[OE-core] [PATCH 1/1] glibc: Allow 64 bit atomics for x86

[Juro Bystricky]

This patch fixes [YOCTO#8140].

The fix consist of allowing 64bit atomic ops for x86.
This should be safe for i586 and newer CPUs.
It also makes the synchronization more efficient.

Signed-off-by: Juro Bystricky <juro.bystricky at intel.com>
---
 .../glibc/glibc/use_64bit_atomics.patch            | 24 ++++++++++++++++++++++
 meta/recipes-core/glibc/glibc_2.22.bb              |  1 +
 2 files changed, 25 insertions(+)
 create mode 100644 meta/recipes-core/glibc/glibc/use_64bit_atomics.patch

diff --git a/meta/recipes-core/glibc/glibc/use_64bit_atomics.patch b/meta/recipes-core/glibc/glibc/use_64bit_atomics.patch
new file mode 100644
index 0000000..eb7f2b2
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/use_64bit_atomics.patch
@@ -0,0 +1,24 @@
+This patch alows using 64 bit atomic instructions on a
+32 bit platform. This is safe, providing x86 is Pentium or
+later (would not work on i386, i486). Using 64 bit atomic 
+instructions bypasses code containing a bug as documented in
+https://bugzilla.yoctoproject.org/show_bug.cgi?id=8140
+
+Upstream-Status: TBD
+
+Signed-off-by: Juro Bystricky <juro.bystricky at intel.com>
+
+
+Index: libc/sysdeps/i386/i486/bits/atomic.h
+===================================================================
+--- libc.orig/sysdeps/i386/i486/bits/atomic.h
++++ libc/sysdeps/i386/i486/bits/atomic.h
+@@ -54,7 +54,7 @@ typedef uintmax_t uatomic_max_t;
+ # endif
+ #endif
+ 
+-#define __HAVE_64B_ATOMICS 0
++#define __HAVE_64B_ATOMICS 1
+ #define USE_ATOMIC_COMPILER_BUILTINS 0
+ 
+ 
diff --git a/meta/recipes-core/glibc/glibc_2.22.bb b/meta/recipes-core/glibc/glibc_2.22.bb
index 020e417..2494ad7 100644
--- a/meta/recipes-core/glibc/glibc_2.22.bb
+++ b/meta/recipes-core/glibc/glibc_2.22.bb
@@ -50,6 +50,7 @@ SRC_URI_append_class-nativesdk = "\
            file://0001-nativesdk-glibc-Look-for-host-system-ld.so.cache-as-.patch \
            file://0002-nativesdk-glibc-Fix-buffer-overrun-with-a-relocated-.patch \
            file://0003-nativesdk-glibc-Raise-the-size-of-arrays-containing-.patch \
+           file://use_64bit_atomics.patch \
 "
 
 S = "${WORKDIR}/git"
-- 
1.9.1