Messages in this thread | | | Date | Tue, 6 Feb 2024 12:33:10 +0200 | Subject | Re: [PATCH v6 2/5] perf: util: use capstone disasm engine to show assembly instructions | From | Adrian Hunter <> |
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On 6/02/24 04:14, Changbin Du wrote: > 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> > > --- > v3: > - show warning msg if libcapstone is not available. > v2: > - line up the output by preceding two tabs. (Adrian Hunter) > - removed the tailing space. (Adrian Hunter) > - forward declaration for perf_sample, thread, machine. (Adrian Hunter) > - other trivial fixes (Adrian Hunter) > --- > tools/perf/builtin-script.c | 8 +-- > tools/perf/util/Build | 1 + > tools/perf/util/print_insn.c | 134 +++++++++++++++++++++++++++++++++++ > tools/perf/util/print_insn.h | 16 +++++ > 4 files changed, 154 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 8027f450fa3e..2cbeeb79b6ef 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..163307a02274 > --- /dev/null > +++ b/tools/perf/util/print_insn.c > @@ -0,0 +1,134 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Instruction binary disassembler based on capstone. > + * > + * Author(s): Changbin Du <changbin.du@huawei.com> > + */ > +#include <string.h> > +#include <stdbool.h> > +#include "debug.h" > +#include "event.h" > +#include "symbol.h" > +#include "machine.h" > +#include "thread.h" > +#include "print_insn.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]);
Same as last time, there are 2 spaces between bytes instead of 1. It needs:
"%02x " -> "%02x"
> + if (sample->insn_len - i > 1) > + printed += fprintf(fp, " "); > + } > + 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; > + } > + > + if (machine__normalized_is(machine, "x86")) { > + cs_option(*cs_handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT); > + /* > + * Resolving address operands to symbols is implemented > + * on x86 by investigating instruction details. > + */ > + 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); > + addr_location__exit(&al); > + return printed; > + } > + addr_location__exit(&al); > + } > + > + 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) > +{ > + csh cs_handle; > + cs_insn *insn; > + size_t count; > + size_t printed = 0; > + int ret; > + > + /* TODO: Try to initiate capstone only once but need a proper place. */ > + 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) > +{ > + pr_warning_once("perf needs to be built with libcapstone support to disassemble instructions\n"); > + return sample__fprintf_insn_raw(sample, fp);
The validation stops this being called so could just leave out the 2 lines above, and add __maybe_unused as necessary.
> +} > +#endif > diff --git a/tools/perf/util/print_insn.h b/tools/perf/util/print_insn.h > new file mode 100644 > index 000000000000..80dda6da7c60 > --- /dev/null > +++ b/tools/perf/util/print_insn.h > @@ -0,0 +1,16 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef PERF_PRINT_INSN_H > +#define PERF_PRINT_INSN_H > + > +#include <stddef.h> > +#include <stdio.h> > + > +struct perf_sample; > +struct thread; > +struct machine; > + > +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_INSN_H */
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