1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LINUX_CRASH_DUMP_H
3 #define LINUX_CRASH_DUMP_H
4 
5 #include <linux/kexec.h>
6 #include <linux/proc_fs.h>
7 #include <linux/elf.h>
8 #include <linux/pgtable.h>
9 #include <uapi/linux/vmcore.h>
10 
11 #include <linux/pgtable.h> /* for pgprot_t */
12 
13 #ifdef CONFIG_CRASH_DUMP
14 #define ELFCORE_ADDR_MAX	(-1ULL)
15 #define ELFCORE_ADDR_ERR	(-2ULL)
16 
17 extern unsigned long long elfcorehdr_addr;
18 extern unsigned long long elfcorehdr_size;
19 
20 extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
21 extern void elfcorehdr_free(unsigned long long addr);
22 extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
23 extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
24 extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
25 				  unsigned long from, unsigned long pfn,
26 				  unsigned long size, pgprot_t prot);
27 
28 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
29 						unsigned long, int);
30 extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
31 					  size_t csize, unsigned long offset,
32 					  int userbuf);
33 
34 void vmcore_cleanup(void);
35 
36 /* Architecture code defines this if there are other possible ELF
37  * machine types, e.g. on bi-arch capable hardware. */
38 #ifndef vmcore_elf_check_arch_cross
39 #define vmcore_elf_check_arch_cross(x) 0
40 #endif
41 
42 /*
43  * Architecture code can redefine this if there are any special checks
44  * needed for 32-bit ELF or 64-bit ELF vmcores.  In case of 32-bit
45  * only architecture, vmcore_elf64_check_arch can be set to zero.
46  */
47 #ifndef vmcore_elf32_check_arch
48 #define vmcore_elf32_check_arch(x) elf_check_arch(x)
49 #endif
50 
51 #ifndef vmcore_elf64_check_arch
52 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
53 #endif
54 
55 /*
56  * is_kdump_kernel() checks whether this kernel is booting after a panic of
57  * previous kernel or not. This is determined by checking if previous kernel
58  * has passed the elf core header address on command line.
59  *
60  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
61  * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
62  * of previous kernel.
63  */
64 
is_kdump_kernel(void)65 static inline bool is_kdump_kernel(void)
66 {
67 	return elfcorehdr_addr != ELFCORE_ADDR_MAX;
68 }
69 
70 /* is_vmcore_usable() checks if the kernel is booting after a panic and
71  * the vmcore region is usable.
72  *
73  * This makes use of the fact that due to alignment -2ULL is not
74  * a valid pointer, much in the vain of IS_ERR(), except
75  * dealing directly with an unsigned long long rather than a pointer.
76  */
77 
is_vmcore_usable(void)78 static inline int is_vmcore_usable(void)
79 {
80 	return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
81 }
82 
83 /* vmcore_unusable() marks the vmcore as unusable,
84  * without disturbing the logic of is_kdump_kernel()
85  */
86 
vmcore_unusable(void)87 static inline void vmcore_unusable(void)
88 {
89 	if (is_kdump_kernel())
90 		elfcorehdr_addr = ELFCORE_ADDR_ERR;
91 }
92 
93 #define HAVE_OLDMEM_PFN_IS_RAM 1
94 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
95 extern void unregister_oldmem_pfn_is_ram(void);
96 
97 #else /* !CONFIG_CRASH_DUMP */
is_kdump_kernel(void)98 static inline bool is_kdump_kernel(void) { return 0; }
99 #endif /* CONFIG_CRASH_DUMP */
100 
101 /* Device Dump information to be filled by drivers */
102 struct vmcoredd_data {
103 	char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
104 	unsigned int size;                       /* Size of the dump */
105 	/* Driver's registered callback to be invoked to collect dump */
106 	int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
107 };
108 
109 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
110 int vmcore_add_device_dump(struct vmcoredd_data *data);
111 #else
vmcore_add_device_dump(struct vmcoredd_data * data)112 static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
113 {
114 	return -EOPNOTSUPP;
115 }
116 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
117 
118 #ifdef CONFIG_PROC_VMCORE
119 ssize_t read_from_oldmem(char *buf, size_t count,
120 			 u64 *ppos, int userbuf,
121 			 bool encrypted);
122 #else
read_from_oldmem(char * buf,size_t count,u64 * ppos,int userbuf,bool encrypted)123 static inline ssize_t read_from_oldmem(char *buf, size_t count,
124 				       u64 *ppos, int userbuf,
125 				       bool encrypted)
126 {
127 	return -EOPNOTSUPP;
128 }
129 #endif /* CONFIG_PROC_VMCORE */
130 
131 #endif /* LINUX_CRASHDUMP_H */
132