On Tue, Oct 08, 2024 at 03:36:42PM -0700, Deepak Gupta wrote:

Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel
CET [3] and branch target identification (BTI) [4] on arm.
Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control
stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack.

x86 already supports shadow stack for user mode and arm64 support for GCS in
usermode [7] is ongoing.

FWIW the arm64 support is now in -next, including these:

Mark Brown (2):
      mm: Introduce ARCH_HAS_USER_SHADOW_STACK
      prctl: arch-agnostic prctl for shadow stack

shared changes to generic code.