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
   9#include <asm/pgtable.h> /* for pgprot_t */
  10
  11#ifdef 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 int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
  19extern void elfcorehdr_free(unsigned long long addr);
  20extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
  21extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
  22extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
  23                                  unsigned long from, unsigned long pfn,
  24                                  unsigned long size, pgprot_t prot);
  25
  26extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  27                                                unsigned long, int);
  28void vmcore_cleanup(void);
  29
  30/* Architecture code defines this if there are other possible ELF
  31 * machine types, e.g. on bi-arch capable hardware. */
  32#ifndef vmcore_elf_check_arch_cross
  33#define vmcore_elf_check_arch_cross(x) 0
  34#endif
  35
  36/*
  37 * Architecture code can redefine this if there are any special checks
  38 * needed for 32-bit ELF or 64-bit ELF vmcores.  In case of 32-bit
  39 * only architecture, vmcore_elf64_check_arch can be set to zero.
  40 */
  41#ifndef vmcore_elf32_check_arch
  42#define vmcore_elf32_check_arch(x) elf_check_arch(x)
  43#endif
  44
  45#ifndef vmcore_elf64_check_arch
  46#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  47#endif
  48
  49/*
  50 * is_kdump_kernel() checks whether this kernel is booting after a panic of
  51 * previous kernel or not. This is determined by checking if previous kernel
  52 * has passed the elf core header address on command line.
  53 *
  54 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  55 * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
  56 * of previous kernel.
  57 */
  58
  59static inline bool is_kdump_kernel(void)
  60{
  61        return elfcorehdr_addr != ELFCORE_ADDR_MAX;
  62}
  63
  64/* is_vmcore_usable() checks if the kernel is booting after a panic and
  65 * the vmcore region is usable.
  66 *
  67 * This makes use of the fact that due to alignment -2ULL is not
  68 * a valid pointer, much in the vain of IS_ERR(), except
  69 * dealing directly with an unsigned long long rather than a pointer.
  70 */
  71
  72static inline int is_vmcore_usable(void)
  73{
  74        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  75}
  76
  77/* vmcore_unusable() marks the vmcore as unusable,
  78 * without disturbing the logic of is_kdump_kernel()
  79 */
  80
  81static inline void vmcore_unusable(void)
  82{
  83        if (is_kdump_kernel())
  84                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  85}
  86
  87#define HAVE_OLDMEM_PFN_IS_RAM 1
  88extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  89extern void unregister_oldmem_pfn_is_ram(void);
  90
  91#else /* !CONFIG_CRASH_DUMP */
  92static inline bool is_kdump_kernel(void) { return 0; }
  93#endif /* CONFIG_CRASH_DUMP */
  94
  95extern unsigned long saved_max_pfn;
  96#endif /* LINUX_CRASHDUMP_H */
  97