On Tue, 13 Dec 2016, Matt Redfearn wrote: > diff --git a/arch/mips/include/asm/stackframe.h > b/arch/mips/include/asm/stackframe.h > index eebf39549606..e13164daf9c2 100644 > --- a/arch/mips/include/asm/stackframe.h > +++ b/arch/mips/include/asm/stackframe.h > @@ -216,12 +216,20 @@ > LONG_S $25, PT_R25(sp) > LONG_S $28, PT_R28(sp) > LONG_S $31, PT_R31(sp) > + > + /* Set thread_info if we're coming from user mode */ > + mfc0 k0, CP0_STATUS > + sll k0, 3 /* extract cu0 bit */ > + bltz k0, 9f > + nop > +
Have you actually verified the machine code generated as expected with such a change? This supposedly delay-slot NOP can be dropped as this is `.set reorder' code, so GAS will have scheduled a NOP itself already, having found there is an SLL->BLTZ data dependency and consequently the two instructions cannot be swapped. So now there'll be an extraneous NOP there, wasting code space and execution time. Maciej
