Preserve bound registers for pointer pass/return

We need to save/restore bound registers and add a BND prefix before
branches in _dl_runtime_profile so that bound registers for pointer
pass and return are preserved when LD_AUDIT is used.

	[BZ #18134]
	* sysdeps/i386/configure.ac: Set HAVE_MPX_SUPPORT.
	* sysdeps/i386/configure: Regenerated.
	* sysdeps/i386/dl-trampoline.S (PRESERVE_BND_REGS_PREFIX): New.
	(_dl_runtime_profile): Save and restore Intel MPX return bound
	registers when calling _dl_call_pltexit.  Add
	PRESERVE_BND_REGS_PREFIX before return.
	* sysdeps/i386/link-defines.sym (LRV_BND0_OFFSET): New.
	(LRV_BND1_OFFSET): Likewise.
	* sysdeps/x86/bits/link.h (La_i86_retval): Add lrv_bnd0 and
	lrv_bnd1.
	* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_profile): Fix
	typo in bndmov encoding.
	* sysdeps/x86_64/dl-trampoline.h: Properly save and restore
	Intel MPX bound registers.  Add PRESERVE_BND_REGS_PREFIX before
	branch instructions to preserve bounds.

9 files changed, 119 insertions, 27 deletions

diff --git a/ChangeLog b/ChangeLog
index 1aeb84b..f8765bb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2015-07-09  Igor Zamyatin  <igor.zamyatin@intel.com>
+	    H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #18134]
+	* sysdeps/i386/configure.ac: Set HAVE_MPX_SUPPORT.
+	* sysdeps/i386/configure: Regenerated.
+	* sysdeps/i386/dl-trampoline.S (PRESERVE_BND_REGS_PREFIX): New.
+	(_dl_runtime_profile): Save and restore Intel MPX return bound
+	registers when calling _dl_call_pltexit.  Add
+	PRESERVE_BND_REGS_PREFIX before return.
+	* sysdeps/i386/link-defines.sym (LRV_BND0_OFFSET): New.
+	(LRV_BND1_OFFSET): Likewise.
+	* sysdeps/x86/bits/link.h (La_i86_retval): Add lrv_bnd0 and
+	lrv_bnd1.
+	* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_profile): Fix
+	typo in bndmov encoding.
+	* sysdeps/x86_64/dl-trampoline.h: Properly save and restore
+	Intel MPX bound registers.  Add PRESERVE_BND_REGS_PREFIX before
+	branch instructions to preserve bounds.
+
 2015-07-09  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
 	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
diff --git a/NEWS b/NEWS
index fffbb43..dda1085 100644
--- a/NEWS
+++ b/NEWS
@@ -21,13 +21,13 @@ Version 2.22
   18049, 18068, 18080, 18093, 18100, 18104, 18110, 18111, 18116, 18125,
   18128, 18138, 18185, 18196, 18197, 18206, 18210, 18211, 18217, 18219,
   18220, 18221, 18234, 18244, 18245, 18247, 18287, 18319, 18324, 18333,
-  18346, 18371, 18383, 18397, 18400, 18409, 18410, 18412, 18418, 18422,
-  18434, 18435, 18444, 18468, 18469, 18470, 18479, 18483, 18495, 18496,
-  18497, 18498, 18502, 18507, 18508, 18512, 18513, 18519, 18520, 18522,
-  18527, 18528, 18529, 18530, 18532, 18533, 18534, 18536, 18539, 18540,
-  18542, 18544, 18545, 18546, 18547, 18549, 18553, 18557, 18558, 18569,
-  18583, 18585, 18586, 18592, 18593, 18594, 18602, 18612, 18613, 18619,
-  18633, 18641, 18643, 18648.
+  18346, 18371, 18383, 18397, 18400, 18409, 18410, 18412, 18134, 18418,
+  18422, 18434, 18435, 18444, 18468, 18469, 18470, 18479, 18483, 18495,
+  18496, 18497, 18498, 18502, 18507, 18508, 18512, 18513, 18519, 18520,
+  18522, 18527, 18528, 18529, 18530, 18532, 18533, 18534, 18536, 18539,
+  18540, 18542, 18544, 18545, 18546, 18547, 18549, 18553, 18557, 18558,
+  18569, 18583, 18585, 18586, 18592, 18593, 18594, 18602, 18612, 18613,
+  18619, 18633, 18641, 18643, 18648.
 
 * Cache information can be queried via sysconf() function on s390 e.g. with
   _SC_LEVEL1_ICACHE_SIZE as argument.
diff --git a/sysdeps/i386/configure b/sysdeps/i386/configure
index 6e89b59..ab66c08 100644
--- a/sysdeps/i386/configure
+++ b/sysdeps/i386/configure
@@ -240,6 +240,33 @@ $as_echo "$libc_cv_cc_novzeroupper" >&6; }
 config_vars="$config_vars
 config-cflags-novzeroupper = $libc_cv_cc_novzeroupper"
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Intel MPX support" >&5
+$as_echo_n "checking for Intel MPX support... " >&6; }
+if ${libc_cv_asm_mpx+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.s <<\EOF
+        bndmov %bnd0,(%esp)
+EOF
+if { ac_try='${CC-cc} -c $ASFLAGS conftest.s 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+  libc_cv_asm_mpx=yes
+else
+  libc_cv_asm_mpx=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_asm_mpx" >&5
+$as_echo "$libc_cv_asm_mpx" >&6; }
+if test $libc_cv_asm_mpx == yes; then
+  $as_echo "#define HAVE_MPX_SUPPORT 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for AVX2 support" >&5
 $as_echo_n "checking for AVX2 support... " >&6; }
 if ${libc_cv_cc_avx2+:} false; then :
diff --git a/sysdeps/i386/configure.ac b/sysdeps/i386/configure.ac
index 35c4522..a3f3067 100644
--- a/sysdeps/i386/configure.ac
+++ b/sysdeps/i386/configure.ac
@@ -88,6 +88,21 @@ LIBC_TRY_CC_OPTION([-mno-vzeroupper],
 ])
 LIBC_CONFIG_VAR([config-cflags-novzeroupper], [$libc_cv_cc_novzeroupper])
 
+dnl Check whether asm supports Intel MPX
+AC_CACHE_CHECK(for Intel MPX support, libc_cv_asm_mpx, [dnl
+cat > conftest.s <<\EOF
+        bndmov %bnd0,(%esp)
+EOF
+if AC_TRY_COMMAND(${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD); then
+  libc_cv_asm_mpx=yes
+else
+  libc_cv_asm_mpx=no
+fi
+rm -f conftest*])
+if test $libc_cv_asm_mpx == yes; then
+  AC_DEFINE(HAVE_MPX_SUPPORT)
+fi
+
 dnl Check if -mavx2 works.
 AC_CACHE_CHECK(for AVX2 support, libc_cv_cc_avx2, [dnl
 LIBC_TRY_CC_OPTION([-mavx2], [libc_cv_cc_avx2=yes], [libc_cv_cc_avx2=no])
diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
index 7c72b03..8a2fd8d 100644
--- a/sysdeps/i386/dl-trampoline.S
+++ b/sysdeps/i386/dl-trampoline.S
@@ -19,6 +19,12 @@
 #include <sysdep.h>
 #include <link-defines.h>
 
+#ifdef HAVE_MPX_SUPPORT
+# define PRESERVE_BND_REGS_PREFIX bnd
+#else
+# define PRESERVE_BND_REGS_PREFIX .byte 0xf2
+#endif
+
 	.text
 	.globl _dl_runtime_resolve
 	.type _dl_runtime_resolve, @function
@@ -172,6 +178,13 @@ _dl_runtime_profile:
 	movl %edx, LRV_EDX_OFFSET(%esp)
 	fstpt LRV_ST0_OFFSET(%esp)
 	fstpt LRV_ST1_OFFSET(%esp)
+#ifdef HAVE_MPX_SUPPORT
+	bndmov %bnd0, LRV_BND0_OFFSET(%esp)
+	bndmov %bnd1, LRV_BND1_OFFSET(%esp)
+#else
+	.byte 0x66,0x0f,0x1b,0x44,0x24,LRV_BND0_OFFSET
+	.byte 0x66,0x0f,0x1b,0x4c,0x24,LRV_BND1_OFFSET
+#endif
 	pushl %esp
 	cfi_adjust_cfa_offset (4)
 	# Address of La_i86_regs area.
@@ -185,9 +198,17 @@ _dl_runtime_profile:
 	movl LRV_EDX_OFFSET(%esp), %edx
 	fldt LRV_ST1_OFFSET(%esp)
 	fldt LRV_ST0_OFFSET(%esp)
+#ifdef HAVE_MPX_SUPPORT
+	bndmov LRV_BND0_OFFSET(%esp), %bnd0
+	bndmov LRV_BND1_OFFSET(%esp), %bnd1
+#else
+	.byte 0x66,0x0f,0x1a,0x44,0x24,LRV_BND0_OFFSET
+	.byte 0x66,0x0f,0x1a,0x4c,0x24,LRV_BND1_OFFSET
+#endif
 	# Restore stack before return.
 	addl $(LRV_SIZE + 4 + LR_SIZE + 4), %esp
 	cfi_adjust_cfa_offset (-(LRV_SIZE + 4 + LR_SIZE + 4))
+	PRESERVE_BND_REGS_PREFIX
 	ret
 	cfi_endproc
 	.size _dl_runtime_profile, .-_dl_runtime_profile
diff --git a/sysdeps/i386/link-defines.sym b/sysdeps/i386/link-defines.sym
index a63dcb9..0995adb 100644
--- a/sysdeps/i386/link-defines.sym
+++ b/sysdeps/i386/link-defines.sym
@@ -16,3 +16,5 @@ LRV_EAX_OFFSET		offsetof (struct La_i86_retval, lrv_eax)
 LRV_EDX_OFFSET		offsetof (struct La_i86_retval, lrv_edx)
 LRV_ST0_OFFSET		offsetof (struct La_i86_retval, lrv_st0)
 LRV_ST1_OFFSET		offsetof (struct La_i86_retval, lrv_st1)
+LRV_BND0_OFFSET		offsetof (struct La_i86_retval, lrv_bnd0)
+LRV_BND1_OFFSET		offsetof (struct La_i86_retval, lrv_bnd1)
diff --git a/sysdeps/x86/bits/link.h b/sysdeps/x86/bits/link.h
index 3f559c9..0bf9b9a 100644
--- a/sysdeps/x86/bits/link.h
+++ b/sysdeps/x86/bits/link.h
@@ -38,6 +38,8 @@ typedef struct La_i86_retval
   uint32_t lrv_edx;
   long double lrv_st0;
   long double lrv_st1;
+  uint64_t lrv_bnd0;
+  uint64_t lrv_bnd1;
 } La_i86_retval;
 
 
diff --git a/sysdeps/x86_64/dl-trampoline.S b/sysdeps/x86_64/dl-trampoline.S
index 5f9b35d..b151d35 100644
--- a/sysdeps/x86_64/dl-trampoline.S
+++ b/sysdeps/x86_64/dl-trampoline.S
@@ -206,8 +206,8 @@ _dl_runtime_profile:
 #  else
 	.byte 0x66,0x0f,0x1b,0x84,0x24;.long (LR_BND_OFFSET)
 	.byte 0x66,0x0f,0x1b,0x8c,0x24;.long (LR_BND_OFFSET + BND_SIZE)
-	.byte 0x66,0x0f,0x1b,0x84,0x24;.long (LR_BND_OFFSET + BND_SIZE*2)
-	.byte 0x66,0x0f,0x1b,0x8c,0x24;.long (LR_BND_OFFSET + BND_SIZE*3)
+	.byte 0x66,0x0f,0x1b,0x94,0x24;.long (LR_BND_OFFSET + BND_SIZE*2)
+	.byte 0x66,0x0f,0x1b,0x9c,0x24;.long (LR_BND_OFFSET + BND_SIZE*3)
 #  endif
 # endif
 
diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
index 0e5a6fb..d542428 100644
--- a/sysdeps/x86_64/dl-trampoline.h
+++ b/sysdeps/x86_64/dl-trampoline.h
@@ -63,20 +63,6 @@
 	movaps (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp), %xmm6
 	movaps (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp), %xmm7
 
-#ifndef __ILP32__
-# ifdef HAVE_MPX_SUPPORT
-	bndmov 		    (LR_BND_OFFSET)(%rsp), %bnd0  # Restore bound
-	bndmov (LR_BND_OFFSET +   BND_SIZE)(%rsp), %bnd1  # registers.
-	bndmov (LR_BND_OFFSET + BND_SIZE*2)(%rsp), %bnd2
-	bndmov (LR_BND_OFFSET + BND_SIZE*3)(%rsp), %bnd3
-# else
-	.byte 0x66,0x0f,0x1a,0x84,0x24;.long (LR_BND_OFFSET)
-	.byte 0x66,0x0f,0x1a,0x8c,0x24;.long (LR_BND_OFFSET + BND_SIZE)
-	.byte 0x66,0x0f,0x1a,0x94,0x24;.long (LR_BND_OFFSET + BND_SIZE*2)
-	.byte 0x66,0x0f,0x1a,0x9c,0x24;.long (LR_BND_OFFSET + BND_SIZE*3)
-# endif
-#endif
-
 #ifdef RESTORE_AVX
 	/* Check if any xmm0-xmm7 registers are changed by audit
 	   module.  */
@@ -154,8 +140,24 @@
 
 1:
 #endif
+
+#ifndef __ILP32__
+# ifdef HAVE_MPX_SUPPORT
+	bndmov              (LR_BND_OFFSET)(%rsp), %bnd0  # Restore bound
+	bndmov (LR_BND_OFFSET +   BND_SIZE)(%rsp), %bnd1  # registers.
+	bndmov (LR_BND_OFFSET + BND_SIZE*2)(%rsp), %bnd2
+	bndmov (LR_BND_OFFSET + BND_SIZE*3)(%rsp), %bnd3
+# else
+	.byte 0x66,0x0f,0x1a,0x84,0x24;.long (LR_BND_OFFSET)
+	.byte 0x66,0x0f,0x1a,0x8c,0x24;.long (LR_BND_OFFSET + BND_SIZE)
+	.byte 0x66,0x0f,0x1a,0x94,0x24;.long (LR_BND_OFFSET + BND_SIZE*2)
+	.byte 0x66,0x0f,0x1a,0x9c,0x24;.long (LR_BND_OFFSET + BND_SIZE*3)
+# endif
+#endif
+
 	mov  16(%rbx), %R10_LP	# Anything in framesize?
 	test %R10_LP, %R10_LP
+	PRESERVE_BND_REGS_PREFIX
 	jns 3f
 
 	/* There's nothing in the frame size, so there
@@ -174,6 +176,7 @@
 	addq $48, %rsp		# Adjust the stack to the return value
 				# (eats the reloc index and link_map)
 	cfi_adjust_cfa_offset(-48)
+	PRESERVE_BND_REGS_PREFIX
 	jmp *%r11		# Jump to function address.
 
 3:
@@ -200,6 +203,7 @@
 	movq 32(%rdi), %rsi
 	movq 40(%rdi), %rdi
 
+	PRESERVE_BND_REGS_PREFIX
 	call *%r11
 
 	mov 24(%rbx), %rsp	# Drop the copied stack content
@@ -280,11 +284,11 @@
 
 #ifndef __ILP32__
 # ifdef HAVE_MPX_SUPPORT
-	bndmov LRV_BND0_OFFSET(%rcx), %bnd0  # Restore bound registers.
-	bndmov LRV_BND1_OFFSET(%rcx), %bnd1
+	bndmov LRV_BND0_OFFSET(%rsp), %bnd0  # Restore bound registers.
+	bndmov LRV_BND1_OFFSET(%rsp), %bnd1
 # else
-	.byte  0x66,0x0f,0x1a,0x81;.long (LRV_BND0_OFFSET)
-	.byte  0x66,0x0f,0x1a,0x89;.long (LRV_BND1_OFFSET)
+	.byte  0x66,0x0f,0x1a,0x84,0x24;.long (LRV_BND0_OFFSET)
+	.byte  0x66,0x0f,0x1a,0x8c,0x24;.long (LRV_BND1_OFFSET)
 # endif
 #endif
 
@@ -299,6 +303,7 @@
 	addq $48, %rsp		# Adjust the stack to the return value
 				# (eats the reloc index and link_map)
 	cfi_adjust_cfa_offset(-48)
+	PRESERVE_BND_REGS_PREFIX
 	retq
 
 #ifdef MORE_CODE