lkml.org 
[lkml]   [2024]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v8 12/16] arm64: psci: Ignore DENIED CPUs
From
On 4/26/24 23:51, Jonathan Cameron wrote:
> From: Jean-Philippe Brucker <jean-philippe@linaro.org>
>
> When a CPU is marked as disabled, but online capable in the MADT, PSCI
> applies some firmware policy to control when it can be brought online.
> PSCI returns DENIED to a CPU_ON request if this is not currently
> permitted. The OS can learn the current policy from the _STA enabled bit.
>
> Handle the PSCI DENIED return code gracefully instead of printing an
> error.
>
> Note the alternatives to the PSCI cpu_boot() callback do not
> return -EPERM so the change in smp.c has no affect.
>
> See https://developer.arm.com/documentation/den0022/f/?lang=en page 58.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> [ morse: Rewrote commit message ]
> Signed-off-by: James Morse <james.morse@arm.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
> v8: Note in commit message that the -EPERM guard on the error print
> only affects PSCI as other options never use this error code.
> Should they do so in future, that may well indicate that they
> now support similar refusal to boot.
> ---
> arch/arm64/kernel/psci.c | 2 +-
> arch/arm64/kernel/smp.c | 3 ++-
> 2 files changed, 3 insertions(+), 2 deletions(-)
>

Thanks for the check and clarification that -EPERM is only sensible
to PSCI. With the clarification:

Reviewed-by: Gavin Shan <gshan@redhat.com>

Thanks,
Gavin


\
 
 \ /
  Last update: 2024-05-27 18:08    [W:0.463 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site