[patch 5/8] Add SMP support on i386 to reservation framework

From: dzickus
Date: Tue May 09 2006 - 16:58:43 EST


This patch includes the changes to make the nmi watchdog on i386 SMP aware.
A bunch of code was moved around to make it simpler to read. In addition,
it is now possible to determine if a particular NMI was the result of the
watchdog or not. This feature allows the kernel to filter out unknown NMIs
easier.

Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx>

Index: linux-don/arch/i386/kernel/apic.c
===================================================================
--- linux-don.orig/arch/i386/kernel/apic.c
+++ linux-don/arch/i386/kernel/apic.c
@@ -587,8 +587,7 @@ void __devinit setup_local_APIC(void)
printk("No ESR for 82489DX.\n");
}

- if (nmi_watchdog == NMI_LOCAL_APIC)
- setup_apic_nmi_watchdog();
+ setup_apic_nmi_watchdog(NULL);
apic_pm_activate();
}

Index: linux-don/arch/i386/kernel/nmi.c
===================================================================
--- linux-don.orig/arch/i386/kernel/nmi.c
+++ linux-don/arch/i386/kernel/nmi.c
@@ -24,16 +24,10 @@

#include <asm/smp.h>
#include <asm/nmi.h>
+#include <asm/kdebug.h>

#include "mach_traps.h"

-unsigned int nmi_watchdog = NMI_NONE;
-extern int unknown_nmi_panic;
-static unsigned int nmi_hz = HZ;
-static unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */
-static unsigned int nmi_p4_cccr_val;
-extern void show_registers(struct pt_regs *regs);
-
/* perfctr_nmi_owner tracks the ownership of the perfctr registers:
* evtsel_nmi_owner tracks the ownership of the event selection
* - different performance counters/ event selection may be reserved for
@@ -63,51 +57,31 @@ static unsigned int lapic_nmi_owner;
#define LAPIC_NMI_RESERVED (1<<1)

/* nmi_active:
- * +1: the lapic NMI watchdog is active, but can be disabled
- * 0: the lapic NMI watchdog has not been set up, and cannot
+ * >0: the lapic NMI watchdog is active, but can be disabled
+ * <0: the lapic NMI watchdog has not been set up, and cannot
* be enabled
- * -1: the lapic NMI watchdog is disabled, but can be enabled
+ * 0: the lapic NMI watchdog is disabled, but can be enabled
*/
-int nmi_active;
+atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */

-#define K7_EVNTSEL_ENABLE (1 << 22)
-#define K7_EVNTSEL_INT (1 << 20)
-#define K7_EVNTSEL_OS (1 << 17)
-#define K7_EVNTSEL_USR (1 << 16)
-#define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING 0x76
-#define K7_NMI_EVENT K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
+unsigned int nmi_watchdog = NMI_DEFAULT;
+static unsigned int nmi_hz = HZ;

-#define P6_EVNTSEL0_ENABLE (1 << 22)
-#define P6_EVNTSEL_INT (1 << 20)
-#define P6_EVNTSEL_OS (1 << 17)
-#define P6_EVNTSEL_USR (1 << 16)
-#define P6_EVENT_CPU_CLOCKS_NOT_HALTED 0x79
-#define P6_NMI_EVENT P6_EVENT_CPU_CLOCKS_NOT_HALTED
+struct nmi_watchdog_ctlblk {
+ int enabled;
+ u64 check_bit;
+ unsigned int cccr_msr;
+ unsigned int perfctr_msr; /* the MSR to reset in NMI handler */
+ unsigned int evntsel_msr; /* the MSR to select the events to handle */
+};
+static DEFINE_PER_CPU(struct nmi_watchdog_ctlblk, nmi_watchdog_ctlblk);

-#define MSR_P4_MISC_ENABLE 0x1A0
-#define MSR_P4_MISC_ENABLE_PERF_AVAIL (1<<7)
-#define MSR_P4_MISC_ENABLE_PEBS_UNAVAIL (1<<12)
-#define MSR_P4_PERFCTR0 0x300
-#define MSR_P4_CCCR0 0x360
-#define P4_ESCR_EVENT_SELECT(N) ((N)<<25)
-#define P4_ESCR_OS (1<<3)
-#define P4_ESCR_USR (1<<2)
-#define P4_CCCR_OVF_PMI0 (1<<26)
-#define P4_CCCR_OVF_PMI1 (1<<27)
-#define P4_CCCR_THRESHOLD(N) ((N)<<20)
-#define P4_CCCR_COMPLEMENT (1<<19)
-#define P4_CCCR_COMPARE (1<<18)
-#define P4_CCCR_REQUIRED (3<<16)
-#define P4_CCCR_ESCR_SELECT(N) ((N)<<13)
-#define P4_CCCR_ENABLE (1<<12)
-/* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
- CRU_ESCR0 (with any non-null event selector) through a complemented
- max threshold. [IA32-Vol3, Section 14.9.9] */
-#define MSR_P4_IQ_COUNTER0 0x30C
-#define P4_NMI_CRU_ESCR0 (P4_ESCR_EVENT_SELECT(0x3F)|P4_ESCR_OS|P4_ESCR_USR)
-#define P4_NMI_IQ_CCCR0 \
- (P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT| \
- P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE)
+/* local prototypes */
+static void stop_apic_nmi_watchdog(void *unused);
+static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);
+
+extern void show_registers(struct pt_regs *regs);
+extern int unknown_nmi_panic;

/* converts an msr to an appropriate reservation bit */
static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
@@ -208,6 +182,17 @@ void release_evntsel_nmi(unsigned int ms
clear_bit(counter, &__get_cpu_var(evntsel_nmi_owner[0]));
}

+static __cpuinit inline int nmi_known_cpu(void)
+{
+ switch (boot_cpu_data.x86_vendor) {
+ case X86_VENDOR_AMD:
+ return ((boot_cpu_data.x86 == 15) || (boot_cpu_data.x86 == 6));
+ case X86_VENDOR_INTEL:
+ return ((boot_cpu_data.x86 == 15) || (boot_cpu_data.x86 == 6));
+ }
+ return 0;
+}
+
#ifdef CONFIG_SMP
/* The performance counters used by NMI_LOCAL_APIC don't trigger when
* the CPU is idle. To make sure the NMI watchdog really ticks on all
@@ -234,7 +219,10 @@ static int __init check_nmi_watchdog(voi
unsigned int *prev_nmi_count;
int cpu;

- if (nmi_watchdog == NMI_NONE)
+ if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT))
+ return 0;
+
+ if (!atomic_read(&nmi_active))
return 0;

prev_nmi_count = kmalloc(NR_CPUS * sizeof(int), GFP_KERNEL);
@@ -258,18 +246,22 @@ static int __init check_nmi_watchdog(voi
if (!cpu_isset(cpu, cpu_callin_map))
continue;
#endif
+ if (!per_cpu(nmi_watchdog_ctlblk.enabled, cpu))
+ continue;
if (nmi_count(cpu) - prev_nmi_count[cpu] <= 5) {
- endflag = 1;
printk("CPU#%d: NMI appears to be stuck (%d->%d)!\n",
cpu,
prev_nmi_count[cpu],
nmi_count(cpu));
- nmi_active = 0;
- lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG;
- kfree(prev_nmi_count);
- return -1;
+ per_cpu(nmi_watchdog_ctlblk.enabled, cpu) = 0;
+ atomic_dec(&nmi_active);
}
}
+ if (!atomic_read(&nmi_active)) {
+ kfree(prev_nmi_count);
+ atomic_set(&nmi_active, -1);
+ return -1;
+ }
endflag = 1;
printk("OK.\n");

@@ -290,31 +282,16 @@ static int __init setup_nmi_watchdog(cha

get_option(&str, &nmi);

- if (nmi >= NMI_INVALID)
+ if ((nmi >= NMI_INVALID) || (nmi < NMI_NONE))
return 0;
- if (nmi == NMI_NONE)
- nmi_watchdog = nmi;
/*
* If any other x86 CPU has a local APIC, then
* please test the NMI stuff there and send me the
* missing bits. Right now Intel P6/P4 and AMD K7 only.
*/
- if ((nmi == NMI_LOCAL_APIC) &&
- (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
- (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15))
- nmi_watchdog = nmi;
- if ((nmi == NMI_LOCAL_APIC) &&
- (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&
- (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15))
- nmi_watchdog = nmi;
- /*
- * We can enable the IO-APIC watchdog
- * unconditionally.
- */
- if (nmi == NMI_IO_APIC) {
- nmi_active = 1;
- nmi_watchdog = nmi;
- }
+ if ((nmi == NMI_LOCAL_APIC) && (nmi_known_cpu() == 0))
+ return 0; /* no lapic support */
+ nmi_watchdog = nmi;
return 1;
}

@@ -322,41 +299,30 @@ __setup("nmi_watchdog=", setup_nmi_watch

static void disable_lapic_nmi_watchdog(void)
{
- if (nmi_active <= 0)
+ BUG_ON(nmi_watchdog != NMI_LOCAL_APIC);
+
+ if (atomic_read(&nmi_active) <= 0)
return;
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_AMD:
- wrmsr(MSR_K7_EVNTSEL0, 0, 0);
- break;
- case X86_VENDOR_INTEL:
- switch (boot_cpu_data.x86) {
- case 6:
- if (boot_cpu_data.x86_model > 0xd)
- break;

- wrmsr(MSR_P6_EVNTSEL0, 0, 0);
- break;
- case 15:
- if (boot_cpu_data.x86_model > 0x4)
- break;
+ on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1);

- wrmsr(MSR_P4_IQ_CCCR0, 0, 0);
- wrmsr(MSR_P4_CRU_ESCR0, 0, 0);
- break;
- }
- break;
- }
- nmi_active = -1;
- /* tell do_nmi() and others that we're not active any more */
- nmi_watchdog = 0;
+ BUG_ON(atomic_read(&nmi_active) != 0);
}

static void enable_lapic_nmi_watchdog(void)
{
- if (nmi_active < 0) {
- nmi_watchdog = NMI_LOCAL_APIC;
- setup_apic_nmi_watchdog();
- }
+ BUG_ON(nmi_watchdog != NMI_LOCAL_APIC);
+
+ /* are we already enabled */
+ if (atomic_read(&nmi_active) != 0)
+ return;
+
+ /* are we lapic aware */
+ if (nmi_known_cpu() <= 0)
+ return;
+
+ on_each_cpu(setup_apic_nmi_watchdog, NULL, 0, 1);
+ touch_nmi_watchdog();
}

int reserve_lapic_nmi(void)
@@ -388,20 +354,25 @@ void release_lapic_nmi(void)

void disable_timer_nmi_watchdog(void)
{
- if ((nmi_watchdog != NMI_IO_APIC) || (nmi_active <= 0))
+ BUG_ON(nmi_watchdog != NMI_IO_APIC);
+
+ if (atomic_read(&nmi_active) <= 0)
return;

- unset_nmi_callback();
- nmi_active = -1;
- nmi_watchdog = NMI_NONE;
+ disable_irq(0);
+ on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1);
+
+ BUG_ON(atomic_read(&nmi_active) != 0);
}

void enable_timer_nmi_watchdog(void)
{
- if (nmi_active < 0) {
- nmi_watchdog = NMI_IO_APIC;
+ BUG_ON(nmi_watchdog != NMI_IO_APIC);
+
+ if (atomic_read(&nmi_active) == 0) {
touch_nmi_watchdog();
- nmi_active = 1;
+ on_each_cpu(setup_apic_nmi_watchdog, NULL, 0, 1);
+ enable_irq(0);
}
}

@@ -411,7 +382,7 @@ static int nmi_pm_active; /* nmi_active

static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)
{
- nmi_pm_active = nmi_active;
+ nmi_pm_active = atomic_read(&nmi_active);
disable_lapic_nmi_watchdog();
return 0;
}
@@ -439,7 +410,13 @@ static int __init init_lapic_nmi_sysfs(v
{
int error;

- if (nmi_active == 0 || nmi_watchdog != NMI_LOCAL_APIC)
+ /* should really be a BUG_ON but b/c this is an
+ * init call, it just doesn't work. -dcz
+ */
+ if (nmi_watchdog != NMI_LOCAL_APIC)
+ return 0;
+
+ if ( atomic_read(&nmi_active) < 0 )
return 0;

error = sysdev_class_register(&nmi_sysclass);
@@ -457,143 +434,312 @@ late_initcall(init_lapic_nmi_sysfs);
* Original code written by Keith Owens.
*/

-static void write_watchdog_counter(const char *descr)
+static void write_watchdog_counter(unsigned int perfctr_msr, const char *descr)
{
u64 count = (u64)cpu_khz * 1000;

do_div(count, nmi_hz);
if(descr)
Dprintk("setting %s to -0x%08Lx\n", descr, count);
- wrmsrl(nmi_perfctr_msr, 0 - count);
+ wrmsrl(perfctr_msr, 0 - count);
}

+/* Note that these events don't tick when the CPU idles. This means
+ the frequency varies with CPU load. */
+
+#define K7_EVNTSEL_ENABLE (1 << 22)
+#define K7_EVNTSEL_INT (1 << 20)
+#define K7_EVNTSEL_OS (1 << 17)
+#define K7_EVNTSEL_USR (1 << 16)
+#define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING 0x76
+#define K7_NMI_EVENT K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
+
static int setup_k7_watchdog(void)
{
+ unsigned int perfctr_msr, evntsel_msr;
unsigned int evntsel;
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);

- nmi_perfctr_msr = MSR_K7_PERFCTR0;
-
- if (!reserve_perfctr_nmi(nmi_perfctr_msr))
+ perfctr_msr = MSR_K7_PERFCTR0;
+ evntsel_msr = MSR_K7_EVNTSEL0;
+ if (!reserve_perfctr_nmi(perfctr_msr))
goto fail;

- if (!reserve_evntsel_nmi(MSR_K7_EVNTSEL0))
+ if (!reserve_evntsel_nmi(evntsel_msr))
goto fail1;

- wrmsrl(MSR_K7_PERFCTR0, 0UL);
+ wrmsrl(perfctr_msr, 0UL);

evntsel = K7_EVNTSEL_INT
| K7_EVNTSEL_OS
| K7_EVNTSEL_USR
| K7_NMI_EVENT;

- wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
- write_watchdog_counter("K7_PERFCTR0");
+ /* setup the timer */
+ wrmsr(evntsel_msr, evntsel, 0);
+ write_watchdog_counter(perfctr_msr, "K7_PERFCTR0");
apic_write(APIC_LVTPC, APIC_DM_NMI);
evntsel |= K7_EVNTSEL_ENABLE;
- wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
+ wrmsr(evntsel_msr, evntsel, 0);
+
+ wd->perfctr_msr = perfctr_msr;
+ wd->evntsel_msr = evntsel_msr;
+ wd->cccr_msr = 0; //unused
+ wd->check_bit = 1ULL<<63;
return 1;
fail1:
- release_perfctr_nmi(nmi_perfctr_msr);
+ release_perfctr_nmi(perfctr_msr);
fail:
return 0;
}

+static void stop_k7_watchdog(void)
+{
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
+
+ wrmsr(wd->evntsel_msr, 0, 0);
+
+ release_evntsel_nmi(wd->evntsel_msr);
+ release_perfctr_nmi(wd->perfctr_msr);
+}
+
+#define P6_EVNTSEL0_ENABLE (1 << 22)
+#define P6_EVNTSEL_INT (1 << 20)
+#define P6_EVNTSEL_OS (1 << 17)
+#define P6_EVNTSEL_USR (1 << 16)
+#define P6_EVENT_CPU_CLOCKS_NOT_HALTED 0x79
+#define P6_NMI_EVENT P6_EVENT_CPU_CLOCKS_NOT_HALTED
+
static int setup_p6_watchdog(void)
{
+ unsigned int perfctr_msr, evntsel_msr;
unsigned int evntsel;
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);

- nmi_perfctr_msr = MSR_P6_PERFCTR0;
-
- if (!reserve_perfctr_nmi(nmi_perfctr_msr))
+ perfctr_msr = MSR_P6_PERFCTR0;
+ evntsel_msr = MSR_P6_EVNTSEL0;
+ if (!reserve_perfctr_nmi(perfctr_msr))
goto fail;

- if (!reserve_evntsel_nmi(MSR_P6_EVNTSEL0))
+ if (!reserve_evntsel_nmi(evntsel_msr))
goto fail1;

+ wrmsrl(perfctr_msr, 0UL);
+
evntsel = P6_EVNTSEL_INT
| P6_EVNTSEL_OS
| P6_EVNTSEL_USR
| P6_NMI_EVENT;

- wrmsr(MSR_P6_EVNTSEL0, evntsel, 0);
- write_watchdog_counter("P6_PERFCTR0");
+ /* setup the timer */
+ wrmsr(evntsel_msr, evntsel, 0);
+ write_watchdog_counter(perfctr_msr, "P6_PERFCTR0");
apic_write(APIC_LVTPC, APIC_DM_NMI);
- evntsel |= P6_EVNTSEL0_ENABLE;
- wrmsr(MSR_P6_EVNTSEL0, evntsel, 0);
+ evntsel |= K7_EVNTSEL_ENABLE;
+ wrmsr(evntsel_msr, evntsel, 0);
+
+ wd->perfctr_msr = perfctr_msr;
+ wd->evntsel_msr = evntsel_msr;
+ wd->cccr_msr = 0; //unused
+ wd->check_bit = 1ULL<<39;
return 1;
fail1:
- release_perfctr_nmi(nmi_perfctr_msr);
+ release_perfctr_nmi(perfctr_msr);
fail:
return 0;
}

+static void stop_p6_watchdog(void)
+{
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
+
+ wrmsr(wd->evntsel_msr, 0, 0);
+
+ release_evntsel_nmi(wd->evntsel_msr);
+ release_perfctr_nmi(wd->perfctr_msr);
+}
+
+/* Note that these events don't tick when the CPU idles. This means
+ the frequency varies with CPU load. */
+
+#define MSR_P4_MISC_ENABLE_PERF_AVAIL (1<<7)
+#define P4_ESCR_EVENT_SELECT(N) ((N)<<25)
+#define P4_ESCR_OS (1<<3)
+#define P4_ESCR_USR (1<<2)
+#define P4_CCCR_OVF_PMI0 (1<<26)
+#define P4_CCCR_OVF_PMI1 (1<<27)
+#define P4_CCCR_THRESHOLD(N) ((N)<<20)
+#define P4_CCCR_COMPLEMENT (1<<19)
+#define P4_CCCR_COMPARE (1<<18)
+#define P4_CCCR_REQUIRED (3<<16)
+#define P4_CCCR_ESCR_SELECT(N) ((N)<<13)
+#define P4_CCCR_ENABLE (1<<12)
+#define P4_CCCR_OVF (1<<31)
+/* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
+ CRU_ESCR0 (with any non-null event selector) through a complemented
+ max threshold. [IA32-Vol3, Section 14.9.9] */
+
static int setup_p4_watchdog(void)
{
+ unsigned int perfctr_msr, evntsel_msr, cccr_msr;
+ unsigned int evntsel, cccr_val;
unsigned int misc_enable, dummy;
+ unsigned int ht_num;
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);

- rdmsr(MSR_P4_MISC_ENABLE, misc_enable, dummy);
+ rdmsr(MSR_IA32_MISC_ENABLE, misc_enable, dummy);
if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL))
return 0;

- nmi_perfctr_msr = MSR_P4_IQ_COUNTER0;
- nmi_p4_cccr_val = P4_NMI_IQ_CCCR0;
#ifdef CONFIG_SMP
- if (smp_num_siblings == 2)
- nmi_p4_cccr_val |= P4_CCCR_OVF_PMI1;
+ /* detect which hyperthread we are on */
+ if (smp_num_siblings == 2) {
+ unsigned int ebx, apicid;
+
+ ebx = cpuid_ebx(1);
+ apicid = (ebx >> 24) & 0xff;
+ ht_num = apicid & 1;
+ } else
#endif
+ ht_num = 0;

- if (!reserve_perfctr_nmi(nmi_perfctr_msr))
+ /* performance counters are shared resources
+ * assign each hyperthread its own set
+ * (re-use the ESCR0 register, seems safe
+ * and keeps the cccr_val the same)
+ */
+ if (!ht_num) {
+ /* logical cpu 0 */
+ perfctr_msr = MSR_P4_IQ_PERFCTR0;
+ evntsel_msr = MSR_P4_CRU_ESCR0;
+ cccr_msr = MSR_P4_IQ_CCCR0;
+ cccr_val = P4_CCCR_OVF_PMI0 | P4_CCCR_ESCR_SELECT(4);
+ } else {
+ /* logical cpu 1 */
+ perfctr_msr = MSR_P4_IQ_PERFCTR1;
+ evntsel_msr = MSR_P4_CRU_ESCR0;
+ cccr_msr = MSR_P4_IQ_CCCR1;
+ cccr_val = P4_CCCR_OVF_PMI1 | P4_CCCR_ESCR_SELECT(4);
+ }
+
+ if (!reserve_perfctr_nmi(perfctr_msr))
goto fail;

- if (!reserve_evntsel_nmi(MSR_P4_CRU_ESCR0))
+ if (!reserve_evntsel_nmi(evntsel_msr))
goto fail1;

- wrmsr(MSR_P4_CRU_ESCR0, P4_NMI_CRU_ESCR0, 0);
- wrmsr(MSR_P4_IQ_CCCR0, P4_NMI_IQ_CCCR0 & ~P4_CCCR_ENABLE, 0);
- write_watchdog_counter("P4_IQ_COUNTER0");
+ evntsel = P4_ESCR_EVENT_SELECT(0x3F)
+ | P4_ESCR_OS
+ | P4_ESCR_USR;
+
+ cccr_val |= P4_CCCR_THRESHOLD(15)
+ | P4_CCCR_COMPLEMENT
+ | P4_CCCR_COMPARE
+ | P4_CCCR_REQUIRED;
+
+ wrmsr(evntsel_msr, evntsel, 0);
+ wrmsr(cccr_msr, cccr_val, 0);
+ write_watchdog_counter(perfctr_msr, "P4_IQ_COUNTER0");
apic_write(APIC_LVTPC, APIC_DM_NMI);
- wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
+ cccr_val |= P4_CCCR_ENABLE;
+ wrmsr(cccr_msr, cccr_val, 0);
+ wd->perfctr_msr = perfctr_msr;
+ wd->evntsel_msr = evntsel_msr;
+ wd->cccr_msr = cccr_msr;
+ wd->check_bit = 1ULL<<39;
return 1;
fail1:
- release_perfctr_nmi(nmi_perfctr_msr);
+ release_perfctr_nmi(perfctr_msr);
fail:
return 0;
}

-void setup_apic_nmi_watchdog (void)
+static void stop_p4_watchdog(void)
{
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_AMD:
- if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15)
- return;
- if (!setup_k7_watchdog())
- return;
- break;
- case X86_VENDOR_INTEL:
- switch (boot_cpu_data.x86) {
- case 6:
- if (boot_cpu_data.x86_model > 0xd)
- return;
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
+
+ wrmsr(wd->cccr_msr, 0, 0);
+ wrmsr(wd->evntsel_msr, 0, 0);
+
+ release_evntsel_nmi(wd->evntsel_msr);
+ release_perfctr_nmi(wd->perfctr_msr);
+}
+
+void setup_apic_nmi_watchdog (void *unused)
+{
+ /* only support LOCAL and IO APICs for now */
+ if ((nmi_watchdog != NMI_LOCAL_APIC) &&
+ (nmi_watchdog != NMI_IO_APIC))
+ return;

- if(!setup_p6_watchdog())
+ if (nmi_watchdog == NMI_LOCAL_APIC) {
+ switch (boot_cpu_data.x86_vendor) {
+ case X86_VENDOR_AMD:
+ if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15)
return;
- break;
- case 15:
- if (boot_cpu_data.x86_model > 0x4)
+ if (!setup_k7_watchdog())
return;
+ break;
+ case X86_VENDOR_INTEL:
+ switch (boot_cpu_data.x86) {
+ case 6:
+ if (boot_cpu_data.x86_model > 0xd)
+ return;

- if (!setup_p4_watchdog())
+ if (!setup_p6_watchdog())
+ return;
+ break;
+ case 15:
+ if (boot_cpu_data.x86_model > 0x4)
+ return;
+
+ if (!setup_p4_watchdog())
+ return;
+ break;
+ default:
return;
+ }
+ break;
+ default:
+ return;
+ }
+ }
+ __get_cpu_var(nmi_watchdog_ctlblk.enabled) = 1;
+ atomic_inc(&nmi_active);
+}
+
+static void stop_apic_nmi_watchdog(void *unused)
+{
+ /* only support LOCAL and IO APICs for now */
+ if ((nmi_watchdog != NMI_LOCAL_APIC) &&
+ (nmi_watchdog != NMI_IO_APIC))
+ return;
+
+ if (nmi_watchdog == NMI_LOCAL_APIC) {
+ switch (boot_cpu_data.x86_vendor) {
+ case X86_VENDOR_AMD:
+ stop_k7_watchdog();
+ break;
+ case X86_VENDOR_INTEL:
+ switch (boot_cpu_data.x86) {
+ case 6:
+ if (boot_cpu_data.x86_model > 0xd)
+ break;
+ stop_p6_watchdog();
+ break;
+ case 15:
+ if (boot_cpu_data.x86_model > 0x4)
+ break;
+ stop_p4_watchdog();
+ break;
+ }
break;
default:
return;
}
- break;
- default:
- return;
}
- lapic_nmi_owner = LAPIC_NMI_WATCHDOG;
- nmi_active = 1;
+ __get_cpu_var(nmi_watchdog_ctlblk.enabled) = 0;
+ atomic_dec(&nmi_active);
}

/*
@@ -634,7 +780,7 @@ void touch_nmi_watchdog (void)

extern void die_nmi(struct pt_regs *, const char *msg);

-void nmi_watchdog_tick (struct pt_regs * regs)
+void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
{

/*
@@ -643,11 +789,21 @@ void nmi_watchdog_tick (struct pt_regs *
* smp_processor_id().
*/
unsigned int sum;
+ int touched = 0;
int cpu = smp_processor_id();
+ struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
+ u64 dummy;
+
+ /* check for other users first */
+ if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+ == NOTIFY_STOP) {
+ touched = 1;
+ }

sum = per_cpu(irq_stat, cpu).apic_timer_irqs;

- if (last_irq_sums[cpu] == sum) {
+ /* if the apic timer isn't firing, this cpu isn't doing much */
+ if (!touched && last_irq_sums[cpu] == sum) {
/*
* Ayiee, looks like this CPU is stuck ...
* wait a few IRQs (5 seconds) before doing the oops ...
@@ -662,26 +818,41 @@ void nmi_watchdog_tick (struct pt_regs *
last_irq_sums[cpu] = sum;
alert_counter[cpu] = 0;
}
- if (nmi_perfctr_msr) {
- if (nmi_perfctr_msr == MSR_P4_IQ_COUNTER0) {
- /*
- * P4 quirks:
- * - An overflown perfctr will assert its interrupt
- * until the OVF flag in its CCCR is cleared.
- * - LVTPC is masked on interrupt and must be
- * unmasked by the LVTPC handler.
- */
- wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
- apic_write(APIC_LVTPC, APIC_DM_NMI);
- }
- else if (nmi_perfctr_msr == MSR_P6_PERFCTR0) {
- /* Only P6 based Pentium M need to re-unmask
- * the apic vector but it doesn't hurt
- * other P6 variant */
- apic_write(APIC_LVTPC, APIC_DM_NMI);
+ /* see if the nmi watchdog went off */
+ if (wd->enabled) {
+ if (nmi_watchdog == NMI_LOCAL_APIC) {
+ rdmsrl(wd->perfctr_msr, dummy);
+ if (dummy & wd->check_bit){
+ /* this wasn't a watchdog timer interrupt */
+ goto done;
+ }
+
+ /* only Intel P4 uses the cccr msr */
+ if (wd->cccr_msr != 0) {
+ /*
+ * P4 quirks:
+ * - An overflown perfctr will assert its interrupt
+ * until the OVF flag in its CCCR is cleared.
+ * - LVTPC is masked on interrupt and must be
+ * unmasked by the LVTPC handler.
+ */
+ rdmsrl(wd->cccr_msr, dummy);
+ dummy &= ~P4_CCCR_OVF;
+ wrmsrl(wd->cccr_msr, dummy);
+ apic_write(APIC_LVTPC, APIC_DM_NMI);
+ }
+ else if (wd->perfctr_msr == MSR_P6_PERFCTR0) {
+ /* Only P6 based Pentium M need to re-unmask
+ * the apic vector but it doesn't hurt
+ * other P6 variant */
+ apic_write(APIC_LVTPC, APIC_DM_NMI);
+ }
+ /* start the cycle over again */
+ write_watchdog_counter(wd->perfctr_msr, NULL);
}
- write_watchdog_counter(NULL);
}
+done:
+ return;
}

#ifdef CONFIG_SYSCTL
Index: linux-don/arch/i386/kernel/traps.c
===================================================================
--- linux-don.orig/arch/i386/kernel/traps.c
+++ linux-don/arch/i386/kernel/traps.c
@@ -691,7 +691,7 @@ static void default_do_nmi(struct pt_reg
* so it must be the NMI watchdog.
*/
if (nmi_watchdog) {
- nmi_watchdog_tick(regs);
+ nmi_watchdog_tick(regs, reason);
return;
}
#endif
Index: linux-don/include/asm-i386/nmi.h
===================================================================
--- linux-don.orig/include/asm-i386/nmi.h
+++ linux-don/include/asm-i386/nmi.h
@@ -32,13 +32,14 @@ extern void release_perfctr_nmi(unsigned
extern int reserve_evntsel_nmi(unsigned int);
extern void release_evntsel_nmi(unsigned int);

-extern void setup_apic_nmi_watchdog (void);
+extern void setup_apic_nmi_watchdog (void *);
extern int reserve_lapic_nmi(void);
extern void release_lapic_nmi(void);
extern void disable_timer_nmi_watchdog(void);
extern void enable_timer_nmi_watchdog(void);
-extern void nmi_watchdog_tick (struct pt_regs * regs);
+extern void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);

+extern atomic_t nmi_active;
extern unsigned int nmi_watchdog;
#define NMI_DEFAULT -1
#define NMI_NONE 0
Index: linux-don/arch/i386/oprofile/nmi_timer_int.c
===================================================================
--- linux-don.orig/arch/i386/oprofile/nmi_timer_int.c
+++ linux-don/arch/i386/oprofile/nmi_timer_int.c
@@ -42,9 +42,7 @@ static void timer_stop(void)

int __init op_nmi_timer_init(struct oprofile_operations * ops)
{
- extern int nmi_active;
-
- if (nmi_active <= 0)
+ if (atomic_read(&nmi_active) <= 0)
return -ENODEV;

ops->start = timer_start;

--
-
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