2020-10-26 16:14:57

by Chuanhong Guo

Subject: [PATCH] MIPS: zboot: put appended dtb into a section

This will make a separated section for dtb appear in ELF, and we can
then use objcopy to patch a dtb into vmlinuz when RAW_APPENDED_DTB
is set in kernel config.

command to patch a dtb:
objcopy --set-section-flags=.appended_dtb=alloc,contents \
--update-section=.appended_dtb=<target>.dtb vmlinuz

Signed-off-by: Chuanhong Guo <[email protected]>
---
Note:
This should supersede this patch on linux-mips:
[2/2] mips: boot compressed: add support for vlinuz ELF DTB [0]

[0] https://patchwork.kernel.org/project/linux-mips/patch/[email protected]/

arch/mips/boot/compressed/ld.script | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/mips/boot/compressed/ld.script b/arch/mips/boot/compressed/ld.script
index 2ed08fbef8e7..0ebb667274d6 100644
--- a/arch/mips/boot/compressed/ld.script
+++ b/arch/mips/boot/compressed/ld.script
@@ -31,9 +31,12 @@ SECTIONS
CONSTRUCTORS
. = ALIGN(16);
}
- __appended_dtb = .;
- /* leave space for appended DTB */
- . += 0x100000;
+
+ .appended_dtb : {
+ __appended_dtb = .;
+ /* leave space for appended DTB */
+ . += 0x100000;
+ }

_edata = .;
/* End of data section */
--
2.26.2

2020-10-26 17:05:22

by John Thomson

Subject: Re: [PATCH] MIPS: zboot: put appended dtb into a section

On Mon, 26 Oct 2020, at 12:29, Chuanhong Guo wrote:
> This will make a separated section for dtb appear in ELF, and we can
> then use objcopy to patch a dtb into vmlinuz when RAW_APPENDED_DTB
> is set in kernel config.

Thank you Chuanhong Guo, this worked for me.

I have successfully network boot tested this change on ath79 hardware:
- kernel vmlinuz.bin
then appended DTB, and packed into a uImage (out of kernel tree)
- kernel vmlinuz
then updated ELF DTB appended_dtb section, and ELF booted

Cheers,
--
John Thomson

2020-11-06 10:56:49

by Thomas Bogendoerfer

Subject: Re: [PATCH] MIPS: zboot: put appended dtb into a section

On Mon, Oct 26, 2020 at 08:29:25PM +0800, Chuanhong Guo wrote:
> This will make a separated section for dtb appear in ELF, and we can
> then use objcopy to patch a dtb into vmlinuz when RAW_APPENDED_DTB
> is set in kernel config.
>
> command to patch a dtb:
> objcopy --set-section-flags=.appended_dtb=alloc,contents \
> --update-section=.appended_dtb=<target>.dtb vmlinuz
>
> Signed-off-by: Chuanhong Guo <[email protected]>
> ---
> Note:
> This should supersede this patch on linux-mips:
> [2/2] mips: boot compressed: add support for vlinuz ELF DTB [0]
>
> [0] https://patchwork.kernel.org/project/linux-mips/patch/[email protected]/
>
> arch/mips/boot/compressed/ld.script | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)

applied to mips-next.

Thomas.

--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]