[PATCH v3 2/5] perf: util: use capstone disasm engine to show assembly instructions

Changbin Du
2024-01-18T04:12:51Z

Currently, the instructions of samples are shown as raw hex strings
which are hard to read. x86 has a special option '--xed' to disassemble
the hex string via intel XED tool.

Here we use capstone as our disassembler engine to give more friendly
instructions. We select libcapstone because capstone can provide more
insn details. Perf will fallback to raw instructions if libcapstone is
not available.

The advantages compared to XED tool:
* Support arm, arm64, x86-32, x86_64 (more could be supported),
xed only for x86_64.
* Immediate address operands are shown as symbol+offs.

Signed-off-by: Changbin Du <changbin.du@huawei.com>
---
tools/perf/builtin-script.c | 8 +--
tools/perf/util/Build | 1 +
tools/perf/util/print_insn.c | 122 +++++++++++++++++++++++++++++++++++
tools/perf/util/print_insn.h | 14 ++++
4 files changed, 140 insertions(+), 5 deletions(-)
create mode 100644 tools/perf/util/print_insn.c
create mode 100644 tools/perf/util/print_insn.h

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index b1f57401ff23..4817a37f16e2 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -34,6 +34,7 @@
#include "util/event.h"
#include "ui/ui.h"
#include "print_binary.h"
+#include "print_insn.h"
#include "archinsn.h"
#include <linux/bitmap.h>
#include <linux/kernel.h>
@@ -1511,11 +1512,8 @@ static int perf_sample__fprintf_insn(struct perf_sample *sample,
if (PRINT_FIELD(INSNLEN))
printed += fprintf(fp, " ilen: %d", sample->insn_len);
if (PRINT_FIELD(INSN) && sample->insn_len) {
- int i;
-
- printed += fprintf(fp, " insn:");
- for (i = 0; i < sample->insn_len; i++)
- printed += fprintf(fp, " %02x", (unsigned char)sample->insn[i]);
+ printed += fprintf(fp, " insn: ");
+ printed += sample__fprintf_insn_raw(sample, fp);
}
if (PRINT_FIELD(BRSTACKINSN) || PRINT_FIELD(BRSTACKINSNLEN))
printed += perf_sample__fprintf_brstackinsn(sample, thread, attr, machine, fp);
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 988473bf907a..c33aab53d8dd 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -32,6 +32,7 @@ perf-y += perf_regs.o
perf-y += perf-regs-arch/
perf-y += path.o
perf-y += print_binary.o
+perf-y += print_insn.o
perf-y += rlimit.o
perf-y += argv_split.o
perf-y += rbtree.o
diff --git a/tools/perf/util/print_insn.c b/tools/perf/util/print_insn.c
new file mode 100644
index 000000000000..162be4856f79
--- /dev/null
+++ b/tools/perf/util/print_insn.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Instruction binary disassembler based on capstone.
+ *
+ * Author(s): Changbin Du <changbin.du@huawei.com>
+ */
+#include "print_insn.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include "util/debug.h"
+#include "util/symbol.h"
+#include "machine.h"
+
+size_t sample__fprintf_insn_raw(struct perf_sample *sample, FILE *fp)
+{
+ int printed = 0;
+
+ for (int i = 0; i < sample->insn_len; i++)
+ printed += fprintf(fp, "%02x ", (unsigned char)sample->insn[i]);
+ return printed;
+}
+
+#ifdef HAVE_LIBCAPSTONE_SUPPORT
+#include <capstone/capstone.h>
+
+static int capstone_init(struct machine *machine, csh *cs_handle)
+{
+ cs_arch arch;
+ cs_mode mode;
+
+ if (machine__is(machine, "x86_64")) {
+ arch = CS_ARCH_X86;
+ mode = CS_MODE_64;
+ } else if (machine__normalized_is(machine, "x86")) {
+ arch = CS_ARCH_X86;
+ mode = CS_MODE_32;
+ } else if (machine__normalized_is(machine, "arm64")) {
+ arch = CS_ARCH_ARM64;
+ mode = CS_MODE_ARM;
+ } else if (machine__normalized_is(machine, "arm")) {
+ arch = CS_ARCH_ARM;
+ mode = CS_MODE_ARM + CS_MODE_V8;
+ } else if (machine__normalized_is(machine, "s390")) {
+ arch = CS_ARCH_SYSZ;
+ mode = CS_MODE_BIG_ENDIAN;
+ } else {
+ return -1;
+ }
+
+ if (cs_open(arch, mode, cs_handle) != CS_ERR_OK) {
+ pr_warning_once("cs_open failed\n");
+ return -1;
+ }
+
+ cs_option(*cs_handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT);
+ if (machine__normalized_is(machine, "x86"))
+ cs_option(*cs_handle, CS_OPT_DETAIL, CS_OPT_ON);
+
+ return 0;
+}
+
+static size_t print_insn_x86(struct perf_sample *sample, struct thread *thread,
+ cs_insn *insn, FILE *fp)
+{
+ struct addr_location al;
+ size_t printed = 0;
+
+ if (insn->detail && insn->detail->x86.op_count == 1) {
+ cs_x86_op *op = &insn->detail->x86.operands[0];
+
+ addr_location__init(&al);
+
+ if (op->type == X86_OP_IMM &&
+ thread__find_symbol(thread, sample->cpumode, op->imm, &al)) {
+ printed += fprintf(fp, "%s ", insn[0].mnemonic);
+ printed += symbol__fprintf_symname_offs(al.sym, &al, fp);
+ return printed;
+ }
+ }
+
+ printed += fprintf(fp, "%s %s", insn[0].mnemonic, insn[0].op_str);
+ return printed;
+}
+
+size_t sample__fprintf_insn(struct perf_sample *sample, struct thread *thread,
+ struct machine *machine, FILE *fp)
+{
+ static csh cs_handle;
+ cs_insn *insn;
+ size_t count;
+ size_t printed = 0;
+ int ret;
+
+ ret = capstone_init(machine, &cs_handle);
+ if (ret < 0) {
+ /* fallback */
+ return sample__fprintf_insn_raw(sample, fp);
+ }
+
+ count = cs_disasm(cs_handle, (uint8_t *)sample->insn, sample->insn_len,
+ sample->ip, 1, &insn);
+ if (count > 0) {
+ if (machine__normalized_is(machine, "x86"))
+ printed += print_insn_x86(sample, thread, &insn[0], fp);
+ else
+ printed += fprintf(fp, "%s %s", insn[0].mnemonic, insn[0].op_str);
+ cs_free(insn, count);
+ } else {
+ printed += fprintf(fp, "illegal instruction");
+ }
+
+ cs_close(&cs_handle);
+ return printed;
+}
+#else
+size_t sample__fprintf_insn(struct perf_sample *sample, struct thread *thread __maybe_unused,
+ struct machine *machine __maybe_unused, FILE *fp)
+{
+ return sample__fprintf_insn_raw(sample, fp);
+}
+#endif
diff --git a/tools/perf/util/print_insn.h b/tools/perf/util/print_insn.h
new file mode 100644
index 000000000000..af8fa5d01fb7
--- /dev/null
+++ b/tools/perf/util/print_insn.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef PERF_PRINT_ISNS_H
+#define PERF_PRINT_ISNS_H
+
+#include <stddef.h>
+#include <stdio.h>
+#include "event.h"
+#include "util/thread.h"
+
+size_t sample__fprintf_insn(struct perf_sample *sample, struct thread *thread,
+ struct machine *machine, FILE *fp);
+size_t sample__fprintf_insn_raw(struct perf_sample *sample, FILE *fp);
+
+#endif /* PERF_PRINT_ISNS_H */
--
2.25.1