include/linux/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
   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
  15 extern unsigned long long elfcorehdr_addr;
  16 extern unsigned long long elfcorehdr_size;
  17
  18 extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
  19 extern void elfcorehdr_free(unsigned long long addr);
  20 extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
  21 extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
  22 extern 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
  26 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  27                                                 unsigned long, int);
  28 void 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
  59 static 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
  72 static 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
  81 static 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
  88 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  89 extern void unregister_oldmem_pfn_is_ram(void);
  90
  91 #else /* !CONFIG_CRASH_DUMP */
  92 static inline bool is_kdump_kernel(void) { return 0; }
  93 #endif /* CONFIG_CRASH_DUMP */
  94
  95 extern unsigned long saved_max_pfn;
  96 #endif /* LINUX_CRASHDUMP_H */