jitdump.c

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// SPDX-License-Identifier: GPL-2.0
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <inttypes.h>
#include <byteswap.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <linux/stringify.h>

#include "util.h"
#include "event.h"
#include "debug.h"
#include "evlist.h"
#include "symbol.h"
#include <elf.h>

#include "tsc.h"
#include "session.h"
#include "jit.h"
#include "jitdump.h"
#include "genelf.h"
#include "../builtin.h"

#include "sane_ctype.h"

struct jit_buf_desc {
    struct perf_data *output;
    struct perf_session *session;
    struct machine *machine;
    union jr_entry   *entry;
    void             *buf;
    uint64_t     sample_type;
    size_t           bufsize;
    FILE             *in;
    bool         needs_bswap; /* handles cross-endianess */
    bool         use_arch_timestamp;
    void         *debug_data;
    void         *unwinding_data;
    uint64_t     unwinding_size;
    uint64_t     unwinding_mapped_size;
    uint64_t         eh_frame_hdr_size;
    size_t       nr_debug_entries;
    uint32_t         code_load_count;
    u64      bytes_written;
    struct rb_root   code_root;
    char         dir[PATH_MAX];
};

struct debug_line_info {
    unsigned long vma;
    unsigned int lineno;
    /* The filename format is unspecified, absolute path, relative etc. */
    char const filename[0];
};

struct jit_tool {
    struct perf_tool tool;
    struct perf_data    output;
    struct perf_data    input;
    u64 bytes_written;
};

#define hmax(a, b) ((a) > (b) ? (a) : (b))
#define get_jit_tool(t) (container_of(tool, struct jit_tool, tool))

static int
jit_emit_elf(char *filename,
         const char *sym,
         uint64_t code_addr,
         const void *code,
         int csize,
         void *debug,
         int nr_debug_entries,
         void *unwinding,
         uint32_t unwinding_header_size,
         uint32_t unwinding_size)
{
    int ret, fd;

    if (verbose > 0)
        fprintf(stderr, "write ELF image %s\n", filename);

    fd = open(filename, O_CREAT|O_TRUNC|O_WRONLY, 0644);
    if (fd == -1) {
        pr_warning("cannot create jit ELF %s: %s\n", filename, strerror(errno));
        return -1;
    }

    ret = jit_write_elf(fd, code_addr, sym, (const void *)code, csize, debug, nr_debug_entries,
                unwinding, unwinding_header_size, unwinding_size);

        close(fd);

        if (ret)
                unlink(filename);

    return ret;
}

static void
jit_close(struct jit_buf_desc *jd)
{
    if (!(jd && jd->in))
        return;
    funlockfile(jd->in);
    fclose(jd->in);
    jd->in = NULL;
}

static int
jit_validate_events(struct perf_session *session)
{
    struct perf_evsel *evsel;

    /*
     * check that all events use CLOCK_MONOTONIC
     */
    evlist__for_each_entry(session->evlist, evsel) {
        if (evsel->attr.use_clockid == 0 || evsel->attr.clockid != CLOCK_MONOTONIC)
            return -1;
    }
    return 0;
}

static int
jit_open(struct jit_buf_desc *jd, const char *name)
{
    struct jitheader header;
    struct jr_prefix *prefix;
    ssize_t bs, bsz = 0;
    void *n, *buf = NULL;
    int ret, retval = -1;

    jd->in = fopen(name, "r");
    if (!jd->in)
        return -1;

    bsz = hmax(sizeof(header), sizeof(*prefix));

    buf = malloc(bsz);
    if (!buf)
        goto error;

    /*
     * protect from writer modifying the file while we are reading it
     */
    flockfile(jd->in);

    ret = fread(buf, sizeof(header), 1, jd->in);
    if (ret != 1)
        goto error;

    memcpy(&header, buf, sizeof(header));

    if (header.magic != JITHEADER_MAGIC) {
        if (header.magic != JITHEADER_MAGIC_SW)
            goto error;
        jd->needs_bswap = true;
    }

    if (jd->needs_bswap) {
        header.version    = bswap_32(header.version);
        header.total_size = bswap_32(header.total_size);
        header.pid    = bswap_32(header.pid);
        header.elf_mach   = bswap_32(header.elf_mach);
        header.timestamp  = bswap_64(header.timestamp);
        header.flags      = bswap_64(header.flags);
    }

    jd->use_arch_timestamp = header.flags & JITDUMP_FLAGS_ARCH_TIMESTAMP;

    if (verbose > 2)
        pr_debug("version=%u\nhdr.size=%u\nts=0x%llx\npid=%d\nelf_mach=%d\nuse_arch_timestamp=%d\n",
            header.version,
            header.total_size,
            (unsigned long long)header.timestamp,
            header.pid,
            header.elf_mach,
            jd->use_arch_timestamp);

    if (header.version > JITHEADER_VERSION) {
        pr_err("wrong jitdump version %u, expected " __stringify(JITHEADER_VERSION),
            header.version);
        goto error;
    }

    if (header.flags & JITDUMP_FLAGS_RESERVED) {
        pr_err("jitdump file contains invalid or unsupported flags 0x%llx\n",
               (unsigned long long)header.flags & JITDUMP_FLAGS_RESERVED);
        goto error;
    }

    if (jd->use_arch_timestamp && !jd->session->time_conv.time_mult) {
        pr_err("jitdump file uses arch timestamps but there is no timestamp conversion\n");
        goto error;
    }

    /*
     * validate event is using the correct clockid
     */
    if (!jd->use_arch_timestamp && jit_validate_events(jd->session)) {
        pr_err("error, jitted code must be sampled with perf record -k 1\n");
        goto error;
    }

    bs = header.total_size - sizeof(header);

    if (bs > bsz) {
        n = realloc(buf, bs);
        if (!n)
            goto error;
        bsz = bs;
        buf = n;
        /* read extra we do not know about */
        ret = fread(buf, bs - bsz, 1, jd->in);
        if (ret != 1)
            goto error;
    }
    /*
     * keep dirname for generating files and mmap records
     */
    strcpy(jd->dir, name);
    dirname(jd->dir);

    return 0;
error:
    funlockfile(jd->in);
    fclose(jd->in);
    return retval;
}

static union jr_entry *
jit_get_next_entry(struct jit_buf_desc *jd)
{
    struct jr_prefix *prefix;
    union jr_entry *jr;
    void *addr;
    size_t bs, size;
    int id, ret;

    if (!(jd && jd->in))
        return NULL;

    if (jd->buf == NULL) {
        size_t sz = getpagesize();
        if (sz < sizeof(*prefix))
            sz = sizeof(*prefix);

        jd->buf = malloc(sz);
        if (jd->buf == NULL)
            return NULL;

        jd->bufsize = sz;
    }

    prefix = jd->buf;

    /*
     * file is still locked at this point
     */
    ret = fread(prefix, sizeof(*prefix), 1, jd->in);
    if (ret  != 1)
        return NULL;

    if (jd->needs_bswap) {
        prefix->id         = bswap_32(prefix->id);
        prefix->total_size = bswap_32(prefix->total_size);
        prefix->timestamp  = bswap_64(prefix->timestamp);
    }
    id   = prefix->id;
    size = prefix->total_size;

    bs = (size_t)size;
    if (bs < sizeof(*prefix))
        return NULL;

    if (id >= JIT_CODE_MAX) {
        pr_warning("next_entry: unknown record type %d, skipping\n", id);
    }
    if (bs > jd->bufsize) {
        void *n;
        n = realloc(jd->buf, bs);
        if (!n)
            return NULL;
        jd->buf = n;
        jd->bufsize = bs;
    }

    addr = ((void *)jd->buf) + sizeof(*prefix);

    ret = fread(addr, bs - sizeof(*prefix), 1, jd->in);
    if (ret != 1)
        return NULL;

    jr = (union jr_entry *)jd->buf;

    switch(id) {
    case JIT_CODE_DEBUG_INFO:
        if (jd->needs_bswap) {
            uint64_t n;
            jr->info.code_addr = bswap_64(jr->info.code_addr);
            jr->info.nr_entry  = bswap_64(jr->info.nr_entry);
            for (n = 0 ; n < jr->info.nr_entry; n++) {
                jr->info.entries[n].addr    = bswap_64(jr->info.entries[n].addr);
                jr->info.entries[n].lineno  = bswap_32(jr->info.entries[n].lineno);
                jr->info.entries[n].discrim = bswap_32(jr->info.entries[n].discrim);
            }
        }
        break;
    case JIT_CODE_UNWINDING_INFO:
        if (jd->needs_bswap) {
            jr->unwinding.unwinding_size = bswap_64(jr->unwinding.unwinding_size);
            jr->unwinding.eh_frame_hdr_size = bswap_64(jr->unwinding.eh_frame_hdr_size);
            jr->unwinding.mapped_size = bswap_64(jr->unwinding.mapped_size);
        }
        break;
    case JIT_CODE_CLOSE:
        break;
    case JIT_CODE_LOAD:
        if (jd->needs_bswap) {
            jr->load.pid       = bswap_32(jr->load.pid);
            jr->load.tid       = bswap_32(jr->load.tid);
            jr->load.vma       = bswap_64(jr->load.vma);
            jr->load.code_addr = bswap_64(jr->load.code_addr);
            jr->load.code_size = bswap_64(jr->load.code_size);
            jr->load.code_index= bswap_64(jr->load.code_index);
        }
        jd->code_load_count++;
        break;
    case JIT_CODE_MOVE:
        if (jd->needs_bswap) {
            jr->move.pid           = bswap_32(jr->move.pid);
            jr->move.tid           = bswap_32(jr->move.tid);
            jr->move.vma           = bswap_64(jr->move.vma);
            jr->move.old_code_addr = bswap_64(jr->move.old_code_addr);
            jr->move.new_code_addr = bswap_64(jr->move.new_code_addr);
            jr->move.code_size     = bswap_64(jr->move.code_size);
            jr->move.code_index    = bswap_64(jr->move.code_index);
        }
        break;
    case JIT_CODE_MAX:
    default:
        /* skip unknown record (we have read them) */
        break;
    }
    return jr;
}

static int
jit_inject_event(struct jit_buf_desc *jd, union perf_event *event)
{
    ssize_t size;

    size = perf_data__write(jd->output, event, event->header.size);
    if (size < 0)
        return -1;

    jd->bytes_written += size;
    return 0;
}

static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
{
    struct perf_tsc_conversion tc;

    if (!jd->use_arch_timestamp)
        return timestamp;

    tc.time_shift = jd->session->time_conv.time_shift;
    tc.time_mult  = jd->session->time_conv.time_mult;
    tc.time_zero  = jd->session->time_conv.time_zero;

    if (!tc.time_mult)
        return 0;

    return tsc_to_perf_time(timestamp, &tc);
}

static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
{
    struct perf_sample sample;
    union perf_event *event;
    struct perf_tool *tool = jd->session->tool;
    uint64_t code, addr;
    uintptr_t uaddr;
    char *filename;
    struct stat st;
    size_t size;
    u16 idr_size;
    const char *sym;
    uint32_t count;
    int ret, csize, usize;
    pid_t pid, tid;
    struct {
        u32 pid, tid;
        u64 time;
    } *id;

    pid   = jr->load.pid;
    tid   = jr->load.tid;
    csize = jr->load.code_size;
    usize = jd->unwinding_mapped_size;
    addr  = jr->load.code_addr;
    sym   = (void *)((unsigned long)jr + sizeof(jr->load));
    code  = (unsigned long)jr + jr->load.p.total_size - csize;
    count = jr->load.code_index;
    idr_size = jd->machine->id_hdr_size;

    event = calloc(1, sizeof(*event) + idr_size);
    if (!event)
        return -1;

    filename = event->mmap2.filename;
    size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%u.so",
            jd->dir,
            pid,
            count);

    size++; /* for \0 */

    size = PERF_ALIGN(size, sizeof(u64));
    uaddr = (uintptr_t)code;
    ret = jit_emit_elf(filename, sym, addr, (const void *)uaddr, csize, jd->debug_data, jd->nr_debug_entries,
               jd->unwinding_data, jd->eh_frame_hdr_size, jd->unwinding_size);

    if (jd->debug_data && jd->nr_debug_entries) {
        free(jd->debug_data);
        jd->debug_data = NULL;
        jd->nr_debug_entries = 0;
    }

    if (jd->unwinding_data && jd->eh_frame_hdr_size) {
        free(jd->unwinding_data);
        jd->unwinding_data = NULL;
        jd->eh_frame_hdr_size = 0;
        jd->unwinding_mapped_size = 0;
        jd->unwinding_size = 0;
    }

    if (ret) {
        free(event);
        return -1;
    }
    if (stat(filename, &st))
        memset(&st, 0, sizeof(st));

    event->mmap2.header.type = PERF_RECORD_MMAP2;
    event->mmap2.header.misc = PERF_RECORD_MISC_USER;
    event->mmap2.header.size = (sizeof(event->mmap2) -
            (sizeof(event->mmap2.filename) - size) + idr_size);

    event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
    event->mmap2.start = addr;
    event->mmap2.len   = usize ? ALIGN_8(csize) + usize : csize;
    event->mmap2.pid   = pid;
    event->mmap2.tid   = tid;
    event->mmap2.ino   = st.st_ino;
    event->mmap2.maj   = major(st.st_dev);
    event->mmap2.min   = minor(st.st_dev);
    event->mmap2.prot  = st.st_mode;
    event->mmap2.flags = MAP_SHARED;
    event->mmap2.ino_generation = 1;

    id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
    if (jd->sample_type & PERF_SAMPLE_TID) {
        id->pid  = pid;
        id->tid  = tid;
    }
    if (jd->sample_type & PERF_SAMPLE_TIME)
        id->time = convert_timestamp(jd, jr->load.p.timestamp);

    /*
     * create pseudo sample to induce dso hit increment
     * use first address as sample address
     */
    memset(&sample, 0, sizeof(sample));
    sample.cpumode = PERF_RECORD_MISC_USER;
    sample.pid  = pid;
    sample.tid  = tid;
    sample.time = id->time;
    sample.ip   = addr;

    ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
    if (ret)
        return ret;

    ret = jit_inject_event(jd, event);
    /*
     * mark dso as use to generate buildid in the header
     */
    if (!ret)
        build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);

    return ret;
}

static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
{
    struct perf_sample sample;
    union perf_event *event;
    struct perf_tool *tool = jd->session->tool;
    char *filename;
    size_t size;
    struct stat st;
    int usize;
    u16 idr_size;
    int ret;
    pid_t pid, tid;
    struct {
        u32 pid, tid;
        u64 time;
    } *id;

    pid = jr->move.pid;
    tid =  jr->move.tid;
    usize = jd->unwinding_mapped_size;
    idr_size = jd->machine->id_hdr_size;

    /*
     * +16 to account for sample_id_all (hack)
     */
    event = calloc(1, sizeof(*event) + 16);
    if (!event)
        return -1;

    filename = event->mmap2.filename;
    size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%"PRIu64,
             jd->dir,
             pid,
         jr->move.code_index);

    size++; /* for \0 */

    if (stat(filename, &st))
        memset(&st, 0, sizeof(st));

    size = PERF_ALIGN(size, sizeof(u64));

    event->mmap2.header.type = PERF_RECORD_MMAP2;
    event->mmap2.header.misc = PERF_RECORD_MISC_USER;
    event->mmap2.header.size = (sizeof(event->mmap2) -
            (sizeof(event->mmap2.filename) - size) + idr_size);
    event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
    event->mmap2.start = jr->move.new_code_addr;
    event->mmap2.len   = usize ? ALIGN_8(jr->move.code_size) + usize
                   : jr->move.code_size;
    event->mmap2.pid   = pid;
    event->mmap2.tid   = tid;
    event->mmap2.ino   = st.st_ino;
    event->mmap2.maj   = major(st.st_dev);
    event->mmap2.min   = minor(st.st_dev);
    event->mmap2.prot  = st.st_mode;
    event->mmap2.flags = MAP_SHARED;
    event->mmap2.ino_generation = 1;

    id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
    if (jd->sample_type & PERF_SAMPLE_TID) {
        id->pid  = pid;
        id->tid  = tid;
    }
    if (jd->sample_type & PERF_SAMPLE_TIME)
        id->time = convert_timestamp(jd, jr->load.p.timestamp);

    /*
     * create pseudo sample to induce dso hit increment
     * use first address as sample address
     */
    memset(&sample, 0, sizeof(sample));
    sample.cpumode = PERF_RECORD_MISC_USER;
    sample.pid  = pid;
    sample.tid  = tid;
    sample.time = id->time;
    sample.ip   = jr->move.new_code_addr;

    ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
    if (ret)
        return ret;

    ret = jit_inject_event(jd, event);
    if (!ret)
        build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);

    return ret;
}

static int jit_repipe_debug_info(struct jit_buf_desc *jd, union jr_entry *jr)
{
    void *data;
    size_t sz;

    if (!(jd && jr))
        return -1;

    sz  = jr->prefix.total_size - sizeof(jr->info);
    data = malloc(sz);
    if (!data)
        return -1;

    memcpy(data, &jr->info.entries, sz);

    jd->debug_data       = data;

    /*
     * we must use nr_entry instead of size here because
     * we cannot distinguish actual entry from padding otherwise
     */
    jd->nr_debug_entries = jr->info.nr_entry;

    return 0;
}

static int
jit_repipe_unwinding_info(struct jit_buf_desc *jd, union jr_entry *jr)
{
    void *unwinding_data;
    uint32_t unwinding_data_size;

    if (!(jd && jr))
        return -1;

    unwinding_data_size  = jr->prefix.total_size - sizeof(jr->unwinding);
    unwinding_data = malloc(unwinding_data_size);
    if (!unwinding_data)
        return -1;

    memcpy(unwinding_data, &jr->unwinding.unwinding_data,
           unwinding_data_size);

    jd->eh_frame_hdr_size = jr->unwinding.eh_frame_hdr_size;
    jd->unwinding_size = jr->unwinding.unwinding_size;
    jd->unwinding_mapped_size = jr->unwinding.mapped_size;
    jd->unwinding_data = unwinding_data;

    return 0;
}

static int
jit_process_dump(struct jit_buf_desc *jd)
{
    union jr_entry *jr;
    int ret = 0;

    while ((jr = jit_get_next_entry(jd))) {
        switch(jr->prefix.id) {
        case JIT_CODE_LOAD:
            ret = jit_repipe_code_load(jd, jr);
            break;
        case JIT_CODE_MOVE:
            ret = jit_repipe_code_move(jd, jr);
            break;
        case JIT_CODE_DEBUG_INFO:
            ret = jit_repipe_debug_info(jd, jr);
            break;
        case JIT_CODE_UNWINDING_INFO:
            ret = jit_repipe_unwinding_info(jd, jr);
            break;
        default:
            ret = 0;
            continue;
        }
    }
    return ret;
}

static int
jit_inject(struct jit_buf_desc *jd, char *path)
{
    int ret;

    if (verbose > 0)
        fprintf(stderr, "injecting: %s\n", path);

    ret = jit_open(jd, path);
    if (ret)
        return -1;

    ret = jit_process_dump(jd);

    jit_close(jd);

    if (verbose > 0)
        fprintf(stderr, "injected: %s (%d)\n", path, ret);

    return 0;
}

/*
 * File must be with pattern .../jit-XXXX.dump
 * where XXXX is the PID of the process which did the mmap()
 * as captured in the RECORD_MMAP record
 */
static int
jit_detect(char *mmap_name, pid_t pid)
 {
    char *p;
    char *end = NULL;
    pid_t pid2;

    if (verbose > 2)
        fprintf(stderr, "jit marker trying : %s\n", mmap_name);
    /*
     * get file name
     */
    p = strrchr(mmap_name, '/');
    if (!p)
        return -1;

    /*
     * match prefix
     */
    if (strncmp(p, "/jit-", 5))
        return -1;

    /*
     * skip prefix
     */
    p += 5;

    /*
     * must be followed by a pid
     */
    if (!isdigit(*p))
        return -1;

    pid2 = (int)strtol(p, &end, 10);
    if (!end)
        return -1;

    /*
     * pid does not match mmap pid
     * pid==0 in system-wide mode (synthesized)
     */
    if (pid && pid2 != pid)
        return -1;
    /*
     * validate suffix
     */
    if (strcmp(end, ".dump"))
        return -1;

    if (verbose > 0)
        fprintf(stderr, "jit marker found: %s\n", mmap_name);

    return 0;
}

int
jit_process(struct perf_session *session,
        struct perf_data *output,
        struct machine *machine,
        char *filename,
        pid_t pid,
        u64 *nbytes)
{
    struct perf_evsel *first;
    struct jit_buf_desc jd;
    int ret;

    /*
     * first, detect marker mmap (i.e., the jitdump mmap)
     */
    if (jit_detect(filename, pid))
        return 0;

    memset(&jd, 0, sizeof(jd));

    jd.session = session;
    jd.output  = output;
    jd.machine = machine;

    /*
     * track sample_type to compute id_all layout
     * perf sets the same sample type to all events as of now
     */
    first = perf_evlist__first(session->evlist);
    jd.sample_type = first->attr.sample_type;

    *nbytes = 0;

    ret = jit_inject(&jd, filename);
    if (!ret) {
        *nbytes = jd.bytes_written;
        ret = 1;
    }

    return ret;
}