test_kexec_jump.c

 1#include <unistd.h>
 2#include <errno.h>
 3#include <stdio.h>
 4#include <stdlib.h>
 5#include <linux/kexec.h>
 6#include <linux/reboot.h>
 7#include <sys/reboot.h>
 8#include <sys/syscall.h>
 9
10asm(
11    "  .code64\n"
12    "  .data\n"
13    "purgatory_start:\n"
14
15    // Trigger kexec debug exception handling
16    "  int3\n"
17
18    // Set load address for next time
19    "  leaq purgatory_start_b(%rip), %r11\n"
20    "  movq %r11, 8(%rsp)\n"
21
22    // Back to Linux
23    "  ret\n"
24
25    // Same again
26    "purgatory_start_b:\n"
27
28    // Trigger kexec debug exception handling
29    "  int3\n"
30
31    // Set load address for next time
32    "  leaq purgatory_start(%rip), %r11\n"
33    "  movq %r11, 8(%rsp)\n"
34
35    // Back to Linux
36    "  ret\n"
37
38    "purgatory_end:\n"
39    ".previous"
40);
41extern char purgatory_start[], purgatory_end[];
42
43int main (void)
44{
45        struct kexec_segment segment = {};
46	int ret;
47
48	segment.buf = purgatory_start;
49	segment.bufsz = purgatory_end - purgatory_start;
50	segment.mem = (void *)0x400000;
51	segment.memsz = 0x1000;
52	ret = syscall(__NR_kexec_load, 0x400000, 1, &segment, KEXEC_PRESERVE_CONTEXT);
53	if (ret) {
54		perror("kexec_load");
55		exit(1);
56	}
57
58	ret = syscall(__NR_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_KEXEC);
59	if (ret) {
60		perror("kexec reboot");
61		exit(1);
62	}
63
64	ret = syscall(__NR_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_KEXEC);
65	if (ret) {
66		perror("kexec reboot");
67		exit(1);
68	}
69	printf("Success\n");
70	return 0;
71}
72