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_user.S (709B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
      4 */
      5
      6#include <asm/asm.h>
      7#include <asm/asmmacro.h>
      8#include <asm/export.h>
      9#include <asm/regdef.h>
     10
     11.macro fixup_ex from, to, offset, fix
     12.if \fix
     13	.section .fixup, "ax"
     14\to:	addi.d	a0, a1, \offset
     15	jr	ra
     16	.previous
     17.endif
     18	.section __ex_table, "a"
     19	PTR	\from\()b, \to\()b
     20	.previous
     21.endm
     22
     23/*
     24 * unsigned long __clear_user(void *addr, size_t size)
     25 *
     26 * a0: addr
     27 * a1: size
     28 */
     29SYM_FUNC_START(__clear_user)
     30	beqz	a1, 2f
     31
     321:	st.b	zero, a0, 0
     33	addi.d	a0, a0, 1
     34	addi.d	a1, a1, -1
     35	bgt	a1, zero, 1b
     36
     372:	move	a0, a1
     38	jr	ra
     39
     40	fixup_ex 1, 3, 0, 1
     41SYM_FUNC_END(__clear_user)
     42
     43EXPORT_SYMBOL(__clear_user)