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
27ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
28 unsigned long offset);
29ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
30 size_t csize, unsigned long offset);
31
32void 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
63static 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
76static 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
85static 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 */
108struct vmcore_cb {
109 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
110 struct list_head next;
111};
112extern void register_vmcore_cb(struct vmcore_cb *cb);
113extern void unregister_vmcore_cb(struct vmcore_cb *cb);
114
115#else /* !CONFIG_CRASH_DUMP */
116static inline bool is_kdump_kernel(void) { return false; }
117#endif /* CONFIG_CRASH_DUMP */
118
119/* Device Dump information to be filled by drivers */
120struct 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
128int vmcore_add_device_dump(struct vmcoredd_data *data);
129#else
130static 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
137ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
138 u64 *ppos, bool encrypted);
139#else
140static 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

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