Thanks, I'll do that.
________________________________________
From: Hans de Goede <hdegoede@xxxxxxxxxx>
Sent: Saturday, May 21, 2022 6:57 AM
To: Travis, Mike; Borislav Petkov; Dave Hansen; Ingo Molnar; Thomas Gleixner; Wahl, Steve; x86@xxxxxxxxxx
Cc: Sivanich, Dimitri; Andy Shevchenko; Darren Hart; H. Peter Anvin; Anderson, Russ; linux-kernel@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] x86/platform/uv: Dont use smp_processor_id while preemptable
Hi Mike,
On 5/20/22 22:37, Mike Travis wrote:
> To avoid a "BUG: using smp_processor_id() in preemptible" debug
> warning message, disable preemption around use of the processor id.
>
> Signed-off-by: Mike Travis <mike.travis@xxxxxxx>
> Reviewed-by: Steve Wahl <steve.wahl@xxxxxxx>
> Reviewed-by: Dimitri Sivanich <dimitri.sivanich@xxxxxxx>
A git blame shows that this code has been around for quite
a while; so presumably this should be backported to some of
the stable kernel series ?
Maybe add an appropriate Cc: stable tag with the range of
kernels this should be added to and/or add a Fixes: tag?
Regards,
Hans
> ---
> arch/x86/platform/uv/uv_time.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c
> index 54663f3e00cb..094190814a28 100644
> --- a/arch/x86/platform/uv/uv_time.c
> +++ b/arch/x86/platform/uv/uv_time.c
> @@ -275,14 +275,17 @@ static int uv_rtc_unset_timer(int cpu, int force)
> */
> static u64 uv_read_rtc(struct clocksource *cs)
> {
> - unsigned long offset;
> + unsigned long offset, time;
> + unsigned int cpu = get_cpu();
>
> if (uv_get_min_hub_revision_id() == 1)
> offset = 0;
> else
> - offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
> + offset = (uv_cpu_blade_processor_id(cpu) * L1_CACHE_BYTES) % PAGE_SIZE;
>
> - return (u64)uv_read_local_mmr(UVH_RTC | offset);
> + time = (u64)uv_read_local_mmr(UVH_RTC | offset);
> + put_cpu();
> + return time;
> }
>
> /*
