[06/21] ARC: Atomics and Locking primitives

Message ID 1545167083-16764-7-git-send-email-vgupta@synopsys.com
State New
Headers show
Series
  • glibc port to ARC processors
Related show

Commit Message

Vineet Gupta Dec. 18, 2018, 9:04 p.m.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

---
 ChangeLog                                 |  3 ++
 sysdeps/arc/atomic-machine.h              | 89 +++++++++++++++++++++++++++++++
 sysdeps/arc/nptl/bits/pthreadtypes-arch.h | 72 +++++++++++++++++++++++++
 sysdeps/arc/nptl/bits/semaphore.h         | 32 +++++++++++
 4 files changed, 196 insertions(+)
 create mode 100644 sysdeps/arc/atomic-machine.h
 create mode 100644 sysdeps/arc/nptl/bits/pthreadtypes-arch.h
 create mode 100644 sysdeps/arc/nptl/bits/semaphore.h

-- 
2.7.4

Comments

Joseph Myers Dec. 18, 2018, 11:15 p.m. | #1
On Tue, 18 Dec 2018, Vineet Gupta wrote:

> +#define USE_ATOMIC_COMPILER_BUILTINS 0


There is a strong preference for new ports to use 1 for this rather than 0 
(and not to have any asms in their atomic-machine.h unless there's some 
reason use of built-in functions is unsuitable) - see the recently posted 
C-Sky version, for example.  If you can't use 1, there should be a good 
reason, documented in a comment, for using asms instead of compiler 
built-in functions (e.g. if the compiler built-in functions would result 
in libatomic dependencies, which are unsuitable for glibc, rather than 
being expanded inline).

-- 
Joseph S. Myers
joseph@codesourcery.com
Vineet Gupta Jan. 15, 2019, 12:40 a.m. | #2
On 12/18/18 3:15 PM, Joseph Myers wrote:
> On Tue, 18 Dec 2018, Vineet Gupta wrote:

> 

>> +#define USE_ATOMIC_COMPILER_BUILTINS 0

> 

> There is a strong preference for new ports to use 1 for this rather than 0 

> (and not to have any asms in their atomic-machine.h unless there's some 

> reason use of built-in functions is unsuitable) - see the recently posted 

> C-Sky version, for example.  If you can't use 1, there should be a good 

> reason, documented in a comment, for using asms instead of compiler 

> built-in functions (e.g. if the compiler built-in functions would result 

> in libatomic dependencies, which are unsuitable for glibc, rather than 

> being expanded inline).


I tried switching to builtins and see the resulting differences in generated code:
there's one snafu to begin with: gcc seems to be generating a DMB 0 for the
barriers, which is a no-op, it needs to be DMB {1,2,3} for read, write, control...
so that needs fixing there.

Patch

diff --git a/ChangeLog b/ChangeLog
index 6e53b171a72d..d2f6cd2d0d09 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,9 @@ 
 	* sysdeps/arc/nptl/tcb-offsets.sym: New file.
 	* sysdeps/arc/nptl/tls.h: New file.
 	* sysdeps/arc/stackinfo.h: New file.
+	* sysdeps/arc/atomic-machine.h: New file.
+	* sysdeps/arc/nptl/bits/pthreadtypes-arch.h: New file.
+	* sysdeps/arc/nptl/bits/semaphore.h: New file.
 
 2018-12-17  Joseph Myers  <joseph@codesourcery.com>
 
diff --git a/sysdeps/arc/atomic-machine.h b/sysdeps/arc/atomic-machine.h
new file mode 100644
index 000000000000..1a8d976794d0
--- /dev/null
+++ b/sysdeps/arc/atomic-machine.h
@@ -0,0 +1,89 @@ 
+/* Low-level functions for atomic operations. ARC version.
+   Copyright (C) 2012-2018 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 _ARC_BITS_ATOMIC_H
+#define _ARC_BITS_ATOMIC_H 1
+
+#include <stdint.h>
+
+typedef int32_t atomic32_t;
+typedef uint32_t uatomic32_t;
+typedef int_fast32_t atomic_fast32_t;
+typedef uint_fast32_t uatomic_fast32_t;
+
+typedef intptr_t atomicptr_t;
+typedef uintptr_t uatomicptr_t;
+typedef intmax_t atomic_max_t;
+typedef uintmax_t uatomic_max_t;
+
+#define __HAVE_64B_ATOMICS 0
+#define USE_ATOMIC_COMPILER_BUILTINS 0
+#define ATOMIC_EXCHANGE_USES_CAS 1
+
+#define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval)	\
+  (abort (), (__typeof (*mem)) 0)
+#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval)	\
+  (abort (), (__typeof (*mem)) 0)
+#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval)	\
+  (abort (), (__typeof (*mem)) 0)
+
+#define __arch_compare_and_exchange_bool_8_acq(mem, newval, oldval)	\
+  (abort (), 0)
+#define __arch_compare_and_exchange_bool_16_acq(mem, newval, oldval)	\
+  (abort (), 0)
+#define __arch_compare_and_exchange_bool_64_acq(mem, newval, oldval)	\
+  (abort (), 0)
+
+#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval)	\
+  ({									\
+	__typeof(*(mem)) prev;						\
+									\
+	__asm__ __volatile__(						\
+	"1:	llock   %0, [%1]	\n"				\
+	"	brne    %0, %2, 2f	\n"				\
+	"	scond   %3, [%1]	\n"				\
+	"	bnz     1b		\n"				\
+	"2:				\n"				\
+	: "=&r"(prev)							\
+	: "r"(mem), "ir"(oldval),					\
+	  "r"(newval) /* can't be "ir". scond can't take limm for "b" */\
+	: "cc", "memory");						\
+									\
+	prev;								\
+  })
+
+# define atomic_exchange_acq(mem, newvalue) \
+  ({									\
+	__typeof(*(mem)) __val = (newvalue);				\
+									\
+	__asm__ __volatile__(						\
+	"1:	ex   %0, [%1]	\n"					\
+	: "+r"(__val)							\
+	: "r"(mem)							\
+	: "memory");							\
+									\
+	__val;								\
+  })
+
+#ifdef __ARC700__
+#define atomic_full_barrier()  ({ asm volatile ("sync":::"memory"); })
+#else
+#define atomic_full_barrier()  ({ asm volatile ("dmb 3":::"memory"); })
+#endif
+
+#endif /* _ARC_BITS_ATOMIC_H */
diff --git a/sysdeps/arc/nptl/bits/pthreadtypes-arch.h b/sysdeps/arc/nptl/bits/pthreadtypes-arch.h
new file mode 100644
index 000000000000..473d9ec2bf0d
--- /dev/null
+++ b/sysdeps/arc/nptl/bits/pthreadtypes-arch.h
@@ -0,0 +1,72 @@ 
+/* Machine-specific pthread type layouts.  ARC version.
+   Copyright (C) 2012-2018 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 _BITS_PTHREADTYPES_ARCH_H
+#define _BITS_PTHREADTYPES_ARCH_H	1
+
+#include <endian.h>
+
+#define __SIZEOF_PTHREAD_ATTR_T 36
+#define __SIZEOF_PTHREAD_MUTEX_T 24
+#define __SIZEOF_PTHREAD_MUTEXATTR_T 4
+#define __SIZEOF_PTHREAD_COND_T 48
+#define __SIZEOF_PTHREAD_CONDATTR_T 4
+#define __SIZEOF_PTHREAD_RWLOCK_T 32
+#define __SIZEOF_PTHREAD_RWLOCKATTR_T 8
+#define __SIZEOF_PTHREAD_BARRIER_T 20
+#define __SIZEOF_PTHREAD_BARRIERATTR_T 4
+
+/* Data structure for mutex handling. */
+#define __PTHREAD_COMPAT_PADDING_MID
+#define __PTHREAD_COMPAT_PADDING_END
+#define __PTHREAD_MUTEX_LOCK_ELISION    0
+#define __PTHREAD_MUTEX_NUSERS_AFTER_KIND  1
+#define __PTHREAD_MUTEX_USE_UNION          1
+
+#define __LOCK_ALIGNMENT
+#define __ONCE_ALIGNMENT
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#if __BYTE_ORDER == __BIG_ENDIAN
+  unsigned char __pad1;
+  unsigned char __pad2;
+  unsigned char __shared;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+#else
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  unsigned char __shared;
+  unsigned char __pad1;
+  unsigned char __pad2;
+#endif
+  int __cur_writer;
+};
+
+#define __PTHREAD_RWLOCK_ELISION_EXTRA 0
+
+#endif	/* bits/pthreadtypes-arch.h */
diff --git a/sysdeps/arc/nptl/bits/semaphore.h b/sysdeps/arc/nptl/bits/semaphore.h
new file mode 100644
index 000000000000..1ecc8ab8a65b
--- /dev/null
+++ b/sysdeps/arc/nptl/bits/semaphore.h
@@ -0,0 +1,32 @@ 
+/* Machine-specific POSIX semaphore type layouts.  ARC version.
+   Copyright (C) 2002-2018 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 _SEMAPHORE_H
+# error "Never use <bits/semaphore.h> directly; include <semaphore.h> instead."
+#endif
+
+#define __SIZEOF_SEM_T	16
+
+/* Value returned if `sem_open' failed.  */
+#define SEM_FAILED      ((sem_t *) 0)
+
+typedef union
+{
+  char __size[__SIZEOF_SEM_T];
+  long int __align;
+} sem_t;