Linux Kernel  3.7.1
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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>
6 #include <linux/proc_fs.h>
7 #include <linux/elf.h>
8 
9 #define ELFCORE_ADDR_MAX (-1ULL)
10 #define ELFCORE_ADDR_ERR (-2ULL)
11 
12 extern unsigned long long elfcorehdr_addr;
13 extern unsigned long long elfcorehdr_size;
14 
15 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
16  unsigned long, int);
17 
18 /* Architecture code defines this if there are other possible ELF
19  * machine types, e.g. on bi-arch capable hardware. */
20 #ifndef vmcore_elf_check_arch_cross
21 #define vmcore_elf_check_arch_cross(x) 0
22 #endif
23 
24 /*
25  * Architecture code can redefine this if there are any special checks
26  * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
27  * this can be set to zero.
28  */
29 #ifndef vmcore_elf64_check_arch
30 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
31 #endif
32 
33 /*
34  * is_kdump_kernel() checks whether this kernel is booting after a panic of
35  * previous kernel or not. This is determined by checking if previous kernel
36  * has passed the elf core header address on command line.
37  *
38  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
39  * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
40  * previous kernel.
41  */
42 
43 static inline int is_kdump_kernel(void)
44 {
45  return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
46 }
47 
48 /* is_vmcore_usable() checks if the kernel is booting after a panic and
49  * the vmcore region is usable.
50  *
51  * This makes use of the fact that due to alignment -2ULL is not
52  * a valid pointer, much in the vain of IS_ERR(), except
53  * dealing directly with an unsigned long long rather than a pointer.
54  */
55 
56 static inline int is_vmcore_usable(void)
57 {
58  return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
59 }
60 
61 /* vmcore_unusable() marks the vmcore as unusable,
62  * without disturbing the logic of is_kdump_kernel()
63  */
64 
65 static inline void vmcore_unusable(void)
66 {
67  if (is_kdump_kernel())
68  elfcorehdr_addr = ELFCORE_ADDR_ERR;
69 }
70 
71 #define HAVE_OLDMEM_PFN_IS_RAM 1
72 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
73 extern void unregister_oldmem_pfn_is_ram(void);
74 
75 #else /* !CONFIG_CRASH_DUMP */
76 static inline int is_kdump_kernel(void) { return 0; }
77 #endif /* CONFIG_CRASH_DUMP */
78 
79 extern unsigned long saved_max_pfn;
80 #endif /* LINUX_CRASHDUMP_H */