Re: [PATCH 2/2] x86, sched: Fix the undefined reference building error of init_freq_invariance_cppc

[Huang Rui <ray.huang@amd.com>]

On Thu, Jan 06, 2022 at 10:37:59PM +0800, Huang Rui wrote:
> On Thu, Jan 06, 2022 at 08:16:43PM +0800, Borislav Petkov wrote:
> > On Thu, Jan 06, 2022 at 03:43:06PM +0800, Huang Rui wrote:
> > > The init_freq_invariance_cppc function is implemented in smpboot and depends on
> > > CONFIG_SMP.
> > > 
> > >   MODPOST vmlinux.symvers
> > >   MODINFO modules.builtin.modinfo
> > >   GEN     modules.builtin
> > >   LD      .tmp_vmlinux.kallsyms1
> > > ld: drivers/acpi/cppc_acpi.o: in function `acpi_cppc_processor_probe':
> > > /home/ray/brahma3/linux/drivers/acpi/cppc_acpi.c:819: undefined reference to `init_freq_invariance_cppc'
> > > make: *** [Makefile:1161: vmlinux] Error 1
> > > 
> > > See https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flkml%2F484af487-7511-647e-5c5b-33d4429acdec%40infradead.org%2F&data=04%7C01%7Cray.huang%40amd.com%7C4c696d3f23ac4479dda108d9d10e6a53%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637770682133383506%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=9lC2az1xGeYn7fNputkUMsy7PIhmkqW8jdpDUsaWthI%3D&reserved=0.
> > > 
> > > Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems")
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Reported-by: Randy Dunlap <rdunlap@infradead.org>
> > > Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> > > Signed-off-by: Huang Rui <ray.huang@amd.com>
> > > Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > Cc: Borislav Petkov <bp@alien8.de>
> > > Cc: Ingo Molnar <mingo@kernel.org>
> > > Cc: Peter Zijlstra <peterz@infradead.org>
> > > Cc: x86@kernel.org
> > > Cc: stable@vger.kernel.org
> > > ---
> > >  arch/x86/include/asm/topology.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> > > index cc164777e661..2f0b6be8eaab 100644
> > > --- a/arch/x86/include/asm/topology.h
> > > +++ b/arch/x86/include/asm/topology.h
> > > @@ -221,7 +221,7 @@ static inline void arch_set_max_freq_ratio(bool turbo_disabled)
> > >  }
> > >  #endif
> > >  
> > > -#ifdef CONFIG_ACPI_CPPC_LIB
> > > +#if defined(CONFIG_ACPI_CPPC_LIB) && defined(CONFIG_SMP)
> > >  void init_freq_invariance_cppc(void);
> > >  #define init_freq_invariance_cppc init_freq_invariance_cppc
> > >  #endif
> > > -- 
> > 
> > Well, since that function is in smpboot.c then the logic should be that
> > CPPC depends on functionality in smpboot.c for proper operation.
> > 
> > IOW, ACPI_CPPC_LIB should have "depends on CONFIG_SMP" in Kconfig, no?
> > 
> > Instead of adding more ifdeffery around...
> > 
> 
> Hmm, yes, that's fine. I will modify it in V2.
> 

I just thought the CPPC function should be able to work on single core even
SMP is disabled.

Thanks,
Ray