[PATCH] D72215: [AArch64] Add function attribute "patchable-function-entry" to add NOPs at function entry

[Mark Rutland via Phabricator via llvm-commits]

mrutland added a comment.

> The N,M form (function entry points before the Mth NOP) is
>  currently only used by parisc.

As a heads-up, I have rough plans to use the N,M form for the arm64 Linux kernel in the near future. We may need this so that we can allocate trampolines or literal pools next too patch sites for live-patching and/or large test kernels.

> This patch adds N,0 support to AArch64 codegen. N is represented as the
>  function attribute "patchable-function-entry". We will use a different
>  function attribute for M, if we decide to implement it.

Other than the interaction with BTI, is implementing the full N,M form difficult today?

I'll poke the GCC folk w.r.t. the BTI issues.


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D72215