From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 28 Nov 2016 12:15:53 +0000 Subject: [PATCH] arm64: Remove I-cache invalidation from flush_cache_range() Message-ID: <1480335353-4030-1-git-send-email-catalin.marinas@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The flush_cache_range() function (similarly for flush_cache_page()) is called when the kernel is changing an existing VA->PA mapping range to either a new PA or to different attributes. Since ARMv8 has PIPT-like D-caches, this function does not need to perform any D-cache maintenance. The I-cache maintenance is already handled via set_pte_at() and flush_cache_range() cannot anyway guarantee that there are no cache lines left after invalidation due to the speculative loads. This patch makes flush_cache_range() a no-op. Signed-off-by: Catalin Marinas --- Cc'ing Russell as well, I think we can remove the __flush_icache_all() call in arch/arm for the VIPT (both aliasing and non-aliasing) caches since we already handle the I-cache in __sync_icache_dcache(). Any opinion? arch/arm64/include/asm/cacheflush.h | 6 +++++- arch/arm64/mm/flush.c | 7 ------- 2 files changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index e9f64ecb75ce..5a2a6ee65f65 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -65,7 +65,6 @@ * - kaddr - page address * - size - region size */ -extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end); extern void flush_icache_range(unsigned long start, unsigned long end); extern void __flush_dcache_area(void *addr, size_t len); extern void __clean_dcache_area_poc(void *addr, size_t len); @@ -82,6 +81,11 @@ static inline void flush_cache_page(struct vm_area_struct *vma, { } +static inline void flush_cache_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ +} + /* * Cache maintenance functions used by the DMA API. No to be used directly. */ diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c index 2d78d5a9b89f..554a2558c12e 100644 --- a/arch/arm64/mm/flush.c +++ b/arch/arm64/mm/flush.c @@ -25,13 +25,6 @@ #include #include -void flush_cache_range(struct vm_area_struct *vma, unsigned long start, - unsigned long end) -{ - if (vma->vm_flags & VM_EXEC) - __flush_icache_all(); -} - void sync_icache_aliases(void *kaddr, unsigned long len) { unsigned long addr = (unsigned long)kaddr;