diff options
| author | rin <rin@NetBSD.org> | 2019-08-26 17:18:42 +0000 |
|---|---|---|
| committer | rin <rin@NetBSD.org> | 2019-08-26 17:18:42 +0000 |
| commit | 59b03441e71de7ea46166177d6ba40ba06e439ea (patch) | |
| tree | b97b2f33986c8f864d6d9cbb89f0aa040d7fc32d /sys | |
| parent | a6fbed0cd360a5346f582aaf8e0c325bd471f100 (diff) | |
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
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/arch/arm/conf/Makefile.arm | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/sys/arch/arm/conf/Makefile.arm b/sys/arch/arm/conf/Makefile.arm index ae735a325a4..d09a57e16c6 100644 --- a/sys/arch/arm/conf/Makefile.arm +++ b/sys/arch/arm/conf/Makefile.arm @@ -1,4 +1,4 @@ -# $NetBSD: Makefile.arm,v 1.49 2018/09/22 12:24:01 rin Exp $ +# $NetBSD: Makefile.arm,v 1.50 2019/08/26 17:18:42 rin Exp $ # Makefile for NetBSD # @@ -53,6 +53,26 @@ CPPFLAGS.cpufunc_asm_armv6.S+= -mcpu=arm1136j-s CPPFLAGS.cpufunc_asm_arm11.S+= -mcpu=arm1136j-s CPPFLAGS.cpufunc_asm_xscale.S+= -mcpu=xscale +.if !empty(MACHINE_ARCH:Mearmv6*) || !empty(MACHINE_ARCH:Mearmv7*) +# XXX +# +# 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. +# +# See PR kern/54486 for more details. +CFLAGS+= -mno-unaligned-access +.endif + ## ## (3) libkern and compat ## |
