[PATCH v2 0/8] Implement assembly cortex-M PACBTI functionality

This patch series modifies hand-written assembly files for Arm targets,
conditionally enabling branch target identification as well as address
return signature and verification based on Armv8.1-M Pointer
Authentication [1] using ACLE feature test macros at compile-time [2].

The incorportaion of PACBTI functionality in function prologues/
epilogues is dictated by the arguments passed to the
`-mbranch-protection' flag at the time of Newlib compilation.

Regression tested on arm-none-eabi with and without MVE extension and
for Newlib and Newlib-nano.

[1]
<https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension>
[2] <https://developer.arm.com/documentation/101028/0012/5--Feature-test-macros>

Victor Do Nascimento (8):
  newlib: libc: define M-profile PACBTI-enablement macros
  newlib: libc: strcmp M-profile PACBTI-enablement
  newlib: libc: strlen M-profile PACBTI-enablement
  newlib: libc: memchr M-profile PACBTI-enablement
  newlib: libc: memcpy M-profile PACBTI-enablement
  newlib: libc: setjmp/longjmp M-profile PACBTI-enablement
  newlib: libc: aeabi_memmove M-profile PACBTI-enablement
  newlib: libc: aeabi_memset M-profile PACBTI-enablement

 .../libc/machine/arm/aeabi_memmove-thumb2.S   | 54 ++++++++++++--
 newlib/libc/machine/arm/aeabi_memset-thumb2.S | 47 +++++++++++-
 newlib/libc/machine/arm/memchr.S              | 55 ++++++++++++--
 newlib/libc/machine/arm/memcpy-armv7m.S       | 74 +++++++++++++++++--
 newlib/libc/machine/arm/pacbti.h              | 64 ++++++++++++++++
 newlib/libc/machine/arm/setjmp.S              | 33 ++++++++-
 newlib/libc/machine/arm/strcmp-arm-tiny.S     |  7 +-
 newlib/libc/machine/arm/strcmp-armv7.S        | 45 ++++++++---
 newlib/libc/machine/arm/strcmp-armv7m.S       | 36 +++++++--
 newlib/libc/machine/arm/strlen-armv7.S        | 53 ++++++++++++-
 newlib/libc/machine/arm/strlen-thumb2-Os.S    | 13 +++-
 11 files changed, 435 insertions(+), 46 deletions(-)
 create mode 100644 newlib/libc/machine/arm/pacbti.h

-- 
2.36.1