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Subject: Re: [PATCH v5 09/11] hugetlb: Introduce generic version of
 huge_ptep_set_wrprotect
From:   Alex Ghiti <alex@ghiti.fr>
To:     Michael Ellerman <mpe@ellerman.id.au>, linux-mm@kvack.org,
        mike.kravetz@oracle.com, linux@armlinux.org.uk,
        catalin.marinas@arm.com, will.deacon@arm.com, tony.luck@intel.com,
        fenghua.yu@intel.com, ralf@linux-mips.org, paul.burton@mips.com,
        jhogan@kernel.org, jejb@parisc-linux.org, deller@gmx.de,
        benh@kernel.crashing.org, ysato@users.sourceforge.jp,
        dalias@libc.org, davem@davemloft.net, tglx@linutronix.de,
        mingo@redhat.com, hpa@zytor.com, x86@kernel.org, arnd@arndb.de,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-ia64@vger.kernel.org, linux-mips@linux-mips.org,
        linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
        linux-arch@vger.kernel.org,
        "aneesh.kumar@linux.ibm.com" <aneesh.kumar@linux.ibm.com>
References: <20180731060155.16915-1-alex@ghiti.fr>
 <20180731060155.16915-10-alex@ghiti.fr>
 <87h8kfhg7o.fsf@concordia.ellerman.id.au>
 <6acb1389-6998-bafb-cf69-174fd522c04c@ghiti.fr>
Message-ID: <90bf556f-144d-24b8-d2f6-70fee4a30559@ghiti.fr>
Date:   Fri, 3 Aug 2018 05:24:29 +0000
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Ok, I tried every defconfig available:

- for the nohash/32, I found that I could use mpc885_ads_defconfig and I 
activated HUGETLBFS.
I removed the definition of huge_ptep_set_wrprotect from 
nohash/32/pgtable.h, add an #error in
include/asm-generic/hugetlb.h right before the generic definition of 
huge_ptep_set_wrprotect,
and fell onto it at compile-time:
=> I'm pretty confident then that removing the definition of 
huge_ptep_set_wrprotect does not
break anythingin this case.

- regardind book3s/32, I did not find any defconfig with 
CONFIG_PPC_BOOK3S_32, CONFIG_PPC32
allowing to enable huge page support (ie CONFIG_SYS_SUPPORTS_HUGETLBFS)
=> Do you have a defconfig that would allow me to try the same as above ?

Thanks,

Alex


On 07/31/2018 11:17 AM, Alexandre Ghiti wrote:
>
> On 07/31/2018 12:06 PM, Michael Ellerman wrote:
>> Alexandre Ghiti <alex@ghiti.fr> writes:
>>
>>> arm, ia64, mips, sh, x86 architectures use the same version
>>> of huge_ptep_set_wrprotect, so move this generic implementation into
>>> asm-generic/hugetlb.h.
>>> Note: powerpc uses twice for book3s/32 and nohash/32 the same 
>>> version as
>>> the above architectures, but the modification was not straightforward
>>> and hence has not been done.
>> Do you remember what the problem was there?
>>
>> It looks like you should just be able to drop them like the others. I
>> assume there's some header spaghetti that causes problems though?
>
> Yes, the header spaghetti frightened me a bit. Maybe I should have 
> tried harder: I can try to remove them and find the right defconfigs 
> to compile both to begin with. And to guarantee the functionality is 
> preserved, can I use the testsuite of libhugetlbfs with qemu ?
>
> Alex
>
>>
>> cheers
>>
>>
>>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
>>> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
>>> ---
>>>   arch/arm/include/asm/hugetlb-3level.h        | 6 ------
>>>   arch/arm64/include/asm/hugetlb.h             | 1 +
>>>   arch/ia64/include/asm/hugetlb.h              | 6 ------
>>>   arch/mips/include/asm/hugetlb.h              | 6 ------
>>>   arch/parisc/include/asm/hugetlb.h            | 1 +
>>>   arch/powerpc/include/asm/book3s/32/pgtable.h | 2 ++
>>>   arch/powerpc/include/asm/book3s/64/pgtable.h | 1 +
>>>   arch/powerpc/include/asm/nohash/32/pgtable.h | 2 ++
>>>   arch/powerpc/include/asm/nohash/64/pgtable.h | 1 +
>>>   arch/sh/include/asm/hugetlb.h                | 6 ------
>>>   arch/sparc/include/asm/hugetlb.h             | 1 +
>>>   arch/x86/include/asm/hugetlb.h               | 6 ------
>>>   include/asm-generic/hugetlb.h                | 8 ++++++++
>>>   13 files changed, 17 insertions(+), 30 deletions(-)
>>>
>>> diff --git a/arch/arm/include/asm/hugetlb-3level.h 
>>> b/arch/arm/include/asm/hugetlb-3level.h
>>> index b897541520ef..8247cd6a2ac6 100644
>>> --- a/arch/arm/include/asm/hugetlb-3level.h
>>> +++ b/arch/arm/include/asm/hugetlb-3level.h
>>> @@ -37,12 +37,6 @@ static inline pte_t huge_ptep_get(pte_t *ptep)
>>>       return retval;
>>>   }
>>>   -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> -                       unsigned long addr, pte_t *ptep)
>>> -{
>>> -    ptep_set_wrprotect(mm, addr, ptep);
>>> -}
>>> -
>>>   static inline int huge_ptep_set_access_flags(struct vm_area_struct 
>>> *vma,
>>>                            unsigned long addr, pte_t *ptep,
>>>                            pte_t pte, int dirty)
>>> diff --git a/arch/arm64/include/asm/hugetlb.h 
>>> b/arch/arm64/include/asm/hugetlb.h
>>> index 3e7f6e69b28d..f4f69ae5466e 100644
>>> --- a/arch/arm64/include/asm/hugetlb.h
>>> +++ b/arch/arm64/include/asm/hugetlb.h
>>> @@ -48,6 +48,7 @@ extern int huge_ptep_set_access_flags(struct 
>>> vm_area_struct *vma,
>>>   #define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
>>>   extern pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
>>>                        unsigned long addr, pte_t *ptep);
>>> +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                       unsigned long addr, pte_t *ptep);
>>>   #define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
>>> diff --git a/arch/ia64/include/asm/hugetlb.h 
>>> b/arch/ia64/include/asm/hugetlb.h
>>> index cbe296271030..49d1f7949f3a 100644
>>> --- a/arch/ia64/include/asm/hugetlb.h
>>> +++ b/arch/ia64/include/asm/hugetlb.h
>>> @@ -27,12 +27,6 @@ static inline void huge_ptep_clear_flush(struct 
>>> vm_area_struct *vma,
>>>   {
>>>   }
>>>   -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> -                       unsigned long addr, pte_t *ptep)
>>> -{
>>> -    ptep_set_wrprotect(mm, addr, ptep);
>>> -}
>>> -
>>>   static inline int huge_ptep_set_access_flags(struct vm_area_struct 
>>> *vma,
>>>                            unsigned long addr, pte_t *ptep,
>>>                            pte_t pte, int dirty)
>>> diff --git a/arch/mips/include/asm/hugetlb.h 
>>> b/arch/mips/include/asm/hugetlb.h
>>> index 6ff2531cfb1d..3dcf5debf8c4 100644
>>> --- a/arch/mips/include/asm/hugetlb.h
>>> +++ b/arch/mips/include/asm/hugetlb.h
>>> @@ -63,12 +63,6 @@ static inline int huge_pte_none(pte_t pte)
>>>       return !val || (val == (unsigned long)invalid_pte_table);
>>>   }
>>>   -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> -                       unsigned long addr, pte_t *ptep)
>>> -{
>>> -    ptep_set_wrprotect(mm, addr, ptep);
>>> -}
>>> -
>>>   static inline int huge_ptep_set_access_flags(struct vm_area_struct 
>>> *vma,
>>>                            unsigned long addr,
>>>                            pte_t *ptep, pte_t pte,
>>> diff --git a/arch/parisc/include/asm/hugetlb.h 
>>> b/arch/parisc/include/asm/hugetlb.h
>>> index fb7e0fd858a3..9c3950ca2974 100644
>>> --- a/arch/parisc/include/asm/hugetlb.h
>>> +++ b/arch/parisc/include/asm/hugetlb.h
>>> @@ -39,6 +39,7 @@ static inline void huge_ptep_clear_flush(struct 
>>> vm_area_struct *vma,
>>>   {
>>>   }
>>>   +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep);
>>>   diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h 
>>> b/arch/powerpc/include/asm/book3s/32/pgtable.h
>>> index 02f5acd7ccc4..d2cd1d0226e9 100644
>>> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h
>>> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
>>> @@ -228,6 +228,8 @@ static inline void ptep_set_wrprotect(struct 
>>> mm_struct *mm, unsigned long addr,
>>>   {
>>>       pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), _PAGE_RO);
>>>   }
>>> +
>>> +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep)
>>>   {
>>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
>>> b/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> index 42aafba7a308..7d957f7c47cd 100644
>>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> @@ -451,6 +451,7 @@ static inline void ptep_set_wrprotect(struct 
>>> mm_struct *mm, unsigned long addr,
>>>           pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 0);
>>>   }
>>>   +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep)
>>>   {
>>> diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h 
>>> b/arch/powerpc/include/asm/nohash/32/pgtable.h
>>> index 7c46a98cc7f4..f39e200d9591 100644
>>> --- a/arch/powerpc/include/asm/nohash/32/pgtable.h
>>> +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
>>> @@ -249,6 +249,8 @@ static inline void ptep_set_wrprotect(struct 
>>> mm_struct *mm, unsigned long addr,
>>>   {
>>>       pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), _PAGE_RO);
>>>   }
>>> +
>>> +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep)
>>>   {
>>> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h 
>>> b/arch/powerpc/include/asm/nohash/64/pgtable.h
>>> index dd0c7236208f..69fbf7e9b4db 100644
>>> --- a/arch/powerpc/include/asm/nohash/64/pgtable.h
>>> +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
>>> @@ -238,6 +238,7 @@ static inline void ptep_set_wrprotect(struct 
>>> mm_struct *mm, unsigned long addr,
>>>       pte_update(mm, addr, ptep, _PAGE_RW, 0, 0);
>>>   }
>>>   +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep)
>>>   {
>>> diff --git a/arch/sh/include/asm/hugetlb.h 
>>> b/arch/sh/include/asm/hugetlb.h
>>> index f1bbd255ee43..8df4004977b9 100644
>>> --- a/arch/sh/include/asm/hugetlb.h
>>> +++ b/arch/sh/include/asm/hugetlb.h
>>> @@ -32,12 +32,6 @@ static inline void huge_ptep_clear_flush(struct 
>>> vm_area_struct *vma,
>>>   {
>>>   }
>>>   -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> -                       unsigned long addr, pte_t *ptep)
>>> -{
>>> -    ptep_set_wrprotect(mm, addr, ptep);
>>> -}
>>> -
>>>   static inline int huge_ptep_set_access_flags(struct vm_area_struct 
>>> *vma,
>>>                            unsigned long addr, pte_t *ptep,
>>>                            pte_t pte, int dirty)
>>> diff --git a/arch/sparc/include/asm/hugetlb.h 
>>> b/arch/sparc/include/asm/hugetlb.h
>>> index 2101ea217f33..c41754a113f3 100644
>>> --- a/arch/sparc/include/asm/hugetlb.h
>>> +++ b/arch/sparc/include/asm/hugetlb.h
>>> @@ -32,6 +32,7 @@ static inline void huge_ptep_clear_flush(struct 
>>> vm_area_struct *vma,
>>>   {
>>>   }
>>>   +#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>>   static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>>                          unsigned long addr, pte_t *ptep)
>>>   {
>>> diff --git a/arch/x86/include/asm/hugetlb.h 
>>> b/arch/x86/include/asm/hugetlb.h
>>> index 59c056adb3c9..a3f781f7a264 100644
>>> --- a/arch/x86/include/asm/hugetlb.h
>>> +++ b/arch/x86/include/asm/hugetlb.h
>>> @@ -13,12 +13,6 @@ static inline int is_hugepage_only_range(struct 
>>> mm_struct *mm,
>>>       return 0;
>>>   }
>>>   -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> -                       unsigned long addr, pte_t *ptep)
>>> -{
>>> -    ptep_set_wrprotect(mm, addr, ptep);
>>> -}
>>> -
>>>   static inline int huge_ptep_set_access_flags(struct vm_area_struct 
>>> *vma,
>>>                            unsigned long addr, pte_t *ptep,
>>>                            pte_t pte, int dirty)
>>> diff --git a/include/asm-generic/hugetlb.h 
>>> b/include/asm-generic/hugetlb.h
>>> index 6c0c8b0c71e0..9b9039845278 100644
>>> --- a/include/asm-generic/hugetlb.h
>>> +++ b/include/asm-generic/hugetlb.h
>>> @@ -102,4 +102,12 @@ static inline int prepare_hugepage_range(struct 
>>> file *file,
>>>   }
>>>   #endif
>>>   +#ifndef __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
>>> +static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>>> +        unsigned long addr, pte_t *ptep)
>>> +{
>>> +    ptep_set_wrprotect(mm, addr, ptep);
>>> +}
>>> +#endif
>>> +
>>>   #endif /* _ASM_GENERIC_HUGETLB_H */
>>> -- 
>>> 2.16.2
>