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/device.h>
7 #include <linux/proc_fs.h>
8 #include <linux/elf.h>
9 
10 #define ELFCORE_ADDR_MAX	(-1ULL)
11 #define ELFCORE_ADDR_ERR	(-2ULL)
12 
13 extern unsigned long long elfcorehdr_addr;
14 extern unsigned long long elfcorehdr_size;
15 
16 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
17 						unsigned long, int);
18 
19 /* Architecture code defines this if there are other possible ELF
20  * machine types, e.g. on bi-arch capable hardware. */
21 #ifndef vmcore_elf_check_arch_cross
22 #define vmcore_elf_check_arch_cross(x) 0
23 #endif
24 
25 /*
26  * Architecture code can redefine this if there are any special checks
27  * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
28  * this can be set to zero.
29  */
30 #ifndef vmcore_elf64_check_arch
31 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
32 #endif
33 
34 /*
35  * is_kdump_kernel() checks whether this kernel is booting after a panic of
36  * previous kernel or not. This is determined by checking if previous kernel
37  * has passed the elf core header address on command line.
38  *
39  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
40  * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
41  * previous kernel.
42  */
43 
is_kdump_kernel(void)44 static inline int is_kdump_kernel(void)
45 {
46 	return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
47 }
48 
49 /* is_vmcore_usable() checks if the kernel is booting after a panic and
50  * the vmcore region is usable.
51  *
52  * This makes use of the fact that due to alignment -2ULL is not
53  * a valid pointer, much in the vain of IS_ERR(), except
54  * dealing directly with an unsigned long long rather than a pointer.
55  */
56 
is_vmcore_usable(void)57 static inline int is_vmcore_usable(void)
58 {
59 	return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
60 }
61 
62 /* vmcore_unusable() marks the vmcore as unusable,
63  * without disturbing the logic of is_kdump_kernel()
64  */
65 
vmcore_unusable(void)66 static inline void vmcore_unusable(void)
67 {
68 	if (is_kdump_kernel())
69 		elfcorehdr_addr = ELFCORE_ADDR_ERR;
70 }
71 
72 #define HAVE_OLDMEM_PFN_IS_RAM 1
73 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
74 extern void unregister_oldmem_pfn_is_ram(void);
75 
76 #else /* !CONFIG_CRASH_DUMP */
is_kdump_kernel(void)77 static inline int is_kdump_kernel(void) { return 0; }
78 #endif /* CONFIG_CRASH_DUMP */
79 
80 extern unsigned long saved_max_pfn;
81 #endif /* LINUX_CRASHDUMP_H */
82