From: Thomas Gleixner <tglx@linutronix.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Ingo Molnar <mingo@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will.deacon@arm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
kasan-dev <kasan-dev@googlegroups.com>,
"x86@kernel.org" <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] locking/atomics: don't alias ____ptr
Date: Wed, 28 Jun 2017 17:24:24 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1706281709140.1970@nanos> (raw)
In-Reply-To: <20170628141420.GK5981@leverpostej>
On Wed, 28 Jun 2017, Mark Rutland wrote:
> On Wed, Jun 28, 2017 at 03:54:42PM +0200, Thomas Gleixner wrote:
> > > static inline unsigned long cmpxchg_varsize(void *ptr, unsigned long old,
> > > unsigned long new, int size)
> > > {
> > > switch (size) {
> > > case 1:
> > > case 2:
> > > case 4:
> > > break;
> > > case 8:
> > > if (sizeof(unsigned long) == 8)
> > > break;
> > > default:
> > > BUILD_BUG_ON(1);
> > > }
> > > kasan_check(ptr, size);
> > > return arch_cmpxchg(ptr, old, new);
> > > }
>
> This'll need to re-cast things before the call to arch_cmpxchg(), and we
> can move the check above the switch, as in [2].
Sure, but I rather see that changed to:
1) Create arch_cmpxchg8/16/32/64() inlines first
2) Add that varsize wrapper:
static inline unsigned long cmpxchg_varsize(void *ptr, unsigned long old,
unsigned long new, int size)
{
switch (size) {
case 1:
kasan_check_write(ptr, size);
return arch_cmpxchg8((u8 *)ptr, (u8) old, (u8)new);
case 2:
kasan_check_write(ptr, size);
return arch_cmpxchg16((u16 *)ptr, (u16) old, (u16)new);
case 4:
kasan_check_write(ptr, size);
return arch_cmpxchg32((u32 *)ptr, (u32) old, (u32)new);
case 8:
if (sizeof(unsigned long) == 8) {
kasan_check_write(ptr, size);
return arch_cmpxchg64((u64 *)ptr, (u64) old, (u64)new);
}
default:
BUILD_BUG();
}
}
#define cmpxchg(ptr, o, n) \
({ \
((__typeof__(*(ptr)))cmpxchg_varsize((ptr), (unsigned long)(o), \
(unsigned long)(n), sizeof(*(ptr)))); \
})
Which allows us to create:
static inline u8 cmpxchg8(u8 *ptr, u8 old, u8 new)
{
kasan_check_write(ptr, sizeof(old));
return arch_cmpxchg8(ptr, old, new);
}
and friends as well and later migrate the existing users away from that
untyped macro mess.
And instead of adding
#include <asm/atomic-instrumented.h>
to the architecture code, we rather do
# mv arch/xxx/include/asm/atomic.h mv arch/xxx/include/asm/arch_atomic.h
# echo '#include <asm-generic/atomic.h>' >arch/xxx/include/asm/atomic.h
# mv include/asm-generic/atomic.h include/asm-generic/atomic_up.h
and create a new include/asm-generic/atomic.h
#ifndef __ASM_GENERIC_ATOMIC_H
#define __ASM_GENERIC_ATOMIC_H
#ifdef CONFIG_ATOMIC_INSTRUMENTED_H
#include <asm-generic/atomic_instrumented.h>
#else
#include <asm-generic/atomic_up.h>
#endif
#endif
Thanks,
tglx
next prev parent reply other threads:[~2017-06-28 15:25 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-22 14:14 [PATCH v5 0/4] x86, kasan: add KASAN checks to atomic operations Dmitry Vyukov
[not found] ` <cover.1498140838.git.dvyukov@google.com>
2017-06-22 14:14 ` [PATCH v5 1/4] x86: switch atomic.h to use atomic-instrumented.h Dmitry Vyukov
2017-06-22 21:14 ` Andrew Morton
2017-06-23 8:23 ` Dmitry Vyukov
2017-06-23 8:54 ` Ingo Molnar
2017-06-23 19:00 ` Andrew Morton
2017-06-23 13:59 ` [tip:locking/core] locking/atomic/x86: Switch " tip-bot for Dmitry Vyukov
2017-06-22 14:14 ` [PATCH v5 2/4] kasan: allow kasan_check_read/write() to accept pointers to volatiles Dmitry Vyukov
2017-06-23 14:00 ` [tip:locking/core] kasan: Allow " tip-bot for Dmitry Vyukov
2017-07-26 12:10 ` tip-bot for Dmitry Vyukov
2017-06-22 14:14 ` [PATCH v5 3/4] asm-generic: add KASAN instrumentation to atomic operations Dmitry Vyukov
2017-06-23 14:01 ` [tip:locking/core] locking/atomics, asm-generic: Add " tip-bot for Dmitry Vyukov
2017-06-28 10:02 ` [PATCH] locking/atomics: don't alias ____ptr Sebastian Andrzej Siewior
2017-06-28 10:16 ` Dmitry Vyukov
2017-06-28 11:10 ` Thomas Gleixner
2017-06-28 11:12 ` Dmitry Vyukov
2017-06-28 11:21 ` Thomas Gleixner
2017-06-28 12:45 ` Mark Rutland
2017-06-28 12:24 ` Thomas Gleixner
2017-06-28 12:27 ` Dmitry Vyukov
2017-06-28 13:33 ` Thomas Gleixner
2017-06-28 11:15 ` Andrey Ryabinin
2017-06-28 12:12 ` Sebastian Andrzej Siewior
2017-06-28 13:20 ` Thomas Gleixner
2017-06-28 13:54 ` Thomas Gleixner
2017-06-28 14:14 ` Mark Rutland
2017-06-28 15:24 ` Thomas Gleixner [this message]
2017-06-28 15:54 ` Mark Rutland
2017-06-28 16:56 ` Ingo Molnar
2017-06-28 18:21 ` Thomas Gleixner
2017-06-29 6:47 ` Thomas Gleixner
2017-06-28 14:00 ` Andrey Ryabinin
2017-06-22 14:14 ` [PATCH v5 4/4] asm-generic, x86: add comments for atomic instrumentation Dmitry Vyukov
2017-06-23 14:01 ` [tip:locking/core] locking/atomic/x86, asm-generic: Add " tip-bot for Dmitry Vyukov
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