| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| 2 | /* |
| 3 | * purgatory: setup code |
| 4 | * |
| 5 | * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) |
| 6 | * Copyright (C) 2014 Red Hat Inc. |
| 7 | * |
| 8 | * This code has been taken from kexec-tools. |
| 9 | */ |
| 10 | #include <asm/purgatory.h> |
| 11 | |
| 12 | .text |
| 13 | .globl purgatory_start |
| 14 | .balign 16 |
| 15 | purgatory_start: |
| 16 | .code64 |
| 17 | |
| 18 | /* Load a gdt so I know what the segment registers are */ |
| 19 | lgdt gdt(%rip) |
| 20 | |
| 21 | /* load the data segments */ |
| 22 | movl $0x18, %eax /* data segment */ |
| 23 | movl %eax, %ds |
| 24 | movl %eax, %es |
| 25 | movl %eax, %ss |
| 26 | movl %eax, %fs |
| 27 | movl %eax, %gs |
| 28 | |
| 29 | /* Setup a stack */ |
| 30 | leaq lstack_end(%rip), %rsp |
| 31 | |
| 32 | /* Call the C code */ |
| 33 | call purgatory |
| 34 | jmp entry64 |
| 35 | |
| 36 | .section ".rodata" |
| 37 | .balign 16 |
| 38 | gdt: /* 0x00 unusable segment |
| 39 | * 0x08 unused |
| 40 | * so use them as the gdt ptr |
| 41 | */ |
| 42 | .word gdt_end - gdt - 1 |
| 43 | .quad gdt |
| 44 | .word 0, 0, 0 |
| 45 | |
| 46 | /* 0x10 4GB flat code segment */ |
| 47 | .word 0xFFFF, 0x0000, 0x9A00, 0x00AF |
| 48 | |
| 49 | /* 0x18 4GB flat data segment */ |
| 50 | .word 0xFFFF, 0x0000, 0x9200, 0x00CF |
| 51 | gdt_end: |
| 52 | |
| 53 | .bss |
| 54 | .balign 4096 |
| 55 | lstack: |
| 56 | .skip 4096 |
| 57 | lstack_end: |