Messages in this thread | | | Subject | Re: [PATCH v2] arch/powerpc: Rework local_paca to avoid LTO warnings | From | Christophe Leroy <> | Date | Thu, 14 Mar 2019 06:46:13 +0100 |
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Le 14/03/2019 à 03:31, Alastair D'Silva a écrit : > From: Alastair D'Silva <alastair@d-silva.org> > > When building an LTO kernel, the existing code generates warnings: > ./arch/powerpc/include/asm/paca.h:37:30: warning: register of > ‘local_paca’ used for multiple global register variables > register struct paca_struct *local_paca asm("r13"); > ^ > ./arch/powerpc/include/asm/paca.h:37:30: note: conflicts with > ‘local_paca’ > > This patch reworks local_paca into an inline getter & setter function, > which addresses the warning. > > Changelog: > V2 > - Address whitespace issues > - keep new implementation close to where the old implementation was > > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> --- > arch/powerpc/include/asm/paca.h | 37 +++++++++++++++++++++++++-------- > arch/powerpc/kernel/paca.c | 2 +- > 2 files changed, 29 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h > index e843bc5d1a0f..2fa0b43357c9 100644 > --- a/arch/powerpc/include/asm/paca.h > +++ b/arch/powerpc/include/asm/paca.h > @@ -34,19 +34,38 @@ > #include <asm/cpuidle.h> > #include <asm/atomic.h> > > -register struct paca_struct *local_paca asm("r13"); > - > #if defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_SMP) > extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */ > -/* > - * Add standard checks that preemption cannot occur when using get_paca(): > - * otherwise the paca_struct it points to may be the wrong one just after. > - */ > -#define get_paca() ((void) debug_smp_processor_id(), local_paca) > -#else > -#define get_paca() local_paca > #endif > > +static inline struct paca_struct *get_paca_no_preempt_check(void) > +{ > + register struct paca_struct *paca asm("r13"); > + > + return paca; > +} > + > +static inline struct paca_struct *get_paca(void) > +{ > +#if defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_SMP) > + /* > + * Add standard checks that preemption cannot occur when using get_paca(): > + * otherwise the paca_struct it points to may be the wrong one just after. > + */ > + debug_smp_processor_id(); > +#endif > + return get_paca_no_preempt_check(); > +} > + > +#define local_paca get_paca_no_preempt_check() > + > +static inline void set_paca(struct paca_struct *new) > +{ > + register struct paca_struct *paca asm("r13"); > + > + paca = new; > +} > + > #ifdef CONFIG_PPC_PSERIES > #define get_lppaca() (get_paca()->lppaca_ptr) > #endif > diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c > index 913bfca09c4f..ae5c243f9d5a 100644 > --- a/arch/powerpc/kernel/paca.c > +++ b/arch/powerpc/kernel/paca.c > @@ -172,7 +172,7 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu) > void setup_paca(struct paca_struct *new_paca) > { > /* Setup r13 */ > - local_paca = new_paca; > + set_paca(new_paca); > > #ifdef CONFIG_PPC_BOOK3E > /* On Book3E, initialize the TLB miss exception frames */ >
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