Excerpts from Christophe Leroy's message of December 8, 2021 7:38 pm:
>
>
> Le 01/12/2021 à 15:41, Nicholas Piggin a écrit :
>> To avoid any functional changes to radix paths when building with hash
>> MMU support disabled (and CONFIG_PPC_MM_SLICES=n), always define the
>> arch get_unmapped_area calls on 64s platforms.
>>
>> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
>> ---
>> arch/powerpc/include/asm/book3s/64/hash.h | 4 ---
>> arch/powerpc/include/asm/book3s/64/mmu.h | 6 ++++
>> arch/powerpc/mm/hugetlbpage.c | 16 ++++++---
>> arch/powerpc/mm/mmap.c | 40 +++++++++++++++++++----
>> arch/powerpc/mm/slice.c | 20 ------------
>> 5 files changed, 51 insertions(+), 35 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/hash.h
>> b/arch/powerpc/include/asm/book3s/64/hash.h
>> index 674fe0e890dc..a7a0572f3846 100644
>> --- a/arch/powerpc/include/asm/book3s/64/hash.h
>> +++ b/arch/powerpc/include/asm/book3s/64/hash.h
>> @@ -99,10 +99,6 @@
>> * Defines the address of the vmemap area, in its own region on
>> * hash table CPUs.
>> */
>> -#ifdef CONFIG_PPC_MM_SLICES
>> -#define HAVE_ARCH_UNMAPPED_AREA
>> -#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
>> -#endif /* CONFIG_PPC_MM_SLICES */
>>
>> /* PTEIDX nibble */
>> #define _PTEIDX_SECONDARY 0x8
>> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h
>> b/arch/powerpc/include/asm/book3s/64/mmu.h
>> index c02f42d1031e..015d7d972d16 100644
>> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
>> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
>> @@ -4,6 +4,12 @@
>>
>> #include <asm/page.h>
>>
>> +#ifdef CONFIG_HUGETLB_PAGE
>> +#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
>> +#endif
>> +#define HAVE_ARCH_UNMAPPED_AREA
>> +#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
>> +
>> #ifndef __ASSEMBLY__
>> /*
>> * Page size definition
>> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
>> index 82d8b368ca6d..ddead41e2194 100644
>> --- a/arch/powerpc/mm/hugetlbpage.c
>> +++ b/arch/powerpc/mm/hugetlbpage.c
>> @@ -542,20 +542,26 @@ struct page *follow_huge_pd(struct vm_area_struct *vma,
>> return page;
>> }
>>
>> -#ifdef CONFIG_PPC_MM_SLICES
>> +#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
>> +static inline int file_to_psize(struct file *file)
>> +{
>> + struct hstate *hstate = hstate_file(file);
>> + return shift_to_mmu_psize(huge_page_shift(hstate));
>> +}
>> +
>> unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long
>> addr,
>> unsigned long len, unsigned long pgoff,
>> unsigned long flags)
>> {
>> - struct hstate *hstate = hstate_file(file);
>> - int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
>> -
>> #ifdef CONFIG_PPC_RADIX_MMU
>> if (radix_enabled())
>> return radix__hugetlb_get_unmapped_area(file, addr, len,
>> pgoff, flags);
>> #endif
>> - return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
>> +#ifdef CONFIG_PPC_MM_SLICES
>> + return slice_get_unmapped_area(addr, len, flags, file_to_psize(file),
>> 1);
>> +#endif
>> + BUG();
>
> We shouldn't had new instances of BUG().
>
> BUILD_BUG() should do the trick here.
>
>> }
>> #endif
>>
>> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
>> index ae683fdc716c..c475cf810aa8 100644
>> --- a/arch/powerpc/mm/mmap.c
>> +++ b/arch/powerpc/mm/mmap.c
>> @@ -80,6 +80,7 @@ static inline unsigned long mmap_base(unsigned long rnd,
>> return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
>> }
>>
>> +#ifdef HAVE_ARCH_UNMAPPED_AREA
>> #ifdef CONFIG_PPC_RADIX_MMU
>> /*
>> * Same function as generic code used only for radix, because we don't
>> need to overload
>> @@ -181,11 +182,42 @@ radix__arch_get_unmapped_area_topdown(struct file
>> *filp,
>> */
>> return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
>> }
>> +#endif
>> +
>> +unsigned long arch_get_unmapped_area(struct file *filp,
>> + unsigned long addr,
>> + unsigned long len,
>> + unsigned long pgoff,
>> + unsigned long flags)
>> +{
>> +#ifdef CONFIG_PPC_MM_SLICES
>> + return slice_get_unmapped_area(addr, len, flags,
>> +
>> mm_ctx_user_psize(¤t->mm->context), 0);
>> +#else
>> + BUG();
>
> Same.
>
> And the #else isn't needed
>
>> +#endif
>> +}
>> +
>> +unsigned long arch_get_unmapped_area_topdown(struct file *filp,
>> + const unsigned long addr0,
>> + const unsigned long len,
>> + const unsigned long pgoff,
>> + const unsigned long flags)
>> +{
>> +#ifdef CONFIG_PPC_MM_SLICES
>> + return slice_get_unmapped_area(addr0, len, flags,
>> +
>> mm_ctx_user_psize(¤t->mm->context), 1);
>> +#else
>> + BUG();
>
> Same
>
> And the #else isn't needed
Fair enough. I'll see if mpe can squash in an incremental patch.
Thanks,
Nick
