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Date: Sat, 07 Feb 2009 21:14:36 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] x86: check_timer cleanup
Impact: remove extra unmask, and pair disable/enable
for edge trigger io-apic routing, already unmasked via setup_IO_APIC_irq,
so don't unmask it again.
also do call local_irq_disable() between timer_irq_works(), between it does call
local_irq_enable() inside.
also remove not needed apic version reading for 64bit
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/kernel/io_apic.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
Index: linux-2.6/arch/x86/kernel/io_apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/io_apic.c
+++ linux-2.6/arch/x86/kernel/io_apic.c
@@ -1660,7 +1660,7 @@ static void __init setup_timer_IRQ0_pin(
* to the first CPU.
*/
entry.dest_mode = apic->irq_dest_mode;
- entry.mask = 1; /* mask IRQ now */
+ entry.mask = 0; /* don't mask IRQ for edge */
entry.dest = apic->cpu_mask_to_apicid(apic->target_cpus());
entry.delivery_mode = apic->irq_delivery_mode;
entry.polarity = 0;
@@ -2866,14 +2866,10 @@ static inline void __init check_timer(vo
int cpu = boot_cpu_id;
int apic1, pin1, apic2, pin2;
unsigned long flags;
- unsigned int ver;
int no_pin1 = 0;
local_irq_save(flags);
- ver = apic_read(APIC_LVR);
- ver = GET_APIC_VERSION(ver);
-
/*
* get/set the timer IRQ vector:
*/
@@ -2892,7 +2888,13 @@ static inline void __init check_timer(vo
apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
init_8259A(1);
#ifdef CONFIG_X86_32
- timer_ack = (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver));
+ {
+ unsigned int ver;
+
+ ver = apic_read(APIC_LVR);
+ ver = GET_APIC_VERSION(ver);
+ timer_ack = (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver));
+ }
#endif
pin1 = find_isa_irq_pin(0, mp_INT);
@@ -2931,8 +2933,17 @@ static inline void __init check_timer(vo
if (no_pin1) {
add_pin_to_irq_cpu(cfg, cpu, apic1, pin1);
setup_timer_IRQ0_pin(apic1, pin1, cfg->vector);
+ } else {
+ /* for edge trigger, setup_IO_APIC_irq already
+ * leave it unmasked.
+ * so only need to unmask if it is level-trigger
+ * do we really have level trigger timer?
+ */
+ int idx;
+ idx = find_irq_entry(apic1, pin1, mp_INT);
+ if (idx != -1 && irq_trigger(idx))
+ unmask_IO_APIC_irq_desc(desc);
}
- unmask_IO_APIC_irq_desc(desc);
if (timer_irq_works()) {
if (nmi_watchdog == NMI_IO_APIC) {
setup_nmi();
@@ -2946,6 +2957,7 @@ static inline void __init check_timer(vo
if (intr_remapping_enabled)
panic("timer doesn't work through Interrupt-remapped IO-APIC");
#endif
+ local_irq_disable();
clear_IO_APIC_pin(apic1, pin1);
if (!no_pin1)
apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
@@ -2960,7 +2972,6 @@ static inline void __init check_timer(vo
*/
replace_pin_at_irq_cpu(cfg, cpu, apic1, pin1, apic2, pin2);
setup_timer_IRQ0_pin(apic2, pin2, cfg->vector);
- unmask_IO_APIC_irq_desc(desc);
enable_8259A_irq(0);
if (timer_irq_works()) {
apic_printk(APIC_QUIET, KERN_INFO "....... works.\n");
@@ -2975,6 +2986,7 @@ static inline void __init check_timer(vo
/*
* Cleanup, just in case ...
*/
+ local_irq_disable();
disable_8259A_irq(0);
clear_IO_APIC_pin(apic2, pin2);
apic_printk(APIC_QUIET, KERN_INFO "....... failed.\n");
@@ -3000,6 +3012,7 @@ static inline void __init check_timer(vo
apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
goto out;
}
+ local_irq_disable();
disable_8259A_irq(0);
apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
apic_printk(APIC_QUIET, KERN_INFO "..... failed.\n");
@@ -3017,6 +3030,7 @@ static inline void __init check_timer(vo
apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
goto out;
}
+ local_irq_disable();
apic_printk(APIC_QUIET, KERN_INFO "..... failed :(.\n");
panic("IO-APIC + timer doesn't work! Boot with apic=debug and send a "
"report. Then try booting with the 'noapic' option.\n");
--
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