On Wed, 28 Jun 2017, Thomas Gleixner wrote:

On Wed, 28 Jun 2017, Mark Rutland wrote:

quoted

On Wed, Jun 28, 2017 at 05:24:24PM +0200, Thomas Gleixner wrote:
Given we're gonig to clean things up, we may as well avoid the backwards
include of <asm-generic/atomic_instrumented.h>, whcih was only there as
a bodge:

For the UP arches we do:
# echo '#include <asm-generic/atomic_up.h>' >arch/xxx/include/asm/atomic.h
# mv include/asm-generic/atomic.h include/asm-generic/atomic_up.h

Then we add a <linux/atomic_instrumented.h>:

#ifndef __LINUX_ATOMIC_INSTRUMENTED_H
#define __LINUX_ATOMIC INSTRUMENTED_H

#include <asm/atomic.h>

#if CONFIG_ATOMIC_INSTRUMENTED_H
<instrumentation>
#endif

#endif /* __LINUX_ATOMIC_ARCH_H */

... and make <linux/atomic.h> incldue that rather than <asm/atomic.h>.

That way the instrumentation's orthogonal to the UP-ness of the arch,
and we can fold any other instrumentation in there, or later move it
directly into <linux/atomic.h>

Sounds like a plan.

Actually we should make it slightly different and make asm-generic/atomic.h
the central point for everything.

It should contain the wrapper macro and the central inlines including the
kasan stuff and include either arch/arch_atomic.h or
asm-generic/atomic_up.h.

That way all potential instrumentation happens in the generic header (which
is a NOP for archs which do not support it) and pull in the appropriate
arch specific or generic UP low level implementations.

Thanks,

	tglx

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