#include "syscall.h"
#include "libc.h"
+static void dummy1(int x) { }
+static void dummy0(void) { }
+weak_alias(dummy1, __vm_lock);
+weak_alias(dummy0, __vm_unlock);
+
void *__mmap(void *start, size_t len, int prot, int flags, int fd, off_t off)
{
+ void *ret;
if (sizeof(off_t) > sizeof(long))
if (((long)off & 0xfff) | ((long)((unsigned long long)off>>(12 + 8*(sizeof(off_t)-sizeof(long))))))
start = (void *)-1;
+ if (flags & MAP_FIXED) __vm_lock(-1);
#ifdef SYS_mmap2
- return (void *)syscall(SYS_mmap2, start, len, prot, flags, fd, off>>12);
+ ret = (void *)syscall(SYS_mmap2, start, len, prot, flags, fd, off>>12);
#else
- return (void *)syscall(SYS_mmap, start, len, prot, flags, fd, off);
+ ret = (void *)syscall(SYS_mmap, start, len, prot, flags, fd, off);
#endif
+ if (flags & MAP_FIXED) __vm_unlock();
+ return ret;
}
weak_alias(__mmap, mmap);
#include "pthread_impl.h"
+static int vmlock[2];
+
+void __vm_lock(int inc)
+{
+ for (;;) {
+ int v = vmlock[0];
+ if (inc*v < 0) __wait(vmlock, vmlock+1, v, 1);
+ else if (a_cas(vmlock, v, v+inc)==v) break;
+ }
+}
+
+void __vm_unlock(void)
+{
+ if (vmlock[0]>0) a_dec(vmlock);
+ else a_inc(vmlock);
+ if (vmlock[1]) __wake(vmlock, 1, 1);
+}
+
+static int pshared_barrier_wait(pthread_barrier_t *b)
+{
+ int limit = (b->_b_limit & INT_MAX) + 1;
+ int seq;
+ int ret = 0;
+
+ if (!limit) return PTHREAD_BARRIER_SERIAL_THREAD;
+
+ while (a_swap(&b->_b_lock, 1))
+ __wait(&b->_b_lock, &b->_b_waiters, 1, 0);
+
+ seq = b->_b_seq;
+
+ if (++b->_b_count == limit) {
+ ret = PTHREAD_BARRIER_SERIAL_THREAD;
+ b->_b_seq++;
+ __wake(&b->_b_seq, -1, 0);
+ } else {
+ a_store(&b->_b_lock, 0);
+ if (b->_b_waiters) __wake(&b->_b_lock, 1, 0);
+ __wait(&b->_b_seq, 0, seq, 0);
+ }
+
+ __vm_lock(+1);
+
+ if (a_fetch_add(&b->_b_count, -1)==1) {
+ b->_b_seq++;
+ __wake(&b->_b_seq, -1, 0);
+ a_store(&b->_b_lock, 0);
+ if (b->_b_waiters) __wake(&b->_b_lock, 1, 0);
+ } else {
+ __wait(&b->_b_seq, 0, seq+1, 0);
+ }
+
+ __vm_unlock();
+
+ return 0;
+}
+
struct instance
{
int count;
/* Trivial case: count was set at 1 */
if (!limit) return PTHREAD_BARRIER_SERIAL_THREAD;
+ /* Process-shared barriers require a separate, inefficient wait */
+ if (limit < 0) return pshared_barrier_wait(b);
+
/* Otherwise we need a lock on the barrier object */
while (a_swap(&b->_b_lock, 1))
- __wait(&b->_b_lock, &b->_b_waiters, 1, 0);
+ __wait(&b->_b_lock, &b->_b_waiters, 1, 1);
inst = b->_b_inst;
/* First thread to enter the barrier becomes the "instance owner" */
int spins = 10000;
b->_b_inst = inst = &new_inst;
a_store(&b->_b_lock, 0);
- if (b->_b_waiters) __wake(&b->_b_lock, 1, 0);
+ if (b->_b_waiters) __wake(&b->_b_lock, 1, 1);
while (spins-- && !inst->finished)
a_spin();
a_inc(&inst->finished);
if (++inst->count == limit) {
b->_b_inst = 0;
a_store(&b->_b_lock, 0);
- if (b->_b_waiters) __wake(&b->_b_lock, 1, 0);
+ if (b->_b_waiters) __wake(&b->_b_lock, 1, 1);
a_store(&inst->last, 1);
if (inst->waiters)
- __wake(&inst->last, -1, 0);
+ __wake(&inst->last, -1, 1);
} else {
a_store(&b->_b_lock, 0);
- if (b->_b_waiters) __wake(&b->_b_lock, 1, 0);
- __wait(&inst->last, &inst->waiters, 0, 0);
+ if (b->_b_waiters) __wake(&b->_b_lock, 1, 1);
+ __wait(&inst->last, &inst->waiters, 0, 1);
}
/* Last thread to exit the barrier wakes the instance owner */
if (a_fetch_add(&inst->count,-1)==1 && a_fetch_add(&inst->finished,1))
- __wake(&inst->finished, 1, 0);
+ __wake(&inst->finished, 1, 1);
return 0;
}