linux-kernel - Re: [PATCH v3 08/22] rcu,tracing: Create trace_rcu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200219155828.GF18400@hirez.programming.kicks-ass.net>
Date:   Wed, 19 Feb 2020 16:58:28 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        mingo@...nel.org, joel@...lfernandes.org,
        gregkh@...uxfoundation.org, gustavo@...eddedor.com,
        tglx@...utronix.de, paulmck@...nel.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        luto@...nel.org, tony.luck@...el.com, frederic@...nel.org,
        dan.carpenter@...cle.com, mhiramat@...nel.org
Subject: Re: [PATCH v3 08/22] rcu,tracing: Create trace_rcu_{enter,exit}()

On Wed, Feb 19, 2020 at 10:49:03AM -0500, Steven Rostedt wrote:
> On Wed, 19 Feb 2020 15:47:32 +0100
> Peter Zijlstra <peterz@...radead.org> wrote:

> > These helpers are macros because of header-hell; they're placed here
> > because of the proximity to nmi_{enter,exit{().

^^^^

> > +#define trace_rcu_enter()					\
> > +({								\
> > +	unsigned long state = 0;				\
> > +	if (!rcu_is_watching())	{				\
> > +		rcu_irq_enter_irqsave();			\
> > +		state = 1;					\
> > +	}							\
> > +	state;							\
> > +})
> > +
> > +#define trace_rcu_exit(state)					\
> > +do {								\
> > +	if (state)						\
> > +		rcu_irq_exit_irqsave();				\
> > +} while (0)
> > +
> 
> Is there a reason that these can't be static __always_inline functions?

It can be done, but then we need fwd declarations of those RCU functions
somewhere outside of rcupdate.h. It's all a bit of a mess.