python-cryptography: bump to version 1.7.2
[buildroot-gz.git] / package / libunwind / 0002-Add-AO_REQUIRE_CAS-to-fix-build-on-ARM-v6.patch
blob2a37ed7784e881306a41ef90c9a74e10f4b3164d
1 From 24484e80b3e329c9edee1995e102f8612eedb79c Mon Sep 17 00:00:00 2001
2 From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
3 Date: Tue, 13 May 2014 23:32:27 +0200
4 Subject: [PATCH] Add AO_REQUIRE_CAS to fix build on ARM < v6
6 ARM earlier than ARMv6, such as ARMv4 and ARMv5 do not provide
7 optimize atomic operations in libatomic_ops. Since libunwind is using
8 such operations, it should define AO_REQUIRE_CAS before including
9 <atomic_ops.h> so that libatomic_ops knows it should use emulated
10 atomic operations instead (even though they are obviously a lot more
11 expensive).
13 Also, while real atomic operations are all inline functions and
14 therefore linking against libatomic_ops was not required, the emulated
15 atomic operations actually require linking against libatomic_ops, so
16 the commented AC_CHECK_LIB test in acinclude.m4 is uncommented to make
17 sure we link against libatomic_ops.
19 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
20 ---
21 acinclude.m4 | 8 +-------
22 include/libunwind_i.h | 1 +
23 2 files changed, 2 insertions(+), 7 deletions(-)
25 diff --git a/acinclude.m4 b/acinclude.m4
26 index 497f7c2..9c15af1 100644
27 --- a/acinclude.m4
28 +++ b/acinclude.m4
29 @@ -22,11 +22,5 @@ fi])
30 AC_DEFUN([CHECK_ATOMIC_OPS],
31 [dnl Check whether the system has the atomic_ops package installed.
32 AC_CHECK_HEADERS(atomic_ops.h)
34 -# Don't link against libatomic_ops for now. We don't want libunwind
35 -# to depend on libatomic_ops.so. Fortunately, none of the platforms
36 -# we care about so far need libatomic_ops.a (everything is done via
37 -# inline macros).
39 -# AC_CHECK_LIB(atomic_ops, main)
40 + AC_CHECK_LIB(atomic_ops, main)
42 diff --git a/include/libunwind_i.h b/include/libunwind_i.h
43 index 23f615e..deabdfd 100644
44 --- a/include/libunwind_i.h
45 +++ b/include/libunwind_i.h
46 @@ -95,6 +95,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
47 (pthread_mutex_unlock != NULL ? pthread_mutex_unlock (l) : 0)
49 #ifdef HAVE_ATOMIC_OPS_H
50 +# define AO_REQUIRE_CAS
51 # include <atomic_ops.h>
52 static inline int
53 cmpxchg_ptr (void *addr, void *old, void *new)
54 --
55 1.9.2