Make sure we select the deepest possible C-state during suspend-to-idle.

ok deraadt@, guenther@, mlarkin@, jsg@

6 files changed, 18 insertions, 8 deletions

diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
index 6714c0237f9..8df6de03b89 100644
--- a/sys/arch/amd64/amd64/cpu.c
+++ b/sys/arch/amd64/amd64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.189 2024/05/29 12:21:33 kettenis Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.190 2024/06/07 16:53:35 kettenis Exp $	*/
 /* $NetBSD: cpu.c,v 1.1 2003/04/26 18:39:26 fvdl Exp $ */
 
 /*-
@@ -1469,7 +1469,10 @@ int cpu_suspended;
 void
 cpu_suspend_cycle(void)
 {
-	cpu_idle_cycle_fcn();
+	if (cpu_suspend_cycle_fcn)
+		cpu_suspend_cycle_fcn();
+	else
+		cpu_idle_cycle_fcn();
 }
 
 int
diff --git a/sys/arch/amd64/amd64/ipifuncs.c b/sys/arch/amd64/amd64/ipifuncs.c
index 5c330d7a139..482fc9eebb4 100644
--- a/sys/arch/amd64/amd64/ipifuncs.c
+++ b/sys/arch/amd64/amd64/ipifuncs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ipifuncs.c,v 1.38 2023/10/30 12:50:59 mvs Exp $	*/
+/*	$OpenBSD: ipifuncs.c,v 1.39 2024/06/07 16:53:35 kettenis Exp $	*/
 /*	$NetBSD: ipifuncs.c,v 1.1 2003/04/26 18:39:28 fvdl Exp $ */
 
 /*-
@@ -128,7 +128,10 @@ x86_64_ipi_halt(struct cpu_info *ci)
 	wbinvd();
 
 	for(;;) {
-		__asm volatile("hlt");
+		if (cpu_suspend_cycle_fcn)
+			cpu_suspend_cycle_fcn();
+		else
+			__asm volatile("hlt");
 	}
 }
 
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index 343cc0f7e52..35cea0b5810 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.293 2024/04/29 00:29:48 jsg Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.294 2024/06/07 16:53:35 kettenis Exp $	*/
 /*	$NetBSD: machdep.c,v 1.3 2003/05/07 22:58:18 fvdl Exp $	*/
 
 /*-
@@ -162,6 +162,7 @@ char machine[] = MACHINE;
  */
 void cpu_idle_cycle_hlt(void);
 void (*cpu_idle_cycle_fcn)(void) = &cpu_idle_cycle_hlt;
+void (*cpu_suspend_cycle_fcn)(void);
 
 /* the following is used externally for concurrent handlers */
 int setperf_prio = 0;
diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index fab34e5bd9d..90f5dd9e905 100644
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.171 2024/05/29 12:21:33 kettenis Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.172 2024/06/07 16:53:35 kettenis Exp $	*/
 /*	$NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $	*/
 
 /*-
@@ -420,6 +420,7 @@ void	cpu_proc_fork(struct proc *, struct proc *);
 int	amd64_pa_used(paddr_t);
 #define	cpu_idle_enter()	do { /* nothing */ } while (0)
 extern void (*cpu_idle_cycle_fcn)(void);
+extern void (*cpu_suspend_cycle_fcn)(void);
 #define	cpu_idle_cycle()	(*cpu_idle_cycle_fcn)()
 #define	cpu_idle_leave()	do { /* nothing */ } while (0)
 extern void (*initclock_func)(void);
diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index a75259a7474..49999ca6685 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.671 2024/05/26 13:37:32 kettenis Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.672 2024/06/07 16:53:35 kettenis Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -167,6 +167,7 @@ char machine[] = MACHINE;
 void (*cpu_idle_leave_fcn)(void) = NULL;
 void (*cpu_idle_cycle_fcn)(void) = NULL;
 void (*cpu_idle_enter_fcn)(void) = NULL;
+void (*cpu_suspend_cycle_fcn)(void);
 
 
 struct uvm_constraint_range  isa_constraint = { 0x0, 0x00ffffffUL };
diff --git a/sys/arch/i386/include/cpu.h b/sys/arch/i386/include/cpu.h
index 1c2d693846c..565f6159c74 100644
--- a/sys/arch/i386/include/cpu.h
+++ b/sys/arch/i386/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.189 2024/05/21 23:16:06 jsg Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.190 2024/06/07 16:53:35 kettenis Exp $	*/
 /*	$NetBSD: cpu.h,v 1.35 1996/05/05 19:29:26 christos Exp $	*/
 
 /*-
@@ -375,6 +375,7 @@ extern const struct cpu_cpuid_nameclass i386_cpuid_cpus[];
 extern void (*cpu_idle_enter_fcn)(void);
 extern void (*cpu_idle_cycle_fcn)(void);
 extern void (*cpu_idle_leave_fcn)(void);
+extern void (*cpu_suspend_cycle_fcn)(void);
 
 extern int cpuspeed;