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SubjectRe: [PATCH] x86/build: Move '-mindirect-branch-cs-prefix' out of GCC-only block
On Thu, Aug 18, 2022 at 09:45:39AM +0200, Peter Zijlstra wrote:

> The thing to do is boot with (warning, *very* verbose):
>
> "spectre_v2=retpoline,lfence debug-alternative"
>
> and observe that the retpoline sites all replace:
>
> "cs call __x86_indirect_thunk_r11" (6 bytes)
>
> with:
>
> "lfence; jmp *%r11" (6 bytes)

^^ call, ofc, unless the original was jmp then jmp...

/me goes get more morning juice in an attempt to wake up.

>
>
> This being clang, you'll ofcourse still have a few weird:
>
> "Jcc.d32 __x86_indirect_thunk_r11"
>
> sites that will not be able to be replaced, but there's nothing I can do
> about that other than to continue to encourage y'all to stop emitting
> them ;-)

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