forked from Minki/linux
54622f10a6
This adds relocatable kernel support for kdump. With this one can use the same regular kernel to capture the kdump. A signature (0xfeed1234) is passed in r6 from panic code to the next kernel through kexec_sequence and purgatory code. The signature is used to differentiate between kdump kernel and non-kdump kernels. The purgatory code compares the signature and sets the __kdump_flag in head_64.S. During the boot up, kernel code checks __kdump_flag and if it is set, the kernel will behave as relocatable kdump kernel. This kernel will boot at the address where it was loaded by kexec-tools ie. at the address reserved through crashkernel boot parameter. CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump kernel as relocatable. So the same kernel can be used as production and kdump kernel. This patch incorporates the changes suggested by Paul Mackerras to avoid GOT use and to avoid two copies of the code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
#ifndef _PPC64_KDUMP_H
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#define _PPC64_KDUMP_H
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/* Kdump kernel runs at 32 MB, change at your peril. */
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#define KDUMP_KERNELBASE 0x2000000
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/* How many bytes to reserve at zero for kdump. The reserve limit should
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* be greater or equal to the trampoline's end address.
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* Reserve to the end of the FWNMI area, see head_64.S */
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#define KDUMP_RESERVE_LIMIT 0x10000 /* 64K */
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/*
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* Used to differentiate between relocatable kdump kernel and other
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* kernels
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*/
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#define KDUMP_SIGNATURE 0xfeed1234
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#ifdef CONFIG_CRASH_DUMP
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#define KDUMP_TRAMPOLINE_START 0x0100
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#define KDUMP_TRAMPOLINE_END 0x3000
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#define KDUMP_MIN_TCE_ENTRIES 2048
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#endif /* CONFIG_CRASH_DUMP */
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#ifndef __ASSEMBLY__
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extern unsigned long __kdump_flag;
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#if defined(CONFIG_CRASH_DUMP) && !defined(CONFIG_RELOCATABLE)
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extern void reserve_kdump_trampoline(void);
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extern void setup_kdump_trampoline(void);
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#else
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/* !CRASH_DUMP || RELOCATABLE */
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static inline void reserve_kdump_trampoline(void) { ; }
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static inline void setup_kdump_trampoline(void) { ; }
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __PPC64_KDUMP_H */
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