mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 05:48:40 +00:00
af1b3cf2c2
When kuser helpers are enabled the kernel maps the relative code at a fixed address (0xffff0000). Making configurable the option to disable them means that the kernel can remove this mapping and any access to this memory area results in a sigfault. Add a KUSER_HELPERS config option that can be used to disable the mapping when it is turned off. This option can be turned off if and only if the applications are designed specifically for the platform and they do not make use of the kuser helpers code. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> [will: Use IS_ENABLED() instead of #ifdef] Signed-off-by: Will Deacon <will.deacon@arm.com>
64 lines
1.8 KiB
ArmAsm
64 lines
1.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* AArch32 user helpers.
|
|
* Based on the kuser helpers in arch/arm/kernel/entry-armv.S.
|
|
*
|
|
* Copyright (C) 2005-2011 Nicolas Pitre <nico@fluxnic.net>
|
|
* Copyright (C) 2012-2018 ARM Ltd.
|
|
*
|
|
* The kuser helpers below are mapped at a fixed address by
|
|
* aarch32_setup_additional_pages() and are provided for compatibility
|
|
* reasons with 32 bit (aarch32) applications that need them.
|
|
*
|
|
* See Documentation/arm/kernel_user_helpers.txt for formal definitions.
|
|
*/
|
|
|
|
#include <asm/unistd.h>
|
|
|
|
.align 5
|
|
.globl __kuser_helper_start
|
|
__kuser_helper_start:
|
|
|
|
__kuser_cmpxchg64: // 0xffff0f60
|
|
.inst 0xe92d00f0 // push {r4, r5, r6, r7}
|
|
.inst 0xe1c040d0 // ldrd r4, r5, [r0]
|
|
.inst 0xe1c160d0 // ldrd r6, r7, [r1]
|
|
.inst 0xe1b20f9f // 1: ldrexd r0, r1, [r2]
|
|
.inst 0xe0303004 // eors r3, r0, r4
|
|
.inst 0x00313005 // eoreqs r3, r1, r5
|
|
.inst 0x01a23e96 // stlexdeq r3, r6, [r2]
|
|
.inst 0x03330001 // teqeq r3, #1
|
|
.inst 0x0afffff9 // beq 1b
|
|
.inst 0xf57ff05b // dmb ish
|
|
.inst 0xe2730000 // rsbs r0, r3, #0
|
|
.inst 0xe8bd00f0 // pop {r4, r5, r6, r7}
|
|
.inst 0xe12fff1e // bx lr
|
|
|
|
.align 5
|
|
__kuser_memory_barrier: // 0xffff0fa0
|
|
.inst 0xf57ff05b // dmb ish
|
|
.inst 0xe12fff1e // bx lr
|
|
|
|
.align 5
|
|
__kuser_cmpxchg: // 0xffff0fc0
|
|
.inst 0xe1923f9f // 1: ldrex r3, [r2]
|
|
.inst 0xe0533000 // subs r3, r3, r0
|
|
.inst 0x01823e91 // stlexeq r3, r1, [r2]
|
|
.inst 0x03330001 // teqeq r3, #1
|
|
.inst 0x0afffffa // beq 1b
|
|
.inst 0xf57ff05b // dmb ish
|
|
.inst 0xe2730000 // rsbs r0, r3, #0
|
|
.inst 0xe12fff1e // bx lr
|
|
|
|
.align 5
|
|
__kuser_get_tls: // 0xffff0fe0
|
|
.inst 0xee1d0f70 // mrc p15, 0, r0, c13, c0, 3
|
|
.inst 0xe12fff1e // bx lr
|
|
.rep 5
|
|
.word 0
|
|
.endr
|
|
|
|
__kuser_helper_version: // 0xffff0ffc
|
|
.word ((__kuser_helper_end - __kuser_helper_start) >> 5)
|
|
.globl __kuser_helper_end
|
|
__kuser_helper_end:
|