1/* 2 * Low-level user helpers placed in the vectors page for AArch32. 3 * Based on the kuser helpers in arch/arm/kernel/entry-armv.S. 4 * 5 * Copyright (C) 2005-2011 Nicolas Pitre <nico@fluxnic.net> 6 * Copyright (C) 2012 ARM Ltd. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 * 20 * 21 * AArch32 user helpers. 22 * 23 * Each segment is 32-byte aligned and will be moved to the top of the high 24 * vector page. New segments (if ever needed) must be added in front of 25 * existing ones. This mechanism should be used only for things that are 26 * really small and justified, and not be abused freely. 27 * 28 * See Documentation/arm/kernel_user_helpers.txt for formal definitions. 29 */ 30 .align 5 31 .globl __kuser_helper_start 32__kuser_helper_start: 33 34__kuser_cmpxchg64: // 0xffff0f60 35 .inst 0xe92d00f0 // push {r4, r5, r6, r7} 36 .inst 0xe1c040d0 // ldrd r4, r5, [r0] 37 .inst 0xe1c160d0 // ldrd r6, r7, [r1] 38 .inst 0xf57ff05f // dmb sy 39 .inst 0xe1b20f9f // 1: ldrexd r0, r1, [r2] 40 .inst 0xe0303004 // eors r3, r0, r4 41 .inst 0x00313005 // eoreqs r3, r1, r5 42 .inst 0x01a23f96 // strexdeq r3, r6, [r2] 43 .inst 0x03330001 // teqeq r3, #1 44 .inst 0x0afffff9 // beq 1b 45 .inst 0xf57ff05f // dmb sy 46 .inst 0xe2730000 // rsbs r0, r3, #0 47 .inst 0xe8bd00f0 // pop {r4, r5, r6, r7} 48 .inst 0xe12fff1e // bx lr 49 50 .align 5 51__kuser_memory_barrier: // 0xffff0fa0 52 .inst 0xf57ff05f // dmb sy 53 .inst 0xe12fff1e // bx lr 54 55 .align 5 56__kuser_cmpxchg: // 0xffff0fc0 57 .inst 0xf57ff05f // dmb sy 58 .inst 0xe1923f9f // 1: ldrex r3, [r2] 59 .inst 0xe0533000 // subs r3, r3, r0 60 .inst 0x01823f91 // strexeq r3, r1, [r2] 61 .inst 0x03330001 // teqeq r3, #1 62 .inst 0x0afffffa // beq 1b 63 .inst 0xe2730000 // rsbs r0, r3, #0 64 .inst 0xeaffffef // b <__kuser_memory_barrier> 65 66 .align 5 67__kuser_get_tls: // 0xffff0fe0 68 .inst 0xee1d0f70 // mrc p15, 0, r0, c13, c0, 3 69 .inst 0xe12fff1e // bx lr 70 .rep 5 71 .word 0 72 .endr 73 74__kuser_helper_version: // 0xffff0ffc 75 .word ((__kuser_helper_end - __kuser_helper_start) >> 5) 76 .globl __kuser_helper_end 77__kuser_helper_end: 78