linux-kernel - Re: [PATCH 4/8] asm-generic: add atomic-instrumented.h

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]

Date:   Thu, 30 Mar 2017 11:40:59 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     Dmitry Vyukov <dvyukov@...gle.com>, peterz@...radead.org,
        mingo@...hat.com, akpm@...ux-foundation.org, will.deacon@....com,
        aryabinin@...tuozzo.com, kasan-dev@...glegroups.com,
        linux-kernel@...r.kernel.org, x86@...nel.org, linux-mm@...ck.org
Subject: Re: [PATCH 4/8] asm-generic: add atomic-instrumented.h

On Thu, Mar 30, 2017 at 08:43:39AM +0200, Ingo Molnar wrote:
> 
> * Mark Rutland <mark.rutland@....com> wrote:
> 
> > With some minimal CPP, it can be a lot more manageable:
> > 
> > ----
> > #define INSTR_ATOMIC_XCHG(order)					\
> > static __always_inline int atomic_xchg##order(atomic_t *v, int i)	\
> > {									\
> > 	kasan_check_write(v, sizeof(*v));				\
> > 	arch_atomic_xchg##order(v, i);					\
> > }
> > 
> > #define INSTR_ATOMIC_XCHG()
> > 
> > #ifdef arch_atomic_xchg_relaxed
> > INSTR_ATOMIC_XCHG(_relaxed)
> > #define atomic_xchg_relaxed atomic_xchg_relaxed
> > #endif
> > 
> > #ifdef arch_atomic_xchg_acquire
> > INSTR_ATOMIC_XCHG(_acquire)
> > #define atomic_xchg_acquire atomic_xchg_acquire
> > #endif
> > 
> > #ifdef arch_atomic_xchg_relaxed
> > INSTR_ATOMIC_XCHG(_relaxed)
> > #define atomic_xchg_relaxed atomic_xchg_relaxed
> > #endif
> 
> Yeah, small detail: the third one wants to be _release, right?

Yes; my bad.

> > Is there any objection to some light CPP usage as above for adding the
> > {relaxed,acquire,release} variants?
> 
> No objection from me to that way of writing it, this still looks very readable, 
> and probably more readable than the verbose variants. It's similar in style to 
> linux/atomic.h which has a good balance of C versus CPP.

Great. I'll follow the above pattern when adding the ordering variants.

> What I objected to was the deep nested code generation approach in the original 
> patch.
> 
> CPP is fine in many circumstances, but there's a level of (ab-)use where it 
> becomes counterproductive.

Sure, that makes sense to me.

Thanks,
Mark.