2 files changed, 31 insertions, 12 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a120f98c4112..5c38c81496ce 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3187,10 +3187,10 @@ static int tracing_set_tracer(const char *buf)
         }
         destroy_trace_option_files(topts);
 
-        current_trace = t;
+        current_trace = &nop_trace;
 
-        topts = create_trace_option_files(current_trace);
-        if (current_trace->use_max_tr) {
+        topts = create_trace_option_files(t);
+        if (t->use_max_tr) {
                 int cpu;
                 /* we need to make per cpu buffer sizes equivalent */
                 for_each_tracing_cpu(cpu) {
@@ -3210,6 +3210,7 @@ static int tracing_set_tracer(const char *buf)
                         goto out;
         }
 
+        current_trace = t;
         trace_branch_enable(tr);
  out:
         mutex_unlock(&trace_types_lock);
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index c7b0c6a7db09..a426f410c060 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -13,6 +13,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/pstore.h>
 #include <linux/fs.h>
 
 #include "trace.h"
@@ -74,6 +75,14 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
         preempt_enable_notrace();
 }
 
+/* Our two options */
+enum {
+        TRACE_FUNC_OPT_STACK    = 0x1,
+        TRACE_FUNC_OPT_PSTORE   = 0x2,
+};
+
+static struct tracer_flags func_flags;
+
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip)
 {
@@ -97,6 +106,12 @@ function_trace_call(unsigned long ip, unsigned long parent_ip)
         disabled = atomic_inc_return(&data->disabled);
 
         if (likely(disabled == 1)) {
+                /*
+                 * So far tracing doesn't support multiple buffers, so
+                 * we make an explicit call for now.
+                 */
+                if (unlikely(func_flags.val & TRACE_FUNC_OPT_PSTORE))
+                        pstore_ftrace_call(ip, parent_ip);
                 pc = preempt_count();
                 trace_function(tr, ip, parent_ip, flags, pc);
         }
@@ -158,15 +173,13 @@ static struct ftrace_ops trace_stack_ops __read_mostly =
         .flags = FTRACE_OPS_FL_GLOBAL,
 };
 
-/* Our two options */
-enum {
-        TRACE_FUNC_OPT_STACK = 0x1,
-};
-
 static struct tracer_opt func_opts[] = {
 #ifdef CONFIG_STACKTRACE
         { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
 #endif
+#ifdef CONFIG_PSTORE_FTRACE
+        { TRACER_OPT(func_pstore, TRACE_FUNC_OPT_PSTORE) },
+#endif
         { } /* Always set a last empty entry */
 };
 
@@ -204,10 +217,11 @@ static void tracing_stop_function_trace(void)
 
 static int func_set_flag(u32 old_flags, u32 bit, int set)
 {
-        if (bit == TRACE_FUNC_OPT_STACK) {
+        switch (bit) {
+        case TRACE_FUNC_OPT_STACK:
                 /* do nothing if already set */
                 if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
-                        return 0;
+                        break;
 
                 if (set) {
                         unregister_ftrace_function(&trace_ops);
@@ -217,10 +231,14 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
                         register_ftrace_function(&trace_ops);
                 }
 
-                return 0;
+                break;
+        case TRACE_FUNC_OPT_PSTORE:
+                break;
+        default:
+                return -EINVAL;
         }
 
-        return -EINVAL;
+        return 0;
 }
 
 static struct tracer function_trace __read_mostly =