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 /* For IS_ENABLED(CONFIG_CRASH_DUMP) */
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 #ifdef CONFIG_CRASH_DUMP
19 extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
20 extern void elfcorehdr_free(unsigned long long addr);
21 extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
22 extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
23 extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
24 unsigned long from, unsigned long pfn,
25 unsigned long size, pgprot_t prot);
26
27 ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
28 unsigned long offset);
29 ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
30 size_t csize, unsigned long offset);
31
32 void vmcore_cleanup(void);
33
34 /* Architecture code defines this if there are other possible ELF
35 * machine types, e.g. on bi-arch capable hardware. */
36 #ifndef vmcore_elf_check_arch_cross
37 #define vmcore_elf_check_arch_cross(x) 0
38 #endif
39
40 /*
41 * Architecture code can redefine this if there are any special checks
42 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
43 * only architecture, vmcore_elf64_check_arch can be set to zero.
44 */
45 #ifndef vmcore_elf32_check_arch
46 #define vmcore_elf32_check_arch(x) elf_check_arch(x)
47 #endif
48
49 #ifndef vmcore_elf64_check_arch
50 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
51 #endif
52
53 #ifndef is_kdump_kernel
54 /*
55 * is_kdump_kernel() checks whether this kernel is booting after a panic of
56 * previous kernel or not. This is determined by checking if previous kernel
57 * has passed the elf core header address on command line.
58 *
59 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
60 * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
61 * of previous kernel.
62 */
63
64 static inline bool is_kdump_kernel(void)
65 {
66 return elfcorehdr_addr != ELFCORE_ADDR_MAX;
67 }
68 #endif
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
78 static inline int is_vmcore_usable(void)
79 {
80 return elfcorehdr_addr != ELFCORE_ADDR_ERR &&
81 elfcorehdr_addr != ELFCORE_ADDR_MAX ? 1 : 0;
82 }
83
84 /* vmcore_unusable() marks the vmcore as unusable,
85 * without disturbing the logic of is_kdump_kernel()
86 */
87
88 static inline void vmcore_unusable(void)
89 {
90 elfcorehdr_addr = ELFCORE_ADDR_ERR;
91 }
92
93 /**
94 * struct vmcore_cb - driver callbacks for /proc/vmcore handling
95 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
96 * reading the vmcore. Will return "true" if it is RAM or if the
97 * callback cannot tell. If any callback returns "false", it's not
98 * RAM and the page must not be accessed; zeroes should be
99 * indicated in the vmcore instead. For example, a ballooned page
100 * contains no data and reading from such a page will cause high
101 * load in the hypervisor.
102 * @next: List head to manage registered callbacks internally; initialized by
103 * register_vmcore_cb().
104 *
105 * vmcore callbacks allow drivers managing physical memory ranges to
106 * coordinate with vmcore handling code, for example, to prevent accessing
107 * physical memory ranges that should not be accessed when reading the vmcore,
108 * although included in the vmcore header as memory ranges to dump.
109 */
110 struct vmcore_cb {
111 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
112 struct list_head next;
113 };
114 extern void register_vmcore_cb(struct vmcore_cb *cb);
115 extern void unregister_vmcore_cb(struct vmcore_cb *cb);
116
117 #else /* !CONFIG_CRASH_DUMP */
118 static inline bool is_kdump_kernel(void) { return false; }
119 #endif /* CONFIG_CRASH_DUMP */
120
121 /* Device Dump information to be filled by drivers */
122 struct vmcoredd_data {
123 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
124 unsigned int size; /* Size of the dump */
125 /* Driver's registered callback to be invoked to collect dump */
126 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
127 };
128
129 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
130 int vmcore_add_device_dump(struct vmcoredd_data *data);
131 #else
132 static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
133 {
134 return -EOPNOTSUPP;
135 }
136 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
137
138 #ifdef CONFIG_PROC_VMCORE
139 ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
140 u64 *ppos, bool encrypted);
141 #else
142 static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
143 u64 *ppos, bool encrypted)
144 {
145 return -EOPNOTSUPP;
146 }
147 #endif /* CONFIG_PROC_VMCORE */
148
149 #endif /* LINUX_CRASHDUMP_H */
150
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