ARC port to uClibc

For this port, I would like to give due credit to:

- Folks from Codito technologies (Sameer, Amit, Kanika, Ramana,...)
   who did the very first port

- ARC UK from 2007-2009 (Joern, Irfan, Khurram, Phil...

- Late Brendan Kehoe (may he RIP)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/arc/sigaction.c b/libc/sysdeps/linux/arc/sigaction.c
new file mode 100644
index 000000000..a4bc5f34b
--- /dev/null
+++ b/libc/sysdeps/linux/arc/sigaction.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <bits/kernel_sigaction.h>
+
+extern void __default_rt_sa_restorer(void);
+//libc_hidden_proto(__default_rt_sa_restorer);
+
+#define SA_RESTORER	0x04000000
+
+/* If @act is not NULL, change the action for @sig to @act.
+   If @oact is not NULL, put the old action for @sig in @oact.  */
+int
+__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
+{
+	struct sigaction kact;
+
+	/* !act means caller only wants to know @oact
+	 * Hence only otherwise, do SA_RESTORER stuff
+	 *
+	 * For the normal/default cases (user not providing SA_RESTORER) use
+	 * a real sigreturn stub to avoid kernel synthesizing one on user stack
+	 * at runtime, which needs PTE permissions update (hence TLB entry
+	 * update) and costly cache line flushes for code modification
+	 */
+	if (act && !(act->sa_flags & SA_RESTORER)) {
+		memcpy(&kact, act, sizeof(kact));
+		kact.sa_restorer = __default_rt_sa_restorer;
+		kact.sa_flags |= SA_RESTORER;
+
+		act = &kact;
+	}
+
+	return __syscall_rt_sigaction(sig, act, oact, sizeof(act->sa_mask));
+}
+
+#ifndef LIBC_SIGACTION
+weak_alias(__libc_sigaction,sigaction)
+libc_hidden_weak(sigaction)
+#endif