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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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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>
129 lines
2.9 KiB
ArmAsm
129 lines
2.9 KiB
ArmAsm
/*
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* kexec trampoline
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*
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* Based on code taken from kexec-tools and kexec-lite.
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*
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* Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
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* Copyright (C) 2006, Mohan Kumar M, IBM Corporation
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* Copyright (C) 2013, Anton Blanchard, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify it under
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* the terms of the GNU General Public License as published by the Free
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* Software Foundation (version 2 of the License).
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*/
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#if defined(__LITTLE_ENDIAN__)
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#define STWX_BE stwbrx
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#define LWZX_BE lwbrx
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#elif defined(__BIG_ENDIAN__)
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#define STWX_BE stwx
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#define LWZX_BE lwzx
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#else
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#error no endianness defined!
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#endif
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.machine ppc64
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.balign 256
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.globl purgatory_start
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purgatory_start:
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b master
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/* ABI: possible run_at_load flag at 0x5c */
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.org purgatory_start + 0x5c
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.globl run_at_load
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run_at_load:
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.long 0
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.size run_at_load, . - run_at_load
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/* ABI: slaves start at 60 with r3=phys */
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.org purgatory_start + 0x60
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slave:
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b .
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/* ABI: end of copied region */
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.org purgatory_start + 0x100
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.size purgatory_start, . - purgatory_start
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/*
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* The above 0x100 bytes at purgatory_start are replaced with the
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* code from the kernel (or next stage) by setup_purgatory().
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*/
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master:
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or %r1,%r1,%r1 /* low priority to let other threads catchup */
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isync
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mr %r17,%r3 /* save cpu id to r17 */
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mr %r15,%r4 /* save physical address in reg15 */
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or %r3,%r3,%r3 /* ok now to high priority, lets boot */
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lis %r6,0x1
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mtctr %r6 /* delay a bit for slaves to catch up */
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bdnz . /* before we overwrite 0-100 again */
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bl 0f /* Work out where we're running */
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0: mflr %r18
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/* load device-tree address */
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ld %r3, (dt_offset - 0b)(%r18)
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mr %r16,%r3 /* save dt address in reg16 */
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li %r4,20
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LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */
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cmpwi %r0,%r6,2 /* v2 or later? */
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blt 1f
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li %r4,28
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STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */
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1:
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/* load the kernel address */
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ld %r4,(kernel - 0b)(%r18)
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/* load the run_at_load flag */
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/* possibly patched by kexec */
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ld %r6,(run_at_load - 0b)(%r18)
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/* and patch it into the kernel */
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stw %r6,(0x5c)(%r4)
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mr %r3,%r16 /* restore dt address */
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li %r5,0 /* r5 will be 0 for kernel */
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mfmsr %r11
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andi. %r10,%r11,1 /* test MSR_LE */
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bne .Little_endian
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mtctr %r4 /* prepare branch to */
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bctr /* start kernel */
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.Little_endian:
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mtsrr0 %r4 /* prepare branch to */
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clrrdi %r11,%r11,1 /* clear MSR_LE */
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mtsrr1 %r11
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rfid /* update MSR and start kernel */
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.balign 8
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.globl kernel
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kernel:
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.llong 0x0
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.size kernel, . - kernel
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.balign 8
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.globl dt_offset
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dt_offset:
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.llong 0x0
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.size dt_offset, . - dt_offset
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.data
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.balign 8
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.globl purgatory_sha256_digest
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purgatory_sha256_digest:
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.skip 32
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.size purgatory_sha256_digest, . - purgatory_sha256_digest
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.balign 8
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.globl purgatory_sha_regions
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purgatory_sha_regions:
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.skip 8 * 2 * 16
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.size purgatory_sha_regions, . - purgatory_sha_regions
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