[PATCH v9 04/18] perf capstone: Determine architecture from e_machine

Ian Rogers
2026-05-03T00:23:01Z

Avoid the use of arch string that is imprecise and use the
e_machine. Do more e_machine to capstone machine translations adding
MIPS and RISCV. Remove unnecessary maybe_unused annotations.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/capstone.c | 129 ++++++++++++++++++++++++-------------
1 file changed, 85 insertions(+), 44 deletions(-)

diff --git a/tools/perf/util/capstone.c b/tools/perf/util/capstone.c
index 25cf6e15ec27..870394b46911 100644
--- a/tools/perf/util/capstone.c
+++ b/tools/perf/util/capstone.c
@@ -1,7 +1,19 @@
// SPDX-License-Identifier: GPL-2.0
#include "capstone.h"
-#include "annotate.h"
+
+#include <errno.h>
+#include <inttypes.h>
+#include <string.h>
+
+#include <dlfcn.h>
+#include <elf.h>
+#include <fcntl.h>
+#include <linux/ctype.h>
+
+#include <capstone/capstone.h>
+
#include "addr_location.h"
+#include "annotate.h"
#include "debug.h"
#include "disasm.h"
#include "dso.h"
@@ -11,13 +23,6 @@
#include "print_insn.h"
#include "symbol.h"
#include "thread.h"
-#include <dlfcn.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <inttypes.h>
-#include <string.h>
-
-#include <capstone/capstone.h>

#ifdef LIBCAPSTONE_DLOPEN
static void *perf_cs_dll_handle(void)
@@ -137,37 +142,67 @@ static enum cs_err perf_cs_close(csh *handle)
#endif
}

-static int capstone_init(struct machine *machine, csh *cs_handle, bool is64,
+static bool e_machine_to_capstone(uint16_t e_machine, bool is64, bool is_big_endian,
+ enum cs_arch *arch, enum cs_mode *mode)
+{
+ *mode = is_big_endian ? CS_MODE_BIG_ENDIAN : CS_MODE_LITTLE_ENDIAN;
+ *mode |= is64 ? CS_MODE_64 : CS_MODE_32;
+
+ switch (e_machine) {
+ case EM_X86_64:
+ case EM_386:
+ *arch = CS_ARCH_X86;
+ return true;
+ case EM_AARCH64:
+ *arch = CS_ARCH_ARM64;
+ *mode |= CS_MODE_ARM;
+ return true;
+ case EM_ARM:
+ *arch = CS_ARCH_ARM;
+ *mode |= CS_MODE_ARM | CS_MODE_V8;
+ return true;
+ case EM_S390:
+ *arch = CS_ARCH_SYSZ;
+ return true;
+ case EM_MIPS:
+ *arch = CS_ARCH_MIPS;
+ *mode |= is64 ? CS_MODE_MIPS64 : CS_MODE_MIPS32;
+ return true;
+ case EM_PPC:
+ case EM_PPC64:
+ *arch = CS_ARCH_PPC;
+ return true;
+ case EM_SPARC:
+ *arch = CS_ARCH_SPARC;
+ return true;
+ case EM_SPARCV9:
+ *arch = CS_ARCH_SPARC;
+ *mode |= CS_MODE_V9;
+ return true;
+ case EM_RISCV:
+ *arch = CS_ARCH_RISCV;
+ *mode |= is64 ? CS_MODE_RISCV64 : CS_MODE_RISCV32;
+ return true;
+ default:
+ return false;
+ }
+}
+
+static int capstone_init(uint16_t e_machine, csh *cs_handle, bool is64, bool is_big_endian,
bool disassembler_style)
{
enum cs_arch arch;
enum cs_mode mode;

- if (machine__is(machine, "x86_64") && is64) {
- 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 {
+ if (!e_machine_to_capstone(e_machine, is64, is_big_endian, &arch, &mode))
return -1;
- }

if (perf_cs_open(arch, mode, cs_handle) != CS_ERR_OK) {
pr_warning_once("cs_open failed\n");
return -1;
}

- if (machine__normalized_is(machine, "x86")) {
+ if (arch == CS_ARCH_X86) {
/*
* In case of using capstone_init while symbol__disassemble
* setting CS_OPT_SYNTAX_ATT depends if disassembler_style opts
@@ -211,29 +246,28 @@ static size_t print_insn_x86(struct thread *thread, u8 cpumode, struct cs_insn *
return printed;
}

-
-ssize_t capstone__fprintf_insn_asm(struct machine *machine __maybe_unused,
- struct thread *thread __maybe_unused,
- u8 cpumode __maybe_unused, bool is64bit __maybe_unused,
- const uint8_t *code __maybe_unused,
- size_t code_size __maybe_unused,
- uint64_t ip __maybe_unused, int *lenp __maybe_unused,
- int print_opts __maybe_unused, FILE *fp __maybe_unused)
+ssize_t capstone__fprintf_insn_asm(struct machine *machine, struct thread *thread, u8 cpumode,
+ bool is64bit, const uint8_t *code, size_t code_size, uint64_t ip,
+ int *lenp, int print_opts, FILE *fp)
{
size_t printed;
struct cs_insn *insn;
csh cs_handle;
size_t count;
+ bool is_big_endian = false;
+ uint16_t e_machine = thread__e_machine_endian(thread, machine,
+ /*e_flags=*/NULL, &is_big_endian);
int ret;

/* TODO: Try to initiate capstone only once but need a proper place. */
- ret = capstone_init(machine, &cs_handle, is64bit, true);
+ ret = capstone_init(e_machine, &cs_handle, is64bit, is_big_endian,
+ /*disassembler_style=*/true);
if (ret < 0)
return ret;

count = perf_cs_disasm(cs_handle, code, code_size, ip, 1, &insn);
if (count > 0) {
- if (machine__normalized_is(machine, "x86"))
+ if (e_machine == EM_X86_64 || e_machine == EM_386)
printed = print_insn_x86(thread, cpumode, &insn[0], print_opts, fp);
else
printed = fprintf(fp, "%s %s", insn[0].mnemonic, insn[0].op_str);
@@ -322,9 +356,8 @@ static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg)
return 0;
}

-int symbol__disassemble_capstone(const char *filename __maybe_unused,
- struct symbol *sym __maybe_unused,
- struct annotate_args *args __maybe_unused)
+int symbol__disassemble_capstone(const char *filename, struct symbol *sym,
+ struct annotate_args *args)
{
struct annotation *notes = symbol__annotation(sym);
struct map *map = args->ms->map;
@@ -344,6 +377,8 @@ int symbol__disassemble_capstone(const char *filename __maybe_unused,
char disasm_buf[512];
struct disasm_line *dl;
bool disassembler_style = false;
+ uint16_t e_machine;
+ bool is_big_endian = false;

if (args->options->objdump_path)
return -1;
@@ -373,8 +408,10 @@ int symbol__disassemble_capstone(const char *filename __maybe_unused,
!strcmp(args->options->disassembler_style, "att"))
disassembler_style = true;

- if (capstone_init(maps__machine(thread__maps(args->ms->thread)), &handle, is_64bit,
- disassembler_style) < 0)
+ e_machine = thread__e_machine_endian(args->ms->thread,
+ /*machine=*/NULL,
+ /*e_flags=*/NULL, &is_big_endian);
+ if (capstone_init(e_machine, &handle, is_64bit, is_big_endian, disassembler_style) < 0)
goto err;

needs_cs_close = true;
@@ -466,6 +503,8 @@ int symbol__disassemble_capstone_powerpc(const char *filename __maybe_unused,
struct disasm_line *dl;
u32 *line;
bool disassembler_style = false;
+ uint16_t e_machine;
+ bool is_big_endian = false;

if (args->options->objdump_path)
return -1;
@@ -484,8 +523,10 @@ int symbol__disassemble_capstone_powerpc(const char *filename __maybe_unused,
!strcmp(args->options->disassembler_style, "att"))
disassembler_style = true;

- if (capstone_init(maps__machine(thread__maps(args->ms->thread)), &handle, is_64bit,
- disassembler_style) < 0)
+ e_machine = thread__e_machine_endian(args->ms->thread,
+ /*machine=*/NULL,
+ /*e_flags=*/NULL, &is_big_endian);
+ if (capstone_init(e_machine, &handle, is_64bit, is_big_endian, disassembler_style) < 0)
goto err;

needs_cs_close = true;
--
2.54.0.545.g6539524ca2-goog