From: Dinar Temirbulatov <dtemirbulatov@gmail.com>
To: Abhishek Deb <adeb@nvidia.com>
Cc: Joseph Myers <joseph@codesourcery.com>,
"libc-ports@sourceware.org" <libc-ports@sourceware.org>,
Maxim Kuvyrkov <maxim@kugelworks.com>
Subject: Re: [Patch] ARM define atomic_exchange_acq/atomic_exchange_rel to __atomic_exchange_n
Date: Wed, 11 Sep 2013 19:27:00 -0000 [thread overview]
Message-ID: <CAMnfPmMsJUFLf3EfEn7kNccQnWStPRtSS916_P8TG59S9dbtAg@mail.gmail.com> (raw)
In-Reply-To: <0E42B6C0C4628E48B8DF5D3F3C8FCA8898F2CF5F17@HQMAIL02.nvidia.com>
[-- Attachment #1: Type: text/plain, Size: 483 bytes --]
Hi,
Another updated version of the change with just eliminated $. Tested
glibc internal testsuite with: 1) arm v4t gcc-4.5.3 with
__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 undefined (kernel helpers only)
with no new regrssions, 2) arm with FSF gcc-4.6.4 on armv7-a with
__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 defined with no new regrssions, 3)
arm FSF gcc-4.7.3 on armv7-a with __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
with no new regressions. Ok to commit?
thanks, Dinar.
[-- Attachment #2: arm_atomic8.patch --]
[-- Type: application/octet-stream, Size: 5430 bytes --]
--- glibc-orig/ports/sysdeps/arm/bits/atomic.h 2013-08-19 21:46:44.592731210 +0400
+++ glibc/ports/sysdeps/arm/bits/atomic.h 2013-09-05 23:16:18.336235291 +0400
@@ -35,9 +35,6 @@ typedef uintmax_t uatomic_max_t;
void __arm_link_error (void);
-/* Use the atomic builtins provided by GCC in case the backend provides
- a pattern to do this efficiently. */
-
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
# define atomic_full_barrier() __sync_synchronize ()
#else
@@ -51,9 +48,88 @@ void __arm_link_error (void);
# define __arm_assisted_full_barrier() __arm_link_error()
#endif
-/* Atomic compare and exchange. */
+/* Use the atomic builtins provided by GCC in case the backend provides
+ a pattern to do this efficiently. */
+#if __GNUC_PREREQ (4, 7) && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
-#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+# define atomic_exchange_acq(mem, value) \
+ __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
+
+# define atomic_exchange_rel(mem, value) \
+ __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
+
+/* Atomic exchange (without compare). */
+
+# define __arch_exchange_8_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+# define __arch_exchange_16_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+# define __arch_exchange_32_int(mem, newval, model) \
+ __atomic_exchange_n (mem, newval, model)
+
+# define __arch_exchange_64_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+/* Compare and exchange with "acquire" semantics, ie barrier after. */
+
+# define atomic_compare_and_exchange_bool_acq(mem, new, old) \
+ __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
+ mem, new, old, __ATOMIC_ACQUIRE)
+
+# define atomic_compare_and_exchange_val_acq(mem, new, old) \
+ __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
+ mem, new, old, __ATOMIC_ACQUIRE)
+
+/* Compare and exchange with "release" semantics, ie barrier before. */
+
+# define atomic_compare_and_exchange_bool_rel(mem, new, old) \
+ __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
+ mem, new, old, __ATOMIC_RELEASE)
+
+# define atomic_compare_and_exchange_val_rel(mem, new, old) \
+ __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
+ mem, new, old, __ATOMIC_RELEASE)
+
+/* Compare and exchange.
+ For all "bool" routines, we return FALSE if exchange succesful. */
+
+# define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
+ ({ \
+ typeof (*mem) __oldval = (oldval); \
+ !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
+ model, __ATOMIC_RELAXED); \
+ })
+
+# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
+ ({ \
+ typeof (*mem) __oldval = (oldval); \
+ __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
+ model, __ATOMIC_RELAXED); \
+ __oldval; \
+ })
+
+# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+#elif defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+/* Atomic compare and exchange. */
# define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
__sync_val_compare_and_swap ((mem), (oldval), (newval))
#else
@@ -61,16 +137,18 @@ void __arm_link_error (void);
__arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval))
#endif
+#if !__GNUC_PREREQ (4, 7) || !defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
/* We don't support atomic operations on any non-word types.
So make them link errors. */
-#define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
-#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
-#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
+#endif
/* An OS-specific bits/atomic.h file will define this macro if
the OS can provide something. If not, we'll fail to build
next prev parent reply other threads:[~2013-09-11 19:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-01 20:43 Dinar Temirbulatov
2013-09-02 15:08 ` Joseph S. Myers
2013-09-03 17:31 ` Abhishek Deb
2013-09-05 12:56 ` Dinar Temirbulatov
2013-09-05 15:48 ` Joseph S. Myers
2013-09-05 17:09 ` Abhishek Deb
2013-09-11 19:25 ` Dinar Temirbulatov
2013-09-11 19:27 ` Dinar Temirbulatov [this message]
2013-09-11 20:40 ` Abhishek Deb
2013-09-13 17:14 ` Joseph S. Myers
2013-09-14 3:29 ` Dinar Temirbulatov
2013-09-18 17:16 ` Joseph S. Myers
2013-09-19 6:53 ` Maxim Kuvyrkov
2013-09-19 16:29 ` Joseph S. Myers
-- strict thread matches above, loose matches on Subject: below --
2013-09-01 20:42 Dinar Temirbulatov
2013-08-13 17:11 Dinar Temirbulatov
2013-08-15 21:46 ` Abhishek Deb
2013-08-16 22:57 ` Dinar Temirbulatov
2013-08-17 2:42 ` Abhishek Deb
2013-08-19 19:21 ` Dinar Temirbulatov
2013-08-18 20:29 ` Joseph S. Myers
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