linux-kernel - [PATCH 09/14] PM: domains: Fixup QoS latency measurements for IRQ safe devices in genpd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220511145704.698189-10-ulf.hansson@linaro.org>
Date:   Wed, 11 May 2022 16:56:59 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Maulik Shah <quic_mkshah@...cinc.com>,
        Gabriel Fernandez <gabriel.fernandez@...s.st.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Dmitry Osipenko <digetx@...il.com>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 09/14] PM: domains: Fixup QoS latency measurements for IRQ safe devices in genpd

When an IRQ safe device is attached to a non-IRQ safe PM domain, genpd
needs to prevent the PM domain from being powered off. However, genpd still
allows the device to be runtime suspended/resumed, hence it's also
reasonable to think that a governor may be used to validate the QoS latency
constraints.

Unfortunately, genpd_runtime_resume() treats the configuration above, as a
reason to skip measuring the QoS resume latency for the device. This is a
legacy behaviour that was earlier correct, but should have been changed
when genpd was transformed into its current behaviour around how it manages
IRQ safe devices. Luckily, there's no report about problems, so let's just
fixup the behaviour.

Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/base/power/domain.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 2cdfbe48dde0..48101232fcb9 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -970,10 +970,8 @@ static int genpd_runtime_resume(struct device *dev)
 	 * As we don't power off a non IRQ safe domain, which holds
 	 * an IRQ safe device, we don't need to restore power to it.
 	 */
-	if (irq_safe_dev_in_sleep_domain(dev, genpd)) {
-		timed = false;
+	if (irq_safe_dev_in_sleep_domain(dev, genpd))
 		goto out;
-	}

 	genpd_lock(genpd);
 	ret = genpd_power_on(genpd, 0);
-- 
2.25.1