diff options
| author | Vineet Gupta | 2013-07-09 17:06:40 +0530 |
|---|---|---|
| committer | Vineet Gupta | 2013-08-26 09:40:25 +0530 |
| commit | fce16bc35ae4a45634f3dc348d8d297a25c277cf (patch) | |
| tree | ad8bd83bf1ec3210208bad9a566a7585583ee876 /arch/arc | |
| parent | 37f3ac498c988536f0d42b4659fb5d2c050b2f96 (diff) | |
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 <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc')
| -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 d99f79bcf865..b68b53f458d1 100644 --- a/arch/arc/include/asm/irqflags.h +++ b/arch/arc/include/asm/irqflags.h @@ -157,13 +157,6 @@ 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 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 |