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| author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
|---|---|---|
| committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
| commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
| tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/x86/purgatory/entry64.S | |
Initial import
Diffstat (limited to 'arch/x86/purgatory/entry64.S')
| -rw-r--r-- | arch/x86/purgatory/entry64.S | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/arch/x86/purgatory/entry64.S b/arch/x86/purgatory/entry64.S new file mode 100644 index 000000000..d1a4291d3 --- /dev/null +++ b/arch/x86/purgatory/entry64.S @@ -0,0 +1,101 @@ +/* + * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) + * Copyright (C) 2014 Red Hat Inc. + + * Author(s): Vivek Goyal <vgoyal@redhat.com> + * + * This code has been taken from kexec-tools. + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + + .text + .balign 16 + .code64 + .globl entry64, entry64_regs + + +entry64: + /* Setup a gdt that should be preserved */ + 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 new stack */ + leaq stack_init(%rip), %rsp + pushq $0x10 /* CS */ + leaq new_cs_exit(%rip), %rax + pushq %rax + lretq +new_cs_exit: + + /* Load the registers */ + movq rax(%rip), %rax + movq rbx(%rip), %rbx + movq rcx(%rip), %rcx + movq rdx(%rip), %rdx + movq rsi(%rip), %rsi + movq rdi(%rip), %rdi + movq rsp(%rip), %rsp + movq rbp(%rip), %rbp + movq r8(%rip), %r8 + movq r9(%rip), %r9 + movq r10(%rip), %r10 + movq r11(%rip), %r11 + movq r12(%rip), %r12 + movq r13(%rip), %r13 + movq r14(%rip), %r14 + movq r15(%rip), %r15 + + /* Jump to the new code... */ + jmpq *rip(%rip) + + .section ".rodata" + .balign 4 +entry64_regs: +rax: .quad 0x0 +rcx: .quad 0x0 +rdx: .quad 0x0 +rbx: .quad 0x0 +rsp: .quad 0x0 +rbp: .quad 0x0 +rsi: .quad 0x0 +rdi: .quad 0x0 +r8: .quad 0x0 +r9: .quad 0x0 +r10: .quad 0x0 +r11: .quad 0x0 +r12: .quad 0x0 +r13: .quad 0x0 +r14: .quad 0x0 +r15: .quad 0x0 +rip: .quad 0x0 + .size entry64_regs, . - entry64_regs + + /* GDT */ + .section ".rodata" + .balign 16 +gdt: + /* 0x00 unusable segment + * 0x08 unused + * so use them as 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 +gdt_end: +stack: .quad 0, 0 +stack_init: |