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.
Define macros for fields in La_i86_regs and La_i86_retval and use them
in dl-trampoline.S, instead of hardcoded values.
* sysdeps/i386/Makefile (gen-as-const-headers)[elf]: Add
link-defines.sym.
* sysdeps/i386/dl-trampoline.S: Include <link-defines.h>.
(_dl_runtime_profile): Use LONG_DOUBLE_SIZE, LRV_SIZE,
LRV_EAX_OFFSET, LRV_EDX_OFFSET, LRV_ST0_OFFSET, LRV_ST1_OFFSET
and LR_SIZE.
* sysdeps/i386/link-defines.sym: New file.
