diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 265425322734eecfc3087a7be42a60960c89f2b0..8f88420e066bb9b14fdd1aa0fda69fe6c600a356 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -551,6 +551,13 @@ static int __cmd_record(int argc, const char **argv) return err; } + err = event__synthesize_kernel_mmap(process_synthesized_event, + session, "_text"); + if (err < 0) { + pr_err("Couldn't record kernel reference relocation symbol.\n"); + return err; + } + if (!system_wide && profile_cpu == -1) event__synthesize_thread(pid, process_synthesized_event, session); diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index bb0fd6da2d56f3850885d1d51df089dccc15d1d6..1a31feb9999f8fa4043db9b019cc989e9f34bddd 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -189,6 +189,50 @@ void event__synthesize_threads(int (*process)(event_t *event, closedir(proc); } +struct process_symbol_args { + const char *name; + u64 start; +}; + +static int find_symbol_cb(void *arg, const char *name, char type, u64 start) +{ + struct process_symbol_args *args = arg; + + if (!symbol_type__is_a(type, MAP__FUNCTION) || strcmp(name, args->name)) + return 0; + + args->start = start; + return 1; +} + +int event__synthesize_kernel_mmap(int (*process)(event_t *event, + struct perf_session *session), + struct perf_session *session, + const char *symbol_name) +{ + size_t size; + event_t ev = { + .header = { .type = PERF_RECORD_MMAP }, + }; + /* + * We should get this from /sys/kernel/sections/.text, but till that is + * available use this, and after it is use this as a fallback for older + * kernels. + */ + struct process_symbol_args args = { .name = symbol_name, }; + + if (kallsyms__parse(&args, find_symbol_cb) <= 0) + return -ENOENT; + + size = snprintf(ev.mmap.filename, sizeof(ev.mmap.filename), + "[kernel.kallsyms.%s]", symbol_name) + 1; + size = ALIGN(size, sizeof(u64)); + ev.mmap.header.size = (sizeof(ev.mmap) - (sizeof(ev.mmap.filename) - size)); + ev.mmap.start = args.start; + + return process(&ev, session); +} + static void thread__comm_adjust(struct thread *self) { char *comm = self->comm; @@ -240,9 +284,9 @@ int event__process_lost(event_t *self, struct perf_session *session) int event__process_mmap(event_t *self, struct perf_session *session) { - struct thread *thread = perf_session__findnew(session, self->mmap.pid); - struct map *map = map__new(&self->mmap, MAP__FUNCTION, - session->cwd, session->cwdlen); + struct thread *thread; + struct map *map; + static const char kmmap_prefix[] = "[kernel.kallsyms."; dump_printf(" %d/%d: [%p(%p) @ %p]: %s\n", self->mmap.pid, self->mmap.tid, @@ -251,6 +295,20 @@ int event__process_mmap(event_t *self, struct perf_session *session) (void *)(long)self->mmap.pgoff, self->mmap.filename); + if (self->mmap.pid == 0 && + memcmp(self->mmap.filename, kmmap_prefix, + sizeof(kmmap_prefix) - 1) == 0) { + const char *symbol_name = (self->mmap.filename + + sizeof(kmmap_prefix) - 1); + perf_session__set_kallsyms_ref_reloc_sym(session, symbol_name, + self->mmap.start); + return 0; + } + + thread = perf_session__findnew(session, self->mmap.pid); + map = map__new(&self->mmap, MAP__FUNCTION, + session->cwd, session->cwdlen); + if (thread == NULL || map == NULL) dump_printf("problem processing PERF_RECORD_MMAP, skipping event.\n"); else diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h index 80fb3653c809c9a23ab138ef3a3277783127b1d9..61fc0dc658c2f31d8663d36fe6bb269b71a5d8e1 100644 --- a/tools/perf/util/event.h +++ b/tools/perf/util/event.h @@ -110,6 +110,10 @@ int event__synthesize_thread(pid_t pid, void event__synthesize_threads(int (*process)(event_t *event, struct perf_session *session), struct perf_session *session); +int event__synthesize_kernel_mmap(int (*process)(event_t *event, + struct perf_session *session), + struct perf_session *session, + const char *symbol_name); int event__process_comm(event_t *self, struct perf_session *session); int event__process_lost(event_t *self, struct perf_session *session); diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 7f0537d1add8de0039f193798826f8fe1c6f6d31..e0e6a075489e79ea2d5b6eb767b64eb5163c6c09 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -401,3 +401,49 @@ bool perf_session__has_traces(struct perf_session *self, const char *msg) return true; } + +int perf_session__set_kallsyms_ref_reloc_sym(struct perf_session *self, + const char *symbol_name, + u64 addr) +{ + char *bracket; + + self->ref_reloc_sym.name = strdup(symbol_name); + if (self->ref_reloc_sym.name == NULL) + return -ENOMEM; + + bracket = strchr(self->ref_reloc_sym.name, ']'); + if (bracket) + *bracket = '\0'; + + self->ref_reloc_sym.addr = addr; + return 0; +} + +static u64 map__reloc_map_ip(struct map *map, u64 ip) +{ + return ip + (s64)map->pgoff; +} + +static u64 map__reloc_unmap_ip(struct map *map, u64 ip) +{ + return ip - (s64)map->pgoff; +} + +void perf_session__reloc_vmlinux_maps(struct perf_session *self, + u64 unrelocated_addr) +{ + enum map_type type; + s64 reloc = unrelocated_addr - self->ref_reloc_sym.addr; + + if (!reloc) + return; + + for (type = 0; type < MAP__NR_TYPES; ++type) { + struct map *map = self->vmlinux_maps[type]; + + map->map_ip = map__reloc_map_ip; + map->unmap_ip = map__reloc_unmap_ip; + map->pgoff = reloc; + } +} diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h index 8db37bbf0e626387598102b498041679870e4fce..d4a9d20f8d444cc534ed8a77a4bccd9d1e0a5ddd 100644 --- a/tools/perf/util/session.h +++ b/tools/perf/util/session.h @@ -24,6 +24,10 @@ struct perf_session { unsigned long unknown_events; struct rb_root hists; u64 sample_type; + struct { + const char *name; + u64 addr; + } ref_reloc_sym; int fd; int cwdlen; char *cwd; @@ -59,4 +63,10 @@ bool perf_session__has_traces(struct perf_session *self, const char *msg); int perf_header__read_build_ids(int input, u64 offset, u64 file_size); +int perf_session__set_kallsyms_ref_reloc_sym(struct perf_session *self, + const char *symbol_name, + u64 addr); +void perf_session__reloc_vmlinux_maps(struct perf_session *self, + u64 unrelocated_addr); + #endif /* __PERF_SESSION_H */ diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index e290429e9c0075f7b6843771c2624755099d1dc4..da2f07f1af8fc0d3ac45031ca5139d2f02c5dd63 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -956,11 +956,15 @@ static int dso__load_sym(struct dso *self, struct map *map, elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { struct symbol *f; - const char *elf_name; + const char *elf_name = elf_sym__name(&sym, symstrs); char *demangled = NULL; int is_label = elf_sym__is_label(&sym); const char *section_name; + if (kernel && session->ref_reloc_sym.name != NULL && + strcmp(elf_name, session->ref_reloc_sym.name) == 0) + perf_session__reloc_vmlinux_maps(session, sym.st_value); + if (!is_label && !elf_sym__is_a(&sym, map->type)) continue; @@ -973,7 +977,6 @@ static int dso__load_sym(struct dso *self, struct map *map, if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type)) continue; - elf_name = elf_sym__name(&sym, symstrs); section_name = elf_sec__name(&shdr, secstrs); if (kernel || kmodule) {