[PATCH v2] ARM: net: JIT compiler for packet filters

Nicolas Pitre nicolas.pitre at linaro.org
Thu Dec 22 21:26:47 EST 2011

On Thu, 22 Dec 2011, David Laight wrote:

> > In principle, the condition could be __LINUX_ARM_ARCH__ < 5, since the
> > bx instruction is guaranteed to be available on all ARMv5 CPUs and
> > later (ARMv5T is not required).
> Can't this code look at the actual cpu being used, and
> generate the relevant 'return' instruction?
> (Instead of trying to use some compile-time value.)

There is really no point doing so.  We intend to ultimately have a 
kernel that may support ARMv5 and lower, and another kernel to support 
ARMv6 and ARMv7.  So in a given context, either bx is always available 
(ARMv6+) or never required (ARMv5-).


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