diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-22 14:54:22 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-22 14:54:22 -0700 |
commit | 1bf7067c6e173dc10411704db48338ed69c05565 (patch) | |
tree | 06d731d9647c525fa598d03d7ec957ff9772ff40 /arch | |
parent | fc934d40178ad4e551a17e2733241d9f29fddd70 (diff) | |
parent | 68722101ec3a0e179408a13708dd020e04f54aab (diff) |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"The main changes are:
- 'qspinlock' support, enabled on x86: queued spinlocks - these are
now the spinlock variant used by x86 as they outperform ticket
spinlocks in every category. (Waiman Long)
- 'pvqspinlock' support on x86: paravirtualized variant of queued
spinlocks. (Waiman Long, Peter Zijlstra)
- 'qrwlock' support, enabled on x86: queued rwlocks. Similar to
queued spinlocks, they are now the variant used by x86:
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_QUEUED_RWLOCKS=y
- various lockdep fixlets
- various locking primitives cleanups, further WRITE_ONCE()
propagation"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
locking/lockdep: Remove hard coded array size dependency
locking/qrwlock: Don't contend with readers when setting _QW_WAITING
lockdep: Do not break user-visible string
locking/arch: Rename set_mb() to smp_store_mb()
locking/arch: Add WRITE_ONCE() to set_mb()
rtmutex: Warn if trylock is called from hard/softirq context
arch: Remove __ARCH_HAVE_CMPXCHG
locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG
locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS
locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS
locking/pvqspinlock: Replace xchg() by the more descriptive set_mb()
locking/pvqspinlock, x86: Enable PV qspinlock for Xen
locking/pvqspinlock, x86: Enable PV qspinlock for KVM
locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching
locking/pvqspinlock: Implement simple paravirt support for the qspinlock
locking/qspinlock: Revert to test-and-set on hypervisors
locking/qspinlock: Use a simple write to grab the lock
locking/qspinlock: Optimize for smaller NR_CPUS
locking/qspinlock: Extract out code snippets for the next patch
locking/qspinlock: Add pending bit
...
Diffstat (limited to 'arch')
40 files changed, 290 insertions, 66 deletions
diff --git a/arch/alpha/include/asm/cmpxchg.h b/arch/alpha/include/asm/cmpxchg.h index 429e8cd0d78e..e5117766529e 100644 --- a/arch/alpha/include/asm/cmpxchg.h +++ b/arch/alpha/include/asm/cmpxchg.h @@ -66,6 +66,4 @@ #undef __ASM__MB #undef ____cmpxchg -#define __HAVE_ARCH_CMPXCHG 1 - #endif /* _ALPHA_CMPXCHG_H */ diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h index d2f81e6b8c1c..6c2327e1c732 100644 --- a/arch/arm/include/asm/barrier.h +++ b/arch/arm/include/asm/barrier.h @@ -81,7 +81,7 @@ do { \ #define read_barrier_depends() do { } while(0) #define smp_read_barrier_depends() do { } while(0) -#define set_mb(var, value) do { var = value; smp_mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) #define smp_mb__before_atomic() smp_mb() #define smp_mb__after_atomic() smp_mb() diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 71f19c4dc0de..0fa47c4275cb 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -114,7 +114,7 @@ do { \ #define read_barrier_depends() do { } while(0) #define smp_read_barrier_depends() do { } while(0) -#define set_mb(var, value) do { var = value; smp_mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) #define nop() asm volatile("nop"); #define smp_mb__before_atomic() smp_mb() diff --git a/arch/avr32/include/asm/cmpxchg.h b/arch/avr32/include/asm/cmpxchg.h index 962a6aeab787..366bbeaeb405 100644 --- a/arch/avr32/include/asm/cmpxchg.h +++ b/arch/avr32/include/asm/cmpxchg.h @@ -70,8 +70,6 @@ extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels( if something tries to do an invalid cmpxchg(). */ extern void __cmpxchg_called_with_bad_pointer(void); -#define __HAVE_ARCH_CMPXCHG 1 - static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) { diff --git a/arch/hexagon/include/asm/cmpxchg.h b/arch/hexagon/include/asm/cmpxchg.h index 9e7802911a57..a6e34e2acbba 100644 --- a/arch/hexagon/include/asm/cmpxchg.h +++ b/arch/hexagon/include/asm/cmpxchg.h @@ -64,7 +64,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, * looks just like atomic_cmpxchg on our arch currently with a bunch of * variable casting. */ -#define __HAVE_ARCH_CMPXCHG 1 #define cmpxchg(ptr, old, new) \ ({ \ diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h index f6769eb2bbf9..843ba435e43b 100644 --- a/arch/ia64/include/asm/barrier.h +++ b/arch/ia64/include/asm/barrier.h @@ -77,12 +77,7 @@ do { \ ___p1; \ }) -/* - * XXX check on this ---I suspect what Linus really wants here is - * acquire vs release semantics but we can't discuss this stuff with - * Linus just yet. Grrr... - */ -#define set_mb(var, value) do { (var) = (value); mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) /* * The group barrier in front of the rsm & ssm are necessary to ensure diff --git a/arch/ia64/include/uapi/asm/cmpxchg.h b/arch/ia64/include/uapi/asm/cmpxchg.h index f35109b1d907..a0e3620f8f13 100644 --- a/arch/ia64/include/uapi/asm/cmpxchg.h +++ b/arch/ia64/include/uapi/asm/cmpxchg.h @@ -61,8 +61,6 @@ extern void ia64_xchg_called_with_bad_pointer(void); * indicated by comparing RETURN with OLD. */ -#define __HAVE_ARCH_CMPXCHG 1 - /* * This function doesn't exist, so you'll get a linker error * if something tries to do an invalid cmpxchg(). diff --git a/arch/m32r/include/asm/cmpxchg.h b/arch/m32r/include/asm/cmpxchg.h index de651db20b43..14bf9b739dd2 100644 --- a/arch/m32r/include/asm/cmpxchg.h +++ b/arch/m32r/include/asm/cmpxchg.h @@ -107,8 +107,6 @@ __xchg_local(unsigned long x, volatile void *ptr, int size) ((__typeof__(*(ptr)))__xchg_local((unsigned long)(x), (ptr), \ sizeof(*(ptr)))) -#define __HAVE_ARCH_CMPXCHG 1 - static inline unsigned long __cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new) { diff --git a/arch/m68k/include/asm/cmpxchg.h b/arch/m68k/include/asm/cmpxchg.h index bc755bc620ad..83b1df80f0ac 100644 --- a/arch/m68k/include/asm/cmpxchg.h +++ b/arch/m68k/include/asm/cmpxchg.h @@ -90,7 +90,6 @@ extern unsigned long __invalid_cmpxchg_size(volatile void *, * indicated by comparing RETURN with OLD. */ #ifdef CONFIG_RMW_INSNS -#define __HAVE_ARCH_CMPXCHG 1 static inline unsigned long __cmpxchg(volatile void *p, unsigned long old, unsigned long new, int size) diff --git a/arch/metag/include/asm/barrier.h b/arch/metag/include/asm/barrier.h index d703d8e26a65..5a696e507930 100644 --- a/arch/metag/include/asm/barrier.h +++ b/arch/metag/include/asm/barrier.h @@ -84,7 +84,7 @@ static inline void fence(void) #define read_barrier_depends() do { } while (0) #define smp_read_barrier_depends() do { } while (0) -#define set_mb(var, value) do { var = value; smp_mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) #define smp_store_release(p, v) \ do { \ diff --git a/arch/metag/include/asm/cmpxchg.h b/arch/metag/include/asm/cmpxchg.h index b1bc1be8540f..be29e3e44321 100644 --- a/arch/metag/include/asm/cmpxchg.h +++ b/arch/metag/include/asm/cmpxchg.h @@ -51,8 +51,6 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, return old; } -#define __HAVE_ARCH_CMPXCHG 1 - #define cmpxchg(ptr, o, n) \ ({ \ __typeof__(*(ptr)) _o_ = (o); \ diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h index 2b8bbbcb9be0..7ecba84656d4 100644 --- a/arch/mips/include/asm/barrier.h +++ b/arch/mips/include/asm/barrier.h @@ -112,8 +112,8 @@ #define __WEAK_LLSC_MB " \n" #endif -#define set_mb(var, value) \ - do { var = value; smp_mb(); } while (0) +#define smp_store_mb(var, value) \ + do { WRITE_ONCE(var, value); smp_mb(); } while (0) #define smp_llsc_mb() __asm__ __volatile__(__WEAK_LLSC_MB : : :"memory") diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h index 412f945f1f5e..b71ab4a5fd50 100644 --- a/arch/mips/include/asm/cmpxchg.h +++ b/arch/mips/include/asm/cmpxchg.h @@ -138,8 +138,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ }) -#define __HAVE_ARCH_CMPXCHG 1 - #define __cmpxchg_asm(ld, st, m, old, new) \ ({ \ __typeof(*(m)) __ret; \ diff --git a/arch/parisc/include/asm/cmpxchg.h b/arch/parisc/include/asm/cmpxchg.h index dbd13354ec41..0a90b965cccb 100644 --- a/arch/parisc/include/asm/cmpxchg.h +++ b/arch/parisc/include/asm/cmpxchg.h @@ -46,8 +46,6 @@ __xchg(unsigned long x, __volatile__ void *ptr, int size) #define xchg(ptr, x) \ ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) -#define __HAVE_ARCH_CMPXCHG 1 - /* bug catcher for when unsupported size is used - won't link */ extern void __cmpxchg_called_with_bad_pointer(void); diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h index 1124f59b8df4..51ccc7232042 100644 --- a/arch/powerpc/include/asm/barrier.h +++ b/arch/powerpc/include/asm/barrier.h @@ -34,7 +34,7 @@ #define rmb() __asm__ __volatile__ ("sync" : : : "memory") #define wmb() __asm__ __volatile__ ("sync" : : : "memory") -#define set_mb(var, value) do { var = value; mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) #ifdef __SUBARCH_HAS_LWSYNC # define SMPWMB LWSYNC diff --git a/arch/powerpc/include/asm/cmpxchg.h b/arch/powerpc/include/asm/cmpxchg.h index d463c68fe7f0..ad6263cffb0f 100644 --- a/arch/powerpc/include/asm/cmpxchg.h +++ b/arch/powerpc/include/asm/cmpxchg.h @@ -144,7 +144,6 @@ __xchg_local(volatile void *ptr, unsigned long x, unsigned int size) * Compare and exchange - if *p == old, set it to new, * and return the old value of *p. */ -#define __HAVE_ARCH_CMPXCHG 1 static __always_inline unsigned long __cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new) diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h index 8d724718ec21..e6f8615a11eb 100644 --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -36,7 +36,7 @@ #define smp_mb__before_atomic() smp_mb() #define smp_mb__after_atomic() smp_mb() -#define set_mb(var, value) do { var = value; mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) #define smp_store_release(p, v) \ do { \ diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h index 4eadec466b8c..411464f4c97a 100644 --- a/arch/s390/include/asm/cmpxchg.h +++ b/arch/s390/include/asm/cmpxchg.h @@ -32,8 +32,6 @@ __old; \ }) -#define __HAVE_ARCH_CMPXCHG - #define __cmpxchg_double_op(p1, p2, o1, o2, n1, n2, insn) \ ({ \ register __typeof__(*(p1)) __old1 asm("2") = (o1); \ diff --git a/arch/score/include/asm/cmpxchg.h b/arch/score/include/asm/cmpxchg.h index f384839c3ee5..cc3f6420b71c 100644 --- a/arch/score/include/asm/cmpxchg.h +++ b/arch/score/include/asm/cmpxchg.h @@ -42,8 +42,6 @@ static inline unsigned long __cmpxchg(volatile unsigned long *m, (unsigned long)(o), \ (unsigned long)(n))) -#define __HAVE_ARCH_CMPXCHG 1 - #include <asm-generic/cmpxchg-local.h> #endif /* _ASM_SCORE_CMPXCHG_H */ diff --git a/arch/sh/include/asm/barrier.h b/arch/sh/include/asm/barrier.h index 43715308b068..bf91037db4e0 100644 --- a/arch/sh/include/asm/barrier.h +++ b/arch/sh/include/asm/barrier.h @@ -32,7 +32,7 @@ #define ctrl_barrier() __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop") #endif -#define set_mb(var, value) do { (void)xchg(&var, value); } while (0) +#define smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0) #include <asm-generic/barrier.h> diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h index f6bd1406b897..85c97b188d71 100644 --- a/arch/sh/include/asm/cmpxchg.h +++ b/arch/sh/include/asm/cmpxchg.h @@ -46,8 +46,6 @@ extern void __xchg_called_with_bad_pointer(void); * if something tries to do an invalid cmpxchg(). */ extern void __cmpxchg_called_with_bad_pointer(void); -#define __HAVE_ARCH_CMPXCHG 1 - static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old, unsigned long new, int size) { diff --git a/arch/sparc/include/asm/barrier_64.h b/arch/sparc/include/asm/barrier_64.h index 76648941fea7..809941e33e12 100644 --- a/arch/sparc/include/asm/barrier_64.h +++ b/arch/sparc/include/asm/barrier_64.h @@ -40,8 +40,8 @@ do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \ #define dma_rmb() rmb() #define dma_wmb() wmb() -#define set_mb(__var, __value) \ - do { __var = __value; membar_safe("#StoreLoad"); } while(0) +#define smp_store_mb(__var, __value) \ + do { WRITE_ONCE(__var, __value); membar_safe("#StoreLoad"); } while(0) #ifdef CONFIG_SMP #define smp_mb() mb() diff --git a/arch/sparc/include/asm/cmpxchg_32.h b/arch/sparc/include/asm/cmpxchg_32.h index d38b52dca216..83ffb83c5397 100644 --- a/arch/sparc/include/asm/cmpxchg_32.h +++ b/arch/sparc/include/asm/cmpxchg_32.h @@ -34,7 +34,6 @@ static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int * * Cribbed from <asm-parisc/atomic.h> */ -#define __HAVE_ARCH_CMPXCHG 1 /* bug catcher for when unsupported size is used - won't link */ void __cmpxchg_called_with_bad_pointer(void); diff --git a/arch/sparc/include/asm/cmpxchg_64.h b/arch/sparc/include/asm/cmpxchg_64.h index 0e1ed6cfbf68..faa2f61058c2 100644 --- a/arch/sparc/include/asm/cmpxchg_64.h +++ b/arch/sparc/include/asm/cmpxchg_64.h @@ -65,8 +65,6 @@ static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, #include <asm-generic/cmpxchg-local.h> -#define __HAVE_ARCH_CMPXCHG 1 - static inline unsigned long __cmpxchg_u32(volatile int *m, int old, int new) { diff --git a/arch/tile/include/asm/atomic_64.h b/arch/tile/include/asm/atomic_64.h index 7b11c5fadd42..0496970cef82 100644 --- a/arch/tile/include/asm/atomic_64.h +++ b/arch/tile/include/asm/atomic_64.h @@ -105,9 +105,6 @@ static inline long atomic64_add_unless(atomic64_t *v, long a, long u) #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) -/* Define this to indicate that cmpxchg is an efficient operation. */ -#define __HAVE_ARCH_CMPXCHG - #endif /* !__ASSEMBLY__ */ #endif /* _ASM_TILE_ATOMIC_64_H */ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 226d5696e1d1..4e986e809861 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -127,7 +127,8 @@ config X86 select MODULES_USE_ELF_RELA if X86_64 select CLONE_BACKWARDS if X86_32 select ARCH_USE_BUILTIN_BSWAP - select ARCH_USE_QUEUE_RWLOCK + select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_USE_QUEUED_RWLOCKS select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION select OLD_SIGACTION if X86_32 select COMPAT_OLD_SIGACTION if IA32_EMULATION @@ -666,7 +667,7 @@ config PARAVIRT_DEBUG config PARAVIRT_SPINLOCKS bool "Paravirtualization layer for spinlocks" depends on PARAVIRT && SMP - select UNINLINE_SPIN_UNLOCK + select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS ---help--- Paravirtualized spinlocks allow a pvops backend to replace the spinlock implementation with something virtualization-friendly diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index 959e45b81fe2..e51a8f803f55 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -35,12 +35,12 @@ #define smp_mb() mb() #define smp_rmb() dma_rmb() #define smp_wmb() barrier() -#define set_mb(var, value) do { (void)xchg(&var, value); } while (0) +#define smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0) #else /* !SMP */ #define smp_mb() barrier() #define smp_rmb() barrier() #define smp_wmb() barrier() -#define set_mb(var, value) do { var = value; barrier(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); barrier(); } while (0) #endif /* SMP */ #define read_barrier_depends() do { } while (0) diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index 99c105d78b7e..ad19841eddfe 100644 --- a/arch/x86/include/asm/cmpxchg.h +++ b/arch/x86/include/asm/cmpxchg.h @@ -4,8 +4,6 @@ #include <linux/compiler.h> #include <asm/alternative.h> /* Provides LOCK_PREFIX */ -#define __HAVE_ARCH_CMPXCHG 1 - /* * Non-existant functions to indicate usage errors at link time * (or compile-time if the compiler implements __compiletime_error(). diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 8957810ad7d1..d143bfad45d7 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -712,6 +712,31 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx, #if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS) +#ifdef CONFIG_QUEUED_SPINLOCKS + +static __always_inline void pv_queued_spin_lock_slowpath(struct qspinlock *lock, + u32 val) +{ + PVOP_VCALL2(pv_lock_ops.queued_spin_lock_slowpath, lock, val); +} + +static __always_inline void pv_queued_spin_unlock(struct qspinlock *lock) +{ + PVOP_VCALLEE1(pv_lock_ops.queued_spin_unlock, lock); +} + +static __always_inline void pv_wait(u8 *ptr, u8 val) +{ + PVOP_VCALL2(pv_lock_ops.wait, ptr, val); +} + +static __always_inline void pv_kick(int cpu) +{ + PVOP_VCALL1(pv_lock_ops.kick, cpu); +} + +#else /* !CONFIG_QUEUED_SPINLOCKS */ + static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock, __ticket_t ticket) { @@ -724,7 +749,9 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock, PVOP_VCALL2(pv_lock_ops.unlock_kick, lock, ticket); } -#endif +#endif /* CONFIG_QUEUED_SPINLOCKS */ + +#endif /* SMP && PARAVIRT_SPINLOCKS */ #ifdef CONFIG_X86_32 #define PV_SAVE_REGS "pushl %ecx; pushl %edx;" diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index f7b0b5c112f2..8766c7c395c2 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -333,9 +333,19 @@ struct arch_spinlock; typedef u16 __ticket_t; #endif +struct qspinlock; + struct pv_lock_ops { +#ifdef CONFIG_QUEUED_SPINLOCKS + void (*queued_spin_lock_slowpath)(struct qspinlock *lock, u32 val); + struct paravirt_callee_save queued_spin_unlock; + + void (*wait)(u8 *ptr, u8 val); + void (*kick)(int cpu); +#else /* !CONFIG_QUEUED_SPINLOCKS */ struct paravirt_callee_save lock_spinning; void (*unlock_kick)(struct arch_spinlock *lock, __ticket_t ticket); +#endif /* !CONFIG_QUEUED_SPINLOCKS */ }; /* This contains all the paravirt structures: we get a convenient diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h new file mode 100644 index 000000000000..9d51fae1cba3 --- /dev/null +++ b/arch/x86/include/asm/qspinlock.h @@ -0,0 +1,57 @@ +#ifndef _ASM_X86_QSPINLOCK_H +#define _ASM_X86_QSPINLOCK_H + +#include <asm/cpufeature.h> +#include <asm-generic/qspinlock_types.h> +#include <asm/paravirt.h> + +#define queued_spin_unlock queued_spin_unlock +/** + * queued_spin_unlock - release a queued spinlock + * @lock : Pointer to queued spinlock structure + * + * A smp_store_release() on the least-significant byte. + */ +static inline void native_queued_spin_unlock(struct qspinlock *lock) +{ + smp_store_release((u8 *)lock, 0); +} + +#ifdef CONFIG_PARAVIRT_SPINLOCKS +extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val); +extern void __pv_init_lock_hash(void); +extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val); +extern void __raw_callee_save___pv_queued_spin_unlock(struct qspinlock *lock); + +static inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) +{ + pv_queued_spin_lock_slowpath(lock, val); +} + +static inline void queued_spin_unlock(struct qspinlock *lock) +{ + pv_queued_spin_unlock(lock); +} +#else +static inline void queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} +#endif + +#define virt_queued_spin_lock virt_queued_spin_lock + +static inline bool virt_queued_spin_lock(struct qspinlock *lock) +{ + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) + return false; + + while (atomic_cmpxchg(&lock->val, 0, _Q_LOCKED_VAL) != 0) + cpu_relax(); + + return true; +} + +#include <asm-generic/qspinlock.h> + +#endif /* _ASM_X86_QSPINLOCK_H */ diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h new file mode 100644 index 000000000000..b002e711ba88 --- /dev/null +++ b/arch/x86/include/asm/qspinlock_paravirt.h @@ -0,0 +1,6 @@ +#ifndef __ASM_QSPINLOCK_PARAVIRT_H +#define __ASM_QSPINLOCK_PARAVIRT_H + +PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock); + +#endif diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 64b611782ef0..be0a05913b91 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -42,6 +42,10 @@ extern struct static_key paravirt_ticketlocks_enabled; static __always_inline bool static_key_false(struct static_key *key); +#ifdef CONFIG_QUEUED_SPINLOCKS +#include <asm/qspinlock.h> +#else + #ifdef CONFIG_PARAVIRT_SPINLOCKS static inline void __ticket_enter_slowpath(arch_spinlock_t *lock) @@ -196,6 +200,7 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) cpu_relax(); } } +#endif /* CONFIG_QUEUED_SPINLOCKS */ /* * Read-write spinlocks, allowing multiple readers diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index 5f9d7572d82b..65c3e37f879a 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -23,6 +23,9 @@ typedef u32 __ticketpair_t; #define TICKET_SHIFT (sizeof(__ticket_t) * 8) +#ifdef CONFIG_QUEUED_SPINLOCKS +#include <asm-generic/qspinlock_types.h> +#else typedef struct arch_spinlock { union { __ticketpair_t head_tail; @@ -33,6 +36,7 @@ typedef struct arch_spinlock { } arch_spinlock_t; #define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } +#endif /* CONFIG_QUEUED_SPINLOCKS */ #include <asm-generic/qrwlock_types.h> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 9435620062df..1681504e44a4 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -584,6 +584,39 @@ static void kvm_kick_cpu(int cpu) kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid); } + +#ifdef CONFIG_QUEUED_SPINLOCKS + +#include <asm/qspinlock.h> + +static void kvm_wait(u8 *ptr, u8 val) +{ + unsigned long flags; + + if (in_nmi()) + return; + + local_irq_save(flags); + + if (READ_ONCE(*ptr) != val) + goto out; + + /* + * halt until it's our turn and kicked. Note that we do safe halt + * for irq enabled case to avoid hang when lock info is overwritten + * in irq spinlock slowpath and no spurious interrupt occur to save us. + */ + if (arch_irqs_disabled_flags(flags)) + halt(); + else + safe_halt(); + +out: + local_irq_restore(flags); +} + +#else /* !CONFIG_QUEUED_SPINLOCKS */ + enum kvm_contention_stat { TAKEN_SLOW, TAKEN_SLOW_PICKUP, @@ -817,6 +850,8 @@ static void kvm_unlock_kick(struct arch_spinlock *lock, __ticket_t ticket) } } +#endif /* !CONFIG_QUEUED_SPINLOCKS */ + /* * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present. |