From d4d25deca49ec2527a634557bf5a6cf449f85deb Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Mon, 26 Nov 2007 20:42:19 +0100 Subject: [PATCH] x86: fix NMI watchdog & 'stopped time' problem More than 3 years ago Niclas Gustafsson reported a 'stopped time' problem: > Watching the /proc/interrupts with 10s apart after the "stop". > > [root@s151 root]# more /proc/interrupts > CPU0 > 0: 66413955 local-APIC-edge timer [...] > LOC: 67355837 > ERR: 0 > MIS: 0 > [root@s151 root]# more /proc/interrupts > CPU0 > 0: 66413955 local-APIC-edge timer [...] > LOC: 67379568 > ERR: 0 > MIS: 0 This may be because buggy SMM firmware messes with the 8259A (configured for a transparent mode -- yes that rare "local-APIC-edge" mode is tricky ;-) ) insanely. this should resolve: http://bugzilla.kernel.org/show_bug.cgi?id=2544 http://bugzilla.kernel.org/show_bug.cgi?id=6296 Patch-dusted-off-by: Ingo Molnar Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/io_apic_32.c | 12 ++++++++++-- arch/x86/kernel/nmi_32.c | 9 +++++++-- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c index f35c6eb33da9..fc4bbc1d1331 100644 --- a/arch/x86/kernel/io_apic_32.c +++ b/arch/x86/kernel/io_apic_32.c @@ -2166,6 +2166,10 @@ static inline void __init check_timer(void) { int apic1, pin1, apic2, pin2; int vector; + unsigned int ver; + + ver = apic_read(APIC_LVR); + ver = GET_APIC_VERSION(ver); /* * get/set the timer IRQ vector: @@ -2179,11 +2183,15 @@ static inline void __init check_timer(void) * mode for the 8259A whenever interrupts are routed * through I/O APICs. Also IRQ0 has to be enabled in * the 8259A which implies the virtual wire has to be - * disabled in the local APIC. + * disabled in the local APIC. Finally timer interrupts + * need to be acknowledged manually in the 8259A for + * timer_interrupt() and for the i82489DX when using + * the NMI watchdog. */ apic_write_around(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT); init_8259A(1); - timer_ack = 1; + timer_ack = !cpu_has_tsc; + timer_ack |= (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver)); if (timer_over_8254 > 0) enable_8259A_irq(0); diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c index 600fd404e440..f5cc47c60b13 100644 --- a/arch/x86/kernel/nmi_32.c +++ b/arch/x86/kernel/nmi_32.c @@ -25,6 +25,7 @@ #include #include +#include #include "mach_traps.h" @@ -83,7 +84,7 @@ static int __init check_nmi_watchdog(void) prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL); if (!prev_nmi_count) - return -1; + goto error; printk(KERN_INFO "Testing NMI watchdog ... "); @@ -117,7 +118,7 @@ static int __init check_nmi_watchdog(void) if (!atomic_read(&nmi_active)) { kfree(prev_nmi_count); atomic_set(&nmi_active, -1); - return -1; + goto error; } printk("OK.\n"); @@ -128,6 +129,10 @@ static int __init check_nmi_watchdog(void) kfree(prev_nmi_count); return 0; +error: + timer_ack = !cpu_has_tsc; + + return -1; } /* This needs to happen later in boot so counters are working */ late_initcall(check_nmi_watchdog);