aarch64: blacklist gcc prior to 5.1

[urcu.git] / README.md

diff --git a/README.md b/README.md
index 7a33cd7ea044c138618d886f50325661ff757105..8dfd5e96a62ab2cc048e54e26a111bcc7b357894 100644 (file)
--- a/README.md
+++ b/README.md
@@ -86,6 +86,8 @@ supported, with the following exceptions:
   - Alpha, ia64 and ARM architectures depend on GCC 4.x with atomic builtins
     support. For ARM this was introduced with GCC 4.4:
     http://gcc.gnu.org/gcc-4.4/changes.html.
+  - Linux aarch64 depends on GCC 5.1 or better because prior versions
+    perform unsafe access to deallocated stack.
 
 Clang version 3.0 (based on LLVM 3.0) is supported.
 
@@ -224,10 +226,11 @@ be overridden with `-DSIGRCU` by modifying `Makefile.build.inc`.
 
 The BP library flavor stands for "bulletproof". It is specifically
 designed to help tracing library to hook on applications without
-requiring to modify these applications. `urcu_bp_init()`,
-`urcu_bp_register_thread()` and `urcu_bp_unregister_thread()` all become
-nops. The state is dealt with by the library internally at the expense
-of read-side and write-side performance.
+requiring to modify these applications. `urcu_bp_init()`, and
+`urcu_bp_unregister_thread()` all become nops, whereas calling
+`urcu_bp_register_thread()` becomes optional. The state is dealt with by
+the library internally at the expense of read-side and write-side
+performance.
 
 
 ### Initialization
@@ -387,7 +390,7 @@ For always-on debugging self-checks:
        ./configure --enable-rcu-debug
 
 For fine grained enabling of debugging self-checks, build
-urserspace-rcu with DEBUG_RCU defined and compile dependent
+userspace-rcu with DEBUG_RCU defined and compile dependent
 applications with DEBUG_RCU defined when necessary.
 
 Warning: Enabling this feature result in a performance penalty.
@@ -410,6 +413,20 @@ systems can be disabled with:
 theoretically yielding slightly better performance.
 
 
+### Usage of `--enable-cds-lfht-iter-debug`
+
+By default the library is configured with extra debugging checks for
+lock-free hash table iterator traversal disabled.
+
+Building liburcu with --enable-cds-lfht-iter-debug and rebuilding
+application to match the ABI change allows finding cases where the hash
+table iterator is re-purposed to be used on a different hash table while
+still being used to iterate on a hash table.
+
+This option alters the rculfhash ABI. Make sure to compile both library
+and application with matching configuration.
+
+
 Make targets
 ------------