags & FTRACE_FL_TRAMP_EN) {
                        ops = ftrace_find_tramp_ops_any(rec);
                        if (ops) {
                                do {
                                        pr_cont("\ttramp: %pS (%pS)",
                                                (void *)ops->trampoline,
                                                (void *)ops->func);
                                        ops = ftrace_find_tramp_ops_next(rec, ops);
                                } while (ops);
                        } else
                                pr_cont("\ttramp: ERROR!");

                }
                ip = ftrace_get_addr_curr(rec);
                pr_cont("\n expected tramp: %lx\n", ip);
        }

        FTRACE_WARN_ON_ONCE(1);
}

static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
{
        unsigned long flag = 0UL;

        ftrace_bug_type = FTRACE_BUG_UNKNOWN;

        if (rec->flags & FTRACE_FL_DISABLED)
                return FTRACE_UPDATE_IGNORE;

        /*
         * If we are updating calls:
         *
         *   If the record has a ref count, then we need to enable it
         *   because someone is using it.
         *
         *   Otherwise we make sure its disabled.
         *
         * If we are disabling calls, then disable all records that
         * are enabled.
         */
        if (enable && ftrace_rec_count(rec))
                flag = FTRACE_FL_ENABLED;

        /*
         * If enabling and the REGS flag does not match the REGS_EN, or
         * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
         * this record. Set flags to fail the compare against ENABLED.
         * Same for direct calls.
         */
        if (flag) {
                if (!(rec->flags & FTRACE_FL_REGS) !=
                    !(rec->flags & FTRACE_FL_REGS_EN))
                        flag |= FTRACE_FL_REGS;

                if (!(rec->flags & FTRACE_FL_TRAMP) !=
                    !(rec->flags & FTRACE_FL_TRAMP_EN))
                        flag |= FTRACE_FL_TRAMP;

                /*
                 * Direct calls are special, as count matters.
                 * We must test the record for direct, if the
                 * DIRECT and DIRECT_EN do not match, but only
                 * if the count is 1. That's because, if the
                 * count is something other than one, we do not
                 * want the direct enabled (it will be done via the
                 * direct helper). But if DIRECT_EN is set, and
                 * the count is not one, we need to clear it.
                 */
                if (ftrace_rec_count(rec) == 1) {
                        if (!(rec->flags & FTRACE_FL_DIRECT) !=
                            !(rec->flags & FTRACE_FL_DIRECT_EN))
                                flag |= FTRACE_FL_DIRECT;
                } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
                        flag |= FTRACE_FL_DIRECT;
                }
        }

        /* If the state of this record hasn't changed, then do nothing */
        if ((rec->flags & FTRACE_FL_ENABLED) == flag)
                return FTRACE_UPDATE_IGNORE;

        if (flag) {
                /* Save off if rec is being enabled (for return value) */
                flag ^= rec->flags & FTRACE_FL_ENABLED;

                if (update) {
                        rec->flags |= FTRACE_FL_ENABLED;
                        if (flag & FTRACE_FL_REGS) {
                                if (rec->flags & FTRACE_FL_REGS)
                                        rec->flags |= FTRACE_FL_REGS_EN;
                                else
                                        rec->flags &= ~FTRACE_FL_REGS_EN;
                        }
                        if (flag & FTRACE_FL_TRAMP) {
                                if (rec->flags & FTRACE_FL_TRAMP)
                                        rec->flags |= FTRACE_FL_TRAMP_EN;
                                else
                                        rec->flags &= ~FTRACE_FL_TRAMP_EN;
                        }

                        if (flag & FTRACE_FL_DIRECT) {
                                /*
                                 * If there's only one user (direct_ops helper)
                                 * then we can call the direct function
                                 * directly (no ftrace trampoline).
                                 */
                                if (ftrace_rec_count(rec) == 1) {
                                        if (rec->flags & FTRACE_FL_DIRECT)
                                                rec->flags |= FTRACE_FL_DIRECT_EN;
                                        else
                                                rec->flags &= ~FTRACE_FL_DIRECT_EN;
                                } else {
                                        /*
                                         * Can only call directly if there's
                                         * only one callback to the function.
                                         */
                                        rec->flags &= ~FTRACE_FL_DIRECT_EN;
                                }
                        }
                }

                /*
                 * If this record is being updated from a nop, then
                 *   return UPDATE_MAKE_CALL.
                 * Otherwise,
                 *   return UPDATE_MODIFY_CALL to tell the caller to convert
                 *   from the save regs, to a non-save regs function or
                 *   vice versa, or from a trampoline call.
                 */
                if (flag & FTRACE_FL_ENABLED) {
                        ftrace_bug_type = FTRACE_BUG_CALL;
                        return FTRACE_UPDATE_MAKE_CALL;
                }

                ftrace_bug_type = FTRACE_BUG_UPDATE;
                return FTRACE_UPDATE_MODIFY_CALL;
        }

        if (update) {
                /* If there's no more users, clear all flags */
                if (!ftrace_rec_count(rec))
                        rec->flags = 0;
                else
                        /*
                         * Just disable the record, but keep the ops TRAMP
                         * and REGS states. The _EN flags must be disabled though.
                         */
                        rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
                                        FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
        }

        ftrace_bug_type = FTRACE_BUG_NOP;
        return FTRACE_UPDATE_MAKE_NOP;
}

/**
 * ftrace_update_record, set a record that now is tracing or not
 * @rec: the record to update
 * @enable: set to true if the record is tracing, false to force disable
 *
 * The records that represent all functions that can be traced need
 * to be updated when tracing has been enabled.
 */
int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
{
        return ftrace_check_record(rec, enable, true);
}

/**
 * ftrace_test_record, check if the record has been enabled or not
 * @rec: the record to test
 * @enable: set to true to check if enabled, false if it is disabled
 *
 * The arch code may need to test if a record is already set to
 * tracing to determine how to modify the function code that it
 * represents.
 */
int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
{
        return ftrace_check_record(rec, enable, false);
}

static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
{
        struct ftrace_ops *op;
        unsigned long ip = rec->ip;

        do_for_each_ftrace_op(op, ftrace_ops_list) {

                if (!op->trampoline)
                        continue;

                if (hash_contains_ip(ip, op->func_hash))
                        return op;
        } while_for_each_ftrace_op(op);

        return NULL;
}

static struct ftrace_ops *
ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
{
        struct ftrace_ops *op;
        unsigned long ip = rec->ip;

        do_for_each_ftrace_op(op, ftrace_ops_list) {

                if (op == op_exclude || !op->trampoline)
                        continue;

                if (hash_contains_ip(ip, op->func_hash))
                        return op;
        } while_for_each_ftrace_op(op);

        return NULL;
}

static struct ftrace_ops *
ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
                           struct ftrace_ops *op)
{
        unsigned long ip = rec->ip;

        while_for_each_ftrace_op(op) {

                if (!op->trampoline)
                        continue;

                if (hash_contains_ip(ip, op->func_hash))
                        return op;
        }

        return NULL;
}

static struct ftrace_ops *
ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
{
        struct ftrace_ops *op;
        unsigned long ip = rec->ip;

        /*
         * Need to check removed ops first.
         * If they are being removed, and this rec has a tramp,
         * and this rec is in the ops list, then it would be the
         * one with the tramp.
         */
        if (removed_ops) {
                if (hash_contains_ip(ip, &removed_ops->old_hash))
                        return removed_ops;
        }

        /*
         * Need to find the current trampoline for a rec.
         * Now, a trampoline is only attached to a rec if there
         * was a single 'ops' attached to it. But this can be called
         * when we are adding another op to the rec or removing the
         * current one. Thus, if the op is being added, we can
         * ignore it because it hasn't attached itself to the rec
         * yet.
         *
         * If an ops is being modified (hooking to different functions)
         * then we don't care about the new functions that are being
         * added, just the old ones (that are probably being removed).
         *
         * If we are adding an ops to a function that already is using
         * a trampoline, it needs to be removed (trampolines are only
         * for single ops connected), then an ops that is not being
         * modified also needs to be checked.
         */
        do_for_each_ftrace_op(op, ftrace_ops_list) {

                if (!op->trampoline)
                        continue;

                /*
                 * If the ops is being added, it hasn't gotten to
                 * the point to be removed from this tree yet.
                 */
                if (op->flags & FTRACE_OPS_FL_ADDING)
                        continue;


                /*
                 * If the ops is being modified and is in the old
                 * hash, then it is probably being removed from this
                 * function.
                 */
                if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
                    hash_contains_ip(ip, &op->old_hash))
                        return op;
                /*
                 * If the ops is not being added or modified, and it's
                 * in its normal filter hash, then this must be the one
                 * we want!
                 */
                if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
                    hash_contains_ip(ip, op->func_hash))
                        return op;

        } while_for_each_ftrace_op(op);

        return NULL;
}

static struct ftrace_ops *
ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
{
        struct ftrace_ops *op;
        unsigned long ip = rec->ip;

        do_for_each_ftrace_op(op, ftrace_ops_list) {
                /* pass rec in as regs to have non-NULL val */
                if (hash_contains_ip(ip, op->func_hash))
                        return op;
        } while_for_each_ftrace_op(op);

        return NULL;
}

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/* Protected by rcu_tasks for reading, and direct_mutex for writing */
static struct ftrace_hash *direct_functions = EMPTY_HASH;
static DEFINE_MUTEX(direct_mutex);
int ftrace_direct_func_count;

/*
 * Search the direct_functions hash to see if the given instruction pointer
 * has a direct caller attached to it.
 */
unsigned long ftrace_find_rec_direct(unsigned long ip)
{
        struct ftrace_func_entry *entry;

        entry = __ftrace_lookup_ip(direct_functions, ip);
        if (!entry)
                return 0;

        return entry->direct;
}

static void call_direct_funcs(unsigned long ip, unsigned long pip,
                              struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
        struct pt_regs *regs = ftrace_get_regs(fregs);
        unsigned long addr;

        addr = ftrace_find_rec_direct(ip);
        if (!addr)
                return;

        arch_ftrace_set_direct_caller(regs, addr);
}

struct ftrace_ops direct_ops = {
        .func           = call_direct_funcs,
        .flags          = FTRACE_OPS_FL_IPMODIFY
                          | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
                          | FTRACE_OPS_FL_PERMANENT,
        /*
         * By declaring the main trampoline as this trampoline
         * it will never have one allocated for it. Allocated
         * trampolines should not call direct functions.
         * The direct_ops should only be called by the builtin
         * ftrace_regs_caller trampoline.
         */
        .trampoline     = FTRACE_REGS_ADDR,
};
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */

/**
 * ftrace_get_addr_new - Get the call address to set to
 * @rec:  The ftrace record descriptor
 *
 * If the record has the FTRACE_FL_REGS set, that means that it
 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
 * is not set, then it wants to convert to the normal callback.
 *
 * Returns the address of the trampoline to set to
 */
unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
{
        struct ftrace_ops *ops;
        unsigned long addr;

        if ((rec->flags & FTRACE_FL_DIRECT) &&
            (ftrace_rec_count(rec) == 1)) {
                addr = ftrace_find_rec_direct(rec->ip);
                if (addr)
                        return addr;
                WARN_ON_ONCE(1);
        }

        /* Trampolines take precedence over regs */
        if (rec->flags & FTRACE_FL_TRAMP) {
                ops = ftrace_find_tramp_ops_new(rec);
                if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
                        pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
                                (void *)rec->ip, (void *)rec->ip, rec->flags);
                        /* Ftrace is shutting down, return anything */
                        return (unsigned long)FTRACE_ADDR;
                }
                return ops->trampoline;
        }

        if (rec->flags & FTRACE_FL_REGS)
                return (unsigned long)FTRACE_REGS_ADDR;
        else
                return (unsigned long)FTRACE_ADDR;
}

/**
 * ftrace_get_addr_curr - Get the call address that is already there
 * @rec:  The ftrace record descriptor
 *
 * The FTRACE_FL_REGS_EN is set when the record already points to
 * a function that saves all the regs. Basically the '_EN' version
 * represents the current state of the function.
 *
 * Returns the address of the trampoline that is currently being called
 */
unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
{
        struct ftrace_ops *ops;
        unsigned long addr;

        /* Direct calls take precedence over trampolines */
        if (rec->flags & FTRACE_FL_DIRECT_EN) {
                addr = ftrace_find_rec_direct(rec->ip);
                if (addr)
                        return addr;
                WARN_ON_ONCE(1);
        }

        /* Trampolines take precedence over regs */
        if (rec->flags & FTRACE_FL_TRAMP_EN) {
                ops = ftrace_find_tramp_ops_curr(rec);
                if (FTRACE_WARN_ON(!ops)) {
                        pr_warn("Bad trampoline accounting at: %p (%pS)\n",
                                (void *)rec->ip, (void *)rec->ip);
                        /* Ftrace is shutting down, return anything */
                        return (unsigned long)FTRACE_ADDR;
                }
                return ops->trampoline;
        }

        if (rec->flags & FTRACE_FL_REGS_EN)
                return (unsigned long)FTRACE_REGS_ADDR;
        else
                return (unsigned long)FTRACE_ADDR;
}

static int
__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
{
        unsigned long ftrace_old_addr;
        unsigned long ftrace_addr;
        int ret;

        ftrace_addr = ftrace_get_addr_new(rec);

        /* This needs to be done before we call ftrace_update_record */
        ftrace_old_addr = ftrace_get_addr_curr(rec);

        ret = ftrace_update_record(rec, enable);

        ftrace_bug_type = FTRACE_BUG_UNKNOWN;

        switch (ret) {
        case FTRACE_UPDATE_IGNORE:
                return 0;

        case FTRACE_UPDATE_MAKE_CALL:
                ftrace_bug_type = FTRACE_BUG_CALL;
                return ftrace_make_call(rec, ftrace_addr);

        case FTRACE_UPDATE_MAKE_NOP:
                ftrace_bug_type = FTRACE_BUG_NOP;
                return ftrace_make_nop(NULL, rec, ftrace_old_addr);

        case FTRACE_UPDATE_MODIFY_CALL:
                ftrace_bug_type = FTRACE_BUG_UPDATE;
                return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
        }

        return -1; /* unknown ftrace bug */
}

void __weak ftrace_replace_code(int mod_flags)
{
        struct dyn_ftrace *rec;
        struct ftrace_page *pg;
        bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
        int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
        int failed;

        if (unlikely(ftrace_disabled))
                return;

        do_for_each_ftrace_rec(pg, rec) {

                if (rec->flags & FTRACE_FL_DISABLED)
                        continue;

                failed = __ftrace_replace_code(rec, enable);
                if (failed) {
                        ftrace_bug(failed, rec);
                        /* Stop processing */
                        return;
                }
                if (schedulable)
                        cond_resched();
        } while_for_each_ftrace_rec();
}

struct ftrace_rec_iter {
        struct ftrace_page      *pg;
        int                     index;
};

/**
 * ftrace_rec_iter_start, start up iterating over traced functions
 *
 * Returns an iterator handle that is used to iterate over all
 * the records that represent address locations where functions
 * are traced.
 *
 * May return NULL if no records are available.
 */
struct ftrace_rec_iter *ftrace_rec_iter_start(void)
{
        /*
         * We only use a single iterator.
         * Protected by the ftrace_lock mutex.
         */
        static struct ftrace_rec_iter ftrace_rec_iter;
        struct ftrace_rec_iter *iter = &ftrace_rec_iter;

        iter->pg = ftrace_pages_start;
        iter->index = 0;

        /* Could have empty pages */
        while (iter->pg && !iter->pg->index)
                iter->pg = iter->pg->next;

        if (!iter->pg)
                return NULL;

        return iter;
}

/**
 * ftrace_rec_iter_next, get the next record to process.
 * @iter: The handle to the iterator.
 *
 * Returns the next iterator after the given iterator @iter.
 */
struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
{
        iter->index++;

        if (iter->index >= iter->pg->index) {
                iter->pg = iter->pg->next;
                iter->index = 0;

                /* Could have empty pages */
                while (iter->pg && !iter->pg->index)
                        iter->pg = iter->pg->next;
        }

        if (!iter->pg)
                return NULL;

        return iter;
}

/**
 * ftrace_rec_iter_record, get the record at the iterator location
 * @iter: The current iterator location
 *
 * Returns the record that the current @iter is at.
 */
struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
{
        return &iter->pg->records[iter->index];
}

static int
ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
{
        int ret;

        if (unlikely(ftrace_disabled))
                return 0;

        ret = ftrace_init_nop(mod, rec);
        if (ret) {
                ftrace_bug_type = FTRACE_BUG_INIT;
                ftrace_bug(ret, rec);
                return 0;
        }
        return 1;
}

/*
 * archs can override this function if they must do something
 * before the modifying code is performed.
 */
int __weak ftrace_arch_code_modify_prepare(void)
{
        return 0;
}

/*
 * archs can override this function if they must do something
 * after the modifying code is performed.
 */
int __weak ftrace_arch_code_modify_post_process(void)
{
        return 0;
}

void ftrace_modify_all_code(int command)
{
        int update = command & FTRACE_UPDATE_TRACE_FUNC;
        int mod_flags = 0;
        int err = 0;

        if (command & FTRACE_MAY_SLEEP)
                mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;

        /*
         * If the ftrace_caller calls a ftrace_ops func directly,
         * we need to make sure that it only traces functions it
         * expects to trace. When doing the switch of functions,
         * we need to update to the ftrace_ops_list_func first
         * before the transition between old and new calls are set,
         * as the ftrace_ops_list_func will check the ops hashes
         * to make sure the ops are having the right functions
         * traced.
         */
        if (update) {
                err = ftrace_update_ftrace_func(ftrace_ops_list_func);
                if (FTRACE_WARN_ON(err))
                        return;
        }

        if (command & FTRACE_UPDATE_CALLS)
                ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
        else if (command & FTRACE_DISABLE_CALLS)
                ftrace_replace_code(mod_flags);

        if (update && ftrace_trace_function != ftrace_ops_list_func) {
                function_trace_op = set_function_trace_op;
                smp_wmb();
                /* If irqs are disabled, we are in stop machine */
                if (!irqs_disabled())
                        smp_call_function(ftrace_sync_ipi, NULL, 1);
                err = ftrace_update_ftrace_func(ftrace_trace_function);
                if (FTRACE_WARN_ON(err))
                        return;
        }

        if (command & FTRACE_START_FUNC_RET)
                err = ftrace_enable_ftrace_graph_caller();
        else if (command & FTRACE_STOP_FUNC_RET)
                err = ftrace_disable_ftrace_graph_caller();
        FTRACE_WARN_ON(err);
}

static int __ftrace_modify_code(void *data)
{
        int *command = data;

        ftrace_modify_all_code(*command);

        return 0;
}

/**
 * ftrace_run_stop_machine, go back to the stop machine method
 * @command: The command to tell ftrace what to do
 *
 * If an arch needs to fall back to the stop machine method, the
 * it can call this function.
 */
void ftrace_run_stop_machine(int command)
{
        stop_machine(__ftrace_modify_code, &command, NULL);
}

/**
 * arch_ftrace_update_code, modify the code to trace or not trace
 * @command: The command that needs to be done
 *
 * Archs can override this function if it does not need to
 * run stop_machine() to modify code.
 */
void __weak arch_ftrace_update_code(int command)
{
        ftrace_run_stop_machine(command);
}

static void ftrace_run_update_code(int command)
{
        int ret;

        ret = ftrace_arch_code_modify_prepare();
        FTRACE_WARN_ON(ret);
        if (ret)
                return;

        /*
         * By default we use stop_machine() to modify the code.
         * But archs can do what ever they want as long as it
         * is safe. The stop_machine() is the safest, but also
         * produces the most overhead.
         */
        arch_ftrace_update_code(command);

        ret = ftrace_arch_code_modify_post_process();
        FTRACE_WARN_ON(ret);
}

static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
                                   struct ftrace_ops_hash *old_hash)
{
        ops->flags |= FTRACE_OPS_FL_MODIFYING;
        ops->old_hash.filter_hash = old_hash->filter_hash;
        ops->old_hash.notrace_hash = old_hash->notrace_hash;
        ftrace_run_update_code(command);
        ops->old_hash.filter_hash = NULL;
        ops->old_hash.notrace_hash = NULL;
        ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
}

static ftrace_func_t saved_ftrace_func;
static int ftrace_start_up;

void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
{
}

/* List of trace_ops that have allocated trampolines */
static LIST_HEAD(ftrace_ops_trampoline_list);

static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
{
        lockdep_assert_held(&ftrace_lock);
        list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
}

static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
{
        lockdep_assert_held(&ftrace_lock);
        list_del_rcu(&ops->list);
        synchronize_rcu();
}

/*
 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
 * not a module.
 */
#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"

static void ftrace_trampoline_free(struct ftrace_ops *ops)
{
        if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
            ops->trampoline) {
                /*
                 * Record the text poke event before the ksymbol unregister
                 * event.
                 */
                perf_event_text_poke((void *)ops->trampoline,
                                     (void *)ops->trampoline,
                                     ops->trampoline_size, NULL, 0);
                perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
                                   ops->trampoline, ops->trampoline_size,
                                   true, FTRACE_TRAMPOLINE_SYM);
                /* Remove from kallsyms after the perf events */
                ftrace_remove_trampoline_from_kallsyms(ops);
        }

        arch_ftrace_trampoline_free(ops);
}

static void ftrace_startup_enable(int command)
{
        if (saved_ftrace_func != ftrace_trace_function) {
                saved_ftrace_func = ftrace_trace_function;
                command |= FTRACE_UPDATE_TRACE_FUNC;
        }

        if (!command || !ftrace_enabled)
                return;

        ftrace_run_update_code(command);
}

static void ftrace_startup_all(int command)
{
        update_all_ops = true;
        ftrace_startup_enable(command);
        update_all_ops = false;
}

int ftrace_startup(struct ftrace_ops *ops, int command)
{
        int ret;

        if (unlikely(ftrace_disabled))
                return -ENODEV;

        ret = __register_ftrace_function(ops);
        if (ret)
                return ret;

        ftrace_start_up++;

        /*
         * Note that ftrace probes uses this to start up
         * and modify functions it will probe. But we still
         * set the ADDING flag for modification, as probes
         * do not have trampolines. If they add them in the
         * future, then the probes will need to distinguish
         * between adding and updating probes.
         */
        ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;

        ret = ftrace_hash_ipmodify_enable(ops);
        if (ret < 0) {
                /* Rollback registration process */
                __unregister_ftrace_function(ops);
                ftrace_start_up--;
                ops->flags &= ~FTRACE_OPS_FL_ENABLED;
                if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
                        ftrace_trampoline_free(ops);
                return ret;
        }

        if (ftrace_hash_rec_enable(ops, 1))
                command |= FTRACE_UPDATE_CALLS;

        ftrace_startup_enable(command);

        ops->flags &= ~FTRACE_OPS_FL_ADDING;

        return 0;
}

int ftrace_shutdown(struct ftrace_ops *ops, int command)
{
        int ret;

        if (unlikely(ftrace_disabled))
                return -ENODEV;

        ret = __unregister_ftrace_function(ops);
        if (ret)
                return ret;

        ftrace_start_up--;
        /*
         * Just warn in case of unbalance, no need to kill ftrace, it's not
         * critical but the ftrace_call callers may be never nopped again after
         * further ftrace uses.
         */
        WARN_ON_ONCE(ftrace_start_up < 0);

        /* Disabling ipmodify never fails */
        ftrace_hash_ipmodify_disable(ops);

        if (ftrace_hash_rec_disable(ops, 1))
                command |= FTRACE_UPDATE_CALLS;

        ops->flags &= ~FTRACE_OPS_FL_ENABLED;

        if (saved_ftrace_func != ftrace_trace_function) {
                saved_ftrace_func = ftrace_trace_function;
                command |= FTRACE_UPDATE_TRACE_FUNC;
        }

        if (!command || !ftrace_enabled) {
                /*
                 * If these are dynamic or per_cpu ops, they still
                 * need their data freed. Since, function tracing is
                 * not currently active, we can just free them
                 * without synchronizing all CPUs.
                 */
                if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
                        goto free_ops;

                return 0;
        }

        /*
         * If the ops uses a trampoline, then it needs to be
         * tested first on update.
         */
        ops->flags |= FTRACE_OPS_FL_REMOVING;
        removed_ops = ops;

        /* The trampoline logic checks the old hashes */
        ops->old_hash.filter_hash = ops->func_hash->filter_hash;
        ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;

        ftrace_run_update_code(command);

        /*
         * If there's no more ops registered with ftrace, run a
         * sanity check to make sure all rec flags are cleared.
         */
        if (rcu_dereference_protected(ftrace_ops_list,
                        lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                struct ftrace_page *pg;
                struct dyn_ftrace *rec;

                do_for_each_ftrace_rec(pg, rec) {
                        if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
                                pr_warn("  %pS flags:%lx\n",
                                        (void *)rec->ip, rec->flags);
                } while_for_each_ftrace_rec();
        }

        ops->old_hash.filter_hash = NULL;
        ops->old_hash.notrace_hash = NULL;

        removed_ops = NULL;
        ops->flags &= ~FTRACE_OPS_FL_REMOVING;

        /*
         * Dynamic ops may be freed, we must make sure that all
         * callers are done before leaving this function.
         * The same goes for freeing the per_cpu data of the per_cpu
         * ops.
         */
        if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
                /*
                 * We need to do a hard force of sched synchronization.
                 * This is because we use preempt_disable() to do RCU, but
                 * the function tracers can be called where RCU is not watching
                 * (like before user_exit()). We can not rely on the RCU
                 * infrastructure to do the synchronization, thus we must do it

                 * ourselves.
                 */
                synchronize_rcu_tasks_rude();

                /*
                 * When the kernel is preemptive, tasks can be preempted
                 * while on a ftrace trampoline. Just scheduling a task on
                 * a CPU is not good enough to flush them. Calling
                 * synchronize_rcu_tasks() will wait for those tasks to
                 * execute and either schedule voluntarily or enter user space.
                 */
                if (IS_ENABLED(CONFIG_PREEMPTION))
                        synchronize_rcu_tasks();

 free_ops:
                ftrace_trampoline_free(ops);
        }

        return 0;
}

static void ftrace_startup_sysctl(void)
{
        int command;

        if (unlikely(ftrace_disabled))
                return;

        /* Force update next time */
        saved_ftrace_func = NULL;
        /* ftrace_start_up is true if we want ftrace running */
        if (ftrace_start_up) {
                command = FTRACE_UPDATE_CALLS;
                if (ftrace_graph_active)
                        command |= FTRACE_START_FUNC_RET;
                ftrace_startup_enable(command);
        }
}

static void ftrace_shutdown_sysctl(void)
{
        int command;

        if (unlikely(ftrace_disabled))
                return;

        /* ftrace_start_up is true if ftrace is running */
        if (ftrace_start_up) {
                command = FTRACE_DISABLE_CALLS;
                if (ftrace_graph_active)
                        command |= FTRACE_STOP_FUNC_RET;
                ftrace_run_update_code(command);
        }
}

static u64              ftrace_update_time;
unsigned long           ftrace_update_tot_cnt;
unsigned long           ftrace_number_of_pages;
unsigned long           ftrace_number_of_groups;

static inline int ops_traces_mod(struct ftrace_ops *ops)
{
        /*
         * Filter_hash being empty will default to trace module.
         * But notrace hash requires a test of individual module functions.
         */
        return ftrace_hash_empty(ops->func_hash->filter_hash) &&
                ftrace_hash_empty(ops->func_hash->notrace_hash);
}

/*
 * Check if the current ops references the record.
 *
 * If the ops traces all functions, then it was already accounted for.
 * If the ops does not trace the current record function, skip it.
 * If the ops ignores the function via notrace filter, skip it.
 */
static inline bool
ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
{
        /* If ops isn't enabled, ignore it */
        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
                return false;

        /* If ops traces all then it includes this function */
        if (ops_traces_mod(ops))
                return true;

        /* The function must be in the filter */
        if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
            !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
                return false;

        /* If in notrace hash, we ignore it too */
        if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
                return false;

        return true;
}

static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
{
        struct ftrace_page *pg;
        struct dyn_ftrace *p;
        u64 start, stop;
        unsigned long update_cnt = 0;
        unsigned long rec_flags = 0;
        int i;

        start = ftrace_now(raw_smp_processor_id());

        /*
         * When a module is loaded, this function is called to convert
         * the calls to mcount in its text to nops, and also to create
         * an entry in the ftrace data. Now, if ftrace is activated
         * after this call, but before the module sets its text to
         * read-only, the modification of enabling ftrace can fail if
         * the read-only is done while ftrace is converting the calls.
         * To prevent this, the module's records are set as disabled
         * and will be enabled after the call to set the module's text
         * to read-only.
         */
        if (mod)
                rec_flags |= FTRACE_FL_DISABLED;

        for (pg = new_pgs; pg; pg = pg->next) {

                for (i = 0; i < pg->index; i++) {

                        /* If something went wrong, bail without enabling anything */
                        if (unlikely(ftrace_disabled))
                                return -1;

                        p = &pg->records[i];
                        p->flags = rec_flags;

                        /*
                         * Do the initial record conversion from mcount jump
                         * to the NOP instructions.
                         */
                        if (!__is_defined(CC_USING_NOP_MCOUNT) &&
                            !ftrace_nop_initialize(mod, p))
                                break;

                        update_cnt++;
                }
        }

        stop = ftrace_now(raw_smp_processor_id());
        ftrace_update_time = stop - start;
        ftrace_update_tot_cnt += update_cnt;

        return 0;
}

static int ftrace_allocate_records(struct ftrace_page *pg, int count)
{
        int order;
        int pages;
        int cnt;

        if (WARN_ON(!count))
                return -EINVAL;

        /* We want to fill as much as possible, with no empty pages */
        pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
        order = fls(pages) - 1;

 again:
        pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);

        if (!pg->records) {
                /* if we can't allocate this size, try something smaller */
                if (!order)
                        return -ENOMEM;
                order >>= 1;
                goto again;
        }

        ftrace_number_of_pages += 1 << order;
        ftrace_number_of_groups++;

        cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
        pg->order = order;

        if (cnt > count)
                cnt = count;

        return cnt;
}

static struct ftrace_page *
ftrace_allocate_pages(unsigned long num_to_init)
{
        struct ftrace_page *start_pg;
        struct ftrace_page *pg;
        int cnt;

        if (!num_to_init)
                return NULL;

        start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
        if (!pg)
                return NULL;

        /*
         * Try to allocate as much as possible in one continues
         * location that fills in all of the space. We want to
         * waste as little space as possible.
         */
        for (;;) {
                cnt = ftrace_allocate_records(pg, num_to_init);
                if (cnt < 0)
                        goto free_pages;

                num_to_init -= cnt;
                if (!num_to_init)
                        break;

                pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
                if (!pg->next)
                        goto free_pages;

                pg = pg->next;
        }

        return start_pg;

 free_pages:
        pg = start_pg;
        while (pg) {
                if (pg->records) {
                        free_pages((unsigned long)pg->records, pg->order);
                        ftrace_number_of_pages -= 1 << pg->order;
                }
                start_pg = pg->next;
                kfree(pg);
                pg = start_pg;
                ftrace_number_of_groups--;
        }
        pr_info("ftrace: FAILED to allocate memory for functions\n");
        return NULL;
}

#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */

struct ftrace_iterator {
        loff_t                          pos;
        loff_t                          func_pos;
        loff_t                          mod_pos;
        struct ftrace_page              *pg;
        struct dyn_ftrace               *func;
        struct ftrace_func_probe        *probe;
        struct ftrace_func_entry        *probe_entry;
        struct trace_parser             parser;
        struct ftrace_hash              *hash;
        struct ftrace_ops               *ops;
        struct trace_array              *tr;
        struct list_head                *mod_list;
        int                             pidx;
        int                             idx;
        unsigned                        flags;
};

static void *
t_probe_next(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        struct trace_array *tr = iter->ops->private;
        struct list_head *func_probes;
        struct ftrace_hash *hash;
        struct list_head *next;
        struct hlist_node *hnd = NULL;
        struct hlist_head *hhd;
        int size;

        (*pos)++;
        iter->pos = *pos;

        if (!tr)
                return NULL;

        func_probes = &tr->func_probes;
        if (list_empty(func_probes))
                return NULL;

        if (!iter->probe) {
                next = func_probes->next;
                iter->probe = list_entry(next, struct ftrace_func_probe, list);
        }

        if (iter->probe_entry)
                hnd = &iter->probe_entry->hlist;

        hash = iter->probe->ops.func_hash->filter_hash;

        /*
         * A probe being registered may temporarily have an empty hash
         * and it's at the end of the func_probes list.
         */
        if (!hash || hash == EMPTY_HASH)
                return NULL;

        size = 1 << hash->size_bits;

 retry:
        if (iter->pidx >= size) {
                if (iter->probe->list.next == func_probes)
                        return NULL;
                next = iter->probe->list.next;
                iter->probe = list_entry(next, struct ftrace_func_probe, list);
                hash = iter->probe->ops.func_hash->filter_hash;
                size = 1 << hash->size_bits;
                iter->pidx = 0;
        }

        hhd = &hash->buckets[iter->pidx];

        if (hlist_empty(hhd)) {
                iter->pidx++;
                hnd = NULL;
                goto retry;
        }

        if (!hnd)
                hnd = hhd->first;
        else {
                hnd = hnd->next;
                if (!hnd) {
                        iter->pidx++;
                        goto retry;
                }
        }

        if (WARN_ON_ONCE(!hnd))
                return NULL;

        iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);

        return iter;
}

static void *t_probe_start(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        void *p = NULL;
        loff_t l;

        if (!(iter->flags & FTRACE_ITER_DO_PROBES))
                return NULL;

        if (iter->mod_pos > *pos)
                return NULL;

        iter->probe = NULL;
        iter->probe_entry = NULL;
        iter->pidx = 0;
        for (l = 0; l <= (*pos - iter->mod_pos); ) {
                p = t_probe_next(m, &l);
                if (!p)
                        break;
        }
        if (!p)
                return NULL;

        /* Only set this if we have an item */
        iter->flags |= FTRACE_ITER_PROBE;

        return iter;
}

static int
t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
{
        struct ftrace_func_entry *probe_entry;
        struct ftrace_probe_ops *probe_ops;
        struct ftrace_func_probe *probe;

        probe = iter->probe;
        probe_entry = iter->probe_entry;

        if (WARN_ON_ONCE(!probe || !probe_entry))
                return -EIO;

        probe_ops = probe->probe_ops;

        if (probe_ops->print)
                return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);

        seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
                   (void *)probe_ops->func);

        return 0;
}

static void *
t_mod_next(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        struct trace_array *tr = iter->tr;

        (*pos)++;
        iter->pos = *pos;

        iter->mod_list = iter->mod_list->next;

        if (iter->mod_list == &tr->mod_trace ||
            iter->mod_list == &tr->mod_notrace) {
                iter->flags &= ~FTRACE_ITER_MOD;
                return NULL;
        }

        iter->mod_pos = *pos;

        return iter;
}

static void *t_mod_start(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        void *p = NULL;
        loff_t l;

        if (iter->func_pos > *pos)
                return NULL;

        iter->mod_pos = iter->func_pos;

        /* probes are only available if tr is set */
        if (!iter->tr)
                return NULL;

        for (l = 0; l <= (*pos - iter->func_pos); ) {
                p = t_mod_next(m, &l);
                if (!p)
                        break;
        }
        if (!p) {
                iter->flags &= ~FTRACE_ITER_MOD;
                return t_probe_start(m, pos);
        }

        /* Only set this if we have an item */
        iter->flags |= FTRACE_ITER_MOD;

        return iter;
}

static int
t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
{
        struct ftrace_mod_load *ftrace_mod;
        struct trace_array *tr = iter->tr;

        if (WARN_ON_ONCE(!iter->mod_list) ||
                         iter->mod_list == &tr->mod_trace ||
                         iter->mod_list == &tr->mod_notrace)
                return -EIO;

        ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);

        if (ftrace_mod->func)
                seq_printf(m, "%s", ftrace_mod->func);
        else
                seq_putc(m, '*');

        seq_printf(m, ":mod:%s\n", ftrace_mod->module);

        return 0;
}

static void *
t_func_next(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        struct dyn_ftrace *rec = NULL;

        (*pos)++;

 retry:
        if (iter->idx >= iter->pg->index) {
                if (iter->pg->next) {
                        iter->pg = iter->pg->next;
                        iter->idx = 0;
                        goto retry;
                }
        } else {
                rec = &iter->pg->records[iter->idx++];
                if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
                     !ftrace_lookup_ip(iter->hash, rec->ip)) ||

                    ((iter->flags & FTRACE_ITER_ENABLED) &&
                     !(rec->flags & FTRACE_FL_ENABLED))) {

                        rec = NULL;
                        goto retry;
                }
        }

        if (!rec)
                return NULL;

        iter->pos = iter->func_pos = *pos;
        iter->func = rec;

        return iter;
}

static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        loff_t l = *pos; /* t_probe_start() must use original pos */
        void *ret;

        if (unlikely(ftrace_disabled))
                return NULL;

        if (iter->flags & FTRACE_ITER_PROBE)
                return t_probe_next(m, pos);

        if (iter->flags & FTRACE_ITER_MOD)
                return t_mod_next(m, pos);

        if (iter->flags & FTRACE_ITER_PRINTALL) {
                /* next must increment pos, and t_probe_start does not */
                (*pos)++;
                return t_mod_start(m, &l);
        }

        ret = t_func_next(m, pos);

        if (!ret)
                return t_mod_start(m, &l);

        return ret;
}

static void reset_iter_read(struct ftrace_iterator *iter)
{
        iter->pos = 0;
        iter->func_pos = 0;
        iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
}

static void *t_start(struct seq_file *m, loff_t *pos)
{
        struct ftrace_iterator *iter = m->private;
        void *p = NULL;
        loff_t l;

        mutex_lock(&ftrace_lock);

        if (unlikely(ftrace_disabled))
                return NULL;

        /*
         * If an lseek was done, then reset and start from beginning.
         */
        if (*pos < iter->pos)
                reset_iter_read(iter);

        /*
         * For set_ftrace_filter reading, if we have the filter
         * off, we can short cut and just print out that all
         * functions are enabled.
         */
        if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
            ftrace_hash_empty(iter->hash)) {
                iter->func_pos = 1; /* Account for the message */
                if (*pos > 0)
                        return t_mod_start(m, pos);
                iter->flags |= FTRACE_ITER_PRINTALL;
                /* reset in case of seek/pread */
                iter->flags &= ~FTRACE_ITER_PROBE;
                return iter;
        }

        if (iter->flags & FTRACE_ITER_MOD)
                return t_mod_start(m, pos);

        /*
         * Unfortunately, we need to restart at ftrace_pages_start
         * every time we let go of the ftrace_mutex. This is because
         * those pointers can change without the lock.
         */
        iter->pg = ftrace_pages_start;
        iter->idx = 0;
        for (l = 0; l <= *pos; ) {
                p = t_func_next(m, &l);
                if (!p)
                        break;
        }

        if (!p)
                return t_mod_start(m, pos);

        return iter;
}

static void t_stop(struct seq_file *m, void *p)
{
        mutex_unlock(&ftrace_lock);
}

void * __weak
arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
{
        return NULL;
}

static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
                                struct dyn_ftrace *rec)
{
        void *ptr;

        ptr = arch_ftrace_trampoline_func(ops, rec);
        if (ptr)
                seq_printf(m, " ->%pS", ptr);
}

static int t_show(struct seq_file *m, void *v)
{
        struct ftrace_iterator *iter = m->private;
        struct dyn_ftrace *rec;

        if (iter->flags & FTRACE_ITER_PROBE)
                return t_probe_show(m, iter);

        if (iter->flags & FTRACE_ITER_MOD)
                return t_mod_show(m, iter);

        if (iter->flags & FTRACE_ITER_PRINTALL) {
                if (iter->flags & FTRACE_ITER_NOTRACE)
                        seq_puts(m, "#### no functions disabled ####\n");
                else
                        seq_puts(m, "#### all functions enabled ####\n");
                return 0;
        }

        rec = iter->func;

        if (!rec)
                return 0;

        seq_printf(m, "%ps", (void *)rec->ip);
        if (iter->flags & FTRACE_ITER_ENABLED) {
                struct ftrace_ops *ops;

                seq_printf(m, " (%ld)%s%s%s",
                           ftrace_rec_count(rec),
                           rec->flags & FTRACE_FL_REGS ? " R" : "  ",
                           rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
                           rec->flags & FTRACE_FL_DIRECT ? " D" : "  ");
                if (rec->flags & FTRACE_FL_TRAMP_EN) {
                        ops = ftrace_find_tramp_ops_any(rec);
                        if (ops) {
                                do {
                                        seq_printf(m, "\ttramp: %pS (%pS)",
                                                   (void *)ops->trampoline,
                                                   (void *)ops->func);
                                        add_trampoline_func(m, ops, rec);
                                        ops = ftrace_find_tramp_ops_next(rec, ops);
                                } while (ops);
                        } else
                                seq_puts(m, "\ttramp: ERROR!");
                } else {
                        add_trampoline_func(m, NULL, rec);
                }
                if (rec->flags & FTRACE_FL_DIRECT) {
                        unsigned long direct;

                        direct = ftrace_find_rec_direct(rec->ip);
                        if (direct)
                                seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
                }
        }

        seq_putc(m, '\n');

        return 0;
}

static const struct seq_operations show_ftrace_seq_ops = {
        .start = t_start,
        .next = t_next,
        .stop = t_stop,
        .show = t_show,
};

static int
ftrace_avail_open(struct inode *inode, struct file *file)
{
        struct ftrace_iterator *iter;
        int ret;

        ret = security_locked_down(LOCKDOWN_TRACEFS);
        if (ret)
                return ret;

        if (unlikely(ftrace_disabled))
                return -ENODEV;

        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
        if (!iter)
                return -ENOMEM;

        iter->pg = ftrace_pages_start;
        iter->ops = &global_ops;

        return 0;
}

static int
ftrace_enabled_open(struct inode *inode, struct file *file)
{
        struct ftrace_iterator *iter;

        /*
         * This shows us what functions are currently being
         * traced and by what. Not sure if we want lockdown
         * to hide such critical information for an admin.
         * Although, perhaps it can show information we don't
         * want people to see, but if something is tracing
         * something, we probably want to know about it.
         */

        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
        if (!iter)
                return -ENOMEM;

        iter->pg = ftrace_pages_start;
        iter->flags = FTRACE_ITER_ENABLED;
        iter->ops = &global_ops;

        return 0;
}

/**
 * ftrace_regex_open - initialize function tracer filter files
 * @ops: The ftrace_ops that hold the hash filters
 * @flag: The type of filter to process
 * @inode: The inode, usually passed in to your open routine
 * @file: The file, usually passed in to your open routine
 *
 * ftrace_regex_open() initializes the filter files for the
 * @ops. Depending on @flag it may process the filter hash or
 * the notrace hash of @ops. With this called from the open
 * routine, you can use ftrace_filter_write() for the write
 * routine if @flag has FTRACE_ITER_FILTER set, or
 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
 * tracing_lseek() should be used as the lseek routine, and
 * release must call ftrace_regex_release().
 */
int
ftrace_regex_open(struct ftrace_ops *ops, int flag,
                  struct inode *inode, struct file *file)
{
        struct ftrace_iterator *iter;
        struct ftrace_hash *hash;
        struct list_head *mod_head;
        struct trace_array *tr = ops->private;
        int ret = -ENOMEM;

        ftrace_ops_init(ops);

        if (unlikely(ftrace_disabled))
                return -ENODEV;

        if (tracing_check_open_get_tr(tr))
                return -ENODEV;

        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
        if (!iter)
                goto out;

        if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
                goto out;

        iter->ops = ops;
        iter->flags = flag;
        iter->tr = tr;

        mutex_lock(&ops->func_hash->regex_lock);

        if (flag & FTRACE_ITER_NOTRACE) {
                hash = ops->func_hash->notrace_hash;
                mod_head = tr ? &tr->mod_notrace : NULL;
        } else {
                hash = ops->func_hash->filter_hash;
                mod_head = tr ? &tr->mod_trace : NULL;
        }

        iter->mod_list = mod_head;

        if (file->f_mode & FMODE_WRITE) {
                const int size_bits = FTRACE_HASH_DEFAULT_BITS;

                if (file->f_flags & O_TRUNC) {
                        iter->hash = alloc_ftrace_hash(size_bits);
                        clear_ftrace_mod_list(mod_head);
                } else {
                        iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
                }

                if (!iter->hash) {
                        trace_parser_put(&iter->parser);
                        goto out_unlock;
                }
        } else
                iter->hash = hash;

        ret = 0;

        if (file->f_mode & FMODE_READ) {
                iter->pg = ftrace_pages_start;

                ret = seq_open(file, &show_ftrace_seq_ops);
                if (!ret) {
                        struct seq_file *m = file->private_data;
                        m->private = iter;
                } else {
                        /* Failed */
                        free_ftrace_hash(iter->hash);
                        trace_parser_put(&iter->parser);
                }
        } else
                file->private_data = iter;

 out_unlock:
        mutex_unlock(&ops->func_hash->regex_lock);

 out:
        if (ret) {
                kfree(iter);
                if (tr)
                        trace_array_put(tr);
        }

        return ret;
}

static int
ftrace_filter_open(struct inode *inode, struct file *file)
{
        struct ftrace_ops *ops = inode->i_private;

        /* Checks for tracefs lockdown */
        return ftrace_regex_open(ops,
                        FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
                        inode, file);
}

static int
ftrace_notrace_open(struct inode *inode, struct file *file)
{
        struct ftrace_ops *ops = inode->i_private;

        /* Checks for tracefs lockdown */
        return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
                                 inode, file);
}

/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
struct ftrace_glob {
        char *search;
        unsigned len;
        int type;
};

/*
 * If symbols in an architecture don't correspond exactly to the user-visible
 * name of what they represent, it is possible to define this function to
 * perform the necessary adjustments.
*/
char * __weak arch_ftrace_match_adjust(char *str, const char *search)
{
        return str;
}

static int ftrace_match(char *str, struct ftrace_glob *g)
{
        int matched = 0;
        int slen;

        str = arch_ftrace_match_adjust(str, g->search);

        switch (g->type) {
        case MATCH_FULL:
                if (strcmp(str, g->search) == 0)
                        matched = 1;
                break;
        case MATCH_FRONT_ONLY:
                if (strncmp(str, g->search, g->len) == 0)
                        matched = 1;
                break;
        case MATCH_MIDDLE_ONLY:
                if (strstr(str, g->search))
                        matched = 1;
                break;
        case MATCH_END_ONLY:
                slen = strlen(str);
                if (slen >= g->len &&
                    memcmp(str + slen - g->len, g->search, g->len) == 0)
                        matched = 1;
                break;
        case MATCH_GLOB:
                if (glob_match(g->search, str))
                        matched = 1;
                break;
        }

        return matched;
}

static int
enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
{
        struct ftrace_func_entry *entry;
        int ret = 0;

        entry = ftrace_lookup_ip(hash, rec->ip);
        if (clear_filter) {
                /* Do nothing if it doesn't exist */
                if (!entry)
                        return 0;

                free_hash_entry(hash, entry);
        } else {
                /* Do nothing if it exists */
                if (entry)
                        return 0;

                ret = add_hash_entry(hash, rec->ip);
        }
        return ret;
}

static int
add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
                 int clear_filter)
{
        long index = simple_strtoul(func_g->search, NULL, 0);
        struct ftrace_page *pg;
        struct dyn_ftrace *rec;

        /* The index starts at 1 */
        if (--index < 0)
                return 0;

        do_for_each_ftrace_rec(pg, rec) {
                if (pg->index <= index) {
                        index -= pg->index;
                        /* this is a double loop, break goes to the next page */
                        break;
                }
                rec = &pg->records[index];
                enter_record(hash, rec, clear_filter);
                return 1;
        } while_for_each_ftrace_rec();
        return 0;
}

static int
ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
                struct ftrace_glob *mod_g, int exclude_mod)
{
        char str[KSYM_SYMBOL_LEN];
        char *modname;

        kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);

        if (mod_g) {
                int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;

                /* blank module name to match all modules */
                if (!mod_g->len) {
                        /* blank module globbing: modname xor exclude_mod */
                        if (!exclude_mod != !modname)
                                goto func_match;
                        return 0;
                }

                /*
                 * exclude_mod is set to trace everything but the given
                 * module. If it is set and the module matches, then
                 * return 0. If it is not set, and the module doesn't match
                 * also return 0. Otherwise, check the function to see if
                 * that matches.
                 */
                if (!mod_matches == !exclude_mod)
                        return 0;
func_match:
                /* blank search means to match all funcs in the mod */
                if (!func_g->len)
                        return 1;
        }

        return ftrace_match(str, func_g);
}