Messages in this thread | | | Date | Mon, 4 Mar 2019 11:15:12 -0800 | From | Fenghua Yu <> | Subject | Re: [PATCH v4 04/17] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access |
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On Mon, Mar 04, 2019 at 10:52:19AM -0800, Dave Hansen wrote: > On 3/1/19 6:44 PM, Fenghua Yu wrote: > > diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h > > index 33051436c864..eb8ae701ef65 100644 > > --- a/arch/x86/include/asm/processor.h > > +++ b/arch/x86/include/asm/processor.h > > @@ -93,7 +93,9 @@ struct cpuinfo_x86 { > > __u32 extended_cpuid_level; > > /* Maximum supported CPUID level, -1=no CPUID: */ > > int cpuid_level; > > - __u32 x86_capability[NCAPINTS + NBUGINTS]; > > + /* Unsigned long alignment to avoid split lock in atomic bitmap ops */ > > + __u32 x86_capability[NCAPINTS + NBUGINTS] > > + __aligned(sizeof(unsigned long)); > > I think this also warrants a comment in the changelog about the > alignment of 'struct cpuinfo_x86'.
How about add "Depending on the starting address where GCC generates for data of struct cpuinfo_x86, x86_capability[] may or may not align to unsigned long...."?
Thanks.
-Fenghua
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