linux/arch/arm/lib/copy_to_user.S
Arnd Bergmann 8ac6f5d7f8 ARM: 9113/1: uaccess: remove set_fs() implementation
There are no remaining callers of set_fs(), so just remove it
along with all associated code that operates on
thread_info->addr_limit.

There are still further optimizations that can be done:

- In get_user(), the address check could be moved entirely
  into the out of line code, rather than passing a constant
  as an argument,

- I assume the DACR handling can be simplified as we now
  only change it during user access when CONFIG_CPU_SW_DOMAIN_PAN
  is set, but not during set_fs().

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-08-20 11:39:27 +01:00

129 lines
2.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/lib/copy_to_user.S
*
* Author: Nicolas Pitre
* Created: Sep 29, 2005
* Copyright: MontaVista Software, Inc.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>
/*
* Prototype:
*
* size_t arm_copy_to_user(void *to, const void *from, size_t n)
*
* Purpose:
*
* copy a block to user memory from kernel memory
*
* Params:
*
* to = user memory
* from = kernel memory
* n = number of bytes to copy
*
* Return value:
*
* Number of bytes NOT copied.
*/
#define LDR1W_SHIFT 0
.macro ldr1w ptr reg abort
W(ldr) \reg, [\ptr], #4
.endm
.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4}
.endm
.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
.endm
.macro ldr1b ptr reg cond=al abort
ldrb\cond \reg, [\ptr], #1
.endm
#ifdef CONFIG_CPU_USE_DOMAINS
#ifndef CONFIG_THUMB2_KERNEL
#define STR1W_SHIFT 0
#else
#define STR1W_SHIFT 1
#endif
.macro str1w ptr reg abort
strusr \reg, \ptr, 4, abort=\abort
.endm
.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
str1w \ptr, \reg1, \abort
str1w \ptr, \reg2, \abort
str1w \ptr, \reg3, \abort
str1w \ptr, \reg4, \abort
str1w \ptr, \reg5, \abort
str1w \ptr, \reg6, \abort
str1w \ptr, \reg7, \abort
str1w \ptr, \reg8, \abort
.endm
#else
#define STR1W_SHIFT 0
.macro str1w ptr reg abort
USERL(\abort, W(str) \reg, [\ptr], #4)
.endm
.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
USERL(\abort, stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8})
.endm
#endif /* CONFIG_CPU_USE_DOMAINS */
.macro str1b ptr reg cond=al abort
strusr \reg, \ptr, 1, \cond, abort=\abort
.endm
.macro enter reg1 reg2
mov r3, #0
stmdb sp!, {r0, r2, r3, \reg1, \reg2}
.endm
.macro usave reg1 reg2
UNWIND( .save {r0, r2, r3, \reg1, \reg2} )
.endm
.macro exit reg1 reg2
add sp, sp, #8
ldmfd sp!, {r0, \reg1, \reg2}
.endm
.text
ENTRY(__copy_to_user_std)
WEAK(arm_copy_to_user)
#ifdef CONFIG_CPU_SPECTRE
ldr r3, =TASK_SIZE
uaccess_mask_range_ptr r0, r2, r3, ip
#endif
#include "copy_template.S"
ENDPROC(arm_copy_to_user)
ENDPROC(__copy_to_user_std)
.pushsection .text.fixup,"ax"
.align 0
copy_abort_preamble
ldmfd sp!, {r1, r2, r3}
sub r0, r0, r1
rsb r0, r0, r2
copy_abort_end
.popsection