From be3e4ce734139ed581c3e1064647f49864baa6fe Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Thu, 4 Jun 2015 18:01:44 +0000
Subject: [PATCH] The (no quite so) new kernel perfpolicy code calls
 cpu_setperf() from a timeout.  Unfortunately the smu(4) CPU voltage slewing
 code sleeps, which causes a kernel panic.  Prevent this by delegating the CPU
 frequency switching and voltage slewing to a task.

ok mpi@
---
 sys/arch/macppc/dev/smu.c    |  6 +++++-
 sys/arch/macppc/macppc/cpu.c | 21 +++++++++++++++++----
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/sys/arch/macppc/dev/smu.c b/sys/arch/macppc/dev/smu.c
index 28e8ac155f3..d811aa29b0c 100644
--- a/sys/arch/macppc/dev/smu.c
+++ b/sys/arch/macppc/dev/smu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: smu.c,v 1.26 2014/10/08 16:07:45 deraadt Exp $	*/
+/*	$OpenBSD: smu.c,v 1.27 2015/06/04 18:01:44 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2005 Mark Kettenis
@@ -742,6 +742,8 @@ smu_slew_voltage(u_int freq_scale)
 	struct smu_softc *sc = smu_cd.cd_devs[0];
 	struct smu_cmd *cmd = (struct smu_cmd *)sc->sc_cmd;
 
+	rw_enter_write(&sc->sc_lock);
+
 	cmd->cmd = SMU_POWER;
 	cmd->len = 8;
 	memcpy(cmd->data, "VSLEW", 5);
@@ -750,4 +752,6 @@ smu_slew_voltage(u_int freq_scale)
 	cmd->data[7] = freq_scale;
 
 	smu_do_cmd(sc, 250);
+
+	rw_exit_write(&sc->sc_lock);
 }
diff --git a/sys/arch/macppc/macppc/cpu.c b/sys/arch/macppc/macppc/cpu.c
index c6b055e5234..db486dcc1bf 100644
--- a/sys/arch/macppc/macppc/cpu.c
+++ b/sys/arch/macppc/macppc/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.81 2015/03/31 16:00:38 mpi Exp $ */
+/*	$OpenBSD: cpu.c,v 1.82 2015/06/04 18:01:44 kettenis Exp $ */
 
 /*
  * Copyright (c) 1997 Per Fogelstrom
@@ -37,6 +37,7 @@
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/sysctl.h>
+#include <sys/task.h>
 #include <sys/device.h>
 #include <dev/rndvar.h>
 
@@ -155,10 +156,13 @@ ppc64_scale_frequency(u_int freq_scale)
 
 extern int perflevel;
 
+struct task ppc64_setperf_task;
+int ppc64_perflevel;
+
 void
-ppc64_setperf(int speed)
+ppc64_do_setperf(void *arg)
 {
-	if (speed <= 50) {
+	if (ppc64_perflevel <= 50) {
 		if (ppc_curfreq == ppc_maxfreq / 2)
 			return;
 
@@ -175,6 +179,13 @@ ppc64_setperf(int speed)
 	}
 }
 
+void
+ppc64_setperf(int level)
+{
+	ppc64_perflevel = level;
+	task_add(systq, &ppc64_setperf_task);
+}
+
 void
 cpuattach(struct device *parent, struct device *dev, void *aux)
 {
@@ -318,8 +329,10 @@ cpuattach(struct device *parent, struct device *dev, void *aux)
 		}
 
 		if (OF_getprop(qhandle, "power-mode-data",
-		    &ppc_power_mode_data, sizeof ppc_power_mode_data) >= 8)
+		    &ppc_power_mode_data, sizeof ppc_power_mode_data) >= 8) {
+			task_set(&ppc64_setperf_task, ppc64_do_setperf, NULL);
 			cpu_setperf = ppc64_setperf;
+		}
 	}
 
 	/* power savings mode */
-- 
2.20.1