Messages in this thread Patch in this message | | | Date | Sun, 07 Sep 2008 11:13:38 +0200 | From | Manfred Spraul <> | Subject | ia64 start secondary cpus: what's the first line where interrupts can arrive? |
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Hi,
For my rcu implementation, I try to figure out how the boot process for secondary cpus works.
arch/ia64/kernel/smpboot.c contains the following code: > static void __cpuinit > smp_callin (void) > { > [snip] > per_cpu(cpu_state, cpuid) = CPU_ONLINE; > spin_unlock(&vector_lock); > ipi_call_unlock_irq(); > <<<<< > <<<<< ipi_call_unlock_irq() does local_irq_enable() > <<<<< > smp_setup_percpu_timer(); > > ia64_mca_cmc_vector_setup(); /* Setup vector on AP */ > > #ifdef CONFIG_PERFMON > pfm_init_percpu(); > #endif > > local_irq_enable(); > <<<<< > <<<<< Another local_irq_enable(). > <<<<< Which of these two local_irq_enable()'s is the right one?
And: IMHO it's unclean to abuse ipi_call_unlock_irq() to enable the local interrupts. What about the attached patch? Untested due to lack of test hardware.
-- Manfred diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c index 03f1a99..f4868d2 100644 --- a/arch/ia64/kernel/smpboot.c +++ b/arch/ia64/kernel/smpboot.c @@ -396,14 +396,17 @@ smp_callin (void) fix_b0_for_bsp(); - ipi_call_lock_irq(); + ipi_call_lock(); spin_lock(&vector_lock); /* Setup the per cpu irq handling data structures */ __setup_vector_irq(cpuid); cpu_set(cpuid, cpu_online_map); per_cpu(cpu_state, cpuid) = CPU_ONLINE; spin_unlock(&vector_lock); - ipi_call_unlock_irq(); + ipi_call_unlock(); + + /* begin processing interrupts */ + local_irq_enable(); smp_setup_percpu_timer(); @@ -413,8 +416,6 @@ smp_callin (void) pfm_init_percpu(); #endif - local_irq_enable(); - if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { /* * Synchronize the ITC with the BP. Need to do this after irqs are | |