[PATCH v2 4/6] x86: Add clear_page_nocache

[Kirill A. Shutemov]

On Mon, Aug 13, 2012 at 07:04:02PM +0200, Borislav Petkov wrote:
> On Mon, Aug 13, 2012 at 02:43:34PM +0300, Kirill A. Shutemov wrote:
> > $ cat test.c
> > #include <stdio.h>
> > #include <sys/mman.h>
> > 
> > #define SIZE 1024*1024*1024
> > 
> > void clear_page_nocache_sse2(void *page) __attribute__((regparm(1)));
> > 
> > int main(int argc, char** argv)
> > {
> >         char *p;
> >         unsigned long i, j;
> > 
> >         p = mmap(NULL, SIZE, PROT_WRITE|PROT_READ,
> >                         MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
> >         for(j = 0; j < 100; j++) {
> >                 for(i = 0; i < SIZE; i += 4096) {
> >                         clear_page_nocache_sse2(p + i);
> >                 }
> >         }
> > 
> >         return 0;
> > }
> > $ cat clear_page_nocache_unroll32.S
> > .globl clear_page_nocache_sse2
> > .align 4,0x90
> > clear_page_nocache_sse2:
> > .cfi_startproc
> >         mov    %eax,%edx
> >         xorl   %eax,%eax
> >         movl   $4096/32,%ecx
> >         .p2align 4
> > .Lloop_sse2:
> >         decl    %ecx
> > #define PUT(x) movnti %eax,x*4(%edx)
> >         PUT(0)
> >         PUT(1)
> >         PUT(2)
> >         PUT(3)
> >         PUT(4)
> >         PUT(5)
> >         PUT(6)
> >         PUT(7)
> > #undef PUT
> >         lea     32(%edx),%edx
> >         jnz     .Lloop_sse2
> >         nop
> >         ret
> > .cfi_endproc
> > .type clear_page_nocache_sse2, @function
> > .size clear_page_nocache_sse2, .-clear_page_nocache_sse2
> > $ cat clear_page_nocache_unroll64.S
> > .globl clear_page_nocache_sse2
> > .align 4,0x90
> > clear_page_nocache_sse2:
> > .cfi_startproc
> >         mov    %eax,%edx
> 
> This must still be the 32-bit version becaue it segfaults here.

Yes, it's test for 32-bit version.

-- 
 Kirill A. Shutemov