Hi Pingfan, Simon,
On 07/17/23 at 09:07pm, Pingfan Liu wrote:
> As more complicated capsule kernel format occurs like zboot, where the
> compressed kernel is stored as a payload. The straight forward
> decompression can not meet the demand.
>
> As the first step, on aarch64, reading in the kernel file in a probe
> method and decide how to unfold the content by the method itself.
>
> This series introduce a new image probe interface probe2(), which
> returns three factors: kernel buffer, kernel size and kernel fd through
> a struct parsed_info.
> -1. the parsed kernel_buf should be returned so that it can be used by
> the image load method later.
> -2. the final fd passed to sys_kexec_file_load, since aarch64 kernel can
> only work with Image format, the outer payload should be stripped and a
> temporary file of Image should be created.
I took a look at the Image.gz file load code, the current code can be
simplified with passing a fd directly instead of creating temp files via
memfd_create with the already decompressed kernel_buf.
The current file load is like below:
do_kexec_file_load():
1.slurp_decompress_file
2. probe
3. load
4. kexec_file_load
In step 1, the Image.gz has been decompressed to kernel_buf, so just
create a virtual memfd copy to it, then save the virtual fd for step 4
use.
Otherwise in step 2 it is some sanity checking, step 3 is setting
something else eg. initrd_fd, cmdline. With the changes below Image and
Image.gz will share same code. I think you can add the zboot
detection/checking code in the Image probe, load functions, with a new
info->kernel_fd, you can decompress the zboot kernel_buf and save to
another virtual memfd, and set to the info->kernel_fd. Then in step 4
the kexec_file_load can just use it.
The kernel_buf itself is only used for sanity checking of the formats,
kernel only needs a file fd, so I think it should be fine and easier
than the original ways.
Thoughts?
---
kexec/arch/arm64/Makefile | 3
kexec/arch/arm64/kexec-arm64.c | 1
kexec/arch/arm64/kexec-arm64.h | 6
kexec/arch/arm64/kexec-image-arm64.c | 2
kexec/arch/arm64/kexec-zImage-arm64.c | 226 ----------------------------------
kexec/kexec.c | 55 +++++---
kexec/kexec.h | 1
7 files changed, 39 insertions(+), 255 deletions(-)
Index: kexec-tools/kexec/arch/arm64/Makefile
===================================================================
--- kexec-tools.orig/kexec/arch/arm64/Makefile
+++ kexec-tools/kexec/arch/arm64/Makefile
@@ -15,8 +15,7 @@ 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-zImage-arm64.c
+ kexec/arch/arm64/kexec-image-arm64.c
arm64_UIMAGE = kexec/kexec-uImage.c
Index: kexec-tools/kexec/arch/arm64/kexec-arm64.c
===================================================================
--- kexec-tools.orig/kexec/arch/arm64/kexec-arm64.c
+++ kexec-tools/kexec/arch/arm64/kexec-arm64.c
@@ -74,7 +74,6 @@ 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]);
Index: kexec-tools/kexec/arch/arm64/kexec-arm64.h
===================================================================
--- kexec-tools.orig/kexec/arch/arm64/kexec-arm64.h
+++ kexec-tools/kexec/arch/arm64/kexec-arm64.h
@@ -44,12 +44,6 @@ int uImage_arm64_load(int argc, char **a
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);
-
-
extern off_t initrd_base;
extern off_t initrd_size;
Index: kexec-tools/kexec/arch/arm64/kexec-image-arm64.c
===================================================================
--- kexec-tools.orig/kexec/arch/arm64/kexec-image-arm64.c
+++ kexec-tools/kexec/arch/arm64/kexec-image-arm64.c
@@ -114,6 +114,6 @@ exit:
void image_arm64_usage(void)
{
printf(
-" An ARM64 binary image, uncompressed, big or little endian.\n"
+" An ARM64 binary image, compressed or not, big or little endian.\n"
" Typically an Image file.\n\n");
}
Index: kexec-tools/kexec/arch/arm64/kexec-zImage-arm64.c
===================================================================
--- kexec-tools.orig/kexec/arch/arm64/kexec-zImage-arm64.c
+++ /dev/null
@@ -1,226 +0,0 @@
-/*
- * 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 ret = -1;
- int fd = 0;
- 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 ((fd = mkstemp(fname)) < 0) {
- dbgprintf("%s: Can't open file %s\n", __func__,
- fname);
- ret = -1;
- goto fail_mkstemp;
- }
-
- 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);
- ret= -ENOMEM;
- goto fail_calloc;
- }
-
- /* 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__);
- ret = -1;
- goto fail_bad_header;
- }
-
- h = (const struct arm64_image_header *)(kernel_uncompressed_buf);
-
- if (!arm64_header_check_magic(h)) {
- dbgprintf("%s: Bad arm64 image header.\n", __func__);
- ret = -1;
- goto fail_bad_header;
- }
-
- if (write(fd, kernel_uncompressed_buf,
- kernel_size) != kernel_size) {
- dbgprintf("%s: Can't write the uncompressed file %s\n",
- __func__, fname);
- ret = -1;
- goto fail_bad_header;
- }
-
- close(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);
- ret = -1;
- goto fail_bad_header;
- }
-
- unlink(fname);
-
- free(kernel_uncompressed_buf);
- free(fname);
-
- return kernel_fd;
-
-fail_bad_header:
- free(kernel_uncompressed_buf);
-
-fail_calloc:
- if (fd >= 0)
- close(fd);
-
- unlink(fname);
-
-fail_mkstemp:
- free(fname);
-
- return ret;
-}
-
-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");
-}
Index: kexec-tools/kexec/kexec.c
===================================================================
--- kexec-tools.orig/kexec/kexec.c
+++ kexec-tools/kexec/kexec.c
@@ -638,6 +638,21 @@ char *slurp_decompress_file(const char *
return kernel_buf;
}
+int copybuf_memfd(const char *kernel_buf, size_t size)
+{
+ int fd, count;
+
+ fd = memfd_create("kernel", MFD_ALLOW_SEALING);
+ if (fd == -1)
+ return fd;
+
+ count = write(fd, kernel_buf, size);
+ if (count < 0)
+ return -1;
+
+ return fd;
+}
+
static void update_purgatory(struct kexec_info *info)
{
static const uint8_t null_buf[256];
@@ -1263,7 +1278,7 @@ static int do_kexec_file_load(int filein
unsigned long flags) {
char *kernel;
- int kernel_fd, i;
+ int kernel_fd, i, fd;
struct kexec_info info;
int ret = 0;
char *kernel_buf;
@@ -1277,6 +1292,7 @@ static int do_kexec_file_load(int filein
info.kexec_flags = flags;
info.file_mode = 1;
+ info.kernel_fd = -1;
info.initrd_fd = -1;
if (!is_kexec_file_load_implemented())
@@ -1299,22 +1315,16 @@ static int do_kexec_file_load(int filein
/* slurp in the input kernel */
kernel_buf = slurp_decompress_file(kernel, &kernel_size);
+ fd = copybuf_memfd(kernel_buf, kernel_size);
+ if (fd < 0)
+ fprintf(stderr, "Failed to copy decompressed buf\n");
+ else {
+ kernel_fd = fd;
+ }
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) {
@@ -1324,12 +1334,19 @@ static int do_kexec_file_load(int filein
return EFAILED;
}
- ret = file_type[i].load(argc, argv, kernel_buf, kernel_size, &info);
- if (ret < 0) {
- fprintf(stderr, "Cannot load %s\n", kernel);
- close(kernel_fd);
- return ret;
- }
+ ret = file_type[i].load(argc, argv, kernel_buf, kernel_size, &info);
+ if (ret < 0) {
+ fprintf(stderr, "Cannot load %s\n", kernel);
+ close(kernel_fd);
+ return ret;
+ }
+
+ /*
+ * image type specific load functioin detect the capsule kernel type
+ * and create another fd for file load. For example the zboot kernel.
+ */
+ if (info.kernel_fd != -1)
+ kernel_fd = info.kernel_fd;
/*
* If there is no initramfs, set KEXEC_FILE_NO_INITRAMFS flag so that
Index: kexec-tools/kexec/kexec.h
===================================================================
--- kexec-tools.orig/kexec/kexec.h
+++ kexec-tools/kexec/kexec.h
@@ -164,6 +164,7 @@ struct kexec_info {
unsigned long file_mode :1;
/* Filled by kernel image processing code */
+ int kernel_fd;
int initrd_fd;
char *command_line;
int command_line_len;
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