1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Hibernate low-level support 4 * 5 * Copyright (C) 2016 ARM Ltd. 6 * Author: James Morse <james.morse@arm.com> 7 */ 8#include <linux/linkage.h> 9#include <linux/errno.h> 10 11#include <asm/asm-offsets.h> 12#include <asm/assembler.h> 13#include <asm/cputype.h> 14#include <asm/memory.h> 15#include <asm/page.h> 16#include <asm/virt.h> 17 18/* 19 * To prevent the possibility of old and new partial table walks being visible 20 * in the tlb, switch the ttbr to a zero page when we invalidate the old 21 * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i 22 * Even switching to our copied tables will cause a changed output address at 23 * each stage of the walk. 24 */ 25.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2 26 phys_to_ttbr \tmp, \zero_page 27 msr ttbr1_el1, \tmp 28 isb 29 tlbi vmalle1 30 dsb nsh 31 phys_to_ttbr \tmp, \page_table 32 offset_ttbr1 \tmp, \tmp2 33 msr ttbr1_el1, \tmp 34 isb 35.endm 36 37 38/* 39 * Resume from hibernate 40 * 41 * Loads temporary page tables then restores the memory image. 42 * Finally branches to cpu_resume() to restore the state saved by 43 * swsusp_arch_suspend(). 44 * 45 * Because this code has to be copied to a 'safe' page, it can't call out to 46 * other functions by PC-relative address. Also remember that it may be 47 * mid-way through over-writing other functions. For this reason it contains 48 * code from flush_icache_range() and uses the copy_page() macro. 49 * 50 * This 'safe' page is mapped via ttbr0, and executed from there. This function 51 * switches to a copy of the linear map in ttbr1, performs the restore, then 52 * switches ttbr1 to the original kernel's swapper_pg_dir. 53 * 54 * All of memory gets written to, including code. We need to clean the kernel 55 * text to the Point of Coherence (PoC) before secondary cores can be booted. 56 * Because the kernel modules and executable pages mapped to user space are 57 * also written as data, we clean all pages we touch to the Point of 58 * Unification (PoU). 59 * 60 * x0: physical address of temporary page tables 61 * x1: physical address of swapper page tables 62 * x2: address of cpu_resume 63 * x3: linear map address of restore_pblist in the current kernel 64 * x4: physical address of __hyp_stub_vectors, or 0 65 * x5: physical address of a zero page that remains zero after resume 66 */ 67.pushsection ".hibernate_exit.text", "ax" 68ENTRY(swsusp_arch_suspend_exit) 69 /* 70 * We execute from ttbr0, change ttbr1 to our copied linear map tables 71 * with a break-before-make via the zero page 72 */ 73 break_before_make_ttbr_switch x5, x0, x6, x8 74 75 mov x21, x1 76 mov x30, x2 77 mov x24, x4 78 mov x25, x5 79 80 /* walk the restore_pblist and use copy_page() to over-write memory */ 81 mov x19, x3 82 831: ldr x10, [x19, #HIBERN_PBE_ORIG] 84 mov x0, x10 85 ldr x1, [x19, #HIBERN_PBE_ADDR] 86 87 copy_page x0, x1, x2, x3, x4, x5, x6, x7, x8, x9 88 89 add x1, x10, #PAGE_SIZE 90 /* Clean the copied page to PoU - based on flush_icache_range() */ 91 raw_dcache_line_size x2, x3 92 sub x3, x2, #1 93 bic x4, x10, x3 942: dc cvau, x4 /* clean D line / unified line */ 95 add x4, x4, x2 96 cmp x4, x1 97 b.lo 2b 98 99 ldr x19, [x19, #HIBERN_PBE_NEXT] 100 cbnz x19, 1b 101 dsb ish /* wait for PoU cleaning to finish */ 102 103 /* switch to the restored kernels page tables */ 104 break_before_make_ttbr_switch x25, x21, x6, x8 105 106 ic ialluis 107 dsb ish 108 isb 109 110 cbz x24, 3f /* Do we need to re-initialise EL2? */ 111 hvc #0 1123: ret 113ENDPROC(swsusp_arch_suspend_exit) 114 115/* 116 * Restore the hyp stub. 117 * This must be done before the hibernate page is unmapped by _cpu_resume(), 118 * but happens before any of the hyp-stub's code is cleaned to PoC. 119 * 120 * x24: The physical address of __hyp_stub_vectors 121 */ 122el1_sync: 123 msr vbar_el2, x24 124 eret 125ENDPROC(el1_sync) 126 127.macro invalid_vector label 128\label: 129 b \label 130ENDPROC(\label) 131.endm 132 133 invalid_vector el2_sync_invalid 134 invalid_vector el2_irq_invalid 135 invalid_vector el2_fiq_invalid 136 invalid_vector el2_error_invalid 137 invalid_vector el1_sync_invalid 138 invalid_vector el1_irq_invalid 139 invalid_vector el1_fiq_invalid 140 invalid_vector el1_error_invalid 141 142/* el2 vectors - switch el2 here while we restore the memory image. */ 143 .align 11 144ENTRY(hibernate_el2_vectors) 145 ventry el2_sync_invalid // Synchronous EL2t 146 ventry el2_irq_invalid // IRQ EL2t 147 ventry el2_fiq_invalid // FIQ EL2t 148 ventry el2_error_invalid // Error EL2t 149 150 ventry el2_sync_invalid // Synchronous EL2h 151 ventry el2_irq_invalid // IRQ EL2h 152 ventry el2_fiq_invalid // FIQ EL2h 153 ventry el2_error_invalid // Error EL2h 154 155 ventry el1_sync // Synchronous 64-bit EL1 156 ventry el1_irq_invalid // IRQ 64-bit EL1 157 ventry el1_fiq_invalid // FIQ 64-bit EL1 158 ventry el1_error_invalid // Error 64-bit EL1 159 160 ventry el1_sync_invalid // Synchronous 32-bit EL1 161 ventry el1_irq_invalid // IRQ 32-bit EL1 162 ventry el1_fiq_invalid // FIQ 32-bit EL1 163 ventry el1_error_invalid // Error 32-bit EL1 164END(hibernate_el2_vectors) 165 166.popsection 167