svn commit: r233419 - head/sys/x86/include

[Jaakko Heinonen]

Hi,

On 2012-03-24, Dimitry Andric wrote:
>   Fix the following clang warning in sys/dev/dcons/dcons.c, caused by the
>   recent changes in sys/x86/include/endian.h:
>   
>     sys/dev/dcons/dcons.c:190:15: error: implicit conversion from '__uint32_t' (aka 'unsigned int') to '__uint16_t' (aka 'unsigned short') changes value from 1684238190 to 28526 [-Werror,-Wconstant-conversion]
>   	  buf->magic = ntohl(DCONS_MAGIC);
>   		       ^~~~~~~~~~~~~~~~~~
>     sys/sys/param.h:306:18: note: expanded from:
>     #define ntohl(x)        __ntohl(x)
>   			  ^
>     ./x86/endian.h:128:20: note: expanded from:
>     #define __ntohl(x)      __bswap32(x)
>   			  ^
>     ./x86/endian.h:78:20: note: expanded from:
>   	      __bswap32_gen((__uint32_t)(x)) : __bswap32_var(x))
>   			    ^
>     ./x86/endian.h:68:26: note: expanded from:
>   	  (((__uint32_t)__bswap16(x) << 16) | __bswap16((x) >> 16))
>   				  ^
>     ./x86/endian.h:75:53: note: expanded from:
>   	      __bswap16_gen((__uint16_t)(x)) : __bswap16_var(x)))
>   					       ~~~~~~~~~~~~~ ^
>   
>   This is because the __bswapXX_gen() macros (for x86) call the regular
>   __bswapXX() macros.  Since the __bswapXX_gen() variants are only called
>   when their arguments are constant, there is no need to do that constancy
>   check recursively.  Also, it causes the above error with clang.
>   
>   Fix it by calling __bswap16_gen() from __bswap32_gen(), and similarly,
>   __bswap32_gen() from  __bswap64_gen().
>   
>   While here, add extra parentheses around the __bswap16_gen() macro
>   expansion, to prevent unexpected side effects.
> 
> Modified:
>   head/sys/x86/include/endian.h

This commit seems to have broken kernel dumping for me. I always get:

# savecore
savecore: error reading first dump header at offset 4143647740 in /dev/ada0s1b: Invalid argument

The offset varies.

FreeBSD x 10.0-CURRENT FreeBSD 10.0-CURRENT #826 r233419M: Thu Mar 29 15:46:12 EEST 2012 x at x:X  i386

Dumping works with r233418.

-- 
Jaakko