Don't use multi byte nop instructions for i386

bfd/ 2012-02-09 H.J. Lu <hongjiu.lu@intel.com> PR ld/13675 * cpu-i386.c (bfd_arch_i386_fill): Updated to support multi byte nop instructions. (bfd_arch_i386_short_nop_fill): New. (bfd_arch_i386_long_nop_fill): Likewise. Use bfd_arch_i386_short_nop_fill in 32bit bfd_arch_info initializers. Use bfd_arch_i386_long_nop_fill on 64bit bfd_arch_info initializers. * cpu-k1om.c (bfd_arch_i386_fill): Renamed to ... (bfd_arch_i386_short_nop_fill): This. Update bfd_arch_info initializers. * cpu-l1om.c: Likewise. ld/testsuite/ 2012-02-09 H.J. Lu <hongjiu.lu@intel.com> PR ld/13675 * ld-i386/tlsnopic.dd: Update no-op padding. * ld-i386/tlspic.dd: Likewise.
15 years ago · 923f257ffd
7 changed files with 74 additions and 26 deletions
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@ -1,3 +1,19 @@
+2012-02-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/13675
+	* cpu-i386.c (bfd_arch_i386_fill): Updated to support multi byte
+	nop instructions.
+	(bfd_arch_i386_short_nop_fill): New.
+	(bfd_arch_i386_long_nop_fill): Likewise.
+	Use bfd_arch_i386_short_nop_fill in 32bit bfd_arch_info
+	initializers.  Use bfd_arch_i386_long_nop_fill on 64bit
+	bfd_arch_info initializers.
+
+	* cpu-k1om.c (bfd_arch_i386_fill): Renamed to ...
+	(bfd_arch_i386_short_nop_fill): This.
+	Update bfd_arch_info initializers.
+	* cpu-l1om.c: Likewise.
+
 2012-02-08  Alan Modra  <amodra@gmail.com>

 	* elflink.c (_bfd_elf_gc_mark_rsec): Mark weakdef syms too.
--- a/bfd/cpu-i386.c
+++ b/bfd/cpu-i386.c
@ -25,7 +25,8 @@
 #include "libbfd.h"
 #include "libiberty.h"

-extern void * bfd_arch_i386_fill (bfd_size_type, bfd_boolean, bfd_boolean);
+extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
+					    bfd_boolean);

 static const bfd_arch_info_type *
 bfd_i386_compatible (const bfd_arch_info_type *a,
@ -41,16 +42,16 @@ bfd_i386_compatible (const bfd_arch_info_type *a,
  return compat;
 }

-/* Fill the buffer with zero or nop instruction if CODE is TRUE.  */
+/* Fill the buffer with zero or nop instruction if CODE is TRUE.  Use
+   multi byte nop instructions if LONG_NOP is TRUE.  */

-void *
-bfd_arch_i386_fill (bfd_size_type count,
-		    bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
-		    bfd_boolean code)
+static void *
+bfd_arch_i386_fill (bfd_size_type count, bfd_boolean code,
+		    bfd_boolean long_nop)
 {
  /* nop */
  static const char nop_1[] = { 0x90 };	
-  /* nopw */
+  /* xchg %ax,%ax */
  static const char nop_2[] = { 0x66, 0x90 };
  /* nopl (%[re]ax) */
  static const char nop_3[] = { 0x0f, 0x1f, 0x00 };
@ -74,6 +75,7 @@ bfd_arch_i386_fill (bfd_size_type count,
  static const char *const nops[] =
    { nop_1, nop_2, nop_3, nop_4, nop_5,
      nop_6, nop_7, nop_8, nop_9, nop_10 };
+  bfd_size_type nop_size = long_nop ? ARRAY_SIZE (nops) : 2;

  void *fill = bfd_malloc (count);
  if (fill == NULL)
@ -82,11 +84,11 @@ bfd_arch_i386_fill (bfd_size_type count,
  if (code)
    {
      bfd_byte *p = fill;
-      while (count >= ARRAY_SIZE (nops))
+      while (count >= nop_size)
 	{
-	  memcpy (p, nops[ARRAY_SIZE (nops) - 1], ARRAY_SIZE (nops));
-	  p += ARRAY_SIZE (nops);
-	  count -= ARRAY_SIZE (nops);
+	  memcpy (p, nops[nop_size - 1], nop_size);
+	  p += nop_size;
+	  count -= nop_size;
 	}
      if (count != 0)
 	memcpy (p, nops[count - 1], count);
@ -97,6 +99,26 @@ bfd_arch_i386_fill (bfd_size_type count,
  return fill;
 }

+/* Fill the buffer with zero or short nop instruction if CODE is TRUE.  */
+
+void *
+bfd_arch_i386_short_nop_fill (bfd_size_type count,
+			      bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
+			      bfd_boolean code)
+{
+  return bfd_arch_i386_fill (count, code, FALSE);
+}
+
+/* Fill the buffer with zero or long nop instruction if CODE is TRUE.  */
+
+static void *
+bfd_arch_i386_long_nop_fill (bfd_size_type count,
+			     bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
+			     bfd_boolean code)
+{
+  return bfd_arch_i386_fill (count, code, TRUE);
+}
+
 static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
 {
  64, /* 64 bits in a word */
@ -110,7 +132,7 @@ static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
  0
 };

@ -127,7 +149,7 @@ static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
  &bfd_x64_32_arch_intel_syntax,
 };

@ -144,7 +166,7 @@ static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
  TRUE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  &bfd_x86_64_arch_intel_syntax
 };

@ -161,7 +183,7 @@ static const bfd_arch_info_type i8086_arch =
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  &bfd_i386_arch_intel_syntax
 };

@ -178,7 +200,7 @@ static const bfd_arch_info_type bfd_x64_32_arch =
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
  &i8086_arch
 };

@ -195,7 +217,7 @@ static const bfd_arch_info_type bfd_x86_64_arch =
  FALSE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
  &bfd_x64_32_arch
 };

@ -212,6 +234,6 @@ const bfd_arch_info_type bfd_i386_arch =
  TRUE,
  bfd_i386_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  &bfd_x86_64_arch
 };
--- a/bfd/cpu-k1om.c
+++ b/bfd/cpu-k1om.c
@ -23,7 +23,8 @@
 #include "bfd.h"
 #include "libbfd.h"

-extern void * bfd_arch_i386_fill (bfd_size_type, bfd_boolean, bfd_boolean);
+extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
+					    bfd_boolean);

 static const bfd_arch_info_type bfd_k1om_arch_intel_syntax =
 {
@ -38,7 +39,7 @@ static const bfd_arch_info_type bfd_k1om_arch_intel_syntax =
  TRUE,
  bfd_default_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  0
 };

@ -55,6 +56,6 @@ const bfd_arch_info_type bfd_k1om_arch =
  TRUE,
  bfd_default_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  &bfd_k1om_arch_intel_syntax
 };
--- a/bfd/cpu-l1om.c
+++ b/bfd/cpu-l1om.c
@ -23,7 +23,8 @@
 #include "bfd.h"
 #include "libbfd.h"

-extern void * bfd_arch_i386_fill (bfd_size_type, bfd_boolean, bfd_boolean);
+extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
+					    bfd_boolean);

 static const bfd_arch_info_type bfd_l1om_arch_intel_syntax =
 {
@ -38,7 +39,7 @@ static const bfd_arch_info_type bfd_l1om_arch_intel_syntax =
  TRUE,
  bfd_default_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  0
 };

@ -55,6 +56,6 @@ const bfd_arch_info_type bfd_l1om_arch =
  TRUE,
  bfd_default_compatible,
  bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
  &bfd_l1om_arch_intel_syntax
 };
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@ -1,3 +1,9 @@
+2012-02-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/13675
+	* ld-i386/tlsnopic.dd: Update no-op padding.
+	* ld-i386/tlspic.dd: Likewise. 
+
 2012-01-31  H.J. Lu  <hongjiu.lu@intel.com>

 	PR ld/13616
--- a/ld/testsuite/ld-i386/tlsnopic.dd
+++ b/ld/testsuite/ld-i386/tlsnopic.dd
@ -156,4 +156,5 @@ Disassembly of section .text:
    10ec:	8b 5d fc[ 	]+mov    -0x4\(%ebp\),%ebx
    10ef:	c9[ 	]+leave *
    10f0:	c3[ 	]+ret *
-    10f1:	0f 1f 00[ 	]+nopl   \(%eax\)
+    10f1:	66 90[ 	]+xchg   %ax,%ax
+    10f3:	90[ 	]+nop
--- a/ld/testsuite/ld-i386/tlspic.dd
+++ b/ld/testsuite/ld-i386/tlspic.dd
@ -406,4 +406,5 @@ Disassembly of section .text:
 [0-9a-f]+:	8b 5d fc[ 	]+mov    -0x4\(%ebp\),%ebx
 [0-9a-f]+:	c9[ 	]+leave *
 [0-9a-f]+:	c3[ 	]+ret *
- [0-9a-f]+:	0f 1f 00[ 	]+nopl   \(%eax\)
+ [0-9a-f]+:	66 90[ 	]+xchg   %ax,%ax
+ [0-9a-f]+:	90[ 	]+nop