Messages in this thread | | | Date | Wed, 29 Mar 2017 07:47:26 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH V4 1/2] x86/msr: expose msr_flip_bit function |
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On Tue, 28 Mar 2017, kan.liang@intel.com wrote: > From: Kan Liang <Kan.liang@intel.com> > > There is no exported kernel interfaces which can flip a MSR bit. It has > to do read-modify-write operation on the MSR through rd/wrmsr* > interfaces. But the method is not atomic. > > There is already __flip_bit support. Just rename and expose it.
This function is not atomic either. Protection has to be provided by the caller.
> -static inline int __flip_bit(u32 msr, u8 bit, bool set) > +int msr_flip_bit(u32 msr, u8 bit, bool set) > { > struct msr m, m1; > int err = -EINVAL; > @@ -85,6 +85,7 @@ static inline int __flip_bit(u32 msr, u8 bit, bool set) > > return 1; > } > +EXPORT_SYMBOL_GPL(msr_flip_bit);
That export is not required. The call site is always built in.
Thanks,
tglx
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