--- /dev/null
+/* spinlock.h: 64-bit Sparc spinlock support.
+ *
+ * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#ifndef __SPARC64_SPINLOCK_H
+#define __SPARC64_SPINLOCK_H
+
+#ifndef __ASSEMBLY__
+
+/* 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)
+
+#define arch_spin_unlock_wait(lp) \
+ do { rmb(); \
+ } while((lp)->lock)
+
+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");
+}
+
+/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
+
+static void inline arch_read_lock(arch_rwlock_t *lock)
+{
+ unsigned long tmp1, tmp2;
+
+ __asm__ __volatile__ (
+"1: ldsw [%2], %0\n"
+" brlz,pn %0, 2f\n"
+"4: add %0, 1, %1\n"
+" cas [%2], %0, %1\n"
+" cmp %0, %1\n"
+" bne,pn %%icc, 1b\n"
+" nop\n"
+" .subsection 2\n"
+"2: ldsw [%2], %0\n"
+" brlz,pt %0, 2b\n"
+" nop\n"
+" ba,a,pt %%xcc, 4b\n"
+" .previous"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock)
+ : "memory");
+}
+
+static int inline arch_read_trylock(arch_rwlock_t *lock)
+{
+ int tmp1, tmp2;
+
+ __asm__ __volatile__ (
+"1: ldsw [%2], %0\n"
+" brlz,a,pn %0, 2f\n"
+" mov 0, %0\n"
+" add %0, 1, %1\n"
+" cas [%2], %0, %1\n"
+" cmp %0, %1\n"
+" bne,pn %%icc, 1b\n"
+" mov 1, %0\n"
+"2:"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock)
+ : "memory");
+
+ return tmp1;
+}
+
+static void inline arch_read_unlock(arch_rwlock_t *lock)
+{
+ unsigned long tmp1, tmp2;
+
+ __asm__ __volatile__(
+"1: lduw [%2], %0\n"
+" sub %0, 1, %1\n"
+" cas [%2], %0, %1\n"
+" cmp %0, %1\n"
+" bne,pn %%xcc, 1b\n"
+" nop"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock)
+ : "memory");
+}
+
+static void inline arch_write_lock(arch_rwlock_t *lock)
+{
+ unsigned long mask, tmp1, tmp2;
+
+ mask = 0x80000000UL;
+
+ __asm__ __volatile__(
+"1: lduw [%2], %0\n"
+" brnz,pn %0, 2f\n"
+"4: or %0, %3, %1\n"
+" cas [%2], %0, %1\n"
+" cmp %0, %1\n"
+" bne,pn %%icc, 1b\n"
+" nop\n"
+" .subsection 2\n"
+"2: lduw [%2], %0\n"
+" brnz,pt %0, 2b\n"
+" nop\n"
+" ba,a,pt %%xcc, 4b\n"
+" .previous"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock), "r" (mask)
+ : "memory");
+}
+
+static void inline arch_write_unlock(arch_rwlock_t *lock)
+{
+ __asm__ __volatile__(
+" stw %%g0, [%0]"
+ : /* no outputs */
+ : "r" (lock)
+ : "memory");
+}
+
+static int inline arch_write_trylock(arch_rwlock_t *lock)
+{
+ unsigned long mask, tmp1, tmp2, result;
+
+ mask = 0x80000000UL;
+
+ __asm__ __volatile__(
+" mov 0, %2\n"
+"1: lduw [%3], %0\n"
+" brnz,pn %0, 2f\n"
+" or %0, %4, %1\n"
+" cas [%3], %0, %1\n"
+" cmp %0, %1\n"
+" bne,pn %%icc, 1b\n"
+" nop\n"
+" mov 1, %2\n"
+"2:"
+ : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
+ : "r" (lock), "r" (mask)
+ : "memory");
+
+ return result;
+}
+
+#define arch_read_lock_flags(p, f) arch_read_lock(p)
+#define arch_write_lock_flags(p, f) arch_write_lock(p)
+
+#define arch_read_can_lock(rw) (!((rw)->lock & 0x80000000UL))
+#define arch_write_can_lock(rw) (!(rw)->lock)
+
+#define arch_spin_relax(lock) cpu_relax()
+#define arch_read_relax(lock) cpu_relax()
+#define arch_write_relax(lock) cpu_relax()
+
+#endif /* !(__ASSEMBLY__) */
+
+#endif /* !(__SPARC64_SPINLOCK_H) */
Code Review / kvmfornfv.git / blobdiff