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authorJeff Dike <jdike@addtoit.com>2006-09-25 23:33:04 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:49:07 -0700
commit4b84c69b5f6c08a540e3683f1360a6cdef2806c7 (patch)
tree708f1e4cbc2771886aaeb8eadb3ae4d458bc8133 /arch/um/os-Linux/sys-x86_64
parent19bdf0409f25a85a45874a5a8da6f3e4edcf4a49 (diff)
[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>
Diffstat (limited to 'arch/um/os-Linux/sys-x86_64')
-rw-r--r--arch/um/os-Linux/sys-x86_64/Makefile2
-rw-r--r--arch/um/os-Linux/sys-x86_64/signal.c16
2 files changed, 17 insertions, 1 deletions
diff --git a/arch/um/os-Linux/sys-x86_64/Makefile b/arch/um/os-Linux/sys-x86_64/Makefile
index 340ef26f594..f67842a7735 100644
--- a/arch/um/os-Linux/sys-x86_64/Makefile
+++ b/arch/um/os-Linux/sys-x86_64/Makefile
@@ -3,7 +3,7 @@
# Licensed under the GPL
#
-obj-$(CONFIG_MODE_SKAS) = registers.o
+obj-$(CONFIG_MODE_SKAS) = registers.o signal.o
USER_OBJS := $(obj-y)
diff --git a/arch/um/os-Linux/sys-x86_64/signal.c b/arch/um/os-Linux/sys-x86_64/signal.c
new file mode 100644
index 00000000000..3f369e5f976
--- /dev/null
+++ b/arch/um/os-Linux/sys-x86_64/signal.c
@@ -0,0 +1,16 @@
+/*
+ * 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 ucontext *uc;
+ asm("movq %%rdx, %0" : "=r" (uc));
+
+ (*handlers[sig])(sig, (struct sigcontext *) &uc->uc_mcontext);
+}