svn commit: r340858 - head/libexec/rtld-elf

[Konstantin Belousov]

Author: kib
Date: Fri Nov 23 22:37:35 2018
New Revision: 340858
URL: https://svnweb.freebsd.org/changeset/base/340858

Log:
  rtld: parse FreeBSD Feature Control note on the object load.
  
  Sponsored by:	The FreeBSD Foundation
  MFC after:	2 weeks

Modified:
  head/libexec/rtld-elf/rtld.c
  head/libexec/rtld-elf/rtld.h

Modified: head/libexec/rtld-elf/rtld.c
==============================================================================
--- head/libexec/rtld-elf/rtld.c	Fri Nov 23 22:36:56 2018	(r340857)
+++ head/libexec/rtld-elf/rtld.c	Fri Nov 23 22:37:35 2018	(r340858)
@@ -1477,6 +1477,7 @@ digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_
 		    note->n_descsz != sizeof(int32_t))
 			continue;
 		if (note->n_type != NT_FREEBSD_ABI_TAG &&
+		    note->n_type != NT_FREEBSD_FEATURE_CTL &&
 		    note->n_type != NT_FREEBSD_NOINIT_TAG)
 			continue;
 		note_name = (const char *)(note + 1);
@@ -1490,6 +1491,13 @@ digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_
 			p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
 			obj->osrel = *(const int32_t *)(p);
 			dbg("note osrel %d", obj->osrel);
+			break;
+		case NT_FREEBSD_FEATURE_CTL:
+			/* FreeBSD ABI feature control note */
+			p = (uintptr_t)(note + 1);
+			p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
+			obj->fctl0 = *(const uint32_t *)(p);
+			dbg("note fctl0 %#x", obj->fctl0);
 			break;
 		case NT_FREEBSD_NOINIT_TAG:
 			/* FreeBSD 'crt does not call init' note */

Modified: head/libexec/rtld-elf/rtld.h
==============================================================================
--- head/libexec/rtld-elf/rtld.h	Fri Nov 23 22:36:56 2018	(r340857)
+++ head/libexec/rtld-elf/rtld.h	Fri Nov 23 22:37:35 2018	(r340858)
@@ -235,6 +235,7 @@ typedef struct Struct_Obj_Entry {
     int fini_array_num; 	/* Number of entries in fini_array */
 
     int32_t osrel;		/* OSREL note value */
+    uint32_t fctl0;		/* FEATURE_CONTROL note desc[0] value */
 
     bool mainprog : 1;		/* True if this is the main program */
     bool rtld : 1;		/* True if this is the dynamic linker */