6.6-stable review patch. If anyone has any objections, please let me know.
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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.169528612... 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; }