x86-64: Properly align La_x86_64_retval to VEC_SIZE [BZ #22715]

_dl_runtime_profile calls _dl_call_pltexit, passing a pointer to
La_x86_64_retval which is allocated on stack.  The lrv_vector0
field in La_x86_64_retval must be aligned to size of vector register.
When allocating stack space for La_x86_64_retval, we need to make sure
that the address of La_x86_64_retval + RV_VECTOR0_OFFSET is aligned to
VEC_SIZE.  This patch checks the alignment of the lrv_vector0 field
and pads the stack space if needed.

Tested with x32 and x86-64 on SSE4, AVX and AVX512 machines.  It fixed

FAIL: elf/tst-audit10
FAIL: elf/tst-audit4
FAIL: elf/tst-audit5
FAIL: elf/tst-audit6
FAIL: elf/tst-audit7

on x32 AVX512 machine.

(cherry picked from commit 207a72e2988c6d6343f50fe0128eb4fc4edfdd15)

	[BZ #22715]
	* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_profile): Properly
	align La_x86_64_retval to VEC_SIZE.

diff --git a/ChangeLog b/ChangeLog
index 95be6382d9787afbb464ba50403c059264822604..ef4563f74a025fc40d4fa6cd2c9d2473aba9481f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-19  H.J. Lu  <hongjiu.lu@intel.com>
+
+       [BZ #22715]
+       * sysdeps/x86_64/dl-trampoline.h (_dl_runtime_profile): Properly
+       align La_x86_64_retval to VEC_SIZE.
+
 2018-01-11  Florian Weimer  <fweimer@redhat.com>
 
        * sysdeps/x86/cpu-features.c (init_cpu_features): Move check for

diff --git a/NEWS b/NEWS
index 7dd7193225de606173b16305601f29bfc6d4ffd5..9bbcfd137ac0816a4251e7b21b6efe76bfc53abe 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -48,6 +48,7 @@ The following bugs are resolved with this release:
   [21624] Unsafe alloca allows local attackers to alias stack and heap (CVE-2017-1000366)
   [21666] Avoid .symver on common symbols
   [22641] x86: Fix mis-merge of XSAVE ld.so trampoline selection
+  [22715] x86-64: Properly align La_x86_64_retval to VEC_SIZE
 
 \f
 Version 2.23

diff --git a/sysdeps/x86_64/dl-trampoline.h b/sysdeps/x86_64/dl-trampoline.h
index aadc91d38aaa9f1c3219eae763d5a31633257efd..c5f9237151d8aa6c98349ef17953e7b64cb74f74 100644 (file)
--- a/sysdeps/x86_64/dl-trampoline.h
+++ b/sysdeps/x86_64/dl-trampoline.h
@@ -446,8 +446,16 @@ _dl_runtime_profile:
 # ifdef RESTORE_AVX
        /* sizeof(La_x86_64_retval).  Need extra space for 2 SSE
           registers to detect if xmm0/xmm1 registers are changed
-          by audit module.  */
-       sub $(LRV_SIZE + XMM_SIZE*2), %RSP_LP
+          by audit module.  Since rsp is aligned to VEC_SIZE, we
+          need to make sure that the address of La_x86_64_retval +
+          LRV_VECTOR0_OFFSET is aligned to VEC_SIZE.  */
+#  define LRV_SPACE (LRV_SIZE + XMM_SIZE*2)
+#  define LRV_MISALIGNED ((LRV_SIZE + LRV_VECTOR0_OFFSET) & (VEC_SIZE - 1))
+#  if LRV_MISALIGNED == 0
+       sub $LRV_SPACE, %RSP_LP
+#  else
+       sub $(LRV_SPACE + VEC_SIZE - LRV_MISALIGNED), %RSP_LP
+#  endif
 # else
        sub $LRV_SIZE, %RSP_LP  # sizeof(La_x86_64_retval)
 # endif