diff options
Diffstat (limited to 'arch/arm64/lib/copy_from_user.S')
-rw-r--r-- | arch/arm64/lib/copy_from_user.S | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S new file mode 100644 index 0000000000..34e3179075 --- /dev/null +++ b/arch/arm64/lib/copy_from_user.S @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2012 ARM Ltd. + */ + +#include <linux/linkage.h> + +#include <asm/asm-uaccess.h> +#include <asm/assembler.h> +#include <asm/cache.h> + +/* + * Copy from user space to a kernel buffer (alignment handled by the hardware) + * + * Parameters: + * x0 - to + * x1 - from + * x2 - n + * Returns: + * x0 - bytes not copied + */ + + .macro ldrb1 reg, ptr, val + user_ldst 9998f, ldtrb, \reg, \ptr, \val + .endm + + .macro strb1 reg, ptr, val + strb \reg, [\ptr], \val + .endm + + .macro ldrh1 reg, ptr, val + user_ldst 9997f, ldtrh, \reg, \ptr, \val + .endm + + .macro strh1 reg, ptr, val + strh \reg, [\ptr], \val + .endm + + .macro ldr1 reg, ptr, val + user_ldst 9997f, ldtr, \reg, \ptr, \val + .endm + + .macro str1 reg, ptr, val + str \reg, [\ptr], \val + .endm + + .macro ldp1 reg1, reg2, ptr, val + user_ldp 9997f, \reg1, \reg2, \ptr, \val + .endm + + .macro stp1 reg1, reg2, ptr, val + stp \reg1, \reg2, [\ptr], \val + .endm + +end .req x5 +srcin .req x15 +SYM_FUNC_START(__arch_copy_from_user) + add end, x0, x2 + mov srcin, x1 +#include "copy_template.S" + mov x0, #0 // Nothing to copy + ret + + // Exception fixups +9997: cmp dst, dstin + b.ne 9998f + // Before being absolutely sure we couldn't copy anything, try harder +USER(9998f, ldtrb tmp1w, [srcin]) + strb tmp1w, [dst], #1 +9998: sub x0, end, dst // bytes not copied + ret +SYM_FUNC_END(__arch_copy_from_user) +EXPORT_SYMBOL(__arch_copy_from_user) |