diff mbox series

[v3] PM: Fix symbol export for _SIMPLE_ variants of _PM_OPS()

Message ID 20230920084121.14131-1-raag.jadav@intel.com
State New
Headers
Series [v3] PM: Fix symbol export for _SIMPLE_ variants of _PM_OPS() |

Commit Message

Raag Jadav Sept. 20, 2023, 8:41 a.m. UTC 
  Currently EXPORT_*_SIMPLE_DEV_PM_OPS() use EXPORT_*_DEV_PM_OPS() set
of macros to export dev_pm_ops symbol, which export the symbol in case
CONFIG_PM=y but don't take CONFIG_PM_SLEEP into consideration.

Since _SIMPLE_ variants of _PM_OPS() do not include runtime PM handles
and are only used in case CONFIG_PM_SLEEP=y, we should not be exporting
their dev_pm_ops symbol in case CONFIG_PM_SLEEP=n.

This can be fixed by having two distinct set of export macros for both
_RUNTIME_ and _SIMPLE_ variants of _PM_OPS(), such that the export of
dev_pm_ops symbol used in each variant depends on CONFIG_PM and
CONFIG_PM_SLEEP respectively.

Introduce _DEV_SLEEP_PM_OPS() set of export macros for _SIMPLE_ variants
of _PM_OPS(), which export dev_pm_ops symbol only in case CONFIG_PM_SLEEP=y
and discard it otherwise.

Fixes: 34e1ed189fab ("PM: Improve EXPORT_*_DEV_PM_OPS macros")
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
---
PS: This is a standalone fix and works without updating any drivers.

Changes since v2:
- Drop redundant patches

Changes since v1:
- Update drivers to new set of macros

 include/linux/pm.h | 43 +++++++++++++++++++++++++++++--------------
 1 file changed, 29 insertions(+), 14 deletions(-)

Comments

Raag Jadav Sept. 20, 2023, 9:33 a.m. UTC | #1 
On Wed, Sep 20, 2023 at 10:53:23AM +0200, Paul Cercueil wrote:
> Le mercredi 20 septembre 2023 à 14:11 +0530, Raag Jadav a écrit :
> > Currently EXPORT_*_SIMPLE_DEV_PM_OPS() use EXPORT_*_DEV_PM_OPS() set
> > of macros to export dev_pm_ops symbol, which export the symbol in
> > case
> > CONFIG_PM=y but don't take CONFIG_PM_SLEEP into consideration.
> > 
> > Since _SIMPLE_ variants of _PM_OPS() do not include runtime PM
> > handles
> > and are only used in case CONFIG_PM_SLEEP=y, we should not be
> > exporting
> > their dev_pm_ops symbol in case CONFIG_PM_SLEEP=n.
> > 
> > This can be fixed by having two distinct set of export macros for
> > both
> > _RUNTIME_ and _SIMPLE_ variants of _PM_OPS(), such that the export of
> > dev_pm_ops symbol used in each variant depends on CONFIG_PM and
> > CONFIG_PM_SLEEP respectively.
> > 
> > Introduce _DEV_SLEEP_PM_OPS() set of export macros for _SIMPLE_
> > variants
> > of _PM_OPS(), which export dev_pm_ops symbol only in case
> > CONFIG_PM_SLEEP=y
> > and discard it otherwise.
> > 
> > Fixes: 34e1ed189fab ("PM: Improve EXPORT_*_DEV_PM_OPS macros")
> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > ---
> > PS: This is a standalone fix and works without updating any drivers.
> 
> I had to double-check that, to make sure that none of the drivers using
> these macros also use pm_ptr() instead of pm_sleep_ptr() to access the
> exported dev_pm_ops.
> 
> I did not check extensively but everything seems to use pm_sleep_ptr(),
> so it looks safe enough.

I have tested it against -rc2 without any problems.

> > Changes since v2:
> > - Drop redundant patches
> > 
> > Changes since v1:
> > - Update drivers to new set of macros
> > 
> >  include/linux/pm.h | 43 +++++++++++++++++++++++++++++--------------
> >  1 file changed, 29 insertions(+), 14 deletions(-)
> > 
> > diff --git a/include/linux/pm.h b/include/linux/pm.h
> > index 1400c37b29c7..99a8146fa479 100644
> > --- a/include/linux/pm.h
> > +++ b/include/linux/pm.h
> > @@ -374,24 +374,39 @@ const struct dev_pm_ops name = { \
> >         RUNTIME_PM_OPS(runtime_suspend_fn, runtime_resume_fn,
> > idle_fn) \
> >  }
> >  
> > -#ifdef CONFIG_PM
> > -#define _EXPORT_DEV_PM_OPS(name, license,
> > ns)                          \
> > +#define _EXPORT_PM_OPS(name, license,
> > ns)                              \
> >         const struct dev_pm_ops
> > name;                                   \
> >         __EXPORT_SYMBOL(name, license,
> > ns);                             \
> >         const struct dev_pm_ops name
> > -#define EXPORT_PM_FN_GPL(name)         EXPORT_SYMBOL_GPL(name)
> > -#define EXPORT_PM_FN_NS_GPL(name, ns)  EXPORT_SYMBOL_NS_GPL(name,
> > ns)
> > -#else
> > -#define _EXPORT_DEV_PM_OPS(name, license,
> > ns)                          \
> > +
> > +#define _PM_OPS(name, license,
> 
> This macro creates a dev_pm_ops that's meant to be garbage-collected by
> the compiler; so maybe name it _USELESS_PM_OPS() or something like
> that.

_USELESS_PM_OPS() sounds a bit heavy handed ;)
Gives the impression that the macro itelf is not used anywhere in code.

Something like _DISCARD_PM_OPS() makes more sense.

Raag
Raag Jadav Sept. 20, 2023, 12:07 p.m. UTC | #2 
On Wed, Sep 20, 2023 at 12:00:05PM +0200, Paul Cercueil wrote:
> Le mercredi 20 septembre 2023 à 12:33 +0300, Raag Jadav a écrit :
> > On Wed, Sep 20, 2023 at 10:53:23AM +0200, Paul Cercueil wrote:
> > > Le mercredi 20 septembre 2023 à 14:11 +0530, Raag Jadav a écrit :
> > > > Currently EXPORT_*_SIMPLE_DEV_PM_OPS() use EXPORT_*_DEV_PM_OPS()
> > > > set
> > > > of macros to export dev_pm_ops symbol, which export the symbol in
> > > > case
> > > > CONFIG_PM=y but don't take CONFIG_PM_SLEEP into consideration.
> > > > 
> > > > Since _SIMPLE_ variants of _PM_OPS() do not include runtime PM
> > > > handles
> > > > and are only used in case CONFIG_PM_SLEEP=y, we should not be
> > > > exporting
> > > > their dev_pm_ops symbol in case CONFIG_PM_SLEEP=n.
> > > > 
> > > > This can be fixed by having two distinct set of export macros for
> > > > both
> > > > _RUNTIME_ and _SIMPLE_ variants of _PM_OPS(), such that the
> > > > export of
> > > > dev_pm_ops symbol used in each variant depends on CONFIG_PM and
> > > > CONFIG_PM_SLEEP respectively.
> > > > 
> > > > Introduce _DEV_SLEEP_PM_OPS() set of export macros for _SIMPLE_
> > > > variants
> > > > of _PM_OPS(), which export dev_pm_ops symbol only in case
> > > > CONFIG_PM_SLEEP=y
> > > > and discard it otherwise.
> > > > 
> > > > Fixes: 34e1ed189fab ("PM: Improve EXPORT_*_DEV_PM_OPS macros")
> > > > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > > > ---
> > > > PS: This is a standalone fix and works without updating any
> > > > drivers.
> > > 
> > > I had to double-check that, to make sure that none of the drivers
> > > using
> > > these macros also use pm_ptr() instead of pm_sleep_ptr() to access
> > > the
> > > exported dev_pm_ops.
> > > 
> > > I did not check extensively but everything seems to use
> > > pm_sleep_ptr(),
> > > so it looks safe enough.
> > 
> > I have tested it against -rc2 without any problems.
> 
> You'd need to test an "allyesconfig" with CONFIG_PM=y, and
> CONFIG_PM_SLEEP disabled. Is that what you tested?

Yes, and also validated *.symvers if dev_pm_ops symbol is really discarded.

Seems to work as expected.

Raag
diff mbox series

Patch

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 1400c37b29c7..99a8146fa479 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -374,24 +374,39 @@  const struct dev_pm_ops name = { \
 	RUNTIME_PM_OPS(runtime_suspend_fn, runtime_resume_fn, idle_fn) \
 }
 
-#ifdef CONFIG_PM
-#define _EXPORT_DEV_PM_OPS(name, license, ns)				\
+#define _EXPORT_PM_OPS(name, license, ns)				\
 	const struct dev_pm_ops name;					\
 	__EXPORT_SYMBOL(name, license, ns);				\
 	const struct dev_pm_ops name
-#define EXPORT_PM_FN_GPL(name)		EXPORT_SYMBOL_GPL(name)
-#define EXPORT_PM_FN_NS_GPL(name, ns)	EXPORT_SYMBOL_NS_GPL(name, ns)
-#else
-#define _EXPORT_DEV_PM_OPS(name, license, ns)				\
+
+#define _PM_OPS(name, license, ns)					\
 	static __maybe_unused const struct dev_pm_ops __static_##name
+
+#ifdef CONFIG_PM
+#define _EXPORT_DEV_PM_OPS(name, license, ns)		_EXPORT_PM_OPS(name, license, ns)
+#define EXPORT_PM_FN_GPL(name)				EXPORT_SYMBOL_GPL(name)
+#define EXPORT_PM_FN_NS_GPL(name, ns)			EXPORT_SYMBOL_NS_GPL(name, ns)
+#else
+#define _EXPORT_DEV_PM_OPS(name, license, ns)		_PM_OPS(name, license, ns)
 #define EXPORT_PM_FN_GPL(name)
 #define EXPORT_PM_FN_NS_GPL(name, ns)
 #endif
 
-#define EXPORT_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "", "")
-#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "GPL", "")
-#define EXPORT_NS_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "", #ns)
-#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "GPL", #ns)
+#ifdef CONFIG_PM_SLEEP
+#define _EXPORT_DEV_SLEEP_PM_OPS(name, license, ns)	_EXPORT_PM_OPS(name, license, ns)
+#else
+#define _EXPORT_DEV_SLEEP_PM_OPS(name, license, ns)	_PM_OPS(name, license, ns)
+#endif
+
+#define EXPORT_DEV_PM_OPS(name)				_EXPORT_DEV_PM_OPS(name, "", "")
+#define EXPORT_GPL_DEV_PM_OPS(name)			_EXPORT_DEV_PM_OPS(name, "GPL", "")
+#define EXPORT_NS_DEV_PM_OPS(name, ns)			_EXPORT_DEV_PM_OPS(name, "", #ns)
+#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns)		_EXPORT_DEV_PM_OPS(name, "GPL", #ns)
+
+#define EXPORT_DEV_SLEEP_PM_OPS(name)			_EXPORT_DEV_SLEEP_PM_OPS(name, "", "")
+#define EXPORT_GPL_DEV_SLEEP_PM_OPS(name)		_EXPORT_DEV_SLEEP_PM_OPS(name, "GPL", "")
+#define EXPORT_NS_DEV_SLEEP_PM_OPS(name, ns)		_EXPORT_DEV_SLEEP_PM_OPS(name, "", #ns)
+#define EXPORT_NS_GPL_DEV_SLEEP_PM_OPS(name, ns)	_EXPORT_DEV_SLEEP_PM_OPS(name, "GPL", #ns)
 
 /*
  * Use this if you want to use the same suspend and resume callbacks for suspend
@@ -404,19 +419,19 @@  const struct dev_pm_ops name = { \
 	_DEFINE_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL)
 
 #define EXPORT_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
-	EXPORT_DEV_PM_OPS(name) = { \
+	EXPORT_DEV_SLEEP_PM_OPS(name) = { \
 		SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 	}
 #define EXPORT_GPL_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
-	EXPORT_GPL_DEV_PM_OPS(name) = { \
+	EXPORT_GPL_DEV_SLEEP_PM_OPS(name) = { \
 		SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 	}
 #define EXPORT_NS_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn, ns)	\
-	EXPORT_NS_DEV_PM_OPS(name, ns) = { \
+	EXPORT_NS_DEV_SLEEP_PM_OPS(name, ns) = { \
 		SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 	}
 #define EXPORT_NS_GPL_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn, ns)	\
-	EXPORT_NS_GPL_DEV_PM_OPS(name, ns) = { \
+	EXPORT_NS_GPL_DEV_SLEEP_PM_OPS(name, ns) = { \
 		SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 	}