Linux kernel mirror (for testing)
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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
18#ifdef CONFIG_CRASH_DUMP
19extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
20extern void elfcorehdr_free(unsigned long long addr);
21extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
22extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
23extern 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
27extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
28 unsigned long, int);
29extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
30 size_t csize, unsigned long offset,
31 int userbuf);
32
33void vmcore_cleanup(void);
34
35/* Architecture code defines this if there are other possible ELF
36 * machine types, e.g. on bi-arch capable hardware. */
37#ifndef vmcore_elf_check_arch_cross
38#define vmcore_elf_check_arch_cross(x) 0
39#endif
40
41/*
42 * Architecture code can redefine this if there are any special checks
43 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
44 * only architecture, vmcore_elf64_check_arch can be set to zero.
45 */
46#ifndef vmcore_elf32_check_arch
47#define vmcore_elf32_check_arch(x) elf_check_arch(x)
48#endif
49
50#ifndef vmcore_elf64_check_arch
51#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
52#endif
53
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
64static inline bool is_kdump_kernel(void)
65{
66 return elfcorehdr_addr != ELFCORE_ADDR_MAX;
67}
68
69/* is_vmcore_usable() checks if the kernel is booting after a panic and
70 * the vmcore region is usable.
71 *
72 * This makes use of the fact that due to alignment -2ULL is not
73 * a valid pointer, much in the vain of IS_ERR(), except
74 * dealing directly with an unsigned long long rather than a pointer.
75 */
76
77static inline int is_vmcore_usable(void)
78{
79 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
80}
81
82/* vmcore_unusable() marks the vmcore as unusable,
83 * without disturbing the logic of is_kdump_kernel()
84 */
85
86static inline void vmcore_unusable(void)
87{
88 if (is_kdump_kernel())
89 elfcorehdr_addr = ELFCORE_ADDR_ERR;
90}
91
92/**
93 * struct vmcore_cb - driver callbacks for /proc/vmcore handling
94 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
95 * reading the vmcore. Will return "true" if it is RAM or if the
96 * callback cannot tell. If any callback returns "false", it's not
97 * RAM and the page must not be accessed; zeroes should be
98 * indicated in the vmcore instead. For example, a ballooned page
99 * contains no data and reading from such a page will cause high
100 * load in the hypervisor.
101 * @next: List head to manage registered callbacks internally; initialized by
102 * register_vmcore_cb().
103 *
104 * vmcore callbacks allow drivers managing physical memory ranges to
105 * coordinate with vmcore handling code, for example, to prevent accessing
106 * physical memory ranges that should not be accessed when reading the vmcore,
107 * although included in the vmcore header as memory ranges to dump.
108 */
109struct vmcore_cb {
110 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
111 struct list_head next;
112};
113extern void register_vmcore_cb(struct vmcore_cb *cb);
114extern void unregister_vmcore_cb(struct vmcore_cb *cb);
115
116#else /* !CONFIG_CRASH_DUMP */
117static inline bool is_kdump_kernel(void) { return false; }
118#endif /* CONFIG_CRASH_DUMP */
119
120/* Device Dump information to be filled by drivers */
121struct vmcoredd_data {
122 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
123 unsigned int size; /* Size of the dump */
124 /* Driver's registered callback to be invoked to collect dump */
125 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
126};
127
128#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
129int vmcore_add_device_dump(struct vmcoredd_data *data);
130#else
131static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
132{
133 return -EOPNOTSUPP;
134}
135#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
136
137#ifdef CONFIG_PROC_VMCORE
138ssize_t read_from_oldmem(char *buf, size_t count,
139 u64 *ppos, int userbuf,
140 bool encrypted);
141#else
142static inline ssize_t read_from_oldmem(char *buf, size_t count,
143 u64 *ppos, int userbuf,
144 bool encrypted)
145{
146 return -EOPNOTSUPP;
147}
148#endif /* CONFIG_PROC_VMCORE */
149
150#endif /* LINUX_CRASHDUMP_H */