Clean up noarch ipipe queue

Philippe Gerum rpm at xenomai.org
Wed Feb 27 09:13:50 CET 2019


On 2/27/19 7:21 AM, Jan Kiszka wrote:
> Hi Philippe,
> 
> I started to revert the patches in the x86 tree that are touching
> arch/arm. One fragment may be reverted for everyone:
>> --- a/arch/arm/include/asm/arch_timer.h
> +++ b/arch/arm/include/asm/arch_timer.h
> @@ -106,10 +106,6 @@ static inline u32 arch_timer_get_cntkctl(void)
> 
>  static inline void arch_timer_set_cntkctl(u32 cntkctl)
>  {
> -#ifdef CONFIG_IPIPE
> -    /* Enable access to user-space (may not be needed) */
> -    cntkctl |= ARCH_TIMER_USR_PCT_ACCESS_EN;
> -#endif
>      asm volatile("mcr p15, 0, %0, c14, c1, 0" : : "r" (cntkctl));
>  }
> 
> 
> Or are we exploiting user space access?

We are, for reading the timer counter directly via a memory mapping on
arm and arm64. This is a prerequisite for the ipipe_tsc abstraction on
these archs.

> 
> FWIW, I've reverted now these three:
> 
> e219c3bbc14e4d00178b50bb7b992c9817a2aa16
> 259c0c09953d3559618c69f29f5c2aa9fe570a24
> 77361f93e4be1bf23025b01d0d64379a681e11a3
> 

-- 
Philippe.



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