Disable the fantastics mis-feature on some newer Turion CPUs called C1E.

This "power saving" disables the apic when both cpu cores hit the hlt
instruction which kills our timer.

From FreeBSD.

diff --git a/sys/arch/amd64/amd64/lapic.c b/sys/arch/amd64/amd64/lapic.c
index 603cd4d..df55dc0 100644 (file)
--- a/sys/arch/amd64/amd64/lapic.c
+++ b/sys/arch/amd64/amd64/lapic.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: lapic.c,v 1.14 2008/06/26 05:42:09 ray Exp $  */
+/*     $OpenBSD: lapic.c,v 1.15 2008/08/13 15:44:44 art Exp $  */
 /* $NetBSD: lapic.c,v 1.2 2003/05/08 01:04:35 fvdl Exp $ */
 
 /*-
@@ -157,6 +157,31 @@ lapic_set_lvt(void)
        }
 #endif
 
+       if (strcmp(cpu_vendor, "AuthenticAMD") == 0) {
+               /*
+                * Detect the presence of C1E capability mostly on latest
+                * dual-cores (or future) k8 family. This mis-feature renders
+                * the local APIC timer dead, so we disable it by reading
+                * the Interrupt Pending Message register and clearing both
+                * C1eOnCmpHalt (bit 28) and SmiOnCmpHalt (bit 27).
+                * 
+                * Reference:
+                *   "BIOS and Kernel Developer's Guide for AMD NPT
+                *    Family 0Fh Processors"
+                *   #32559 revision 3.00
+                */
+               if ((cpu_id & 0x00000f00) == 0x00000f00 &&
+                   (cpu_id & 0x0fff0000) >= 0x00040000) {
+                       uint64_t msr;
+
+                       msr = rdmsr(MSR_INT_PEN_MSG);
+                       if (msr & (IPM_C1E_CMP_HLT|IPM_SMI_CMP_HLT)) {
+                               msr &= ~(IPM_C1E_CMP_HLT|IPM_SMI_CMP_HLT);
+                               wrmsr(MSR_INT_PEN_MSG, msr);
+                       }
+               }
+       }
+
        for (i = 0; i < mp_nintrs; i++) {
                mpi = &mp_intrs[i];
                if (mpi->ioapic == NULL && (mpi->cpu_id == MPS_ALL_APICS

diff --git a/sys/arch/amd64/include/specialreg.h b/sys/arch/amd64/include/specialreg.h
index 0fc1094..f8d7448 100644 (file)
--- a/sys/arch/amd64/include/specialreg.h
+++ b/sys/arch/amd64/include/specialreg.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: specialreg.h,v 1.12 2008/06/13 00:00:45 jsg Exp $     */
+/*     $OpenBSD: specialreg.h,v 1.13 2008/08/13 15:44:44 art Exp $     */
 /*     $NetBSD: specialreg.h,v 1.1 2003/04/26 18:39:48 fvdl Exp $      */
 /*     $NetBSD: x86/specialreg.h,v 1.2 2003/04/25 21:54:30 fvdl Exp $  */
 
@@ -289,6 +289,10 @@
 #define MSR_FSBASE     0xc0000100              /* 64bit offset for fs: */
 #define MSR_GSBASE     0xc0000101              /* 64bit offset for gs: */
 #define MSR_KERNELGSBASE 0xc0000102            /* storage for swapgs ins */
+#define MSR_INT_PEN_MSG        0xc0010055              /* Interrupt pending message */
+
+#define IPM_C1E_CMP_HLT        0x10000000
+#define IPM_SMI_CMP_HLT        0x08000000
 
 /*
  * These require a 'passcode' for access.  See cpufunc.h.