perf, tools, script: Add support for printing assembler When dumping PT traces with perf script it is very useful to see the assembler for each sample, so that it is easily possible to follow the control flow. As using objdump is difficult and inefficient from perf script this patch uses the udis86 library to implement assembler output. The library can be downloaded from http://udis86.sourceforge.net/ The library is probed as an external dependency in the usual way. Then perf script calls into it when needed, and handles callbacks to resolve symbols. % perf record -e intel_pt//u true % perf script -F sym,symoff,ip,asm --itrace=i0ns | head 7fc7188b4190 _start+0x0 mov %rsp, %rdi 7fc7188b4193 _start+0x3 call _dl_start 7fc7188b7710 _dl_start+0x0 push %rbp 7fc7188b7711 _dl_start+0x1 mov %rsp, %rbp 7fc7188b7714 _dl_start+0x4 push %r15 7fc7188b7716 _dl_start+0x6 push %r14 7fc7188b7718 _dl_start+0x8 push %r13 7fc7188b771a _dl_start+0xa push %r12 7fc7188b771c _dl_start+0xc mov %rdi, %r12 7fc7188b771f _dl_start+0xf push %rbx Current issues: - Some jump references do not get resolved to symbols. - udis86 release does not support STAC/CLAC, which are used in the kernel, but there is a pending patch for it. Cc: adrian.hunter@intel.com v2: Fix address resolution. Port to latest acme/perf/core Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt index 4fc44c7..5453637 100644 --- a/tools/perf/Documentation/perf-script.txt +++ b/tools/perf/Documentation/perf-script.txt
@@ -116,7 +116,7 @@ --fields:: Comma separated list of fields to print. Options are: comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff, - srcline, period, iregs, brstack, brstacksym, flags. + srcline, period, iregs, brstack, brstacksym, flags, asm. Field list can be prepended with the type, trace, sw or hw, to indicate to which event type the field list applies. e.g., -f sw:comm,tid,time,ip,sym and -f trace:time,cpu,trace @@ -185,6 +185,8 @@ The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible. + When asm is specified the assembler instruction of each sample is printed in disassembled form. + -k:: --vmlinux=<file>:: vmlinux pathname
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index e3ce2f3..c8a91a8 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c
@@ -26,6 +26,10 @@ #include "asm/bug.h" #include "util/mem-events.h" +#ifdef HAVE_UDIS86 +#include <udis86.h> +#endif + static char const *script_name; static char const *generate_script_lang; static bool debug_mode; @@ -63,6 +67,7 @@ PERF_OUTPUT_DATA_SRC = 1U << 17, PERF_OUTPUT_WEIGHT = 1U << 18, PERF_OUTPUT_BPF_OUTPUT = 1U << 19, + PERF_OUTPUT_ASM = 1U << 20, }; struct output_option { @@ -89,6 +94,7 @@ {.str = "data_src", .field = PERF_OUTPUT_DATA_SRC}, {.str = "weight", .field = PERF_OUTPUT_WEIGHT}, {.str = "bpf-output", .field = PERF_OUTPUT_BPF_OUTPUT}, + {.str = "asm", .field = PERF_OUTPUT_ASM}, }; /* default set to maintain compatibility with current format */ @@ -283,7 +289,11 @@ "selected. Hence, no address to lookup the source line number.\n"); return -EINVAL; } - + if (PRINT_FIELD(ASM) && !PRINT_FIELD(IP)) { + pr_err("Display of assembler requested but sample IP is not\n" + "selected.\n"); + return -EINVAL; + } if ((PRINT_FIELD(PID) || PRINT_FIELD(TID)) && perf_evsel__check_stype(evsel, PERF_SAMPLE_TID, "TID", PERF_OUTPUT_TID|PERF_OUTPUT_PID)) @@ -422,6 +432,88 @@ } } +#ifdef HAVE_UDIS86 + +struct perf_ud { + ud_t ud_obj; + struct thread *thread; + u8 cpumode; + int cpu; +}; + +static const char *dis_resolve(struct ud *u, uint64_t addr, int64_t *off) +{ + struct perf_ud *ud = container_of(u, struct perf_ud, ud_obj); + struct addr_location al; + + memset(&al, 0, sizeof(struct addr_location)); + + thread__find_addr_map(ud->thread, ud->cpumode, MAP__FUNCTION, addr, &al); + if (!al.map) + thread__find_addr_map(ud->thread, ud->cpumode, MAP__VARIABLE, + addr, &al); + al.cpu = ud->cpu; + al.sym = NULL; + + if (al.map) + al.sym = map__find_symbol(al.map, al.addr, NULL); + + if (!al.sym) + return NULL; + + if (al.addr < al.sym->end) + *off = al.addr - al.sym->start; + else + *off = al.addr - al.map->start - al.sym->start; + return al.sym->name; +} +#endif + +static void print_sample_asm(struct perf_sample *sample __maybe_unused, + struct thread *thread __maybe_unused, + struct perf_event_attr *attr __maybe_unused, + struct addr_location *al __maybe_unused, + struct machine *machine __maybe_unused) +{ +#ifdef HAVE_UDIS86 + static bool ud_initialized = false; + static struct perf_ud ud; + u8 buffer[32]; + int len; + u64 offset; + + if (!ud_initialized) { + ud_initialized = true; + ud_init(&ud.ud_obj); + ud_set_syntax(&ud.ud_obj, UD_SYN_ATT); + ud_set_sym_resolver(&ud.ud_obj, dis_resolve); + } + ud.thread = thread; + ud.cpumode = sample->cpumode; + ud.cpu = sample->cpu; + + if (!al->map || !al->map->dso) + return; + if (al->map->dso->data.status == DSO_DATA_STATUS_ERROR) + return; + + /* Load maps to ensure dso->is_64_bit has been updated */ + map__load(al->map, machine->symbol_filter); + + offset = al->map->map_ip(al->map, sample->ip); + len = dso__data_read_offset(al->map->dso, machine, + offset, buffer, 32); + if (len <= 0) + return; + + ud_set_mode(&ud.ud_obj, al->map->dso->is_64_bit ? 64 : 32); + ud_set_pc(&ud.ud_obj, sample->ip); + ud_set_input_buffer(&ud.ud_obj, buffer, len); + ud_disassemble(&ud.ud_obj); + printf("\t%s", ud_insn_asm(&ud.ud_obj)); +#endif +} + static void print_sample_start(struct perf_sample *sample, struct thread *thread, struct perf_evsel *evsel) @@ -562,7 +654,8 @@ static void print_sample_bts(struct perf_sample *sample, struct perf_evsel *evsel, struct thread *thread, - struct addr_location *al) + struct addr_location *al, + struct machine *machine) { struct perf_event_attr *attr = &evsel->attr; bool print_srcline_last = false; @@ -597,6 +690,9 @@ print_sample_addr(sample, thread, attr); } + if (PRINT_FIELD(ASM)) + print_sample_asm(sample, thread, attr, al, machine); + if (print_srcline_last) map__fprintf_srcline(al->map, al->addr, "\n ", stdout); @@ -745,7 +841,8 @@ static void process_event(struct perf_script *script, struct perf_sample *sample, struct perf_evsel *evsel, - struct addr_location *al) + struct addr_location *al, + struct machine *machine) { struct thread *thread = al->thread; struct perf_event_attr *attr = &evsel->attr; @@ -772,7 +869,7 @@ print_sample_flags(sample->flags); if (is_bts_event(attr)) { - print_sample_bts(sample, evsel, thread, al); + print_sample_bts(sample, evsel, thread, al, machine); return; } @@ -811,6 +908,9 @@ if (perf_evsel__is_bpf_output(evsel) && PRINT_FIELD(BPF_OUTPUT)) print_sample_bpf_output(sample); + if (PRINT_FIELD(ASM)) + print_sample_asm(sample, thread, attr, al, machine); + printf("\n"); } @@ -917,7 +1017,7 @@ if (scripting_ops) scripting_ops->process_event(event, sample, evsel, &al); else - process_event(scr, sample, evsel, &al); + process_event(scr, sample, evsel, &al, machine); out_put: addr_location__put(&al); @@ -2017,7 +2117,7 @@ "comma separated output fields prepend with 'type:'. " "Valid types: hw,sw,trace,raw. " "Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso," - "addr,symoff,period,iregs,brstack,brstacksym,flags", parse_output_fields), + "addr,symoff,period,iregs,brstack,brstacksym,flags,asm", parse_output_fields), OPT_BOOLEAN('a', "all-cpus", &system_wide, "system-wide collection from all CPUs"), OPT_STRING('S', "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",