From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 30 Nov 2012 19:32:54 +0000 Subject: [PATCH 07/10] arm: arch_timer: add arch_counter_enable_user_access In-Reply-To: <1354297568-26366-8-git-send-email-mark.rutland@arm.com> References: <1354297568-26366-1-git-send-email-mark.rutland@arm.com> <1354297568-26366-8-git-send-email-mark.rutland@arm.com> Message-ID: <20121130193254.GA12819@mudshark.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Nov 30, 2012 at 05:46:05PM +0000, Mark Rutland wrote: > Several bits in CNTKCTL reset to 0, including PL0VTEN. For platforms > using the generic timer which wish to have a fast gettimeofday vDSO > implementation, these bits must be set to 1 by the kernel. > > Add an arch_counter_enable_user_access function for this. As we don't > (currently) use the counter from PL0 on arm, the implementation is an > empty stub. > > Signed-off-by: Mark Rutland > Acked-by: Catalin Marinas > Acked-by: Marc Zyngier > --- > arch/arm/include/asm/arch_timer.h | 7 +++++++ > arch/arm/kernel/arch_timer.c | 2 ++ > 2 files changed, 9 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h > index 701f2b7..c50e415 100644 > --- a/arch/arm/include/asm/arch_timer.h > +++ b/arch/arm/include/asm/arch_timer.h > @@ -108,6 +108,13 @@ static inline u64 arch_counter_get_cntvct(void) > return cval; > } > > +static inline void __cpuinit arch_counter_enable_user_access(void) > +{ > + /* > + * Do nothing - the counter is never mapped to userspace threads, > + * so we don't care whether access is enabled or not. > + */ > +} Might be worth explicitly *disabling* userspace access for the time being then (and rename this function to arch_counter_set_user_access?). Will