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* [PATCH] watchdog: coh901327: add COMMON_CLK dependency
@ 2020-12-03 22:33 Arnd Bergmann
  2020-12-04  1:41 ` Guenter Roeck
  2020-12-10 23:00 ` Nick Desaulniers
  0 siblings, 2 replies; 4+ messages in thread
From: Arnd Bergmann @ 2020-12-03 22:33 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Nathan Chancellor, Nick Desaulniers
  Cc: Arnd Bergmann, linux-watchdog, linux-kernel, clang-built-linux

From: Arnd Bergmann <arnd@arndb.de>

clang produces a build failure in configurations without COMMON_CLK
when a timeout calculation goes wrong:

arm-linux-gnueabi-ld: drivers/watchdog/coh901327_wdt.o: in function `coh901327_enable':
coh901327_wdt.c:(.text+0x50): undefined reference to `__bad_udelay'

Add a Kconfig dependency to only do build testing when COMMON_CLK
is enabled.

Fixes: da2a68b3eb47 ("watchdog: Enable COMPILE_TEST where possible")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/watchdog/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 8bdbd125821b..32fa6de7b820 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -631,7 +631,7 @@ config SUNXI_WATCHDOG
 
 config COH901327_WATCHDOG
 	bool "ST-Ericsson COH 901 327 watchdog"
-	depends on ARCH_U300 || (ARM && COMPILE_TEST)
+	depends on ARCH_U300 || (ARM && COMMON_CLK && COMPILE_TEST)
 	default y if MACH_U300
 	select WATCHDOG_CORE
 	help
-- 
2.27.0


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] watchdog: coh901327: add COMMON_CLK dependency
  2020-12-03 22:33 [PATCH] watchdog: coh901327: add COMMON_CLK dependency Arnd Bergmann
@ 2020-12-04  1:41 ` Guenter Roeck
  2020-12-10 23:00 ` Nick Desaulniers
  1 sibling, 0 replies; 4+ messages in thread
From: Guenter Roeck @ 2020-12-04  1:41 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Wim Van Sebroeck, Nathan Chancellor, Nick Desaulniers,
	Arnd Bergmann, linux-watchdog, linux-kernel, clang-built-linux

On Thu, Dec 03, 2020 at 11:33:42PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> clang produces a build failure in configurations without COMMON_CLK
> when a timeout calculation goes wrong:
> 
> arm-linux-gnueabi-ld: drivers/watchdog/coh901327_wdt.o: in function `coh901327_enable':
> coh901327_wdt.c:(.text+0x50): undefined reference to `__bad_udelay'
> 
> Add a Kconfig dependency to only do build testing when COMMON_CLK
> is enabled.
> 
> Fixes: da2a68b3eb47 ("watchdog: Enable COMPILE_TEST where possible")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 8bdbd125821b..32fa6de7b820 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -631,7 +631,7 @@ config SUNXI_WATCHDOG
>  
>  config COH901327_WATCHDOG
>  	bool "ST-Ericsson COH 901 327 watchdog"
> -	depends on ARCH_U300 || (ARM && COMPILE_TEST)
> +	depends on ARCH_U300 || (ARM && COMMON_CLK && COMPILE_TEST)
>  	default y if MACH_U300
>  	select WATCHDOG_CORE
>  	help
> -- 
> 2.27.0
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] watchdog: coh901327: add COMMON_CLK dependency
  2020-12-03 22:33 [PATCH] watchdog: coh901327: add COMMON_CLK dependency Arnd Bergmann
  2020-12-04  1:41 ` Guenter Roeck
@ 2020-12-10 23:00 ` Nick Desaulniers
  2020-12-11  0:16   ` Guenter Roeck
  1 sibling, 1 reply; 4+ messages in thread
From: Nick Desaulniers @ 2020-12-10 23:00 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Wim Van Sebroeck, Guenter Roeck, Nathan Chancellor,
	Arnd Bergmann, linux-watchdog, LKML, clang-built-linux

On Thu, Dec 3, 2020 at 2:34 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> clang produces a build failure in configurations without COMMON_CLK
> when a timeout calculation goes wrong:
>
> arm-linux-gnueabi-ld: drivers/watchdog/coh901327_wdt.o: in function `coh901327_enable':
> coh901327_wdt.c:(.text+0x50): undefined reference to `__bad_udelay'

Isn't a linkage failure against __bad_udelay supposed to be
interpreted as a value too large being passed to udelay()? IIRC, this
was an issue for someone building an Apple touchpad driver with Clang
at -O3...you sent a fix for that:
https://github.com/ClangBuiltLinux/linux/issues/678,
https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git/commit/?id=fff2d0f701e6753591609739f8ab9be1c8e80ebb.

>
> Add a Kconfig dependency to only do build testing when COMMON_CLK
> is enabled.
>
> Fixes: da2a68b3eb47 ("watchdog: Enable COMPILE_TEST where possible")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/watchdog/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 8bdbd125821b..32fa6de7b820 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -631,7 +631,7 @@ config SUNXI_WATCHDOG
>
>  config COH901327_WATCHDOG
>         bool "ST-Ericsson COH 901 327 watchdog"
> -       depends on ARCH_U300 || (ARM && COMPILE_TEST)
> +       depends on ARCH_U300 || (ARM && COMMON_CLK && COMPILE_TEST)
>         default y if MACH_U300
>         select WATCHDOG_CORE
>         help
> --
> 2.27.0
>


-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] watchdog: coh901327: add COMMON_CLK dependency
  2020-12-10 23:00 ` Nick Desaulniers
@ 2020-12-11  0:16   ` Guenter Roeck
  0 siblings, 0 replies; 4+ messages in thread
From: Guenter Roeck @ 2020-12-11  0:16 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Arnd Bergmann, Wim Van Sebroeck, Nathan Chancellor,
	Arnd Bergmann, linux-watchdog, LKML, clang-built-linux

On Thu, Dec 10, 2020 at 03:00:30PM -0800, Nick Desaulniers wrote:
> On Thu, Dec 3, 2020 at 2:34 PM Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > clang produces a build failure in configurations without COMMON_CLK
> > when a timeout calculation goes wrong:
> >
> > arm-linux-gnueabi-ld: drivers/watchdog/coh901327_wdt.o: in function `coh901327_enable':
> > coh901327_wdt.c:(.text+0x50): undefined reference to `__bad_udelay'
> 
> Isn't a linkage failure against __bad_udelay supposed to be
> interpreted as a value too large being passed to udelay()? IIRC, this
> was an issue for someone building an Apple touchpad driver with Clang
> at -O3...you sent a fix for that:
> https://github.com/ClangBuiltLinux/linux/issues/678,
> https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git/commit/?id=fff2d0f701e6753591609739f8ab9be1c8e80ebb.

The problem is likely that clk_get_rate() returns a constant 0,
which in the real world would end up in a divide by 0 crash.
An alternative might be be to add

	freq = clk_get_rate(clk);
-->	if (freq == 0)
-->		return;

but I don't know if that would really be worth the effort.
I prefer the current fix.

Guenter

> 
> >
> > Add a Kconfig dependency to only do build testing when COMMON_CLK
> > is enabled.
> >
> > Fixes: da2a68b3eb47 ("watchdog: Enable COMPILE_TEST where possible")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >  drivers/watchdog/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 8bdbd125821b..32fa6de7b820 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -631,7 +631,7 @@ config SUNXI_WATCHDOG
> >
> >  config COH901327_WATCHDOG
> >         bool "ST-Ericsson COH 901 327 watchdog"
> > -       depends on ARCH_U300 || (ARM && COMPILE_TEST)
> > +       depends on ARCH_U300 || (ARM && COMMON_CLK && COMPILE_TEST)
> >         default y if MACH_U300
> >         select WATCHDOG_CORE
> >         help
> > --
> > 2.27.0
> >
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-12-03 22:33 [PATCH] watchdog: coh901327: add COMMON_CLK dependency Arnd Bergmann
2020-12-04  1:41 ` Guenter Roeck
2020-12-10 23:00 ` Nick Desaulniers
2020-12-11  0:16   ` Guenter Roeck

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