[lkml]   [2019]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [GIT PULL] Please pull powerpc/linux.git powerpc-5.5-2 tag (topic/kasan-bitops)
On Tue, Dec 10, 2019 at 04:38:54PM +1100, Michael Ellerman wrote:

> Good question, I'll have a look.
> There seems to be confusion about what the type of the bit number is,
> which is leading to sign extension in some cases and not others.


> It looks like the type should be unsigned long?

I'm thinking unsigned makes most sense, I mean, negative bit offsets
should 'work' but that's almost always guaranteed to be an out-of-bound

As to 'long' vs 'int', I'm not sure, 4G bits is a long bitmap. But I
suppose since the bitmap itself is 'unsigned long', we might as well use
'unsigned long' for the bitnr too.

> Documentation/core-api/atomic_ops.rst: void __clear_bit_unlock(unsigned long nr, unsigned long *addr);
> arch/mips/include/asm/bitops.h:static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
> arch/powerpc/include/asm/bitops.h:static inline void arch___clear_bit_unlock(int nr, volatile unsigned long *addr)
> arch/riscv/include/asm/bitops.h:static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
> arch/s390/include/asm/bitops.h:static inline void arch___clear_bit_unlock(unsigned long nr,
> include/asm-generic/bitops/instrumented-lock.h:static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
> include/asm-generic/bitops/lock.h:static inline void __clear_bit_unlock(unsigned int nr,
> So I guess step one is to convert our versions to use unsigned long, so
> we're at least not tripping over that difference when comparing the
> assembly.

Yeah, I'll look at fixing the generic code, bitops/atomic.h and
bitops/non-atomic.h don't even agree on the type of bitnr.

 \ /
  Last update: 2019-12-10 11:16    [W:0.180 / U:0.364 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site