From 3e87974dec5ec25a8a4852d9292db6be659164e6 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Wed, 22 May 2013 18:38:10 +0530 Subject: [PATCH] ARC: Brown paper bag bug in macro for checking cache color The VM_EXEC check in update_mmu_cache() was getting optimized away because of a stupid error in definition of macro addr_not_cache_congruent() The intention was to have the equivalent of following: if (a || (1 ? b : 0)) but we ended up with following: if (a || 1 ? b : 0) And because precedence of '||' is more that that of '?', gcc was optimizing away evaluation of Nasty Repercussions: 1. For non-aliasing configs it would mean some extraneous dcache flushes for non-code pages if U/K mappings were not congruent. 2. For aliasing config, some needed dcache flush for code pages might be missed if U/K mappings were congruent. Signed-off-by: Vineet Gupta --- arch/arc/include/asm/cacheflush.h | 4 +++- arch/arc/mm/tlb.c | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arc/include/asm/cacheflush.h b/arch/arc/include/asm/cacheflush.h index 9f841af4109..7d819749478 100644 --- a/arch/arc/include/asm/cacheflush.h +++ b/arch/arc/include/asm/cacheflush.h @@ -99,8 +99,10 @@ static inline int cache_is_vipt_aliasing(void) * checks if two addresses (after page aligning) index into same cache set */ #define addr_not_cache_congruent(addr1, addr2) \ +({ \ cache_is_vipt_aliasing() ? \ - (CACHE_COLOR(addr1) != CACHE_COLOR(addr2)) : 0 \ + (CACHE_COLOR(addr1) != CACHE_COLOR(addr2)) : 0; \ +}) #define copy_to_user_page(vma, page, vaddr, dst, src, len) \ do { \ diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index 066145b5f34..fe1c5a073af 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -444,7 +444,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned, * so userspace sees the right data. * (Avoids the flush for Non-exec + congruent mapping case) */ - if (vma->vm_flags & VM_EXEC || addr_not_cache_congruent(paddr, vaddr)) { + if ((vma->vm_flags & VM_EXEC) || + addr_not_cache_congruent(paddr, vaddr)) { struct page *page = pfn_to_page(pte_pfn(*ptep)); int dirty = test_and_clear_bit(PG_arch_1, &page->flags); -- 2.41.0