Subject: [PATCH] ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+

From: [email-masked] (Tony Lindgren)
Date: Wed, 2 Jul 2014 02:02:18 -0700

* Russell King <[email-masked]> [140701 09:01]:
> ARMv6 and greater introduced a new instruction ("bx") which can be used
> to return from function calls.  Recent CPUs perform better when the
> "bx lr" instruction is used rather than the "mov pc, lr" instruction,
> and this sequence is strongly recommended to be used by the ARM
> architecture manual (section A.4.1.1).
> 
> We provide a new macro "ret" with all its variants for the condition
> code which will resolve to the appropriate instruction.
> 
> Rather than doing this piecemeal, and miss some instances, change all
> the "mov pc" instances to use the new macro, with the exception of
> the "movs" instruction and the kprobes code.  This allows us to detect
> the "mov pc, lr" case and fix it up - and also gives us the possibility
> of deploying this for other registers depending on the CPU selection.
> 
> Signed-off-by: Russell King <[email-masked]>

Seems to boot fine for omaps:

Tested-by: Tony Lindgren <[email-masked]>