Messages in this thread Patch in this message | | | Subject | pte_modify fix backport... | From | Daniel J Blueman <> | Date | Thu, 05 Aug 2004 12:13:51 +0100 |
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This patch [1] corrects the behaviour of pte_modify() on ia64 to not clear page protection flags it shouldn't touch.
Without this patch, it clears the uncacheable flag on UC memory regions, which can cause MCAs with device I/O.
It was taken into 2.6.0 a while ago, but is yet to be included in 2.4 - the patch here is rediffed against 2.4.26-rc5.
Is there chance of it being taken in?
--- [1]
diff -durN linux-2.4.26-rc5-orig/include/asm-ia64/pgtable.h linux-2.4.26-rc5-patched/include/asm-ia64/pgtable.h --- linux-2.4.26-rc5-orig/include/asm-ia64/pgtable.h 2004-02-18 13:36:32.000000000 +0000 +++ linux-2.4.26-rc5-patched/include/asm-ia64/pgtable.h 2004-08-05 11:46:03.000000000 +0100 @@ -60,7 +60,8 @@ #define _PAGE_PROTNONE (__IA64_UL(1) << 63) #define _PFN_MASK _PAGE_PPN_MASK -#define _PAGE_CHG_MASK (_PFN_MASK | _PAGE_A | _PAGE_D) +/* Mask of bits which may be changed by pte_modify(); the odd bits are there for _PAGE_PROTNONE */ +#define _PAGE_CHG_MASK (_PAGE_P | _PAGE_PROTNONE | _PAGE_PL_MASK | _PAGE_AR_MASK | _PAGE_ED) #define _PAGE_SIZE_4K 12 #define _PAGE_SIZE_8K 13 @@ -216,7 +217,7 @@ ({ pte_t __pte; pte_val(__pte) = physpage + pgprot_val(pgprot); __pte; }) #define pte_modify(_pte, newprot) \ - (__pte((pte_val(_pte) & _PAGE_CHG_MASK) | pgprot_val(newprot))) + (__pte((pte_val(_pte) & ~_PAGE_CHG_MASK) | (pgprot_val(newprot) & _PAGE_CHG_MASK))) #define page_pte_prot(page,prot) mk_pte(page, prot) #define page_pte(page) page_pte_prot(page, __pgprot(0)) -- Daniel J Blueman Software Engineer, Quadrics Ltd
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