Binaries can opt-in to using BTI via an ELF object file marking.
The dynamic linker has to then mprotect the executable segments
with PROT_BTI. In case of static linked executables or in case
of the dynamic linker itself, PROT_BTI protection is done by the
operating system.
On AArch64 glibc uses PT_GNU_PROPERTY instead of PT_NOTE to check
the properties of a binary because PT_NOTE can be unreliable with
old linkers (old linkers just append the notes of input objects
together and add them to the output without checking them for
consistency which means multiple incompatible GNU property notes
can be present in PT_NOTE).
BTI property is handled in the loader even if glibc is not built
with BTI support, so in theory user code can be BTI protected
independently of glibc. In practice though user binaries are not
marked with the BTI property if glibc has no support because the
static linked libc objects (crt files, libc_nonshared.a) are
unmarked.
This patch relies on Linux userspace API that is not yet in a
linux release but in v5.8-rc1 so scheduled to be in Linux 5.8.
Co-authored-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch adds new AArch64 HWCAPs from Linux 5.0 to the AArch64
bits/hwcap.h and dl-procinfo.c.
Tested (compilation only) with build-many-glibcs.py for
aarch64-linux-gnu.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_SB): New
macro.
(HWCAP_PACA): Likewise.
(HWCAP_PACG): Likewise.
* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c (_DL_HWCAP_COUNT):
Increase to 32.
(_dl_aarch64_cap_flags): Add new entries for new HWCAPs.
bits/hwcap.h should be updated together with dl-procinfo.c.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h: Add comment.
* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c (_DL_HWCAP_COUNT):
Update.
This patch adds the HWCAP_SSBS constant from Linux 4.20 to the AArch64
bits/hwcap.h.
Tested with build-many-glibcs.py for aarch64-linux-gnu.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_SSBS): New
macro.
Linux 4.17 adds four new AArch64 hwcap values. This patch adds them
to glibc's AArch64 bits/hwcap.h, with corresponding dl-procinfo.c
updates.
Tested with build-many-glibcs.py for aarch64.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_DIT): New
macro.
(HWCAP_USCAT): Likewise.
(HWCAP_ILRCPC): Likewise.
(HWCAP_FLAGM): Likewise.
* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c (_DL_HWCAP_COUNT):
Increase to 28.
(_dl_aarch64_cap_flags): Add new flag names.
This patch updates the aarch64 bits/hwcap.h and dl-procinfo.c for the
new HWCAP_ASIMDFHM value in Linux 4.16.
Tested with build-many-glibcs.py for aarch64-linux-gnu.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_ASIMDFHM):
New macro.
* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c (_DL_HWCAP_COUNT):
Increase to 24.
(_dl_aarch64_cap_flags): Add asimdfhm.
Define new HWCAP bits and add their name to dl-procinfo.c following
the linux definitions. Synchronizing with v4.15-rc8 version of linux,
these are not expected to change before the 4.15 release.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_SHA3): Define.
(HWCAP_SM3, HWCAP_SM4, HWCAP_ASIMDDP, HWCAP_SHA512, HWCAP_SVE): Define.
* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
(_dl_aarch64_cap_flags): Update.
(_DL_HWCAP_COUNT): Update.
This patch adds the HWCAP_DCPOP macro from Linux 4.14 to the AArch64
bits/hwcap.h.
Tested (compilation only) for aarch64 with build-many-glibcs.py.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_DCPOP): New
macro.
This patch adds the HWCAP_JSCVT, HWCAP_FCMA and HWCAP_LRCPC macros
from Linux 4.12 to the AArch64 bits/hwcap.h.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_FCMA): New macro.
(HWCAP_JSCVT, HWCAP_LRCPC): Likewise.
This patch adds the HWCAP_ASIMDRDM macro from Linux 4.11 to the
AArch64 bits/hwcap.h.
Tested (compilation only) with build-many-glibcs.py.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_ASIMDRDM):
New macro.
AArch64 uses HWCAP bits but they are not defined in sys/auxv.h.
This patch adds a copy of the linux v4.6 arm64 uapi asm/hwcap.h
definitions.
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h: New.
Sudakshina Das
Szabolcs Nagy
Joseph Myers
Paul Eggert
Steve Ellcey