From 8dab5241d06bfc9ee141ea78c56cde5070d7460d Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Sat, 16 Jun 2007 10:16:12 -0700 Subject: Rework ptep_set_access_flags and fix sun4c Some changes done a while ago to avoid pounding on ptep_set_access_flags and update_mmu_cache in some race situations break sun4c which requires update_mmu_cache() to always be called on minor faults. This patch reworks ptep_set_access_flags() semantics, implementations and callers so that it's now responsible for returning whether an update is necessary or not (basically whether the PTE actually changed). This allow fixing the sparc implementation to always return 1 on sun4c. [akpm@linux-foundation.org: fixes, cleanups] Signed-off-by: Benjamin Herrenschmidt Cc: Hugh Dickins Cc: David Miller Cc: Mark Fortescue Acked-by: William Lee Irwin III Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-ia64/pgtable.h | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) (limited to 'include/asm-ia64') diff --git a/include/asm-ia64/pgtable.h b/include/asm-ia64/pgtable.h index 670b706411b8..6580f31b3135 100644 --- a/include/asm-ia64/pgtable.h +++ b/include/asm-ia64/pgtable.h @@ -533,16 +533,23 @@ extern void lazy_mmu_prot_update (pte_t pte); * daccess_bit in ivt.S). */ #ifdef CONFIG_SMP -# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \ -do { \ - if (__safely_writable) { \ - set_pte(__ptep, __entry); \ - flush_tlb_page(__vma, __addr); \ - } \ -} while (0) +# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \ +({ \ + int __changed = !pte_same(*(__ptep), __entry); \ + if (__changed && __safely_writable) { \ + set_pte(__ptep, __entry); \ + flush_tlb_page(__vma, __addr); \ + } \ + __changed; \ +}) #else -# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \ - ptep_establish(__vma, __addr, __ptep, __entry) +# define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \ +({ \ + int __changed = !pte_same(*(__ptep), __entry); \ + if (__changed) \ + ptep_establish(__vma, __addr, __ptep, __entry); \ + __changed; \ +}) #endif # ifdef CONFIG_VIRTUAL_MEM_MAP -- cgit v1.2.1