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Date:   Mon, 18 Jul 2022 17:19:13 -0700
From:   Joao Moreira <joao@overdrivepizza.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Sami Tolvanen <samitolvanen@google.com>,
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        the arch/x86 maintainers <x86@kernel.org>,
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        Alexei Starovoitov <ast@kernel.org>,
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        Peter Collingbourne <pcc@google.com>
Subject: Re: [patch 00/38] x86/retbleed: Call depth tracking mitigation
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> The extra instruction is likely less of a problem than the extra 
> register used.
> 
FWIIW, per-ABI, R11 is a scratch-reg and should be usable without hard 
consequences in this scenario.

Joao