Messages in this thread | | | Date | Thu, 26 Oct 2023 10:17:52 -0700 | From | Darren Hart <> | Subject | Re: [PATCH] sbsa_gwdt: Calculate timeout with 64-bit math |
| |
On Sun, Oct 22, 2023 at 09:58:26AM -0700, Guenter Roeck wrote: > On 10/14/23 02:12, Darren Hart wrote: > > On Tue, Sep 26, 2023 at 05:45:13AM -0700, Guenter Roeck wrote: > > > On Thu, Sep 21, 2023 at 02:02:36AM -0700, Darren Hart wrote: > > > > 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> > > > > Guenter or Wim, I haven't seen this land in the RCs or in next yet. Have > > you already picked it up? Anything more needed from me? > > > > Thanks, > > > > Sorry, I am suffering from what I can only describe as a severe case of > maintainer/reviewer PTSD, and I have yet to find a way of dealing with that. >
I'm sorry to hear it Guenter, it can be a thankless slog of a treadmill sometimes. I found having a co-maintainer a huge help to even out the human factors while maintaining the x86 platform drivers (in the before times).
In the short term, should I ask if one of the Arm maintainers would be willing to pick this patch up?
Thanks,
-- Darren Hart Ampere Computing / Linux Enabling
| |