This patch (against 2.4.0-ac8) _may_ enable the NMI watchdog on
some K7 systems. It won't help if you have an old K7 without a
local APIC, or if your BIOS disables it.
This is a quick hack to test the mechanism -- I'll submit a
cleaner patch later if this one works.
If you try this, please cc: me the result (positive or negative)
and a copy of the kernel's boot log.
/Mikael
--- linux-2.4.0-ac8/arch/i386/kernel/nmi.c.~1~ Sat Jan 13 14:57:09 2001
+++ linux-2.4.0-ac8/arch/i386/kernel/nmi.c Sat Jan 13 16:00:27 2001
@@ -64,6 +64,10 @@
(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
(boot_cpu_data.x86 == 6))
nmi_watchdog = nmi;
+ if ((nmi == NMI_LOCAL_APIC) &&
+ (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&
+ (boot_cpu_data.x86 == 6))
+ nmi_watchdog = nmi;
/*
* We can enable the IO-APIC watchdog
* unconditionally.
@@ -80,10 +84,34 @@
* Original code written by Keith Owens.
*/
+#define MSR_K7_EVNTSEL0 0xC001000
+#define MSR_K7_PERFCTR0 0xC001004
+
void setup_apic_nmi_watchdog (void)
{
int value;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+ boot_cpu_data.x86 == 6) {
+ unsigned evntsel = (1<<20)|(3<<16); /* INT, OS, USR */
+#if 1 /* listed in old docs */
+ evntsel |= 0x76; /* CYCLES_PROCESSOR_IS_RUNNING */
+#else /* try this if the above doesn't work */
+ evntsel |= 0xC0; /* RETIRED_INSTRUCTIONS */
+#endif
+ wrmsr(MSR_K7_EVNTSEL0, 0, 0);
+ wrmsr(MSR_K7_PERFCTR0, 0, 0);
+ wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
+ printk("setting K7_PERFCTR0 to %08lx\n", -(cpu_khz/HZ*1000));
+ wrmsr(MSR_K7_PERFCTR0, -(cpu_khz/HZ*1000), 0);
+ printk("setting K7 LVTPC to DM_NMI\n");
+ apic_write(APIC_LVTPC, APIC_DM_NMI);
+ evntsel |= (1<<22); /* ENable */
+ printk("setting K7_EVNTSEL0 to %08x\n", evntsel);
+ wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
+ return;
+ }
+
/* clear performance counters 0, 1 */
wrmsr(MSR_IA32_EVNTSEL0, 0, 0);
@@ -162,7 +190,14 @@
last_irq_sums[cpu] = sum;
alert_counter[cpu] = 0;
}
- if (cpu_has_apic && (nmi_watchdog == NMI_LOCAL_APIC))
- wrmsr(MSR_IA32_PERFCTR1, -(cpu_khz/HZ*1000), 0);
+ if (cpu_has_apic && (nmi_watchdog == NMI_LOCAL_APIC)) {
+ /* XXX: nmi_watchdog should carry this info */
+ unsigned msr;
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+ msr = MSR_K7_PERFCTR0;
+ else
+ msr = MSR_IA32_PERFCTR1;
+ wrmsr(msr, -(cpu_khz/HZ*1000), 0);
+ }
}
--- linux-2.4.0-ac8/arch/i386/kernel/setup.c.~1~ Sat Jan 13 14:57:09 2001
+++ linux-2.4.0-ac8/arch/i386/kernel/setup.c Sat Jan 13 14:57:48 2001
@@ -1926,14 +1926,6 @@
c->x86 = 4;
}
- /*
- * Athlons have an APIC, but the APIC-programming
- * MSRs are in different places. If you want NMI-watchdog
- * on Athlons, please fix setup_apic_nmi_watchdog().
- */
- if (c->x86_vendor == X86_VENDOR_AMD)
- clear_bit(X86_FEATURE_APIC, &c->x86_capability);
-
/* AMD-defined flags: level 0x80000001 */
xlvl = cpuid_eax(0x80000000);
if ( (xlvl & 0xffff0000) == 0x80000000 ) {
-
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