From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751253AbcFCBdQ (ORCPT ); Thu, 2 Jun 2016 21:33:16 -0400 Received: from gate.crashing.org ([63.228.1.57]:50569 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750957AbcFCBdP (ORCPT ); Thu, 2 Jun 2016 21:33:15 -0400 Message-ID: <1464917520.26773.11.camel@kernel.crashing.org> Subject: Re: [PATCH v5 1/6] qspinlock: powerpc support qspinlock From: Benjamin Herrenschmidt To: Pan Xinhui , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.orgv, virtualization@lists.linux-foundation.org Cc: paulus@samba.org, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, paulmck@linux.vnet.ibm.com, waiman.long@hpe.com Date: Fri, 03 Jun 2016 11:32:00 +1000 In-Reply-To: <1464859370-5162-3-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1464859370-5162-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1464859370-5162-3-git-send-email-xinhui.pan@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2016-06-02 at 17:22 +0800, Pan Xinhui wrote: > Base code to enable qspinlock on powerpc. this patch add some #ifdef > here and there. Although there is no paravirt related code, we can > successfully build a qspinlock kernel after apply this patch. This is missing the IO_SYNC stuff ... It means we'll fail to do a full sync to order vs MMIOs. You need to add that back in the unlock path. > Signed-off-by: Pan Xinhui > --- >  arch/powerpc/include/asm/qspinlock.h      | 26 > ++++++++++++++++++++++++++ >  arch/powerpc/include/asm/spinlock.h       | 27 +++++++++++++++---- > -------- >  arch/powerpc/include/asm/spinlock_types.h |  4 ++++ >  arch/powerpc/lib/locks.c                  |  4 ++++ >  4 files changed, 49 insertions(+), 12 deletions(-) >  create mode 100644 arch/powerpc/include/asm/qspinlock.h > > diff --git a/arch/powerpc/include/asm/qspinlock.h > b/arch/powerpc/include/asm/qspinlock.h > new file mode 100644 > index 0000000..fc83cd2 > --- /dev/null > +++ b/arch/powerpc/include/asm/qspinlock.h > @@ -0,0 +1,26 @@ > +#ifndef _ASM_POWERPC_QSPINLOCK_H > +#define _ASM_POWERPC_QSPINLOCK_H > + > +#include > + > +#define SPIN_THRESHOLD (1 << 15) > +#define queued_spin_unlock queued_spin_unlock > + > +static inline void native_queued_spin_unlock(struct qspinlock *lock) > +{ > + u8 *locked = (u8 *)lock; > +#ifdef __BIG_ENDIAN > + locked += 3; > +#endif > + /* no load/store can be across the unlock()*/ > + smp_store_release(locked, 0); > +} > + > +static inline void queued_spin_unlock(struct qspinlock *lock) > +{ > + native_queued_spin_unlock(lock); > +} > + > +#include > + > +#endif /* _ASM_POWERPC_QSPINLOCK_H */ > diff --git a/arch/powerpc/include/asm/spinlock.h > b/arch/powerpc/include/asm/spinlock.h > index 523673d..4359ee6 100644 > --- a/arch/powerpc/include/asm/spinlock.h > +++ b/arch/powerpc/include/asm/spinlock.h > @@ -52,6 +52,20 @@ >  #define SYNC_IO >  #endif >   > +#if defined(CONFIG_PPC_SPLPAR) > +/* We only yield to the hypervisor if we are in shared processor > mode */ > +#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca- > >lppaca_ptr)) > +extern void __spin_yield(arch_spinlock_t *lock); > +extern void __rw_yield(arch_rwlock_t *lock); > +#else /* SPLPAR */ > +#define __spin_yield(x) barrier() > +#define __rw_yield(x) barrier() > +#define SHARED_PROCESSOR 0 > +#endif > + > +#ifdef CONFIG_QUEUED_SPINLOCKS > +#include > +#else >  static __always_inline int arch_spin_value_unlocked(arch_spinlock_t > lock) >  { >   return lock.slock == 0; > @@ -106,18 +120,6 @@ static inline int > arch_spin_trylock(arch_spinlock_t *lock) >   * held.  Conveniently, we have a word in the paca that holds this >   * value. >   */ > - > -#if defined(CONFIG_PPC_SPLPAR) > -/* We only yield to the hypervisor if we are in shared processor > mode */ > -#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca- > >lppaca_ptr)) > -extern void __spin_yield(arch_spinlock_t *lock); > -extern void __rw_yield(arch_rwlock_t *lock); > -#else /* SPLPAR */ > -#define __spin_yield(x) barrier() > -#define __rw_yield(x) barrier() > -#define SHARED_PROCESSOR 0 > -#endif > - >  static inline void arch_spin_lock(arch_spinlock_t *lock) >  { >   CLEAR_IO_SYNC; > @@ -169,6 +171,7 @@ extern void arch_spin_unlock_wait(arch_spinlock_t > *lock); >   do { while (arch_spin_is_locked(lock)) cpu_relax(); } while > (0) >  #endif >   > +#endif /* !CONFIG_QUEUED_SPINLOCKS */ >  /* >   * Read-write spinlocks, allowing multiple readers >   * but only one writer. > diff --git a/arch/powerpc/include/asm/spinlock_types.h > b/arch/powerpc/include/asm/spinlock_types.h > index 2351adc..bd7144e 100644 > --- a/arch/powerpc/include/asm/spinlock_types.h > +++ b/arch/powerpc/include/asm/spinlock_types.h > @@ -5,11 +5,15 @@ >  # error "please don't include this file directly" >  #endif >   > +#ifdef CONFIG_QUEUED_SPINLOCKS > +#include > +#else >  typedef struct { >   volatile unsigned int slock; >  } arch_spinlock_t; >   >  #define __ARCH_SPIN_LOCK_UNLOCKED { 0 } > +#endif >   >  typedef struct { >   volatile signed int lock; > diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c > index f7deebd..a9ebd71 100644 > --- a/arch/powerpc/lib/locks.c > +++ b/arch/powerpc/lib/locks.c > @@ -23,6 +23,7 @@ >  #include >  #include >   > +#ifndef CONFIG_QUEUED_SPINLOCKS >  void __spin_yield(arch_spinlock_t *lock) >  { >   unsigned int lock_value, holder_cpu, yield_count; > @@ -42,6 +43,7 @@ void __spin_yield(arch_spinlock_t *lock) >   get_hard_smp_processor_id(holder_cpu), yield_count); >  } >  EXPORT_SYMBOL_GPL(__spin_yield); > +#endif >   >  /* >   * Waiting for a read lock or a write lock on a rwlock... > @@ -69,6 +71,7 @@ void __rw_yield(arch_rwlock_t *rw) >  } >  #endif >   > +#ifndef CONFIG_QUEUED_SPINLOCKS >  void arch_spin_unlock_wait(arch_spinlock_t *lock) >  { >   smp_mb(); > @@ -84,3 +87,4 @@ void arch_spin_unlock_wait(arch_spinlock_t *lock) >  } >   >  EXPORT_SYMBOL(arch_spin_unlock_wait); > +#endif