| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 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 | */ |
| 29 | ENTRY(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 |
| 49 | 1: |
| 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 |
| 66 | 2: 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 | |
| 114 | ENDPROC(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 |
| 128 | arm64_relocate_new_kernel_size: |
| 129 | .quad .Lcopy_end - arm64_relocate_new_kernel |