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