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 | /* |
54 | * is_kdump_kernel() checks whether this kernel is booting after a panic of |
55 | * previous kernel or not. This is determined by checking if previous kernel |
56 | * has passed the elf core header address on command line. |
57 | * |
58 | * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will |
59 | * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic |
60 | * of previous kernel. |
61 | */ |
62 | |
63 | static inline bool is_kdump_kernel(void) |
64 | { |
65 | return elfcorehdr_addr != ELFCORE_ADDR_MAX; |
66 | } |
67 | |
68 | /* is_vmcore_usable() checks if the kernel is booting after a panic and |
69 | * the vmcore region is usable. |
70 | * |
71 | * This makes use of the fact that due to alignment -2ULL is not |
72 | * a valid pointer, much in the vain of IS_ERR(), except |
73 | * dealing directly with an unsigned long long rather than a pointer. |
74 | */ |
75 | |
76 | static inline int is_vmcore_usable(void) |
77 | { |
78 | return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; |
79 | } |
80 | |
81 | /* vmcore_unusable() marks the vmcore as unusable, |
82 | * without disturbing the logic of is_kdump_kernel() |
83 | */ |
84 | |
85 | static inline void vmcore_unusable(void) |
86 | { |
87 | if (is_kdump_kernel()) |
88 | elfcorehdr_addr = ELFCORE_ADDR_ERR; |
89 | } |
90 | |
91 | /** |
92 | * struct vmcore_cb - driver callbacks for /proc/vmcore handling |
93 | * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when |
94 | * reading the vmcore. Will return "true" if it is RAM or if the |
95 | * callback cannot tell. If any callback returns "false", it's not |
96 | * RAM and the page must not be accessed; zeroes should be |
97 | * indicated in the vmcore instead. For example, a ballooned page |
98 | * contains no data and reading from such a page will cause high |
99 | * load in the hypervisor. |
100 | * @next: List head to manage registered callbacks internally; initialized by |
101 | * register_vmcore_cb(). |
102 | * |
103 | * vmcore callbacks allow drivers managing physical memory ranges to |
104 | * coordinate with vmcore handling code, for example, to prevent accessing |
105 | * physical memory ranges that should not be accessed when reading the vmcore, |
106 | * although included in the vmcore header as memory ranges to dump. |
107 | */ |
108 | struct vmcore_cb { |
109 | bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn); |
110 | struct list_head next; |
111 | }; |
112 | extern void register_vmcore_cb(struct vmcore_cb *cb); |
113 | extern void unregister_vmcore_cb(struct vmcore_cb *cb); |
114 | |
115 | #else /* !CONFIG_CRASH_DUMP */ |
116 | static inline bool is_kdump_kernel(void) { return false; } |
117 | #endif /* CONFIG_CRASH_DUMP */ |
118 | |
119 | /* Device Dump information to be filled by drivers */ |
120 | struct vmcoredd_data { |
121 | char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */ |
122 | unsigned int size; /* Size of the dump */ |
123 | /* Driver's registered callback to be invoked to collect dump */ |
124 | int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf); |
125 | }; |
126 | |
127 | #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP |
128 | int vmcore_add_device_dump(struct vmcoredd_data *data); |
129 | #else |
130 | static inline int vmcore_add_device_dump(struct vmcoredd_data *data) |
131 | { |
132 | return -EOPNOTSUPP; |
133 | } |
134 | #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ |
135 | |
136 | #ifdef CONFIG_PROC_VMCORE |
137 | ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, |
138 | u64 *ppos, bool encrypted); |
139 | #else |
140 | static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, |
141 | u64 *ppos, bool encrypted) |
142 | { |
143 | return -EOPNOTSUPP; |
144 | } |
145 | #endif /* CONFIG_PROC_VMCORE */ |
146 | |
147 | #endif /* LINUX_CRASHDUMP_H */ |
148 | |