diff options
Diffstat (limited to 'arch/x86/purgatory/setup-x86_64.S')
| -rw-r--r-- | arch/x86/purgatory/setup-x86_64.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/purgatory/setup-x86_64.S b/arch/x86/purgatory/setup-x86_64.S new file mode 100644 index 000000000..89d9e9e53 --- /dev/null +++ b/arch/x86/purgatory/setup-x86_64.S @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * purgatory: setup code + * + * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) + * Copyright (C) 2014 Red Hat Inc. + * + * This code has been taken from kexec-tools. + */ +#include <linux/linkage.h> +#include <asm/purgatory.h> + + .text + .balign 16 + .code64 + +SYM_CODE_START(purgatory_start) + /* Load a gdt so I know what the segment registers are */ + lgdt gdt(%rip) + + /* load the data segments */ + movl $0x18, %eax /* data segment */ + movl %eax, %ds + movl %eax, %es + movl %eax, %ss + movl %eax, %fs + movl %eax, %gs + + /* Setup a stack */ + leaq lstack_end(%rip), %rsp + + /* Call the C code */ + call purgatory + jmp entry64 +SYM_CODE_END(purgatory_start) + + .section ".rodata" + .balign 16 +SYM_DATA_START_LOCAL(gdt) + /* 0x00 unusable segment + * 0x08 unused + * so use them as the gdt ptr + */ + .word gdt_end - gdt - 1 + .quad gdt + .word 0, 0, 0 + + /* 0x10 4GB flat code segment */ + .word 0xFFFF, 0x0000, 0x9A00, 0x00AF + + /* 0x18 4GB flat data segment */ + .word 0xFFFF, 0x0000, 0x9200, 0x00CF +SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) + + .bss + .balign 4096 +SYM_DATA_START_LOCAL(lstack) + .skip 4096 +SYM_DATA_END_LABEL(lstack, SYM_L_LOCAL, lstack_end) |