2021-01-04 17:26:59 +08:00
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/* Copyright (C) 2012-2021 Free Software Foundation, Inc.
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2012-05-01 23:48:28 +08:00
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Atomic Library (libatomic).
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Libatomic is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include "libatomic_i.h"
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/* If we natively support the cas, and if we're unconcerned with extra
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barriers (e.g. fully in-order cpu for which barriers are a nop), then
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go ahead and expand the operation inline. */
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#if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
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# define EXACT_INLINE(N) \
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if (C2(HAVE_ATOMIC_CAS_,N)) \
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return __atomic_compare_exchange_n \
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Avoid non constant memory model uses in libatomic
x86 ends up using non constant memory models for some of the libatomic
functions. These all end up as __ATOMIC_SEQ_CST. Just use this
directly. This avoids a new warning for non constant memory
models, which broke the bootstrap with -Werror
Passed bootstrap and test on x86_64-linux.
libatomic/:
2013-03-23 Andi Kleen <ak@linux.intel.com>
* gcas.c: (EXACT_INLINE): Use __ATOMIC_SEQ_CST.
* gexch.c: (EXACT_INLINE): Use __ATOMIC_SEQ_CST.
* gload.c: (EXACT_INLINE): Use __ATOMIC_SEQ_CST.
* gstore.c: (EXACT_INLINE): Use __ATOMIC_SEQ_CST.
diff --git a/libatomic/gcas.c b/libatomic/gcas.c
index edbf611..e3d77f3 100644
--- a/libatomic/gcas.c
+++ b/libatomic/gcas.c
@@ -32,7 +32,7 @@
# define EXACT_INLINE(N) \
if (C2(HAVE_ATOMIC_CAS_,N)) \
return __atomic_compare_exchange_n \
- (PTR(N,mptr), PTR(N,eptr), *PTR(N,dptr), false, smodel, fmodel)
+ (PTR(N,mptr), PTR(N,eptr), *PTR(N,dptr), false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
#else
# define EXACT_INLINE(N)
#endif
diff --git a/libatomic/gexch.c b/libatomic/gexch.c
index 1999067..c8c8658 100644
--- a/libatomic/gexch.c
+++ b/libatomic/gexch.c
@@ -33,7 +33,7 @@
if (C2(HAVE_ATOMIC_EXCHANGE_,N)) \
{ \
*PTR(N,rptr) = __atomic_exchange_n \
- (PTR(N,mptr), *PTR(N,vptr), smodel); \
+ (PTR(N,mptr), *PTR(N,vptr), __ATOMIC_SEQ_CST); \
return; \
}
#else
diff --git a/libatomic/gload.c b/libatomic/gload.c
index df318d5..85865bd 100644
--- a/libatomic/gload.c
+++ b/libatomic/gload.c
@@ -32,7 +32,7 @@
# define EXACT_INLINE(N, DEST, SRC, DONE) \
if (C2(HAVE_ATOMIC_LDST_,N)) \
{ \
- DEST = __atomic_load_n (SRC, smodel); \
+ DEST = __atomic_load_n (SRC, __ATOMIC_SEQ_CST); \
DONE; \
}
#else
diff --git a/libatomic/gstore.c b/libatomic/gstore.c
index d571e58..84f9a8d 100644
--- a/libatomic/gstore.c
+++ b/libatomic/gstore.c
@@ -32,7 +32,7 @@
# define EXACT_INLINE(N) \
if (C2(HAVE_ATOMIC_LDST_,N)) \
{ \
- __atomic_store_n (PTR(N,mptr), *PTR(N,vptr), smodel); \
+ __atomic_store_n (PTR(N,mptr), *PTR(N,vptr), __ATOMIC_SEQ_CST); \
return; \
}
#else
From-SVN: r197017
2013-03-24 08:23:10 +08:00
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(PTR(N,mptr), PTR(N,eptr), *PTR(N,dptr), false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
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2012-05-01 23:48:28 +08:00
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#else
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# define EXACT_INLINE(N)
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#endif
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/* ... and if all that fails, invoke the function we generated elsewhere.
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Worst case, this will *also* use locks. */
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#define EXACT(N) \
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do { \
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if (!C2(HAVE_INT,N)) break; \
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if ((uintptr_t)mptr & (N - 1)) break; \
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EXACT_INLINE (N); \
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return C3(local_,compare_exchange_,N) \
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(PTR(N,mptr), PTR(N,eptr), *PTR(N,dptr), smodel, fmodel); \
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} while (0)
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#define LARGER(N) \
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do { \
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if (!C2(HAVE_INT,N)) break; \
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if (!C2(HAVE_ATOMIC_LDST_,N)) break; \
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if (!C2(MAYBE_HAVE_ATOMIC_CAS_,N)) break; \
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r = (uintptr_t)mptr & (N - 1); \
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a = (uintptr_t)mptr & -N; \
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if (r + n <= N) \
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{ \
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pre_barrier (smodel); \
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u.C2(i,N) = __atomic_load_n (PTR(N,a), __ATOMIC_RELAXED); \
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do { \
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if (memcmp (u.b + r, eptr, n) != 0) goto Lfail; \
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v = u; memcpy (v.b + r, dptr, n); \
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} while (!(C2(HAVE_ATOMIC_CAS_,N) \
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? __atomic_compare_exchange_n (PTR(N,a), \
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&u.C2(i,N), v.C2(i,N), true, \
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__ATOMIC_RELAXED, __ATOMIC_RELAXED) \
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: C3(local_,compare_exchange_,N) (PTR(N,a), \
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&u.C2(i,N), v.C2(i,N), \
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__ATOMIC_RELAXED, __ATOMIC_RELAXED))); \
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goto Lsucc; \
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} \
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} while (0)
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bool
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libat_compare_exchange (size_t n, void *mptr, void *eptr, void *dptr,
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int smodel, int fmodel)
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{
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union max_size_u u, v;
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uintptr_t r, a;
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bool ret;
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switch (n)
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{
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case 0: return true;
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case 1: EXACT(1); goto L4;
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case 2: EXACT(2); goto L4;
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case 4: EXACT(4); goto L8;
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case 8: EXACT(8); goto L16;
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case 16: EXACT(16); break;
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case 3: L4: LARGER(4); /* FALLTHRU */
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case 5 ... 7: L8: LARGER(8); /* FALLTHRU */
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case 9 ... 15: L16: LARGER(16); break;
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Lsucc:
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post_barrier (smodel);
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return true;
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Lfail:
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post_barrier (fmodel);
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memcpy (eptr, u.b + r, n);
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return false;
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}
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pre_seq_barrier (smodel);
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libat_lock_n (mptr, n);
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ret = memcmp (mptr, eptr, n) == 0;
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memcpy ((ret ? mptr : eptr), (ret ? dptr : mptr), n);
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libat_unlock_n (mptr, n);
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post_seq_barrier (ret ? smodel : fmodel);
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return ret;
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}
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EXPORT_ALIAS (compare_exchange);
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