[OE-core] [PATCH 1/2] image_types: Add elf image type

[Raymond Danks]

On 06/27/2012 02:34 PM, Raymond Danks wrote:
> Hi Darren,
>
> Thanks for the feedback.
>
> On 06/25/2012 10:58 AM, Darren Hart wrote:
>> Hi Raymond,
>>
>> On 06/22/2012 01:22 PM, Raymond Danks wrote:
>>> On x86, an ELF image file may be stored as a coreboot payload.
>>> The image file is constructed, using the mkelfimage utility,
>>> from a kernel and an initrd.
>>>
>> Is this usable solely as a coreboot payload?
>>
>> The reason I ask is there have been requests to be able to build the
>> kernel+initramfs that the Linux make system supports. The coreboot wiki
>> suggests that this may be sufficient in lieu of the mkelfimage format.
>>
>> http://www.coreboot.org/Mkelfimage
>>
>> If we can satisfy both goals with one image type, I would prefer we do
>> that, at least for the core.
> I have not tried this.
>
> I prefer the mkelfimage mechanism over the linux kernel's mechanism 
> due to the manner in which the OpenEmbedded build process is laid 
> out.  In my experience, the rootfs/initrd is constructed *after* the 
> kernel and is not necessarily available for inclusion by the kernel 
> build.
>
> Of course, if you have a patch for this, I'd be happy to give that a try.

One more point of interest I guess:

I was able to boot this elf file using syslinux and mboot.c32.  So, 
depending upon your use case, it may be possible to use this elf file 
instead of the kernel+initramfs.

>>> Signed-off-by: Raymond Danks<ray.danks at se-eng.com>
>>> ---
>>> This was originally submitted to the openembedded project:
>>> http://patches.openembedded.org/patch/7689/
>>>
>>> Resubmitting to oe-core for review prior to commit in 
>>> openembedded-core.
>>>
>>>   meta/classes/image_types.bbclass |   18 +++++++++++++++++-
>>>   1 files changed, 17 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/meta/classes/image_types.bbclass 
>>> b/meta/classes/image_types.bbclass
>>> index 55f122e..bbca20c 100644
>>> --- a/meta/classes/image_types.bbclass
>>> +++ b/meta/classes/image_types.bbclass
>>> @@ -7,6 +7,12 @@ def get_imagecmds(d):
>>>       ctypes = d.getVar('COMPRESSIONTYPES', True).split()
>>>       cimages = {}
>>>
>>> +    if "elf" in alltypes:
>>> +        alltypes.remove("elf")
>>> +        if "cpio.gz" not in alltypes:
>>> +                alltypes.append("cpio.gz")
>>> +        alltypes.append("elf")
>>> +
>> What is the goal of this? Do you just need cpio.gz to appear before elf
>> in the list?
> Yes.  The cpio.gz is an input to the mkelfimage command below.
>> If so, can that just be checked for at the time of adding
>> elf the first time?
> Possibly.  Can you tell me where this is done?
>>
>>>       # Filter out all the compressed images from types
>>>       for type in alltypes:
>>>           basetype = None
>>> @@ -173,6 +179,14 @@ IMAGE_CMD_cpio () {
>>>       cd ${IMAGE_ROOTFS}&&  (find . | cpio -o -H 
>>> newc>${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.cpio)
>>>   }
>>>
>>> +ELF_KERNEL ?= ${STAGING_DIR_HOST}/kernel/bzImage
>> There are various kernel image types. Is the elf format only valid with
>> bzImage?
> The mkelfimage documentation indicates that bzImage and vmlinux are 
> supported.  I have only worked with bzImage.  That said, I agree that 
> this is more appropriate:
>
> ELF_KERNEL ?= ${STAGING_DIR_HOST}/kernel/${KERNEL_IMAGETYPE}
>>
>>> +ELF_APPEND ?= "ramdisk_size=32768 root=/dev/ram0 rw console="
>> We would need to parameterize ramdisk_size.
> I am hoping that this initial patch will satisfy most needs.  I agree 
> that changes may need to be made as needs become more specific.
>>
>> -- 
>> Darren
>>
>>> +
>>> +IMAGE_CMD_elf () {
>>> +    test -f ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.elf&&  rm -f 
>>> ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.elf
>>> +    mkelfImage --kernel=${ELF_KERNEL} 
>>> --initrd=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.cpio.gz 
>>> --output=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.elf 
>>> --append='${ELF_APPEND}' ${EXTRA_IMAGECMD}
>>> +}
>>> +
>>>   UBI_VOLNAME ?= "${MACHINE}-rootfs"
>>>
>>>   IMAGE_CMD_ubi () {
>>> @@ -199,6 +213,7 @@ EXTRA_IMAGECMD_ext2 ?= "-i 8192"
>>>   EXTRA_IMAGECMD_ext3 ?= "-i 8192"
>>>   EXTRA_IMAGECMD_ext4 ?= "-i 8192"
>>>   EXTRA_IMAGECMD_btrfs ?= ""
>>> +EXTRA_IMAGECMD_elf ?= ""
>>>
>>>   IMAGE_DEPENDS = ""
>>>   IMAGE_DEPENDS_jffs2 = "mtd-utils-native"
>>> @@ -210,11 +225,12 @@ IMAGE_DEPENDS_ext4 = "genext2fs-native 
>>> e2fsprogs-native"
>>>   IMAGE_DEPENDS_btrfs = "btrfs-tools-native"
>>>   IMAGE_DEPENDS_squashfs = "squashfs-tools-native"
>>>   IMAGE_DEPENDS_squashfs-lzma = "squashfs-lzma-tools-native"
>>> +IMAGE_DEPENDS_elf = "virtual/kernel mkelfimage-native"
>>>   IMAGE_DEPENDS_ubi = "mtd-utils-native"
>>>   IMAGE_DEPENDS_ubifs = "mtd-utils-native"
>>>
>>>   # This variable is available to request which values are suitable 
>>> for IMAGE_FSTYPES
>>> -IMAGE_TYPES = "jffs2 sum.jffs2 cramfs ext2 ext2.gz ext2.bz2 ext3 
>>> ext3.gz ext2.lzma btrfs live squashfs squashfs-lzma ubi tar tar.gz 
>>> tar.bz2 tar.xz cpio cpio.gz cpio.xz cpio.lzma vmdk"
>>> +IMAGE_TYPES = "jffs2 sum.jffs2 cramfs ext2 ext2.gz ext2.bz2 ext3 
>>> ext3.gz ext2.lzma btrfs live squashfs squashfs-lzma ubi tar tar.gz 
>>> tar.bz2 tar.xz cpio cpio.gz cpio.xz cpio.lzma vmdk elf"
>>>
>>>   COMPRESSIONTYPES = "gz bz2 lzma xz"
>>>   COMPRESS_CMD_lzma = "lzma -k -f -7 ${IMAGE_NAME}.rootfs.${type}"
>>>
>