From 4b84c69b5f6c08a540e3683f1360a6cdef2806c7 Mon Sep 17 00:00:00 2001
From: Jeff Dike <jdike@addtoit.com>
Date: Mon, 25 Sep 2006 23:33:04 -0700
Subject: [PATCH] uml: Move signal handlers to arch code
Have most signals go through an arch-provided handler which recovers the
sigcontext and then calls a generic handler. This replaces the
ARCH_GET_SIGCONTEXT macro, which was somewhat fragile. On x86_64, recovering
%rdx (which holds the sigcontext pointer) must be the first thing that
happens. sig_handler duly invokes that first, but there is no guarantee that
I can see that instructions won't be reordered such that %rdx is used before
that. Having the arch provide the handler seems much more robust.
Some signals in some parts of UML require their own handlers - these places
don't call set_handler any more. They call sigaction or signal themselves.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
arch/um/os-Linux/sys-i386/Makefile | 2 +-
arch/um/os-Linux/sys-i386/signal.c | 15 +++++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
create mode 100644 arch/um/os-Linux/sys-i386/signal.c
(limited to 'arch/um/os-Linux/sys-i386')
diff --git a/arch/um/os-Linux/sys-i386/Makefile b/arch/um/os-Linux/sys-i386/Makefile
index b3213613c41..37806621b25 100644
--- a/arch/um/os-Linux/sys-i386/Makefile
+++ b/arch/um/os-Linux/sys-i386/Makefile
@@ -3,7 +3,7 @@
# Licensed under the GPL
#
-obj-$(CONFIG_MODE_SKAS) = registers.o tls.o
+obj-$(CONFIG_MODE_SKAS) = registers.o signal.o tls.o
USER_OBJS := $(obj-y)
diff --git a/arch/um/os-Linux/sys-i386/signal.c b/arch/um/os-Linux/sys-i386/signal.c
new file mode 100644
index 00000000000..0d3eae51835
--- /dev/null
+++ b/arch/um/os-Linux/sys-i386/signal.c
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL
+ */
+
+#include <signal.h>
+
+extern void (*handlers[])(int sig, struct sigcontext *sc);
+
+void hard_handler(int sig)
+{
+ struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
+
+ (*handlers[sig])(sig, sc);
+}
--
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