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/device.h> 7 #include <linux/proc_fs.h> 8 9 #define ELFCORE_ADDR_MAX (-1ULL) 10 #define ELFCORE_ADDR_ERR (-2ULL) 11 12 extern unsigned long long elfcorehdr_addr; 13 14 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, 15 unsigned long, int); 16 17 /* Architecture code defines this if there are other possible ELF 18 * machine types, e.g. on bi-arch capable hardware. */ 19 #ifndef vmcore_elf_check_arch_cross 20 #define vmcore_elf_check_arch_cross(x) 0 21 #endif 22 23 #define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) 24 25 /* 26 * is_kdump_kernel() checks whether this kernel is booting after a panic of 27 * previous kernel or not. This is determined by checking if previous kernel 28 * has passed the elf core header address on command line. 29 * 30 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will 31 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of 32 * previous kernel. 33 */ 34 35 static inline int is_kdump_kernel(void) 36 { 37 return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0; 38 } 39 40 /* is_vmcore_usable() checks if the kernel is booting after a panic and 41 * the vmcore region is usable. 42 * 43 * This makes use of the fact that due to alignment -2ULL is not 44 * a valid pointer, much in the vain of IS_ERR(), except 45 * dealing directly with an unsigned long long rather than a pointer. 46 */ 47 48 static inline int is_vmcore_usable(void) 49 { 50 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; 51 } 52 53 /* vmcore_unusable() marks the vmcore as unusable, 54 * without disturbing the logic of is_kdump_kernel() 55 */ 56 57 static inline void vmcore_unusable(void) 58 { 59 if (is_kdump_kernel()) 60 elfcorehdr_addr = ELFCORE_ADDR_ERR; 61 } 62 #else /* !CONFIG_CRASH_DUMP */ 63 static inline int is_kdump_kernel(void) { return 0; } 64 #endif /* CONFIG_CRASH_DUMP */ 65 66 extern unsigned long saved_max_pfn; 67 #endif /* LINUX_CRASHDUMP_H */ 68