From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
patches@lists.linux.dev,
Vanshidhar Konda <vanshikonda@os.amperecomputing.com>,
Darren Hart <darren@os.amperecomputing.com>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>,
linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 6.6 442/530] sbsa_gwdt: Calculate timeout with 64-bit math
Date: Fri, 24 Nov 2023 17:50:08 +0000 [thread overview]
Message-ID: <20231124172041.551376645@linuxfoundation.org> (raw)
In-Reply-To: <20231124172028.107505484@linuxfoundation.org>
6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Darren Hart <darren@os.amperecomputing.com>
commit 5d6aa89bba5bd6af2580f872b57f438dab883738 upstream.
Commit abd3ac7902fb ("watchdog: sbsa: Support architecture version 1")
introduced new timer math for watchdog revision 1 with the 48 bit offset
register.
The gwdt->clk and timeout are u32, but the argument being calculated is
u64. Without a cast, the compiler performs u32 operations, truncating
intermediate steps, resulting in incorrect values.
A watchdog revision 1 implementation with a gwdt->clk of 1GHz and a
timeout of 600s writes 3647256576 to the one shot watchdog instead of
300000000000, resulting in the watchdog firing in 3.6s instead of 600s.
Force u64 math by casting the first argument (gwdt->clk) as a u64. Make
the order of operations explicit with parenthesis.
Fixes: abd3ac7902fb ("watchdog: sbsa: Support architecture version 1")
Reported-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Signed-off-by: Darren Hart <darren@os.amperecomputing.com>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: <stable@vger.kernel.org> # 5.14.x
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/7d1713c5ffab19b0f3de796d82df19e8b1f340de.1695286124.git.darren@os.amperecomputing.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/watchdog/sbsa_gwdt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/watchdog/sbsa_gwdt.c
+++ b/drivers/watchdog/sbsa_gwdt.c
@@ -152,14 +152,14 @@ static int sbsa_gwdt_set_timeout(struct
timeout = clamp_t(unsigned int, timeout, 1, wdd->max_hw_heartbeat_ms / 1000);
if (action)
- sbsa_gwdt_reg_write(gwdt->clk * timeout, gwdt);
+ sbsa_gwdt_reg_write((u64)gwdt->clk * timeout, gwdt);
else
/*
* In the single stage mode, The first signal (WS0) is ignored,
* the timeout is (WOR * 2), so the WOR should be configured
* to half value of timeout.
*/
- sbsa_gwdt_reg_write(gwdt->clk / 2 * timeout, gwdt);
+ sbsa_gwdt_reg_write(((u64)gwdt->clk / 2) * timeout, gwdt);
return 0;
}
parent reply other threads:[~2023-11-24 18:21 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20231124172028.107505484@linuxfoundation.org>]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231124172041.551376645@linuxfoundation.org \
--to=gregkh@linuxfoundation.org \
--cc=darren@os.amperecomputing.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=linux@roeck-us.net \
--cc=patches@lists.linux.dev \
--cc=stable@vger.kernel.org \
--cc=vanshikonda@os.amperecomputing.com \
--cc=wim@linux-watchdog.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).