* [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE @ 2014-07-09 16:08 Madhusudanan Kandasamy 2014-07-09 22:49 ` Stephen Rothwell 0 siblings, 1 reply; 3+ messages in thread From: Madhusudanan Kandasamy @ 2014-07-09 16:08 UTC (permalink / raw) To: Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev; +Cc: linux-kernel 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 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE 2014-07-09 16:08 [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE Madhusudanan Kandasamy @ 2014-07-09 22:49 ` Stephen Rothwell 2014-07-10 7:46 ` Madhusudanan Kandasamy 0 siblings, 1 reply; 3+ messages in thread From: Stephen Rothwell @ 2014-07-09 22:49 UTC (permalink / raw) To: Madhusudanan Kandasamy; +Cc: Paul Mackerras, linux-kernel, linuxppc-dev [-- Attachment #1: Type: text/plain, Size: 1419 bytes --] 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))) -- Cheers, Stephen Rothwell sfr@canb.auug.org.au [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE 2014-07-09 22:49 ` Stephen Rothwell @ 2014-07-10 7:46 ` Madhusudanan Kandasamy 0 siblings, 0 replies; 3+ messages in thread From: Madhusudanan Kandasamy @ 2014-07-10 7:46 UTC (permalink / raw) To: Stephen Rothwell; +Cc: Paul Mackerras, linux-kernel, linuxppc-dev 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))) > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-07-10 7:46 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-07-09 16:08 [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE Madhusudanan Kandasamy 2014-07-09 22:49 ` Stephen Rothwell 2014-07-10 7:46 ` Madhusudanan Kandasamy
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