[coreboot] Loading Linux payloads on RISC-V

[Jonathan Neuschäfer]

Hi,

we've discussed this briefly at OSFC: Linux's ELF file (vmlinux)
currently has segments starting at 0x0 (if you look at the physical
address field) and an entry point at 0xffffffe000000000:

> $ readelf -l vmlinux
> 
> Elf file type is EXEC (Executable file)
> Entry point 0xffffffe000000000
> There are 3 program headers, starting at offset 64
> 
> Program Headers:
>   Type           Offset             VirtAddr           PhysAddr
>                  FileSiz            MemSiz              Flags  Align
>   LOAD           0x0000000000001000 0xffffffe000000000 0x0000000000000000
>                  0x000000000000ffce 0x000000000000ffce  R E    0x1000
>   LOAD           0x0000000000011000 0xffffffe000010000 0x0000000000010000
>                  0x00000000002cda3c 0x00000000002cda3c  RWE    0x1000
>   NOTE           0x00000000002dea00 0xffffffe0002dda00 0x00000000002dda00
>                  0x000000000000003c 0x000000000000003c  R      0x4
> 
>  Section to Segment mapping:
>   Segment Sections...
>    00     .init.text
>    01     .init.data .exit.text .data..percpu .text .softirqentry.text .rodata __param __modver .srodata .data __bug_table .sdata .bss __ex_table .notes
>    02     .notes


coreboot's SELF loader rightly points out that 0x0 is not in RAM:

> Loading segment from ROM address 0x00000000200287b8
>   code (compression=0)
>   New segment dstaddr 0x0 memsize 0xffce srcaddr 0x2002880c filesize 0xffce
> Loading segment from ROM address 0x00000000200287d4
>   code (compression=0)
>   New segment dstaddr 0x10000 memsize 0x2cda3c srcaddr 0x200387da filesize 0x2cda3c
> Loading segment from ROM address 0x00000000200287f0
>   Entry Point 0xffffffe000000000
> SELF Payload doesn't target RAM:
> Failed Segment: 0x0, 65486 bytes
>  0. 0000000080000000-0000000080011fff: RAMSTAGE
>  1. 0000000080012000-000000008003ffff: RAM
>  2. 0000000080040000-0000000080044fff: RAMSTAGE
>  3. 0000000080045000-00000000fffdbfff: RAM
>  4. 00000000fffdc000-00000000ffffffff: CONFIGURATION TABLES
>  5. 0000000100000000-000000027fffffff: RAM
> Payload not loaded.


How should we solve this?

One option I see is to keep CONFIG_PAYLOAD_ELF as is, and add quirks to
CONFIG_PAYLOAD_LINUX.


Jonathan
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