Bring back LX zones.

@@ -159,11 +159,11 @@
 
 /*
  * The brand infrastructure interposes on two handlers, and we use one as a
  * NULL signpost.
  */
-static struct interposing_handler brand_tbl[2];
+static struct interposing_handler brand_tbl[3];
 
 /*
  * software prototypes for default local descriptor table
  */
 

@@ -975,10 +975,16 @@
             TRP_KPL, 0);
         set_gatesegd(&idt[T_MCE], &mcetrap, KCS_SEL, SDT_SYSIGT, TRP_KPL, 0);
         set_gatesegd(&idt[T_SIMDFPE], &xmtrap, KCS_SEL, SDT_SYSIGT, TRP_KPL, 0);
 
         /*
+         * install "int80" handler at, well, 0x80.
+         */
+        set_gatesegd(&idt0[T_INT80], &sys_int80, KCS_SEL, SDT_SYSIGT, TRP_UPL,
+            0);
+
+        /*
          * install fast trap handler at 210.
          */
         set_gatesegd(&idt[T_FASTTRAP], &fasttrap, KCS_SEL, SDT_SYSIGT, TRP_UPL,
             0);
 

@@ -999,25 +1005,31 @@
          */
         set_gatesegd(&idt[T_DTRACE_RET], &dtrace_ret, KCS_SEL,
             SDT_SYSIGT, TRP_UPL, 0);
 
         /*
-         * Prepare interposing descriptor for the syscall handler
-         * and cache copy of the default descriptor.
-         */
-        brand_tbl[0].ih_inum = T_SYSCALLINT;
-        brand_tbl[0].ih_default_desc = idt0[T_SYSCALLINT];
+-        * Prepare interposing descriptors for the branded "int80"
+-        * and syscall handlers and cache copies of the default
+-        * descriptors.
+         */
+        brand_tbl[0].ih_inum = T_INT80;
+        brand_tbl[0].ih_default_desc = idt0[T_INT80];
+        set_gatesegd(&(brand_tbl[0].ih_interp_desc), &brand_sys_int80, KCS_SEL,
+            SDT_SYSIGT, TRP_UPL, 0);
+
+        brand_tbl[1].ih_inum = T_SYSCALLINT;
+        brand_tbl[1].ih_default_desc = idt0[T_SYSCALLINT];
 
 #if defined(__amd64)
-        set_gatesegd(&(brand_tbl[0].ih_interp_desc), &brand_sys_syscall_int,
+        set_gatesegd(&(brand_tbl[1].ih_interp_desc), &brand_sys_syscall_int,
             KCS_SEL, SDT_SYSIGT, TRP_UPL, 0);
 #elif defined(__i386)
-        set_gatesegd(&(brand_tbl[0].ih_interp_desc), &brand_sys_call,
+        set_gatesegd(&(brand_tbl[1].ih_interp_desc), &brand_sys_call,
             KCS_SEL, SDT_SYSIGT, TRP_UPL, 0);
 #endif  /* __i386 */
 
-        brand_tbl[1].ih_inum = 0;
+        brand_tbl[2].ih_inum = 0;
 }
 
 #if defined(__xpv)
 
 static void