perf tools: Add machine__kernel_ip()

Add a function to determine if an address is in the kernel.  This is
based on the kernel function kernel_ip().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1408129739-17368-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.c

@@ -784,9 +784,9 @@ try_again:
 		 * "[vdso]" dso, but for now lets use the old trick of looking
 		 * in the whole kernel symbol list.
 		 */
-		if ((long long)al->addr < 0 &&
-		    cpumode == PERF_RECORD_MISC_USER &&
-		    machine && mg != &machine->kmaps) {
+		if (cpumode == PERF_RECORD_MISC_USER && machine &&
+		    mg != &machine->kmaps &&
+		    machine__kernel_ip(machine, al->addr)) {
 			mg = &machine->kmaps;
 			load_map = true;
 			goto try_again;

tools/perf/util/machine.c

@@ -32,6 +32,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 	machine->symbol_filter = NULL;
 	machine->id_hdr_size = 0;
 	machine->comm_exec = false;
+	machine->kernel_start = 0;
 
 	machine->root_dir = strdup(root_dir);
 	if (machine->root_dir == NULL)
@@ -1559,3 +1560,25 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 
 	return 0;
 }
+
+int machine__get_kernel_start(struct machine *machine)
+{
+	struct map *map = machine__kernel_map(machine, MAP__FUNCTION);
+	int err = 0;
+
+	/*
+	 * The only addresses above 2^63 are kernel addresses of a 64-bit
+	 * kernel.  Note that addresses are unsigned so that on a 32-bit system
+	 * all addresses including kernel addresses are less than 2^32.  In
+	 * that case (32-bit system), if the kernel mapping is unknown, all
+	 * addresses will be assumed to be in user space - see
+	 * machine__kernel_ip().
+	 */
+	machine->kernel_start = 1ULL << 63;
+	if (map) {
+		err = map__load(map, machine->symbol_filter);
+		if (map->start)
+			machine->kernel_start = map->start;
+	}
+	return err;
+}

tools/perf/util/machine.h

@@ -36,6 +36,7 @@ struct machine {
 	struct list_head  kernel_dsos;
 	struct map_groups kmaps;
 	struct map	  *vmlinux_maps[MAP__NR_TYPES];
+	u64		  kernel_start;
 	symbol_filter_t	  symbol_filter;
 	pid_t		  *current_tid;
 };
@@ -46,6 +47,22 @@ struct map *machine__kernel_map(struct machine *machine, enum map_type type)
 	return machine->vmlinux_maps[type];
 }
 
+int machine__get_kernel_start(struct machine *machine);
+
+static inline u64 machine__kernel_start(struct machine *machine)
+{
+	if (!machine->kernel_start)
+		machine__get_kernel_start(machine);
+	return machine->kernel_start;
+}
+
+static inline bool machine__kernel_ip(struct machine *machine, u64 ip)
+{
+	u64 kernel_start = machine__kernel_start(machine);
+
+	return ip >= kernel_start;
+}
+
 struct thread *machine__find_thread(struct machine *machine, pid_t pid,
 				    pid_t tid);
 struct comm *machine__thread_exec_comm(struct machine *machine,