diff options
| author | Vineet Gupta <vgupta@synopsys.com> | 2013-07-09 17:06:40 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-13 13:59:42 +0200 |
| commit | 27dd47db1ba11a6f34d158a7dfa4c5bd78f81d1f (patch) | |
| tree | 4795921fc8e077cd80e6095b787fe5ae6ebe6a2a | |
| parent | 1a43738d057559e87e0036e25c33715d6eff11ed (diff) | |
ARC: Entry Handler tweaks: Optimize away redundant IRQ_DISABLE_SAVE
commit fce16bc35ae4a45634f3dc348d8d297a25c277cf upstream.
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 <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arc/include/asm/irqflags.h | 7 | ||||
| -rw-r--r-- | arch/arc/kernel/entry.S | 10 |
2 files changed, 5 insertions, 12 deletions
diff --git a/arch/arc/include/asm/irqflags.h b/arch/arc/include/asm/irqflags.h index eac07166820..c29d56587bf 100644 --- a/arch/arc/include/asm/irqflags.h +++ b/arch/arc/include/asm/irqflags.h @@ -137,13 +137,6 @@ static inline void arch_unmask_irq(unsigned int irq) flag \scratch .endm -.macro IRQ_DISABLE_SAVE scratch, save - lr \scratch, [status32] - mov \save, \scratch /* Make a copy */ - bic \scratch, \scratch, (STATUS_E1_MASK | STATUS_E2_MASK) - flag \scratch -.endm - .macro IRQ_ENABLE scratch lr \scratch, [status32] or \scratch, \scratch, (STATUS_E1_MASK | STATUS_E2_MASK) diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 922150e153e..57f38333834 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -653,6 +653,9 @@ 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] @@ -662,8 +665,6 @@ 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 @@ -676,12 +677,11 @@ 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] #ifdef CONFIG_ARC_CURR_IN_REG ; Restore User R25 |