include/linux/crash_dump.h

   1 #ifndef LINUX_CRASH_DUMP_H
   2 #define LINUX_CRASH_DUMP_H
   3
   4 #ifdef CONFIG_CRASH_DUMP
   5 #include <linux/kexec.h>
   6 #include <linux/proc_fs.h>
   7 #include <linux/elf.h>
   8
   9 #define ELFCORE_ADDR_MAX        (-1ULL)
  10 #define ELFCORE_ADDR_ERR        (-2ULL)
  11
  12 extern unsigned long long elfcorehdr_addr;
  13 extern unsigned long long elfcorehdr_size;
  14
  15 extern int __weak elfcorehdr_alloc(unsigned long long *addr,
  16                                    unsigned long long *size);
  17 extern void __weak elfcorehdr_free(unsigned long long addr);
  18 extern ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos);
  19 extern ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
  20 extern int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
  21                                          unsigned long from, unsigned long pfn,
  22                                          unsigned long size, pgprot_t prot);
  23
  24 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  25                                                 unsigned long, int);
  26
  27 /* Architecture code defines this if there are other possible ELF
  28  * machine types, e.g. on bi-arch capable hardware. */
  29 #ifndef vmcore_elf_check_arch_cross
  30 #define vmcore_elf_check_arch_cross(x) 0
  31 #endif
  32
  33 /*
  34  * Architecture code can redefine this if there are any special checks
  35  * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
  36  * this can be set to zero.
  37  */
  38 #ifndef vmcore_elf64_check_arch
  39 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  40 #endif
  41
  42 /*
  43  * is_kdump_kernel() checks whether this kernel is booting after a panic of
  44  * previous kernel or not. This is determined by checking if previous kernel
  45  * has passed the elf core header address on command line.
  46  *
  47  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  48  * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  49  * previous kernel.
  50  */
  51
  52 static inline int is_kdump_kernel(void)
  53 {
  54         return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  55 }
  56
  57 /* is_vmcore_usable() checks if the kernel is booting after a panic and
  58  * the vmcore region is usable.
  59  *
  60  * This makes use of the fact that due to alignment -2ULL is not
  61  * a valid pointer, much in the vain of IS_ERR(), except
  62  * dealing directly with an unsigned long long rather than a pointer.
  63  */
  64
  65 static inline int is_vmcore_usable(void)
  66 {
  67         return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  68 }
  69
  70 /* vmcore_unusable() marks the vmcore as unusable,
  71  * without disturbing the logic of is_kdump_kernel()
  72  */
  73
  74 static inline void vmcore_unusable(void)
  75 {
  76         if (is_kdump_kernel())
  77                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  78 }
  79
  80 #define HAVE_OLDMEM_PFN_IS_RAM 1
  81 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  82 extern void unregister_oldmem_pfn_is_ram(void);
  83
  84 #else /* !CONFIG_CRASH_DUMP */
  85 static inline int is_kdump_kernel(void) { return 0; }
  86 #endif /* CONFIG_CRASH_DUMP */
  87
  88 extern unsigned long saved_max_pfn;
  89 #endif /* LINUX_CRASHDUMP_H */