7299 want dnlc walker for mdb

Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Gordon Ross <gordon.w.ross@gmail.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

usr/src/cmd/mdb/common/modules/genunix/Makefile.files

@@ -21,7 +21,7 @@
 #
 # Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 # Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
-# Copyright (c) 2013, Joyent, Inc.  All rights reserved.
+# Copyright 2016 Joyent, Inc.
 # Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
@@ -44,6 +44,7 @@ GENUNIX_SRCS =		\
 	ddi_periodic.c	\
 	devinfo.c	\
 	dist.c		\
+	dnlc.c		\
 	findstack.c	\
 	findstack_subr.c \
 	fm.c		\

usr/src/cmd/mdb/common/modules/genunix/dnlc.c

@@ -0,0 +1,104 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * Copyright 2016 Joyent, Inc.
+ */
+
+#include "dnlc.h"
+
+#include <mdb/mdb_modapi.h>
+#include <sys/dnlc.h>
+
+typedef struct dnlc_walk {
+	int dw_hashsz;
+	int dw_index;
+	uintptr_t dw_hash;
+	uintptr_t dw_head;
+} dnlc_walk_t;
+
+
+int
+dnlc_walk_init(mdb_walk_state_t *wsp)
+{
+	dnlc_walk_t *dwp;
+
+	if (wsp->walk_addr != NULL) {
+		mdb_warn("dnlc walk doesn't support global walks\n");
+		return (WALK_ERR);
+	}
+
+	dwp = mdb_zalloc(sizeof (dnlc_walk_t), UM_SLEEP);
+	if (mdb_readvar(&dwp->dw_hashsz, "nc_hashsz") == -1 ||
+	    dwp->dw_hashsz <= 0) {
+		mdb_warn("failed to read 'nc_hashsz'\n");
+		mdb_free(dwp, sizeof (dnlc_walk_t));
+		return (WALK_ERR);
+	}
+	if (dwp->dw_hashsz <= 0) {
+		mdb_warn("invalid 'nc_hashsz' value\n");
+		mdb_free(dwp, sizeof (dnlc_walk_t));
+		return (WALK_ERR);
+	}
+	if (mdb_readvar(&dwp->dw_hash, "nc_hash") == -1) {
+		mdb_warn("failed to read 'nc_hash'\n");
+		mdb_free(dwp, sizeof (dnlc_walk_t));
+		return (WALK_ERR);
+	}
+
+	wsp->walk_data = dwp;
+	return (WALK_NEXT);
+}
+
+int
+dnlc_walk_step(mdb_walk_state_t *wsp)
+{
+	dnlc_walk_t *dwp = wsp->walk_data;
+	nc_hash_t hash;
+	uintptr_t result, addr = wsp->walk_addr;
+
+next:
+	while (addr == dwp->dw_head || addr == NULL) {
+		if (dwp->dw_index >= dwp->dw_hashsz) {
+			return (WALK_DONE);
+		}
+		dwp->dw_head = dwp->dw_hash +
+		    (sizeof (nc_hash_t) * dwp->dw_index);
+		if (mdb_vread(&hash, sizeof (hash), dwp->dw_head) == -1) {
+			mdb_warn("failed to read nc_hash_t at %#lx",
+			    dwp->dw_hash);
+			return (WALK_ERR);
+		}
+		dwp->dw_index++;
+		addr = (uintptr_t)hash.hash_next;
+	}
+
+	result = addr;
+	if (mdb_vread(&addr, sizeof (uintptr_t), addr) == -1) {
+		/*
+		 * This entry may have become bogus since acquiring the address
+		 * from its neighbor.  Continue on if that is the case.
+		 */
+		addr = NULL;
+		goto next;
+	}
+	wsp->walk_addr = addr;
+
+	return (wsp->walk_callback(result, &result, wsp->walk_cbdata));
+}
+
+void
+dnlc_walk_fini(mdb_walk_state_t *wsp)
+{
+	dnlc_walk_t *dwp = wsp->walk_data;
+
+	mdb_free(dwp, sizeof (dnlc_walk_t));
+}

usr/src/cmd/mdb/common/modules/genunix/dnlc.h

@@ -0,0 +1,33 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * Copyright 2016 Joyent, Inc.
+ */
+
+#ifndef	_MDB_DNLC_H
+#define	_MDB_DNLC_H
+
+#include <mdb/mdb_modapi.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+extern int dnlc_walk_init(mdb_walk_state_t *);
+extern int dnlc_walk_step(mdb_walk_state_t *);
+extern void dnlc_walk_fini(mdb_walk_state_t *);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* _MDB_DNLC_H */

usr/src/cmd/mdb/common/modules/genunix/genunix.c

@@ -74,6 +74,7 @@
 #include "damap.h"
 #include "ddi_periodic.h"
 #include "devinfo.h"
+#include "dnlc.h"
 #include "findstack.h"
 #include "fm.h"
 #include "gcore.h"
@@ -4301,6 +4302,8 @@ static const mdb_walker_t walkers[] = {
 	{ "callout_table", "walk callout table array", callout_table_walk_init,
 		callout_table_walk_step, callout_table_walk_fini },
 	{ "cpu", "walk cpu structures", cpu_walk_init, cpu_walk_step },
+	{ "dnlc", "walk dnlc entries",
+		dnlc_walk_init, dnlc_walk_step, dnlc_walk_fini },
 	{ "ereportq_dump", "walk list of ereports in dump error queue",
 		ereportq_dump_walk_init, ereportq_dump_walk_step, NULL },
 	{ "ereportq_pend", "walk list of ereports in pending error queue",