| Vivek Goyal | 8fc5b4d | 2014-08-08 14:26:02 -0700 | [diff] [blame] | 1 | /* |
| 2 | * purgatory: setup code |
| 3 | * |
| 4 | * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) |
| 5 | * Copyright (C) 2014 Red Hat Inc. |
| 6 | * |
| 7 | * This code has been taken from kexec-tools. |
| 8 | * |
| 9 | * This source code is licensed under the GNU General Public License, |
| 10 | * Version 2. See the file COPYING for more details. |
| 11 | */ |
| 12 | |
| 13 | .text |
| 14 | .globl purgatory_start |
| 15 | .balign 16 |
| 16 | purgatory_start: |
| 17 | .code64 |
| 18 | |
| 19 | /* Load a gdt so I know what the segment registers are */ |
| 20 | lgdt gdt(%rip) |
| 21 | |
| 22 | /* load the data segments */ |
| 23 | movl $0x18, %eax /* data segment */ |
| 24 | movl %eax, %ds |
| 25 | movl %eax, %es |
| 26 | movl %eax, %ss |
| 27 | movl %eax, %fs |
| 28 | movl %eax, %gs |
| 29 | |
| 30 | /* Setup a stack */ |
| 31 | leaq lstack_end(%rip), %rsp |
| 32 | |
| 33 | /* Call the C code */ |
| 34 | call purgatory |
| 35 | jmp entry64 |
| 36 | |
| 37 | .section ".rodata" |
| 38 | .balign 16 |
| 39 | gdt: /* 0x00 unusable segment |
| 40 | * 0x08 unused |
| 41 | * so use them as the gdt ptr |
| 42 | */ |
| 43 | .word gdt_end - gdt - 1 |
| 44 | .quad gdt |
| 45 | .word 0, 0, 0 |
| 46 | |
| 47 | /* 0x10 4GB flat code segment */ |
| 48 | .word 0xFFFF, 0x0000, 0x9A00, 0x00AF |
| 49 | |
| 50 | /* 0x18 4GB flat data segment */ |
| 51 | .word 0xFFFF, 0x0000, 0x9200, 0x00CF |
| 52 | gdt_end: |
| 53 | |
| 54 | .bss |
| 55 | .balign 4096 |
| 56 | lstack: |
| 57 | .skip 4096 |
| 58 | lstack_end: |