CVS commit: [netbsd-9] src/sys

["Martin Husemann" <martin%netbsd.org@localhost>]

Module Name:    src
Committed By:   martin
Date:           Sun Sep  1 14:03:02 UTC 2019

Modified Files:
        src/sys/arch/arm/conf [netbsd-9]: Makefile.arm
        src/sys/dev/usb [netbsd-9]: if_axe.c

Log Message:
Pull up following revision(s) (requested by rin in ticket #146):

        sys/arch/arm/conf/Makefile.arm: revision 1.50
        sys/dev/usb/if_axe.c: revision 1.120

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

 -

PR kern/54486
Revert workaround introduced in rev 1.94:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/dev/usb/if_axe.c#rev1.94

This is a problem specific to ARMv6+, and addressed by
arch/arm/conf/Makefile.arm rev 1.50:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/arm/conf/Makefile.arm#rev1.50

XXX
pullup netbsd-9


To generate a diff of this commit:
cvs rdiff -u -r1.49 -r1.49.4.1 src/sys/arch/arm/conf/Makefile.arm
cvs rdiff -u -r1.102.2.1 -r1.102.2.2 src/sys/dev/usb/if_axe.c

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