[PATCH v5 0/8] Implement assembly cortex-M PACBTI functionality

Hi all,

This respin of the patch series adds the final modifications required to 
patches in response to upstream comments and rebases work on the setjmp 
and longjmp routines onto the fixed arm abi.

Tweaks necessary for correct cfi information generation made to:
* newlib/libc/machine/arm/strcmp-armv7.S
* newlib/libc/machine/arm/memchr.S

Stray comment restored in:
* newlib/libc/machine/arm/memcpy-armv7m.S

Patch rebased, cleaned up and missing BTI landing pad added:
* newlib/libc/machine/arm/setjmp.S


All remaining patches in series remain as in previous iterations.

Thanks,
Victor

------

This patch series modifies hand-written assembly files for Arm
targets, introducing a uniform prologue/epilogue interface,
responsible for pushing/popping registers on function entry and exit,
while 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 combination of parameter macros in
arm-asm.h and 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: aeabi_memmove M-profile PACBTI-enablement
   newlib: libc: aeabi_memset M-profile PACBTI-enablement
   newlib: libc: setjmp M-profile PACBTI-enablement

  .../libc/machine/arm/aeabi_memmove-thumb2.S   |  17 +-
  newlib/libc/machine/arm/aeabi_memset-thumb2.S |  14 +-
  newlib/libc/machine/arm/arm_asm.h             | 441 ++++++++++++++++++
  newlib/libc/machine/arm/memchr.S              |  50 +-
  newlib/libc/machine/arm/memcpy-armv7m.S       |  33 +-
  newlib/libc/machine/arm/setjmp.S              |  39 ++
  newlib/libc/machine/arm/strcmp-arm-tiny.S     |   8 +-
  newlib/libc/machine/arm/strcmp-armv7.S        |  57 ++-
  newlib/libc/machine/arm/strcmp-armv7m.S       |  26 +-
  newlib/libc/machine/arm/strlen-armv7.S        |  17 +-
  newlib/libc/machine/arm/strlen-thumb2-Os.S    |  14 +-
  11 files changed, 656 insertions(+), 60 deletions(-)

-- 
2.36.1