arm64: Remove I-cache invalidation from flush_cache_range() (ee6a7fce) · Commits · 戴 / test

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 <catalin.marinas@arm.com>

arch/arm64/include/asm/cacheflush.h

+5 −1

Original line number	Diff line number	Diff line
		@@ -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.
		*/

arch/arm64/mm/flush.c

+0 −7

Original line number	Diff line number	Diff line
		@@ -25,13 +25,6 @@
		#include <asm/cachetype.h>
		#include <asm/tlbflush.h>

		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;

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