Linux kernel 笔记 （14）——is_kdump_kernel函数

#ifdef CONFIG_CRASH_DUMP
/*
 * is_kdump_kernel() checks whether this kernel is booting after a panic of
 * previous kernel or not. This is determined by checking if previous kernel
 * has passed the elf core header address on command line.
 *
 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
 * previous kernel.
 */

static inline int is_kdump_kernel(void)
{
    return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
}
#else /* !CONFIG_CRASH_DUMP */
static inline int is_kdump_kernel(void) { return 0; }
#endif /* CONFIG_CRASH_DUMP */

is_kdump_kernel用来检查当前运行的kernel是不是由于之前运行的kernel panic了，而重启的kernel。如果没有配置CONFIG_CRASH_DUMP，则总是返回0。