diff options
Diffstat (limited to 'arch/x86/kernel/apic_64.c')
-rw-r--r-- | arch/x86/kernel/apic_64.c | 48 |
1 files changed, 38 insertions, 10 deletions
diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c index 13dea935b4e..46523c0cc6f 100644 --- a/arch/x86/kernel/apic_64.c +++ b/arch/x86/kernel/apic_64.c @@ -81,6 +81,9 @@ static void lapic_timer_setup(enum clock_event_mode mode, static void lapic_timer_broadcast(cpumask_t mask); static void apic_pm_activate(void); +/* + * The local apic timer can be used for any function which is CPU local. + */ static struct clock_event_device lapic_clockevent = { .name = "lapic", .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT @@ -127,6 +130,11 @@ static int modern_apic(void) return lapic_get_version() >= 0x14; } +/* + * Paravirt kernels also might be using these below ops. So we still + * use generic apic_read()/apic_write(), which might be pointing to different + * ops in PARAVIRT case. + */ void xapic_wait_icr_idle(void) { while (apic_read(APIC_ICR) & APIC_ICR_BUSY) @@ -175,7 +183,6 @@ static struct apic_ops xapic_ops = { }; struct apic_ops __read_mostly *apic_ops = &xapic_ops; - EXPORT_SYMBOL_GPL(apic_ops); static void x2apic_wait_icr_idle(void) @@ -244,6 +251,10 @@ int lapic_get_maxlvt(void) return APIC_INTEGRATED(GET_APIC_VERSION(v)) ? GET_APIC_MAXLVT(v) : 2; } +/* + * Local APIC timer + */ + /* Clock divisor is set to 1 */ #define APIC_DIVISOR 1 @@ -257,7 +268,6 @@ int lapic_get_maxlvt(void) * We do reads before writes even if unnecessary, to get around the * P5 APIC double write bug. */ - static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen) { unsigned int lvtt_value, tmp_value; @@ -474,10 +484,10 @@ static int __init calibrate_APIC_clock(void) void __init setup_boot_APIC_clock(void) { /* - * The local apic timer can be disabled via the kernel commandline. - * Register the lapic timer as a dummy clock event source on SMP - * systems, so the broadcast mechanism is used. On UP systems simply - * ignore it. + * The local apic timer can be disabled via the kernel + * commandline or from the CPU detection code. Register the lapic + * timer as a dummy clock event source on SMP systems, so the + * broadcast mechanism is used. On UP systems simply ignore it. */ if (disable_apic_timer) { printk(KERN_INFO "Disabling APIC timer\n"); @@ -489,7 +499,9 @@ void __init setup_boot_APIC_clock(void) return; } - printk(KERN_INFO "Using local APIC timer interrupts.\n"); + apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n" + "calibrating APIC timer ...\n"); + if (calibrate_APIC_clock()) { /* No broadcast on UP ! */ if (num_possible_cpus() > 1) @@ -508,6 +520,7 @@ void __init setup_boot_APIC_clock(void) printk(KERN_WARNING "APIC timer registered as dummy," " due to nmi_watchdog=%d!\n", nmi_watchdog); + /* Setup the lapic or request the broadcast */ setup_APIC_timer(); } @@ -577,6 +590,7 @@ void smp_apic_timer_interrupt(struct pt_regs *regs) irq_enter(); local_apic_timer_interrupt(); irq_exit(); + set_irq_regs(old_regs); } @@ -1248,6 +1262,13 @@ void __init connect_bsp_APIC(void) enable_apic_mode(); } +/** + * disconnect_bsp_APIC - detach the APIC from the interrupt system + * @virt_wire_setup: indicates, whether virtual wire mode is selected + * + * Virtual wire mode is necessary to deliver legacy interrupts even when the + * APIC is disabled. + */ void disconnect_bsp_APIC(int virt_wire_setup) { /* Go back to Virtual Wire compatibility mode */ @@ -1347,9 +1368,11 @@ int hard_smp_processor_id(void) #ifdef CONFIG_PM static struct { - /* 'active' is true if the local APIC was enabled by us and - not the BIOS; this signifies that we are also responsible - for disabling it before entering apm/acpi suspend */ + /* + * 'active' is true if the local APIC was enabled by us and + * not the BIOS; this signifies that we are also responsible + * for disabling it before entering apm/acpi suspend + */ int active; /* r/w apic fields */ unsigned int apic_id; @@ -1458,6 +1481,11 @@ static int lapic_resume(struct sys_device *dev) return 0; } +/* + * This device has no shutdown method - fully functioning local APICs + * are needed on every CPU up until machine_halt/restart/poweroff. + */ + static struct sysdev_class lapic_sysclass = { .name = "lapic", .resume = lapic_resume, |