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    Subjectalpha spinlock.h update
    On Tue, Mar 22, 2005 at 01:01:45PM -0800, Andrew Morton wrote:
    > I had the impression Richard planned on something more sophisticated
    > than this??

    Indeed. I suppose I can pass it along to avoid repeated "it doesn't build"
    messages, but an smp kernel doesn't run. *All* processes spawned by init(1)
    die with SIGILL very very shortly. I can only guess that there's been some
    change to flushing (icache or tlb) that went wrong.



    r~



    ===== include/asm-alpha/spinlock.h 1.14 vs edited =====
    --- 1.14/include/asm-alpha/spinlock.h 2005-01-20 08:21:23 -08:00
    +++ edited/include/asm-alpha/spinlock.h 2005-03-20 13:53:46 -08:00
    @@ -15,7 +15,7 @@
    */

    typedef struct {
    - volatile unsigned int lock /*__attribute__((aligned(32))) */;
    + volatile unsigned int lock;
    #ifdef CONFIG_DEBUG_SPINLOCK
    int on_cpu;
    int line_no;
    @@ -23,40 +23,26 @@
    struct task_struct * task;
    const char *base_file;
    #endif
    -#ifdef CONFIG_PREEMPT
    - unsigned int break_lock;
    -#endif
    } spinlock_t;

    #ifdef CONFIG_DEBUG_SPINLOCK
    -#define SPIN_LOCK_UNLOCKED (spinlock_t) {0, -1, 0, NULL, NULL, NULL}
    -#define spin_lock_init(x) \
    - ((x)->lock = 0, (x)->on_cpu = -1, (x)->previous = NULL, (x)->task = NULL)
    +#define SPIN_LOCK_UNLOCKED (spinlock_t){ 0, -1, 0, NULL, NULL, NULL }
    #else
    -#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
    -#define spin_lock_init(x) ((x)->lock = 0)
    +#define SPIN_LOCK_UNLOCKED (spinlock_t){ 0 }
    #endif

    +#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
    #define spin_is_locked(x) ((x)->lock != 0)
    -#define spin_unlock_wait(x) ({ do { barrier(); } while ((x)->lock); })
    -#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
    +#define spin_unlock_wait(x) do { barrier(); } while ((x)->lock)

    #ifdef CONFIG_DEBUG_SPINLOCK
    extern void _raw_spin_unlock(spinlock_t * lock);
    extern void debug_spin_lock(spinlock_t * lock, const char *, int);
    extern int debug_spin_trylock(spinlock_t * lock, const char *, int);
    -
    -#define _raw_spin_lock(LOCK) debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
    -#define _raw_spin_trylock(LOCK) debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
    -
    -#define spin_lock_own(LOCK, LOCATION) \
    -do { \
    - if (!((LOCK)->lock && (LOCK)->on_cpu == smp_processor_id())) \
    - printk("%s: called on %d from %p but lock %s on %d\n", \
    - LOCATION, smp_processor_id(), \
    - __builtin_return_address(0), \
    - (LOCK)->lock ? "taken" : "freed", (LOCK)->on_cpu); \
    -} while (0)
    +#define _raw_spin_lock(LOCK) \
    + debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
    +#define _raw_spin_trylock(LOCK) \
    + debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
    #else
    static inline void _raw_spin_unlock(spinlock_t * lock)
    {
    @@ -68,19 +54,16 @@
    {
    long tmp;

    - /* Use sub-sections to put the actual loop at the end
    - of this object file's text section so as to perfect
    - branch prediction. */
    __asm__ __volatile__(
    "1: ldl_l %0,%1\n"
    - " blbs %0,2f\n"
    - " or %0,1,%0\n"
    + " bne %0,2f\n"
    + " lda %0,1\n"
    " stl_c %0,%1\n"
    " beq %0,2f\n"
    " mb\n"
    ".subsection 2\n"
    "2: ldl %0,%1\n"
    - " blbs %0,2b\n"
    + " bne %0,2b\n"
    " br 1b\n"
    ".previous"
    : "=&r" (tmp), "=m" (lock->lock)
    @@ -91,22 +74,29 @@
    {
    return !test_and_set_bit(0, &lock->lock);
    }
    -
    -#define spin_lock_own(LOCK, LOCATION) ((void)0)
    #endif /* CONFIG_DEBUG_SPINLOCK */

    +#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
    +
    /***********************************************************/

    typedef struct {
    - volatile unsigned int write_lock:1, read_counter:31;
    -#ifdef CONFIG_PREEMPT
    - unsigned int break_lock;
    -#endif
    -} /*__attribute__((aligned(32)))*/ rwlock_t;
    + volatile unsigned int lock;
    +} rwlock_t;
    +
    +#define RW_LOCK_UNLOCKED (rwlock_t){ 0 }

    -#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
    +#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)

    -#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
    +static inline int read_can_lock(rwlock_t *lock)
    +{
    + return (lock->lock & 1) == 0;
    +}
    +
    +static inline int write_can_lock(rwlock_t *lock)
    +{
    + return lock->lock == 0;
    +}

    #ifdef CONFIG_DEBUG_RWLOCK
    extern void _raw_write_lock(rwlock_t * lock);
    @@ -119,7 +109,7 @@
    __asm__ __volatile__(
    "1: ldl_l %1,%0\n"
    " bne %1,6f\n"
    - " or $31,1,%1\n"
    + " lda %1,1\n"
    " stl_c %1,%0\n"
    " beq %1,6f\n"
    " mb\n"
    @@ -142,7 +132,7 @@
    " subl %1,2,%1\n"
    " stl_c %1,%0\n"
    " beq %1,6f\n"
    - "4: mb\n"
    + " mb\n"
    ".subsection 2\n"
    "6: ldl %1,%0\n"
    " blbs %1,6b\n"
    @@ -153,6 +143,28 @@
    }
    #endif /* CONFIG_DEBUG_RWLOCK */

    +static inline int _raw_read_trylock(rwlock_t * lock)
    +{
    + long regx;
    + int success;
    +
    + __asm__ __volatile__(
    + "1: ldl_l %1,%0\n"
    + " lda %2,0\n"
    + " blbs %1,2f\n"
    + " subl %1,2,%2\n"
    + " stl_c %2,%0\n"
    + " beq %2,6f\n"
    + "2: mb\n"
    + ".subsection 2\n"
    + "6: br 1b\n"
    + ".previous"
    + : "=m" (*lock), "=&r" (regx), "=&r" (success)
    + : "m" (*lock) : "memory");
    +
    + return success;
    +}
    +
    static inline int _raw_write_trylock(rwlock_t * lock)
    {
    long regx;
    @@ -162,10 +174,9 @@
    "1: ldl_l %1,%0\n"
    " lda %2,0\n"
    " bne %1,2f\n"
    - " or $31,1,%1\n"
    - " stl_c %1,%0\n"
    - " beq %1,6f\n"
    " lda %2,1\n"
    + " stl_c %2,%0\n"
    + " beq %2,6f\n"
    "2: mb\n"
    ".subsection 2\n"
    "6: br 1b\n"
    @@ -179,7 +190,7 @@
    static inline void _raw_write_unlock(rwlock_t * lock)
    {
    mb();
    - *(volatile int *)lock = 0;
    + lock->lock = 0;
    }

    static inline void _raw_read_unlock(rwlock_t * lock)
    -
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