PR/54486 CVS commit: src/sys/arch/arm/conf

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

The following reply was made to PR kern/54486; it has been noted by GNATS.

From: "Rin Okuyama" <rin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/54486 CVS commit: src/sys/arch/arm/conf
Date: Mon, 26 Aug 2019 17:18:42 +0000

 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.