[PATCH] powerpc: Fix oops when loading modules

[PATCH] powerpc: Fix oops when loading modules

[Paul Mackerras]

This fixes a problem reported by Sean MacLennan where loading any
module would cause an oops.  We weren't marking the pages containing
the module text as having hardware execute permission, due to a bug
introduced in commit 8d1cf34e ("powerpc/mm: Tweak PTE bit combination
definitions"), hence trying to execute the module text caused an
exception on processors that support hardware execute permission.

This adds _PAGE_HWEXEC to the definitions of PAGE_KERNEL_X and
PAGE_KERNEL_ROX to fix this problem.

Reported-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/include/asm/pte-common.h |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index d9740e8..a7e210b 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -151,9 +151,11 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
 				 _PAGE_NO_CACHE)
 #define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
 				 _PAGE_NO_CACHE | _PAGE_GUARDED)
-#define PAGE_KERNEL_X	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW | _PAGE_EXEC)
+#define PAGE_KERNEL_X	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW | _PAGE_EXEC | \
+				 _PAGE_HWEXEC)
 #define PAGE_KERNEL_RO	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
-#define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO | _PAGE_EXEC)
+#define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO | _PAGE_EXEC | \
+				 _PAGE_HWEXEC)
 
 /* Protection used for kernel text. We want the debuggers to be able to
  * set breakpoints anywhere, so don't write protect the kernel text

Re: [PATCH] powerpc: Fix oops when loading modules

[Geert Uytterhoeven]

On Tue, 7 Apr 2009, Paul Mackerras wrote:
> This fixes a problem reported by Sean MacLennan where loading any
> module would cause an oops.  We weren't marking the pages containing
> the module text as having hardware execute permission, due to a bug
> introduced in commit 8d1cf34e ("powerpc/mm: Tweak PTE bit combination
> definitions"), hence trying to execute the module text caused an
> exception on processors that support hardware execute permission.
> 
> This adds _PAGE_HWEXEC to the definitions of PAGE_KERNEL_X and
> PAGE_KERNEL_ROX to fix this problem.
> 
> Reported-by: Sean MacLennan <smaclennan@pikatech.com>
> Signed-off-by: Paul Mackerras <paulus@samba.org>

Tested-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
(on Sequoia)

With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone:    +32 (0)2 700 8453
Fax:      +32 (0)2 700 8622
E-mail:   Geert.Uytterhoeven@sonycom.com
Internet: http://www.sony-europe.com/

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