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author | Catalin Marinas <catalin.marinas@arm.com> | 2012-03-05 11:49:32 (GMT) |
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committer | Catalin Marinas <catalin.marinas@arm.com> | 2012-09-17 12:42:11 (GMT) |
commit | 0aea86a2176c22647a5b683768f858d880d5e05b (patch) | |
tree | 6ffad0914ef41e69c672a0862f5a10a9e9f3cb43 /arch/arm64/lib/copy_in_user.S | |
parent | 2c020ed8d148f7562c01abaf875c9bbfb9a40a83 (diff) | |
download | linux-0aea86a2176c22647a5b683768f858d880d5e05b.tar.xz |
arm64: User access library functions
This patch add support for various user access functions. These
functions use the standard LDR/STR instructions and not the LDRT/STRT
variants in order to allow kernel addresses (after set_fs(KERNEL_DS)).
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arm64/lib/copy_in_user.S')
-rw-r--r-- | arch/arm64/lib/copy_in_user.S | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S new file mode 100644 index 0000000..84b6c9b --- /dev/null +++ b/arch/arm64/lib/copy_in_user.S @@ -0,0 +1,63 @@ +/* + * Copy from user space to user space + * + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/linkage.h> +#include <asm/assembler.h> + +/* + * Copy from user space to user space (alignment handled by the hardware) + * + * Parameters: + * x0 - to + * x1 - from + * x2 - n + * Returns: + * x0 - bytes not copied + */ +ENTRY(__copy_in_user) + add x4, x0, x2 // upper user buffer boundary + subs x2, x2, #8 + b.mi 2f +1: +USER(9f, ldr x3, [x1], #8 ) + subs x2, x2, #8 +USER(9f, str x3, [x0], #8 ) + b.pl 1b +2: adds x2, x2, #4 + b.mi 3f +USER(9f, ldr w3, [x1], #4 ) + sub x2, x2, #4 +USER(9f, str w3, [x0], #4 ) +3: adds x2, x2, #2 + b.mi 4f +USER(9f, ldrh w3, [x1], #2 ) + sub x2, x2, #2 +USER(9f, strh w3, [x0], #2 ) +4: adds x2, x2, #1 + b.mi 5f +USER(9f, ldrb w3, [x1] ) +USER(9f, strb w3, [x0] ) +5: mov x0, #0 + ret +ENDPROC(__copy_in_user) + + .section .fixup,"ax" + .align 2 +9: sub x0, x4, x0 // bytes not copied + ret + .previous |