| From foo@baz Thu Mar 22 14:57:32 CET 2018 |
| From: Abel Vesa <abelvesa@linux.com> |
| Date: Mon, 3 Apr 2017 23:58:54 +0100 |
| Subject: ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER |
| |
| From: Abel Vesa <abelvesa@linux.com> |
| |
| |
| [ Upstream commit 6f05d0761af612e04572ba4d65b4c0274a88444f ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/arm/kernel/ftrace.c | 11 ++++++----- |
| 1 file changed, 6 insertions(+), 5 deletions(-) |
| |
| --- 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; |
