150 lines
5.0 KiB
C
150 lines
5.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef LINUX_CRASH_DUMP_H
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#define LINUX_CRASH_DUMP_H
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#include <linux/kexec.h>
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#include <linux/proc_fs.h>
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#include <linux/elf.h>
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#include <linux/pgtable.h>
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#include <uapi/linux/vmcore.h>
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/* For IS_ENABLED(CONFIG_CRASH_DUMP) */
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#define ELFCORE_ADDR_MAX (-1ULL)
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#define ELFCORE_ADDR_ERR (-2ULL)
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extern unsigned long long elfcorehdr_addr;
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extern unsigned long long elfcorehdr_size;
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#ifdef CONFIG_CRASH_DUMP
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extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
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extern void elfcorehdr_free(unsigned long long addr);
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extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
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extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
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extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
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unsigned long from, unsigned long pfn,
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unsigned long size, pgprot_t prot);
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ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
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unsigned long offset);
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ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
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size_t csize, unsigned long offset);
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void vmcore_cleanup(void);
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/* Architecture code defines this if there are other possible ELF
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* machine types, e.g. on bi-arch capable hardware. */
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#ifndef vmcore_elf_check_arch_cross
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#define vmcore_elf_check_arch_cross(x) 0
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#endif
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/*
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* Architecture code can redefine this if there are any special checks
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* needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
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* only architecture, vmcore_elf64_check_arch can be set to zero.
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*/
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#ifndef vmcore_elf32_check_arch
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#define vmcore_elf32_check_arch(x) elf_check_arch(x)
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#endif
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#ifndef vmcore_elf64_check_arch
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#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
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#endif
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#ifndef is_kdump_kernel
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/*
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* is_kdump_kernel() checks whether this kernel is booting after a panic of
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* previous kernel or not. This is determined by checking if previous kernel
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* has passed the elf core header address on command line.
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*
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* This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
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* return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
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* of previous kernel.
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*/
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static inline bool is_kdump_kernel(void)
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{
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return elfcorehdr_addr != ELFCORE_ADDR_MAX;
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}
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#endif
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/* is_vmcore_usable() checks if the kernel is booting after a panic and
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* the vmcore region is usable.
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*
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* This makes use of the fact that due to alignment -2ULL is not
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* a valid pointer, much in the vain of IS_ERR(), except
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* dealing directly with an unsigned long long rather than a pointer.
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*/
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static inline int is_vmcore_usable(void)
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{
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return elfcorehdr_addr != ELFCORE_ADDR_ERR &&
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elfcorehdr_addr != ELFCORE_ADDR_MAX ? 1 : 0;
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}
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/* vmcore_unusable() marks the vmcore as unusable,
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* without disturbing the logic of is_kdump_kernel()
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*/
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static inline void vmcore_unusable(void)
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{
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elfcorehdr_addr = ELFCORE_ADDR_ERR;
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}
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/**
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* struct vmcore_cb - driver callbacks for /proc/vmcore handling
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* @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
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* reading the vmcore. Will return "true" if it is RAM or if the
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* callback cannot tell. If any callback returns "false", it's not
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* RAM and the page must not be accessed; zeroes should be
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* indicated in the vmcore instead. For example, a ballooned page
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* contains no data and reading from such a page will cause high
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* load in the hypervisor.
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* @next: List head to manage registered callbacks internally; initialized by
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* register_vmcore_cb().
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*
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* vmcore callbacks allow drivers managing physical memory ranges to
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* coordinate with vmcore handling code, for example, to prevent accessing
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* physical memory ranges that should not be accessed when reading the vmcore,
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* although included in the vmcore header as memory ranges to dump.
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*/
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struct vmcore_cb {
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bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
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struct list_head next;
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};
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extern void register_vmcore_cb(struct vmcore_cb *cb);
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extern void unregister_vmcore_cb(struct vmcore_cb *cb);
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#else /* !CONFIG_CRASH_DUMP */
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static inline bool is_kdump_kernel(void) { return false; }
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#endif /* CONFIG_CRASH_DUMP */
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/* Device Dump information to be filled by drivers */
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struct vmcoredd_data {
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char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
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unsigned int size; /* Size of the dump */
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/* Driver's registered callback to be invoked to collect dump */
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int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
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};
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#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
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int vmcore_add_device_dump(struct vmcoredd_data *data);
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#else
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static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
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{
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return -EOPNOTSUPP;
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}
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#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
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#ifdef CONFIG_PROC_VMCORE
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ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
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u64 *ppos, bool encrypted);
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#else
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static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
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u64 *ppos, bool encrypted)
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{
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return -EOPNOTSUPP;
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}
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#endif /* CONFIG_PROC_VMCORE */
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#endif /* LINUX_CRASHDUMP_H */
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