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SubjectRe: [v2 PATCH 2/2] powerpc/8xx: use _PAGE_RO instead of _PAGE_RW

Le 18/12/2014 03:22, Scott Wood a écrit :
> On Wed, 2014-12-17 at 10:14 +0100, Christophe Leroy wrote:
>> On powerpc 8xx, in TLB entries, 0x400 bit is set to 1 for read-only pages
>> and is set to 0 for RW pages. So we should use _PAGE_RO instead of _PAGE_RW
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>
>> ---
>> v2 is a complete rework compared to v1
>>
>> arch/powerpc/include/asm/pte-8xx.h | 7 +++----
>> arch/powerpc/kernel/head_8xx.S | 3 ---
>> 2 files changed, 3 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h
>> index daa4616..4f5583e 100644
>> --- a/arch/powerpc/include/asm/pte-8xx.h
>> +++ b/arch/powerpc/include/asm/pte-8xx.h
>> @@ -46,7 +46,7 @@
>> * require a TLB exception handler change. It is assumed unused bits
>> * are always zero.
>> */
>> -#define _PAGE_RW 0x0400 /* lsb PP bits, inverted in HW */
>> +#define _PAGE_RO 0x0400 /* lsb PP bits */
> It looks like pte_update() needs to be updated to match.
>
>> #define _PAGE_USER 0x0800 /* msb PP bits */
>> /* set when neither _PAGE_USER nor _PAGE_RW are set */
> Also update this comment.
>
>> #define _PAGE_KNLRO 0x0200
>> @@ -62,9 +62,8 @@
>> #define PTE_ATOMIC_UPDATES 1
>>
>> /* We need to add _PAGE_SHARED to kernel pages */
>> -#define _PAGE_KERNEL_RO (_PAGE_SHARED | _PAGE_KNLRO)
>> -#define _PAGE_KERNEL_ROX (_PAGE_EXEC | _PAGE_KNLRO)
>> -#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
>> +#define _PAGE_KERNEL_RO (_PAGE_SHARED | _PAGE_RO | _PAGE_KNLRO)
>> +#define _PAGE_KERNEL_ROX (_PAGE_EXEC | _PAGE_RO | _PAGE_KNLRO)
>>
>> #endif /* __KERNEL__ */
>> #endif /* _ASM_POWERPC_PTE_8xx_H */
> Where did _PAGE_KERNEL_RW go?
>
>
It is already defined like this in pte-common.h:

#ifndef _PAGE_KERNEL_RW
#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
#endif


Christophe


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