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authorAbel Vesa <abelvesa@linux.com>2017-04-03 23:58:54 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2017-04-20 11:19:43 +0100
commit6f05d0761af612e04572ba4d65b4c0274a88444f (patch)
tree2171d2bc5260bd2444d82214f7cdf5c1ecb1eb01 /arch/arm
parentb089c31c519c3906c14801b6ec483e18a5152a50 (diff)
ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER
The support for dynamic ftrace with CONFIG_DEBUG_RODATA involves overriding the weak arch_ftrace_update_code() with a variant which makes the kernel text writable around the patching. This override was however added under the CONFIG_OLD_MCOUNT ifdef, and CONFIG_OLD_MCOUNT is only enabled if frame pointers are enabled. This leads to non-functional dynamic ftrace (ftrace triggers a WARN_ON()) when CONFIG_DEBUG_RODATA is enabled and CONFIG_FRAME_POINTER is not. Move the override out of that ifdef and into the CONFIG_DYNAMIC_FTRACE ifdef where it belongs. Fixes: 80d6b0c2eed2a ("ARM: mm: allow text and rodata sections to be read-only") Suggested-by: Nicolai Stange <nicstange@gmail.com> Suggested-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Abel Vesa <abelvesa@gmail.com> Acked-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/kernel/ftrace.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 3f1759411d51..414e60ed0257 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -29,11 +29,6 @@
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
-#ifdef CONFIG_OLD_MCOUNT
-#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
-#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
-
-#define OLD_NOP 0xe1a00000 /* mov r0, r0 */
static int __ftrace_modify_code(void *data)
{
@@ -51,6 +46,12 @@ void arch_ftrace_update_code(int command)
stop_machine(__ftrace_modify_code, &command, NULL);
}
+#ifdef CONFIG_OLD_MCOUNT
+#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
+#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
+
+#define OLD_NOP 0xe1a00000 /* mov r0, r0 */
+
static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
{
return rec->arch.old_mcount ? OLD_NOP : NOP;