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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 07/23] ARM: entry: no need to increase preempt count for IRQ handlers
Date: Wed, 29 Jun 2011 10:21:14 +0100	[thread overview]
Message-ID: <E1QbqxO-0002F8-Gm@rmk-PC.arm.linux.org.uk> (raw)
In-Reply-To: <20110629091853.GK21898@n2100.arm.linux.org.uk>

irq_enter() and irq_exit() already take care of the preempt_count
handling for interrupts, which increment and decrement the hardirq
bits of the preempt count.  So we can remove the preempt count handing
in our IRQ entry/exit assembly, like x86 did some 9 years ago.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/kernel/entry-armv.S |   27 ++++-----------------------
 1 files changed, 4 insertions(+), 23 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 6855f6d..1e5f387 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -220,16 +220,12 @@ __irq_svc:
 #ifdef CONFIG_TRACE_IRQFLAGS
 	bl	trace_hardirqs_off
 #endif
-#ifdef CONFIG_PREEMPT
-	get_thread_info tsk
-	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
-	add	r7, r8, #1			@ increment it
-	str	r7, [tsk, #TI_PREEMPT]
-#endif
 
 	irq_handler
+
 #ifdef CONFIG_PREEMPT
-	str	r8, [tsk, #TI_PREEMPT]		@ restore preempt count
+	get_thread_info tsk
+	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
 	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
 	teq	r8, #0				@ if preempt count != 0
 	movne	r0, #0				@ force flags to 0
@@ -432,23 +428,8 @@ __irq_usr:
 	bl	trace_hardirqs_off
 #endif
 
-	get_thread_info tsk
-#ifdef CONFIG_PREEMPT
-	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
-	add	r7, r8, #1			@ increment it
-	str	r7, [tsk, #TI_PREEMPT]
-#endif
-
 	irq_handler
-#ifdef CONFIG_PREEMPT
-	ldr	r0, [tsk, #TI_PREEMPT]
-	str	r8, [tsk, #TI_PREEMPT]
-	teq	r0, r7
- ARM(	strne	r0, [r0, -r0]	)
- THUMB(	movne	r0, #0		)
- THUMB(	strne	r0, [r0]	)
-#endif
-
+	get_thread_info tsk
 	mov	why, #0
 	b	ret_to_user_from_irq
  UNWIND(.fnend		)
-- 
1.7.4.4

  parent reply	other threads:[~2011-06-29  9:21 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-29  9:18 [PATCH 00/23] entry assembly cleanups Russell King - ARM Linux
2011-06-29  9:19 ` [PATCH 01/23] ARM: entry: remove unused irq_prio_table macro Russell King - ARM Linux
2011-06-29  9:19 ` [PATCH 02/23] ARM: entry: shark: don't directly reference registers in macros Russell King - ARM Linux
2011-06-29  9:19 ` [PATCH 03/23] ARM: entry: prefetch/data abort helpers: convert to macros Russell King - ARM Linux
2011-06-29  9:20 ` [PATCH 00/23] entry assembly cleanups Russell King - ARM Linux
2011-06-29  9:20 ` [PATCH 04/23] ARM: entry: prefetch/data abort helpers: avoid corrupting r4 Russell King - ARM Linux
2011-06-29  9:20 ` [PATCH 05/23] ARM: entry: abort-macro: specify registers to be used for macros Russell King - ARM Linux
2011-06-29  9:20 ` [PATCH 06/23] ARM: entry: abort-macro: simplify do_ldrd_abort Russell King - ARM Linux
2011-06-29  9:21 ` Russell King - ARM Linux [this message]
2011-06-29  9:21 ` [PATCH 08/23] ARM: entry: no need to check parent IRQ mask in IRQ handler return Russell King - ARM Linux
2011-06-29  9:21 ` [PATCH 09/23] ARM: entry: rejig register allocation in exception entry handlers Russell King - ARM Linux
2011-06-29  9:22 ` [PATCH 10/23] ARM: entry: prefetch abort helper: pass aborted pc in r4 rather than r0 Russell King - ARM Linux
2011-06-29  9:22 ` [PATCH 11/23] ARM: entry: avoid enabling interrupts in prefetch/data abort handlers Russell King - ARM Linux
2011-06-29 20:05   ` Will Deacon
2011-06-30  9:27     ` Russell King - ARM Linux
2011-06-30 21:51       ` Will Deacon
2011-06-29  9:22 ` [PATCH 12/23] ARM: entry: instrument svc undefined exception handler with irqtrace Russell King - ARM Linux
2011-06-29  9:23 ` [PATCH 13/23] ARM: entry: instrument usr exception handlers with irqsoff tracing Russell King - ARM Linux
2011-06-29  9:23 ` [PATCH 14/23] ARM: entry: consolidate trace_hardirqs_off into (svc|usr)_entry macros Russell King - ARM Linux
2011-06-29  9:23 ` [PATCH 15/23] ARM: entry: re-allocate registers in irq entry assembly macros Russell King - ARM Linux
2011-06-29  9:24 ` [PATCH 16/23] ARM: entry: prefetch abort: tail-call the main prefetch abort handler Russell King - ARM Linux
2011-06-29  9:24 ` [PATCH 17/23] ARM: entry: data abort: arrange for CPU abort helpers to take pc/psr in r4/r5 Russell King - ARM Linux
2011-06-29  9:24 ` [PATCH 18/23] ARM: entry: data abort: avoid using r2 in abort helpers Russell King - ARM Linux
2011-06-29  9:25 ` [PATCH 19/23] ARM: entry: data abort: tail-call the main data abort handler Russell King - ARM Linux
2011-06-29  9:25 ` [PATCH 20/23] ARM: entry: data abort: use r2 as base of pt_regs rather than stack Russell King - ARM Linux
2011-06-29  9:25 ` [PATCH 21/23] ARM: entry: data abort: always use r6 for offset Russell King - ARM Linux
2011-06-29  9:26 ` [PATCH 22/23] ARM: entry: data abort: ensure r5 is preserved by abort functions Russell King - ARM Linux
2011-06-29  9:26 ` [PATCH 23/23] ARM: entry: no need to reload the SPSR value from struct pt_regs Russell King - ARM Linux
2011-06-29 14:53 ` [PATCH 00/23] entry assembly cleanups Jean-Christophe PLAGNIOL-VILLARD

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