Messages in this thread Patch in this message | | | Date | Wed, 09 Jul 2014 21:38:31 +0530 | From | Madhusudanan Kandasamy <> | Subject | [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE |
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remap_4k_pfn() silently truncates upper bits of input 4K PFN if it cannot be contained in PTE. This leads invalid memory mapping and could result in a system crash when the memory is accessed. This patch fails remap_4k_pfn() and returns -EINVAL if the input 4K PFN cannot be contained in PTE. Used a helper inline function in the failure case so that the remap_4k_pfn() macro can still be used in expression contexts.
Signed-off-by: Madhusudanan Kandasamy <kmadhu@linux.vnet.ibm.com> --- arch/powerpc/include/asm/pte-hash64-64k.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
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__ */ -- 2.0.1
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