3 files changed, 30 insertions, 4 deletions
diff --git a/kexec/arch/s390/kexec-image.c b/kexec/arch/s390/kexec-image.c
index be1e0f8..0c8937b 100644
--- a/kexec/arch/s390/kexec-image.c
+++ b/kexec/arch/s390/kexec-image.c
@@ -101,7 +101,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
 	 * we load the ramdisk directly behind the image with 1 MiB alignment.
 	 */
 	if (ramdisk) {
-		rd_buffer = slurp_file(ramdisk, &ramdisk_len);
+		rd_buffer = slurp_file_mmap(ramdisk, &ramdisk_len);
 		if (rd_buffer == NULL) {
 			fprintf(stderr, "Could not read ramdisk.\n");
 			return -1;
diff --git a/kexec/kexec.c b/kexec/kexec.c
index b9f1816..ca1e81d 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -29,6 +29,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/reboot.h>
+#include <sys/mman.h>
 #include <unistd.h>
 #include <fcntl.h>
 #ifndef _O_BINARY
@@ -514,7 +515,8 @@ static char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread)
 	return buf;
 }
 
-char *slurp_file(const char *filename, off_t *r_size)
+static char *slurp_file_generic(const char *filename, off_t *r_size,
+				int use_mmap)
 {
 	int fd;
 	char *buf;
@@ -552,11 +554,17 @@ char *slurp_file(const char *filename, off_t *r_size)
 		if (err < 0)
 			die("Can not seek to the begin of file %s: %s\n",
 					filename, strerror(errno));
+		buf = slurp_fd(fd, filename, size, &nread);
 	} else {
 		size = stats.st_size;
+		if (use_mmap) {
+			buf = mmap(NULL, size, PROT_READ|PROT_WRITE,
+				   MAP_PRIVATE, fd, 0);
+			nread = size;
+		} else {
+			buf = slurp_fd(fd, filename, size, &nread);
+		}
 	}
-
-	buf = slurp_fd(fd, filename, size, &nread);
 	if (!buf)
 		die("Cannot read %s", filename);
 
@@ -567,6 +575,23 @@ char *slurp_file(const char *filename, off_t *r_size)
 	return buf;
 }
 
+/*
+ * Read file into malloced buffer.
+ */
+char *slurp_file(const char *filename, off_t *r_size)
+{
+	return slurp_file_generic(filename, r_size, 0);
+}
+
+/*
+ * Map "normal" file or read "character device" into malloced buffer.
+ * You must not use free, realloc, etc. for the returned buffer.
+ */
+char *slurp_file_mmap(const char *filename, off_t *r_size)
+{
+	return slurp_file_generic(filename, r_size, 1);
+}
+
 /* This functions reads either specified number of bytes from the file or
    lesser if EOF is met. */
 
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 7c97b25..c02ac8f 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -253,6 +253,7 @@ extern void die(const char *fmt, ...)
 extern void *xmalloc(size_t size);
 extern void *xrealloc(void *ptr, size_t size);
 extern char *slurp_file(const char *filename, off_t *r_size);
+extern char *slurp_file_mmap(const char *filename, off_t *r_size);
 extern char *slurp_file_len(const char *filename, off_t size, off_t *nread);
 extern char *slurp_decompress_file(const char *filename, off_t *r_size);
 extern unsigned long virt_to_phys(unsigned long addr);