From 8f33f7deac485a61f38aa690b85489322a4d958e Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 6 Feb 2014 05:32:20 +0000 Subject: [PATCH] perf probe: Show appropriate symbol for ref_reloc_sym based kprobes Show appropriate symbol for ref_reloc_sym based kprobes instead of refpoint+offset when perf-probe -l runs without debuginfo. Without this change: # ./perf probe -l probe:t_show (on _stext+889880 with m v) probe:t_show_1 (on _stext+928568 with m v t) probe:t_show_2 (on _stext+969512 with m v fmt) probe:t_show_3 (on _stext+1001416 with m v file) With this change: # ./perf probe -l probe:t_show (on t_show with m v) probe:t_show_1 (on t_show with m v t) probe:t_show_2 (on t_show with m v fmt) probe:t_show_3 (on t_show with m v file) Changes from v2: - Check ref_reloc_sym to find correct unrelocated address. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053220.29635.81819.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-event.c | 83 +++++++++++++++++++++++------------ 1 file changed, 55 insertions(+), 28 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 8e34c8d47813..f86820c39ea4 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -121,6 +121,42 @@ static struct symbol *__find_kernel_function_by_name(const char *name, NULL); } +static struct symbol *__find_kernel_function(u64 addr, struct map **mapp) +{ + return machine__find_kernel_function(host_machine, addr, mapp, NULL); +} + +static struct ref_reloc_sym *kernel_get_ref_reloc_sym(void) +{ + /* kmap->ref_reloc_sym should be set if host_machine is initialized */ + struct kmap *kmap; + + if (map__load(host_machine->vmlinux_maps[MAP__FUNCTION], NULL) < 0) + return NULL; + + kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]); + return kmap->ref_reloc_sym; +} + +static u64 kernel_get_symbol_address_by_name(const char *name, bool reloc) +{ + struct ref_reloc_sym *reloc_sym; + struct symbol *sym; + struct map *map; + + /* ref_reloc_sym is just a label. Need a special fix*/ + reloc_sym = kernel_get_ref_reloc_sym(); + if (reloc_sym && strcmp(name, reloc_sym->name) == 0) + return (reloc) ? reloc_sym->addr : reloc_sym->unrelocated_addr; + else { + sym = __find_kernel_function_by_name(name, &map); + if (sym) + return map->unmap_ip(map, sym->start) - + (reloc) ? 0 : map->reloc; + } + return 0; +} + static struct map *kernel_get_module_map(const char *module) { struct rb_node *nd; @@ -216,12 +252,26 @@ static int convert_exec_to_group(const char *exec, char **result) static int convert_to_perf_probe_point(struct probe_trace_point *tp, struct perf_probe_point *pp) { - pp->function = strdup(tp->symbol); + struct symbol *sym; + struct map *map; + u64 addr = kernel_get_symbol_address_by_name(tp->symbol, true); + + if (addr) { + addr += tp->offset; + sym = __find_kernel_function(addr, &map); + if (!sym) + goto failed; + pp->function = strdup(sym->name); + pp->offset = addr - map->unmap_ip(map, sym->start); + } else { +failed: + pp->function = strdup(tp->symbol); + pp->offset = tp->offset; + } if (pp->function == NULL) return -ENOMEM; - pp->offset = tp->offset; pp->retprobe = tp->retprobe; return 0; @@ -248,18 +298,6 @@ static struct debuginfo *open_debuginfo(const char *module) return debuginfo__new(path); } -static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void) -{ - /* kmap->ref_reloc_sym should be set if host_machine is initialized */ - struct kmap *kmap; - - if (map__load(host_machine->vmlinux_maps[MAP__FUNCTION], NULL) < 0) - return NULL; - - kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]); - return kmap->ref_reloc_sym; -} - /* * Convert trace point to probe point with debuginfo * Currently only handles kprobes. @@ -267,24 +305,13 @@ static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void) static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp, struct perf_probe_point *pp) { - struct symbol *sym; - struct ref_reloc_sym *reloc_sym; - struct map *map; u64 addr = 0; int ret = -ENOENT; struct debuginfo *dinfo; - /* ref_reloc_sym is just a label. Need a special fix*/ - reloc_sym = __kernel_get_ref_reloc_sym(); - if (reloc_sym && strcmp(tp->symbol, reloc_sym->name) == 0) - addr = reloc_sym->unrelocated_addr + tp->offset; - else { - sym = __find_kernel_function_by_name(tp->symbol, &map); - if (sym) - addr = map->unmap_ip(map, sym->start + tp->offset) - - map->reloc; - } + addr = kernel_get_symbol_address_by_name(tp->symbol, false); if (addr) { + addr += tp->offset; pr_debug("try to find %s+%ld@%" PRIx64 "\n", tp->symbol, tp->offset, addr); @@ -420,7 +447,7 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs, if (module) return add_module_to_probe_trace_events(tevs, ntevs, module); - reloc_sym = __kernel_get_ref_reloc_sym(); + reloc_sym = kernel_get_ref_reloc_sym(); if (!reloc_sym) { pr_warning("Relocated base symbol is not found!\n"); return -EINVAL;