linux-kernel - [PATCH 1/2] clocksource: dbx500-prcmu: use relaxed readl variant

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-next>] [day] [month] [year] [list]

Date:	Mon, 21 Jan 2013 13:09:31 +0100
From:	Fabio Baltieri <fabio.baltieri@...aro.org>
To:	Linus Walleij <linus.walleij@...aro.org>,
	John Stultz <johnstul@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Rabin Vincent <rabin.vincent@...ricsson.com>,
	Fabio Baltieri <fabio.baltieri@...aro.org>
Subject: [PATCH 1/2] clocksource: dbx500-prcmu: use relaxed readl variant

From: Rabin Vincent <rabin.vincent@...ricsson.com>

Modify clksrc_dbx500_prcmu_read to replace readl() with readl_relaxed().
This speeds up calls to the function by about 40%.

Signed-off-by: Rabin Vincent <rabin.vincent@...ricsson.com>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Fabio Baltieri <fabio.baltieri@...aro.org>
---
 drivers/clocksource/clksrc-dbx500-prcmu.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/clksrc-dbx500-prcmu.c b/drivers/clocksource/clksrc-dbx500-prcmu.c
index c26c369..159f54a 100644
--- a/drivers/clocksource/clksrc-dbx500-prcmu.c
+++ b/drivers/clocksource/clksrc-dbx500-prcmu.c
@@ -33,15 +33,14 @@
 
 static void __iomem *clksrc_dbx500_timer_base;
 
-static cycle_t clksrc_dbx500_prcmu_read(struct clocksource *cs)
+static cycle_t notrace clksrc_dbx500_prcmu_read(struct clocksource *cs)
 {
+	void __iomem *base = clksrc_dbx500_timer_base;
 	u32 count, count2;
 
 	do {
-		count = readl(clksrc_dbx500_timer_base +
-			      PRCMU_TIMER_DOWNCOUNT);
-		count2 = readl(clksrc_dbx500_timer_base +
-			       PRCMU_TIMER_DOWNCOUNT);
+		count = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT);
+		count2 = readl_relaxed(base + PRCMU_TIMER_DOWNCOUNT);
 	} while (count2 != count);
 
 	/* Negate because the timer is a decrementing counter */
-- 
1.7.12.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/