Move C1E workaround into its own idle function. Previous workaround works

only during initial booting process, while there are laptops/BIOSes that
tend to act 'smarter' by force enabling C1E if the main power adapter
being pulled out, rendering previous workaround ineffective. Given the
fact that we still rely on local APIC to drive timer interrupt, this
workaround should keep all Turion (probably Phenom too) X\d+ alive whether
its on battery power or not.

URL:		http://lists.freebsd.org/pipermail/freebsd-acpi/2008-April/004858.html
    		http://lists.freebsd.org/pipermail/freebsd-acpi/2008-May/004888.html

Tested by:	Peter Jeremy <peterjeremy at optushome d com d au>

2 files changed, 73 insertions, 23 deletions

diff --git a/sys/amd64/amd64/local_apic.c b/sys/amd64/amd64/local_apic.c
index 0a102ee..6ed6c9c 100644
--- a/sys/amd64/amd64/local_apic.c
+++ b/sys/amd64/amd64/local_apic.c
@@ -329,29 +329,6 @@ lapic_setup(int boot)
 
 	/* XXX: Error and thermal LVTs */
 
-	if (cpu_vendor_id == CPU_VENDOR_AMD) {
-		/*
-		 * Detect the presence of C1E capability mostly on latest
-		 * dual-cores (or future) k8 family.  This 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(0xc0010055);
-			if (msr & 0x18000000)
-				wrmsr(0xc0010055, msr & ~0x18000000ULL);
-		}
-	}
-
 	intr_restore(eflags);
 }
 
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 6993dea..de89c3b 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -600,6 +600,69 @@ cpu_idle_acpi(int busy)
 		__asm __volatile("sti; hlt");
 }
 
+static int cpu_ident_amdc1e = 0;
+
+static int
+cpu_probe_amdc1e(void)
+{
+	int i;
+
+	/*
+	 * Forget it, if we're not using local APIC timer.
+	 */
+	if (resource_disabled("apic", 0) ||
+	    (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0))
+		return (0);
+
+	/*
+	 * Detect the presence of C1E capability mostly on latest
+	 * dual-cores (or future) k8 family.
+	 */
+	if (cpu_vendor_id == CPU_VENDOR_AMD &&
+	    (cpu_id & 0x00000f00) == 0x00000f00 &&
+	    (cpu_id & 0x0fff0000) >=  0x00040000) {
+		cpu_ident_amdc1e = 1;
+		return (1);
+	}
+
+	return (0);
+}
+
+/*
+ * C1E 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+
+ */
+#define	MSR_AMDK8_IPM		0xc0010055
+#define	AMDK8_SMIONCMPHALT	(1ULL << 27)
+#define	AMDK8_C1EONCMPHALT	(1ULL << 28)
+#define	AMDK8_CMPHALT		(AMDK8_SMIONCMPHALT | AMDK8_C1EONCMPHALT)
+
+static void
+cpu_idle_amdc1e(int busy)
+{
+
+	disable_intr();
+	if (sched_runnable())
+		enable_intr();
+	else {
+		uint64_t msr;
+
+		msr = rdmsr(MSR_AMDK8_IPM);
+		if (msr & AMDK8_CMPHALT)
+			wrmsr(MSR_AMDK8_IPM, msr & ~AMDK8_CMPHALT);
+
+		if (cpu_idle_hook)
+			cpu_idle_hook();
+		else
+			__asm __volatile("sti; hlt");
+	}
+}
+
 static void
 cpu_idle_spin(int busy)
 {
@@ -697,6 +760,7 @@ struct {
 	{ cpu_idle_spin, "spin" },
 	{ cpu_idle_mwait, "mwait" },
 	{ cpu_idle_mwait_hlt, "mwait_hlt" },
+	{ cpu_idle_amdc1e, "amdc1e" },
 	{ cpu_idle_hlt, "hlt" },
 	{ cpu_idle_acpi, "acpi" },
 	{ NULL, NULL }
@@ -715,6 +779,9 @@ idle_sysctl_available(SYSCTL_HANDLER_ARGS)
 		if (strstr(idle_tbl[i].id_name, "mwait") &&
 		    (cpu_feature2 & CPUID2_MON) == 0)
 			continue;
+		if (strcmp(idle_tbl[i].id_name, "amdc1e") == 0 &&
+		    cpu_ident_amdc1e == 0)
+			continue;
 		p += sprintf(p, "%s, ", idle_tbl[i].id_name);
 	}
 	error = sysctl_handle_string(oidp, avail, 0, req);
@@ -745,6 +812,9 @@ idle_sysctl(SYSCTL_HANDLER_ARGS)
 		if (strstr(idle_tbl[i].id_name, "mwait") &&
 		    (cpu_feature2 & CPUID2_MON) == 0)
 			continue;
+		if (strcmp(idle_tbl[i].id_name, "amdc1e") == 0 &&
+		    cpu_ident_amdc1e == 0)
+			continue;
 		if (strcmp(idle_tbl[i].id_name, buf))
 			continue;
 		cpu_idle_fn = idle_tbl[i].id_fn;
@@ -1593,6 +1663,9 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
 	}
 #endif
 
+	if (cpu_probe_amdc1e())
+		cpu_idle_fn = cpu_idle_amdc1e;
+
 	/* Location of kernel stack for locore */
 	return ((u_int64_t)thread0.td_pcb);
 }