Commit-ID: c38116bb940ae37f51fccd315b420ee5961dcb76 Gitweb: https://git.kernel.org/tip/c38116bb940ae37f51fccd315b420ee5961dcb76 Author: Peter Zijlstra <[email protected]> AuthorDate: Mon, 3 Dec 2018 18:03:52 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 17 Dec 2018 18:54:29 +0100
x86/mm/cpa: Better use CLFLUSHOPT Currently we issue an MFENCE before and after flushing a range. This means that if we flush a bunch of single page ranges -- like with the cpa array, we issue a whole bunch of superfluous MFENCEs. Reorgainze the code a little to avoid this. [ mingo: capitalize instructions, tweak changelog and comments. ] Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/mm/pageattr.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 85ef53b86fa0..7d05149995dc 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -251,15 +251,7 @@ static unsigned long __cpa_addr(struct cpa_data *cpa, unsigned long idx) * Flushing functions */ -/** - * clflush_cache_range - flush a cache range with clflush - * @vaddr: virtual start address - * @size: number of bytes to flush - * - * clflushopt is an unordered instruction which needs fencing with mfence or - * sfence to avoid ordering issues. - */ -void clflush_cache_range(void *vaddr, unsigned int size) +static void clflush_cache_range_opt(void *vaddr, unsigned int size) { const unsigned long clflush_size = boot_cpu_data.x86_clflush_size; void *p = (void *)((unsigned long)vaddr & ~(clflush_size - 1)); @@ -268,11 +260,22 @@ void clflush_cache_range(void *vaddr, unsigned int size) if (p >= vend) return; - mb(); - for (; p < vend; p += clflush_size) clflushopt(p); +} +/** + * clflush_cache_range - flush a cache range with clflush + * @vaddr: virtual start address + * @size: number of bytes to flush + * + * CLFLUSHOPT is an unordered instruction which needs fencing with MFENCE or + * SFENCE to avoid ordering issues. + */ +void clflush_cache_range(void *vaddr, unsigned int size) +{ + mb(); + clflush_cache_range_opt(vaddr, size); mb(); } EXPORT_SYMBOL_GPL(clflush_cache_range); @@ -333,6 +336,7 @@ static void cpa_flush(struct cpa_data *data, int cache) if (!cache) return; + mb(); for (i = 0; i < cpa->numpages; i++) { unsigned long addr = __cpa_addr(cpa, i); unsigned int level; @@ -343,8 +347,9 @@ static void cpa_flush(struct cpa_data *data, int cache) * Only flush present addresses: */ if (pte && (pte_val(*pte) & _PAGE_PRESENT)) - clflush_cache_range((void *)addr, PAGE_SIZE); + clflush_cache_range_opt((void *)addr, PAGE_SIZE); } + mb(); } static bool overlaps(unsigned long r1_start, unsigned long r1_end,
