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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-sparc64/spinlock.h
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-sparc64/spinlock.h')
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diff --git a/include/asm-sparc64/spinlock.h b/include/asm-sparc64/spinlock.h
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+/* 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
+
+#include <linux/config.h>
+#include <linux/threads.h> /* For NR_CPUS */
+
+#ifndef __ASSEMBLY__
+
+/* To get debugging spinlocks which detect and catch
+ * deadlock situations, set CONFIG_DEBUG_SPINLOCK
+ * and rebuild your kernel.
+ */
+
+/* All of these locking primitives are expected to work properly
+ * even in an RMO memory model, which currently is what the kernel
+ * runs in.
+ *
+ * There is another issue. 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.
+ */
+
+#ifndef CONFIG_DEBUG_SPINLOCK
+
+typedef unsigned char spinlock_t;
+#define SPIN_LOCK_UNLOCKED 0
+
+#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0)
+#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
+
+#define spin_unlock_wait(lock) \
+do { membar("#LoadLoad"); \
+} while(*((volatile unsigned char *)lock))
+
+static inline void _raw_spin_lock(spinlock_t *lock)
+{
+ unsigned long tmp;
+
+ __asm__ __volatile__(
+"1: ldstub [%1], %0\n"
+" brnz,pn %0, 2f\n"
+" membar #StoreLoad | #StoreStore\n"
+" .subsection 2\n"
+"2: ldub [%1], %0\n"
+" brnz,pt %0, 2b\n"
+" membar #LoadLoad\n"
+" ba,a,pt %%xcc, 1b\n"
+" .previous"
+ : "=&r" (tmp)
+ : "r" (lock)
+ : "memory");
+}
+
+static inline int _raw_spin_trylock(spinlock_t *lock)
+{
+ unsigned long result;
+
+ __asm__ __volatile__(
+" ldstub [%1], %0\n"
+" membar #StoreLoad | #StoreStore"
+ : "=r" (result)
+ : "r" (lock)
+ : "memory");
+
+ return (result == 0UL);
+}
+
+static inline void _raw_spin_unlock(spinlock_t *lock)
+{
+ __asm__ __volatile__(
+" membar #StoreStore | #LoadStore\n"
+" stb %%g0, [%0]"
+ : /* No outputs */
+ : "r" (lock)
+ : "memory");
+}
+
+static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
+{
+ unsigned long tmp1, tmp2;
+
+ __asm__ __volatile__(
+"1: ldstub [%2], %0\n"
+" brnz,pn %0, 2f\n"
+" membar #StoreLoad | #StoreStore\n"
+" .subsection 2\n"
+"2: rdpr %%pil, %1\n"
+" wrpr %3, %%pil\n"
+"3: ldub [%2], %0\n"
+" brnz,pt %0, 3b\n"
+" membar #LoadLoad\n"
+" ba,pt %%xcc, 1b\n"
+" wrpr %1, %%pil\n"
+" .previous"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r"(lock), "r"(flags)
+ : "memory");
+}
+
+#else /* !(CONFIG_DEBUG_SPINLOCK) */
+
+typedef struct {
+ unsigned char lock;
+ unsigned int owner_pc, owner_cpu;
+} spinlock_t;
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
+#define spin_lock_init(__lock) \
+do { (__lock)->lock = 0; \
+ (__lock)->owner_pc = 0; \
+ (__lock)->owner_cpu = 0xff; \
+} while(0)
+#define spin_is_locked(__lock) (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
+#define spin_unlock_wait(__lock) \
+do { \
+ membar("#LoadLoad"); \
+} while(*((volatile unsigned char *)(&((__lock)->lock))))
+
+extern void _do_spin_lock (spinlock_t *lock, char *str);
+extern void _do_spin_unlock (spinlock_t *lock);
+extern int _do_spin_trylock (spinlock_t *lock);
+
+#define _raw_spin_trylock(lp) _do_spin_trylock(lp)
+#define _raw_spin_lock(lock) _do_spin_lock(lock, "spin_lock")
+#define _raw_spin_unlock(lock) _do_spin_unlock(lock)
+#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+
+#endif /* CONFIG_DEBUG_SPINLOCK */
+
+/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
+
+#ifndef CONFIG_DEBUG_SPINLOCK
+
+typedef unsigned int rwlock_t;
+#define RW_LOCK_UNLOCKED 0
+#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
+
+static void inline __read_lock(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"
+" membar #StoreLoad | #StoreStore\n"
+" .subsection 2\n"
+"2: ldsw [%2], %0\n"
+" brlz,pt %0, 2b\n"
+" membar #LoadLoad\n"
+" ba,a,pt %%xcc, 4b\n"
+" .previous"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock)
+ : "memory");
+}
+
+static void inline __read_unlock(rwlock_t *lock)
+{
+ unsigned long tmp1, tmp2;
+
+ __asm__ __volatile__(
+" membar #StoreLoad | #LoadLoad\n"
+"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 __write_lock(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"
+" membar #StoreLoad | #StoreStore\n"
+" .subsection 2\n"
+"2: lduw [%2], %0\n"
+" brnz,pt %0, 2b\n"
+" membar #LoadLoad\n"
+" ba,a,pt %%xcc, 4b\n"
+" .previous"
+ : "=&r" (tmp1), "=&r" (tmp2)
+ : "r" (lock), "r" (mask)
+ : "memory");
+}
+
+static void inline __write_unlock(rwlock_t *lock)
+{
+ __asm__ __volatile__(
+" membar #LoadStore | #StoreStore\n"
+" stw %%g0, [%0]"
+ : /* no outputs */
+ : "r" (lock)
+ : "memory");
+}
+
+static int inline __write_trylock(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"
+" membar #StoreLoad | #StoreStore\n"
+" mov 1, %2\n"
+"2:"
+ : "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
+ : "r" (lock), "r" (mask)
+ : "memory");
+
+ return result;
+}
+
+#define _raw_read_lock(p) __read_lock(p)
+#define _raw_read_unlock(p) __read_unlock(p)
+#define _raw_write_lock(p) __write_lock(p)
+#define _raw_write_unlock(p) __write_unlock(p)
+#define _raw_write_trylock(p) __write_trylock(p)
+
+#else /* !(CONFIG_DEBUG_SPINLOCK) */
+
+typedef struct {
+ unsigned long lock;
+ unsigned int writer_pc, writer_cpu;
+ unsigned int reader_pc[NR_CPUS];
+} rwlock_t;
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, 0xff, { } }
+#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
+
+extern void _do_read_lock(rwlock_t *rw, char *str);
+extern void _do_read_unlock(rwlock_t *rw, char *str);
+extern void _do_write_lock(rwlock_t *rw, char *str);
+extern void _do_write_unlock(rwlock_t *rw);
+extern int _do_write_trylock(rwlock_t *rw, char *str);
+
+#define _raw_read_lock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_read_lock(lock, "read_lock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_read_unlock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_read_unlock(lock, "read_unlock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_write_lock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_write_lock(lock, "write_lock"); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_write_unlock(lock) \
+do { unsigned long flags; \
+ local_irq_save(flags); \
+ _do_write_unlock(lock); \
+ local_irq_restore(flags); \
+} while(0)
+
+#define _raw_write_trylock(lock) \
+({ unsigned long flags; \
+ int val; \
+ local_irq_save(flags); \
+ val = _do_write_trylock(lock, "write_trylock"); \
+ local_irq_restore(flags); \
+ val; \
+})
+
+#endif /* CONFIG_DEBUG_SPINLOCK */
+
+#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
+
+#endif /* !(__ASSEMBLY__) */
+
+#endif /* !(__SPARC64_SPINLOCK_H) */