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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copy_user.S (780B)

      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, a2, \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 __copy_user(void *to, const void *from, size_t n)
     25 *
     26 * a0: to
     27 * a1: from
     28 * a2: n
     29 */
     30SYM_FUNC_START(__copy_user)
     31	beqz	a2, 3f
     32
     331:	ld.b	t0, a1, 0
     342:	st.b	t0, a0, 0
     35	addi.d	a0, a0, 1
     36	addi.d	a1, a1, 1
     37	addi.d	a2, a2, -1
     38	bgt	a2, zero, 1b
     39
     403:	move	a0, a2
     41	jr	ra
     42
     43	fixup_ex 1, 4, 0, 1
     44	fixup_ex 2, 4, 0, 0
     45SYM_FUNC_END(__copy_user)
     46
     47EXPORT_SYMBOL(__copy_user)