Nuke options HTT infavor of machdep.hlt_logical_cpus tunable/sysctl.

This keeps the logical cpu's halted in the idle loop.  By default
the logical cpu's are halted at startup.  It is also possible to
halt any cpu in the idle loop now using machdep.hlt_cpus.

Examples of how to use this:
machdep.hlt_cpus=1	halt cpu0
machdep.hlt_cpus=2	halt cpu1
machdep.hlt_cpus=4	halt cpu2
machdep.hlt_cpus=3	halt cpu0,cpu1

Reviewed by:	jhb, peter

1 files changed, 88 insertions, 21 deletions

diff --git a/sys/i386/include/mptable.h b/sys/i386/include/mptable.h
index 12d7578..954a7fd 100644
--- a/sys/i386/include/mptable.h
+++ b/sys/i386/include/mptable.h
@@ -26,7 +26,6 @@
  */
 
 #include "opt_cpu.h"
-#include "opt_htt.h"
 #include "opt_kstack_pages.h"
 
 #ifdef SMP
@@ -238,10 +237,9 @@ typedef struct BASETABLE_ENTRY {
 
 #define MP_ANNOUNCE_POST	0x19
 
-#ifdef HTT
 static int need_hyperthreading_fixup;
 static u_int logical_cpus;
-#endif
+static u_int logical_cpus_mask;
 
 /* used to hold the AP's until we are ready to release them */
 static struct mtx ap_boot_mtx;
@@ -318,9 +316,7 @@ static mpfps_t	mpfps;
 static int	search_for_sig(u_int32_t target, int count);
 static void	mp_enable(u_int boot_addr);
 
-#ifdef HTT
 static void	mptable_hyperthread_fixup(u_int id_mask);
-#endif
 static void	mptable_pass1(void);
 static int	mptable_pass2(void);
 static void	default_mp_table(int type);
@@ -791,9 +787,7 @@ mptable_pass1(void)
 	void*	position;
 	int	count;
 	int	type;
-#ifdef HTT
 	u_int	id_mask;
-#endif
 
 	POSTCODE(MPTABLE_PASS1_POST);
 
@@ -807,9 +801,7 @@ mptable_pass1(void)
 	mp_nbusses = 0;
 	mp_napics = 0;
 	nintrs = 0;
-#ifdef HTT
 	id_mask = 0;
-#endif
 
 	/* check for use of 'default' configuration */
 	if (MPFPS_MPFB1 != 0) {
@@ -844,10 +836,8 @@ mptable_pass1(void)
 				    & PROCENTRY_FLAG_EN) {
 					++mp_naps;
 					mp_maxid++;
-#ifdef HTT
 					id_mask |= 1 <<
 					    ((proc_entry_ptr)position)->apic_id;
-#endif
 				}
 				break;
 			case 1: /* bus_entry */
@@ -882,10 +872,8 @@ mptable_pass1(void)
 		mp_naps = MAXCPU;
 	}
 
-#ifdef HTT
 	/* See if we need to fixup HT logical CPUs. */
 	mptable_hyperthread_fixup(id_mask);
-#endif
 	
 	/*
 	 * Count the BSP.
@@ -911,9 +899,7 @@ mptable_pass1(void)
 static int
 mptable_pass2(void)
 {
-#ifdef HTT
 	struct PROCENTRY proc;
-#endif
 	int     x;
 	mpcth_t cth;
 	int     totalSize;
@@ -926,12 +912,10 @@ mptable_pass2(void)
 
 	POSTCODE(MPTABLE_PASS2_POST);
 
-#ifdef HTT
 	/* Initialize fake proc entry for use with HT fixup. */
 	bzero(&proc, sizeof(proc));
 	proc.type = 0;
 	proc.cpu_flags = PROCENTRY_FLAG_EN;
-#endif
 
 	pgeflag = 0;		/* XXX - Not used under SMP yet.  */
 
@@ -1011,7 +995,6 @@ mptable_pass2(void)
 			if (processor_entry(position, cpu))
 				++cpu;
 
-#ifdef HTT
 			if (need_hyperthreading_fixup) {
 				/*
 				 * Create fake mptable processor entries
@@ -1022,10 +1005,10 @@ mptable_pass2(void)
 				for (i = 1; i < logical_cpus; i++) {
 					proc.apic_id++;
 					(void)processor_entry(&proc, cpu);
+					logical_cpus_mask |= (1 << cpu);
 					cpu++;
 				}
 			}
-#endif
 			break;
 		case 1:
 			if (bus_entry(position, bus))
@@ -1058,7 +1041,6 @@ mptable_pass2(void)
 	return 0;
 }
 
-#ifdef HTT
 /*
  * Check if we should perform a hyperthreading "fix-up" to
  * enumerate any logical CPU's that aren't already listed
@@ -1108,7 +1090,6 @@ mptable_hyperthread_fixup(u_int id_mask)
 	mp_maxid *= logical_cpus;
 	mp_naps *= logical_cpus;
 }
-#endif
 
 void
 assign_apic_irq(int apic, int intpin, int irq)
@@ -2760,3 +2741,89 @@ release_aps(void *dummy __unused)
 }
 
 SYSINIT(start_aps, SI_SUB_SMP, SI_ORDER_FIRST, release_aps, NULL);
+
+static int	hlt_cpus_mask;
+static int	hlt_logical_cpus = 1;
+static struct	sysctl_ctx_list logical_cpu_clist;
+
+static int
+sysctl_hlt_cpus(SYSCTL_HANDLER_ARGS)
+{
+	u_int mask;
+	int error;
+
+	mask = hlt_cpus_mask;
+	error = sysctl_handle_int(oidp, &mask, 0, req);
+	if (error || !req->newptr)
+		return (error);
+
+	if (logical_cpus_mask != 0 &&
+	    (mask & logical_cpus_mask) == logical_cpus_mask)
+		hlt_logical_cpus = 1;
+	else
+		hlt_logical_cpus = 0;
+
+	if ((mask & all_cpus) == all_cpus)
+		mask &= ~(1<<0);
+	hlt_cpus_mask = mask;
+	return (error);
+}
+SYSCTL_PROC(_machdep, OID_AUTO, hlt_cpus, CTLTYPE_INT|CTLFLAG_RW,
+    0, 0, sysctl_hlt_cpus, "IU", "");
+
+static int
+sysctl_hlt_logical_cpus(SYSCTL_HANDLER_ARGS)
+{
+	int disable, error;
+
+	disable = hlt_logical_cpus;
+	error = sysctl_handle_int(oidp, &disable, 0, req);
+	if (error || !req->newptr)
+		return (error);
+
+	if (disable)
+		hlt_cpus_mask |= logical_cpus_mask;
+	else
+		hlt_cpus_mask &= ~logical_cpus_mask;
+
+	if ((hlt_cpus_mask & all_cpus) == all_cpus)
+		hlt_cpus_mask &= ~(1<<0);
+
+	hlt_logical_cpus = disable;
+	return (error);
+}
+
+static void
+cpu_hlt_setup(void *dummy __unused)
+{
+
+	if (logical_cpus_mask != 0) {
+		TUNABLE_INT_FETCH("machdep.hlt_logical_cpus",
+		    &hlt_logical_cpus);
+		sysctl_ctx_init(&logical_cpu_clist);
+		SYSCTL_ADD_PROC(&logical_cpu_clist,
+		    SYSCTL_STATIC_CHILDREN(_machdep), OID_AUTO,
+		    "hlt_logical_cpus", CTLTYPE_INT|CTLFLAG_RW, 0, 0,
+		    sysctl_hlt_logical_cpus, "IU", "");
+		SYSCTL_ADD_UINT(&logical_cpu_clist,
+		    SYSCTL_STATIC_CHILDREN(_machdep), OID_AUTO,
+		    "logical_cpus_mask", CTLTYPE_INT|CTLFLAG_RD,
+		    &logical_cpus_mask, 0, "");
+
+		if (hlt_logical_cpus)
+			hlt_cpus_mask |= logical_cpus_mask;
+	}
+}
+SYSINIT(cpu_hlt, SI_SUB_SMP, SI_ORDER_ANY, cpu_hlt_setup, NULL);
+
+int
+mp_grab_cpu_hlt(void)
+{
+	u_int mask = PCPU_GET(cpumask);
+	int retval;
+
+	retval = mask & hlt_cpus_mask;
+	while (mask & hlt_cpus_mask)
+		__asm __volatile("sti; hlt" : : : "memory");
+	return (retval);
+}