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 <redacted>
---
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
Hi Madhusudanan,
On Wed, 09 Jul 2014 21:38:31 +0530 Madhusudanan Kandasamy [off-list ref] wrote:
quoted hunk
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
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 [off-list ref] wrote:
quoted
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)))