From aa08aab774dbcd6ea6c1c1a9c137f951e7876d28 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Fri, 27 Jan 2023 23:11:59 +0000
Subject: [PATCH] Only use the CPU_OFF PSCI call if SYSTEM_SUSPEND is
 supported.  This means that secondary CPUs will get parked in a WFI loop like
 we already do on Apple Silicon systems.  This requires some small changes in
 agintc(4) to make sure we ack the "halt" IPI such that we can send a "wakeup"
 IPI later.

ok patrick@
---
 sys/arch/arm64/arm64/cpu.c  | 10 ++++++----
 sys/arch/arm64/dev/agintc.c | 12 +++++++++++-
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/sys/arch/arm64/arm64/cpu.c b/sys/arch/arm64/arm64/cpu.c
index daef07d3ea6..e40634efb58 100644
--- a/sys/arch/arm64/arm64/cpu.c
+++ b/sys/arch/arm64/arm64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.80 2023/01/26 13:09:18 kettenis Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.81 2023/01/27 23:11:59 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2016 Dale Rahn <drahn@dalerahn.com>
@@ -1064,17 +1064,19 @@ cpu_halt(void)
 {
 	struct cpu_info *ci = curcpu();
 	int count = 0;
+	u_long psw;
 
 	KERNEL_ASSERT_UNLOCKED();
 	SCHED_ASSERT_UNLOCKED();
 
-	intr_disable();
+	psw = intr_disable();
 
 	atomic_clearbits_int(&ci->ci_flags,
 	    CPUF_RUNNING | CPUF_PRESENT | CPUF_GO);
 
 #if NPSCI > 0
-	psci_cpu_off();
+	if (psci_can_suspend())
+		psci_cpu_off();
 #endif
 
 	/*
@@ -1097,7 +1099,7 @@ cpu_halt(void)
 	atomic_setbits_int(&ci->ci_flags, CPUF_RUNNING);
 	__asm volatile("dsb sy; sev" ::: "memory");
 
-	intr_enable();
+	intr_restore(psw);
 
 	/* Unmask clock interrupts. */
 	WRITE_SPECIALREG(cntv_ctl_el0,
diff --git a/sys/arch/arm64/dev/agintc.c b/sys/arch/arm64/dev/agintc.c
index 02989a4e94f..905b5118c70 100644
--- a/sys/arch/arm64/dev/agintc.c
+++ b/sys/arch/arm64/dev/agintc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: agintc.c,v 1.46 2022/12/21 23:18:09 patrick Exp $ */
+/* $OpenBSD: agintc.c,v 1.47 2023/01/27 23:11:59 kettenis Exp $ */
 /*
  * Copyright (c) 2007, 2009, 2011, 2017 Dale Rahn <drahn@dalerahn.com>
  * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
@@ -1396,7 +1396,17 @@ agintc_ipi_ddb(void *v)
 int
 agintc_ipi_halt(void *v)
 {
+	struct agintc_softc *sc = v;
+	int old = curcpu()->ci_cpl;
+
+	intr_disable();
+	agintc_eoi(sc->sc_ipi_num[ARM_IPI_HALT]);
+	agintc_setipl(IPL_NONE);
+
 	cpu_halt();
+
+	agintc_setipl(old);
+	intr_enable();
 	return 1;
 }
 
-- 
2.20.1