return !!(READ_ONCE(lock->val) & _Q_TAIL_CPU_MASK);
}
+static __always_inline u32 queued_spin_encode_locked_val(void)
+{
+ /* XXX: make this use lock value in paca like simple spinlocks? */
+ return _Q_LOCKED_VAL | (smp_processor_id() << _Q_OWNER_CPU_OFFSET);
+}
+
static __always_inline int queued_spin_trylock(struct qspinlock *lock)
{
+ u32 new = queued_spin_encode_locked_val();
u32 prev;
asm volatile(
"\t" PPC_ACQUIRE_BARRIER " \n"
"2: \n"
: "=&r" (prev)
- : "r" (&lock->val), "r" (_Q_LOCKED_VAL),
+ : "r" (&lock->val), "r" (new),
"i" (IS_ENABLED(CONFIG_PPC64))
: "cr0", "memory");
static __always_inline int __queued_spin_trylock_steal(struct qspinlock *lock)
{
+ u32 new = queued_spin_encode_locked_val();
u32 prev, tmp;
/* Trylock may get ahead of queued nodes if it finds unlocked */
"\t" PPC_ACQUIRE_BARRIER " \n"
"2: \n"
: "=&r" (prev), "=&r" (tmp)
- : "r" (&lock->val), "r" (_Q_LOCKED_VAL), "r" (_Q_TAIL_CPU_MASK),
+ : "r" (&lock->val), "r" (new), "r" (_Q_TAIL_CPU_MASK),
"i" (IS_ENABLED(CONFIG_PPC64))
: "cr0", "memory");
* Bitfields in the lock word:
*
* 0: locked bit
- * 1-15: unused bits
+ * 1-14: lock holder cpu
+ * 15: unused bit
* 16: must queue bit
* 17-31: tail cpu (+1)
*/
#define _Q_LOCKED_BITS 1
#define _Q_LOCKED_VAL (1U << _Q_LOCKED_OFFSET)
+/* 0x00007ffe */
+#define _Q_OWNER_CPU_OFFSET 1
+#define _Q_OWNER_CPU_BITS 14
+#define _Q_OWNER_CPU_MASK _Q_SET_MASK(OWNER_CPU)
+
+#if CONFIG_NR_CPUS > (1U << _Q_OWNER_CPU_BITS)
+#error "qspinlock does not support such large CONFIG_NR_CPUS"
+#endif
+
/* 0x00010000 */
#define _Q_MUST_Q_OFFSET 16
#define _Q_MUST_Q_BITS 1