[PATCH] powerpc: Don't write protect kernel text with CONFIG_DYNAMIC_FTRACE enabled

[PATCH] powerpc: Don't write protect kernel text with CONFIG_DYNAMIC_FTRACE enabled

[Stefan Roese]

This problem was noticed on an MPC855T platform. Ftrace did oops
when trying to write to the kernel text segment.

Many thanks to Joakim for finding the root cause of this problem.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 arch/powerpc/include/asm/pte-common.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index 811f04a..8d1569c 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -162,7 +162,7 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
  * on platforms where such control is possible.
  */
 #if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\
-	defined(CONFIG_KPROBES)
+	defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE)
 #define PAGE_KERNEL_TEXT	PAGE_KERNEL_X
 #else
 #define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX
-- 
1.7.4.4

Re: [PATCH] powerpc: Don't write protect kernel text with CONFIG_DYNAMIC_FTRACE enabled

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1270 bytes --]

Stefan Roese <sr@denx.de> wrote:

This problem was noticed on an MPC855T platform. Ftrace did oops when trying to write to the kernel text segment. Many thanks to Joakim for finding the root cause of this problem. Signed-off-by: Stefan Roese <sr@denx.de> Cc: Joakim Tjernlund <joakim.tjernlund@transmode.se> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Steven Rostedt <rostedt@goodmis.org> --- arch/powerpc/include/asm/pte-common.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h index 811f04a..8d1569c 100644 --- a/arch/powerpc/include/asm/pte-common.h +++ b/arch/powerpc/include/asm/pte-common.h @@ -162,7 +162,7 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void); * on platforms where such control is possible. */ #if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\ -	defined(CONFIG_KPROBES) +	defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE) #define
PAGE_KERNEL_TEXT	PAGE_KERNEL_X #else #define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX -- 1.7.4.4 


This is fine for a work around but you should take a look at what x86 does for this.

-- Steve 
-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.

[-- Attachment #2: Type: text/html, Size: 1651 bytes --]