1 files changed, 76 insertions, 40 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 85e517e84f50..3f8dc1ce8b9c 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -13,33 +13,83 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/slab.h>
 #include <linux/fs.h>
 
 #include "trace.h"
 
-/* function tracing enabled */
-static int                      ftrace_function_enabled;
+static void tracing_start_function_trace(struct trace_array *tr);
+static void tracing_stop_function_trace(struct trace_array *tr);
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip,
+                    struct ftrace_ops *op, struct pt_regs *pt_regs);
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+                          struct ftrace_ops *op, struct pt_regs *pt_regs);
+static struct ftrace_ops trace_ops;
+static struct ftrace_ops trace_stack_ops;
+static struct tracer_flags func_flags;
+
+/* Our option */
+enum {
+        TRACE_FUNC_OPT_STACK    = 0x1,
+};
+
+static int allocate_ftrace_ops(struct trace_array *tr)
+{
+        struct ftrace_ops *ops;
 
-static struct trace_array       *func_trace;
+        ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+        if (!ops)
+                return -ENOMEM;
 
-static void tracing_start_function_trace(void);
-static void tracing_stop_function_trace(void);
+        /* Currently only the non stack verision is supported */
+        ops->func = function_trace_call;
+        ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
+
+        tr->ops = ops;
+        ops->private = tr;
+        return 0;
+}
 
 static int function_trace_init(struct trace_array *tr)
 {
-        func_trace = tr;
+        struct ftrace_ops *ops;
+        int ret;
+
+        if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+                /* There's only one global tr */
+                if (!trace_ops.private) {
+                        trace_ops.private = tr;
+                        trace_stack_ops.private = tr;
+                }
+
+                if (func_flags.val & TRACE_FUNC_OPT_STACK)
+                        ops = &trace_stack_ops;
+                else
+                        ops = &trace_ops;
+                tr->ops = ops;
+        } else {
+                ret = allocate_ftrace_ops(tr);
+                if (ret)
+                        return ret;
+        }
+
         tr->trace_buffer.cpu = get_cpu();
         put_cpu();
 
         tracing_start_cmdline_record();
-        tracing_start_function_trace();
+        tracing_start_function_trace(tr);
         return 0;
 }
 
 static void function_trace_reset(struct trace_array *tr)
 {
-        tracing_stop_function_trace();
+        tracing_stop_function_trace(tr);
         tracing_stop_cmdline_record();
+        if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
+                kfree(tr->ops);
+        tr->ops = NULL;
 }
 
 static void function_trace_start(struct trace_array *tr)
@@ -47,25 +97,18 @@ static void function_trace_start(struct trace_array *tr)
         tracing_reset_online_cpus(&tr->trace_buffer);
 }
 
-/* Our option */
-enum {
-        TRACE_FUNC_OPT_STACK    = 0x1,
-};
-
-static struct tracer_flags func_flags;
-
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip,
                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
-        struct trace_array *tr = func_trace;
+        struct trace_array *tr = op->private;
         struct trace_array_cpu *data;
         unsigned long flags;
         int bit;
         int cpu;
         int pc;
 
-        if (unlikely(!ftrace_function_enabled))
+        if (unlikely(!tr->function_enabled))
                 return;
 
         pc = preempt_count();
@@ -91,14 +134,14 @@ static void
 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
                           struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
-        struct trace_array *tr = func_trace;
+        struct trace_array *tr = op->private;
         struct trace_array_cpu *data;
         unsigned long flags;
         long disabled;
         int cpu;
         int pc;
 
-        if (unlikely(!ftrace_function_enabled))
+        if (unlikely(!tr->function_enabled))
                 return;
 
         /*
@@ -128,7 +171,6 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
         local_irq_restore(flags);
 }
 
-
 static struct ftrace_ops trace_ops __read_mostly =
 {
         .func = function_trace_call,
@@ -153,26 +195,17 @@ static struct tracer_flags func_flags = {
         .opts = func_opts
 };
 
-static void tracing_start_function_trace(void)
+static void tracing_start_function_trace(struct trace_array *tr)
 {
-        ftrace_function_enabled = 0;
-
-        if (func_flags.val & TRACE_FUNC_OPT_STACK)
-                register_ftrace_function(&trace_stack_ops);
-        else
-                register_ftrace_function(&trace_ops);
-
-        ftrace_function_enabled = 1;
+        tr->function_enabled = 0;
+        register_ftrace_function(tr->ops);
+        tr->function_enabled = 1;
 }
 
-static void tracing_stop_function_trace(void)
+static void tracing_stop_function_trace(struct trace_array *tr)
 {
-        ftrace_function_enabled = 0;
-
-        if (func_flags.val & TRACE_FUNC_OPT_STACK)
-                unregister_ftrace_function(&trace_stack_ops);
-        else
-                unregister_ftrace_function(&trace_ops);
+        tr->function_enabled = 0;
+        unregister_ftrace_function(tr->ops);
 }
 
 static int
@@ -184,12 +217,14 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
                 if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
                         break;
 
+                unregister_ftrace_function(tr->ops);
+
                 if (set) {
-                        unregister_ftrace_function(&trace_ops);
-                        register_ftrace_function(&trace_stack_ops);
+                        tr->ops = &trace_stack_ops;
+                        register_ftrace_function(tr->ops);
                 } else {
-                        unregister_ftrace_function(&trace_stack_ops);
-                        register_ftrace_function(&trace_ops);
+                        tr->ops = &trace_ops;
+                        register_ftrace_function(tr->ops);
                 }
 
                 break;
@@ -209,6 +244,7 @@ static struct tracer function_trace __tracer_data =
         .wait_pipe      = poll_wait_pipe,
         .flags          = &func_flags,
         .set_flag       = func_set_flag,
+        .allow_instances = true,
 #ifdef CONFIG_FTRACE_SELFTEST
         .selftest       = trace_selftest_startup_function,
 #endif