Re: [patch 02/11] x86/time: Implement clocksource_arch_init()

[Vitaly Kuznetsov]

Thomas Gleixner <tglx@xxxxxxxxxxxxx> writes:

> Runtime validate the VCLOCK_MODE in clocksource::archdata and disable
> VCLOCK if invalid, which disables the VDSO but keeps the system running.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  arch/x86/Kconfig       |    1 +
>  arch/x86/kernel/time.c |   16 ++++++++++++++++
>  2 files changed, 17 insertions(+)
>
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -48,6 +48,7 @@ config X86
>  	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
>  	select ANON_INODES
>  	select ARCH_CLOCKSOURCE_DATA
> +	select ARCH_CLOCKSOURCE_INIT
>  	select ARCH_DISCARD_MEMBLOCK
>  	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
>  	select ARCH_HAS_DEBUG_VIRTUAL
> --- a/arch/x86/kernel/time.c
> +++ b/arch/x86/kernel/time.c
> @@ -10,6 +10,7 @@
>   *
>   */
>
> +#include <linux/clocksource.h>
>  #include <linux/clockchips.h>
>  #include <linux/interrupt.h>
>  #include <linux/irq.h>
> @@ -105,3 +106,18 @@ void __init time_init(void)
>  {
>  	late_time_init = x86_late_time_init;
>  }
> +
> +/*
> + * Sanity check the vdso related archdata content.
> + */
> +void clocksource_arch_init(struct clocksource *cs)
> +{
> +	if (cs->archdata.vclock_mode == VCLOCK_NONE)
> +		return;
> +
> +	if (cs->archdata.vclock_mode >= VCLOCK_MAX) {

It should be '>' as VCLOCK_MAX == VCLOCK_HVCLOCK == 3

> +		pr_warn("clocksource %s registered with invalid vclock_mode %d. Disabling vclock.\n",
> +			cs->name, cs->archdata.vclock_mode);
> +		cs->archdata.vclock_mode = VCLOCK_NONE;
> +	}
> +}

-- 
  Vitaly