This patch makes the necessary changes in SPARC architecture to enable queued spinlock support. Here are some of the earlier discussions about this feature. https://lwn.net/Articles/561775/ https://lwn.net/Articles/590243/ Cleaned-up the spinlock_64.h. The definitions of arch_spin_xxx are replaced by the function in <asm-generic/qspinlock.h> Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx> Reviewed-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx> Reviewed-by: Jane Chu <jane.chu@xxxxxxxxxx> Reviewed-by: Shannon Nelson <shannon.nelson@xxxxxxxxxx> Reviewed-by: Vijay Kumar <vijay.ac.kumar@xxxxxxxxxx> --- arch/sparc/Kconfig | 1 + arch/sparc/include/asm/qspinlock.h | 7 +++ arch/sparc/include/asm/spinlock_64.h | 84 +------------------------------ arch/sparc/include/asm/spinlock_types.h | 5 ++ 4 files changed, 14 insertions(+), 83 deletions(-) create mode 100644 arch/sparc/include/asm/qspinlock.h diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 9ec1d2f..d4a24ea 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -83,6 +83,7 @@ config SPARC64 select ARCH_SUPPORTS_ATOMIC_RMW select HAVE_NMI select ARCH_USE_QUEUED_RWLOCKS + select ARCH_USE_QUEUED_SPINLOCKS config ARCH_DEFCONFIG string diff --git a/arch/sparc/include/asm/qspinlock.h b/arch/sparc/include/asm/qspinlock.h new file mode 100644 index 0000000..5ae9a28 --- /dev/null +++ b/arch/sparc/include/asm/qspinlock.h @@ -0,0 +1,7 @@ +#ifndef _ASM_SPARC_QSPINLOCK_H +#define _ASM_SPARC_QSPINLOCK_H + +#include <asm-generic/qspinlock_types.h> +#include <asm-generic/qspinlock.h> + +#endif /* _ASM_SPARC_QSPINLOCK_H */ diff --git a/arch/sparc/include/asm/spinlock_64.h b/arch/sparc/include/asm/spinlock_64.h index 8901c2d..f7028f5 100644 --- a/arch/sparc/include/asm/spinlock_64.h +++ b/arch/sparc/include/asm/spinlock_64.h @@ -11,89 +11,7 @@ #include <asm/processor.h> #include <asm/barrier.h> #include <asm/qrwlock.h> - -/* To get debugging spinlocks which detect and catch - * deadlock situations, set CONFIG_DEBUG_SPINLOCK - * and rebuild your kernel. - */ - -/* Because we play games to save cycles in the non-contention case, we - * need to be extra careful about branch targets into the "spinning" - * code. They live in their own section, but the newer V9 branches - * have a shorter range than the traditional 32-bit sparc branch - * variants. The rule is that the branches that go into and out of - * the spinner sections must be pre-V9 branches. - */ - -#define arch_spin_is_locked(lp) ((lp)->lock != 0) - -static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) -{ - smp_cond_load_acquire(&lock->lock, !VAL); -} - -static inline void arch_spin_lock(arch_spinlock_t *lock) -{ - unsigned long tmp; - - __asm__ __volatile__( -"1: ldstub [%1], %0\n" -" brnz,pn %0, 2f\n" -" nop\n" -" .subsection 2\n" -"2: ldub [%1], %0\n" -" brnz,pt %0, 2b\n" -" nop\n" -" ba,a,pt %%xcc, 1b\n" -" .previous" - : "=&r" (tmp) - : "r" (lock) - : "memory"); -} - -static inline int arch_spin_trylock(arch_spinlock_t *lock) -{ - unsigned long result; - - __asm__ __volatile__( -" ldstub [%1], %0\n" - : "=r" (result) - : "r" (lock) - : "memory"); - - return (result == 0UL); -} - -static inline void arch_spin_unlock(arch_spinlock_t *lock) -{ - __asm__ __volatile__( -" stb %%g0, [%0]" - : /* No outputs */ - : "r" (lock) - : "memory"); -} - -static inline void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) -{ - unsigned long tmp1, tmp2; - - __asm__ __volatile__( -"1: ldstub [%2], %0\n" -" brnz,pn %0, 2f\n" -" nop\n" -" .subsection 2\n" -"2: rdpr %%pil, %1\n" -" wrpr %3, %%pil\n" -"3: ldub [%2], %0\n" -" brnz,pt %0, 3b\n" -" nop\n" -" ba,pt %%xcc, 1b\n" -" wrpr %1, %%pil\n" -" .previous" - : "=&r" (tmp1), "=&r" (tmp2) - : "r"(lock), "r"(flags) - : "memory"); -} +#include <asm/qspinlock.h> #define arch_read_lock_flags(p, f) arch_read_lock(p) #define arch_write_lock_flags(p, f) arch_write_lock(p) diff --git a/arch/sparc/include/asm/spinlock_types.h b/arch/sparc/include/asm/spinlock_types.h index 64fce21..bce8ef4 100644 --- a/arch/sparc/include/asm/spinlock_types.h +++ b/arch/sparc/include/asm/spinlock_types.h @@ -1,11 +1,16 @@ #ifndef __SPARC_SPINLOCK_TYPES_H #define __SPARC_SPINLOCK_TYPES_H +#ifdef CONFIG_QUEUED_SPINLOCKS +#include <asm-generic/qspinlock_types.h> +#else + typedef struct { volatile unsigned char lock; } arch_spinlock_t; #define __ARCH_SPIN_LOCK_UNLOCKED { 0 } +#endif /* CONFIG_QUEUED_SPINLOCKS */ #ifdef CONFIG_QUEUED_RWLOCKS #include <asm-generic/qrwlock_types.h> -- 1.7.1
