Unlock the largest standard CPUID on Intel CPUs for both amd64 and i386 and

fix SMP topology detection.  On i386, we extend it to cover Core, Core 2,
and Core i7 processors, not just Pentium 4 family, and move it to better
place.  On amd64, all supported Intel CPUs should have this MSR.

1 files changed, 18 insertions, 11 deletions

diff --git a/sys/i386/i386/identcpu.c b/sys/i386/i386/identcpu.c
index 60907a5..af0da5b 100644
--- a/sys/i386/i386/identcpu.c
+++ b/sys/i386/i386/identcpu.c
@@ -209,7 +209,6 @@ printcpuinfo(void)
 	if (cpu_vendor_id == CPU_VENDOR_INTEL) {
 		if ((cpu_id & 0xf00) > 0x300) {
 			u_int brand_index;
-			u_int model;
 
 			cpu_model[0] = '\0';
 
@@ -322,16 +321,6 @@ printcpuinfo(void)
 			case 0xf00:
 				strcat(cpu_model, "Pentium 4");
 				cpu = CPU_P4;
-				model = (cpu_id & 0x0f0) >> 4;
-				if (model == 3 || model == 4 || model == 6) {
-					uint64_t tmp;
-
-					tmp = rdmsr(MSR_IA32_MISC_ENABLE);
-					wrmsr(MSR_IA32_MISC_ENABLE,
-					      tmp & ~(1LL << 22));
-					do_cpuid(0, regs);
-					cpu_high = regs[0];
-				}
 				break;
 			default:
 				strcat(cpu_model, "unknown");
@@ -1110,6 +1099,24 @@ finishidentcpu(void)
 
 	cpu_vendor_id = find_cpu_vendor_id();
 
+	/*
+	 * Clear "Limit CPUID Maxval" bit and get the largest standard CPUID
+	 * function number again if it is set from BIOS.  It is necessary
+	 * for probing correct CPU topology later.
+	 * XXX This is only done on the BSP package.
+	 */
+	if (cpu_vendor_id == CPU_VENDOR_INTEL && cpu_high > 0 && cpu_high < 4 &&
+	    ((I386_CPU_FAMILY(cpu_id) == 0xf && I386_CPU_MODEL(cpu_id) >= 0x3) ||
+	    (I386_CPU_FAMILY(cpu_id) == 0x6 && I386_CPU_MODEL(cpu_id) >= 0xe))) {
+		uint64_t msr;
+		msr = rdmsr(MSR_IA32_MISC_ENABLE);
+		if ((msr & 0x400000ULL) != 0) {
+			wrmsr(MSR_IA32_MISC_ENABLE, msr & ~0x400000ULL);
+			do_cpuid(0, regs);
+			cpu_high = regs[0];
+		}
+	}
+
 	/* Detect AMD features (PTE no-execute bit, 3dnow, 64 bit mode etc) */
 	if (cpu_vendor_id == CPU_VENDOR_INTEL ||
 	    cpu_vendor_id == CPU_VENDOR_AMD) {