diff options
| author | Cyrill Gorcunov <gorcunov@openvz.org> | 2009-04-12 20:47:41 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-12 19:23:53 +0200 |
| commit | 08306ce61d6848e6fbf74fa4cc693c3fb29e943f (patch) | |
| tree | f61e7f9061e5fa11447b5ab7fd473bfe8985bb99 /arch/x86/kernel | |
| parent | c0eaa4536f08b98fbcfa7fce5b7b0de1bebcb0e1 (diff) | |
x86: apic - introduce dummy apic operations
Impact: refactor, speed up and robustize code
In case if apic was disabled by kernel option
or by hardware limits we can use dummy operations
in apic->write to simplify the ack_APIC_irq() code.
At the lame time the patch fixes the missed EOI in
do_IRQ function (which has place if kernel is compiled
as X86-32 and interrupt without handler happens where
apic was not asked to be disabled via kernel option).
Note that native_apic_write_dummy() consists of
WARN_ON_ONCE to catch any buggy writes on enabled
APICs. Could be removed after some time of testing.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.724788431@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 24 | ||||
| -rw-r--r-- | arch/x86/kernel/irq.c | 10 |
2 files changed, 26 insertions, 8 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index c3be10f5773..9b849d4957d 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -232,6 +232,24 @@ static int modern_apic(void) return lapic_get_version() >= 0x14; } +/* + * bare function to substitute write operation + * and it's _that_ fast :) + */ +void native_apic_write_dummy(u32 reg, u32 v) +{ + WARN_ON_ONCE((cpu_has_apic || !disable_apic)); +} + +/* + * right after this call apic->write doesn't do anything + * note that there is no restore operation it works one way + */ +void apic_disable(void) +{ + apic->write = native_apic_write_dummy; +} + void native_apic_wait_icr_idle(void) { while (apic_read(APIC_ICR) & APIC_ICR_BUSY) @@ -1582,6 +1600,12 @@ void __init init_apic_mappings(void) */ if (boot_cpu_physical_apicid == -1U) boot_cpu_physical_apicid = read_apic_id(); + + /* lets check if we may to NOP'ify apic operations */ + if (!cpu_has_apic) { + pr_info("APIC: disable apic facility\n"); + apic_disable(); + } } /* diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 6603492e8b7..fd57bf35d0f 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -27,7 +27,6 @@ void ack_bad_irq(unsigned int irq) if (printk_ratelimit()) pr_err("unexpected IRQ trap at vector %02x\n", irq); -#ifdef CONFIG_X86_LOCAL_APIC /* * Currently unexpected vectors happen only on SMP and APIC. * We _must_ ack these because every local APIC has only N @@ -37,9 +36,7 @@ void ack_bad_irq(unsigned int irq) * completely. * But only ack when the APIC is enabled -AK */ - if (cpu_has_apic) - ack_APIC_irq(); -#endif + ack_APIC_irq(); } #define irq_stats(x) (&per_cpu(irq_stat, x)) @@ -214,10 +211,7 @@ unsigned int __irq_entry do_IRQ(struct pt_regs *regs) irq = __get_cpu_var(vector_irq)[vector]; if (!handle_irq(irq, regs)) { -#ifdef CONFIG_X86_64 - if (!disable_apic) - ack_APIC_irq(); -#endif + ack_APIC_irq(); if (printk_ratelimit()) pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n", |