crash_dump.h

  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(&m->list, 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(&m->list);
156		kfree(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 */