Commit Graph

3 Commits

Author SHA1 Message Date
Fangrui Song
bf433b849a elf: Remove Intel MPX support (lazy PLT, ld.so profile, and LD_AUDIT)
Intel MPX failed to gain wide adoption and has been deprecated for a
while. GCC 9.1 removed Intel MPX support. Linux kernel removed MPX in
2019.

This patch removes the support code from the dynamic loader.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-10-11 11:14:02 -07:00
Igor Zamyatin
14c5cbabc2 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.
2015-07-09 06:50:12 -07:00
H.J. Lu
ddd85a65b6 Add and use sysdeps/i386/link-defines.sym
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.
2015-07-07 05:23:40 -07:00