1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * kexec trampoline 4 * 5 * Based on code taken from kexec-tools and kexec-lite. 6 * 7 * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation 8 * Copyright (C) 2006, Mohan Kumar M, IBM Corporation 9 * Copyright (C) 2013, Anton Blanchard, IBM Corporation 10 */ 11 12#include <asm/asm-compat.h> 13#include <asm/crashdump-ppc64.h> 14 15 .machine ppc64 16 .balign 256 17 .globl purgatory_start 18purgatory_start: 19 b master 20 21 /* ABI: possible run_at_load flag at 0x5c */ 22 .org purgatory_start + 0x5c 23 .globl run_at_load 24run_at_load: 25 .long 0 26 .size run_at_load, . - run_at_load 27 28 /* ABI: slaves start at 60 with r3=phys */ 29 .org purgatory_start + 0x60 30slave: 31 b . 32 /* ABI: end of copied region */ 33 .org purgatory_start + 0x100 34 .size purgatory_start, . - purgatory_start 35 36/* 37 * The above 0x100 bytes at purgatory_start are replaced with the 38 * code from the kernel (or next stage) by setup_purgatory(). 39 */ 40 41master: 42 or %r1,%r1,%r1 /* low priority to let other threads catchup */ 43 isync 44 mr %r17,%r3 /* save cpu id to r17 */ 45 mr %r15,%r4 /* save physical address in reg15 */ 46 47 /* Work out where we're running */ 48 bcl 20, 31, 0f 490: mflr %r18 50 51 /* 52 * Copy BACKUP_SRC_SIZE bytes from BACKUP_SRC_START to 53 * backup_start 8 bytes at a time. 54 * 55 * Use r3 = dest, r4 = src, r5 = size, r6 = count 56 */ 57 ld %r3, (backup_start - 0b)(%r18) 58 cmpdi %cr0, %r3, 0 59 beq .Lskip_copy /* skip if there is no backup region */ 60 lis %r5, BACKUP_SRC_SIZE@h 61 ori %r5, %r5, BACKUP_SRC_SIZE@l 62 cmpdi %cr0, %r5, 0 63 beq .Lskip_copy /* skip if copy size is zero */ 64 lis %r4, BACKUP_SRC_START@h 65 ori %r4, %r4, BACKUP_SRC_START@l 66 li %r6, 0 67.Lcopy_loop: 68 ldx %r0, %r6, %r4 69 stdx %r0, %r6, %r3 70 addi %r6, %r6, 8 71 cmpld %cr0, %r6, %r5 72 blt .Lcopy_loop 73 74.Lskip_copy: 75 or %r3,%r3,%r3 /* ok now to high priority, lets boot */ 76 lis %r6,0x1 77 mtctr %r6 /* delay a bit for slaves to catch up */ 78 bdnz . /* before we overwrite 0-100 again */ 79 80 /* load device-tree address */ 81 ld %r3, (dt_offset - 0b)(%r18) 82 mr %r16,%r3 /* save dt address in reg16 */ 83 li %r4,20 84 LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */ 85 cmpwi %cr0,%r6,2 /* v2 or later? */ 86 blt 1f 87 li %r4,28 88 STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */ 891: 90 /* load the kernel address */ 91 ld %r4,(kernel - 0b)(%r18) 92 93 /* load the run_at_load flag */ 94 /* possibly patched by kexec */ 95 ld %r6,(run_at_load - 0b)(%r18) 96 /* and patch it into the kernel */ 97 stw %r6,(0x5c)(%r4) 98 99 mr %r3,%r16 /* restore dt address */ 100 101 li %r5,0 /* r5 will be 0 for kernel */ 102 103 mfmsr %r11 104 andi. %r10,%r11,1 /* test MSR_LE */ 105 bne .Little_endian 106 107 mtctr %r4 /* prepare branch to */ 108 bctr /* start kernel */ 109 110.Little_endian: 111 mtsrr0 %r4 /* prepare branch to */ 112 113 clrrdi %r11,%r11,1 /* clear MSR_LE */ 114 mtsrr1 %r11 115 116 rfid /* update MSR and start kernel */ 117 118 .balign 8 119 .globl kernel 120kernel: 121 .8byte 0x0 122 .size kernel, . - kernel 123 124 .balign 8 125 .globl dt_offset 126dt_offset: 127 .8byte 0x0 128 .size dt_offset, . - dt_offset 129 130 .balign 8 131 .globl backup_start 132backup_start: 133 .8byte 0x0 134 .size backup_start, . - backup_start 135 136 .data 137 .balign 8 138.globl purgatory_sha256_digest 139purgatory_sha256_digest: 140 .skip 32 141 .size purgatory_sha256_digest, . - purgatory_sha256_digest 142 143 .balign 8 144.globl purgatory_sha_regions 145purgatory_sha_regions: 146 .skip 8 * 2 * 16 147 .size purgatory_sha_regions, . - purgatory_sha_regions 148