From 33a2471cc9b7b1fb27ff2031dbaff701644b1a4d Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 22 Jul 2015 12:36:55 -0300 Subject: [PATCH] tools lib traceevent: Allow setting an alternative symbol resolver The perf tools have a symbol resolver that includes solving kernel symbols using either kallsyms or ELF symtabs, and it also is using libtraceevent to format the trace events fields, including via subsystem specific plugins, like the "timer" one. To solve fields like "timer:hrtimer_start"'s "function", libtraceevent needs a way to map from its value to a function name and addr. This patch provides a way for tools that already have symbol resolving facilities to ask libtraceevent to use it when needing to resolve kernel symbols. Reviewed-by: Steven Rostedt Acked-by: David Ahern Cc: Adrian Hunter Cc: Borislav Petkov Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-fdx1fazols17w5py26ia3bwh@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/traceevent/event-parse.c | 68 +++++++++++++++++++++++++++++- tools/lib/traceevent/event-parse.h | 8 ++++ 2 files changed, 75 insertions(+), 1 deletion(-) diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c index cc25f059ab3d..fcd8a9e3d2e1 100644 --- a/tools/lib/traceevent/event-parse.c +++ b/tools/lib/traceevent/event-parse.c @@ -418,7 +418,7 @@ static int func_map_init(struct pevent *pevent) } static struct func_map * -find_func(struct pevent *pevent, unsigned long long addr) +__find_func(struct pevent *pevent, unsigned long long addr) { struct func_map *func; struct func_map key; @@ -434,6 +434,71 @@ find_func(struct pevent *pevent, unsigned long long addr) return func; } +struct func_resolver { + pevent_func_resolver_t *func; + void *priv; + struct func_map map; +}; + +/** + * pevent_set_function_resolver - set an alternative function resolver + * @pevent: handle for the pevent + * @resolver: function to be used + * @priv: resolver function private state. + * + * Some tools may have already a way to resolve kernel functions, allow them to + * keep using it instead of duplicating all the entries inside + * pevent->funclist. + */ +int pevent_set_function_resolver(struct pevent *pevent, + pevent_func_resolver_t *func, void *priv) +{ + struct func_resolver *resolver = malloc(sizeof(*resolver)); + + if (resolver == NULL) + return -1; + + resolver->func = func; + resolver->priv = priv; + + free(pevent->func_resolver); + pevent->func_resolver = resolver; + + return 0; +} + +/** + * pevent_reset_function_resolver - reset alternative function resolver + * @pevent: handle for the pevent + * + * Stop using whatever alternative resolver was set, use the default + * one instead. + */ +void pevent_reset_function_resolver(struct pevent *pevent) +{ + free(pevent->func_resolver); + pevent->func_resolver = NULL; +} + +static struct func_map * +find_func(struct pevent *pevent, unsigned long long addr) +{ + struct func_map *map; + + if (!pevent->func_resolver) + return __find_func(pevent, addr); + + map = &pevent->func_resolver->map; + map->mod = NULL; + map->addr = addr; + map->func = pevent->func_resolver->func(pevent->func_resolver->priv, + &map->addr, &map->mod); + if (map->func == NULL) + return NULL; + + return map; +} + /** * pevent_find_function - find a function by a given address * @pevent: handle for the pevent @@ -6564,6 +6629,7 @@ void pevent_free(struct pevent *pevent) free(pevent->trace_clock); free(pevent->events); free(pevent->sort_events); + free(pevent->func_resolver); free(pevent); } diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h index 063b1971eb35..204befb05a17 100644 --- a/tools/lib/traceevent/event-parse.h +++ b/tools/lib/traceevent/event-parse.h @@ -453,6 +453,10 @@ struct cmdline_list; struct func_map; struct func_list; struct event_handler; +struct func_resolver; + +typedef char *(pevent_func_resolver_t)(void *priv, + unsigned long long *addrp, char **modp); struct pevent { int ref_count; @@ -481,6 +485,7 @@ struct pevent { int cmdline_count; struct func_map *func_map; + struct func_resolver *func_resolver; struct func_list *funclist; unsigned int func_count; @@ -611,6 +616,9 @@ enum trace_flag_type { TRACE_FLAG_SOFTIRQ = 0x10, }; +int pevent_set_function_resolver(struct pevent *pevent, + pevent_func_resolver_t *func, void *priv); +void pevent_reset_function_resolver(struct pevent *pevent); int pevent_register_comm(struct pevent *pevent, const char *comm, int pid); int pevent_register_trace_clock(struct pevent *pevent, const char *trace_clock); int pevent_register_function(struct pevent *pevent, char *name, -- GitLab