Attention is currently required from: Nico Huber, Martin L Roth, Arthur Heymans, Felix Held.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/68648 )
Change subject: lib/Kconfig: Disable `DECOMPRESS_OFAST` for x86_64 ......................................................................
Patch Set 1:
(1 comment)
File src/lib/Kconfig:
https://review.coreboot.org/c/coreboot/+/68648/comment/1d5caaa8_c431c194 PS1, Line 121: USE_EXP_X86_64_SUPPORT
Can you use 'ARCH_RAMSTAGE_X86_64' (that's a good enough proxy for needing lzma decompression code + […]
It wouldn't make sense, though: the problem seems to be that `-Ofast` breaks the decompression algorithm itself when it's built for x86_64, which is part of postcar.
Even though coreboot doesn't support it yet, one could do something similar to UEFI: SEC and PEI stages (bootblock till postcar) are 32-bit code, whereas DXE onwards (ramstage onwards) are 64-bit code. In such a configuration, postcar would be 32-bit code and would still work, although decompressing the payload would likely fail.
Moreover, this could or could not be an issue for non-x86 platforms. If an x86_64 platform is ever introduced that only uses 64-bit mode, then this issue should be revisited.
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Angel Pons (Code Review)