On Friday 23 June 2017 02:25 PM, Hoeun Ryu wrote:
> Arm linux supports zImage with appended dtb (CONFIG_ARM_APPENDED_DTB) and
> the concatenated image is generated like `cat zImage dtb > zImage_w_dtb`.
>
> This patch is to support the concatednated zImage. This changes the
> priority of source of dtb file.
>
> 1. --dtb dtb_file
> 2. zImage_w_dtb <= newly added
> 3. /sys/firmware/fdt
> 4. /proc/device-tree
>
> Users don't need to specify dtb file in the command line and don't have to
> have /sys/firmware/fdt or /proc/device-tree if dtb is available in zImage.
any specific reason to not to add the new method as last preferred option?
Does it not work if there exist a /sys/firmware/fdt in case of a kernel booted
with "dtb appended zImage"?
>
> Signed-off-by: Hoeun Ryu <hoeun.ryu at gmail.com>
> ---
> kexec/arch/arm/kexec-arm.h | 1 +
> kexec/arch/arm/kexec-zImage-arm.c | 47 ++++++++++++++++++++++++++++++---------
> 2 files changed, 37 insertions(+), 11 deletions(-)
>
> diff --git a/kexec/arch/arm/kexec-arm.h b/kexec/arch/arm/kexec-arm.h
> index a74cce2..94695b7 100644
> --- a/kexec/arch/arm/kexec-arm.h
> +++ b/kexec/arch/arm/kexec-arm.h
> @@ -4,6 +4,7 @@
> #include <sys/types.h>
>
> #define SYSFS_FDT "/sys/firmware/fdt"
> +#define APPENDED_FDT ((char *)-1) /* it doesn't mean to be opened. */
> #define BOOT_BLOCK_VERSION 17
> #define BOOT_BLOCK_LAST_COMP_VERSION 16
>
> diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
> index 7f02b93..59f0003 100644
> --- a/kexec/arch/arm/kexec-zImage-arm.c
> +++ b/kexec/arch/arm/kexec-zImage-arm.c
> @@ -390,6 +390,7 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
> initrd_size = 0;
> use_atags = 0;
> dtb_file = NULL;
> + dtb_buf = NULL;
> while((opt = getopt_long(argc, argv, short_options, options, 0)) != -1) {
> switch(opt) {
> default:
> @@ -424,14 +425,6 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
> return -1;
> }
>
> - if (!use_atags && !dtb_file) {
> - int f;
> -
> - f = have_sysfs_fdt();
> - if (f)
> - dtb_file = SYSFS_FDT;
> - }
> -
> if (command_line) {
> command_line_len = strlen(command_line) + 1;
> if (command_line_len > COMMAND_LINE_SIZE)
> @@ -440,9 +433,6 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
> if (ramdisk)
> ramdisk_buf = slurp_file(ramdisk, &initrd_size);
>
> - if (dtb_file)
> - dtb_buf = slurp_file(dtb_file, &dtb_length);
> -
> if (len > 0x34) {
> const struct zimage_header *hdr;
> off_t size;
> @@ -459,6 +449,25 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
> (unsigned long long)size,
> (unsigned long long)len);
>
> + /* check if zImage has an appended dtb */
> + if (!dtb_file) {
> + if (fdt_check_header(buf + size) == 0) {
What if size >= len? I think, in that case there might not be a valid address
at buf+size and reading those area would lead in segmentation fault.
> + /*
> + * dtb_file won't be opened. It's set
> + * just to pass NULL checking.
> + */
> + dtb_file = APPENDED_FDT;
> + dtb_length = fdt_totalsize(buf + size);
> + dtb_buf = xmalloc(dtb_length);
> + memcpy(dtb_buf, buf+size, dtb_length);
> +
> + dbgprintf("found appended dtb, size 0x%llx\n",
> + (unsigned long long)dtb_length);
> +
> +
> + }
> + }
> +
> if (size > len) {
> fprintf(stderr,
> "zImage is truncated - file 0x%llx vs header 0x%llx\n",
> @@ -575,6 +584,22 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
> initrd_base = kernel_base + _ALIGN(len * 5, getpagesize());
> }
>
> + if (!use_atags && !dtb_file) {
> + int f;
> +
> + f = have_sysfs_fdt();
> + if (f)
> + dtb_file = SYSFS_FDT;
> + }
> +
> + /*
> + * dtb_buf can be allocated when checking zImage_with_dtb.
> + * dtb_buf won't be allocated in the logic if dtb_file is handed over
> + * in argv[].
> + */
> + if (dtb_file && !dtb_buf)
> + dtb_buf = slurp_file(dtb_file, &dtb_length);
> +
> if (use_atags) {
> /*
> * use ATAGs from /proc/atags
>
--
Pratyush
