diff options
| author | Vivek Goyal <vgoyal@redhat.com> | 2014-08-08 17:26:02 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-08 18:57:32 -0400 |
| commit | 8fc5b4d4121c95482b2583a07863c6b0aba2d9e1 (patch) | |
| tree | 16ef44c15e9802c1aed83d8eead0569822268794 /arch/x86/purgatory/entry64.S | |
| parent | daeba0641a707626f3674db71016f333edf64395 (diff) | |
purgatory: core purgatory functionality
Create a stand alone relocatable object purgatory which runs between two
kernels. This name, concept and some code has been taken from
kexec-tools. Idea is that this code runs after a crash and it runs in
minimal environment. So keep it separate from rest of the kernel and in
long term we will have to practically do no maintenance of this code.
This code also has the logic to do verify sha256 hashes of various
segments which have been loaded into memory. So first we verify that the
kernel we are jumping to is fine and has not been corrupted and make
progress only if checsums are verified.
This code also takes care of copying some memory contents to backup region.
[sfr@canb.auug.org.au: run host built programs from objtree]
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 000000000000..be3249d7ed2d --- /dev/null +++ b/arch/x86/purgatory/entry64.S | |||
| @@ -0,0 +1,101 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) | ||
| 3 | * Copyright (C) 2014 Red Hat Inc. | ||
| 4 | |||
| 5 | * Author(s): Vivek Goyal <vgoyal@redhat.com> | ||
| 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 | .balign 16 | ||
| 15 | .code64 | ||
| 16 | .globl entry64, entry64_regs | ||
| 17 | |||
| 18 | |||
| 19 | entry64: | ||
| 20 | /* Setup a gdt that should be preserved */ | ||
| 21 | lgdt gdt(%rip) | ||
| 22 | |||
| 23 | /* load the data segments */ | ||
| 24 | movl $0x18, %eax /* data segment */ | ||
| 25 | movl %eax, %ds | ||
| 26 | movl %eax, %es | ||
| 27 | movl %eax, %ss | ||
| 28 | movl %eax, %fs | ||
| 29 | movl %eax, %gs | ||
| 30 | |||
| 31 | /* Setup new stack */ | ||
| 32 | leaq stack_init(%rip), %rsp | ||
| 33 | pushq $0x10 /* CS */ | ||
| 34 | leaq new_cs_exit(%rip), %rax | ||
| 35 | pushq %rax | ||
| 36 | lretq | ||
| 37 | new_cs_exit: | ||
| 38 | |||
| 39 | /* Load the registers */ | ||
| 40 | movq rax(%rip), %rax | ||
| 41 | movq rbx(%rip), %rbx | ||
| 42 | movq rcx(%rip), %rcx | ||
| 43 | movq rdx(%rip), %rdx | ||
| 44 | movq rsi(%rip), %rsi | ||
| 45 | movq rdi(%rip), %rdi | ||
| 46 | movq rsp(%rip), %rsp | ||
| 47 | movq rbp(%rip), %rbp | ||
| 48 | movq r8(%rip), %r8 | ||
| 49 | movq r9(%rip), %r9 | ||
| 50 | movq r10(%rip), %r10 | ||
| 51 | movq r11(%rip), %r11 | ||
| 52 | movq r12(%rip), %r12 | ||
| 53 | movq r13(%rip), %r13 | ||
| 54 | movq r14(%rip), %r14 | ||
| 55 | movq r15(%rip), %r15 | ||
| 56 | |||
| 57 | /* Jump to the new code... */ | ||
| 58 | jmpq *rip(%rip) | ||
| 59 | |||
| 60 | .section ".rodata" | ||
| 61 | .balign 4 | ||
| 62 | entry64_regs: | ||
| 63 | rax: .quad 0x0 | ||
| 64 | rbx: .quad 0x0 | ||
| 65 | rcx: .quad 0x0 | ||
| 66 | rdx: .quad 0x0 | ||
| 67 | rsi: .quad 0x0 | ||
| 68 | rdi: .quad 0x0 | ||
| 69 | rsp: .quad 0x0 | ||
| 70 | rbp: .quad 0x0 | ||
| 71 | r8: .quad 0x0 | ||
| 72 | r9: .quad 0x0 | ||
| 73 | r10: .quad 0x0 | ||
| 74 | r11: .quad 0x0 | ||
| 75 | r12: .quad 0x0 | ||
| 76 | r13: .quad 0x0 | ||
| 77 | r14: .quad 0x0 | ||
| 78 | r15: .quad 0x0 | ||
| 79 | rip: .quad 0x0 | ||
| 80 | .size entry64_regs, . - entry64_regs | ||
| 81 | |||
| 82 | /* GDT */ | ||
| 83 | .section ".rodata" | ||
| 84 | .balign 16 | ||
| 85 | gdt: | ||
| 86 | /* 0x00 unusable segment | ||
| 87 | * 0x08 unused | ||
| 88 | * so use them as gdt ptr | ||
| 89 | */ | ||
| 90 | .word gdt_end - gdt - 1 | ||
| 91 | .quad gdt | ||
| 92 | .word 0, 0, 0 | ||
| 93 | |||
| 94 | /* 0x10 4GB flat code segment */ | ||
| 95 | .word 0xFFFF, 0x0000, 0x9A00, 0x00AF | ||
| 96 | |||
| 97 | /* 0x18 4GB flat data segment */ | ||
| 98 | .word 0xFFFF, 0x0000, 0x9200, 0x00CF | ||
| 99 | gdt_end: | ||
| 100 | stack: .quad 0, 0 | ||
| 101 | stack_init: | ||