aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorGravatar Thomas Petazzoni <thomas.petazzoni@bootlin.com>2018-08-16 11:42:18 +0200
committerGravatar Thomas Petazzoni <thomas.petazzoni@bootlin.com>2018-08-16 11:42:50 +0200
commit6288409642d8368104f916bd264d2cb042942dfa (patch)
treea35f1c543a6ed6e75dec8b9e72fe4f8fd7e710bd
parentf45976b2c759b1630a2886e75312340b3b511f81 (diff)
downloadbuildroot-6288409642d8368104f916bd264d2cb042942dfa.tar.gz
buildroot-6288409642d8368104f916bd264d2cb042942dfa.tar.bz2
libselinux: add patch to fix build with gcc < 4.7
This commit adds a patch from Hollis Blanchard on libselinux to fix build on host machines that have gcc < 4.7. Fixes: http://autobuild.buildroot.net/results/a82bb0c0b22ff24263ad7a7d165b21c0df7b3b1d/ Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
-rw-r--r--package/libselinux/0004-Fix-build-break-around-__atomic_-with-GCC-4.7.patch.txt70
1 files changed, 70 insertions, 0 deletions
diff --git a/package/libselinux/0004-Fix-build-break-around-__atomic_-with-GCC-4.7.patch.txt b/package/libselinux/0004-Fix-build-break-around-__atomic_-with-GCC-4.7.patch.txt
new file mode 100644
index 0000000000..85bd064066
--- /dev/null
+++ b/package/libselinux/0004-Fix-build-break-around-__atomic_-with-GCC-4.7.patch.txt
@@ -0,0 +1,70 @@
+From abe76789f8e7ce61b357f693eaed5b28feab5ce2 Mon Sep 17 00:00:00 2001
+From: Hollis Blanchard <hollis_blanchard@mentor.com>
+Date: Mon, 13 Aug 2018 12:11:33 -0700
+Subject: [PATCH] Fix build break around __atomic_*() with GCC<4.7
+
+The __atomic_* GCC primitives were introduced in GCC 4.7, but Red Hat
+Enterprise Linux 6.x (for example) provides GCC 4.4. Tweak the current code to
+use the (most conservative) __sync_synchronize() primitive provided by those
+older GCC versions.
+
+(Really, no __atomic or __sync operations are needed here at all, since POSIX
+4.12 "Memory Synchronization" says pthread_mutex_lock() and
+pthread_mutex_unlock() "synchronize memory with respect to other threads"...)
+
+Signed-off-by: Hollis Blanchard <hollis_blanchard@mentor.com>
+---
+ libselinux/src/label_file.h | 18 ++++++++++++++++++
+ 1 file changed, 18 insertions(+)
+
+diff --git a/libselinux/src/label_file.h b/libselinux/src/label_file.h
+index 2fa85474..47859baf 100644
+--- a/libselinux/src/label_file.h
++++ b/libselinux/src/label_file.h
+@@ -351,8 +351,14 @@ static inline int compile_regex(struct saved_data *data, struct spec *spec,
+ * init_routine does not take a parameter, it's not possible
+ * to use, so we generate the same effect with atomics and a
+ * mutex */
++#ifdef __ATOMIC_RELAXED
+ regex_compiled =
+ __atomic_load_n(&spec->regex_compiled, __ATOMIC_ACQUIRE);
++#else
++ /* GCC <4.7 */
++ __sync_synchronize();
++ regex_compiled = spec->regex_compiled;
++#endif
+ if (regex_compiled) {
+ return 0; /* already done */
+ }
+@@ -360,8 +366,14 @@ static inline int compile_regex(struct saved_data *data, struct spec *spec,
+ __pthread_mutex_lock(&spec->regex_lock);
+ /* Check if another thread compiled the regex while we waited
+ * on the mutex */
++#ifdef __ATOMIC_RELAXED
+ regex_compiled =
+ __atomic_load_n(&spec->regex_compiled, __ATOMIC_ACQUIRE);
++#else
++ /* GCC <4.7 */
++ __sync_synchronize();
++ regex_compiled = spec->regex_compiled;
++#endif
+ if (regex_compiled) {
+ __pthread_mutex_unlock(&spec->regex_lock);
+ return 0;
+@@ -404,7 +416,13 @@ static inline int compile_regex(struct saved_data *data, struct spec *spec,
+ }
+
+ /* Done. */
++#ifdef __ATOMIC_RELAXED
+ __atomic_store_n(&spec->regex_compiled, true, __ATOMIC_RELEASE);
++#else
++ /* GCC <4.7 */
++ spec->regex_compiled = true;
++ __sync_synchronize();
++#endif
+ __pthread_mutex_unlock(&spec->regex_lock);
+ return 0;
+ }
+--
+2.13.0
+