This patch adds SSE, AVX and AVX512 versions of _dl_runtime_resolve
and _dl_runtime_profile, which save and restore the first 8 vector
registers used for parameter passing. elf_machine_runtime_setup
selects the proper _dl_runtime_resolve or _dl_runtime_profile based
on _dl_x86_cpu_features. It avoids race condition caused by
FOREIGN_CALL macros, which are only used for x86-64.
Performance impact of saving and restoring 8 vector registers are
negligible on Nehalem, Sandy Bridge, Ivy Bridge and Haswell when
ld.so is optimized with SSE2.
[BZ #15128]
* sysdeps/x86_64/Makefile [$(subdir) == elf] (tests): Add
ifuncmain8.
(modules-names): Add ifuncmod8.
($(objpfx)ifuncmain8): New rule.
* sysdeps/x86_64/dl-machine.h: Include <dl-procinfo.h> and
<cpuid.h>.
(elf_machine_runtime_setup): Use _dl_runtime_resolve_sse,
_dl_runtime_resolve_avx, or _dl_runtime_resolve_avx512,
_dl_runtime_profile_sse, _dl_runtime_profile_avx, or
_dl_runtime_profile_avx512, based on HAS_ARCH_FEATURE.
* sysdeps/x86_64/dl-trampoline.S: Rewrite.
* sysdeps/x86_64/dl-trampoline.h: Likewise.
* sysdeps/x86_64/ifuncmain8.c: New file.
* sysdeps/x86_64/ifuncmod8.c: Likewise.
* sysdeps/x86_64/nptl/tcb-offsets.sym (RTLD_SAVESPACE_SSE):
Removed.
* sysdeps/x86_64/nptl/tls.h (__128bits): Removed.
(tcbhead_t): Change rtld_must_xmm_save to __glibc_unused1.
Change rtld_savespace_sse to __glibc_unused2.
(RTLD_CHECK_FOREIGN_CALL): Removed.
(RTLD_ENABLE_FOREIGN_CALL): Likewise.
(RTLD_PREPARE_FOREIGN_CALL): Likewise.
(RTLD_FINALIZE_FOREIGN_CALL): Likewise.
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.
AVX-512 ISA adds 512-bit zmm registers. This patch updates
_dl_runtime_profile to pass zmm registers to run-time audit. It also
changes _dl_x86_64_save_sse and _dl_x86_64_restore_sse to upport zmm
registers, which are called when only when RTLD_PREPARE_FOREIGN_CALL
is used. Its performance impact is minimum.
* config.h.in (HAVE_AVX512_SUPPORT): New #undef.
(HAVE_AVX512_ASM_SUPPORT): Likewise.
* sysdeps/x86_64/bits/link.h (La_x86_64_zmm): New.
(La_x86_64_vector): Add zmm.
* sysdeps/x86_64/Makefile (tests): Add tst-audit10.
(modules-names): Add tst-auditmod10a and tst-auditmod10b.
($(objpfx)tst-audit10): New target.
($(objpfx)tst-audit10.out): Likewise.
(tst-audit10-ENV): New.
(AVX512-CFLAGS): Likewise.
(CFLAGS-tst-audit10.c): Likewise.
(CFLAGS-tst-auditmod10a.c): Likewise.
(CFLAGS-tst-auditmod10b.c): Likewise.
* sysdeps/x86_64/configure.ac: Set config-cflags-avx512,
HAVE_AVX512_SUPPORT and HAVE_AVX512_ASM_SUPPORT.
* sysdeps/x86_64/configure: Regenerated.
* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_profile): Add
AVX-512 zmm register support.
(_dl_x86_64_save_sse): Likewise.
(_dl_x86_64_restore_sse): Likewise.
* sysdeps/x86_64/dl-trampoline.h: Updated to support different
size vector registers.
* sysdeps/x86_64/link-defines.sym (YMM_SIZE): New.
(ZMM_SIZE): Likewise.
* sysdeps/x86_64/tst-audit10.c: New file.
* sysdeps/x86_64/tst-auditmod10a.c: Likewise.
* sysdeps/x86_64/tst-auditmod10b.c: Likewise.
This patch fixes mixed SSE/AVX audit and checks AVX only once in
_dl_runtime_profile. When an AVX or SSE register value in pltenter is
modified, we have to make sure that the SSE part value is the same in both
lr_xmm and lr_vector fields so that pltexit will get the correct value
from either lr_xmm or lr_vector fields. AVX-enabled pltenter should
update both lr_xmm and lr_vector fields to support stacked AVX/SSE
pltenter functions.
The original AVX patch used a function pointer to handle the difference
between machines with and without AVX support. This is insecure. A
well-placed memory exploit could lead to redirection of the execution.
Using a variable and several tests is a bit slower but cannot be
exploited in this way.
