CVS commit: src/sys/arch/arm/conf

["Rin Okuyama" <rin%netbsd.org@localhost>]

Module Name:    src
Committed By:   rin
Date:           Mon Aug 26 17:18:42 UTC 2019

Modified Files:
        src/sys/arch/arm/conf: Makefile.arm

Log Message:
PR kern/54486

Workaround for alignment faults on ARMv6+, at least occur with
axe(4) and athn(4) drivers.

For ARMv6+, unaligned access is enabled by default. However, it
cannot be used for non-cacheable memory, which is used as DMA
buffers. This results in alignment faults above. A real fix is
to use cacheable memory as DMA buffers. However, it breaks some
drivers, awge(4) and vchiq(4) at least.

Until we figure out problems and fix them, we choose a fail-safe
workaround here; forbid unaligned memory access for whole kernel.
Affects on performance is negligibly small as far as we can see.

XXX
pullup netbsd-9


To generate a diff of this commit:
cvs rdiff -u -r1.49 -r1.50 src/sys/arch/arm/conf/Makefile.arm

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.