x86: check_timer cleanup

Impact: make check-timer more robust potentially solve boot fragility

For edge trigger io-apic routing, we already unmasked the pin via
setup_IO_APIC_irq(), so don't unmask it again.

Also call local_irq_disable() between timer_irq_works(), because it
calls local_irq_enable() inside.

Also remove not needed apic version reading for 64-bit

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 22 insertions, 8 deletions

diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index e5be9f35ea54..855209a1b172 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -1657,7 +1657,7 @@ static void __init setup_timer_IRQ0_pin(unsigned int apic_id, unsigned int 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;
@@ -2863,14 +2863,10 @@ static inline void __init check_timer(void)
         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:
          */
@@ -2889,7 +2885,13 @@ static inline void __init check_timer(void)
         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);
@@ -2928,8 +2930,17 @@ static inline void __init check_timer(void)
                 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();
@@ -2943,6 +2954,7 @@ static inline void __init check_timer(void)
                 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: "
@@ -2957,7 +2969,6 @@ static inline void __init check_timer(void)
                  */
                 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");
@@ -2972,6 +2983,7 @@ static inline void __init check_timer(void)
                 /*
                  * 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");
@@ -2997,6 +3009,7 @@ static inline void __init check_timer(void)
                 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");
@@ -3014,6 +3027,7 @@ static inline void __init check_timer(void)
                 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");