Christophe Leroy <christophe.le...@csgroup.eu> writes: > In those hot functions that are called at every interrupt, any saved > cycle is worth it. > > interrupt_exit_user_prepare() and interrupt_exit_kernel_prepare() are > called from three places: > - From entry_32.S > - From interrupt_64.S > - From interrupt_exit_user_restart() and interrupt_exit_kernel_restart() > > In entry_32.S, there are inambiguously called based on MSR_PR: > > interrupt_return: > lwz r4,_MSR(r1) > addi r3,r1,STACK_FRAME_OVERHEAD > andi. r0,r4,MSR_PR > beq .Lkernel_interrupt_return > bl interrupt_exit_user_prepare > ... > .Lkernel_interrupt_return: > bl interrupt_exit_kernel_prepare > > In interrupt_64.S, that's similar: > > interrupt_return_\srr\(): > ld r4,_MSR(r1) > andi. r0,r4,MSR_PR > beq interrupt_return_\srr\()_kernel > interrupt_return_\srr\()_user: /* make backtraces match the _kernel > variant */ > addi r3,r1,STACK_FRAME_OVERHEAD > bl interrupt_exit_user_prepare > ... > interrupt_return_\srr\()_kernel: > addi r3,r1,STACK_FRAME_OVERHEAD > bl interrupt_exit_kernel_prepare > > In interrupt_exit_user_restart() and interrupt_exit_kernel_restart(), > MSR_PR is verified respectively by BUG_ON(!user_mode(regs)) and > BUG_ON(user_mode(regs)) prior to calling interrupt_exit_user_prepare() > and interrupt_exit_kernel_prepare(). > > The verification in interrupt_exit_user_prepare() and > interrupt_exit_kernel_prepare() are therefore useless and can be removed. > > Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> > Acked-by: Nicholas Piggin <npig...@gmail.com> > --- > arch/powerpc/kernel/interrupt.c | 2 -- > 1 file changed, 2 deletions(-)
I'll pick this one up independent of the other two patches. cheers
