Linux 2.6.37-rc4
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / linux / crash_dump.h
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1#ifndef LINUX_CRASH_DUMP_H
2#define LINUX_CRASH_DUMP_H
3
4#ifdef CONFIG_CRASH_DUMP
5#include <linux/kexec.h>
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6#include <linux/device.h>
7#include <linux/proc_fs.h>
8
666bfddb 9#define ELFCORE_ADDR_MAX (-1ULL)
85a0ee34 10#define ELFCORE_ADDR_ERR (-2ULL)
36ac2617 11
2030eae5 12extern unsigned long long elfcorehdr_addr;
36ac2617 13
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14extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
15 unsigned long, int);
666bfddb 16
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17/* Architecture code defines this if there are other possible ELF
18 * machine types, e.g. on bi-arch capable hardware. */
19#ifndef vmcore_elf_check_arch_cross
20#define vmcore_elf_check_arch_cross(x) 0
21#endif
22
23#define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
24
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25/*
26 * is_kdump_kernel() checks whether this kernel is booting after a panic of
27 * previous kernel or not. This is determined by checking if previous kernel
28 * has passed the elf core header address on command line.
29 *
30 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
31 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
32 * previous kernel.
33 */
34
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35static inline int is_kdump_kernel(void)
36{
37 return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
38}
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39
40/* is_vmcore_usable() checks if the kernel is booting after a panic and
41 * the vmcore region is usable.
42 *
43 * This makes use of the fact that due to alignment -2ULL is not
44 * a valid pointer, much in the vain of IS_ERR(), except
45 * dealing directly with an unsigned long long rather than a pointer.
46 */
47
48static inline int is_vmcore_usable(void)
49{
50 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
51}
52
53/* vmcore_unusable() marks the vmcore as unusable,
54 * without disturbing the logic of is_kdump_kernel()
55 */
56
57static inline void vmcore_unusable(void)
58{
59 if (is_kdump_kernel())
60 elfcorehdr_addr = ELFCORE_ADDR_ERR;
61}
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62#else /* !CONFIG_CRASH_DUMP */
63static inline int is_kdump_kernel(void) { return 0; }
60e64d46 64#endif /* CONFIG_CRASH_DUMP */
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65
66extern unsigned long saved_max_pfn;
60e64d46 67#endif /* LINUX_CRASHDUMP_H */