/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/utsname.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/ftrace.h>
#include <linux/kexec.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/sysfs.h>

#include <asm/stacktrace.h>


int panic_on_unrecovered_nmi;
int panic_on_io_nmi;
unsigned int code_bytes = 64;
int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
static int die_counter;

void printk_address(unsigned long address, int reliable)
{
        pr_cont(" [<%p>] %s%pB\n",
                (void *)address, reliable ? "" : "? ", (void *)address);
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static void
print_ftrace_graph_addr(unsigned long addr, void *data,
                        const struct stacktrace_ops *ops,
                        struct thread_info *tinfo, int *graph)
{
        struct task_struct *task;
        unsigned long ret_addr;
        int index;

        if (addr != (unsigned long)return_to_handler)
                return;

        task = tinfo->task;
        index = task->curr_ret_stack;

        if (!task->ret_stack || index < *graph)
                return;

        index -= *graph;
        ret_addr = task->ret_stack[index].ret;

        ops->address(data, ret_addr, 1);

        (*graph)++;
}
#else
static inline void
print_ftrace_graph_addr(unsigned long addr, void *data,
                        const struct stacktrace_ops *ops,
                        struct thread_info *tinfo, int *graph)
{ }
#endif

/*
 * x86-64 can have up to three kernel stacks:
 * process stack
 * interrupt stack
 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
 */

static inline int valid_stack_ptr(struct thread_info *tinfo,
                        void *p, unsigned int size, void *end)
{
        void *t = tinfo;
        if (end) {
                if (p < end && p >= (end-THREAD_SIZE))
                        return 1;
                else
                        return 0;
        }
        return p > t && p < t + THREAD_SIZE - size;
}

unsigned long
print_context_stack(struct thread_info *tinfo,
                unsigned long *stack, unsigned long bp,
                const struct stacktrace_ops *ops, void *data,
                unsigned long *end, int *graph)
{
        struct stack_frame *frame = (struct stack_frame *)bp;

        while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
                unsigned long addr;

                addr = *stack;
                if (__kernel_text_address(addr)) {
                        if ((unsigned long) stack == bp + sizeof(long)) {
                                ops->address(data, addr, 1);
                                frame = frame->next_frame;
                                bp = (unsigned long) frame;
                        } else {
                                ops->address(data, addr, 0);
                        }
                        print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
                }
                stack++;
        }
        return bp;
}
EXPORT_SYMBOL_GPL(print_context_stack);

unsigned long
print_context_stack_bp(struct thread_info *tinfo,
                       unsigned long *stack, unsigned long bp,
                       const struct stacktrace_ops *ops, void *data,
                       unsigned long *end, int *graph)
{
        struct stack_frame *frame = (struct stack_frame *)bp;
        unsigned long *ret_addr = &frame->return_address;

        while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
                unsigned long addr = *ret_addr;

                if (!__kernel_text_address(addr))
                        break;

                ops->address(data, addr, 1);
                frame = frame->next_frame;
                ret_addr = &frame->return_address;
                print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
        }

        return (unsigned long)frame;
}
EXPORT_SYMBOL_GPL(print_context_stack_bp);

static int print_trace_stack(void *data, char *name)
{
        printk("%s <%s> ", (char *)data, name);
        return 0;
}

/*
 * Print one address/symbol entries per line.
 */
static void print_trace_address(void *data, unsigned long addr, int reliable)
{
        touch_nmi_watchdog();
        printk(data);
        printk_address(addr, reliable);
}

static const struct stacktrace_ops print_trace_ops = {
        .stack                  = print_trace_stack,
        .address                = print_trace_address,
        .walk_stack             = print_context_stack,
};

void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                unsigned long *stack, unsigned long bp, char *log_lvl)
{
        printk("%sCall Trace:\n", log_lvl);
        dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
}

void show_trace(struct task_struct *task, struct pt_regs *regs,
                unsigned long *stack, unsigned long bp)
{
        show_trace_log_lvl(task, regs, stack, bp, "");
}

void show_stack(struct task_struct *task, unsigned long *sp)
{
        unsigned long bp = 0;
        unsigned long stack;

        /*
         * Stack frames below this one aren't interesting.  Don't show them
         * if we're printing for %current.
         */
        if (!sp && (!task || task == current)) {
                sp = &stack;
                bp = stack_frame(current, NULL);
        }

        show_stack_log_lvl(task, NULL, sp, bp, "");
}

static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;

unsigned __kprobes long oops_begin(void)
{
        int cpu;
        unsigned long flags;

        oops_enter();

        /* racy, but better than risking deadlock. */
        raw_local_irq_save(flags);
        cpu = smp_processor_id();
        if (!arch_spin_trylock(&die_lock)) {
                if (cpu == die_owner)
                        /* nested oops. should stop eventually */;
                else
                        arch_spin_lock(&die_lock);
        }
        die_nest_count++;
        die_owner = cpu;
        console_verbose();
        bust_spinlocks(1);
        return flags;
}
EXPORT_SYMBOL_GPL(oops_begin);

void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
{
        if (regs && kexec_should_crash(current))
                crash_kexec(regs);

        bust_spinlocks(0);
        die_owner = -1;
        add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
        die_nest_count--;
        if (!die_nest_count)
                /* Nest count reaches zero, release the lock. */
                arch_spin_unlock(&die_lock);
        raw_local_irq_restore(flags);
        oops_exit();

        if (!signr)
                return;
        if (in_interrupt())
                panic("Fatal exception in interrupt");
        if (panic_on_oops)
                panic("Fatal exception");
        do_exit(signr);
}

int __kprobes __die(const char *str, struct pt_regs *regs, long err)
{
#ifdef CONFIG_X86_32
        unsigned short ss;
        unsigned long sp;
#endif
        printk(KERN_DEFAULT
               "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
        printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
        printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
        printk("DEBUG_PAGEALLOC");
#endif
        printk("\n");
        if (notify_die(DIE_OOPS, str, regs, err,
                        current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
                return 1;

        print_modules();
        show_regs(regs);
#ifdef CONFIG_X86_32
        if (user_mode_vm(regs)) {
                sp = regs->sp;
                ss = regs->ss & 0xffff;
        } else {
                sp = kernel_stack_pointer(regs);
                savesegment(ss, ss);
        }
        printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
        print_symbol("%s", regs->ip);
        printk(" SS:ESP %04x:%08lx\n", ss, sp);
#else
        /* Executive summary in case the oops scrolled away */
        printk(KERN_ALERT "RIP ");
        printk_address(regs->ip, 1);
        printk(" RSP <%016lx>\n", regs->sp);
#endif
        return 0;
}

/*
 * This is gone through when something in the kernel has done something bad
 * and is about to be terminated:
 */
void die(const char *str, struct pt_regs *regs, long err)
{
        unsigned long flags = oops_begin();
        int sig = SIGSEGV;

        if (!user_mode_vm(regs))
                report_bug(regs->ip, regs);

        if (__die(str, regs, err))
                sig = 0;
        oops_end(flags, regs, sig);
}

static int __init kstack_setup(char *s)
{
        ssize_t ret;
        unsigned long val;

        if (!s)
                return -EINVAL;

        ret = kstrtoul(s, 0, &val);
        if (ret)
                return ret;
        kstack_depth_to_print = val;
        return 0;
}
early_param("kstack", kstack_setup);

static int __init code_bytes_setup(char *s)
{
        ssize_t ret;
        unsigned long val;

        if (!s)
                return -EINVAL;

        ret = kstrtoul(s, 0, &val);
        if (ret)
                return ret;

        code_bytes = val;
        if (code_bytes > 8192)
                code_bytes = 8192;

        return 1;
}
__setup("code_bytes=", code_bytes_setup);