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SubjectRe: [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE
Hi Stephen,

Thanks for the suggestion, I'll send a new patch.

On Thursday 10 July 2014 04:19 AM, Stephen Rothwell wrote:
> Hi Madhusudanan,
>
> On Wed, 09 Jul 2014 21:38:31 +0530 Madhusudanan Kandasamy <kmadhu@linux.vnet.ibm.com> wrote:
>>
>> diff --git a/arch/powerpc/include/asm/pte-hash64-64k.h b/arch/powerpc/include/asm/pte-hash64-64k.h
>> index d836d94..10af7f1 100644
>> --- a/arch/powerpc/include/asm/pte-hash64-64k.h
>> +++ b/arch/powerpc/include/asm/pte-hash64-64k.h
>> @@ -74,8 +74,15 @@
>> #define pte_pagesize_index(mm, addr, pte) \
>> (((pte) & _PAGE_COMBO)? MMU_PAGE_4K: MMU_PAGE_64K)
>>
>> +static inline int bad_4k_pfn(void)
>> +{
>> + WARN_ON(1);
>> + return -EINVAL;
>> +}
>> +
>> #define remap_4k_pfn(vma, addr, pfn, prot) \
>> - remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
>> - __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN))
>> + ((pfn >= (1UL << (64 - PTE_RPN_SHIFT))) ? bad_4k_pfn() : \
>> + remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
>> + __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN)))
>>
>> #endif /* __ASSEMBLY__ */
>
> WARN_ON() returns the value it is passed, so no helper is needed:
>
> #define remap_4k_pfn(vma, addr, pfn, prot) \
> - remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
> - __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN))
> + WARN_ON(((pfn >= (1UL << (64 - PTE_RPN_SHIFT)))) ? -EINVAL : \
> + remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
> + __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN)))
>



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