[coreboot-gerrit] Change in coreboot[master]: fmap: Avoid unaligned access

[Julius Werner (Code Review)]

Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/40243 )

Change subject: fmap: Avoid unaligned access
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Patch Set 1: Code-Review-1

The general philosophy is that unaligned accesses need to be supported in common code. There are many places we would have to fix (not just here but also in CBFS and elsewhere) if that wasn't the case. All supported architectures have a way to allow unaligned accesses (although some of them require some platform-specific setup in early init code first).

The Zork PSP is an Arm platform (right)? In that case, you should enable paging and caching to get it to support unaligned accesses. You generally just need to run something like

mmu_init();
 mmu_config_range(0, 4096, DCACHE_OFF);
 mmu_config_range((uintptr_t)_sram / KiB, REGION_SIZE(sram) / KiB, DCACHE_WRITETHROUGH);
 dcache_mmu_enable();

in your bootblock_soc_init(). (Make sure to set the SRAM_START and SRAM_END symbols in your memlayout.ld and provide a 16KB TTB() region.)