Messages in this thread Patch in this message | | | Date | Wed, 29 Dec 2021 18:42:18 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/MCE/AMD: Allow thresholding interface updates after init |
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On Tue, Dec 07, 2021 at 07:30:28PM +0000, Yazen Ghannam wrote: > Changes to the AMD Thresholding sysfs code prevents sysfs writes from > updating the underlying registers once CPU init is completed, i.e. > "threshold_banks" is set. > > Allow the registers to be updated if the thresholding interface is > already initialized or if in the init path. Use the "set_lvt_off" value > to indicate if running in the init path, since this value is only set > during init. > > Fixes: a037f3ca0ea0 ("x86/mce/amd: Make threshold bank setting hotplug robust") > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
We want that in stable, right?
> --- > arch/x86/kernel/cpu/mce/amd.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c > index 2eadc7c4c902..408c9546ea0b 100644 > --- a/arch/x86/kernel/cpu/mce/amd.c > +++ b/arch/x86/kernel/cpu/mce/amd.c > @@ -400,8 +400,12 @@ static void threshold_restart_bank(void *_tr) > struct thresh_restart *tr = _tr; > u32 hi, lo; > > - /* sysfs write might race against an offline operation */ > - if (this_cpu_read(threshold_banks)) > + /* > + * sysfs write might race against an offline operation. > + * Prevent register writes if threshold_banks are not set and this is > + * not called from the init path as indicated by "set_lvt_off". > + */
So if you convert this text into code, it would read like:
if (!this_cpu_read(threshold_banks) && !tr->set_lvt_off)
which is equivalent to:
> + if (!(this_cpu_read(threshold_banks) || tr->set_lvt_off))
but easier to follow, methinks.
-- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
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