linux-kernel - [PATCH 4.16 144/279] ARM: OMAP2+: powerdomain: use raw_smp_processor

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Date:   Mon, 18 Jun 2018 10:12:09 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Tero Kristo <t-kristo@...com>,
        Tony Lindgren <tony@...mide.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.16 144/279] ARM: OMAP2+: powerdomain: use raw_smp_processor_id() for trace

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tero Kristo <t-kristo@...com>

[ Upstream commit 33e9572483031a79ad0a4468064675144d9269ec ]

smp_processor_id() checks preemption if CONFIG_DEBUG_PREEMPT is enabled,
causing a warning dump during boot:

[    5.042377] BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
[    5.050281] caller is pwrdm_set_next_pwrst+0x48/0x88
[    5.055330] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.14.24-g57341df0b4 #1

Use the raw_smp_processor_id() for the trace instead, this value does
not need to be perfectly correct. The alternative of disabling preempt
is too heavy weight operation to be applied in PM hot path for just
tracing purposes.

Signed-off-by: Tero Kristo <t-kristo@...com>
Signed-off-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/arm/mach-omap2/powerdomain.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -188,7 +188,7 @@ static int _pwrdm_state_switch(struct po
 				       ((prev & OMAP_POWERSTATE_MASK) << 0));
 			trace_power_domain_target_rcuidle(pwrdm->name,
 							  trace_state,
-							  smp_processor_id());
+							  raw_smp_processor_id());
 		}
 		break;
 	default:
@@ -518,7 +518,7 @@ int pwrdm_set_next_pwrst(struct powerdom
 	if (arch_pwrdm && arch_pwrdm->pwrdm_set_next_pwrst) {
 		/* Trace the pwrdm desired target state */
 		trace_power_domain_target_rcuidle(pwrdm->name, pwrst,
-						  smp_processor_id());
+						  raw_smp_processor_id());
 		/* Program the pwrdm desired target state */
 		ret = arch_pwrdm->pwrdm_set_next_pwrst(pwrdm, pwrst);
 	}