From 0aea86a2176c22647a5b683768f858d880d5e05b Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 5 Mar 2012 11:49:32 +0000 Subject: 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 Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas Acked-by: Tony Lindgren Acked-by: Nicolas Pitre Acked-by: Olof Johansson Acked-by: Santosh Shilimkar Acked-by: Arnd Bergmann --- arch/arm64/lib/copy_to_user.S | 61 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 arch/arm64/lib/copy_to_user.S (limited to 'arch/arm64/lib/copy_to_user.S') diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S new file mode 100644 index 000000000000..a0aeeb9b7a28 --- /dev/null +++ b/arch/arm64/lib/copy_to_user.S @@ -0,0 +1,61 @@ +/* + * 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 . + */ + +#include +#include + +/* + * Copy to user space from a kernel buffer (alignment handled by the hardware) + * + * Parameters: + * x0 - to + * x1 - from + * x2 - n + * Returns: + * x0 - bytes not copied + */ +ENTRY(__copy_to_user) + add x4, x0, x2 // upper user buffer boundary + subs x2, x2, #8 + b.mi 2f +1: + 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 + ldr w3, [x1], #4 + sub x2, x2, #4 +USER(9f, str w3, [x0], #4 ) +3: adds x2, x2, #2 + b.mi 4f + ldrh w3, [x1], #2 + sub x2, x2, #2 +USER(9f, strh w3, [x0], #2 ) +4: adds x2, x2, #1 + b.mi 5f + ldrb w3, [x1] +USER(9f, strb w3, [x0] ) +5: mov x0, #0 + ret +ENDPROC(__copy_to_user) + + .section .fixup,"ax" + .align 2 +9: sub x0, x4, x0 // bytes not copied + ret + .previous -- cgit v1.2.3