Ryzen issues on FreeBSD ? (with sort of workaround)

[Konstantin Belousov]

On Thu, Jul 05, 2018 at 02:58:29PM +0100, Pete French wrote:
> > Which other files ?
> 
> sys/x86/include/specialreg.h and sys/x86/x86/cpu_machdep.c
> 
> Those are in your original patch as well as the change
> to sys/amd64/amd64/initcpu.c, but your email earlier only
> patches sys/amd64/amd64/initcpu.c and not the others.
> 
> So I assumed I would keep the changes to the other two files ?


Right, I forgot about mwait. specialreg.h is cosmetics which I already
committed.

diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
index ccc5e64d0c4..bb342f42dec 100644
--- a/sys/amd64/amd64/initcpu.c
+++ b/sys/amd64/amd64/initcpu.c
@@ -130,6 +130,30 @@ init_amd(void)
 		}
 	}
 
+	/* Ryzen erratas. */
+	if (CPUID_TO_FAMILY(cpu_id) == 0x17 && CPUID_TO_MODEL(cpu_id) == 0x1 &&
+	    (cpu_feature2 & CPUID2_HV) == 0) {
+		/* 1021 */
+		msr = rdmsr(0xc0011029);
+		msr |= 0x2000;
+		wrmsr(0xc0011029, msr);
+
+		/* 1033 */
+		msr = rdmsr(0xc0011020);
+		msr |= 0x10;
+		wrmsr(0xc0011020, msr);
+
+		/* 1049 */
+		msr = rdmsr(0xc0011028);
+		msr |= 0x10;
+		wrmsr(0xc0011028, msr);
+
+		/* 1095 */
+		msr = rdmsr(0xc0011020);
+		msr |= 0x200000000000000;
+		wrmsr(0xc0011020, msr);
+	}
+
 	/*
 	 * Work around a problem on Ryzen that is triggered by executing
 	 * code near the top of user memory, in our case the signal
diff --git a/sys/x86/x86/cpu_machdep.c b/sys/x86/x86/cpu_machdep.c
index d897d518cbc..3416f949686 100644
--- a/sys/x86/x86/cpu_machdep.c
+++ b/sys/x86/x86/cpu_machdep.c
@@ -709,6 +709,13 @@ cpu_idle_tun(void *unused __unused)
 
 	if (TUNABLE_STR_FETCH("machdep.idle", tunvar, sizeof(tunvar)))
 		cpu_idle_selector(tunvar);
+	else if (cpu_vendor_id == CPU_VENDOR_AMD &&
+	    CPUID_TO_FAMILY(cpu_id) == 0x17 && CPUID_TO_MODEL(cpu_id) == 0x1) {
+		/* Ryzen erratas 1057, 1109. */
+		cpu_idle_selector("hlt");
+		idle_mwait = 0;
+	}
+
 	if (cpu_vendor_id == CPU_VENDOR_INTEL && cpu_id == 0x506c9) {
 		/*
 		 * Apollo Lake errata APL31 (public errata APL30).