1*b753522bSMike Rapoport (Microsoft) // SPDX-License-Identifier: GPL-2.0
2*b753522bSMike Rapoport (Microsoft)
3*b753522bSMike Rapoport (Microsoft) #ifndef NOLIBC
4*b753522bSMike Rapoport (Microsoft) #include <errno.h>
5*b753522bSMike Rapoport (Microsoft) #include <stdio.h>
6*b753522bSMike Rapoport (Microsoft) #include <unistd.h>
7*b753522bSMike Rapoport (Microsoft) #include <fcntl.h>
8*b753522bSMike Rapoport (Microsoft) #include <syscall.h>
9*b753522bSMike Rapoport (Microsoft) #include <sys/mount.h>
10*b753522bSMike Rapoport (Microsoft) #include <sys/reboot.h>
11*b753522bSMike Rapoport (Microsoft) #endif
12*b753522bSMike Rapoport (Microsoft)
13*b753522bSMike Rapoport (Microsoft) /* from arch/x86/include/asm/setup.h */
14*b753522bSMike Rapoport (Microsoft) #define COMMAND_LINE_SIZE 2048
15*b753522bSMike Rapoport (Microsoft)
16*b753522bSMike Rapoport (Microsoft) /* from include/linux/kexex.h */
17*b753522bSMike Rapoport (Microsoft) #define KEXEC_FILE_NO_INITRAMFS 0x00000004
18*b753522bSMike Rapoport (Microsoft)
19*b753522bSMike Rapoport (Microsoft) #define KHO_FINILIZE "/debugfs/kho/out/finalize"
20*b753522bSMike Rapoport (Microsoft) #define KERNEL_IMAGE "/kernel"
21*b753522bSMike Rapoport (Microsoft)
mount_filesystems(void)22*b753522bSMike Rapoport (Microsoft) static int mount_filesystems(void)
23*b753522bSMike Rapoport (Microsoft) {
24*b753522bSMike Rapoport (Microsoft) if (mount("debugfs", "/debugfs", "debugfs", 0, NULL) < 0)
25*b753522bSMike Rapoport (Microsoft) return -1;
26*b753522bSMike Rapoport (Microsoft)
27*b753522bSMike Rapoport (Microsoft) return mount("proc", "/proc", "proc", 0, NULL);
28*b753522bSMike Rapoport (Microsoft) }
29*b753522bSMike Rapoport (Microsoft)
kho_enable(void)30*b753522bSMike Rapoport (Microsoft) static int kho_enable(void)
31*b753522bSMike Rapoport (Microsoft) {
32*b753522bSMike Rapoport (Microsoft) const char enable[] = "1";
33*b753522bSMike Rapoport (Microsoft) int fd;
34*b753522bSMike Rapoport (Microsoft)
35*b753522bSMike Rapoport (Microsoft) fd = open(KHO_FINILIZE, O_RDWR);
36*b753522bSMike Rapoport (Microsoft) if (fd < 0)
37*b753522bSMike Rapoport (Microsoft) return -1;
38*b753522bSMike Rapoport (Microsoft)
39*b753522bSMike Rapoport (Microsoft) if (write(fd, enable, sizeof(enable)) != sizeof(enable))
40*b753522bSMike Rapoport (Microsoft) return 1;
41*b753522bSMike Rapoport (Microsoft)
42*b753522bSMike Rapoport (Microsoft) close(fd);
43*b753522bSMike Rapoport (Microsoft) return 0;
44*b753522bSMike Rapoport (Microsoft) }
45*b753522bSMike Rapoport (Microsoft)
kexec_file_load(int kernel_fd,int initrd_fd,unsigned long cmdline_len,const char * cmdline,unsigned long flags)46*b753522bSMike Rapoport (Microsoft) static long kexec_file_load(int kernel_fd, int initrd_fd,
47*b753522bSMike Rapoport (Microsoft) unsigned long cmdline_len, const char *cmdline,
48*b753522bSMike Rapoport (Microsoft) unsigned long flags)
49*b753522bSMike Rapoport (Microsoft) {
50*b753522bSMike Rapoport (Microsoft) return syscall(__NR_kexec_file_load, kernel_fd, initrd_fd, cmdline_len,
51*b753522bSMike Rapoport (Microsoft) cmdline, flags);
52*b753522bSMike Rapoport (Microsoft) }
53*b753522bSMike Rapoport (Microsoft)
kexec_load(void)54*b753522bSMike Rapoport (Microsoft) static int kexec_load(void)
55*b753522bSMike Rapoport (Microsoft) {
56*b753522bSMike Rapoport (Microsoft) char cmdline[COMMAND_LINE_SIZE];
57*b753522bSMike Rapoport (Microsoft) ssize_t len;
58*b753522bSMike Rapoport (Microsoft) int fd, err;
59*b753522bSMike Rapoport (Microsoft)
60*b753522bSMike Rapoport (Microsoft) fd = open("/proc/cmdline", O_RDONLY);
61*b753522bSMike Rapoport (Microsoft) if (fd < 0)
62*b753522bSMike Rapoport (Microsoft) return -1;
63*b753522bSMike Rapoport (Microsoft)
64*b753522bSMike Rapoport (Microsoft) len = read(fd, cmdline, sizeof(cmdline));
65*b753522bSMike Rapoport (Microsoft) close(fd);
66*b753522bSMike Rapoport (Microsoft) if (len < 0)
67*b753522bSMike Rapoport (Microsoft) return -1;
68*b753522bSMike Rapoport (Microsoft)
69*b753522bSMike Rapoport (Microsoft) /* replace \n with \0 */
70*b753522bSMike Rapoport (Microsoft) cmdline[len - 1] = 0;
71*b753522bSMike Rapoport (Microsoft) fd = open(KERNEL_IMAGE, O_RDONLY);
72*b753522bSMike Rapoport (Microsoft) if (fd < 0)
73*b753522bSMike Rapoport (Microsoft) return -1;
74*b753522bSMike Rapoport (Microsoft)
75*b753522bSMike Rapoport (Microsoft) err = kexec_file_load(fd, -1, len, cmdline, KEXEC_FILE_NO_INITRAMFS);
76*b753522bSMike Rapoport (Microsoft) close(fd);
77*b753522bSMike Rapoport (Microsoft)
78*b753522bSMike Rapoport (Microsoft) return err ? : 0;
79*b753522bSMike Rapoport (Microsoft) }
80*b753522bSMike Rapoport (Microsoft)
main(int argc,char * argv[])81*b753522bSMike Rapoport (Microsoft) int main(int argc, char *argv[])
82*b753522bSMike Rapoport (Microsoft) {
83*b753522bSMike Rapoport (Microsoft) if (mount_filesystems())
84*b753522bSMike Rapoport (Microsoft) goto err_reboot;
85*b753522bSMike Rapoport (Microsoft)
86*b753522bSMike Rapoport (Microsoft) if (kho_enable())
87*b753522bSMike Rapoport (Microsoft) goto err_reboot;
88*b753522bSMike Rapoport (Microsoft)
89*b753522bSMike Rapoport (Microsoft) if (kexec_load())
90*b753522bSMike Rapoport (Microsoft) goto err_reboot;
91*b753522bSMike Rapoport (Microsoft)
92*b753522bSMike Rapoport (Microsoft) if (reboot(RB_KEXEC))
93*b753522bSMike Rapoport (Microsoft) goto err_reboot;
94*b753522bSMike Rapoport (Microsoft)
95*b753522bSMike Rapoport (Microsoft) return 0;
96*b753522bSMike Rapoport (Microsoft)
97*b753522bSMike Rapoport (Microsoft) err_reboot:
98*b753522bSMike Rapoport (Microsoft) reboot(RB_AUTOBOOT);
99*b753522bSMike Rapoport (Microsoft) return -1;
100*b753522bSMike Rapoport (Microsoft) }
101