cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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clear_page_64.S (993B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2#include <linux/linkage.h>
      3#include <asm/export.h>
      4
      5/*
      6 * Most CPUs support enhanced REP MOVSB/STOSB instructions. It is
      7 * recommended to use this when possible and we do use them by default.
      8 * If enhanced REP MOVSB/STOSB is not available, try to use fast string.
      9 * Otherwise, use original.
     10 */
     11
     12/*
     13 * Zero a page.
     14 * %rdi	- page
     15 */
     16SYM_FUNC_START(clear_page_rep)
     17	movl $4096/8,%ecx
     18	xorl %eax,%eax
     19	rep stosq
     20	RET
     21SYM_FUNC_END(clear_page_rep)
     22EXPORT_SYMBOL_GPL(clear_page_rep)
     23
     24SYM_FUNC_START(clear_page_orig)
     25	xorl   %eax,%eax
     26	movl   $4096/64,%ecx
     27	.p2align 4
     28.Lloop:
     29	decl	%ecx
     30#define PUT(x) movq %rax,x*8(%rdi)
     31	movq %rax,(%rdi)
     32	PUT(1)
     33	PUT(2)
     34	PUT(3)
     35	PUT(4)
     36	PUT(5)
     37	PUT(6)
     38	PUT(7)
     39	leaq	64(%rdi),%rdi
     40	jnz	.Lloop
     41	nop
     42	RET
     43SYM_FUNC_END(clear_page_orig)
     44EXPORT_SYMBOL_GPL(clear_page_orig)
     45
     46SYM_FUNC_START(clear_page_erms)
     47	movl $4096,%ecx
     48	xorl %eax,%eax
     49	rep stosb
     50	RET
     51SYM_FUNC_END(clear_page_erms)
     52EXPORT_SYMBOL_GPL(clear_page_erms)