1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LINUX_CRASH_DUMP_H
3 #define LINUX_CRASH_DUMP_H
4
5 #ifdef CONFIG_CRASH_DUMP
6 #include <linux/kexec.h>
7 #include <linux/proc_fs.h>
8 #include <linux/elf.h>
9
10 #include <asm/pgtable.h> /* for pgprot_t */
11
12 #define ELFCORE_ADDR_MAX (-1ULL)
13 #define ELFCORE_ADDR_ERR (-2ULL)
14
15 extern unsigned long long elfcorehdr_addr;
16 extern unsigned long long elfcorehdr_size;
17
18 extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
19 extern void elfcorehdr_free(unsigned long long addr);
20 extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
21 extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
22 extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
23 unsigned long from, unsigned long pfn,
24 unsigned long size, pgprot_t prot);
25
26 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
27 unsigned long, int);
28 void vmcore_cleanup(void);
29
30 /* Architecture code defines this if there are other possible ELF
31 * machine types, e.g. on bi-arch capable hardware. */
32 #ifndef vmcore_elf_check_arch_cross
33 #define vmcore_elf_check_arch_cross(x) 0
34 #endif
35
36 /*
37 * Architecture code can redefine this if there are any special checks
38 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
39 * only architecture, vmcore_elf64_check_arch can be set to zero.
40 */
41 #ifndef vmcore_elf32_check_arch
42 #define vmcore_elf32_check_arch(x) elf_check_arch(x)
43 #endif
44
45 #ifndef vmcore_elf64_check_arch
46 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
47 #endif
48
49 /*
50 * is_kdump_kernel() checks whether this kernel is booting after a panic of
51 * previous kernel or not. This is determined by checking if previous kernel
52 * has passed the elf core header address on command line.
53 *
54 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
55 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
56 * previous kernel.
57 */
58
is_kdump_kernel(void)59 static inline int is_kdump_kernel(void)
60 {
61 return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
62 }
63
64 /* is_vmcore_usable() checks if the kernel is booting after a panic and
65 * the vmcore region is usable.
66 *
67 * This makes use of the fact that due to alignment -2ULL is not
68 * a valid pointer, much in the vain of IS_ERR(), except
69 * dealing directly with an unsigned long long rather than a pointer.
70 */
71
is_vmcore_usable(void)72 static inline int is_vmcore_usable(void)
73 {
74 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
75 }
76
77 /* vmcore_unusable() marks the vmcore as unusable,
78 * without disturbing the logic of is_kdump_kernel()
79 */
80
vmcore_unusable(void)81 static inline void vmcore_unusable(void)
82 {
83 if (is_kdump_kernel())
84 elfcorehdr_addr = ELFCORE_ADDR_ERR;
85 }
86
87 #define HAVE_OLDMEM_PFN_IS_RAM 1
88 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
89 extern void unregister_oldmem_pfn_is_ram(void);
90
91 #else /* !CONFIG_CRASH_DUMP */
is_kdump_kernel(void)92 static inline int is_kdump_kernel(void) { return 0; }
93 #endif /* CONFIG_CRASH_DUMP */
94
95 extern unsigned long saved_max_pfn;
96 #endif /* LINUX_CRASHDUMP_H */
97