linux-kernel - [PATCH v2 05/19] PM / devfreq: tegra: Replace write memory barrier with the read barrier

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: <20190415145505.18397-6-digetx@gmail.com>
Date:   Mon, 15 Apr 2019 17:54:51 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc:     linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: [PATCH v2 05/19] PM / devfreq: tegra: Replace write memory barrier with the read barrier

The write memory barrier isn't needed because the BUS buffer is flushed
by read after write that happens after the removed wmb(), we will also
use readl() instead of the relaxed version to ensure that read is indeed
completed.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/devfreq/tegra-devfreq.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index d62fb1b0d9bb..f0f0d78f6cbf 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -243,8 +243,7 @@ static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
 static void actmon_write_barrier(struct tegra_devfreq *tegra)
 {
 	/* ensure the update has reached the ACTMON */
-	wmb();
-	actmon_readl(tegra, ACTMON_GLB_STATUS);
+	readl(tegra->regs + ACTMON_GLB_STATUS);
 }
 
 static void actmon_isr_device(struct tegra_devfreq *tegra,
-- 
2.21.0