From 0a28714c53fd4f7aea709be7577dfbe0095c8c3e Mon Sep 17 00:00:00 2001 From: Ashok Kumar Date: Thu, 17 Dec 2015 01:38:32 -0800 Subject: [PATCH] arm64: Use PoU cache instr for I/D coherency In systems with three levels of cache(PoU at L1 and PoC at L3), PoC cache flush instructions flushes L2 and L3 caches which could affect performance. For cache flushes for I and D coherency, PoU should suffice. So changing all I and D coherency related cache flushes to PoU. Introduced a new __clean_dcache_area_pou API for dcache flush till PoU and provided a common macro for __flush_dcache_area and __clean_dcache_area_pou. Also, now in __sync_icache_dcache, icache invalidation for non-aliasing VIPT icache is done only for that particular page instead of the earlier __flush_icache_all. Reviewed-by: Catalin Marinas Reviewed-by: Mark Rutland Signed-off-by: Ashok Kumar Signed-off-by: Will Deacon --- arch/arm64/include/asm/cacheflush.h | 1 + arch/arm64/mm/cache.S | 28 ++++++++++++++---------- arch/arm64/mm/flush.c | 33 ++++++++++++++++------------- arch/arm64/mm/proc-macros.S | 22 +++++++++++++++++++ 4 files changed, 58 insertions(+), 26 deletions(-) diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index 54efedaf331f..7fc294c3bc5b 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -68,6 +68,7 @@ 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_pou(void *addr, size_t len); extern long __flush_cache_user_range(unsigned long start, unsigned long end); static inline void flush_cache_mm(struct mm_struct *mm) diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index cfa44a6adc0a..6df07069a025 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -81,25 +81,31 @@ ENDPROC(__flush_cache_user_range) /* * __flush_dcache_area(kaddr, size) * - * Ensure that the data held in the page kaddr is written back to the - * page in question. + * Ensure that any D-cache lines for the interval [kaddr, kaddr+size) + * are cleaned and invalidated to the PoC. * * - kaddr - kernel address * - size - size in question */ ENTRY(__flush_dcache_area) - dcache_line_size x2, x3 - add x1, x0, x1 - sub x3, x2, #1 - bic x0, x0, x3 -1: dc civac, x0 // clean & invalidate D line / unified line - add x0, x0, x2 - cmp x0, x1 - b.lo 1b - dsb sy + dcache_by_line_op civac, sy, x0, x1, x2, x3 ret ENDPIPROC(__flush_dcache_area) +/* + * __clean_dcache_area_pou(kaddr, size) + * + * Ensure that any D-cache lines for the interval [kaddr, kaddr+size) + * are cleaned to the PoU. + * + * - kaddr - kernel address + * - size - size in question + */ +ENTRY(__clean_dcache_area_pou) + dcache_by_line_op cvau, ish, x0, x1, x2, x3 + ret +ENDPROC(__clean_dcache_area_pou) + /* * __inval_cache_range(start, end) * - start - start address of region diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c index c26b804015e8..46649d6e6c5a 100644 --- a/arch/arm64/mm/flush.c +++ b/arch/arm64/mm/flush.c @@ -34,19 +34,24 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, __flush_icache_all(); } +static void sync_icache_aliases(void *kaddr, unsigned long len) +{ + unsigned long addr = (unsigned long)kaddr; + + if (icache_is_aliasing()) { + __clean_dcache_area_pou(kaddr, len); + __flush_icache_all(); + } else { + flush_icache_range(addr, addr + len); + } +} + static void flush_ptrace_access(struct vm_area_struct *vma, struct page *page, unsigned long uaddr, void *kaddr, unsigned long len) { - if (vma->vm_flags & VM_EXEC) { - unsigned long addr = (unsigned long)kaddr; - if (icache_is_aliasing()) { - __flush_dcache_area(kaddr, len); - __flush_icache_all(); - } else { - flush_icache_range(addr, addr + len); - } - } + if (vma->vm_flags & VM_EXEC) + sync_icache_aliases(kaddr, len); } /* @@ -74,13 +79,11 @@ void __sync_icache_dcache(pte_t pte, unsigned long addr) if (!page_mapping(page)) return; - if (!test_and_set_bit(PG_dcache_clean, &page->flags)) { - __flush_dcache_area(page_address(page), - PAGE_SIZE << compound_order(page)); + if (!test_and_set_bit(PG_dcache_clean, &page->flags)) + sync_icache_aliases(page_address(page), + PAGE_SIZE << compound_order(page)); + else if (icache_is_aivivt()) __flush_icache_all(); - } else if (icache_is_aivivt()) { - __flush_icache_all(); - } } /* diff --git a/arch/arm64/mm/proc-macros.S b/arch/arm64/mm/proc-macros.S index 4c4d93c4bf65..146bd99a7532 100644 --- a/arch/arm64/mm/proc-macros.S +++ b/arch/arm64/mm/proc-macros.S @@ -62,3 +62,25 @@ bfi \valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH #endif .endm + +/* + * Macro to perform a data cache maintenance for the interval + * [kaddr, kaddr + size) + * + * op: operation passed to dc instruction + * domain: domain used in dsb instruciton + * kaddr: starting virtual address of the region + * size: size of the region + * Corrupts: kaddr, size, tmp1, tmp2 + */ + .macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2 + dcache_line_size \tmp1, \tmp2 + add \size, \kaddr, \size + sub \tmp2, \tmp1, #1 + bic \kaddr, \kaddr, \tmp2 +9998: dc \op, \kaddr + add \kaddr, \kaddr, \tmp1 + cmp \kaddr, \size + b.lo 9998b + dsb \domain + .endm -- 2.20.1