From:   Thomas Gleixner <tglx@linutronix.de>
To:     Nicolas Saenz Julienne <nsaenzju@redhat.com>, mark.rutland@arm.com,
        paulmck@kernel.org
Cc:     rostedt@goodmis.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, rcu@vger.kernel.org,
        peterz@infradead.org, mtosatti@redhat.com, frederic@kernel.org,
        corbet@lwn.net, Nicolas Saenz Julienne <nsaenzju@redhat.com>
Subject: Re: [PATCH v3 1/2] Documentation: Fill the gaps about entry/noinstr
 constraints
In-Reply-To: <20211217105753.892855-1-nsaenzju@redhat.com>
References: <20211217105753.892855-1-nsaenzju@redhat.com>
Date:   Fri, 17 Dec 2021 18:40:25 +0100
Message-ID: <87a6gzcepi.ffs@tglx>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Nicolas,

On Fri, Dec 17 2021 at 11:57, Nicolas Saenz Julienne wrote:
> +Non-instrumentable code - noinstr
> +---------------------------------
> +
> +Most instrumentation facilities depend on RCU, so intrumentation is prohibited
> +for entry code before RCU starts watching and exit code after RCU stops
> +watching. In addition, many architectures must save and restore register state,
> +which means that (for example) a breakpoint in the breakpoint entry code would
> +overwrite the debug registers of the initial breakpoint.
> +
> +Such code must be marked with the 'noinstr' attribute, placing that code into a
> +special section inaccessible to instrumentation and debug facilities. Some
> +functions are partially instrumentable, which is handled by marking them nointr

s/nointr/noinstr/

Thanks for polishing this!

       tglx