1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * kexec for arm64 4 * 5 * Copyright (C) Linaro. 6 * Copyright (C) Huawei Futurewei Technologies. 7 */ 8 9#include <linux/kexec.h> 10#include <linux/linkage.h> 11 12#include <asm/assembler.h> 13#include <asm/kexec.h> 14#include <asm/page.h> 15#include <asm/sysreg.h> 16 17/* 18 * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it. 19 * 20 * The memory that the old kernel occupies may be overwritten when coping the 21 * new image to its final location. To assure that the 22 * arm64_relocate_new_kernel routine which does that copy is not overwritten, 23 * all code and data needed by arm64_relocate_new_kernel must be between the 24 * symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end. The 25 * machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec 26 * control_code_page, a special page which has been set up to be preserved 27 * during the copy operation. 28 */ 29ENTRY(arm64_relocate_new_kernel) 30 31 /* Setup the list loop variables. */ 32 mov x18, x2 /* x18 = dtb address */ 33 mov x17, x1 /* x17 = kimage_start */ 34 mov x16, x0 /* x16 = kimage_head */ 35 raw_dcache_line_size x15, x0 /* x15 = dcache line size */ 36 mov x14, xzr /* x14 = entry ptr */ 37 mov x13, xzr /* x13 = copy dest */ 38 39 /* Clear the sctlr_el2 flags. */ 40 mrs x0, CurrentEL 41 cmp x0, #CurrentEL_EL2 42 b.ne 1f 43 mrs x0, sctlr_el2 44 ldr x1, =SCTLR_ELx_FLAGS 45 bic x0, x0, x1 46 pre_disable_mmu_workaround 47 msr sctlr_el2, x0 48 isb 491: 50 51 /* Check if the new image needs relocation. */ 52 tbnz x16, IND_DONE_BIT, .Ldone 53 54.Lloop: 55 and x12, x16, PAGE_MASK /* x12 = addr */ 56 57 /* Test the entry flags. */ 58.Ltest_source: 59 tbz x16, IND_SOURCE_BIT, .Ltest_indirection 60 61 /* Invalidate dest page to PoC. */ 62 mov x0, x13 63 add x20, x0, #PAGE_SIZE 64 sub x1, x15, #1 65 bic x0, x0, x1 662: dc ivac, x0 67 add x0, x0, x15 68 cmp x0, x20 69 b.lo 2b 70 dsb sy 71 72 mov x20, x13 73 mov x21, x12 74 copy_page x20, x21, x0, x1, x2, x3, x4, x5, x6, x7 75 76 /* dest += PAGE_SIZE */ 77 add x13, x13, PAGE_SIZE 78 b .Lnext 79 80.Ltest_indirection: 81 tbz x16, IND_INDIRECTION_BIT, .Ltest_destination 82 83 /* ptr = addr */ 84 mov x14, x12 85 b .Lnext 86 87.Ltest_destination: 88 tbz x16, IND_DESTINATION_BIT, .Lnext 89 90 /* dest = addr */ 91 mov x13, x12 92 93.Lnext: 94 /* entry = *ptr++ */ 95 ldr x16, [x14], #8 96 97 /* while (!(entry & DONE)) */ 98 tbz x16, IND_DONE_BIT, .Lloop 99 100.Ldone: 101 /* wait for writes from copy_page to finish */ 102 dsb nsh 103 ic iallu 104 dsb nsh 105 isb 106 107 /* Start new image. */ 108 mov x0, x18 109 mov x1, xzr 110 mov x2, xzr 111 mov x3, xzr 112 br x17 113 114ENDPROC(arm64_relocate_new_kernel) 115 116.ltorg 117 118.align 3 /* To keep the 64-bit values below naturally aligned. */ 119 120.Lcopy_end: 121.org KEXEC_CONTROL_PAGE_SIZE 122 123/* 124 * arm64_relocate_new_kernel_size - Number of bytes to copy to the 125 * control_code_page. 126 */ 127.globl arm64_relocate_new_kernel_size 128arm64_relocate_new_kernel_size: 129 .quad .Lcopy_end - arm64_relocate_new_kernel 130