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, and remove arithmetic on void pointers. Void pointer arithmetic is allowed by GCC extensions, but isn't part of the base C standards. Signed-off-by: Ross Zwisler <ross.zwis...@linux.intel.com> Reported-by: H. Peter Anvin <h...@zytor.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: x...@kernel.org Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Borislav Petkov <b...@suse.de> --- 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 ae242a7c11c7..b75ecac859f2 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -131,16 +131,15 @@ 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; + char *vend = (char *)vaddr + size; + char *p; mb(); - for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size) - clflushopt(vaddr); - /* - * Flush any possible final partial cacheline: - */ - clflushopt(vend); + for (p = (char *)((unsigned long)vaddr & ~clflush_mask); + p < vend; p += boot_cpu_data.x86_clflush_size) + clflushopt(p); mb(); } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/