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arm64: Remove I-cache invalidation from flush_cache_range()

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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>
This commit is contained in:
Catalin Marinas 2016-11-23 18:05:52 +00:00
parent 833a9f4b5c
commit ee6a7fce8e
2 changed files with 5 additions and 8 deletions
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6
arch/arm64/include/asm/cacheflush.h
View file

@ -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.
*/

7
arch/arm64/mm/flush.c
View file

@ -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;