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

4 files changed, 9 insertions, 15 deletions

diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 181463e..1aedc3d 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2317,7 +2317,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
 /*
  * Get machine context.
  */
-void
+int
 get_mcontext(struct thread *td, mcontext_t *mcp)
 {
 	struct trapframe *tp;
@@ -2344,6 +2344,7 @@ get_mcontext(struct thread *td, mcontext_t *mcp)
 	mcp->mc_ss = tp->tf_ss;
 	mcp->mc_len = sizeof(*mcp);
 	get_fpcontext(td, mcp);
+	return (0);
 }
 
 /*
diff --git a/sys/i386/include/signal.h b/sys/i386/include/signal.h
index 29a9776..efc7ef0 100644
--- a/sys/i386/include/signal.h
+++ b/sys/i386/include/signal.h
@@ -119,7 +119,7 @@ struct sigcontext {
 	int	sc_efl;
 	int	sc_esp;
 	int	sc_ss;
-	int	sc_len;			/* sizeof(struct mcontext_t) */
+	int	sc_len;			/* sizeof(mcontext_t) */
 	/*
 	 * XXX - See <machine/ucontext.h> and <machine/npx.h> for
 	 *       the following fields.
@@ -127,7 +127,7 @@ struct sigcontext {
 	int	sc_fpformat;
 	int	sc_ownedfp;
 	int	sc_spare1[1];
-	int	sc_fpregs[128];
+	int	sc_fpstate[128];
 	int	sc_spare2[8];
 };
 
diff --git a/sys/i386/include/ucontext.h b/sys/i386/include/ucontext.h
index af9b4fd..ea6f0b6 100644
--- a/sys/i386/include/ucontext.h
+++ b/sys/i386/include/ucontext.h
@@ -38,7 +38,7 @@ typedef struct __mcontext {
 	 * and ucontext_t at the same time.
 	 */
 	int	mc_onstack;		/* XXX - sigcontext compat. */
-	int	mc_gs;
+	int	mc_gs;			/* machine state (trapframe) */
 	int	mc_fs;
 	int	mc_es;
 	int	mc_ds;
@@ -55,7 +55,7 @@ typedef struct __mcontext {
 	int	mc_eip;
 	int	mc_cs;
 	int	mc_eflags;
-	int	mc_esp;			/* machine state */
+	int	mc_esp;
 	int	mc_ss;
 
 	int	mc_len;			/* sizeof(mcontext_t) */
@@ -72,8 +72,7 @@ typedef struct __mcontext {
 	int	mc_spare2[8];
 } mcontext_t;
 
-#ifdef _KERNEL
-#ifdef COMPAT_FREEBSD4
+#if defined(_KERNEL) && defined(COMPAT_FREEBSD4)
 /* For 4.x binaries */
 struct mcontext4 {
 	int	mc_onstack;		/* XXX - sigcontext compat. */
@@ -101,10 +100,4 @@ struct mcontext4 {
 };
 #endif
 
-struct thread;
-
-void	get_mcontext(struct thread *td, mcontext_t *mcp);
-int	set_mcontext(struct thread *td, const mcontext_t *mcp);
-#endif
-
 #endif /* !_MACHINE_UCONTEXT_H_ */
diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c
index 3395c99..661a698 100644
--- a/sys/i386/isa/npx.c
+++ b/sys/i386/isa/npx.c
@@ -161,14 +161,14 @@ void	stop_emulating(void);
 
 typedef u_char bool_t;
 
+static	void	fpusave(union savefpu *);
+static	void	fpurstor(union savefpu *);
 static	int	npx_attach(device_t dev);
 static	void	npx_identify(driver_t *driver, device_t parent);
 #ifndef SMP
 static	void	npx_intr(void *);
 #endif
 static	int	npx_probe(device_t dev);
-static	void	fpusave(union savefpu *);
-static	void	fpurstor(union savefpu *);
 #ifdef I586_CPU_XXX
 static	long	timezero(const char *funcname,
 		    void (*func)(void *buf, size_t len));