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authorFrederic Weisbecker <fweisbec@gmail.com>2008-12-06 03:40:00 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-08 15:11:44 +0100
commit8b96f0119818964e4944fd1c423bf6770027d3ac (patch)
tree02b5ec86d2fe45d6935d63913b997989f9339bf4 /arch/x86
parentdecbec3838d10ecd7aabdb4c0e05aac0e5f5dc0c (diff)
tracing/function-graph-tracer: introduce __notrace_funcgraph to filter special functions
Impact: trace more functions When the function graph tracer is configured, three more files are not traced to prevent only four functions to be traced. And this impacts the normal function tracer too. arch/x86/kernel/process_64/32.c: I had crashes when I let this file traced. After some debugging, I saw that the "current" task point was changed inside__swtich_to(), ie: "write_pda(pcurrent, next_p);" inside process_64.c Since the tracer store the original return address of the function inside current, we had crashes. Only __switch_to() has to be excluded from tracing. kernel/module.c and kernel/extable.c: Because of a function used internally by the function graph tracer: __kernel_text_address() To let the other functions inside these files to be traced, this patch introduces the __notrace_funcgraph function prefix which is __notrace if function graph tracer is configured and nothing if not. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/Makefile6
-rw-r--r--arch/x86/kernel/process_32.c4
-rw-r--r--arch/x86/kernel/process_64.c4
3 files changed, 6 insertions, 8 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a3049da6198..1cad9318d21 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -14,12 +14,6 @@ CFLAGS_REMOVE_paravirt-spinlocks.o = -pg
CFLAGS_REMOVE_ftrace.o = -pg
endif
-ifdef CONFIG_FUNCTION_GRAPH_TRACER
-# Don't trace __switch_to() but let it for function tracer
-CFLAGS_REMOVE_process_32.o = -pg
-CFLAGS_REMOVE_process_64.o = -pg
-endif
-
#
# vsyscalls (which work on the user stack) should have
# no stack-protector checks:
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0a1302fe6d4..24c2276aa45 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -38,6 +38,7 @@
#include <linux/percpu.h>
#include <linux/prctl.h>
#include <linux/dmi.h>
+#include <linux/ftrace.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
@@ -548,7 +549,8 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
* the task-switch, and shows up in ret_from_fork in entry.S,
* for example.
*/
-struct task_struct * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
+__notrace_funcgraph struct task_struct *
+__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
{
struct thread_struct *prev = &prev_p->thread,
*next = &next_p->thread;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c958120fb1b..fbb321d53d3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -39,6 +39,7 @@
#include <linux/prctl.h>
#include <linux/uaccess.h>
#include <linux/io.h>
+#include <linux/ftrace.h>
#include <asm/pgtable.h>
#include <asm/system.h>
@@ -551,8 +552,9 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
* - could test fs/gs bitsliced
*
* Kprobes not supported here. Set the probe on schedule instead.
+ * Function graph tracer not supported too.
*/
-struct task_struct *
+__notrace_funcgraph struct task_struct *
__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
{
struct thread_struct *prev = &prev_p->thread;