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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
15extern unsigned long long elfcorehdr_addr;
16extern unsigned long long elfcorehdr_size;
17
18extern unsigned long long dm_crypt_keys_addr;
19
20#ifdef CONFIG_CRASH_DUMP
21extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
22extern void elfcorehdr_free(unsigned long long addr);
23extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
24extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
25void elfcorehdr_fill_device_ram_ptload_elf64(Elf64_Phdr *phdr,
26 unsigned long long paddr, unsigned long long size);
27extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
28 unsigned long from, unsigned long pfn,
29 unsigned long size, pgprot_t prot);
30
31ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
32 unsigned long offset);
33ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
34 size_t csize, unsigned long offset);
35
36void vmcore_cleanup(void);
37
38/* Architecture code defines this if there are other possible ELF
39 * machine types, e.g. on bi-arch capable hardware. */
40#ifndef vmcore_elf_check_arch_cross
41#define vmcore_elf_check_arch_cross(x) 0
42#endif
43
44/*
45 * Architecture code can redefine this if there are any special checks
46 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
47 * only architecture, vmcore_elf64_check_arch can be set to zero.
48 */
49#ifndef vmcore_elf32_check_arch
50#define vmcore_elf32_check_arch(x) elf_check_arch(x)
51#endif
52
53#ifndef vmcore_elf64_check_arch
54#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
55#endif
56
57#ifndef is_kdump_kernel
58/*
59 * is_kdump_kernel() checks whether this kernel is booting after a panic of
60 * previous kernel or not. This is determined by checking if previous kernel
61 * has passed the elf core header address on command line.
62 *
63 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
64 * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
65 * of previous kernel.
66 */
67
68static inline bool is_kdump_kernel(void)
69{
70 return elfcorehdr_addr != ELFCORE_ADDR_MAX;
71}
72#endif
73
74/* is_vmcore_usable() checks if the kernel is booting after a panic and
75 * the vmcore region is usable.
76 *
77 * This makes use of the fact that due to alignment -2ULL is not
78 * a valid pointer, much in the vain of IS_ERR(), except
79 * dealing directly with an unsigned long long rather than a pointer.
80 */
81
82static inline int is_vmcore_usable(void)
83{
84 return elfcorehdr_addr != ELFCORE_ADDR_ERR &&
85 elfcorehdr_addr != ELFCORE_ADDR_MAX ? 1 : 0;
86}
87
88/* vmcore_unusable() marks the vmcore as unusable,
89 * without disturbing the logic of is_kdump_kernel()
90 */
91
92static inline void vmcore_unusable(void)
93{
94 elfcorehdr_addr = ELFCORE_ADDR_ERR;
95}
96
97/**
98 * struct vmcore_cb - driver callbacks for /proc/vmcore handling
99 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
100 * reading the vmcore. Will return "true" if it is RAM or if the
101 * callback cannot tell. If any callback returns "false", it's not
102 * RAM and the page must not be accessed; zeroes should be
103 * indicated in the vmcore instead. For example, a ballooned page
104 * contains no data and reading from such a page will cause high
105 * load in the hypervisor.
106 * @get_device_ram: query RAM ranges that can only be detected by device
107 * drivers, such as the virtio-mem driver, so they can be included in
108 * the crash dump on architectures that allocate the elfcore hdr in the dump
109 * ("2nd") kernel. Indicated RAM ranges may contain holes to reduce the
110 * total number of ranges; such holes can be detected using the pfn_is_ram
111 * callback just like for other RAM.
112 * @next: List head to manage registered callbacks internally; initialized by
113 * register_vmcore_cb().
114 *
115 * vmcore callbacks allow drivers managing physical memory ranges to
116 * coordinate with vmcore handling code, for example, to prevent accessing
117 * physical memory ranges that should not be accessed when reading the vmcore,
118 * although included in the vmcore header as memory ranges to dump.
119 */
120struct vmcore_cb {
121 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
122 int (*get_device_ram)(struct vmcore_cb *cb, struct list_head *list);
123 struct list_head next;
124};
125extern void register_vmcore_cb(struct vmcore_cb *cb);
126extern void unregister_vmcore_cb(struct vmcore_cb *cb);
127
128struct vmcore_range {
129 struct list_head list;
130 unsigned long long paddr;
131 unsigned long long size;
132 loff_t offset;
133};
134
135/* Allocate a vmcore range and add it to the list. */
136static inline int vmcore_alloc_add_range(struct list_head *list,
137 unsigned long long paddr, unsigned long long size)
138{
139 struct vmcore_range *m = kzalloc(sizeof(*m), GFP_KERNEL);
140
141 if (!m)
142 return -ENOMEM;
143 m->paddr = paddr;
144 m->size = size;
145 list_add_tail(new: &m->list, head: list);
146 return 0;
147}
148
149/* Free a list of vmcore ranges. */
150static inline void vmcore_free_ranges(struct list_head *list)
151{
152 struct vmcore_range *m, *tmp;
153
154 list_for_each_entry_safe(m, tmp, list, list) {
155 list_del(entry: &m->list);
156 kfree(objp: m);
157 }
158}
159
160#else /* !CONFIG_CRASH_DUMP */
161static inline bool is_kdump_kernel(void) { return false; }
162#endif /* CONFIG_CRASH_DUMP */
163
164/* Device Dump information to be filled by drivers */
165struct vmcoredd_data {
166 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
167 unsigned int size; /* Size of the dump */
168 /* Driver's registered callback to be invoked to collect dump */
169 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
170};
171
172#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
173int vmcore_add_device_dump(struct vmcoredd_data *data);
174#else
175static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
176{
177 return -EOPNOTSUPP;
178}
179#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
180
181#ifdef CONFIG_PROC_VMCORE
182ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
183 u64 *ppos, bool encrypted);
184#else
185static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
186 u64 *ppos, bool encrypted)
187{
188 return -EOPNOTSUPP;
189}
190#endif /* CONFIG_PROC_VMCORE */
191
192#endif /* LINUX_CRASHDUMP_H */
193

source code of linux/include/linux/crash_dump.h