From fce16bc35ae4a45634f3dc348d8d297a25c277cf Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Tue, 9 Jul 2013 17:06:40 +0530 Subject: ARC: Entry Handler tweaks: Optimize away redundant IRQ_DISABLE_SAVE In the exception return path, for both U/K cases, intr are already disabled (for various existing reasons). So when we drop down to @restore_regs, we need not redo that. There was subtle issue - when intr were NOT being disabled for ret-to-kernel-but-no-preemption case - now fixed by moving the IRQ_DISABLE further up in @resume_kernel_mode. So what do we gain: * Shaves off a few insn in return path. * Eliminates the need for IRQ_DISABLE_SAVE assembler macro for ARCv2 hence allows for entry code sharing. Signed-off-by: Vineet Gupta --- arch/arc/kernel/entry.S | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/arc/kernel/entry.S') diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 059ca94e3df8..b908dde8a331 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -612,6 +612,9 @@ resume_kernel_mode: #ifdef CONFIG_PREEMPT + ; This is a must for preempt_schedule_irq() + IRQ_DISABLE r9 + ; Can't preempt if preemption disabled GET_CURR_THR_INFO_FROM_SP r10 ld r8, [r10, THREAD_INFO_PREEMPT_COUNT] @@ -621,8 +624,6 @@ resume_kernel_mode: ld r9, [r10, THREAD_INFO_FLAGS] bbit0 r9, TIF_NEED_RESCHED, restore_regs - IRQ_DISABLE r9 - ; Invoke PREEMPTION bl preempt_schedule_irq @@ -635,12 +636,11 @@ resume_kernel_mode: ; ; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap) ; IRQ shd definitely not happen between now and rtie +; All 2 entry points to here already disable interrupts restore_regs : - ; Disable Interrupts while restoring reg-file back - ; XXX can this be optimised out - IRQ_DISABLE_SAVE r9, r10 ;@r10 has prisitine (pre-disable) copy + lr r10, [status32] ; Restore REG File. In case multiple Events outstanding, ; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None -- cgit