Re: [PATCH v10 10/13] powerpc/mm: Move get_unmapped_area functions to slice.c

Christophe Leroy
2022-05-23T15:18:21Z

Le 23/05/2022 à 14:27, Laurent Dufour a écrit :
> On 09/04/2022, 19:17:34, Christophe Leroy wrote:
>> hugetlb_get_unmapped_area() is now identical to the
>> generic version if only RADIX is enabled, so move it
>> to slice.c and let it fallback on the generic one
>> when HASH MMU is not compiled in.
>>
>> Do the same with arch_get_unmapped_area() and
>> arch_get_unmapped_area_topdown().
>
> This breaks the build when CONFIG_PPC_64S_HASH_MMU is not set.
>
> The root cause is that arch/powerpc/mm/book3s64/slice.c is not built if
> !CONFIG_PPC_64S_HASH_MMU.
> The commit f693d38d9468 (powerpc/mm: Remove CONFIG_PPC_MM_SLICES,
> 2022-04-09) builds slice.c only if CONFIG_PPC_64S_HASH_MMU.

I think the root cause is slice.h is being included allthough
!CONFIG_PPC_64S_HASH_MMU, which leads to HAVE_ARCH_UNMAPPED_AREA and
HAVE_ARCH_UNMAPPED_AREA_TOPDOWN being defined while they shouldn't

Wondering why I didn't see that before.

slice.h gets included via asm/book3s/64/mmu-hash.h

I was able to build microwatt_defconfig with the following changes:

diff --git a/arch/powerpc/include/asm/book3s/64/slice.h
b/arch/powerpc/include/asm/book3s/64/slice.h
index b8eb4ad271b9..5fbe18544cbd 100644
--- a/arch/powerpc/include/asm/book3s/64/slice.h
+++ b/arch/powerpc/include/asm/book3s/64/slice.h
@@ -4,11 +4,13 @@

#ifndef __ASSEMBLY__

+#ifdef CONFIG_PPC_64S_HASH_MMU
#ifdef CONFIG_HUGETLB_PAGE
#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
#endif
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#endif

#define SLICE_LOW_SHIFT 28
#define SLICE_LOW_TOP (0x100000000ul)
diff --git a/arch/powerpc/sysdev/xics/ics-native.c
b/arch/powerpc/sysdev/xics/ics-native.c
index e33b77da861e..112c8a1e8159 100644
--- a/arch/powerpc/sysdev/xics/ics-native.c
+++ b/arch/powerpc/sysdev/xics/ics-native.c
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/spinlock.h>
#include <linux/msi.h>
#include <linux/list.h>

>
> I'm wondering if these functions have to be moved in slice.c
>
> Attached is the config file I used.
>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>> arch/powerpc/include/asm/book3s/64/mmu.h | 6 ----
>> arch/powerpc/include/asm/book3s/64/slice.h | 6 ++++
>> arch/powerpc/mm/book3s64/slice.c | 42 ++++++++++++++++++++++
>> arch/powerpc/mm/hugetlbpage.c | 21 -----------
>> arch/powerpc/mm/mmap.c | 36 -------------------
>> 5 files changed, 48 insertions(+), 63 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
>> index 006cbec70ffe..570a4960cf17 100644
>> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
>> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
>> @@ -4,12 +4,6 @@
>>
>> #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/include/asm/book3s/64/slice.h b/arch/powerpc/include/asm/book3s/64/slice.h
>> index 5b0f7105bc8b..b8eb4ad271b9 100644
>> --- a/arch/powerpc/include/asm/book3s/64/slice.h
>> +++ b/arch/powerpc/include/asm/book3s/64/slice.h
>> @@ -4,6 +4,12 @@
>>
>> #ifndef __ASSEMBLY__
>>
>> +#ifdef CONFIG_HUGETLB_PAGE
>> +#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
>> +#endif
>> +#define HAVE_ARCH_UNMAPPED_AREA
>> +#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
>> +
>> #define SLICE_LOW_SHIFT 28
>> #define SLICE_LOW_TOP (0x100000000ul)
>> #define SLICE_NUM_LOW (SLICE_LOW_TOP >> SLICE_LOW_SHIFT)
>> diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
>> index e4382713746d..03681042b807 100644
>> --- a/arch/powerpc/mm/book3s64/slice.c
>> +++ b/arch/powerpc/mm/book3s64/slice.c
>> @@ -639,6 +639,32 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
>> }
>> EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
>>
>> +unsigned long arch_get_unmapped_area(struct file *filp,
>> + unsigned long addr,
>> + unsigned long len,
>> + unsigned long pgoff,
>> + unsigned long flags)
>> +{
>> + if (radix_enabled())
>> + return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
>> +
>> + return slice_get_unmapped_area(addr, len, flags,
>> + mm_ctx_user_psize(&current->mm->context), 0);
>> +}
>> +
>> +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)
>> +{
>> + if (radix_enabled())
>> + return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
>> +
>> + return slice_get_unmapped_area(addr0, len, flags,
>> + mm_ctx_user_psize(&current->mm->context), 1);
>> +}
>> +
>> unsigned int notrace get_slice_psize(struct mm_struct *mm, unsigned long addr)
>> {
>> unsigned char *psizes;
>> @@ -766,4 +792,20 @@ unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
>>
>> return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start));
>> }
>> +
>> +static 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)
>> +{
>> + if (radix_enabled())
>> + return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
>> +
>> + return slice_get_unmapped_area(addr, len, flags, file_to_psize(file), 1);
>> +}
>> #endif
>> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
>> index a87c886042e9..b282af39fcf6 100644
>> --- a/arch/powerpc/mm/hugetlbpage.c
>> +++ b/arch/powerpc/mm/hugetlbpage.c
>> @@ -542,27 +542,6 @@ struct page *follow_huge_pd(struct vm_area_struct *vma,
>> return page;
>> }
>>
>> -#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)
>> -{
>> - if (radix_enabled())
>> - return generic_hugetlb_get_unmapped_area(file, addr, len,
>> - pgoff, flags);
>> -#ifdef CONFIG_PPC_64S_HASH_MMU
>> - return slice_get_unmapped_area(addr, len, flags, file_to_psize(file), 1);
>> -#endif
>> - BUG();
>> -}
>> -#endif
>> -
>> bool __init arch_hugetlb_valid_size(unsigned long size)
>> {
>> int shift = __ffs(size);
>> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
>> index 46781d0103d1..5972d619d274 100644
>> --- a/arch/powerpc/mm/mmap.c
>> +++ b/arch/powerpc/mm/mmap.c
>> @@ -80,42 +80,6 @@ static inline unsigned long mmap_base(unsigned long rnd,
>> return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
>> }
>>
>> -#ifdef HAVE_ARCH_UNMAPPED_AREA
>> -unsigned long arch_get_unmapped_area(struct file *filp,
>> - unsigned long addr,
>> - unsigned long len,
>> - unsigned long pgoff,
>> - unsigned long flags)
>> -{
>> - if (radix_enabled())
>> - return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
>> -
>> -#ifdef CONFIG_PPC_64S_HASH_MMU
>> - return slice_get_unmapped_area(addr, len, flags,
>> - mm_ctx_user_psize(&current->mm->context), 0);
>> -#else
>> - BUG();
>> -#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)
>> -{
>> - if (radix_enabled())
>> - return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
>> -
>> -#ifdef CONFIG_PPC_64S_HASH_MMU
>> - return slice_get_unmapped_area(addr0, len, flags,
>> - mm_ctx_user_psize(&current->mm->context), 1);
>> -#else
>> - BUG();
>> -#endif
>> -}
>> -#endif /* HAVE_ARCH_UNMAPPED_AREA */
>> -
>> /*
>> * This function, called very early during the creation of a new
>> * process VM image, sets up which VM layout function to use: