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