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From: Peter Zijlstra <peterz@infradead.org>
To: frederic@kernel.org, paulmck@kernel.org, rjw@rjwysocki.net,
	x86@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, jpoimboe@kernel.org
Subject: [RFC][PATCH 6/9] acpi_idle: Remove tracing
Date: Thu, 19 May 2022 23:27:56 +0200	[thread overview]
Message-ID: <20220519213421.938914850@infradead.org> (raw)
In-Reply-To: <20220519212750.656413111@infradead.org>

All the idle routines are called with RCU disabled, as such there must
not be any tracing inside.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 drivers/acpi/processor_idle.c |   24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -108,8 +108,8 @@ static const struct dmi_system_id proces
 static void __cpuidle acpi_safe_halt(void)
 {
 	if (!tif_need_resched()) {
-		safe_halt();
-		local_irq_disable();
+		raw_safe_halt();
+		raw_local_irq_disable();
 	}
 }
 
@@ -524,16 +524,21 @@ static int acpi_idle_bm_check(void)
 	return bm_status;
 }
 
-static void wait_for_freeze(void)
+static __cpuidle void io_idle(unsigned long addr)
 {
+	/* IO port based C-state */
+	inb(addr);
+
 #ifdef	CONFIG_X86
 	/* No delay is needed if we are in guest */
 	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return;
 #endif
-	/* Dummy wait op - must do something useless after P_LVL2 read
-	   because chipsets cannot guarantee that STPCLK# signal
-	   gets asserted in time to freeze execution properly. */
+	/*
+	 * Dummy wait op - must do something useless after P_LVL2 read
+	 * because chipsets cannot guarantee that STPCLK# signal
+	 * gets asserted in time to freeze execution properly.
+	 */
 	inl(acpi_gbl_FADT.xpm_timer_block.address);
 }
 
@@ -553,9 +558,7 @@ static void __cpuidle acpi_idle_do_entry
 	} else if (cx->entry_method == ACPI_CSTATE_HALT) {
 		acpi_safe_halt();
 	} else {
-		/* IO port based C-state */
-		inb(cx->address);
-		wait_for_freeze();
+		io_idle(cx->address);
 	}
 
 	perf_lopwr_cb(false);
@@ -577,8 +580,7 @@ static int acpi_idle_play_dead(struct cp
 		if (cx->entry_method == ACPI_CSTATE_HALT)
 			safe_halt();
 		else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
-			inb(cx->address);
-			wait_for_freeze();
+			io_idle(cx->address);
 		} else
 			return -ENODEV;
 



  parent reply	other threads:[~2022-05-19 21:41 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-19 21:27 [RFC][PATCH 0/9] Rework cpuidle vs instrumentation Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 1/9] x86/perf/amd: Remove tracing from perf_lopwr_cb() Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 2/9] x86/idle: Replace x86_idle with a static_call Peter Zijlstra
2022-05-30 11:07   ` Frederic Weisbecker
2022-05-19 21:27 ` [RFC][PATCH 3/9] cpuidle: Move IRQ state validation Peter Zijlstra
2022-05-30 11:36   ` Frederic Weisbecker
2022-05-30 12:00     ` Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 4/9] idle: Fix rcu_idle_*() usage Peter Zijlstra
2022-05-23  9:46   ` Gautham R. Shenoy
2022-05-31  9:33     ` Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 5/9] rcu: Fix rcu_idle_exit() Peter Zijlstra
2022-05-20 21:00   ` Paul E. McKenney
2022-05-19 21:27 ` Peter Zijlstra [this message]
2022-05-19 21:27 ` [RFC][PATCH 7/9] cpuidle: Annotate poll_idle() Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 8/9] objtool/idle: Validate __cpuidle code as noinstr Peter Zijlstra
2022-05-19 21:27 ` [RFC][PATCH 9/9] arch/idle: Change arch_cpu_idle() IRQ behaviour Peter Zijlstra
2022-05-19 22:03   ` Peter Zijlstra
2022-05-20  2:20     ` Kirill A. Shutemov
2022-05-20  7:06       ` Peter Zijlstra
2022-05-20 10:13         ` Kirill A. Shutemov
2022-05-20 12:58           ` Peter Zijlstra
2022-05-24 14:55             ` Isaku Yamahata
2022-05-23 10:02   ` Gautham R. Shenoy

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