On 2018-09-26 10:29 PM, Philipp Hug wrote:
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 proposed mechanism was already implemented here: https://review.coreboot.org/#/c/coreboot/+/13762/
We decided to use FIT instead, as it has the following advantages: * Supports architecture specific calling conventions * Supports devicetree and initrd * Supports PIE
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@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@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.
- Convert vmlinux to binary by objcopy, the binary file name is
flat_file
- 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
- 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@hug.cx写道:
Am Di., 25. Sep. 2018 um 13:50 Uhr schrieb Jonathan Neuschäfer j.neuschaefer@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....
As the riscv kernel doesn't have a header, just place it anywhere in usable RAM and set the entrypoint to the same address. It looks like it's very easy to add FIT support.
Regards, Patrick
Philipp