diff --git a/sbin/sysctl/sysctl.c b/sbin/sysctl/sysctl.c
index 13596450d2e..578260d6318 100644
--- a/sbin/sysctl/sysctl.c
+++ b/sbin/sysctl/sysctl.c
@@ -48,6 +48,10 @@ static const char rcsid[] =
 #include <sys/sysctl.h>
 #include <sys/vmmeter.h>
 
+#if defined(__amd64__) || defined(__i386__)
+#include <machine/pc/bios.h>
+#endif
+
 #include <ctype.h>
 #include <err.h>
 #include <errno.h>
@@ -541,6 +545,27 @@ S_vmtotal(int l2, void *p)
 	return (0);
 }
 
+#if defined(__amd64__) || defined(__i386__)
+static int
+S_bios_smap_xattr(int l2, void *p)
+{
+	struct bios_smap_xattr *smap, *end;
+
+	if (l2 % sizeof(*smap) != 0) {
+		warnx("S_bios_smap_xattr %d is not a multiple of %zu", l2,
+		    sizeof(*smap));
+		return (1);
+	}
+
+	end = (struct bios_smap_xattr *)((char *)p + l2);
+	for (smap = p; smap < end; smap++)
+		printf("\nSMAP type=%02x, xattr=%02x, base=%016jx, len=%016jx",
+		    smap->type, smap->xattr, (uintmax_t)smap->base,
+		    (uintmax_t)smap->length);
+	return (0);
+}
+#endif
+
 static int
 set_IK(const char *str, int *val)
 {
@@ -793,6 +818,10 @@ show_var(int *oid, int nlen)
 			func = S_loadavg;
 		else if (strcmp(fmt, "S,vmtotal") == 0)
 			func = S_vmtotal;
+#if defined(__amd64__) || defined(__i386__)
+		else if (strcmp(fmt, "S,bios_smap_xattr") == 0)
+			func = S_bios_smap_xattr;
+#endif
 		else
 			func = NULL;
 		if (func) {
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index f02045d6414..bb0bc210e68 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -2090,6 +2090,42 @@ cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
 	pcpu->pc_acpi_id = 0xffffffff;
 }
 
+static int
+smap_sysctl_handler(SYSCTL_HANDLER_ARGS)
+{
+	struct bios_smap *smapbase;
+	struct bios_smap_xattr smap;
+	caddr_t kmdp;
+	uint32_t *smapattr;
+	int count, error, i;
+
+	/* Retrieve the system memory map from the loader. */
+	kmdp = preload_search_by_type("elf kernel");
+	if (kmdp == NULL)
+		kmdp = preload_search_by_type("elf64 kernel");
+	smapbase = (struct bios_smap *)preload_search_info(kmdp,
+	    MODINFO_METADATA | MODINFOMD_SMAP);
+	if (smapbase == NULL)
+		return (0);
+	smapattr = (uint32_t *)preload_search_info(kmdp,
+	    MODINFO_METADATA | MODINFOMD_SMAP_XATTR);
+	count = *((uint32_t *)smapbase - 1) / sizeof(*smapbase);
+	error = 0;
+	for (i = 0; i < count; i++) {
+		smap.base = smapbase[i].base;
+		smap.length = smapbase[i].length;
+		smap.type = smapbase[i].type;
+		if (smapattr != NULL)
+			smap.xattr = smapattr[i];
+		else
+			smap.xattr = 0;
+		error = SYSCTL_OUT(req, &smap, sizeof(smap));
+	}
+	return (error);
+}
+SYSCTL_PROC(_machdep, OID_AUTO, smap, CTLTYPE_OPAQUE|CTLFLAG_RD, NULL, 0,
+    smap_sysctl_handler, "S,bios_smap_xattr", "Raw BIOS SMAP data");
+
 void
 spinlock_enter(void)
 {
diff --git a/sys/amd64/include/pc/bios.h b/sys/amd64/include/pc/bios.h
index 95ef703e498..1dbf110219b 100644
--- a/sys/amd64/include/pc/bios.h
+++ b/sys/amd64/include/pc/bios.h
@@ -51,6 +51,14 @@ struct bios_smap {
     u_int32_t	type;
 } __packed;
 
+/* Structure extended to include extended attribute field in ACPI 3.0. */
+struct bios_smap_xattr {
+    u_int64_t	base;
+    u_int64_t	length;
+    u_int32_t	type;
+    u_int32_t	xattr;
+} __packed;
+	
 /*
  * System Management BIOS
  */
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 243eab3a804..b3338a13dfb 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -3122,6 +3122,42 @@ cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
 	pcpu->pc_acpi_id = 0xffffffff;
 }
 
+static int
+smap_sysctl_handler(SYSCTL_HANDLER_ARGS)
+{
+	struct bios_smap *smapbase;
+	struct bios_smap_xattr smap;
+	caddr_t kmdp;
+	uint32_t *smapattr;
+	int count, error, i;
+
+	/* Retrieve the system memory map from the loader. */
+	kmdp = preload_search_by_type("elf kernel");
+	if (kmdp == NULL)
+		kmdp = preload_search_by_type("elf32 kernel");
+	smapbase = (struct bios_smap *)preload_search_info(kmdp,
+	    MODINFO_METADATA | MODINFOMD_SMAP);
+	if (smapbase == NULL)
+		return (0);
+	smapattr = (uint32_t *)preload_search_info(kmdp,
+	    MODINFO_METADATA | MODINFOMD_SMAP_XATTR);
+	count = *((u_int32_t *)smapbase - 1) / sizeof(*smapbase);
+	error = 0;
+	for (i = 0; i < count; i++) {
+		smap.base = smapbase[i].base;
+		smap.length = smapbase[i].length;
+		smap.type = smapbase[i].type;
+		if (smapattr != NULL)
+			smap.xattr = smapattr[i];
+		else
+			smap.xattr = 0;
+		error = SYSCTL_OUT(req, &smap, sizeof(smap));
+	}
+	return (error);
+}
+SYSCTL_PROC(_machdep, OID_AUTO, smap, CTLTYPE_OPAQUE|CTLFLAG_RD, NULL, 0,
+    smap_sysctl_handler, "S,bios_smap_xattr", "Raw BIOS SMAP data");
+
 void
 spinlock_enter(void)
 {
diff --git a/sys/i386/include/pc/bios.h b/sys/i386/include/pc/bios.h
index f757e742ef5..d1d8caff4a6 100644
--- a/sys/i386/include/pc/bios.h
+++ b/sys/i386/include/pc/bios.h
@@ -221,6 +221,14 @@ struct bios_smap {
     u_int32_t	type;
 } __packed;
 
+/* Structure extended to include extended attribute field in ACPI 3.0. */
+struct bios_smap_xattr {
+    u_int64_t	base;
+    u_int64_t	length;
+    u_int32_t	type;
+    u_int32_t	xattr;
+} __packed;
+
 /*
  * System Management BIOS
  */