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

Steven Rostedt rostedt at goodmis.org
Sat Apr 16 00:51:31 EST 2011

Stefan Roese <sr at 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 at denx.de> Cc: Joakim Tjernlund <joakim.tjernlund at transmode.se> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org> Cc: Steven Rostedt <rostedt at 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

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.
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