1 files changed, 100 insertions, 0 deletions
diff --git a/tools/testing/selftests/kho/init.c b/tools/testing/selftests/kho/init.c
new file mode 100644
index 000000000000..8034e24c6bf6
--- /dev/null
+++ b/tools/testing/selftests/kho/init.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef NOLIBC
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <syscall.h>
+#include <sys/mount.h>
+#include <sys/reboot.h>
+#endif
+
+/* from arch/x86/include/asm/setup.h */
+#define COMMAND_LINE_SIZE	2048
+
+/* from include/linux/kexex.h */
+#define KEXEC_FILE_NO_INITRAMFS	0x00000004
+
+#define KHO_FINILIZE "/debugfs/kho/out/finalize"
+#define KERNEL_IMAGE "/kernel"
+
+static int mount_filesystems(void)
+{
+	if (mount("debugfs", "/debugfs", "debugfs", 0, NULL) < 0)
+		return -1;
+
+	return mount("proc", "/proc", "proc", 0, NULL);
+}
+
+static int kho_enable(void)
+{
+	const char enable[] = "1";
+	int fd;
+
+	fd = open(KHO_FINILIZE, O_RDWR);
+	if (fd < 0)
+		return -1;
+
+	if (write(fd, enable, sizeof(enable)) != sizeof(enable))
+		return 1;
+
+	close(fd);
+	return 0;
+}
+
+static long kexec_file_load(int kernel_fd, int initrd_fd,
+			    unsigned long cmdline_len, const char *cmdline,
+			    unsigned long flags)
+{
+	return syscall(__NR_kexec_file_load, kernel_fd, initrd_fd, cmdline_len,
+		       cmdline, flags);
+}
+
+static int kexec_load(void)
+{
+	char cmdline[COMMAND_LINE_SIZE];
+	ssize_t len;
+	int fd, err;
+
+	fd = open("/proc/cmdline", O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	len = read(fd, cmdline, sizeof(cmdline));
+	close(fd);
+	if (len < 0)
+		return -1;
+
+	/* replace \n with \0 */
+	cmdline[len - 1] = 0;
+	fd = open(KERNEL_IMAGE, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	err = kexec_file_load(fd, -1, len, cmdline, KEXEC_FILE_NO_INITRAMFS);
+	close(fd);
+
+	return err ? : 0;
+}
+
+int main(int argc, char *argv[])
+{
+	if (mount_filesystems())
+		goto err_reboot;
+
+	if (kho_enable())
+		goto err_reboot;
+
+	if (kexec_load())
+		goto err_reboot;
+
+	if (reboot(RB_KEXEC))
+		goto err_reboot;
+
+	return 0;
+
+err_reboot:
+	reboot(RB_AUTOBOOT);
+	return -1;
+}