| Message ID | 20201116090804.206286-1-u.kleine-koenig@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] pwm: keembay: Fix build failure with -Os | expand |
Hi Uwe, > From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > Sent: Monday, 16 November, 2020 5:08 PM > Subject: [PATCH RFC] pwm: keembay: Fix build failure with -Os > > The driver used this construct: > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > static inline void keembay_pwm_update_bits(struct keembay_pwm > *priv, u32 mask, > u32 val, u32 offset) > { > u32 buff = readl(priv->base + offset); > > buff = u32_replace_bits(buff, val, mask); > writel(buff, priv->base + offset); > } > > ... > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > KMB_PWM_LEADIN_OFFSET(pwm- > >hwpwm)); > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > triggers: > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm- > keembay.c:16: > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at > /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at > /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > > The compiler doesn't seem to be able to notice that with field being > 0x3ffffff the expression > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > __bad_mask(); > > can be optimized away. > > So use __always_inline and document the problem in a comment to fix > this. > > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Thank you for spending time in resolving this build failure. I shall prepare and share the next version of patch with your approach. > --- > Hello, > > I'm not sure this is the right fix. Maybe the bitfield stuff can be > changed somehow to make this problem go away, too? > > Best regards > Uwe > > drivers/pwm/pwm-keembay.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-keembay.c b/drivers/pwm/pwm-keembay.c > index 2b6dd070daa4..cdfdef66ff8e 100644 > --- a/drivers/pwm/pwm-keembay.c > +++ b/drivers/pwm/pwm-keembay.c > @@ -63,7 +63,12 @@ static int keembay_clk_enable(struct device *dev, > struct clk *clk) > return devm_add_action_or_reset(dev, keembay_clk_unprepare, clk); > } > > -static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 > mask, > +/* > + * With gcc 10, CONFIG_CC_OPTIMIZE_FOR_SIZE and only "inline" instead of > + * "__always_inline" this fails to compile because the compiler doesn't notice > + * for all valid masks (e.g. KMB_PWM_LEADIN_MASK) that they are ok. > + */ > +static __always_inline void keembay_pwm_update_bits(struct > keembay_pwm *priv, u32 mask, > u32 val, u32 offset) > { > u32 buff = readl(priv->base + offset); > -- > 2.28.0 Thanks, Vijay
On Tue, Nov 17, 2020 at 05:29:01PM +0000, Ayyathurai, Vijayakannan wrote: > Hi Uwe, > > > From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > Sent: Monday, 16 November, 2020 5:08 PM > > Subject: [PATCH RFC] pwm: keembay: Fix build failure with -Os > > > > The driver used this construct: > > > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > > > static inline void keembay_pwm_update_bits(struct keembay_pwm > > *priv, u32 mask, > > u32 val, u32 offset) > > { > > u32 buff = readl(priv->base + offset); > > > > buff = u32_replace_bits(buff, val, mask); > > writel(buff, priv->base + offset); > > } > > > > ... > > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > > KMB_PWM_LEADIN_OFFSET(pwm- > > >hwpwm)); > > > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > > triggers: > > > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm- > > keembay.c:16: > > In function ‘field_multiplier’, > > inlined from ‘keembay_pwm_update_bits’ at > > /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > 119 | __bad_mask(); > > | ^~~~~~~~~~~~ > > In function ‘field_multiplier’, > > inlined from ‘keembay_pwm_update_bits’ at > > /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > 119 | __bad_mask(); > > | ^~~~~~~~~~~~ > > > > The compiler doesn't seem to be able to notice that with field being > > 0x3ffffff the expression > > > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > > __bad_mask(); > > > > can be optimized away. > > > > So use __always_inline and document the problem in a comment to fix > > this. > > > > Reported-by: kernel test robot <lkp@intel.com> > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > Thank you for spending time in resolving this build failure. > > I shall prepare and share the next version of patch with your approach. I don't understand this last sentence. IMHO there is currently nothing you have to do for this problem. You can send an Ack however if you want to. Best regards Uwe
[Cc: += linux-pwm which I forgot for the initial submission] Hello, On Mon, Nov 16, 2020 at 10:08:04AM +0100, Uwe Kleine-König wrote: > The driver used this construct: > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask, > u32 val, u32 offset) > { > u32 buff = readl(priv->base + offset); > > buff = u32_replace_bits(buff, val, mask); > writel(buff, priv->base + offset); > } > > ... > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > KMB_PWM_LEADIN_OFFSET(pwm->hwpwm)); > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > triggers: > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm-keembay.c:16: > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > > The compiler doesn't seem to be able to notice that with field being > 0x3ffffff the expression > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > __bad_mask(); > > can be optimized away. > > So use __always_inline and document the problem in a comment to fix > this. > > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > I'm not sure this is the right fix. Maybe the bitfield stuff can be > changed somehow to make this problem go away, too? Note, this patch Fixes: cdbea243f419 ("pwm: Add PWM driver for Intel Keem Bay") so this isn't critical for v5.10. @thierry: If this is ok for you and Vijayakannan, you can squash this into the original commit. Best regards Uwe
Hi Thierry, > From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > Subject: Re: [PATCH RFC] pwm: keembay: Fix build failure with -Os > > [Cc: += linux-pwm which I forgot for the initial submission] > > Hello, > > On Mon, Nov 16, 2020 at 10:08:04AM +0100, Uwe Kleine-König wrote: > > The driver used this construct: > > > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > > > static inline void keembay_pwm_update_bits(struct keembay_pwm > *priv, u32 mask, > > u32 val, u32 offset) > > { > > u32 buff = readl(priv->base + offset); > > > > buff = u32_replace_bits(buff, val, mask); > > writel(buff, priv->base + offset); > > } > > > > ... > > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > > KMB_PWM_LEADIN_OFFSET(pwm- > >hwpwm)); > > > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > > triggers: > > > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm- > keembay.c:16: > > In function ‘field_multiplier’, > > inlined from ‘keembay_pwm_update_bits’ at > /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > 119 | __bad_mask(); > > | ^~~~~~~~~~~~ > > In function ‘field_multiplier’, > > inlined from ‘keembay_pwm_update_bits’ at > /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > 119 | __bad_mask(); > > | ^~~~~~~~~~~~ > > > > The compiler doesn't seem to be able to notice that with field being > > 0x3ffffff the expression > > > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > > __bad_mask(); > > > > can be optimized away. > > > > So use __always_inline and document the problem in a comment to fix > > this. > > > > Reported-by: kernel test robot <lkp@intel.com> > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > --- > > Hello, > > > > I'm not sure this is the right fix. Maybe the bitfield stuff can be > > changed somehow to make this problem go away, too? > > Note, this patch > > Fixes: cdbea243f419 ("pwm: Add PWM driver for Intel Keem Bay") > > so this isn't critical for v5.10. > > @thierry: If this is ok for you and Vijayakannan, you can squash this > into the original commit. > I am ok with Uwe approach. I have compiled the change and tested in Keembay board as well. > Best regards > Uwe > > -- > Pengutronix e.K. | Uwe Kleine-König | > Industrial Linux Solutions | https://www.pengutronix.de/ | Thanks, Vijay
On Mon, Nov 16, 2020 at 10:08:04AM +0100, Uwe Kleine-König wrote: > The driver used this construct: > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask, > u32 val, u32 offset) > { > u32 buff = readl(priv->base + offset); > > buff = u32_replace_bits(buff, val, mask); > writel(buff, priv->base + offset); > } > > ... > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > KMB_PWM_LEADIN_OFFSET(pwm->hwpwm)); > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > triggers: > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm-keembay.c:16: > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > In function ‘field_multiplier’, > inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask > 119 | __bad_mask(); > | ^~~~~~~~~~~~ > > The compiler doesn't seem to be able to notice that with field being > 0x3ffffff the expression > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > __bad_mask(); > > can be optimized away. > > So use __always_inline and document the problem in a comment to fix > this. > > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > I'm not sure this is the right fix. Maybe the bitfield stuff can be > changed somehow to make this problem go away, too? > > Best regards > Uwe > > drivers/pwm/pwm-keembay.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) Applied, thanks. Thierry
On Wed, Nov 18, 2020 at 05:41:57PM +0000, Ayyathurai, Vijayakannan wrote: > Hi Thierry, > > > From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > Subject: Re: [PATCH RFC] pwm: keembay: Fix build failure with -Os > > > > [Cc: += linux-pwm which I forgot for the initial submission] > > > > Hello, > > > > On Mon, Nov 16, 2020 at 10:08:04AM +0100, Uwe Kleine-König wrote: > > > The driver used this construct: > > > > > > #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) > > > > > > static inline void keembay_pwm_update_bits(struct keembay_pwm > > *priv, u32 mask, > > > u32 val, u32 offset) > > > { > > > u32 buff = readl(priv->base + offset); > > > > > > buff = u32_replace_bits(buff, val, mask); > > > writel(buff, priv->base + offset); > > > } > > > > > > ... > > > keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, > > > KMB_PWM_LEADIN_OFFSET(pwm- > > >hwpwm)); > > > > > > With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this > > > triggers: > > > > > > In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm- > > keembay.c:16: > > > In function ‘field_multiplier’, > > > inlined from ‘keembay_pwm_update_bits’ at > > /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: > > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > > 119 | __bad_mask(); > > > | ^~~~~~~~~~~~ > > > In function ‘field_multiplier’, > > > inlined from ‘keembay_pwm_update_bits’ at > > /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: > > > /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to > > ‘__bad_mask’ declared with attribute error: bad bitfield mask > > > 119 | __bad_mask(); > > > | ^~~~~~~~~~~~ > > > > > > The compiler doesn't seem to be able to notice that with field being > > > 0x3ffffff the expression > > > > > > if ((field | (field - 1)) & ((field | (field - 1)) + 1)) > > > __bad_mask(); > > > > > > can be optimized away. > > > > > > So use __always_inline and document the problem in a comment to fix > > > this. > > > > > > Reported-by: kernel test robot <lkp@intel.com> > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > > --- > > > Hello, > > > > > > I'm not sure this is the right fix. Maybe the bitfield stuff can be > > > changed somehow to make this problem go away, too? > > > > Note, this patch > > > > Fixes: cdbea243f419 ("pwm: Add PWM driver for Intel Keem Bay") > > > > so this isn't critical for v5.10. > > > > @thierry: If this is ok for you and Vijayakannan, you can squash this > > into the original commit. > > > > I am ok with Uwe approach. > I have compiled the change and tested in Keembay board as well. I'll take that as a Tested-by. Next time, if you go through the trouble of testing a patch, make sure to reply with a: Tested-by: Your Name <your@email.com> So that patchwork can pick that up and credit you for it. Thierry
diff --git a/drivers/pwm/pwm-keembay.c b/drivers/pwm/pwm-keembay.c index 2b6dd070daa4..cdfdef66ff8e 100644 --- a/drivers/pwm/pwm-keembay.c +++ b/drivers/pwm/pwm-keembay.c @@ -63,7 +63,12 @@ static int keembay_clk_enable(struct device *dev, struct clk *clk) return devm_add_action_or_reset(dev, keembay_clk_unprepare, clk); } -static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask, +/* + * With gcc 10, CONFIG_CC_OPTIMIZE_FOR_SIZE and only "inline" instead of + * "__always_inline" this fails to compile because the compiler doesn't notice + * for all valid masks (e.g. KMB_PWM_LEADIN_MASK) that they are ok. + */ +static __always_inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask, u32 val, u32 offset) { u32 buff = readl(priv->base + offset);
The driver used this construct: #define KMB_PWM_LEADIN_MASK GENMASK(30, 0) static inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask, u32 val, u32 offset) { u32 buff = readl(priv->base + offset); buff = u32_replace_bits(buff, val, mask); writel(buff, priv->base + offset); } ... keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0, KMB_PWM_LEADIN_OFFSET(pwm->hwpwm)); With CONFIG_CC_OPTIMIZE_FOR_SIZE the compiler (here: gcc 10.2.0) this triggers: In file included from /home/uwe/gsrc/linux/drivers/pwm/pwm-keembay.c:16: In function ‘field_multiplier’, inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:124:17: /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask 119 | __bad_mask(); | ^~~~~~~~~~~~ In function ‘field_multiplier’, inlined from ‘keembay_pwm_update_bits’ at /home/uwe/gsrc/linux/include/linux/bitfield.h:154:1: /home/uwe/gsrc/linux/include/linux/bitfield.h:119:3: error: call to ‘__bad_mask’ declared with attribute error: bad bitfield mask 119 | __bad_mask(); | ^~~~~~~~~~~~ The compiler doesn't seem to be able to notice that with field being 0x3ffffff the expression if ((field | (field - 1)) & ((field | (field - 1)) + 1)) __bad_mask(); can be optimized away. So use __always_inline and document the problem in a comment to fix this. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- Hello, I'm not sure this is the right fix. Maybe the bitfield stuff can be changed somehow to make this problem go away, too? Best regards Uwe drivers/pwm/pwm-keembay.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)