On SMP systems, there is a small chance of a PTE becoming visible to a different CPU before the current cache maintenance operations in update_mmu_cache(). To avoid this, cache maintenance must be handled in set_pte_at() (similar to IA-64 and PowerPC). This patch provides a unified VIPT cache handling mechanism and implements the __sync_icache_dcache() function for ARMv6 onwards architectures. It is called from set_pte_at() and replaces the update_mmu_cache(). The latter is still used on VIVT hardware where a vm_area_struct is required. Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Tested-by: Rabin Vincent <rabin.vincent@xxxxxxxxxxxxxx> Cc: Nicolas Pitre <nico@xxxxxxxxxx> --- arch/arm/include/asm/pgtable.h | 26 +++++++++++++++++++++++--- arch/arm/include/asm/tlbflush.h | 10 +++++++++- arch/arm/mm/fault-armv.c | 4 ++-- arch/arm/mm/flush.c | 30 ++++++++++++++++++++++++++++++ 4 files changed, 64 insertions(+), 6 deletions(-) diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index ab68cf1..42e694f 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -278,9 +278,24 @@ extern struct page *empty_zero_page; #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) -#define set_pte_at(mm,addr,ptep,pteval) do { \ - set_pte_ext(ptep, pteval, (addr) >= TASK_SIZE ? 0 : PTE_EXT_NG); \ - } while (0) +#if __LINUX_ARM_ARCH__ < 6 +static inline void __sync_icache_dcache(pte_t pteval) +{ +} +#else +extern void __sync_icache_dcache(pte_t pteval); +#endif + +static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval) +{ + if (addr >= TASK_SIZE) + set_pte_ext(ptep, pteval, 0); + else { + __sync_icache_dcache(pteval); + set_pte_ext(ptep, pteval, PTE_EXT_NG); + } +} /* * The following only work if pte_present() is true. @@ -290,8 +305,13 @@ extern struct page *empty_zero_page; #define pte_write(pte) (pte_val(pte) & L_PTE_WRITE) #define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) #define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) +#define pte_exec(pte) (pte_val(pte) & L_PTE_EXEC) #define pte_special(pte) (0) +#define pte_present_user(pte) \ + ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \ + (L_PTE_PRESENT | L_PTE_USER)) + #define PTE_BIT_FUNC(fn,op) \ static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h index 40a7092..8ec4775 100644 --- a/arch/arm/include/asm/tlbflush.h +++ b/arch/arm/include/asm/tlbflush.h @@ -554,10 +554,18 @@ extern void flush_tlb_kernel_range(unsigned long start, unsigned long end); /* * If PG_dcache_clean is not set for the page, we need to ensure that any * cache entries for the kernels virtual memory range are written - * back to the page. + * back to the page. On ARMv6 and later, the cache coherency is handled via + * the set_pte_at() function. */ +#if __LINUX_ARM_ARCH__ < 6 extern void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep); +#else +static inline void update_mmu_cache(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +} +#endif #endif diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index 58846cb..8440d95 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -28,6 +28,7 @@ static unsigned long shared_pte_mask = L_PTE_MT_BUFFERABLE; +#if __LINUX_ARM_ARCH__ < 6 /* * We take the easy way out of this problem - we make the * PTE uncacheable. However, we leave the write buffer on. @@ -168,10 +169,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, return; mapping = page_mapping(page); -#ifndef CONFIG_SMP if (!test_and_set_bit(PG_dcache_clean, &page->flags)) __flush_dcache_page(mapping, page); -#endif if (mapping) { if (cache_is_vivt()) make_coherent(mapping, vma, addr, ptep, pfn); @@ -179,6 +178,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, __flush_icache_all(); } } +#endif /* __LINUX_ARM_ARCH__ < 6 */ /* * Check whether the write buffer has physical address aliasing diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index b4efce9..dd5b012 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -215,6 +215,36 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p flush_dcache_mmap_unlock(mapping); } +#if __LINUX_ARM_ARCH__ >= 6 +void __sync_icache_dcache(pte_t pteval) +{ + unsigned long pfn; + struct page *page; + struct address_space *mapping; + + if (!pte_present_user(pteval)) + return; + if (cache_is_vipt_nonaliasing() && !pte_exec(pteval)) + /* only flush non-aliasing VIPT caches for exec mappings */ + return; + pfn = pte_pfn(pteval); + if (!pfn_valid(pfn)) + return; + + page = pfn_to_page(pfn); + if (cache_is_vipt_aliasing()) + mapping = page_mapping(page); + else + mapping = NULL; + + if (!test_and_set_bit(PG_dcache_clean, &page->flags)) + __flush_dcache_page(mapping, page); + /* pte_exec() already checked above for non-aliasing VIPT cache */ + if (cache_is_vipt_nonaliasing() || pte_exec(pteval)) + __flush_icache_all(); +} +#endif + /* * Ensure cache coherency between kernel mapping and userspace mapping * of this page. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html