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authorAgustina Arzille <avarzille@riseup.net>2018-03-18 18:22:55 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2018-03-18 18:23:45 +0100
commitfb4cc8a0c2cc7ca710a2e1b21d33fcf7c5e3e8ba (patch)
tree0144983157b1b454724c37fe9e3e2b1e4aaa6629 /mach
parent542c20a171cbc8cb63155fa6344708d26e9c446b (diff)
downloadglibc-fb4cc8a0c2cc7ca710a2e1b21d33fcf7c5e3e8ba.tar.gz
hurd: Reimplement libc locks using mach's gsync
* hurd/Makefile (routines): Add hurdlock. * hurd/Versions (GLIBC_PRIVATE): Added new entry to export the above interface. (HURD_CTHREADS_0.3): Remove __libc_getspecific. * hurd/hurdpid.c: Include <lowlevellock.h> (_S_msg_proc_newids): Use lll_wait to synchronize. * hurd/hurdsig.c: (reauth_proc): Use __mutex_lock and __mutex_unlock. * hurd/setauth.c: Include <hurdlock.h>, use integer for synchronization. * mach/Makefile (lock-headers): Remove machine-lock.h. * mach/lock-intern.h: Include <lowlevellock.h> instead of <machine-lock.h>. (__spin_lock_t): New type. (__SPIN_LOCK_INITIALIZER): New macro. (__spin_lock, __spin_unlock, __spin_try_lock, __spin_lock_locked, __mutex_init, __mutex_lock_solid, __mutex_unlock_solid, __mutex_lock, __mutex_unlock, __mutex_trylock): Use lll to implement locks. * mach/mutex-init.c: Include <lowlevellock.h> instead of <cthreads.h>. (__mutex_init): Initialize with lll. * manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): New errno values. * sysdeps/mach/Makefile: Add libmachuser as dependencies for libs needing lll. * sysdeps/mach/hurd/bits/errno.h: Regenerate. * sysdeps/mach/hurd/cthreads.c (__libc_getspecific): Remove function. * sysdeps/mach/hurd/bits/libc-lock.h: Remove file. * sysdeps/mach/hurd/setpgid.c: Include <lowlevellock.h>. (__setpgid): Use lll for synchronization. * sysdeps/mach/hurd/setsid.c: Likewise with __setsid. * sysdeps/mach/bits/libc-lock.h: Include <tls.h> and <lowlevellock.h> instead of <cthreads.h>. (_IO_lock_inexpensive): New macro (__libc_lock_recursive_t, __rtld_lock_recursive_t): New structures. (__libc_lock_self0): New declaration. (__libc_lock_owner_self): New macro. (__libc_key_t): Remove type. (_LIBC_LOCK_INITIALIZER): New macro. (__libc_lock_define_initialized, __libc_lock_init, __libc_lock_fini, __libc_lock_fini_recursive, __rtld_lock_fini_recursive, __libc_lock_lock, __libc_lock_trylock, __libc_lock_unlock, __libc_lock_define_initialized_recursive, __rtld_lock_define_initialized_recursive, __libc_lock_init_recursive, __libc_lock_trylock_recursive, __libc_lock_lock_recursive, __libc_lock_unlock_recursive, __rtld_lock_initialize, __rtld_lock_trylock_recursive, __rtld_lock_lock_recursive, __rtld_lock_unlock_recursive __libc_once_define, __libc_mutex_unlock): Reimplement with lll. (__libc_lock_define_recursive, __rtld_lock_define_recursive, _LIBC_LOCK_RECURSIVE_INITIALIZER, _RTLD_LOCK_RECURSIVE_INITIALIZER): New macros. Include <libc-lockP.h> to reimplement libc_key* with pthread_key*. * hurd/hurdlock.c: New file. * hurd/hurdlock.h: New file. * mach/lowlevellock.h: New file
Diffstat (limited to 'mach')
-rw-r--r--mach/Makefile2
-rw-r--r--mach/lock-intern.h69
-rw-r--r--mach/lowlevellock.h81
-rw-r--r--mach/mutex-init.c7
4 files changed, 129 insertions, 30 deletions
diff --git a/mach/Makefile b/mach/Makefile
index e0d1ffb1fa..2683587b2d 100644
--- a/mach/Makefile
+++ b/mach/Makefile
@@ -23,7 +23,7 @@ headers = mach_init.h mach.h mach_error.h mach-shortcuts.h mach/mach_traps.h \
$(interface-headers) mach/mach.h mach/mig_support.h mach/error.h \
$(lock-headers) machine-sp.h bits/mach/param.h
lock = spin-solid spin-lock mutex-init mutex-solid
-lock-headers = lock-intern.h machine-lock.h spin-lock.h
+lock-headers = lock-intern.h spin-lock.h
routines = $(mach-syscalls) $(mach-shortcuts) \
mach_init mig_strncpy msg \
mig-alloc mig-dealloc mig-reply \
diff --git a/mach/lock-intern.h b/mach/lock-intern.h
index f8874c7561..ed8acb6aec 100644
--- a/mach/lock-intern.h
+++ b/mach/lock-intern.h
@@ -19,12 +19,19 @@
#define _LOCK_INTERN_H
#include <sys/cdefs.h>
-#include <machine-lock.h>
+#if defined __USE_EXTERN_INLINES && defined _LIBC
+# include <lowlevellock.h>
+#endif
#ifndef _EXTERN_INLINE
#define _EXTERN_INLINE __extern_inline
#endif
+/* The type of a spin lock variable. */
+typedef unsigned int __spin_lock_t;
+
+/* Static initializer for spinlocks. */
+#define __SPIN_LOCK_INITIALIZER LLL_INITIALIZER
/* Initialize LOCK. */
@@ -50,31 +57,47 @@ extern void __spin_lock (__spin_lock_t *__lock);
_EXTERN_INLINE void
__spin_lock (__spin_lock_t *__lock)
{
- if (! __spin_try_lock (__lock))
- __spin_lock_solid (__lock);
+ lll_lock (__lock, 0);
}
#endif
-
-/* Name space-clean internal interface to mutex locks.
- Code internal to the C library uses these functions to lock and unlock
- mutex locks. These locks are of type `struct mutex', defined in
- <cthreads.h>. The functions here are name space-clean. If the program
- is linked with the cthreads library, `__mutex_lock_solid' and
- `__mutex_unlock_solid' will invoke the corresponding cthreads functions
- to implement real mutex locks. If not, simple stub versions just use
- spin locks. */
+/* Unlock LOCK. */
+extern void __spin_unlock (__spin_lock_t *__lock);
+#if defined __USE_EXTERN_INLINES && defined _LIBC
+_EXTERN_INLINE void
+__spin_unlock (__spin_lock_t *__lock)
+{
+ lll_unlock (__lock, 0);
+}
+#endif
-/* Initialize the newly allocated mutex lock LOCK for further use. */
-extern void __mutex_init (void *__lock);
+/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
+extern int __spin_try_lock (__spin_lock_t *__lock);
-/* Lock LOCK, blocking if we can't get it. */
-extern void __mutex_lock_solid (void *__lock);
+#if defined __USE_EXTERN_INLINES && defined _LIBC
+_EXTERN_INLINE int
+__spin_try_lock (__spin_lock_t *__lock)
+{
+ return (lll_trylock (__lock) == 0);
+}
+#endif
+
+/* Return nonzero if LOCK is locked. */
+extern int __spin_lock_locked (__spin_lock_t *__lock);
-/* Finish unlocking LOCK, after the spin lock LOCK->held has already been
- unlocked. This function will wake up any thread waiting on LOCK. */
-extern void __mutex_unlock_solid (void *__lock);
+#if defined __USE_EXTERN_INLINES && defined _LIBC
+_EXTERN_INLINE int
+__spin_lock_locked (__spin_lock_t *__lock)
+{
+ return (*(volatile __spin_lock_t *)__lock != 0);
+}
+#endif
+
+/* Name space-clean internal interface to mutex locks. */
+
+/* Initialize the newly allocated mutex lock LOCK for further use. */
+extern void __mutex_init (void *__lock);
/* Lock the mutex lock LOCK. */
@@ -84,8 +107,7 @@ extern void __mutex_lock (void *__lock);
_EXTERN_INLINE void
__mutex_lock (void *__lock)
{
- if (! __spin_try_lock ((__spin_lock_t *) __lock))
- __mutex_lock_solid (__lock);
+ __spin_lock ((__spin_lock_t *)__lock);
}
#endif
@@ -97,8 +119,7 @@ extern void __mutex_unlock (void *__lock);
_EXTERN_INLINE void
__mutex_unlock (void *__lock)
{
- __spin_unlock ((__spin_lock_t *) __lock);
- __mutex_unlock_solid (__lock);
+ __spin_unlock ((__spin_lock_t *)__lock);
}
#endif
@@ -109,7 +130,7 @@ extern int __mutex_trylock (void *__lock);
_EXTERN_INLINE int
__mutex_trylock (void *__lock)
{
- return __spin_try_lock ((__spin_lock_t *) __lock);
+ return (__spin_try_lock ((__spin_lock_t *)__lock));
}
#endif
diff --git a/mach/lowlevellock.h b/mach/lowlevellock.h
new file mode 100644
index 0000000000..20c66ca979
--- /dev/null
+++ b/mach/lowlevellock.h
@@ -0,0 +1,81 @@
+/* Low-level lock implementation. Mach gsync-based version.
+ Copyright (C) 1994-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _MACH_LOWLEVELLOCK_H
+#define _MACH_LOWLEVELLOCK_H 1
+
+#include <mach/gnumach.h>
+#include <atomic.h>
+
+/* Gsync flags. */
+#ifndef GSYNC_SHARED
+ #define GSYNC_SHARED 0x01
+ #define GSYNC_QUAD 0x02
+ #define GSYNC_TIMED 0x04
+ #define GSYNC_BROADCAST 0x08
+ #define GSYNC_MUTATE 0x10
+#endif
+
+/* Static initializer for low-level locks. */
+#define LLL_INITIALIZER 0
+
+/* Wait on address PTR, without blocking if its contents
+ * are different from VAL. */
+#define lll_wait(ptr, val, flags) \
+ __gsync_wait (__mach_task_self (), \
+ (vm_offset_t)(ptr), (val), 0, 0, (flags))
+
+/* Wake one or more threads waiting on address PTR. */
+#define lll_wake(ptr, flags) \
+ __gsync_wake (__mach_task_self (), (vm_offset_t)(ptr), 0, (flags))
+
+/* Acquire the lock at PTR. */
+#define lll_lock(ptr, flags) \
+ ({ \
+ int *__iptr = (int *)(ptr); \
+ int __flags = (flags); \
+ if (*__iptr != 0 || \
+ atomic_compare_and_exchange_bool_acq (__iptr, 1, 0) != 0) \
+ while (1) \
+ { \
+ if (atomic_exchange_acq (__iptr, 2) == 0) \
+ break; \
+ lll_wait (__iptr, 2, __flags); \
+ } \
+ (void)0; \
+ })
+
+/* Try to acquire the lock at PTR, without blocking.
+ Evaluates to zero on success. */
+#define lll_trylock(ptr) \
+ ({ \
+ int *__iptr = (int *)(ptr); \
+ *__iptr == 0 && \
+ atomic_compare_and_exchange_bool_acq (__iptr, 1, 0) == 0 ? 0 : -1; \
+ })
+
+/* Release the lock at PTR. */
+#define lll_unlock(ptr, flags) \
+ ({ \
+ int *__iptr = (int *)(ptr); \
+ if (atomic_exchange_rel (__iptr, 0) == 2) \
+ lll_wake (__iptr, (flags)); \
+ (void)0; \
+ })
+
+#endif
diff --git a/mach/mutex-init.c b/mach/mutex-init.c
index cab0a86fec..776fec5506 100644
--- a/mach/mutex-init.c
+++ b/mach/mutex-init.c
@@ -17,13 +17,10 @@
<http://www.gnu.org/licenses/>. */
#include <lock-intern.h>
-#include <cthreads.h>
+#include <lowlevellock.h>
void
__mutex_init (void *lock)
{
- /* This happens to be name space-safe because it is a macro.
- It invokes only spin_lock_init, which is a macro for __spin_lock_init;
- and cthread_queue_init, which is a macro for some simple code. */
- mutex_init ((struct mutex *) lock);
+ *(int *)lock = LLL_INITIALIZER;
}