Differential D31254 Diff 92935 sys/compat/linux/linux_futex.c

Changeset View

Standalone View

sys/compat/linux/linux_futex.c

Show First 20 Lines • Show All 101 Lines • ▼ Show 20 Lines
LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");		LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");		LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");

#define FUTEX_SHARED 0x8 /* shared futex */		#define FUTEX_SHARED 0x8 /* shared futex */

#define GET_SHARED(a) (a->flags & FUTEX_SHARED) ? AUTO_SHARE : THREAD_SHARE		#define GET_SHARED(a) (a->flags & FUTEX_SHARED) ? AUTO_SHARE : THREAD_SHARE

static int futex_atomic_op(struct thread , int, uint32_t );		static int futex_atomic_op(struct thread , int, uint32_t );
static int handle_futex_death(struct linux_emuldata , uint32_t ,		static int handle_futex_death(struct thread td, struct linux_emuldata ,
unsigned int);		uint32_t *, unsigned int);
static int fetch_robust_entry(struct linux_robust_list **,		static int fetch_robust_entry(struct linux_robust_list **,
struct linux_robust_list *, unsigned int );		struct linux_robust_list *, unsigned int );

struct linux_futex_args {		struct linux_futex_args {
uint32_t *uaddr;		uint32_t *uaddr;
int32_t op;		int32_t op;
uint32_t flags;		uint32_t flags;
bool clockrt;		bool clockrt;
▲ Show 20 Lines • Show All 857 Lines • ▼ Show 20 Lines	if (error) {
LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,		LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
error);		error);
}		}

return (error);		return (error);
}		}

static int		static int
handle_futex_death(struct linux_emuldata em, uint32_t uaddr,		handle_futex_death(struct thread td, struct linux_emuldata em, uint32_t *uaddr,
unsigned int pi)		unsigned int pi)
{		{
uint32_t uval, nval, mval;		uint32_t uval, nval, mval;
int error;		int error;

retry:		retry:
error = fueword32(uaddr, &uval);		error = fueword32(uaddr, &uval);
if (error != 0)		if (error != 0)
return (EFAULT);		return (EFAULT);
if ((uval & FUTEX_TID_MASK) == em->em_tid) {		if ((uval & FUTEX_TID_MASK) == em->em_tid) {
mval = (uval & FUTEX_WAITERS) \| FUTEX_OWNER_DIED;		mval = (uval & FUTEX_WAITERS) \| FUTEX_OWNER_DIED;
nval = casuword32(uaddr, uval, mval);		error = casueword32(uaddr, uval, &nval, mval);
		if (error == -1)
if (nval == -1)
return (EFAULT);		return (EFAULT);
		if (error == 1) {
if (nval != uval)		error = thread_check_susp(td, false);
		if (error != 0)
		kibUnsubmitted Not Done Inline Actions error != 0 kib: error != 0
		return (error);
goto retry;		goto retry;
		}
		kibUnsubmitted Not Done Inline Actions This is fine as the step, but please look at 30b3018d48e4441083b483 kib: This is fine as the step, but please look at 30b3018d48e4441083b483
		dchaginAuthorUnsubmitted Not Done Inline Actions sure, did I understand correctly that on ll/sc architectures casueword can fails as there are two operations, and exceptional events between this operations can lead the second operation (store-conditional) to spuriously fail. So before repeating we need a check for stops etc...? If so, I need to revise all of new futex code )) dchagin: sure, did I understand correctly that on ll/sc architectures casueword can fails as there are…
		kibUnsubmitted Not Done Inline Actions Right. Generally casueword is allowed to spuriously fail on all arches, same as cmpset/fcmpset. kib: Right. Generally casueword is allowed to spuriously fail on all arches, same as cmpset/fcmpset.

if (!pi && (uval & FUTEX_WAITERS)) {		if (!pi && (uval & FUTEX_WAITERS)) {
error = futex_wake(curthread, uaddr, 1, true);		error = futex_wake(td, uaddr, 1, true);
if (error != 0)		if (error != 0)
return (error);		return (error);
} else if (pi && (uval & FUTEX_WAITERS)) {		} else if (pi && (uval & FUTEX_WAITERS)) {
error = futex_wake_pi(curthread, uaddr, true);		error = futex_wake_pi(td, uaddr, true);
if (error != 0)		if (error != 0)
return (error);		return (error);
}		}
}		}

return (0);		return (0);
}		}

▲ Show 20 Lines • Show All 43 Lines • ▼ Show 20 Lines	release_futexes(struct thread td, struct linux_emuldata em)

if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip))		if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip))
return;		return;

while (entry != &head->list) {		while (entry != &head->list) {
rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);		rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);

if (entry != pending)		if (entry != pending)
if (handle_futex_death(em,		if (handle_futex_death(td, em,
(uint32_t *)((caddr_t)entry + futex_offset), pi)) {		(uint32_t *)((caddr_t)entry + futex_offset), pi)) {
return;		return;
}		}
if (rc)		if (rc)
return;		return;

entry = next_entry;		entry = next_entry;
pi = next_pi;		pi = next_pi;

if (!--limit)		if (!--limit)
break;		break;

sched_relinquish(curthread);		sched_relinquish(curthread);
}		}

if (pending)		if (pending)
handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);		handle_futex_death(td, em,
		(uint32_t *)((caddr_t)pending + futex_offset), pip);
}		}