X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=README;h=659511f7c46eba7260e1297ae247efceaa88b7bf;hp=a2ca1eb147a7318845ac0da336ff40ba5ba86f22;hb=ef84facf4b0c23bd695ca9300055e3ffc9b56006;hpb=955f5e52a3b7b6bdb80264279b990486e990dd02

diff --git a/README b/README
index a2ca1eb..659511f 100644
--- a/README
+++ b/README
@@ -24,9 +24,23 @@ BUILDING
 ARCHITECTURES SUPPORTED
 -----------------------
 
-Currently, x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64, S390, S390x
-and Sparcv9 32/64 are supported. Only tested on Linux so far, but should
-theoretically work on other operating systems.
+Currently, x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64, S390, S390x,
+ARM, Alpha, ia64 and Sparcv9 32/64 are supported. Only tested on Linux so
+far, but should theoretically work on other operating systems.
+
+ARM depends on running a Linux kernel 2.6.15 or better.
+
+The gcc compiler versions 3.3, 3.4, 4.0, 4.1, 4.2, 4.3, 4.4 and 4.5 are
+supported, with the following exceptions:
+
+- gcc 3.3 and 3.4 have a bug that prevents them from generating volatile
+  accesses to offsets in a TLS structure on 32-bit x86. These versions are
+  therefore not compatible with liburcu on x86 32-bit (i386, i486, i586, i686).
+  The problem has been reported to the gcc community:
+    http://www.mail-archive.com/gcc-bugs@gcc.gnu.org/msg281255.html
+- Alpha, ia64 and ARM architectures depend on 4.x gcc with atomic builtins
+  support.
+
 
 QUICK START GUIDE
 -----------------
@@ -71,7 +85,8 @@ Usage of liburcu-mb
 
 Usage of liburcu-signal
 
-	* #include <urcu-signal.h>
+	* #include <urcu.h>
+	* Compile any _LGPL_SOURCE code using this library with "-DRCU_SIGNAL".
 	* Link the application with "-lurcu-signal".
 	* Version of the library that requires a signal, typically SIGUSR1. Can
 	  be overridden with -DSIGRCU by modifying Makefile.build.inc.
@@ -175,3 +190,24 @@ SMP support
 		./configure --disable-smp-support
 
 	theoretically yielding slightly better performance.
+
+Interaction with fork()
+
+	Special care must be taken for applications performing fork() without
+	any following exec(). This is caused by the fact that Linux only clones
+	the thread calling fork(), and thus never replicates any of the other
+	parent thread into the child process. Most liburcu implementations
+	require that all registrations (as reader, defer_rcu and call_rcu
+	threads) should be released before a fork() is performed, except for the
+	rather common scenario where fork() is immediately followed by exec() in
+	the child process. The only implementation not subject to that rule is
+	liburcu-bp, which is designed to handle fork() by calling
+	rcu_bp_before_fork, rcu_bp_after_fork_parent and
+	rcu_bp_after_fork_child.
+
+	Applications that use call_rcu() and that fork() without
+	doing an immediate exec() must take special action.  The parent
+	must invoke call_rcu_before_fork() before the fork() and
+	call_rcu_after_fork_parent() after the fork().  The child
+	process must invoke call_rcu_after_fork_child().
+	These three APIs are suitable for passing to pthread_atfork().