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Date:   Thu, 25 Feb 2021 10:59:57 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Masami Hiramatsu <mhiramat@kernel.org>,
        Oleg Nesterov <oleg@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S. Miller" <davem@davemloft.net>, X86 ML <x86@kernel.org>,
        Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: Why do kprobes and uprobes singlestep?
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On Wed, Feb 24, 2021 at 11:45:10AM -0800, Andy Lutomirski wrote:
> I guess I see the point for CALL, JMP and RET, but it seems like we
> could emulate those cases instead fairly easily.

Today, yes. CALL emulation was 'recently' made possible by having #BP
have a stack gap. We have emulation for all 3 those instructions
implemented in asm/text-patching.h, see int3_emulate_$insn().