--- /usr/src/sys/amd64/include/asm.h	2007-12-30 13:49:11.000000000 +0000
+++ src/sys/amd64/include/asm.h	2007-12-30 22:09:37.000000000 +0000
@@ -83,7 +83,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)					\
+	.section	set_srcid,"a",@progbits;	\
+	.p2align	0;				\
+	.asciz		#s;				\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/arm/include/asm.h	2007-12-30 13:49:12.000000000 +0000
+++ src/sys/arm/include/asm.h	2008-01-03 01:19:27.000000000 +0000
@@ -104,7 +104,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)     .ident s
+#define __FBSDID(s)						\
+	.section	"set_srcid","a",%progbits;		\
+	.p2align	0;					\
+	.asciz		#s;					\
+	.previous
 #else
 #define __FBSDID(s)     /* nothing */
 #endif
--- /usr/src/sys/i386/include/asm.h	2007-12-30 13:54:25.000000000 +0000
+++ src/sys/i386/include/asm.h	2007-12-30 22:09:38.000000000 +0000
@@ -93,7 +93,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)					\
+	.section	set_srcid,"a",@progbits;	\
+	.p2align	0;				\
+	.asciz		#s;				\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/ia64/include/asm.h	2007-12-30 13:54:27.000000000 +0000
+++ src/sys/ia64/include/asm.h	2007-12-30 22:09:38.000000000 +0000
@@ -182,7 +182,11 @@
  * ID tag macros
  */
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)						\
+	.section	set_srcid,"a",@progbits;		\
+	.p2align	0;					\
+	.asciz		#s;					\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/powerpc/include/asm.h	2007-12-30 13:54:39.000000000 +0000
+++ src/sys/powerpc/include/asm.h	2007-12-30 22:09:42.000000000 +0000
@@ -79,7 +79,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)					\
+	.section	set_srcid,"a",@progbits;	\
+	.p2align	0;				\
+	.asciz		#s;				\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/sparc64/include/asm.h	2007-12-30 13:54:40.000000000 +0000
+++ src/sys/sparc64/include/asm.h	2007-12-30 22:09:42.000000000 +0000
@@ -101,7 +101,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)						\
+	.section	set_srcid,"a",@progbits;		\
+	.p2align	0;					\
+	.asciz		#s;					\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/sun4v/include/asm.h	2007-12-30 13:54:41.000000000 +0000
+++ src/sys/sun4v/include/asm.h	2007-12-30 22:09:42.000000000 +0000
@@ -108,7 +108,11 @@
 
 #undef __FBSDID
 #if !defined(lint) && !defined(STRIP_FBSDID)
-#define __FBSDID(s)	.ident s
+#define __FBSDID(s)						\
+	.section	set_srcid,"a",@progbits;		\
+	.p2align	0;					\
+	.asciz		#s;					\
+	.previous
 #else
 #define __FBSDID(s)	/* nothing */
 #endif /* not lint and not STRIP_FBSDID */
--- /usr/src/sys/sys/cdefs.h	2007-12-30 13:54:41.000000000 +0000
+++ src/sys/sys/cdefs.h	2008-01-05 02:40:48.000000000 +0000
@@ -402,11 +402,52 @@
  *	__FBSDID("$FreeBSD: src/sys/sys/cdefs.h,v 1.94 2007/12/09 21:00:36 alc Exp $");
  */
 #ifndef	__FBSDID
-#if !defined(lint) && !defined(STRIP_FBSDID)
+#if defined(lint) || defined(STRIP_FBSDID)
+#define	__FBSDID(s)	struct __hack
+#else
+/*
+ * We want to have tags embedded. We let the user choose between the
+ * behaviour he wants to have.  This can still be old, bare and boring
+ * FBSDID... Note that you won't get kern.srcids handling that way.
+ */
+#if defined(OLD_FBSDID)
 #define	__FBSDID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
 #else
-#define	__FBSDID(s)	struct __hack
+/*
+ * Smart user however prefers fully featured, brand new one FBSDID.
+ * This is the right choice to get kern.srcids working. DDB command
+ * "show srcids" included as well.
+ *
+ * ARM is a bit special.
+ */
+#ifdef __arm__
+#define	FBSDID_SECTYPE	"%progbits"
+#else
+#define	FBSDID_SECTYPE	"@progbits"
+#endif
+
+/*
+ * i386, amd64 and ia64 are special too--instead of: .section "name",
+ * they want: .section name
+ */
+#if defined(__i386__) || defined(__amd64__) || defined(__ia64__)
+#define	FBSDID_SECTION()						\
+	__asm__(".section set_srcid,\"a\"," FBSDID_SECTYPE)
+#else /* expect __sparc64__, __arm__, __powerpc__ and __sun4v */
+#define	FBSDID_SECTION()						\
+	__asm__(".section \"set_srcid\",\"a\"," FBSDID_SECTYPE)
 #endif
+
+/*
+ * And finally
+ */
+#define	__FBSDID(s)						\
+	FBSDID_SECTION();					\
+	__asm__(".p2align 0");					\
+	__asm__(".asciz " #s);					\
+	__asm__(".previous");
+#endif /* __FBSDID */
+#endif /* defined(STRIP_FBSDID) || defined(lint) */
 #endif
 
 #ifndef	__RCSID
--- /usr/src/sys/kern/kern_mib.c	2007-12-30 13:54:27.000000000 +0000
+++ src/sys/kern/kern_mib.c	2007-12-30 22:09:39.000000000 +0000
@@ -38,6 +38,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD: src/sys/kern/kern_mib.c,v 1.85 2007/12/04 12:28:07 kib Exp $");
 
+#include "opt_ddb.h"
 #include "opt_posix.h"
 #include "opt_config.h"
 
@@ -308,6 +309,106 @@
     CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, sysctl_kern_securelvl,
     "I", "Current secure level");
 
+/*
+ * If STRIP_FBSDID is defined it means we should save as much as
+ * possible in terms of the kernel size. Handle "kern.srcids" and "show
+ * srcids" DDB command only in !STRIP_FBSDID case. Otherwise, we'd need
+ * at least one thing lying in the srcid magic section so that we
+ * wouldn't be getting an error about __(start|stop)_set_srcid being
+ * undefined due to non-existent .srcid section; and it all would be
+ * just to get useless output..
+ */
+#ifndef STRIP_FBSDID
+
+/*
+ * Based on __FBSDID format, skip common parts that bring no valueable
+ * information in this context.
+ */
+static void __unused
+srcid_fname(char *id, char **ret, int *retlen)
+{
+	char *p = NULL;
+	int l = 0;
+
+	KASSERT(id != NULL, ("id == NULL"));
+	KASSERT(ret != NULL, ("p == NULL"));
+	KASSERT(retlen != NULL, ("len == NULL"));
+
+	p = strstr(id, "$FreeBSD: ");
+	if (p != NULL)
+		id += strlen("$FreeBSD: ");
+	l = strlen(id);
+	p = strstr(id, " Exp $");
+	if (p != NULL)
+		l = p - id;
+	*ret = id;
+	*retlen = l;
+}
+
+
+/*
+ * Magic generated by the gcc(1) to mark the section ranges with special
+ * variable names.
+ */
+extern char __start_set_srcid[];
+extern char __stop_set_srcid[];
+
+#define	FBSDID_BEGIN	(&__start_set_srcid[0])
+#define	FBSDID_END	(&__stop_set_srcid[0])
+
+/*
+ * Return all __FBSDID tags. The output is huge.
+ */
+static int
+sysctl_kern_srcids(SYSCTL_HANDLER_ARGS)
+{
+	char *bid = FBSDID_BEGIN;
+	char *eid = FBSDID_END;
+	char *s;
+	int idlen;
+	char *id;
+	int error = 0;
+
+	for (s = bid; s < eid; s++) {
+		srcid_fname(s, &id, &idlen);
+		error = sysctl_handle_opaque(oidp, "\n", 1, req);
+		if (error)
+			break;
+		error = sysctl_handle_opaque(oidp, id, idlen, req);
+		if (error)
+			break;
+		s += strlen(s);
+	}
+	error = sysctl_handle_opaque(oidp, "\0", 1, req);
+	if (error)
+		return (error);
+	return (error);
+}
+SYSCTL_PROC(_kern, OID_AUTO, srcids, CTLTYPE_STRING|CTLFLAG_RD, 0, 0,
+    sysctl_kern_srcids, "A", "Revision control tags for kernel sources");
+
+#ifdef DDB
+#include <ddb/ddb.h>
+
+DB_SHOW_COMMAND(srcids, db_srcid_list)
+{
+	char *bid = FBSDID_BEGIN;
+	char *eid = FBSDID_END;
+	char *s;
+	int slen;
+	int idlen;
+	char *id;
+
+	for (s = bid; s < eid; s++) {
+		srcid_fname(s, &id, &idlen);
+		db_printf("%.*s\n", idlen, id);
+		slen = strlen(s);
+		s += slen;
+	}
+}
+#endif
+#endif /* STRIP_FBSDID */
+
 #ifdef INCLUDE_CONFIG_FILE
 /* Actual kernel configuration options. */
 extern char kernconfstring[];