linux-kernel - [PATCH] clocksource: fix clocksource_mmio_readX

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]

Message-ID: <1397726874-6349-1-git-send-email-Li.Xiubo@freescale.com>
Date:	Thu, 17 Apr 2014 17:27:54 +0800
From:	Xiubo Li <Li.Xiubo@...escale.com>
To:	<daniel.lezcano@...aro.org>, <tglx@...utronix.de>
CC:	<linux-kernel@...r.kernel.org>, Xiubo Li <Li.Xiubo@...escale.com>
Subject: [PATCH] clocksource: fix clocksource_mmio_readX_down

For some clocksource devices, for example, the registers are 32-bit, while
the lower 16-bit is used for timer counting(And reading the upper 16-bit
will return 0).

For example, when the counter value is 0x00001111, and then the
~readl_relaxed(to_mmio_clksrc(c)->reg) will return the value of 0xFFFFEEEE,
but it should be 0x0000EEEE.

So just using the c->mask to mask the unused bits.

Signed-off-by: Xiubo Li <Li.Xiubo@...escale.com>
---
 drivers/clocksource/mmio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c
index c0e2512..f17a0d1 100644
--- a/drivers/clocksource/mmio.c
+++ b/drivers/clocksource/mmio.c
@@ -27,7 +27,7 @@ cycle_t clocksource_mmio_readl_up(struct clocksource *c)
 
 cycle_t clocksource_mmio_readl_down(struct clocksource *c)
 {
-	return ~readl_relaxed(to_mmio_clksrc(c)->reg);
+	return ~readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
 }
 
 cycle_t clocksource_mmio_readw_up(struct clocksource *c)
@@ -37,7 +37,7 @@ cycle_t clocksource_mmio_readw_up(struct clocksource *c)
 
 cycle_t clocksource_mmio_readw_down(struct clocksource *c)
 {
-	return ~(unsigned)readw_relaxed(to_mmio_clksrc(c)->reg);
+	return ~(unsigned)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
 }
 
 /**
-- 
1.8.4


--
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/