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SubjectRe: [PATCH 1/7] ARM: vdso: Remove dependency with the arch_timer driver internals
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On 08/04/2019 16:49, Marc Zyngier wrote:
> THe VDSO code uses the kernel helper that was originally designed
> to abstract the access between 32 and 64bit systems. It worked so
> far because this function is declared as 'inline'.
>
> As we're about to revamp that part of the code, the VDSO would
> break. Let's fix it by doing what should have been done from
> the start, a proper system register access.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm/include/asm/cp15.h | 2 ++
> arch/arm/vdso/vgettimeofday.c | 5 +++--
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
> index 07e27f212dc7..d2453e2d3f1f 100644
> --- a/arch/arm/include/asm/cp15.h
> +++ b/arch/arm/include/asm/cp15.h
> @@ -68,6 +68,8 @@
> #define BPIALL __ACCESS_CP15(c7, 0, c5, 6)
> #define ICIALLU __ACCESS_CP15(c7, 0, c5, 0)
>
> +#define CNTVCT __ACCESS_CP15_64(1, c14)
> +
> extern unsigned long cr_alignment; /* defined in entry-armv.S */
>
> static inline unsigned long get_cr(void)
> diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c
> index a9dd619c6c29..7bdbf5d5c47d 100644
> --- a/arch/arm/vdso/vgettimeofday.c
> +++ b/arch/arm/vdso/vgettimeofday.c
> @@ -18,9 +18,9 @@
> #include <linux/compiler.h>
> #include <linux/hrtimer.h>
> #include <linux/time.h>
> -#include <asm/arch_timer.h>
> #include <asm/barrier.h>
> #include <asm/bug.h>
> +#include <asm/cp15.h>
> #include <asm/page.h>
> #include <asm/unistd.h>
> #include <asm/vdso_datapage.h>
> @@ -123,7 +123,8 @@ static notrace u64 get_ns(struct vdso_data *vdata)
> u64 cycle_now;
> u64 nsec;
>
> - cycle_now = arch_counter_get_cntvct();
> + isb();
> + cycle_now = read_sysreg(CNTVCT);
>
> cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask;
>
>

Russell, are you OK with this being carried via the arm64 tree? Or would
you prefer me to stick it in your patch system?

Thanks,

M.
--
Jazz is not dead. It just smells funny...

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