[coreboot] Loading Linux payloads on RISC-V

Philipp Hug philipp at hug.cx
Wed Sep 26 22:29:00 CEST 2018


In my local tree I just added the ram address in selfboot.
Doing this beforehand with cbfstool would be even better. (E.g. only when
choosing linux payload)

The FIT probably needs to be created by distro tools: assembling kernel, dt
and initramfs.

On Wed, Sep 26, 2018, 17:42 ron minnich <rminnich at gmail.com> wrote:

> But the kernel can start anywhere. I don't see a reason to do this complex
> objcopy step when all that is needed is to have cbfstool set some entries
> in the SELF or just have selfboot use "0" to mean "somewhere useful"? Did I
> miss something?
>
> On Tue, Sep 25, 2018 at 10:32 PM 王翔 <wxjstz at 126.com> wrote:
>
>> This elf file is position-independent and can be loaded to any location.
>> We can add a simple script to handle it.
>>
>> 1. Convert vmlinux to binary by objcopy, the binary file name is flat_file
>>
>> 2. Write a simple assembly file (tmp.S), convert binary to object, the
>> file name is obj_file
>> ```
>> .section .text
>> .globl _start
>> _start:
>> .incbin "flat_file"
>> ```
>> command: as tmp.S -o obj_file
>>
>> 3. Relink. Linker script like this(tmp.ld):
>> ```
>> ENTRY(_start)
>>
>> SECTIONS {
>>   . = target_address;
>>   .text : { *(.text) }
>> }
>> ```
>> command: ld -T tmp.ld obj_file
>>
>>
>>
>> 在2018年09月25 20时51分, "Philipp Hug"<philipp at hug.cx>写道:
>>
>>
>> Am Di., 25. Sep. 2018 um 13:50 Uhr schrieb Jonathan Neuschäfer <
>> j.neuschaefer at gmx.net>:
>>
>>> Would FIT support require discussion/cooperation with other projects
>>> like Linux or u-boot?
>>>
>>> What seems to be missing is the kernel image format to be used within
>> the FIT. e.g. look at arm64:
>> https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/head.S#L73
>>
>> https://github.com/coreboot/coreboot/blob/master/src/arch/arm64/fit_payload.c#L29
>>
>>
>> Philipp
>>
>>
>>
>>
>>
>>
>>
>
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