detect mwait capabilities and extensions

[Andriy Gapon]

Guys,

could you please the following change?
It is amd64-centric now, but obviously I plan equivalent changes for i386.
I am mostly concerned about proper header files for various definitions and
proper names for them.  Especially I am not sure where to put STATE_RUNNING,
STATE_MWAIT, STATE_SLEEPING...

Thank you.

diff --git a/sys/amd64/amd64/identcpu.c b/sys/amd64/amd64/identcpu.c
index 2517498..d831f95 100644
--- a/sys/amd64/amd64/identcpu.c
+++ b/sys/amd64/amd64/identcpu.c
@@ -513,6 +513,13 @@ identify_cpu(void)
 		}
 	}

+	if (cpu_high >= 5 && (cpu_feature2 & CPUID2_MON) != 0) {
+		do_cpuid(5, regs);
+		cpu_mon_mwait_flags = regs[2];
+		cpu_mon_min_size = regs[0] &  CPUID5_MON_MIN_SIZE;
+		cpu_mon_max_size = regs[1] &  CPUID5_MON_MAX_SIZE;
+	}
+
 	if (cpu_high >= 7) {
 		cpuid_count(7, 0, regs);
 		cpu_stdext_feature = regs[1];
diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
index 4abed4c..f7574b1 100644
--- a/sys/amd64/amd64/initcpu.c
+++ b/sys/amd64/amd64/initcpu.c
@@ -75,6 +75,9 @@ u_int	cpu_mxcsr_mask;		/* Valid bits in mxcsr */
 u_int	cpu_clflush_line_size = 32;
 u_int	cpu_stdext_feature;
 u_int	cpu_max_ext_state_size;
+u_int	cpu_mon_mwait_flags;	/* MONITOR/MWAIT flags (CPUID.05H.ECX) */
+u_int	cpu_mon_min_size;	/* MONITOR minimum range size, bytes */
+u_int	cpu_mon_max_size;	/* MONITOR minimum range size, bytes */

 SYSCTL_UINT(_hw, OID_AUTO, via_feature_rng, CTLFLAG_RD,
 	&via_feature_rng, 0, "VIA RNG feature available in CPU");
diff --git a/sys/amd64/include/md_var.h b/sys/amd64/include/md_var.h
index 5d7cb74..ddc5b9f 100644
--- a/sys/amd64/include/md_var.h
+++ b/sys/amd64/include/md_var.h
@@ -58,6 +58,9 @@ extern	u_int	cpu_procinfo;
 extern	u_int	cpu_procinfo2;
 extern	char	cpu_vendor[];
 extern	u_int	cpu_vendor_id;
+extern	u_int	cpu_mon_mwait_flags;
+extern	u_int	cpu_mon_min_size;
+extern	u_int	cpu_mon_max_size;
 extern	char	ctx_switch_xsave[];
 extern	char	kstack[];
 extern	char	sigcode[];
diff --git a/sys/x86/include/specialreg.h b/sys/x86/include/specialreg.h
index dbf9ba0..af64c1b 100644
--- a/sys/x86/include/specialreg.h
+++ b/sys/x86/include/specialreg.h
@@ -240,6 +240,29 @@
 #define	CPUID_LOCAL_APIC_ID	0xff000000

 /*
+ * CPUID instruction 5 info
+ */
+#define	CPUID5_MON_MIN_SIZE	0x0000ffff	/* eax */
+#define	CPUID5_MON_MAX_SIZE	0x0000ffff	/* ebx */
+#define	CPUID5_MON_MWAIT_EXT	0x00000001	/* ecx */
+#define	CPUID5_MWAIT_INTRBREAK	0x00000002	/* ecx */
+
+/*
+ * MWAIT cpu power states.  Lower 4 bits are sub-states.
+ */
+#define	MWAIT_C0	0xf0
+#define	MWAIT_C1	0x00
+#define	MWAIT_C2	0x10
+#define	MWAIT_C3	0x20
+#define	MWAIT_C4	0x30
+
+/*
+ * MWAIT extensions.
+ */
+/* Interrupt breaks MWAIT even when masked. */
+#define	MWAIT_INTRBREAK		0x00000001
+
+/*
  * CPUID instruction 6 ecx info
  */
 #define	CPUID_PERF_STAT		0x00000001

--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -665,10 +665,6 @@ TUNABLE_INT("machdep.idle_mwait", &idle_mwait);
 SYSCTL_INT(_machdep, OID_AUTO, idle_mwait, CTLFLAG_RW, &idle_mwait,
     0, "Use MONITOR/MWAIT for short idle");

-#define	STATE_RUNNING	0x0
-#define	STATE_MWAIT	0x1
-#define	STATE_SLEEPING	0x2
-
 static void
 cpu_idle_acpi(int busy)
 {
diff --git a/sys/amd64/include/cpu.h b/sys/amd64/include/cpu.h
index 1c2871f..dc29a37 100644
--- a/sys/amd64/include/cpu.h
+++ b/sys/amd64/include/cpu.h
@@ -43,8 +43,14 @@
 #include <machine/frame.h>
 #include <machine/segments.h>

+/*
+ * CPU states for the purpose of communication using MONITOR+MWAIT. */
+#define	STATE_RUNNING	0x0
+#define	STATE_MWAIT	0x1
+#define	STATE_SLEEPING	0x2
+
 #define	cpu_exec(p)	/* nothing */
 #define	cpu_swapin(p)	/* nothing */
 #define	cpu_getstack(td)		((td)->td_frame->tf_rsp)
 #define	cpu_setstack(td, ap)		((td)->td_frame->tf_rsp = (ap))
 #define	cpu_spinwait()			ia32_pause()



-- 
Andriy Gapon