2 files changed, 28 insertions, 15 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index d1d25f6a5e24..297ca3db6b4a 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -268,7 +268,10 @@ struct perf_event_attr {
                                 exclude_host   :  1, /* don't count in host   */
                                 exclude_guest  :  1, /* don't count in guest  */
 
-                                __reserved_1   : 43;
+                                exclude_callchain_kernel : 1, /* exclude kernel callchains */
+                                exclude_callchain_user   : 1, /* exclude user callchains */
+
+                                __reserved_1   : 41;
 
         union {
                 __u32           wakeup_events;    /* wakeup every n events */
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 98d4597f43d6..c77206184b8b 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -159,6 +159,11 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs)
         int rctx;
         struct perf_callchain_entry *entry;
 
+        int kernel = !event->attr.exclude_callchain_kernel;
+        int user   = !event->attr.exclude_callchain_user;
+
+        if (!kernel && !user)
+                return NULL;
 
         entry = get_callchain_entry(&rctx);
         if (rctx == -1)
@@ -169,24 +174,29 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs)
 
         entry->nr = 0;
 
-        if (!user_mode(regs)) {
+        if (kernel && !user_mode(regs)) {
                 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
                 perf_callchain_kernel(entry, regs);
-                if (current->mm)
-                        regs = task_pt_regs(current);
-                else
-                        regs = NULL;
         }
 
-        if (regs) {
-                /*
-                 * Disallow cross-task user callchains.
-                 */
-                if (event->ctx->task && event->ctx->task != current)
-                        goto exit_put;
-
-                perf_callchain_store(entry, PERF_CONTEXT_USER);
-                perf_callchain_user(entry, regs);
+        if (user) {
+                if (!user_mode(regs)) {
+                        if  (current->mm)
+                                regs = task_pt_regs(current);
+                        else
+                                regs = NULL;
+                }
+
+                if (regs) {
+                        /*
+                         * Disallow cross-task user callchains.
+                         */
+                        if (event->ctx->task && event->ctx->task != current)
+                                goto exit_put;
+
+                        perf_callchain_store(entry, PERF_CONTEXT_USER);
+                        perf_callchain_user(entry, regs);
+                }
         }
 
 exit_put: