[U-Boot] [PATCH] arm: enable unaligned access on ARMv7

Lucas Stach dev at lynxeye.de
Tue Jun 5 21:06:20 CEST 2012


Hi Stephen,

Am Dienstag, den 05.06.2012, 12:42 -0600 schrieb Stephen Warren:
> On 06/05/2012 11:47 AM, Lucas Stach wrote:
> > Recent toolchains default to using the hardware feature for unaligned access on
> > ARM v7, rather than doing the software fallback. According to ARM this is safe
> > as all v7 implementations have to support this feature.
> > (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/BABJFFAE.html)
> > 
> > To avoid CPU hangs when doing unaligned memory access, we have to turn off
> > alignment checking in our CPU initialisation code.
> > (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0491c/CIHCGCFD.html)
> 
> Does this behavior change trickle down to Linux/... too, or would an OS
> completely re-initialize this state, and hence not be affected?
> 

Linux in particular does reinitialize this state and I expect any
reasonable OS to do so.

-- Lucas



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