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Subject: Re: [PATCH 1/3] powerpc/nohash: remove hash related code from nohash
 headers.
To:     Michael Ellerman <mpe@ellerman.id.au>,
        kbuild test robot <lkp@intel.com>
Cc:     kbuild-all@01.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <02633d43f29e1ba01865cd334216dc8efb8b4b11.1524587425.git.christophe.leroy@c-s.fr>
 <201804270438.utPklxgP%fengguang.wu@intel.com>
 <878t8z8yah.fsf@concordia.ellerman.id.au>
From:   Christophe LEROY <christophe.leroy@c-s.fr>
Message-ID: <7b5e3ac5-57d8-d846-247b-422858c01016@c-s.fr>
Date:   Fri, 4 May 2018 14:35:45 +0200
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Le 04/05/2018 à 13:17, Michael Ellerman a écrit :
> kbuild test robot <lkp@intel.com> writes:
> 
>> Hi Christophe,
>>
>> Thank you for the patch! Yet something to improve:
>>
>> [auto build test ERROR on powerpc/next]
>> [also build test ERROR on v4.17-rc2 next-20180426]
>> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>>
>> url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/powerpc-nohash-remove-hash-related-code-from-nohash-headers/20180425-182026
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
>> config: powerpc-ppc64e_defconfig (attached as .config)
>> compiler: powerpc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
>> reproduce:
>>          wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>          chmod +x ~/bin/make.cross
>>          # save the attached .config to linux build tree
>>          make.cross ARCH=powerpc
>>
>> All errors (new ones prefixed by >>):
>>
>>     In file included from arch/powerpc/include/asm/nohash/pgtable.h:6:0,
>>                      from arch/powerpc/include/asm/pgtable.h:19,
>>                      from include/linux/memremap.h:8,
>>                      from include/linux/mm.h:27,
>>                      from include/linux/mman.h:5,
>>                      from arch/powerpc/kernel/asm-offsets.c:22:
>>     arch/powerpc/include/asm/nohash/64/pgtable.h: In function '__ptep_test_and_clear_young':
>>>> arch/powerpc/include/asm/nohash/64/pgtable.h:214:6: error: implicit declaration of function 'pte_young'; did you mean 'pte_pud'? [-Werror=implicit-function-declaration]
>>       if (pte_young(*ptep))
>>           ^~~~~~~~~
>>           pte_pud
> 
> Urk.
> 
> There's a circular dependency here.
> 
> I fixed it with the patch below, which seems to be the least worst
> solution. Possibly we can clean things up further in future.

Oops, I just sent you a new version of the patch not using pte_young() 
anymore. I'll let you decide what to do.

Christophe

> 
> cheers
> 
> diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
> index 140f8e74b478..987a658b18e1 100644
> --- a/arch/powerpc/include/asm/nohash/32/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
> @@ -267,6 +267,11 @@ static inline void __ptep_set_access_flags(struct mm_struct *mm,
>   	pte_update(ptep, clr, set);
>   }
>   
> +static inline int pte_young(pte_t pte)
> +{
> +	return pte_val(pte) & _PAGE_ACCESSED;
> +}
> +
>   #define __HAVE_ARCH_PTE_SAME
>   #define pte_same(A,B)	((pte_val(A) ^ pte_val(B)) == 0)
>   
> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
> index e8de7cb4d3fb..6ac8381f4c7a 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
> @@ -204,6 +204,11 @@ static inline unsigned long pte_update(struct mm_struct *mm,
>   	return old;
>   }
>   
> +static inline int pte_young(pte_t pte)
> +{
> +	return pte_val(pte) & _PAGE_ACCESSED;
> +}
> +
>   static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
>   					      unsigned long addr, pte_t *ptep)
>   {
> diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
> index 077472640b35..2160be2e4339 100644
> --- a/arch/powerpc/include/asm/nohash/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/pgtable.h
> @@ -17,7 +17,6 @@ static inline int pte_write(pte_t pte)
>   }
>   static inline int pte_read(pte_t pte)		{ return 1; }
>   static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
> -static inline int pte_young(pte_t pte)		{ return pte_val(pte) & _PAGE_ACCESSED; }
>   static inline int pte_special(pte_t pte)	{ return pte_val(pte) & _PAGE_SPECIAL; }
>   static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
>   static inline pgprot_t pte_pgprot(pte_t pte)	{ return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }
>