[PATCH v1 1/2] zboot: enable arm64 kexec_load for zboot image

[Dave Young]

kexec_file_load support of zboot kernel image decompressed the vmlinuz,
so in kexec_load code just load the kernel with reading the decompressed
kernel fd into a new buffer and use it directly.

Signed-off-by: Dave Young <dyoung at redhat.com>
---
 include/kexec-pe-zboot.h               |  3 ++-
 kexec/arch/arm64/kexec-vmlinuz-arm64.c | 26 +++++++++++++++++++++++---
 kexec/kexec-pe-zboot.c                 |  4 +++-
 kexec/kexec.c                          |  2 +-
 kexec/kexec.h                          |  1 +
 5 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/include/kexec-pe-zboot.h b/include/kexec-pe-zboot.h
index e2e0448a81f2..374916cbe883 100644
--- a/include/kexec-pe-zboot.h
+++ b/include/kexec-pe-zboot.h
@@ -11,5 +11,6 @@ struct linux_pe_zboot_header {
 	uint32_t compress_type;
 };
 
-int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd);
+int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd,
+		off_t *kernel_size);
 #endif
diff --git a/kexec/arch/arm64/kexec-vmlinuz-arm64.c b/kexec/arch/arm64/kexec-vmlinuz-arm64.c
index c0ee47c8f50a..e291a34c97ad 100644
--- a/kexec/arch/arm64/kexec-vmlinuz-arm64.c
+++ b/kexec/arch/arm64/kexec-vmlinuz-arm64.c
@@ -34,6 +34,7 @@
 #include "arch/options.h"
 
 static int kernel_fd = -1;
+static off_t decompressed_size;
 
 /* Returns:
  * -1 : in case of error/invalid format (not a valid PE+compressed ZBOOT format.
@@ -72,7 +73,7 @@ int pez_arm64_probe(const char *kernel_buf, off_t kernel_size)
 		return -1;
 	}
 
-	ret = pez_prepare(buf, buf_sz, &kernel_fd);
+	ret = pez_prepare(buf, buf_sz, &kernel_fd, &decompressed_size);
 
 	if (!ret) {
 	    /* validate the arm64 specific header */
@@ -98,8 +99,27 @@ bad_header:
 int pez_arm64_load(int argc, char **argv, const char *buf, off_t len,
 			struct kexec_info *info)
 {
-	info->kernel_fd = kernel_fd;
-	return image_arm64_load(argc, argv, buf, len, info);
+	if (kernel_fd > 0 && decompressed_size > 0) {
+		char *kbuf;
+		off_t nread;
+		int fd;
+
+		info->kernel_fd = kernel_fd;
+		fd = dup(kernel_fd);
+		if (fd < 0) {
+			dbgprintf("%s: dup fd failed.\n", __func__);
+			return -1;
+		}
+		kbuf = slurp_fd(fd, NULL, decompressed_size, &nread);
+		if (!kbuf || nread != decompressed_size) {
+			dbgprintf("%s: slurp_fd failed.\n", __func__);
+			return -1;
+		}
+		return image_arm64_load(argc, argv, kbuf, decompressed_size, info);
+	}
+
+	dbgprintf("%s: wrong kernel file descriptor.\n", __func__);
+	return -1;
 }
 
 void pez_arm64_usage(void)
diff --git a/kexec/kexec-pe-zboot.c b/kexec/kexec-pe-zboot.c
index 2f2e052b76c5..3abd17d9fe59 100644
--- a/kexec/kexec-pe-zboot.c
+++ b/kexec/kexec-pe-zboot.c
@@ -37,7 +37,8 @@
  *
  * crude_buf: the content, which is read from the kernel file without any processing
  */
-int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd)
+int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd,
+		off_t *kernel_size)
 {
 	int ret = -1;
 	int fd = 0;
@@ -110,6 +111,7 @@ int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd)
 		goto fail_bad_header;
 	}
 
+	*kernel_size = decompressed_size;
 	dbgprintf("%s: done\n", __func__);
 
 	ret = 0;
diff --git a/kexec/kexec.c b/kexec/kexec.c
index c3b182e254e0..1edbd349c86d 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -489,7 +489,7 @@ static int add_backup_segments(struct kexec_info *info,
 	return 0;
 }
 
-static char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread)
+char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread)
 {
 	char *buf;
 	off_t progress;
diff --git a/kexec/kexec.h b/kexec/kexec.h
index ed3b499a80f2..093338969c57 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -267,6 +267,7 @@ extern void die(const char *fmt, ...)
 	__attribute__ ((format (printf, 1, 2)));
 extern void *xmalloc(size_t size);
 extern void *xrealloc(void *ptr, size_t size);
+extern char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread);
 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);
-- 
2.37.2