Let fork1, uvm_fork, and cpu_fork take a function/argument pair as argument,

instead of doing fork1, cpu_set_kpc. This lets us retire cpu_set_kpc and
avoid a multiprocessor race.

This commit breaks vax because it doesn't look like any other arch, someone
working on vax might want to look at this and try to adapt the code to be
more like the rest of the world.

Idea and uvm parts from NetBSD.

1 files changed, 31 insertions, 1 deletions

diff --git a/sys/arch/m68k/m68k/m68k_machdep.c b/sys/arch/m68k/m68k/m68k_machdep.c
index 4b0c39194b8..287d064859f 100644
--- a/sys/arch/m68k/m68k/m68k_machdep.c
+++ b/sys/arch/m68k/m68k/m68k_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: m68k_machdep.c,v 1.1 1997/07/06 07:46:28 downsj Exp $	*/
+/*	$OpenBSD: m68k_machdep.c,v 1.2 2001/11/06 18:41:09 art Exp $	*/
 /*	$NetBSD: m68k_machdep.c,v 1.3 1997/06/12 09:57:04 veego Exp $	*/
 
 /*-
@@ -38,7 +38,37 @@
  */
 
 #include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/syscall.h>
+#include <sys/ktrace.h>
+
+#include <machine/frame.h>
+#include <machine/reg.h>
 
 /* the following is used externally (sysctl_hw) */
 char	machine_arch[] = MACHINE_ARCH;	/* from <machine/param.h> */
 
+void    userret __P((struct proc *, int, u_quad_t));	/* XXX */
+/*
+ * Process the tail end of a fork() for the child
+ *
+ * XXX - this is probably the wrong file.
+ */
+void
+child_return(arg)
+	void *arg;
+{
+	struct proc *p = (struct proc *)arg;
+	struct frame *f = (struct frame *)p->p_md.md_regs;
+
+	f->f_regs[D0] = 0;
+	f->f_sr &= ~PSL_C;	/* carry bit */
+	f->f_format = FMT0;
+
+	userret(p, f->f_pc, p->p_sticks);
+#ifdef KTRACE
+	if (KTRPOINT(p, KTR_SYSRET))
+		ktrsysret(p, SYS_fork, 0, 0);
+#endif
+}
+