Re: [PATCH 1/5] perf tools: Add get_unaligned_leNN()

[Arnaldo Carvalho de Melo]

Em Thu, Oct 05, 2023 at 04:38:05PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Oct 05, 2023 at 10:04:47PM +0300, Adrian Hunter escreveu:
> > Add get_unaligned_le16(), get_unaligned_le32 and get_unaligned_le64, same
> > as include/asm-generic/unaligned.h.
> > 
> > Use diagnostic pragmas to ignore -Wpacked used by perf build.
> 
> Can we get the tools copy of include/asm-generic/unaligned.h closer and
> have it in check-headers.sh?

And this is not building when cross building to mips, mips64 and mipsel
on debian:experimental:

In file included from util/intel-pt-decoder/intel-pt-pkt-decoder.c:10:
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h: In function 'get_unaligned_le16':
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:13:29: error: packed attribute causes inefficient alignment for 'x' [-Werror=attributes]
   13 |         const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);      \
      |                             ^
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:27:28: note: in expansion of macro '__get_unaligned_t'
   27 |         return le16_to_cpu(__get_unaligned_t(__le16, p));
      |                            ^~~~~~~~~~~~~~~~~
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h: In function 'get_unaligned_le32':
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:13:29: error: packed attribute causes inefficient alignment for 'x' [-Werror=attributes]
   13 |         const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);      \
      |                             ^
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:32:28: note: in expansion of macro '__get_unaligned_t'
   32 |         return le32_to_cpu(__get_unaligned_t(__le32, p));
      |                            ^~~~~~~~~~~~~~~~~


Ditto for some other distros when cross building on ubuntu:18.04

  MKDIR   /tmp/build/perf/util/perf-regs-arch/
In file included from /usr/sparc64-linux-gnu/include/bits/byteswap.h:34:0,
                 from /usr/sparc64-linux-gnu/include/endian.h:60,
                 from util/intel-pt-decoder/intel-pt-pkt-decoder.c:9:
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h: In function 'get_unaligned_le16':
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:13:22: error: packed attribute causes inefficient alignment for 'x' [-Werror=attributes]
  const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
                      ^
/git/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:27:21: note: in expansion of macro '__get_unaligned_t'
  return le16_to_cpu(__get_unaligned_t(__le16, p));
                     ^~~~~~~~~~~~~~~~~

  37    14.17 ubuntu:18.04-x-arm            : FAIL gcc version 7.5.0 (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04)
  38    13.56 ubuntu:18.04-x-arm64          : FAIL gcc version 7.5.0 (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04)
  42    12.70 ubuntu:18.04-x-riscv64        : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
  44    13.95 ubuntu:18.04-x-sh4            : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
  45    13.08 ubuntu:18.04-x-sparc64        : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
 
> - Arnaldo
>  
> > Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > ---
> >  tools/include/asm-generic/unaligned.h | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> > 
> > diff --git a/tools/include/asm-generic/unaligned.h b/tools/include/asm-generic/unaligned.h
> > index 47387c607035..9140bb4e16c6 100644
> > --- a/tools/include/asm-generic/unaligned.h
> > +++ b/tools/include/asm-generic/unaligned.h
> > @@ -6,6 +6,9 @@
> >  #ifndef __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H
> >  #define __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H
> >  
> > +#pragma GCC diagnostic push
> > +#pragma GCC diagnostic ignored "-Wpacked"
> > +
> >  #define __get_unaligned_t(type, ptr) ({						\
> >  	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\
> >  	__pptr->x;								\
> > @@ -19,5 +22,22 @@
> >  #define get_unaligned(ptr)	__get_unaligned_t(typeof(*(ptr)), (ptr))
> >  #define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr))
> >  
> > +static inline u16 get_unaligned_le16(const void *p)
> > +{
> > +	return le16_to_cpu(__get_unaligned_t(__le16, p));
> > +}
> > +
> > +static inline u32 get_unaligned_le32(const void *p)
> > +{
> > +	return le32_to_cpu(__get_unaligned_t(__le32, p));
> > +}
> > +
> > +static inline u64 get_unaligned_le64(const void *p)
> > +{
> > +	return le64_to_cpu(__get_unaligned_t(__le64, p));
> > +}
> > +
> > +#pragma GCC diagnostic pop
> > +
> >  #endif /* __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H */
> >  
> > -- 
> > 2.34.1
> > 
> 
> -- 
> 
> - Arnaldo

-- 

- Arnaldo