This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH 6/6] aarch64: Add hp-timing.h
- From: Andreas Schwab <schwab at suse dot de>
- To: Richard Henderson <rth at twiddle dot net>
- Cc: libc-alpha at sourceware dot org, azanella at linux dot vnet dot ibm dot com, davem at davemloft dot net, marcus dot shawcroft at arm dot com
- Date: Mon, 21 Jul 2014 13:41:47 +0200
- Subject: Re: [PATCH 6/6] aarch64: Add hp-timing.h
- Authentication-results: sourceware.org; auth=none
- References: <1403735086-21797-1-git-send-email-rth at twiddle dot net> <1403735086-21797-7-git-send-email-rth at twiddle dot net>
Richard Henderson <rth@twiddle.net> writes:
> +/* Sync the instruction stream, and read from the virtual cycle counter. */
> +#define HP_TIMING_NOW(Var) \
> + __asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (Var))
According to https://bugs.launchpad.net/bugs/1344320 the generic timers
are not part of the kernel-to-userspace contract.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."