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)

10 files changed, 16 insertions, 1 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 2f62598..eb66fa7 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -465,6 +465,13 @@ options 	REGRESSION
 #
 options 	COMPILING_LINT
 
+#
+# STACK enables the stack(9) facility, allowing the capture of kernel stack
+# for the purpose of procinfo(1), etc.  stack(9) will also be compiled in
+# automatically if DDB(4) is compiled into the kernel.
+#
+options 	STACK
+
 
 #####################################################################
 # PERFORMANCE MONITORING OPTIONS
diff --git a/sys/conf/files b/sys/conf/files
index ff4d8f2..a0a796d 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1504,7 +1504,7 @@ kern/subr_sbuf.c		standard
 kern/subr_scanf.c		standard
 kern/subr_sleepqueue.c		standard
 kern/subr_smp.c			standard
-kern/subr_stack.c		optional ddb
+kern/subr_stack.c		optional ddb | stack
 kern/subr_taskqueue.c		standard
 kern/subr_trap.c		standard
 kern/subr_turnstile.c		standard
diff --git a/sys/conf/files.amd64 b/sys/conf/files.amd64
index dbe920d..8276f85 100644
--- a/sys/conf/files.amd64
+++ b/sys/conf/files.amd64
@@ -119,6 +119,7 @@ amd64/amd64/nexus.c		standard
 amd64/amd64/pmap.c		standard	nowerror
 amd64/amd64/prof_machdep.c	optional	profiling-routine
 amd64/amd64/sigtramp.S		standard
+amd64/amd64/stack_machdep.c	optional	ddb | stack
 amd64/amd64/support.S		standard
 amd64/amd64/sys_machdep.c	standard
 amd64/amd64/trap.c		standard
diff --git a/sys/conf/files.arm b/sys/conf/files.arm
index 42eb602..3cb7a5c 100644
--- a/sys/conf/files.arm
+++ b/sys/conf/files.arm
@@ -34,6 +34,7 @@ arm/arm/nexus.c			standard
 arm/arm/pmap.c			standard
 arm/arm/setcpsr.S		standard
 arm/arm/setstack.s		standard
+arm/arm/stack_machdep.c		optional	ddb | stack
 arm/arm/support.S		standard
 arm/arm/swtch.S			standard
 arm/arm/sys_machdep.c		standard
diff --git a/sys/conf/files.i386 b/sys/conf/files.i386
index 1ddcb4c..9e43eca 100644
--- a/sys/conf/files.i386
+++ b/sys/conf/files.i386
@@ -308,6 +308,7 @@ i386/i386/nexus.c		standard
 i386/i386/perfmon.c		optional perfmon
 i386/i386/pmap.c		standard nowerror
 i386/i386/ptrace_machdep.c	standard
+i386/i386/stack_machdep.c	optional ddb | stack
 i386/i386/support.s		standard
 i386/i386/swtch.s		standard
 i386/i386/sys_machdep.c		standard
diff --git a/sys/conf/files.ia64 b/sys/conf/files.ia64
index f2f5b36..3824fe4 100644
--- a/sys/conf/files.ia64
+++ b/sys/conf/files.ia64
@@ -98,6 +98,7 @@ ia64/ia64/sapic.c		standard
 ia64/ia64/setjmp.S		standard
 ia64/ia64/ssc.c			optional	ski
 ia64/ia64/sscdisk.c		optional	ski
+ia64/ia64/stack_machdep.c	optional	ddb | stack
 ia64/ia64/support.S		standard
 ia64/ia64/sys_machdep.c		standard
 ia64/ia64/syscall.S		standard
diff --git a/sys/conf/files.powerpc b/sys/conf/files.powerpc
index fc72f32..3e85464 100644
--- a/sys/conf/files.powerpc
+++ b/sys/conf/files.powerpc
@@ -61,6 +61,7 @@ powerpc/powerpc/pmap_dispatch.c	standard
 powerpc/powerpc/sc_machdep.c	optional	sc
 powerpc/powerpc/setjmp.S	standard
 powerpc/powerpc/sigcode.S	standard
+powerpc/powerpc/stack_machdep.c	optional	ddb | stack
 powerpc/powerpc/suswintr.c	standard
 powerpc/powerpc/syncicache.c	standard
 powerpc/powerpc/sys_machdep.c	standard
diff --git a/sys/conf/files.sparc64 b/sys/conf/files.sparc64
index 5f29180..3a0f6f0 100644
--- a/sys/conf/files.sparc64
+++ b/sys/conf/files.sparc64
@@ -124,6 +124,7 @@ sparc64/sparc64/rtc.c		optional	rtc ebus | rtc isa
 sparc64/sparc64/rwindow.c	standard
 sparc64/sparc64/sc_machdep.c	optional	sc
 sparc64/sparc64/spitfire.c	standard
+sparc64/sparc64/stack_machdep.c	optional	ddb | stack
 sparc64/sparc64/support.S	standard
 sparc64/sparc64/sys_machdep.c	standard
 sparc64/sparc64/swtch.S		standard
diff --git a/sys/conf/files.sun4v b/sys/conf/files.sun4v
index 37dfc32..700ca8a 100644
--- a/sys/conf/files.sun4v
+++ b/sys/conf/files.sun4v
@@ -74,6 +74,7 @@ sparc64/sparc64/prof_machdep.c	optional	profiling-routine
 sparc64/sparc64/rwindow.c	standard
 sun4v/sun4v/rtc.c		standard
 sun4v/sun4v/simdisk.c		optional	simulator
+sun4v/sun4v/stack_machdep.c	optional	ddb | stack
 sun4v/sun4v/support.S		standard
 sparc64/sparc64/sys_machdep.c	standard
 sun4v/sun4v/swtch.S		standard
diff --git a/sys/conf/options b/sys/conf/options
index 143c0aa..3f9769a 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -140,6 +140,7 @@ SHOW_BUSYBUFS
 SLEEPQUEUE_PROFILING
 SLHCI_DEBUG	opt_slhci.h
 SPX_HACK
+STACK		opt_stack.h
 SUIDDIR
 MSGMNB		opt_sysvipc.h
 MSGMNI		opt_sysvipc.h