// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2012 The Chromium OS Authors.
 */

#include <common.h>
#include <mapmem.h>
#include <time.h>
#include <trace.h>
#include <asm/io.h>
#include <asm/sections.h>

DECLARE_GLOBAL_DATA_PTR;

static char trace_enabled __attribute__((section(".data")));
static char trace_inited __attribute__((section(".data")));

/* The header block at the start of the trace memory area */
struct trace_hdr {
        int func_count;         /* Total number of function call sites */
        u64 call_count;         /* Total number of tracked function calls */
        u64 untracked_count;    /* Total number of untracked function calls */
        int funcs_used;         /* Total number of functions used */

        /*
         * Call count for each function. This is indexed by the word offset
         * of the function from gd->relocaddr
         */
        uintptr_t *call_accum;

        /* Function trace list */
        struct trace_call *ftrace;      /* The function call records */
        ulong ftrace_size;      /* Num. of ftrace records we have space for */
        ulong ftrace_count;     /* Num. of ftrace records written */
        ulong ftrace_too_deep_count;    /* Functions that were too deep */

        int depth;
        int depth_limit;
        int max_depth;
};

static struct trace_hdr *hdr;   /* Pointer to start of trace buffer */

static inline uintptr_t __attribute__((no_instrument_function))
                func_ptr_to_num(void *func_ptr)
{
        uintptr_t offset = (uintptr_t)func_ptr;

#ifdef CONFIG_SANDBOX
        offset -= (uintptr_t)&_init;
#else
        if (gd->flags & GD_FLG_RELOC)
                offset -= gd->relocaddr;
        else
                offset -= CONFIG_SYS_TEXT_BASE;
#endif
        return offset / FUNC_SITE_SIZE;
}

#ifdef CONFIG_EFI_LOADER

/**
 * trace_gd - the value of the gd register
 */
static volatile void *trace_gd;

/**
 * trace_save_gd() - save the value of the gd register
 */
static void __attribute__((no_instrument_function)) trace_save_gd(void)
{
        trace_gd = gd;
}

/**
 * trace_swap_gd() - swap between U-Boot and application gd register value
 *
 * An UEFI application may change the value of the register that gd lives in.
 * But some of our functions like get_ticks() access this register. So we
 * have to set the gd register to the U-Boot value when entering a trace
 * point and set it back to the application value when exiting the trace point.
 */
static void __attribute__((no_instrument_function)) trace_swap_gd(void)
{
        volatile void *temp_gd = trace_gd;

        trace_gd = gd;
        gd = temp_gd;
}

#else

static void __attribute__((no_instrument_function)) trace_save_gd(void)
{
}

static void __attribute__((no_instrument_function)) trace_swap_gd(void)
{
}

#endif

static void __attribute__((no_instrument_function)) add_ftrace(void *func_ptr,
                                void *caller, ulong flags)
{
        if (hdr->depth > hdr->depth_limit) {
                hdr->ftrace_too_deep_count++;
                return;
        }
        if (hdr->ftrace_count < hdr->ftrace_size) {
                struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];

                rec->func = func_ptr_to_num(func_ptr);
                rec->caller = func_ptr_to_num(caller);
                rec->flags = flags | (timer_get_us() & FUNCF_TIMESTAMP_MASK);
        }
        hdr->ftrace_count++;
}

static void __attribute__((no_instrument_function)) add_textbase(void)
{
        if (hdr->ftrace_count < hdr->ftrace_size) {
                struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];

                rec->func = CONFIG_SYS_TEXT_BASE;
                rec->caller = 0;
                rec->flags = FUNCF_TEXTBASE;
        }
        hdr->ftrace_count++;
}

/**
 * This is called on every function entry
 *
 * We add to our tally for this function and add to the list of called
 * functions.
 *
 * @param func_ptr      Pointer to function being entered
 * @param caller        Pointer to function which called this function
 */
void __attribute__((no_instrument_function)) __cyg_profile_func_enter(
                void *func_ptr, void *caller)
{
        if (trace_enabled) {
                int func;

                trace_swap_gd();
                add_ftrace(func_ptr, caller, FUNCF_ENTRY);
                func = func_ptr_to_num(func_ptr);
                if (func < hdr->func_count) {
                        hdr->call_accum[func]++;
                        hdr->call_count++;
                } else {
                        hdr->untracked_count++;
                }
                hdr->depth++;
                if (hdr->depth > hdr->depth_limit)
                        hdr->max_depth = hdr->depth;
                trace_swap_gd();
        }
}

/**
 * This is called on every function exit
 *
 * We do nothing here.
 *
 * @param func_ptr      Pointer to function being entered
 * @param caller        Pointer to function which called this function
 */
void __attribute__((no_instrument_function)) __cyg_profile_func_exit(
                void *func_ptr, void *caller)
{
        if (trace_enabled) {
                trace_swap_gd();
                add_ftrace(func_ptr, caller, FUNCF_EXIT);
                hdr->depth--;
                trace_swap_gd();
        }
}

/**
 * Produce a list of called functions
 *
 * The information is written into the supplied buffer - a header followed
 * by a list of function records.
 *
 * @param buff          Buffer to place list into
 * @param buff_size     Size of buffer
 * @param needed        Returns size of buffer needed, which may be
 *                      greater than buff_size if we ran out of space.
 * @return 0 if ok, -1 if space was exhausted
 */
int trace_list_functions(void *buff, size_t buff_size, size_t *needed)
{
        struct trace_output_hdr *output_hdr = NULL;
        void *end, *ptr = buff;
        size_t func;
        size_t upto;

        end = buff ? buff + buff_size : NULL;

        /* Place some header information */
        if (ptr + sizeof(struct trace_output_hdr) < end)
                output_hdr = ptr;
        ptr += sizeof(struct trace_output_hdr);

        /* Add information about each function */
        for (func = upto = 0; func < hdr->func_count; func++) {
                size_t calls = hdr->call_accum[func];

                if (!calls)
                        continue;

                if (ptr + sizeof(struct trace_output_func) < end) {
                        struct trace_output_func *stats = ptr;

                        stats->offset = func * FUNC_SITE_SIZE;
                        stats->call_count = calls;
                        upto++;
                }
                ptr += sizeof(struct trace_output_func);
        }

        /* Update the header */
        if (output_hdr) {
                output_hdr->rec_count = upto;
                output_hdr->type = TRACE_CHUNK_FUNCS;
        }

        /* Work out how must of the buffer we used */
        *needed = ptr - buff;
        if (ptr > end)
                return -ENOSPC;

        return 0;
}

int trace_list_calls(void *buff, size_t buff_size, size_t *needed)
{
        struct trace_output_hdr *output_hdr = NULL;
        void *end, *ptr = buff;
        size_t rec, upto;
        size_t count;

        end = buff ? buff + buff_size : NULL;

        /* Place some header information */
        if (ptr + sizeof(struct trace_output_hdr) < end)
                output_hdr = ptr;
        ptr += sizeof(struct trace_output_hdr);

        /* Add information about each call */
        count = hdr->ftrace_count;
        if (count > hdr->ftrace_size)
                count = hdr->ftrace_size;
        for (rec = upto = 0; rec < count; rec++) {
                if (ptr + sizeof(struct trace_call) < end) {
                        struct trace_call *call = &hdr->ftrace[rec];
                        struct trace_call *out = ptr;

                        out->func = call->func * FUNC_SITE_SIZE;
                        out->caller = call->caller * FUNC_SITE_SIZE;
                        out->flags = call->flags;
                        upto++;
                }
                ptr += sizeof(struct trace_call);
        }

        /* Update the header */
        if (output_hdr) {
                output_hdr->rec_count = upto;
                output_hdr->type = TRACE_CHUNK_CALLS;
        }

        /* Work out how must of the buffer we used */
        *needed = ptr - buff;
        if (ptr > end)
                return -ENOSPC;

        return 0;
}

/* Print basic information about tracing */
void trace_print_stats(void)
{
        ulong count;

#ifndef FTRACE
        puts("Warning: make U-Boot with FTRACE to enable function instrumenting.\n");
        puts("You will likely get zeroed data here\n");
#endif
        if (!trace_inited) {
                printf("Trace is disabled\n");
                return;
        }
        print_grouped_ull(hdr->func_count, 10);
        puts(" function sites\n");
        print_grouped_ull(hdr->call_count, 10);
        puts(" function calls\n");
        print_grouped_ull(hdr->untracked_count, 10);
        puts(" untracked function calls\n");
        count = min(hdr->ftrace_count, hdr->ftrace_size);
        print_grouped_ull(count, 10);
        puts(" traced function calls");
        if (hdr->ftrace_count > hdr->ftrace_size) {
                printf(" (%lu dropped due to overflow)",
                       hdr->ftrace_count - hdr->ftrace_size);
        }
        puts("\n");
        printf("%15d maximum observed call depth\n", hdr->max_depth);
        printf("%15d call depth limit\n", hdr->depth_limit);
        print_grouped_ull(hdr->ftrace_too_deep_count, 10);
        puts(" calls not traced due to depth\n");
}

void __attribute__((no_instrument_function)) trace_set_enabled(int enabled)
{
        trace_enabled = enabled != 0;
}

/**
 * Init the tracing system ready for used, and enable it
 *
 * @param buff          Pointer to trace buffer
 * @param buff_size     Size of trace buffer
 */
int __attribute__((no_instrument_function)) trace_init(void *buff,
                size_t buff_size)
{
        ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
        size_t needed;
        int was_disabled = !trace_enabled;

        trace_save_gd();

        if (!was_disabled) {
#ifdef CONFIG_TRACE_EARLY
                char *end;
                ulong used;

                /*
                 * Copy over the early trace data if we have it. Disable
                 * tracing while we are doing this.
                 */
                trace_enabled = 0;
                hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR,
                                 CONFIG_TRACE_EARLY_SIZE);
                end = (char *)&hdr->ftrace[min(hdr->ftrace_count,
                                               hdr->ftrace_size)];
                used = end - (char *)hdr;
                printf("trace: copying %08lx bytes of early data from %x to %08lx\n",
                       used, CONFIG_TRACE_EARLY_ADDR,
                       (ulong)map_to_sysmem(buff));
                memcpy(buff, hdr, used);
#else
                puts("trace: already enabled\n");
                return -EALREADY;
#endif
        }
        hdr = (struct trace_hdr *)buff;
        needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
        if (needed > buff_size) {
                printf("trace: buffer size %zd bytes: at least %zd needed\n",
                       buff_size, needed);
                return -ENOSPC;
        }

        if (was_disabled)
                memset(hdr, '\0', needed);
        hdr->func_count = func_count;
        hdr->call_accum = (uintptr_t *)(hdr + 1);

        /* Use any remaining space for the timed function trace */
        hdr->ftrace = (struct trace_call *)(buff + needed);
        hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
        add_textbase();

        puts("trace: enabled\n");
        hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;
        trace_enabled = 1;
        trace_inited = 1;

        return 0;
}

#ifdef CONFIG_TRACE_EARLY
int __attribute__((no_instrument_function)) trace_early_init(void)
{
        ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
        size_t buff_size = CONFIG_TRACE_EARLY_SIZE;
        size_t needed;

        /* We can ignore additional calls to this function */
        if (trace_enabled)
                return 0;

        hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR, CONFIG_TRACE_EARLY_SIZE);
        needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
        if (needed > buff_size) {
                printf("trace: buffer size is %zd bytes, at least %zd needed\n",
                       buff_size, needed);
                return -ENOSPC;
        }

        memset(hdr, '\0', needed);
        hdr->call_accum = (uintptr_t *)(hdr + 1);
        hdr->func_count = func_count;

        /* Use any remaining space for the timed function trace */
        hdr->ftrace = (struct trace_call *)((char *)hdr + needed);
        hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
        add_textbase();
        hdr->depth_limit = CONFIG_TRACE_EARLY_CALL_DEPTH_LIMIT;
        printf("trace: early enable at %08x\n", CONFIG_TRACE_EARLY_ADDR);

        trace_enabled = 1;

        return 0;
}
#endif