From b6a4e64a88a223b8f418be64de9f9c9fe29ab528 Mon Sep 17 00:00:00 2001
From: Nitin Garg <nitingarg98@gmail.com>
Date: Tue, 1 Feb 2011 10:57:34 -0600
Subject: [PATCH] [SIGNED-FF] Add ARM atomic functions


Signed-off-by: Nitin Garg <nitingarg98@gmail.com>
---
 uClibc/libc/sysdeps/linux/arm/bits/atomic.h        |  110 ++++++++++++++++++
 .../nptl/sysdeps/unix/sysv/linux/arm/bits/atomic.h |  122 --------------------
 2 files changed, 110 insertions(+), 122 deletions(-)
 create mode 100644 uClibc/libc/sysdeps/linux/arm/bits/atomic.h
 delete mode 100644 uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/arm/bits/atomic.h

diff --git a/uClibc/libc/sysdeps/linux/arm/bits/atomic.h b/uClibc/libc/sysdeps/linux/arm/bits/atomic.h
new file mode 100644
index 0000000..523c3be
--- /dev/null
+++ b/uClibc/libc/sysdeps/linux/arm/bits/atomic.h
@@ -0,0 +1,110 @@
+/* Copyright (C) 2002, 2003, 2004, 2005 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stdint.h>
+#include <sysdep.h>
+
+
+typedef int8_t atomic8_t;
+typedef uint8_t uatomic8_t;
+typedef int_fast8_t atomic_fast8_t;
+typedef uint_fast8_t uatomic_fast8_t;
+
+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;
+
+void __arm_link_error (void);
+
+#define atomic_exchange_acq(mem, newvalue)				      \
+  ({ __typeof (*mem) _xchg_result;					      \
+     if (sizeof (*mem) == 1)						      \
+       __asm__ __volatile__ ("swpb %0, %1, [%2]"			      \
+			     : "=&r,&r" (_xchg_result)			      \
+			     : "r,0" (newvalue), "r,r" (mem) : "memory");     \
+     else if (sizeof (*mem) == 4)					      \
+       __asm__ __volatile__ ("swp %0, %1, [%2]"				      \
+			     : "=&r,&r" (_xchg_result)			      \
+			     : "r,0" (newvalue), "r,r" (mem) : "memory");     \
+     else								      \
+       {								      \
+	 _xchg_result = 0;						      \
+	 abort ();							      \
+       }								      \
+     _xchg_result; })
+
+/* Atomic compare and exchange.  These sequences are not actually atomic;
+   there is a race if *MEM != OLDVAL and we are preempted between the two
+   swaps.  However, they are very close to atomic, and are the best that a
+   pre-ARMv6 implementation can do without operating system support.
+   LinuxThreads has been using these sequences for many years.  */
+
+#define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
+  ({ __typeof (oldval) _xchg_result, tmp;				      \
+     __asm__ ("\n"							      \
+	      "0:\tldr\t%1,[%2]\n\t"					      \
+	      "cmp\t%1,%4\n\t"						      \
+	      "movne\t%0,%1\n\t"					      \
+	      "bne\t1f\n\t"						      \
+	      "swpb\t%0,%3,[%2]\n\t"					      \
+	      "cmp\t%1,%0\n\t"						      \
+	      "swpbne\t%1,%0,[%2]\n\t"					      \
+	      "bne\t0b\n\t"						      \
+	      "1:"							      \
+	      : "=&r" (_xchg_result), "=&r" (tmp)			      \
+	      : "r" (mem), "r" (newval), "r" (oldval)			      \
+	      : "cc", "memory");					      \
+     _xchg_result; })
+
+
+#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
+  ({ __arm_link_error (); oldval; })
+
+#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
+  ({ __typeof (oldval) _xchg_result, tmp;				      \
+     __asm__ ("\n"							      \
+	      "0:\tldr\t%1,[%2]\n\t"					      \
+	      "cmp\t%1,%4\n\t"						      \
+	      "movne\t%0,%1\n\t"					      \
+	      "bne\t1f\n\t"						      \
+	      "swp\t%0,%3,[%2]\n\t"					      \
+	      "cmp\t%1,%0\n\t"						      \
+	      "swpne\t%1,%0,[%2]\n\t"					      \
+	      "bne\t0b\n\t"						      \
+	      "1:"							      \
+	      : "=&r" (_xchg_result), "=&r" (tmp)			      \
+	      : "r" (mem), "r" (newval), "r" (oldval)			      \
+	      : "cc", "memory");					      \
+     _xchg_result; })
+
+#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+  ({ __arm_link_error (); oldval; })
+
+#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) 	      \
+  __atomic_val_bysize (__arch_compare_and_exchange_val,acq,		      \
+		       mem, newval, oldval)
+
+#define atomic_compare_and_exchange_val_rel(mem, newval, oldval)	      \
+  __atomic_val_bysize (__arch_compare_and_exchange_val,acq,		      \
+		       mem, newval, oldval)
diff --git a/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/arm/bits/atomic.h b/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/arm/bits/atomic.h
deleted file mode 100644
index 8f63e25..0000000
--- a/uClibc/libpthread/nptl/sysdeps/unix/sysv/linux/arm/bits/atomic.h
+++ /dev/null
@@ -1,122 +0,0 @@
-/* Copyright (C) 2002, 2003, 2004, 2005 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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-#include <stdint.h>
-#include <sysdep.h>
-
-
-typedef int8_t atomic8_t;
-typedef uint8_t uatomic8_t;
-typedef int_fast8_t atomic_fast8_t;
-typedef uint_fast8_t uatomic_fast8_t;
-
-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;
-
-void __arm_link_error (void);
-
-#ifdef __thumb2__
-#define atomic_full_barrier() \
-     __asm__ __volatile__						      \
-	     ("movw\tip, #0x0fa0\n\t"					      \
-	      "movt\tip, #0xffff\n\t"					      \
-	      "blx\tip"							      \
-	      : : : "ip", "lr", "cc", "memory");
-#else
-#define atomic_full_barrier() \
-     __asm__ __volatile__						      \
-	     ("mov\tip, #0xffff0fff\n\t"				      \
-	      "mov\tlr, pc\n\t"						      \
-	      "add\tpc, ip, #(0xffff0fa0 - 0xffff0fff)"			      \
-	      : : : "ip", "lr", "cc", "memory");
-#endif
-
-/* Atomic compare and exchange.  This sequence relies on the kernel to
-   provide a compare and exchange operation which is atomic on the
-   current architecture, either via cleverness on pre-ARMv6 or via
-   ldrex / strex on ARMv6.  */
-
-#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) \
-  ({ __arm_link_error (); oldval; })
-
-/* It doesn't matter what register is used for a_oldval2, but we must
-   specify one to work around GCC PR rtl-optimization/21223.  Otherwise
-   it may cause a_oldval or a_tmp to be moved to a different register.  */
-
-#ifdef __thumb2__
-/* Thumb-2 has ldrex/strex.  However it does not have barrier instructions,
-   so we still need to use the kernel helper.  */
-#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
-  ({ register __typeof (oldval) a_oldval __asm__ ("r0");			      \
-     register __typeof (oldval) a_newval __asm__ ("r1") = (newval);		      \
-     register __typeof (mem) a_ptr __asm__ ("r2") = (mem);			      \
-     register __typeof (oldval) a_tmp __asm__ ("r3");			      \
-     register __typeof (oldval) a_oldval2 __asm__ ("r4") = (oldval);	      \
-     __asm__ __volatile__						      \
-	     ("0:\tldr\t%[tmp],[%[ptr]]\n\t"				      \
-	      "cmp\t%[tmp], %[old2]\n\t"				      \
-	      "bne\t1f\n\t"						      \
-	      "mov\t%[old], %[old2]\n\t"				      \
-	      "movw\t%[tmp], #0x0fc0\n\t"				      \
-	      "movt\t%[tmp], #0xffff\n\t"				      \
-	      "blx\t%[tmp]\n\t"						      \
-	      "bcc\t0b\n\t"						      \
-	      "mov\t%[tmp], %[old2]\n\t"				      \
-	      "1:"							      \
-	      : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp)		      \
-	      : [new] "r" (a_newval), [ptr] "r" (a_ptr),		      \
-		[old2] "r" (a_oldval2)					      \
-	      : "ip", "lr", "cc", "memory");				      \
-     a_tmp; })
-#else
-#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
-  ({ register __typeof (oldval) a_oldval __asm__ ("r0");			      \
-     register __typeof (oldval) a_newval __asm__ ("r1") = (newval);		      \
-     register __typeof (mem) a_ptr __asm__ ("r2") = (mem);			      \
-     register __typeof (oldval) a_tmp __asm__ ("r3");			      \
-     register __typeof (oldval) a_oldval2 __asm__ ("r4") = (oldval);	      \
-     __asm__ __volatile__						      \
-	     ("0:\tldr\t%[tmp],[%[ptr]]\n\t"				      \
-	      "cmp\t%[tmp], %[old2]\n\t"				      \
-	      "bne\t1f\n\t"						      \
-	      "mov\t%[old], %[old2]\n\t"				      \
-	      "mov\t%[tmp], #0xffff0fff\n\t"				      \
-	      "mov\tlr, pc\n\t"						      \
-	      "add\tpc, %[tmp], #(0xffff0fc0 - 0xffff0fff)\n\t"		      \
-	      "bcc\t0b\n\t"						      \
-	      "mov\t%[tmp], %[old2]\n\t"				      \
-	      "1:"							      \
-	      : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp)		      \
-	      : [new] "r" (a_newval), [ptr] "r" (a_ptr),		      \
-		[old2] "r" (a_oldval2)					      \
-	      : "ip", "lr", "cc", "memory");				      \
-     a_tmp; })
-#endif
-
-#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
-  ({ __arm_link_error (); oldval; })
-- 
1.5.5.6

