Currently the kexec_file_load() support for arm64 doesn't allow
handling zlib compressed (i.e. Image.gz) image.

Since most distributions use 'make zinstall' rule inside
'arch/arm64/boot/Makefile' to install the arm64
Image.gz compressed file inside the boot destination directory (for e.g.
/boot), currently we cannot use kexec_file_load() to load vmlinuz (or
Image.gz):

 # file /boot/vmlinuz
   /boot/vmlinuz: gzip compressed data, was "Image", <..snip..>, max
   compression, from Unix, original size 21945120

 Now, since via kexec_file_load() we pass the 'fd' of Image.gz
 (compressed file) via the following command line ...

 # kexec -s -l /boot/vmlinuz-`uname -r` --initrd=/boot/initramfs-`uname
   -r`.img --reuse-cmdline

... kernel returns -EINVAL error value, as it is not able to locate
the magic number =0x644d5241, which is expected in the 64-byte header
of the decompressed kernel image.

We can fix this in user-space kexec-tools, which handles an
'Image.gz' being passed via kexec_file_load(), using an approach
as follows:

a). Copy the contents of Image.gz to a temporary file.
b). Decompress (gunzip-decompress) the contents inside the
    temporary file.
c). Pass the 'fd' of the temporary file to the kernel space. So
    basically the kernel space still gets a decompressed kernel
    image to load via kexec-tools

I tested this patch for the following three use-cases:

1. Uncompressed Image file:
 #kexec -s -l Image --initrd=/boot/initramfs-`uname -r`.img --reuse-cmdline

2. Signed Image file:
 #kexec -s -l Image.signed --initrd=/boot/initramfs-`uname -r`.img 
--reuse-cmdline

3. zlib compressed Image.gz file:
 #kexec -s -l /boot/vmlinuz-`uname -r` --initrd=/boot/initramfs-`uname -r`.img 
--reuse-cmdline

Signed-off-by: Bhupesh Sharma <[email protected]>
---
 kexec/arch/arm64/Makefile             |   3 +-
 kexec/arch/arm64/kexec-arm64.c        |   1 +
 kexec/arch/arm64/kexec-arm64.h        |   7 ++
 kexec/arch/arm64/kexec-image-arm64.c  |   4 +-
 kexec/arch/arm64/kexec-zImage-arm64.c | 199 ++++++++++++++++++++++++++++++++++
 kexec/kexec.c                         |  12 ++
 6 files changed, 223 insertions(+), 3 deletions(-)
 create mode 100644 kexec/arch/arm64/kexec-zImage-arm64.c

diff --git a/kexec/arch/arm64/Makefile b/kexec/arch/arm64/Makefile
index 9d9111caa8ed..d27c8ee1b5e7 100644
--- a/kexec/arch/arm64/Makefile
+++ b/kexec/arch/arm64/Makefile
@@ -15,7 +15,8 @@ arm64_KEXEC_SRCS += \
        kexec/arch/arm64/kexec-arm64.c \
        kexec/arch/arm64/kexec-elf-arm64.c \
        kexec/arch/arm64/kexec-uImage-arm64.c \
-       kexec/arch/arm64/kexec-image-arm64.c
+       kexec/arch/arm64/kexec-image-arm64.c \
+       kexec/arch/arm64/kexec-zImage-arm64.c
 
 arm64_UIMAGE = kexec/kexec-uImage.c
 
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 2992bce8139f..eb3a3a37307c 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -71,6 +71,7 @@ struct file_type file_type[] = {
        {"vmlinux", elf_arm64_probe, elf_arm64_load, elf_arm64_usage},
        {"Image", image_arm64_probe, image_arm64_load, image_arm64_usage},
        {"uImage", uImage_arm64_probe, uImage_arm64_load, uImage_arm64_usage},
+       {"zImage", zImage_arm64_probe, zImage_arm64_load, zImage_arm64_usage},
 };
 
 int file_types = sizeof(file_type) / sizeof(file_type[0]);
diff --git a/kexec/arch/arm64/kexec-arm64.h b/kexec/arch/arm64/kexec-arm64.h
index cc3419f4c10f..628de79b7f70 100644
--- a/kexec/arch/arm64/kexec-arm64.h
+++ b/kexec/arch/arm64/kexec-arm64.h
@@ -38,11 +38,18 @@ int image_arm64_probe(const char *kernel_buf, off_t 
kernel_size);
 int image_arm64_load(int argc, char **argv, const char *kernel_buf,
        off_t kernel_size, struct kexec_info *info);
 void image_arm64_usage(void);
+
 int uImage_arm64_probe(const char *buf, off_t len);
 int uImage_arm64_load(int argc, char **argv, const char *buf, off_t len,
                      struct kexec_info *info);
 void uImage_arm64_usage(void);
 
+int zImage_arm64_probe(const char *kernel_buf, off_t kernel_size);
+int zImage_arm64_load(int argc, char **argv, const char *kernel_buf,
+       off_t kernel_size, struct kexec_info *info);
+void zImage_arm64_usage(void);
+
+
 off_t initrd_base;
 off_t initrd_size;
 
diff --git a/kexec/arch/arm64/kexec-image-arm64.c 
b/kexec/arch/arm64/kexec-image-arm64.c
index 685a99352e39..aa8f2e22d72b 100644
--- a/kexec/arch/arm64/kexec-image-arm64.c
+++ b/kexec/arch/arm64/kexec-image-arm64.c
@@ -114,6 +114,6 @@ exit:
 void image_arm64_usage(void)
 {
        printf(
-"     An ARM64 binary image, compressed or not, big or little endian.\n"
-"     Typically an Image, Image.gz or Image.lzma file.\n\n");
+"     An ARM64 binary image, uncompressed, big or little endian.\n"
+"     Typically an Image file.\n\n");
 }
diff --git a/kexec/arch/arm64/kexec-zImage-arm64.c 
b/kexec/arch/arm64/kexec-zImage-arm64.c
new file mode 100644
index 000000000000..2b83ef6bdffd
--- /dev/null
+++ b/kexec/arch/arm64/kexec-zImage-arm64.c
@@ -0,0 +1,199 @@
+/*
+ * ARM64 kexec zImage (Image.gz) support.
+ *
+ * Several distros use 'make zinstall' rule inside
+ * 'arch/arm64/boot/Makefile' to install the arm64
+ * Image.gz compressed file inside the boot destination
+ * directory (for e.g. /boot).
+ *
+ * Currently we cannot use kexec_file_load() to load vmlinuz
+ * (or Image.gz).
+ *
+ * To support Image.gz, we should:
+ * a). Copy the contents of Image.gz to a temporary file.
+ * b). Decompress (gunzip-decompress) the contents inside the
+ *     temporary file.
+ * c). Pass the 'fd' of the temporary file to the kernel space.
+ *
+ * So basically the kernel space still gets a decompressed
+ * kernel image to load via kexec-tools.
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdlib.h>
+#include "crashdump-arm64.h"
+#include "image-header.h"
+#include "kexec.h"
+#include "kexec-arm64.h"
+#include "kexec-syscall.h"
+#include "kexec-zlib.h"
+#include "arch/options.h"
+
+#define FILENAME_IMAGE         "/tmp/ImageXXXXXX"
+
+/* Returns:
+ * -1 : in case of error/invalid format (not a valid Image.gz format.
+ *  fd: File descriptor of the temp file containing the decompressed
+ *      Image.
+ */
+int zImage_arm64_probe(const char *kernel_buf, off_t kernel_size)
+{
+       int kernel_fd = 0;
+       char *fname = NULL;
+       char *kernel_uncompressed_buf = NULL;
+       const struct arm64_image_header *h;
+
+       if (!is_zlib_file(kernel_buf, &kernel_size)) {
+               dbgprintf("%s: Not an zImage file (Image.gz).\n", __func__);
+               return -1;
+       }
+
+       if (!(fname = strdup(FILENAME_IMAGE))) {
+               dbgprintf("%s: Can't duplicate strings %s\n", __func__,
+                               fname);
+               return -1;
+       }
+
+       if ((kernel_fd = mkstemp(fname)) < 0) {
+               dbgprintf("%s: Can't open file %s\n", __func__,
+                               fname);
+               return -1;
+       }
+
+       kernel_uncompressed_buf =
+               (char *) calloc(kernel_size, sizeof(off_t));
+       if (!kernel_uncompressed_buf) {
+               dbgprintf("%s: Can't calloc %ld bytes\n",
+                               __func__, kernel_size);
+               return -ENOMEM;
+       }
+
+       /* slurp in the input kernel */
+       dbgprintf("%s: ", __func__);
+       kernel_uncompressed_buf = slurp_decompress_file(kernel_buf,
+                                                       &kernel_size);
+
+       /* check for correct header magic */
+       if (kernel_size < sizeof(struct arm64_image_header)) {
+               dbgprintf("%s: No arm64 image header.\n", __func__);
+               return -1;
+       }
+
+       h = (const struct arm64_image_header *)(kernel_uncompressed_buf);
+
+       if (!arm64_header_check_magic(h)) {
+               dbgprintf("%s: Bad arm64 image header.\n", __func__);
+               return -1;
+       }
+
+       if (write(kernel_fd, kernel_uncompressed_buf,
+                               kernel_size) != kernel_size) {
+               dbgprintf("%s: Can't write the uncompressed file %s\n",
+                               __func__, fname);
+               return -1;
+       }
+
+       close(kernel_fd);
+
+       /* Open the tmp file again, this time in O_RDONLY mode, as
+        * opening the file in O_RDWR and calling kexec_file_load()
+        * causes the kernel to return -ETXTBSY
+        */
+       kernel_fd = open(fname, O_RDONLY);
+       if (kernel_fd == -1) {
+               dbgprintf("%s: Failed to open file %s\n",
+                               __func__, fname);
+               return -1;
+       }
+
+       return kernel_fd;
+}
+
+int zImage_arm64_load(int argc, char **argv, const char *kernel_buf,
+       off_t kernel_size, struct kexec_info *info)
+{
+       const struct arm64_image_header *header;
+       unsigned long kernel_segment;
+       int result;
+
+       if (info->file_mode) {
+               if (arm64_opts.initrd) {
+                       info->initrd_fd = open(arm64_opts.initrd, O_RDONLY);
+                       if (info->initrd_fd == -1) {
+                               fprintf(stderr,
+                                       "Could not open initrd file %s:%s\n",
+                                       arm64_opts.initrd, strerror(errno));
+                               result = EFAILED;
+                               goto exit;
+                       }
+               }
+
+               if (arm64_opts.command_line) {
+                       info->command_line = (char *)arm64_opts.command_line;
+                       info->command_line_len =
+                                       strlen(arm64_opts.command_line) + 1;
+               }
+
+               return 0;
+       }
+
+       header = (const struct arm64_image_header *)(kernel_buf);
+
+       if (arm64_process_image_header(header))
+               return EFAILED;
+
+       kernel_segment = arm64_locate_kernel_segment(info);
+
+       if (kernel_segment == ULONG_MAX) {
+               dbgprintf("%s: Kernel segment is not allocated\n", __func__);
+               result = EFAILED;
+               goto exit;
+       }
+
+       dbgprintf("%s: kernel_segment: %016lx\n", __func__, kernel_segment);
+       dbgprintf("%s: text_offset:    %016lx\n", __func__,
+               arm64_mem.text_offset);
+       dbgprintf("%s: image_size:     %016lx\n", __func__,
+               arm64_mem.image_size);
+       dbgprintf("%s: phys_offset:    %016lx\n", __func__,
+               arm64_mem.phys_offset);
+       dbgprintf("%s: vp_offset:      %016lx\n", __func__,
+               arm64_mem.vp_offset);
+       dbgprintf("%s: PE format:      %s\n", __func__,
+               (arm64_header_check_pe_sig(header) ? "yes" : "no"));
+
+       /* create and initialize elf core header segment */
+       if (info->kexec_flags & KEXEC_ON_CRASH) {
+               result = load_crashdump_segments(info);
+               if (result) {
+                       dbgprintf("%s: Creating eflcorehdr failed.\n",
+                                                               __func__);
+                       goto exit;
+               }
+       }
+
+       /* load the kernel */
+       add_segment_phys_virt(info, kernel_buf, kernel_size,
+                       kernel_segment + arm64_mem.text_offset,
+                       arm64_mem.image_size, 0);
+
+       /* load additional data */
+       result = arm64_load_other_segments(info, kernel_segment
+               + arm64_mem.text_offset);
+
+exit:
+       if (result)
+               fprintf(stderr, "kexec: load failed.\n");
+       return result;
+}
+
+void zImage_arm64_usage(void)
+{
+       printf(
+"     An ARM64 zImage, compressed, big or little endian.\n"
+"     Typically an Image.gz or Image.lzma file.\n\n");
+}
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 8ca3b457cac8..bc6ab3dbd10b 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -1206,8 +1206,20 @@ static int do_kexec_file_load(int fileind, int argc, 
char **argv,
        kernel_buf = slurp_decompress_file(kernel, &kernel_size);
 
        for (i = 0; i < file_types; i++) {
+#ifdef __aarch64__
+               /* handle Image.gz like cases */
+               if (is_zlib_file(kernel, &kernel_size)) {
+                       if ((ret = file_type[i].probe(kernel, kernel_size)) >= 
0) {
+                               kernel_fd = ret;
+                               break;
+                       }
+               } else
+                       if (file_type[i].probe(kernel_buf, kernel_size) >= 0)
+                               break;
+#else
                if (file_type[i].probe(kernel_buf, kernel_size) >= 0)
                        break;
+#endif
        }
 
        if (i == file_types) {
-- 
2.7.4


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