Messages in this thread Patch in this message | | | Date | Mon, 11 May 2015 05:45:39 -0700 | From | tip-bot for Ross Zwisler <> | Subject | [tip:x86/mm] x86/mm: Do not flush last cacheline twice in clflush_cache_range() |
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Commit-ID: 6c434d6176c0cb42847c33245189667d645db7bf Gitweb: http://git.kernel.org/tip/6c434d6176c0cb42847c33245189667d645db7bf Author: Ross Zwisler <ross.zwisler@linux.intel.com> AuthorDate: Mon, 11 May 2015 10:15:49 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 11 May 2015 10:38:44 +0200
x86/mm: Do not flush last cacheline twice in clflush_cache_range()
The current algorithm used in clflush_cache_range() can cause the last cache line of the buffer to be flushed twice. Fix that algorithm so that each cache line will only be flushed once.
Reported-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Link: http://lkml.kernel.org/r/1430259192-18802-1-git-send-email-ross.zwisler@linux.intel.com Link: http://lkml.kernel.org/r/1431332153-18566-5-git-send-email-bp@alien8.de [ Changed it to 'void *' to simplify the type conversions. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/mm/pageattr.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 89af288..5ddd900 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -129,16 +129,15 @@ within(unsigned long addr, unsigned long start, unsigned long end) */ void clflush_cache_range(void *vaddr, unsigned int size) { - void *vend = vaddr + size - 1; + unsigned long clflush_mask = boot_cpu_data.x86_clflush_size - 1; + void *vend = vaddr + size; + void *p; mb(); - for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size) - clflushopt(vaddr); - /* - * Flush any possible final partial cacheline: - */ - clflushopt(vend); + for (p = (void *)((unsigned long)vaddr & ~clflush_mask); + p < vend; p += boot_cpu_data.x86_clflush_size) + clflushopt(p); mb(); }
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