Add getcontext, setcontext, and swapcontext as system calls.

Previously these were libc functions but were requested to
be made into system calls for atomicity and to coalesce what
might be two entrances into the kernel (signal mask setting
and floating point trap) into one.

A few style nits and comments from bde are also included.

Tested on alpha by: gallatin

1 files changed, 14 insertions, 0 deletions

diff --git a/sys/sparc64/sparc64/machdep.c b/sys/sparc64/sparc64/machdep.c
index 116741b..84cf92a 100644
--- a/sys/sparc64/sparc64/machdep.c
+++ b/sys/sparc64/sparc64/machdep.c
@@ -504,6 +504,20 @@ freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
 }
 #endif
 
+int
+get_mcontext(struct thread *td, mcontext_t *mcp)
+{
+
+	return (ENOSYS);
+}
+
+int
+set_mcontext(struct thread *td, const mcontext_t *mcp)
+{
+
+	return (ENOSYS);
+}
+
 /*
  * Exit the kernel and execute a firmware call that will not return, as
  * specified by the arguments.