s390/kexec_file: Add image loader

Add an image loader for kexec_file_load. For simplicity first skip crash
support. The functions defined in machine_kexec_file will later be shared
with the ELF loader.

Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com>
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/arch/s390/kernel/kexec_image.c b/arch/s390/kernel/kexec_image.c
new file mode 100644
index 000000000000..7f5021e6c242
--- /dev/null
+++ b/arch/s390/kernel/kexec_image.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Image loader for kexec_file_load system call.
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <asm/setup.h>
+
+static int kexec_file_add_image_kernel(struct kimage *image,
+				       struct s390_load_data *data,
+				       char *kernel, unsigned long kernel_len)
+{
+	struct kexec_buf buf;
+	int ret;
+
+	buf.image = image;
+
+	buf.buffer = kernel + STARTUP_NORMAL_OFFSET;
+	buf.bufsz = kernel_len - STARTUP_NORMAL_OFFSET;
+
+	buf.mem = STARTUP_NORMAL_OFFSET;
+	buf.memsz = buf.bufsz;
+
+	ret = kexec_add_buffer(&buf);
+
+	data->kernel_buf = kernel;
+	data->memsz += buf.memsz + STARTUP_NORMAL_OFFSET;
+
+	return ret;
+}
+
+static void *s390_image_load(struct kimage *image,
+			     char *kernel, unsigned long kernel_len,
+			     char *initrd, unsigned long initrd_len,
+			     char *cmdline, unsigned long cmdline_len)
+{
+	struct s390_load_data data = {0};
+	int ret;
+
+	/* We don't support crash kernels yet. */
+	if (image->type == KEXEC_TYPE_CRASH)
+		return ERR_PTR(-ENOTSUPP);
+
+	ret = kexec_file_add_image_kernel(image, &data, kernel, kernel_len);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (initrd) {
+		ret = kexec_file_add_initrd(image, &data, initrd, initrd_len);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	ret = kexec_file_add_purgatory(image, &data);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return kexec_file_update_kernel(image, &data);
+}
+
+static int s390_image_probe(const char *buf, unsigned long len)
+{
+	/* Can't reliably tell if an image is valid.  Therefore give the
+	 * user whatever he wants.
+	 */
+	return 0;
+}
+
+const struct kexec_file_ops s390_kexec_image_ops = {
+	.probe = s390_image_probe,
+	.load = s390_image_load,
+};