perf/probe: verify instruction/offset in perf before adding a uprobe

This patch is to augment Srikar's perf support for uprobes patch
(https://lkml.org/lkml/2012/4/11/191) with the following features:

a. Instruction verification for user space tracing
b. Function boundary validation support to uprobes as its kernel counterpart (Commit-ID: 1c1bc922).

This will help in ensuring uprobe is placed at right location inside the intended function.

To verify instructions in perf before adding a uprobe, we need to use arch/x86/lib/insn.c. Since perf Makefile enables -Wswitch-default flag it causes build warnings/failures. Masami's patch
https://lkml.org/lkml/2012/4/12/598 addresses those warnings and it is a pre-req for this patch.

v2 addresses Masami's review comments: Rebuild insn.c and inat.c while building perf and a few other minor ones.

tools/perf/arch/x86/util/probe-event.c new file +3 -0

+
+	return ret;
+}

tools/perf/util/include/linux/string.h +1 -0

index 3b2f590..9d5eb21 100644
@@ -1 +1,2 @@
 #include <string.h>
+#include <perf.h>

tools/perf/util/probe-event.c +11 -0

index b7dec82..8f3de61 100644
@@ -2254,6 +2254,17 @@ int show_available_funcs(const char *target, struct strfilter *_filter,
 }
 
 /*
+ * Check if a given offset from start of a function is valid or not
+ */
+bool __attribute__((weak)) can_probe(char *name __used,
+					unsigned long long vaddr __used,
+					unsigned long offset __used,
+					u8 class __used)
+{
+	return true;
+}
+
+/*
  * uprobe_events only accepts address:
  * Convert function and any offset to address
  */

@@ -2307,7 +2318,16 @@ static int convert_name_to_addr(struct perf_probe_event *pev, const char *exec)
 
 	if (map->start > sym->start)
 		vaddr = map->start;

tools/perf/util/probe-event.c +1 -0

+	vaddr += pp->offset;
 	pp->offset = 0;
 
 	if (!pev->event) {

tools/perf/util/probe-event.h +2 -0

index f9f3de8..af96594 100644
@@ -137,4 +137,6 @@ extern int show_available_funcs(const char *module, struct strfilter *filter,
 /* Maximum index number of event-name postfix */
 #define MAX_EVENT_INDEX	1024
 
+extern bool can_probe(char *name, unsigned long long vaddr,
+			unsigned long offset, u8 class);
 #endif /*_PROBE_EVENT_H */

tools/perf/util/symbol.c +2 -0

index caaf75a..be58b06 100644
@@ -1184,6 +1184,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
 		goto out_close;
 	}
 
+	dso->class = gelf_getclass(elf);
 	if (gelf_getehdr(elf, &ehdr) == NULL) {
 		pr_debug("%s: cannot get elf header.\n", __func__);
 		goto out_elf_end;

@@ -1326,6 +1327,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
 				curr_dso->kernel = dso->kernel;
 				curr_dso->long_name = dso->long_name;
 				curr_dso->long_name_len = dso->long_name_len;
+				curr_dso->class = dso->class;
 				curr_map = map__new2(start, curr_dso,
 						     map->type);
 				if (curr_map == NULL) {

tools/perf/util/symbol.h +0 -0

index 9e7742c..1d0cc28 100644