From: Madhusudanan Kandasamy <kmadhu@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
Stephen Rothwell <sfr@canb.auug.org.au>
Subject: [PATCH V2] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE
Date: Thu, 10 Jul 2014 14:12:19 +0530 [thread overview]
Message-ID: <53BE51EB.5090208@linux.vnet.ibm.com> (raw)
V2 : Rewritten to avoid helper function as suggested by Stephen Rothwell.
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.
Signed-off-by: Madhusudanan Kandasamy <kmadhu@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/pte-hash64-64k.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/pte-hash64-64k.h b/arch/powerpc/include/asm/pte-hash64-64k.h
index d836d94..b5178e4 100644
--- a/arch/powerpc/include/asm/pte-hash64-64k.h
+++ b/arch/powerpc/include/asm/pte-hash64-64k.h
@@ -75,7 +75,8 @@
(((pte) & _PAGE_COMBO)? MMU_PAGE_4K: MMU_PAGE_64K)
#define remap_4k_pfn(vma, addr, pfn, prot) \
- remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
+ WARN_ON((pfn >= (1UL << (64 - PTE_RPN_SHIFT)))) ? -EINVAL : \
+ remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \
__pgprot(pgprot_val((prot)) | _PAGE_4K_PFN))
#endif /* __ASSEMBLY__ */
--
2.0.1
next reply other threads:[~2014-07-10 8:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-10 8:42 Madhusudanan Kandasamy [this message]
2014-07-10 13:59 ` [PATCH V2] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE Brian W Hart
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