linux-kernel - Re: [RESEND][patch V3 03/23] vmlinux.lds.h: Create section for protection against instrumentation

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Date:   Tue, 24 Mar 2020 13:26:03 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Paul McKenney <paulmck@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Brian Gerst <brgerst@...il.com>,
        Juergen Gross <jgross@...e.com>,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org
Subject: Re: [RESEND][patch V3 03/23] vmlinux.lds.h: Create section for
 protection against instrumentation

Just typos:

On Fri, Mar 20, 2020 at 06:59:59PM +0100, Thomas Gleixner wrote:
> Some code pathes, especially the low level entry code, must be protected

s/pathes/paths/

> against instrumentation for various reasons:
> 
>  - Low level entry code can be a fragile beast, especially on x86.
> 
>  - With NO_HZ_FULL RCU state needs to be established before using it.
> 
> Having a dedicated section for such code allows to validate with tooling
> that no unsafe functions are invoked.
> 
> Add the .noinstr.text section and the noinstr attribute to mark
> functions. noinstr implies notrace. Kprobes will gain a section check
> later.
> 
> Provide also two sets of markers:
> 
>  - instr_begin()/end()
> 
>    This is used to mark code inside in a noinstr function which calls

s/in //

>    into regular instrumentable text section as safe.
> 
>  - noinstr_call_begin()/end()
> 
>    Same as above but used to mark indirect calls which cannot be tracked by
>    tooling and need to be audited manually.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette