svn commit: r217330 - head/sys/x86/x86

[Bruce Evans]

On Wed, 12 Jan 2011, John Baldwin wrote:

>> Log:
>>   Fix a brain fart.  Since this file is shared between i386 and amd64, a
>>   bus_size_t may be 32 or 64 bits.  Change the bounce_zone alignment field
>>   to explicitly be 32 bits, as I can't really imagine a DMA device that
>>   needs anything close to 2GB alignment of data.
>
> Hmm, we do have devices with 4GB boundaries though.  I think I'd prefer it if
> you instead if you did this:
>
> #if defined(amd64) || defined(PAE)
> #define	SYSCTL_ADD_BUS_SIZE_T		SYSCTL_ADD_UQUAD
> #else
> #define	SYSCTL_ADD_BUS_SIZE_T		SYSCTL_ADD_UINT
> #endif
>
> and then just used SYSCTL_ADD_BUS_SIZE_T() in the code so we could let the
> members in the bounce zone retain the same types passed to
> bus_dma_tag_create().

U_LONG should work on all arches.  malloc(9) still uses u_long instead
of size_t.  This works for scalars even on the recently removed i386's
with 32-bit longs where u_long is larger than size_t, since larger is
a fail-safe direction.  This fails for pointers.  Newer parts of malloc()
and uma are broken unless u_long is the same as uintptr_t, since they
cast pointers to u_long.  This direction is fail-safe too, but gcc warns
about it.

uquad_t should never be used, like unsigned long long.  Similarly for
signed types.  Perhaps it could be removed in sysctl interfaces first.

Bruce