LXR linux/include/linux/crash

   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#include <linux/pgtable.h> /* for pgprot_t */
  12
  13/* For IS_ENABLED(CONFIG_CRASH_DUMP) */
  14#define ELFCORE_ADDR_MAX        (-1ULL)
  15#define ELFCORE_ADDR_ERR        (-2ULL)
  16
  17extern unsigned long long elfcorehdr_addr;
  18extern unsigned long long elfcorehdr_size;
  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);
  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
  29extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  30                                                unsigned long, int);
  31extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
  32                                          size_t csize, unsigned long offset,
  33                                          int userbuf);
  34
  35void vmcore_cleanup(void);
  36
  37/* Architecture code defines this if there are other possible ELF
  38 * machine types, e.g. on bi-arch capable hardware. */
  39#ifndef vmcore_elf_check_arch_cross
  40#define vmcore_elf_check_arch_cross(x) 0
  41#endif
  42
  43/*
  44 * Architecture code can redefine this if there are any special checks
  45 * needed for 32-bit ELF or 64-bit ELF vmcores.  In case of 32-bit
  46 * only architecture, vmcore_elf64_check_arch can be set to zero.
  47 */
  48#ifndef vmcore_elf32_check_arch
  49#define vmcore_elf32_check_arch(x) elf_check_arch(x)
  50#endif
  51
  52#ifndef vmcore_elf64_check_arch
  53#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  54#endif
  55
  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
  71/* is_vmcore_usable() checks if the kernel is booting after a panic and
  72 * the vmcore region is usable.
  73 *
  74 * This makes use of the fact that due to alignment -2ULL is not
  75 * a valid pointer, much in the vain of IS_ERR(), except
  76 * dealing directly with an unsigned long long rather than a pointer.
  77 */
  78
  79static inline int is_vmcore_usable(void)
  80{
  81        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  82}
  83
  84/* vmcore_unusable() marks the vmcore as unusable,
  85 * without disturbing the logic of is_kdump_kernel()
  86 */
  87
  88static inline void vmcore_unusable(void)
  89{
  90        if (is_kdump_kernel())
  91                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  92}
  93
  94#define HAVE_OLDMEM_PFN_IS_RAM 1
  95extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  96extern void unregister_oldmem_pfn_is_ram(void);
  97
  98#else /* !CONFIG_CRASH_DUMP */
  99static inline bool is_kdump_kernel(void) { return 0; }
 100#endif /* CONFIG_CRASH_DUMP */
 101
 102/* Device Dump information to be filled by drivers */
 103struct vmcoredd_data {
 104        char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
 105        unsigned int size;                       /* Size of the dump */
 106        /* Driver's registered callback to be invoked to collect dump */
 107        int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
 108};
 109
 110#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
 111int vmcore_add_device_dump(struct vmcoredd_data *data);
 112#else
 113static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
 114{
 115        return -EOPNOTSUPP;
 116}
 117#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 118
 119#ifdef CONFIG_PROC_VMCORE
 120ssize_t read_from_oldmem(char *buf, size_t count,
 121                         u64 *ppos, int userbuf,
 122                         bool encrypted);
 123#else
 124static inline ssize_t read_from_oldmem(char *buf, size_t count,
 125                                       u64 *ppos, int userbuf,
 126                                       bool encrypted)
 127{
 128        return -EOPNOTSUPP;
 129}
 130#endif /* CONFIG_PROC_VMCORE */
 131
 132#endif /* LINUX_CRASHDUMP_H */
 133