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40c50c1fec
The purgatory code defines global variables which are referenced via a
symbol lookup in the kexec code (core and arch).
A recent commit addressing sparse warnings made these static and thereby
broke kexec_file.
Why did this happen? Simply because the whole machinery is undocumented and
lacks any form of forward declarations. The variable names are unspecific
and lack a prefix, so adding forward declarations creates shadow variables
in the core code. Aside of that the code relies on magic constants and
duplicate struct definitions with no way to ensure that these things stay
in sync. The section placement of the purgatory variables happened by
chance and not by design.
Unbreak kexec and cleanup the mess:
- Add proper forward declarations and document the usage
- Use common struct definition
- Use the proper common defines instead of magic constants
- Add a purgatory_ prefix to have a proper name space
- Use ARRAY_SIZE() instead of a homebrewn reimplementation
- Add proper sections to the purgatory variables [ From Mike ]
Fixes: 72042a8c7b ("x86/purgatory: Make functions and variables static")
Reported-by: Mike Galbraith <<efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Tobin C. Harding" <me@tobin.cc>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1703101315140.3681@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
59 lines
1.1 KiB
ArmAsm
59 lines
1.1 KiB
ArmAsm
/*
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* purgatory: setup code
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*
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* Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com)
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* Copyright (C) 2014 Red Hat Inc.
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*
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* This code has been taken from kexec-tools.
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <asm/purgatory.h>
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.text
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.globl purgatory_start
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.balign 16
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purgatory_start:
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.code64
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/* Load a gdt so I know what the segment registers are */
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lgdt gdt(%rip)
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/* load the data segments */
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movl $0x18, %eax /* data segment */
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movl %eax, %ds
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movl %eax, %es
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movl %eax, %ss
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movl %eax, %fs
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movl %eax, %gs
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/* Setup a stack */
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leaq lstack_end(%rip), %rsp
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/* Call the C code */
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call purgatory
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jmp entry64
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.section ".rodata"
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.balign 16
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gdt: /* 0x00 unusable segment
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* 0x08 unused
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* so use them as the gdt ptr
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*/
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.word gdt_end - gdt - 1
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.quad gdt
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.word 0, 0, 0
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/* 0x10 4GB flat code segment */
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.word 0xFFFF, 0x0000, 0x9A00, 0x00AF
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/* 0x18 4GB flat data segment */
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.word 0xFFFF, 0x0000, 0x9200, 0x00CF
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gdt_end:
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.bss
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.balign 4096
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lstack:
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.skip 4096
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lstack_end:
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