[PATCH] Support HWCAPs for MIPS

[Joseph S. Myers]

On Tue, 14 Oct 2014, Matthew Fortune wrote:

> +#define HWCAP_MIPS_R6	0x00000001
> +#define HWCAP_MIPS_MSA	0x00000002

HWCAP values are assigned by the kernel; they are not ELF-level interfaces 
but interfaces between the kernel and userspace; we normally add new 
values once there's been a kernel.org release with those values in, as 
part of the routine review of new kernel releases for any new interfaces 
of relevance to glibc.  In this case, I don't see these values in 
kernel.org git at all, so it seems premature to add them to glibc; please 
resubmit this patch once the values have been assigned in the kernel (or 
if one value is assigned before the other, it's fine to submit a patch 
with just that value as soon as it's been assigned).

If I've missed the definition of these values in the kernel, please give 
more details of where they are defined 
(git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git rather 
than any other, e.g. architecture-specific, git tree).

Being Linux-specific, I think the right location for these files is 
sysdeps/unix/sysv/linux/mips/ similar to ARM (although other architectures 
putting such OS-specific definitions in OS-independent files doesn't cause 
practical problems in the absence of other-OS ports for those 
architectures).

If you want to get other patches depending on HWCAP tests in some way into 
glibc before the HWCAP values are allocated in the kernel, I advise 
setting up the glibc code to hardcode whatever it would do with an old 
kernel that never sets a nonzero HWCAP, and then adding support for 
handling new kernel features later when the values are allocated.

-- 
Joseph S. Myers
joseph@codesourcery.com