svn commit: r291937 - in head: lib/libc/aarch64/sys lib/libc/arm/sys sys/arm/arm sys/arm/include sys/arm64/arm64 sys/arm64/include sys/conf sys/kern

[Ian Lepore]

On Mon, 2015-12-07 at 12:20 +0000, Konstantin Belousov wrote:
> Author: kib
> Date: Mon Dec  7 12:20:26 2015
> New Revision: 291937
> URL: https://svnweb.freebsd.org/changeset/base/291937
> 
> Log:
>   Add support for usermode (vdso-like) gettimeofday(2) and
>   clock_gettime(2) on ARMv7 and ARMv8 systems which have architectural
>   generic timer hardware. It is similar how the RDTSC timer is used in
>   userspace on x86.
>   
>   Fix a permission problem where generic timer access from EL0 (or
>   userspace on v7) was not properly initialized on APs.
>   
>   For ARMv7, mark the stack non-executable. The shared page is added for
>   all arms (including ARMv8 64bit), and the signal trampoline code is
>   moved to the page.
>   
>   Reviewed by:> 	> andrew
>   Discussed with:> 	> emaste, mmel
>   Sponsored by:> 	> The FreeBSD Foundation
>   Differential revision:> 	https://reviews.freebsd.org/D4209

I've just discovered this change breaks buildworld on armv4/5 systems. 
 Those systems don't have the counter hardware that can be read from
userland (they don't have any common timer hardware at all, every
system is different).  Also, they don't support the 'mrrc' instruction,
so the buildworld fails to compile libc.

-- Ian