Commit 6c434d61 authored May 11, 2015 by Ross Zwisler Committed by Ingo Molnar May 11, 2015

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>

parent 030bbdbf

arch/x86/mm/pageattr.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -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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