Break out stack(9) from ddb(4):

- Introduce per-architecture stack_machdep.c to hold stack_save(9).
- Introduce per-architecture machine/stack.h to capture any common
  definitions required between db_trace.c and stack_machdep.c.
- Add new kernel option "options STACK"; we will build in stack(9) if it is
  defined, or also if "options DDB" is defined to provide compatibility
  with existing users of stack(9).

Add new stack_save_td(9) function, which allows the capture of a stacktrace
of another thread rather than the current thread, which the existing
stack_save(9) was limited to.  It requires that the thread be neither
swapped out nor running, which is the responsibility of the consumer to
enforce.

Update stack(9) man page.

Build tested:	amd64, arm, i386, ia64, powerpc, sparc64, sun4v
Runtime tested:	amd64 (rwatson), arm (cognet), i386 (rwatson)

4 files changed, 135 insertions, 38 deletions

diff --git a/sys/powerpc/conf/GENERIC b/sys/powerpc/conf/GENERIC
index ef31949..7f1cc40 100644
--- a/sys/powerpc/conf/GENERIC
+++ b/sys/powerpc/conf/GENERIC
@@ -55,6 +55,7 @@ options 	COMPAT_FREEBSD5		#Compatible with FreeBSD5
 options 	COMPAT_FREEBSD6		#Compatible with FreeBSD6
 options 	SCSI_DELAY=5000		#Delay (in ms) before probing SCSI 
 options 	KTRACE			#ktrace(1) syscall trace support
+options 	STACK			#stack(9) support
 options 	SYSVSHM			#SYSV-style shared memory
 options 	SYSVMSG			#SYSV-style message queues
 options 	SYSVSEM			#SYSV-style semaphores
diff --git a/sys/powerpc/include/stack.h b/sys/powerpc/include/stack.h
new file mode 100644
index 0000000..c433a9f
--- /dev/null
+++ b/sys/powerpc/include/stack.h
@@ -0,0 +1,36 @@
+/*-
+ * Mach Operating System
+ * Copyright (c) 1992 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _MACHINE_STACK_H_
+#define	_MACHINE_STACK_H_
+
+extern int trapexit[];
+extern int asttrapexit[];
+extern int end[];
+
+#endif /* !_MACHINE_STACK_H_ */
diff --git a/sys/powerpc/powerpc/db_trace.c b/sys/powerpc/powerpc/db_trace.c
index 188e028..3fdfc76 100644
--- a/sys/powerpc/powerpc/db_trace.c
+++ b/sys/powerpc/powerpc/db_trace.c
@@ -41,6 +41,7 @@
 #include <machine/db_machdep.h>
 #include <machine/pcb.h>
 #include <machine/spr.h>
+#include <machine/stack.h>
 #include <machine/trap.h>
 
 #include <ddb/ddb.h>
@@ -96,10 +97,6 @@ struct db_variable db_regs[] = {
 };
 struct db_variable *db_eregs = db_regs + sizeof (db_regs)/sizeof (db_regs[0]);
 
-extern int trapexit[];
-extern int asttrapexit[];
-extern int end[];
-
 /*
  * register variable handling
  */
@@ -287,37 +284,3 @@ db_trace_thread(struct thread *td, int count)
 	ctx = kdb_thr_ctx(td);
 	return (db_backtrace(td, (db_addr_t)ctx->pcb_sp, count));
 }
-
-void
-stack_save(struct stack *st)
-{
-	vm_offset_t callpc;
-	db_addr_t stackframe;
-
-	stack_zero(st);
-	stackframe = (db_addr_t)__builtin_frame_address(1);
-	if (stackframe < PAGE_SIZE)
-		return;
-	while (1) {
-		stackframe = *(db_addr_t *)stackframe;
-		if (stackframe < PAGE_SIZE)
-			break;
-		callpc = *(vm_offset_t *)(stackframe + 4) - 4;
-		if ((callpc & 3) || (callpc < 0x100))
-			break;
-
-		/*
-		 * Don't bother traversing trap-frames - there should
-		 * be enough info down to the frame to work out where
-		 * things are going wrong. Plus, prevents this shortened
-		 * version of code from accessing user-space frames
-		 */
-		if (callpc + 4 == (db_addr_t) &trapexit ||
-		    callpc + 4 == (db_addr_t) &asttrapexit)
-			break;
-
-		if (stack_put(st, callpc) == -1)
-			break;
-	}
-}
-
diff --git a/sys/powerpc/powerpc/stack_machdep.c b/sys/powerpc/powerpc/stack_machdep.c
new file mode 100644
index 0000000..7bc6fd4
--- /dev/null
+++ b/sys/powerpc/powerpc/stack_machdep.c
@@ -0,0 +1,97 @@
+/*-
+ * Copyright (c) 2005 Antoine Brodin
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/stack.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_extern.h>
+
+#include <machine/db_machdep.h>
+#include <machine/pcb.h>
+#include <machine/spr.h>
+#include <machine/stack.h>
+#include <machine/trap.h>
+
+static void
+stack_capture(struct stack *st, register_t frame)
+{
+	vm_offset_t callpc;
+
+	stack_zero(st);
+	if (frame < PAGE_SIZE)
+		return;
+	while (1) {
+		frame = *(register_t *)frame;
+		if (frame < PAGE_SIZE)
+			break;
+		callpc = *(vm_offset_t *)(frame + 4) - 4;
+		if ((callpc & 3) || (callpc < 0x100))
+			break;
+
+		/*
+		 * Don't bother traversing trap-frames - there should
+		 * be enough info down to the frame to work out where
+		 * things are going wrong. Plus, prevents this shortened
+		 * version of code from accessing user-space frames
+		 */
+		if (callpc + 4 == (register_t) &trapexit ||
+		    callpc + 4 == (register_t) &asttrapexit)
+			break;
+
+		if (stack_put(st, callpc) == -1)
+			break;
+	}
+}
+
+void
+stack_save_td(struct stack *st, struct thread *td)
+{
+	register_t frame;
+
+	if (TD_IS_SWAPPED(td))
+		panic("stack_save_td: swapped");
+	if (TD_IS_RUNNING(td))
+		panic("stack_save_td: running");
+
+	frame = td->td_pcb->pcb_sp;
+	stack_capture(st, frame);
+}
+
+void
+stack_save(struct stack *st)
+{
+	register_t frame;
+
+	frame = (register_t)__builtin_frame_address(1);
+	stack_capture(st, frame);
+}