Messages in this thread Patch in this message |  | | Date | Mon, 22 Jan 2024 16:42:16 +0800 | | From | Changbin Du <> | | Subject | Re: [PATCH v4 2/5] perf: util: use capstone disasm engine to show assembly instructions |
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On Mon, Jan 22, 2024 at 10:24:21AM +0200, Adrian Hunter wrote: > On 20/01/24 11:13, Changbin Du wrote: > > On Fri, Jan 19, 2024 at 08:39:19PM +0200, Adrian Hunter wrote: > >> On 19/01/24 12:48, 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> > >>> --- > >>> 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: "); > >> > >> "insn:" seems unnecessary. Also xed prints 2 tabs, which > >> helps line up the output. Perhaps 1 tab and 2 spaces is > >> enough. > >> > > The "insn:" is used by xed. So it can not be removed if we preserve xed > > function. > > I got mixed up - it is patch 3 that the comment is meant for. > > > > > For 'insn' field, I keep the original output format. > > For 'disasm' field, we can line up the output. I changed to 2 tabs and removed > > 'insn:'. > > That is better, thanks! > > > > >>> + 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" > >> > >> Please put with the other non-system includes > >> > > done. > > > >>> +#include <stdlib.h> > >>> +#include <string.h> > >>> +#include <stdbool.h> > >>> +#include "util/debug.h" > >> > >> util/ not needed > >> > > done. > > > >>> +#include "util/symbol.h" > >> > >> util/ not needed > >> > > done. > > > >>> +#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]); > >> > >> Why change this to put a space on the end? > >> > > Removed the tailing space. > > > >>> + 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); > >> > >> That's only needed for x86 isn't it > >> > > Moved into below branch. > > > >>> + if (machine__normalized_is(machine, "x86")) > >>> + cs_option(*cs_handle, CS_OPT_DETAIL, CS_OPT_ON); > >> > >> Why? Could use a comment. > >> > > /* > > * Resolving address oprands to symbols is implemented > > oprands -> operands Fixed, thanks!
> > > * on x86 by investigating instruction details. > > */ > > > >>> + > >>> + 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); > >> > >> Missing addr_location__exit() > >> > > Fixed. > > > >>> + > >>> + 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; > >> > >> Why static? > >> > > Removed. See below. > > > >>> + cs_insn *insn; > >>> + size_t count; > >>> + size_t printed = 0; > >>> + int ret; > >>> + > >>> + ret = capstone_init(machine, &cs_handle); > >> > >> Does this really need to be done every time? > >> > > Only need to init once exactly. The problem is I cannot find a appropriate > > place to do the initiation. > > > > I tried to initiate on first call but we still need a global mutex to be > > initiated. > > > > So finally I fallback to initiate every time. The redundant initiation is > > acceptable per my test. > > OK, could add a FIXME > I added a TODO instead.
/* TODO: Try to initiate capstone only once but need a proper place. */
> > > >>> + 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 > >> Here and elsewhere > >> > >> ISNS -> INSN > >> > > fixed. > > > >>> +#define PERF_PRINT_ISNS_H > >>> + > >>> +#include <stddef.h> > >>> +#include <stdio.h> > >>> +#include "event.h" > >>> +#include "util/thread.h" > >> > >> Instead of including event.h and thread.h, just forward declare: > >> > >> struct perf_sample; > >> struct thread; > >> struct machine; > >> > > Why forward declaration? > > That is how it is done in perf tools. It avoids unnecessary dependency > among headers. ok, done.
> > > > >>> + > >>> +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 */ > >> > > >
-- Cheers, Changbin Du
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