Vitaly Kuznetsov 0733379b51 x86/hyperv: Move TSC reading method to asm/mshyperv.h ... As a preparation to making Hyper-V TSC page suitable for vDSO move the TSC page reading logic to asm/mshyperv.h. While on it, do the following: - Document the reading algorithm. - Simplify the code a bit. - Add explicit READ_ONCE() to not rely on 'volatile'. - Add explicit barriers to prevent re-ordering (we need to read sequence strictly before and after) - Use mul_u64_u64_shr() instead of assembly, gcc generates a single 'mul' instruction on x86_64 anyway. [ tglx: Simplified the loop ] Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: devel@linuxdriverproject.org Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: virtualization@lists.linux-foundation.org Link: http://lkml.kernel.org/r/20170303132142.25595-3-vkuznets@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2017-03-11 14:47:28 +01:00
..
asm	x86/hyperv: Move TSC reading method to asm/mshyperv.h	2017-03-11 14:47:28 +01:00
uapi/asm	x86/boot: Correct setup_header.start_sys name	2017-03-01 11:27:26 +01:00