Module: xenomai-3
Branch: wip/prioceil
Commit: 8df8a403a09c8cf9ddc07c8e8fb589e43715bde6
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=8df8a403a09c8cf9ddc07c8e8fb589e43715bde6
Author: Philippe Gerum <r...@xenomai.org>
Date: Tue Feb 16 10:13:03 2016 +0100
lib/cobalt/mutex: add support for priority ceiling protocol
---
configure.ac | 2 +
include/boilerplate/libc.h | 19 +++
include/cobalt/pthread.h | 7 ++
lib/cobalt/cobalt.wrappers | 2 +
lib/cobalt/init.c | 1 +
lib/cobalt/internal.h | 8 ++
lib/cobalt/mutex.c | 301 +++++++++++++++++++++++++++++++++++---------
lib/cobalt/sched.c | 33 ++++-
lib/cobalt/thread.c | 7 +-
9 files changed, 311 insertions(+), 69 deletions(-)
diff --git a/configure.ac b/configure.ac
index 8bbeeef..578327e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -504,6 +504,8 @@ save_LIBS="$LIBS"
LIBS="$LIBS -lrt -lpthread"
AC_CHECK_FUNCS([pthread_mutexattr_setprotocol \
pthread_mutexattr_getprotocol \
+ pthread_mutexattr_getprioceiling \
+ pthread_mutexattr_setprioceiling \
pthread_mutexattr_setrobust_np \
pthread_condattr_getclock \
pthread_condattr_setclock \
diff --git a/include/boilerplate/libc.h b/include/boilerplate/libc.h
index 0e51b86..3a5af8c 100644
--- a/include/boilerplate/libc.h
+++ b/include/boilerplate/libc.h
@@ -108,6 +108,25 @@ int pthread_mutexattr_getprotocol(const
pthread_mutexattr_t *
}
#endif /* !HAVE_PTHREAD_MUTEXATTR_GETPROTOCOL */
+#ifndef HAVE_PTHREAD_MUTEXATTR_SETPRIOCEILING
+static inline
+int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
+ int prioceiling)
+{
+ return ENOSYS;
+}
+#endif /* !HAVE_PTHREAD_MUTEXATTR_SETPRIOCEILING */
+
+#ifndef HAVE_PTHREAD_MUTEXATTR_GETPRIOCEILING
+static inline
+int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *
+ __restrict attr,
+ int *__restrict prioceiling)
+{
+ return ENOSYS;
+}
+#endif /* !HAVE_PTHREAD_MUTEXATTR_GETPRIOCEILING */
+
#ifndef HAVE_PTHREAD_ATTR_SETAFFINITY_NP
#include <sched.h>
static inline
diff --git a/include/cobalt/pthread.h b/include/cobalt/pthread.h
index 386c337..f1b1c8a 100644
--- a/include/cobalt/pthread.h
+++ b/include/cobalt/pthread.h
@@ -67,6 +67,13 @@ COBALT_DECL(int, pthread_mutex_trylock(pthread_mutex_t
*mutex));
COBALT_DECL(int, pthread_mutex_unlock(pthread_mutex_t *mutex));
+COBALT_DECL(int, pthread_mutex_setprioceiling(pthread_mutex_t *__restrict
mutex,
+ int prioceiling,
+ int *__restrict old_ceiling));
+
+COBALT_DECL(int, pthread_mutex_getprioceiling(pthread_mutex_t *__restrict
mutex,
+ int *__restrict old_ceiling));
+
COBALT_DECL(int, pthread_cond_init (pthread_cond_t *cond,
const pthread_condattr_t *attr));
diff --git a/lib/cobalt/cobalt.wrappers b/lib/cobalt/cobalt.wrappers
index 9480f34..75f29d6 100644
--- a/lib/cobalt/cobalt.wrappers
+++ b/lib/cobalt/cobalt.wrappers
@@ -32,6 +32,8 @@
--wrap pthread_mutex_trylock
--wrap pthread_mutex_timedlock
--wrap pthread_mutex_unlock
+--wrap pthread_mutex_setprioceiling
+--wrap pthread_mutex_getprioceiling
--wrap pthread_cond_init
--wrap pthread_cond_destroy
--wrap pthread_cond_wait
diff --git a/lib/cobalt/init.c b/lib/cobalt/init.c
index f260744..69d4763 100644
--- a/lib/cobalt/init.c
+++ b/lib/cobalt/init.c
@@ -177,6 +177,7 @@ static void __cobalt_init(void)
sizeof(struct cobalt_sem_shadow));
cobalt_mutex_init();
+ cobalt_sched_init();
cobalt_thread_init();
cobalt_print_init();
}
diff --git a/lib/cobalt/internal.h b/lib/cobalt/internal.h
index 69ec7d1..cdb2eee 100644
--- a/lib/cobalt/internal.h
+++ b/lib/cobalt/internal.h
@@ -47,6 +47,8 @@ void cobalt_thread_init(void);
int cobalt_thread_probe(pid_t pid);
+void cobalt_sched_init(void);
+
void cobalt_print_init(void);
void cobalt_print_init_atfork(void);
@@ -68,4 +70,10 @@ void cobalt_check_features(struct cobalt_featinfo *finfo);
extern struct sigaction __cobalt_orig_sigdebug;
+extern int __cobalt_std_fifo_minpri,
+ __cobalt_std_fifo_maxpri;
+
+extern int __cobalt_std_rr_minpri,
+ __cobalt_std_rr_maxpri;
+
#endif /* _LIB_COBALT_INTERNAL_H */
diff --git a/lib/cobalt/mutex.c b/lib/cobalt/mutex.c
index 9d8a914..1456099 100644
--- a/lib/cobalt/mutex.c
+++ b/lib/cobalt/mutex.c
@@ -99,6 +99,9 @@ void cobalt_mutex_init(void)
* mutex, increase CONFIG_XENO_OPT_SHARED_HEAPSZ for a process-shared
* mutex, or CONFIG_XENO_OPT_PRIVATE_HEAPSZ for a process-private mutex.
* - EAGAIN, no registry slot available, check/raise
CONFIG_XENO_OPT_REGISTRY_NRSLOTS.
+ * - ENOSYS, @a attr mentions priority protection
+ * (PTHREAD_PRIO_PROTECT), but the C library does not provide
+ * pthread_mutexattr_get/setprioceiling().
*
* @see
* <a
href="http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutex_init.html";>
@@ -117,7 +120,6 @@ COBALT_IMPL(int, pthread_mutex_init, (pthread_mutex_t
*mutex,
if (_mutex->magic == COBALT_MUTEX_MAGIC) {
err = -XENOMAI_SYSCALL1(sc_cobalt_mutex_check_init, _mutex);
-
if (err)
return err;
}
@@ -138,12 +140,19 @@ COBALT_IMPL(int, pthread_mutex_init, (pthread_mutex_t
*mutex,
err = pthread_mutexattr_getprotocol(attr, &tmp);
if (err)
return err;
- if (tmp == PTHREAD_PRIO_PROTECT) { /* Prio ceiling unsupported */
- err = EINVAL;
- return err;
- }
kmattr.protocol = tmp;
+ if (kmattr.protocol == PTHREAD_PRIO_PROTECT) {
+ err = pthread_mutexattr_getprioceiling(attr, &tmp);
+ if (err)
+ return err;
+ if (tmp == 0 || /* Could not cope with null minpri. */
+ tmp < __cobalt_std_fifo_minpri ||
+ tmp > __cobalt_std_fifo_maxpri)
+ return EINVAL;
+ kmattr.ceiling = tmp - 1;
+ }
+
err = -XENOMAI_SYSCALL2(sc_cobalt_mutex_init, _mutex, &kmattr);
if (err)
return err;
@@ -251,7 +260,7 @@ static int __attribute__((cold))
cobalt_mutex_autoinit(pthread_mutex_t *mutex)
*
* @return 0 on success
* @return an error number if:
- * - EPERM, the caller context is invalid;
+ * - EPERM, the caller is not allowed to perform the operation;
* - EINVAL, the mutex @a mx is invalid;
* - EPERM, the mutex is not process-shared and does not belong to the current
* process;
@@ -270,7 +279,8 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, ret;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -285,21 +295,28 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
* shadows and some debug features, so we must always obtain
* them via a syscall.
*/
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
+slow_path:
ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
if (ret == 0)
ret = -EBUSY;
}
- if (ret == -EBUSY)
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
+
switch(_mutex->attr.type) {
case PTHREAD_MUTEX_NORMAL:
break;
@@ -313,6 +330,7 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
++_mutex->lockcnt;
return 0;
}
+ }
do
ret = XENOMAI_SYSCALL1(sc_cobalt_mutex_lock, _mutex);
@@ -322,12 +340,22 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
_mutex->lockcnt = 1;
return -ret;
-
- autoinit:
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
+autoinit:
ret = cobalt_mutex_autoinit(mutex);
if (ret)
return ret;
- goto cont;
+ goto start;
}
/**
@@ -344,7 +372,7 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
*
* @return 0 on success;
* @return an error number if:
- * - EPERM, the caller context is invalid;
+ * - EPERM, the caller is not allowed to perform the operation;
* - EINVAL, the mutex @a mx is invalid;
* - EPERM, the mutex is not process-shared and does not belong to the current
* process;
@@ -366,7 +394,8 @@ COBALT_IMPL(int, pthread_mutex_timedlock, (pthread_mutex_t
*mutex,
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, ret;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -377,21 +406,28 @@ COBALT_IMPL(int, pthread_mutex_timedlock,
(pthread_mutex_t *mutex,
goto autoinit;
/* See __cobalt_pthread_mutex_lock() */
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
+slow_path:
ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
if (ret == 0)
ret = -EBUSY;
}
- if (ret == -EBUSY)
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
+
switch(_mutex->attr.type) {
case PTHREAD_MUTEX_NORMAL:
break;
@@ -406,6 +442,7 @@ COBALT_IMPL(int, pthread_mutex_timedlock, (pthread_mutex_t
*mutex,
++_mutex->lockcnt;
return 0;
}
+ }
do {
ret = XENOMAI_SYSCALL2(sc_cobalt_mutex_timedlock, _mutex, to);
@@ -414,12 +451,22 @@ COBALT_IMPL(int, pthread_mutex_timedlock,
(pthread_mutex_t *mutex,
if (ret == 0)
_mutex->lockcnt = 1;
return -ret;
-
- autoinit:
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
+autoinit:
ret = cobalt_mutex_autoinit(mutex);
if (ret)
return ret;
- goto cont;
+ goto start;
}
/**
@@ -433,7 +480,7 @@ COBALT_IMPL(int, pthread_mutex_timedlock, (pthread_mutex_t
*mutex,
*
* @return 0 on success;
* @return an error number if:
- * - EPERM, the caller context is invalid;
+ * - EPERM, the caller is not allowed to perform the operation;
* - EINVAL, the mutex is invalid;
* - EPERM, the mutex is not process-shared and does not belong to the current
* process;
@@ -451,7 +498,8 @@ COBALT_IMPL(int, pthread_mutex_trylock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, err;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -460,58 +508,75 @@ COBALT_IMPL(int, pthread_mutex_trylock, (pthread_mutex_t
*mutex))
if (_mutex->magic != COBALT_MUTEX_MAGIC)
goto autoinit;
-
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
- err = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
- if (err == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
+ ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
+ if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
- err = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
- if (err < 0)
+slow_path:
+ ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
+ if (ret < 0)
goto do_syscall;
- err = -EBUSY;
+ ret = -EBUSY;
}
- if (err == -EBUSY && _mutex->attr.type == PTHREAD_MUTEX_RECURSIVE) {
- if (_mutex->lockcnt == UINT32_MAX)
- return EAGAIN;
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
- ++_mutex->lockcnt;
- return 0;
+ if (_mutex->attr.type == PTHREAD_MUTEX_RECURSIVE) {
+ if (_mutex->lockcnt == UINT32_MAX)
+ return EAGAIN;
+
+ ++_mutex->lockcnt;
+ return 0;
+ }
}
return EBUSY;
do_syscall:
-
do {
- err = XENOMAI_SYSCALL1(sc_cobalt_mutex_trylock, _mutex);
- } while (err == -EINTR);
+ ret = XENOMAI_SYSCALL1(sc_cobalt_mutex_trylock, _mutex);
+ } while (ret == -EINTR);
- if (!err)
+ if (ret == 0)
_mutex->lockcnt = 1;
- return -err;
-
- autoinit:
- err = cobalt_mutex_autoinit(mutex);
- if (err)
- return err;
- goto cont;
+ return -ret;
+autoinit:
+ ret = cobalt_mutex_autoinit(mutex);
+ if (ret)
+ return ret;
+ goto start;
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
}
/**
* Unlock a mutex.
*
- * This service unlocks the mutex @a mx. If the mutex is of the @a
- * PTHREAD_MUTEX_RECURSIVE @a type and the locking recursion count is greater
- * than one, the lock recursion count is decremented and the mutex remains
- * locked.
+ * This service unlocks the @a mutex. If @a mutex is of the @a
+ * PTHREAD_MUTEX_RECURSIVE and the locking recursion count is greater
+ * than one, the lock recursion count is decremented and the mutex
+ * remains locked.
*
* Attempting to unlock a mutex which is not locked or which is locked by
* another thread than the current one yields the EPERM error, whatever the
@@ -521,8 +586,8 @@ do_syscall:
*
* @return 0 on success;
* @return an error number if:
- * - EPERM, the caller context is invalid;
- * - EINVAL, the mutex @a mx is invalid;
+ * - EPERM, the caller is not allowed to perform the operation;
+ * - EINVAL, the mutex @a mutex is invalid;
* - EPERM, the mutex was not locked by the current thread.
*
* @see
@@ -535,14 +600,14 @@ COBALT_IMPL(int, pthread_mutex_unlock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
+ struct xnthread_user_window *u_window;
struct cobalt_mutex_state *state;
xnhandle_t cur;
int err;
if (_mutex->magic != COBALT_MUTEX_MAGIC)
goto autoinit;
-
- cont:
+start:
cur = cobalt_get_current();
if (cur == XN_NO_HANDLE)
return EPERM;
@@ -562,21 +627,135 @@ COBALT_IMPL(int, pthread_mutex_unlock, (pthread_mutex_t
*mutex))
if (cobalt_get_current_mode() & (XNWEAK|XNDEBUG))
goto do_syscall;
- if (xnsynch_fast_release(&state->owner, cur))
+ if (xnsynch_fast_release(&state->owner, cur)) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto unprotect;
return 0;
+ }
do_syscall:
-
do {
err = XENOMAI_SYSCALL1(sc_cobalt_mutex_unlock, _mutex);
} while (err == -EINTR);
return -err;
- autoinit:
+autoinit:
err = cobalt_mutex_autoinit(mutex);
if (err)
return err;
- goto cont;
+ goto start;
+unprotect:
+ u_window = cobalt_get_current_window();
+ u_window->pp_pending = XN_NO_HANDLE;
+
+ return 0;
+}
+
+/**
+ * Set a mutex's priority ceiling.
+ *
+ * This routine acquires the specified mutex, then changes the
+ * associated priority ceiling value and releases it. @a prioceiling
+ * must be between the values returned by sched_get_priority_min() and
+ * sched_get_priority_max(), inclusive.
+ *
+ * The Cobalt implementation applies the priority ceiling protocol
+ * using the previous ceiling value during this operation. The new
+ * priority ceiling will apply next time the @a mutex transitions from
+ * the unlocked to locked state.
+ *
+ * @param mutex the target mutex.
+ *
+ * @param prioceiling the new ceiling value.
+ *
+ * @param old_ceiling on success and if this parameter is non-NULL,
+ * the previous ceiling value is copied to this address.
+ *
+ * @return 0 on success;
+ * @return an error number if:
+ * - EPERM, the caller is not allowed to perform the operation;
+ * - EINVAL, @a mutex is invalid;
+ * - EINVAL, @a mutex is not of type PTHREAD_PRIO_PROTECT;
+ * - EINVAL, @a prioceiling is out of range;
+ *
+ * @see
+ * <a
href="http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_setprioceiling.html";>
+ * Specification.</a>
+ *
+ * @apitags{xthread-only, switch-primary}
+ *
+ * @note If the calling thread's priority is higher than the mutex's
+ * new priority ceiling, the operation will nevertheless succeed; the
+ * Cobalt core never decreases the effective priority of a thread
+ * which locks a priority-protected mutex.
+ */
+COBALT_IMPL(int, pthread_mutex_setprioceiling,
+ (pthread_mutex_t *__restrict mutex,
+ int prioceiling, int *__restrict old_ceiling))
+{
+ struct cobalt_mutex_shadow *_mutex =
+ &((union cobalt_mutex_union *)mutex)->shadow_mutex;
+ struct cobalt_mutex_state *state;
+ int ret;
+
+ if (_mutex->magic != COBALT_MUTEX_MAGIC ||
+ _mutex->attr.protocol != PTHREAD_PRIO_PROTECT)
+ return EINVAL;
+
+ if (prioceiling < __cobalt_std_fifo_minpri ||
+ prioceiling > __cobalt_std_fifo_maxpri)
+ return EINVAL;
+
+ ret = __COBALT(pthread_mutex_lock(mutex));
+ if (ret)
+ return ret;
+
+ state = mutex_get_state(_mutex);
+ if (old_ceiling)
+ *old_ceiling = state->ceiling;
+
+ state->ceiling = prioceiling;
+
+ return __COBALT(pthread_mutex_unlock(mutex));
+}
+
+/**
+ * Get a mutex's priority ceiling.
+ *
+ * This routine retrieves the priority ceiling value of the specified
+ * mutex.
+ *
+ * @param mutex the target mutex.
+ *
+ * @param prioceiling on success, the current ceiling value is copied
+ * to this address.
+ *
+ * @return 0 on success;
+ * @return an error number if:
+ * - EINVAL, @a mutex is invalid;
+ * - EINVAL, @a mutex is not of type PTHREAD_PRIO_PROTECT;
+ *
+ * @see
+ * <a
href="http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_getprioceiling.html";>
+ * Specification.</a>
+ *
+ * @apitags{thread-unrestricted}
+ */
+COBALT_IMPL(int, pthread_mutex_getprioceiling,
+ (pthread_mutex_t *__restrict mutex, int *__restrict prioceiling))
+{
+ struct cobalt_mutex_shadow *_mutex =
+ &((union cobalt_mutex_union *)mutex)->shadow_mutex;
+ struct cobalt_mutex_state *state;
+
+ if (_mutex->magic != COBALT_MUTEX_MAGIC ||
+ _mutex->attr.protocol != PTHREAD_PRIO_PROTECT)
+ return EINVAL;
+
+ state = mutex_get_state(_mutex);
+ *prioceiling = state->ceiling;
+
+ return 0;
}
/**
@@ -692,9 +871,9 @@ int pthread_mutexattr_settype(pthread_mutexattr_t * attr,
int type);
* This service stores, at the address @a proto, the value of the @a protocol
* attribute in the mutex attributes object @a attr.
*
- * The @a protcol attribute may only be one of @a PTHREAD_PRIO_NONE or @a
- * PTHREAD_PRIO_INHERIT. See pthread_mutexattr_setprotocol() for the meaning of
- * these two constants.
+ * The @a protcol attribute may be one of @a PTHREAD_PRIO_NONE, @a
+ * PTHREAD_PRIO_INHERIT or @a PTHREAD_PRIO_PROTECT. See
+ * pthread_mutexattr_setprotocol() for the meaning of these constants.
*
* @param attr an initialized mutex attributes object;
*
@@ -727,8 +906,8 @@ int pthread_mutexattr_getprotocol(const pthread_mutexattr_t
* attr, int *proto);
* @a attr will not follow any priority protocol;
* - PTHREAD_PRIO_INHERIT, meaning that a mutex created with the attributes
* object @a attr, will follow the priority inheritance protocol.
- *
- * The value PTHREAD_PRIO_PROTECT (priority ceiling protocol) is unsupported.
+ * - PTHREAD_PRIO_PROTECT, meaning that a mutex created with the attributes
+ * object @a attr, will follow the priority protect protocol.
*
* @return 0 on success,
* @return an error number if:
diff --git a/lib/cobalt/sched.c b/lib/cobalt/sched.c
index 7376110..b0292b5 100644
--- a/lib/cobalt/sched.c
+++ b/lib/cobalt/sched.c
@@ -80,7 +80,11 @@ COBALT_IMPL(int, sched_yield, (void))
* <a
href="http://www.opengroup.org/onlinepubs/000095399/functions/sched_get_priority_min.html";>
* Specification.</a>
*
- * @apitags{thread-unrestricted}
+ * @apitags{thread-unrestricted, switch-secondary}
+ *
+ * @note Fetching the minimum priority level of SCHED_FIFO, SCHED_RR
+ * or any Xenomai-specific policy never leads to a mode switch. Any
+ * other value of @a policy may switch the caller to secondary mode.
*/
COBALT_IMPL(int, sched_get_priority_min, (int policy))
{
@@ -88,8 +92,9 @@ COBALT_IMPL(int, sched_get_priority_min, (int policy))
switch (policy) {
case SCHED_FIFO:
+ return __cobalt_std_fifo_minpri;
case SCHED_RR:
- break;
+ return __cobalt_std_rr_minpri;
default:
ret = XENOMAI_SYSCALL1(sc_cobalt_sched_minprio, policy);
if (ret >= 0)
@@ -152,7 +157,11 @@ int sched_get_priority_min_ex(int policy)
* <a
href="http://www.opengroup.org/onlinepubs/000095399/functions/sched_get_priority_max.html";>
* Specification.</a>
*
- * @apitags{thread-unrestricted}
+ * @apitags{thread-unrestricted, switch-secondary}
+ *
+ * @note Fetching the maximum priority level of SCHED_FIFO, SCHED_RR
+ * or any Xenomai-specific policy never leads to a mode switch. Any
+ * other value of @a policy may switch the caller to secondary mode.
*/
COBALT_IMPL(int, sched_get_priority_max, (int policy))
{
@@ -160,8 +169,9 @@ COBALT_IMPL(int, sched_get_priority_max, (int policy))
switch (policy) {
case SCHED_FIFO:
+ return __cobalt_std_fifo_maxpri;
case SCHED_RR:
- break;
+ return __cobalt_std_rr_maxpri;
default:
ret = XENOMAI_SYSCALL1(sc_cobalt_sched_maxprio, policy);
if (ret >= 0)
@@ -611,3 +621,18 @@ ssize_t sched_getconfig_np(int cpu, int policy,
}
/** @} */
+
+int __cobalt_std_fifo_minpri,
+ __cobalt_std_fifo_maxpri;
+
+int __cobalt_std_rr_minpri,
+ __cobalt_std_rr_maxpri;
+
+void cobalt_sched_init(void)
+{
+ /* Fill in the standard priority limit cache. */
+ __cobalt_std_fifo_minpri = __STD(sched_get_priority_min(SCHED_FIFO));
+ __cobalt_std_fifo_maxpri = __STD(sched_get_priority_max(SCHED_FIFO));
+ __cobalt_std_rr_minpri = __STD(sched_get_priority_min(SCHED_RR));
+ __cobalt_std_rr_maxpri = __STD(sched_get_priority_max(SCHED_RR));
+}
diff --git a/lib/cobalt/thread.c b/lib/cobalt/thread.c
index aab2c81..e6b3eae 100644
--- a/lib/cobalt/thread.c
+++ b/lib/cobalt/thread.c
@@ -50,7 +50,7 @@ int cobalt_xlate_schedparam(int policy,
const struct sched_param_ex *param_ex,
struct sched_param *param)
{
- int std_policy, priority, std_maxpri;
+ int std_policy, priority;
/*
* Translates Cobalt scheduling parameters to native ones,
@@ -77,9 +77,8 @@ int cobalt_xlate_schedparam(int policy,
* "weak" (negative) priorities - which are only
* meaningful for the Cobalt core - to regular values.
*/
- std_maxpri = __STD(sched_get_priority_max(SCHED_FIFO));
- if (priority > std_maxpri)
- priority = std_maxpri;
+ if (priority > __cobalt_std_fifo_maxpri)
+ priority = __cobalt_std_fifo_maxpri;
}
if (priority < 0)
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