[PATCH v2] arm64/bti: Disable in kernel BTI when cross section thunks are broken

[Will Deacon]

On Mon, 5 Sep 2022 15:22:55 +0100, Mark Brown wrote:
> GCC does not insert a `bti c` instruction at the beginning of a function
> when it believes that all callers reach the function through a direct
> branch[1]. Unfortunately the logic it uses to determine this is not
> sufficiently robust, for example not taking account of functions being
> placed in different sections which may be loaded separately, so we may
> still see thunks being generated to these functions. If that happens,
> the first instruction in the callee function will result in a Branch
> Target Exception due to the missing landing pad.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64/bti: Disable in kernel BTI when cross section thunks are broken
      https://git.kernel.org/arm64/c/c0a454b9044f

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
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