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accel/tcg: Move perf and debuginfo support to tcg/

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tcg/ should not depend on accel/tcg/, but perf and debuginfo
support provided by the latter are being used by tcg/tcg.c.

Since that's the only user, move both to tcg/.

Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20231212003837.64090-5-iii@linux.ibm.com>
Message-Id: <20240125054631.78867-5-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Ilya Leoshkevich 2024-01-25 06:46:30 +01:00 • committed by Richard Henderson
parent ad66ac2b3a
commit 327b75a469
13 changed files with 20 additions and 21 deletions
Download patch file Download diff file Expand all files Collapse all files

96
accel/tcg/debuginfo.c
View file

@ -1,96 +0,0 @@
/*
* Debug information support.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "qemu/lockable.h"
#include <elfutils/libdwfl.h>
#include "debuginfo.h"
static QemuMutex lock;
static Dwfl *dwfl;
static const Dwfl_Callbacks dwfl_callbacks = {
.find_elf = NULL,
.find_debuginfo = dwfl_standard_find_debuginfo,
.section_address = NULL,
.debuginfo_path = NULL,
};
__attribute__((constructor))
static void debuginfo_init(void)
{
qemu_mutex_init(&lock);
}
void debuginfo_report_elf(const char *name, int fd, uint64_t bias)
{
QEMU_LOCK_GUARD(&lock);
if (dwfl) {
dwfl_report_begin_add(dwfl);
} else {
dwfl = dwfl_begin(&dwfl_callbacks);
}
if (dwfl) {
dwfl_report_elf(dwfl, name, name, fd, bias, true);
dwfl_report_end(dwfl, NULL, NULL);
}
}
void debuginfo_lock(void)
{
qemu_mutex_lock(&lock);
}
void debuginfo_query(struct debuginfo_query *q, size_t n)
{
const char *symbol, *file;
Dwfl_Module *dwfl_module;
Dwfl_Line *dwfl_line;
GElf_Off dwfl_offset;
GElf_Sym dwfl_sym;
size_t i;
int line;
if (!dwfl) {
return;
}
for (i = 0; i < n; i++) {
dwfl_module = dwfl_addrmodule(dwfl, q[i].address);
if (!dwfl_module) {
continue;
}
if (q[i].flags & DEBUGINFO_SYMBOL) {
symbol = dwfl_module_addrinfo(dwfl_module, q[i].address,
&dwfl_offset, &dwfl_sym,
NULL, NULL, NULL);
if (symbol) {
q[i].symbol = symbol;
q[i].offset = dwfl_offset;
}
}
if (q[i].flags & DEBUGINFO_LINE) {
dwfl_line = dwfl_module_getsrc(dwfl_module, q[i].address);
if (dwfl_line) {
file = dwfl_lineinfo(dwfl_line, NULL, &line, 0, NULL, NULL);
if (file) {
q[i].file = file;
q[i].line = line;
}
}
}
}
}
void debuginfo_unlock(void)
{
qemu_mutex_unlock(&lock);
}

79
accel/tcg/debuginfo.h
View file

@ -1,79 +0,0 @@
/*
* Debug information support.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef ACCEL_TCG_DEBUGINFO_H
#define ACCEL_TCG_DEBUGINFO_H
#include "qemu/bitops.h"
/*
* Debuginfo describing a certain address.
*/
struct debuginfo_query {
uint64_t address; /* Input: address. */
int flags; /* Input: debuginfo subset. */
const char *symbol; /* Symbol that the address is part of. */
uint64_t offset; /* Offset from the symbol. */
const char *file; /* Source file associated with the address. */
int line; /* Line number in the source file. */
};
/*
* Debuginfo subsets.
*/
#define DEBUGINFO_SYMBOL BIT(1)
#define DEBUGINFO_LINE BIT(2)
#if defined(CONFIG_TCG) && defined(CONFIG_LIBDW)
/*
* Load debuginfo for the specified guest ELF image.
* Return true on success, false on failure.
*/
void debuginfo_report_elf(const char *name, int fd, uint64_t bias);
/*
* Take the debuginfo lock.
*/
void debuginfo_lock(void);
/*
* Fill each on N Qs with the debuginfo about Q->ADDRESS as specified by
* Q->FLAGS:
*
* - DEBUGINFO_SYMBOL: update Q->SYMBOL and Q->OFFSET. If symbol debuginfo is
* missing, then leave them as is.
* - DEBUINFO_LINE: update Q->FILE and Q->LINE. If line debuginfo is missing,
* then leave them as is.
*
* This function must be called under the debuginfo lock. The results can be
* accessed only until the debuginfo lock is released.
*/
void debuginfo_query(struct debuginfo_query *q, size_t n);
/*
* Release the debuginfo lock.
*/
void debuginfo_unlock(void);
#else
static inline void debuginfo_report_elf(const char *image_name, int image_fd,
uint64_t load_bias)
{
}
static inline void debuginfo_lock(void)
{
}
static inline void debuginfo_query(struct debuginfo_query *q, size_t n)
{
}
static inline void debuginfo_unlock(void)
{
}
#endif
#endif

4
accel/tcg/meson.build
View file

@ -16,10 +16,6 @@ tcg_ss.add(when: 'CONFIG_SYSTEM_ONLY', if_false: files('user-exec-stub.c'))
if get_option('plugins')
tcg_ss.add(files('plugin-gen.c'))
endif
tcg_ss.add(when: libdw, if_true: files('debuginfo.c'))
if host_os == 'linux'
tcg_ss.add(files('perf.c'))
endif
specific_ss.add_all(when: 'CONFIG_TCG', if_true: tcg_ss)
specific_ss.add(when: ['CONFIG_SYSTEM_ONLY', 'CONFIG_TCG'], if_true: files(

383
accel/tcg/perf.c
View file

@ -1,383 +0,0 @@
/*
* Linux perf perf-<pid>.map and jit-<pid>.dump integration.
*
* The jitdump spec can be found at [1].
*
* [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/tools/perf/Documentation/jitdump-specification.txt
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "elf.h"
#include "exec/target_page.h"
#include "exec/exec-all.h"
#include "qemu/timer.h"
#include "tcg/tcg.h"
#include "debuginfo.h"
#include "perf.h"
static FILE *safe_fopen_w(const char *path)
{
int saved_errno;
FILE *f;
int fd;
/* Delete the old file, if any. */
unlink(path);
/* Avoid symlink attacks by using O_CREAT | O_EXCL. */
fd = open(path, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
if (fd == -1) {
return NULL;
}
/* Convert fd to FILE*. */
f = fdopen(fd, "w");
if (f == NULL) {
saved_errno = errno;
close(fd);
errno = saved_errno;
return NULL;
}
return f;
}
static FILE *perfmap;
void perf_enable_perfmap(void)
{
char map_file[32];
snprintf(map_file, sizeof(map_file), "/tmp/perf-%d.map", getpid());
perfmap = safe_fopen_w(map_file);
if (perfmap == NULL) {
warn_report("Could not open %s: %s, proceeding without perfmap",
map_file, strerror(errno));
}
}
/* Get PC and size of code JITed for guest instruction #INSN. */
static void get_host_pc_size(uintptr_t *host_pc, uint16_t *host_size,
const void *start, size_t insn)
{
uint16_t start_off = insn ? tcg_ctx->gen_insn_end_off[insn - 1] : 0;
if (host_pc) {
*host_pc = (uintptr_t)start + start_off;
}
if (host_size) {
*host_size = tcg_ctx->gen_insn_end_off[insn] - start_off;
}
}
static const char *pretty_symbol(const struct debuginfo_query *q, size_t *len)
{
static __thread char buf[64];
int tmp;
if (!q->symbol) {
tmp = snprintf(buf, sizeof(buf), "guest-0x%"PRIx64, q->address);
if (len) {
*len = MIN(tmp + 1, sizeof(buf));
}
return buf;
}
if (!q->offset) {
if (len) {
*len = strlen(q->symbol) + 1;
}
return q->symbol;
}
tmp = snprintf(buf, sizeof(buf), "%s+0x%"PRIx64, q->symbol, q->offset);
if (len) {
*len = MIN(tmp + 1, sizeof(buf));
}
return buf;
}
static void write_perfmap_entry(const void *start, size_t insn,
const struct debuginfo_query *q)
{
uint16_t host_size;
uintptr_t host_pc;
get_host_pc_size(&host_pc, &host_size, start, insn);
fprintf(perfmap, "%"PRIxPTR" %"PRIx16" %s\n",
host_pc, host_size, pretty_symbol(q, NULL));
}
static FILE *jitdump;
static size_t perf_marker_size;
static void *perf_marker = MAP_FAILED;
#define JITHEADER_MAGIC 0x4A695444
#define JITHEADER_VERSION 1
struct jitheader {
uint32_t magic;
uint32_t version;
uint32_t total_size;
uint32_t elf_mach;
uint32_t pad1;
uint32_t pid;
uint64_t timestamp;
uint64_t flags;
};
enum jit_record_type {
JIT_CODE_LOAD = 0,
JIT_CODE_DEBUG_INFO = 2,
};
struct jr_prefix {
uint32_t id;
uint32_t total_size;
uint64_t timestamp;
};
struct jr_code_load {
struct jr_prefix p;
uint32_t pid;
uint32_t tid;
uint64_t vma;
uint64_t code_addr;
uint64_t code_size;
uint64_t code_index;
};
struct debug_entry {
uint64_t addr;
int lineno;
int discrim;
const char name[];
};
struct jr_code_debug_info {
struct jr_prefix p;
uint64_t code_addr;
uint64_t nr_entry;
struct debug_entry entries[];
};
static uint32_t get_e_machine(void)
{
Elf64_Ehdr elf_header;
FILE *exe;
size_t n;
QEMU_BUILD_BUG_ON(offsetof(Elf32_Ehdr, e_machine) !=
offsetof(Elf64_Ehdr, e_machine));
exe = fopen("/proc/self/exe", "r");
if (exe == NULL) {
return EM_NONE;
}
n = fread(&elf_header, sizeof(elf_header), 1, exe);
fclose(exe);
if (n != 1) {
return EM_NONE;
}
return elf_header.e_machine;
}
void perf_enable_jitdump(void)
{
struct jitheader header;
char jitdump_file[32];
if (!use_rt_clock) {
warn_report("CLOCK_MONOTONIC is not available, proceeding without jitdump");
return;
}
snprintf(jitdump_file, sizeof(jitdump_file), "jit-%d.dump", getpid());
jitdump = safe_fopen_w(jitdump_file);
if (jitdump == NULL) {
warn_report("Could not open %s: %s, proceeding without jitdump",
jitdump_file, strerror(errno));
return;
}
/*
* `perf inject` will see that the mapped file name in the corresponding
* PERF_RECORD_MMAP or PERF_RECORD_MMAP2 event is of the form jit-%d.dump
* and will process it as a jitdump file.
*/
perf_marker_size = qemu_real_host_page_size();
perf_marker = mmap(NULL, perf_marker_size, PROT_READ | PROT_EXEC,
MAP_PRIVATE, fileno(jitdump), 0);
if (perf_marker == MAP_FAILED) {
warn_report("Could not map %s: %s, proceeding without jitdump",
jitdump_file, strerror(errno));
fclose(jitdump);
jitdump = NULL;
return;
}
header.magic = JITHEADER_MAGIC;
header.version = JITHEADER_VERSION;
header.total_size = sizeof(header);
header.elf_mach = get_e_machine();
header.pad1 = 0;
header.pid = getpid();
header.timestamp = get_clock();
header.flags = 0;
fwrite(&header, sizeof(header), 1, jitdump);
}
void perf_report_prologue(const void *start, size_t size)
{
if (perfmap) {
fprintf(perfmap, "%"PRIxPTR" %zx tcg-prologue-buffer\n",
(uintptr_t)start, size);
}
}
/* Write a JIT_CODE_DEBUG_INFO jitdump entry. */
static void write_jr_code_debug_info(const void *start,
const struct debuginfo_query *q,
size_t icount)
{
struct jr_code_debug_info rec;
struct debug_entry ent;
uintptr_t host_pc;
int insn;
/* Write the header. */
rec.p.id = JIT_CODE_DEBUG_INFO;
rec.p.total_size = sizeof(rec) + sizeof(ent) + 1;
rec.p.timestamp = get_clock();
rec.code_addr = (uintptr_t)start;
rec.nr_entry = 1;
for (insn = 0; insn < icount; insn++) {
if (q[insn].file) {
rec.p.total_size += sizeof(ent) + strlen(q[insn].file) + 1;
rec.nr_entry++;
}
}
fwrite(&rec, sizeof(rec), 1, jitdump);
/* Write the main debug entries. */
for (insn = 0; insn < icount; insn++) {
if (q[insn].file) {
get_host_pc_size(&host_pc, NULL, start, insn);
ent.addr = host_pc;
ent.lineno = q[insn].line;
ent.discrim = 0;
fwrite(&ent, sizeof(ent), 1, jitdump);
fwrite(q[insn].file, strlen(q[insn].file) + 1, 1, jitdump);
}
}
/* Write the trailing debug_entry. */
ent.addr = (uintptr_t)start + tcg_ctx->gen_insn_end_off[icount - 1];
ent.lineno = 0;
ent.discrim = 0;
fwrite(&ent, sizeof(ent), 1, jitdump);
fwrite("", 1, 1, jitdump);
}
/* Write a JIT_CODE_LOAD jitdump entry. */
static void write_jr_code_load(const void *start, uint16_t host_size,
const struct debuginfo_query *q)
{
static uint64_t code_index;
struct jr_code_load rec;
const char *symbol;
size_t symbol_size;
symbol = pretty_symbol(q, &symbol_size);
rec.p.id = JIT_CODE_LOAD;
rec.p.total_size = sizeof(rec) + symbol_size + host_size;
rec.p.timestamp = get_clock();
rec.pid = getpid();
rec.tid = qemu_get_thread_id();
rec.vma = (uintptr_t)start;
rec.code_addr = (uintptr_t)start;
rec.code_size = host_size;
rec.code_index = code_index++;
fwrite(&rec, sizeof(rec), 1, jitdump);
fwrite(symbol, symbol_size, 1, jitdump);
fwrite(start, host_size, 1, jitdump);
}
void perf_report_code(uint64_t guest_pc, TranslationBlock *tb,
const void *start)
{
struct debuginfo_query *q;
size_t insn, start_words;
uint64_t *gen_insn_data;
if (!perfmap && !jitdump) {
return;
}
q = g_try_malloc0_n(tb->icount, sizeof(*q));
if (!q) {
return;
}
debuginfo_lock();
/* Query debuginfo for each guest instruction. */
gen_insn_data = tcg_ctx->gen_insn_data;
start_words = tcg_ctx->insn_start_words;
for (insn = 0; insn < tb->icount; insn++) {
/* FIXME: This replicates the restore_state_to_opc() logic. */
q[insn].address = gen_insn_data[insn * start_words + 0];
if (tb_cflags(tb) & CF_PCREL) {
q[insn].address |= (guest_pc & qemu_target_page_mask());
}
q[insn].flags = DEBUGINFO_SYMBOL | (jitdump ? DEBUGINFO_LINE : 0);
}
debuginfo_query(q, tb->icount);
/* Emit perfmap entries if needed. */
if (perfmap) {
flockfile(perfmap);
for (insn = 0; insn < tb->icount; insn++) {
write_perfmap_entry(start, insn, &q[insn]);
}
funlockfile(perfmap);
}
/* Emit jitdump entries if needed. */
if (jitdump) {
flockfile(jitdump);
write_jr_code_debug_info(start, q, tb->icount);
write_jr_code_load(start, tcg_ctx->gen_insn_end_off[tb->icount - 1],
q);
funlockfile(jitdump);
}
debuginfo_unlock();
g_free(q);
}
void perf_exit(void)
{
if (perfmap) {
fclose(perfmap);
perfmap = NULL;
}
if (perf_marker != MAP_FAILED) {
munmap(perf_marker, perf_marker_size);
perf_marker = MAP_FAILED;
}
if (jitdump) {
fclose(jitdump);
jitdump = NULL;
}
}

49
accel/tcg/perf.h
View file

@ -1,49 +0,0 @@
/*
* Linux perf perf-<pid>.map and jit-<pid>.dump integration.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef ACCEL_TCG_PERF_H
#define ACCEL_TCG_PERF_H
#if defined(CONFIG_TCG) && defined(CONFIG_LINUX)
/* Start writing perf-<pid>.map. */
void perf_enable_perfmap(void);
/* Start writing jit-<pid>.dump. */
void perf_enable_jitdump(void);
/* Add information about TCG prologue to profiler maps. */
void perf_report_prologue(const void *start, size_t size);
/* Add information about JITted guest code to profiler maps. */
void perf_report_code(uint64_t guest_pc, TranslationBlock *tb,
const void *start);
/* Stop writing perf-<pid>.map and/or jit-<pid>.dump. */
void perf_exit(void);
#else
static inline void perf_enable_perfmap(void)
{
}
static inline void perf_enable_jitdump(void)
{
}
static inline void perf_report_prologue(const void *start, size_t size)
{
}
static inline void perf_report_code(uint64_t guest_pc, TranslationBlock *tb,
const void *start)
{
}
static inline void perf_exit(void)
{
}
#endif
#endif

2
accel/tcg/translate-all.c
View file

@ -63,7 +63,7 @@
#include "tb-context.h"
#include "internal-common.h"
#include "internal-target.h"
#include "perf.h"
#include "tcg/perf.h"
#include "tcg/insn-start-words.h"
TBContext tb_ctx;