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powerpc/mm: Move setting PTE specific flags to pfn_pmd()

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powerpc used to set the PTE specific flags in set_pte_at(). That is
different from other architectures. To be consistent with other
architectures powerpc updated pfn_pte() to set _PAGE_PTE in commit
379c926d63 ("powerpc/mm: move setting pte specific flags to
pfn_pte")

That commit didn't do the same for pfn_pmd() because we expect
pmd_mkhuge() to do that. But as per Linus that is a bad rule:

  The rule that you must use "pmd_mkhuge()" seems _completely_ wrong.
  The only valid use to ever make a pmd out of a pfn is to make a
  huge-page.

Hence update pfn_pmd() to set _PAGE_PTE.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201022091115.39568-1-aneesh.kumar@linux.ibm.com
This commit is contained in:
Aneesh Kumar K.V 2020-10-22 14:41:15 +05:30 • committed by Michael Ellerman
parent 1891ef21d9
commit 53f45ecc9c
2 changed files with 23 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

17
arch/powerpc/include/asm/book3s/64/pgtable.h
View file

@ -1231,13 +1231,28 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
return hash__pmd_same(pmd_a, pmd_b);
}
static inline pmd_t pmd_mkhuge(pmd_t pmd)
static inline pmd_t __pmd_mkhuge(pmd_t pmd)
{
if (radix_enabled())
return radix__pmd_mkhuge(pmd);
return hash__pmd_mkhuge(pmd);
}
/*
* pfn_pmd return a pmd_t that can be used as pmd pte entry.
*/
static inline pmd_t pmd_mkhuge(pmd_t pmd)
{
#ifdef CONFIG_DEBUG_VM
if (radix_enabled())
WARN_ON((pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE)) == 0);
else
WARN_ON((pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE | H_PAGE_THP_HUGE)) !=
cpu_to_be64(_PAGE_PTE | H_PAGE_THP_HUGE));
#endif
return pmd;
}
#define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
extern int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,

8
arch/powerpc/mm/book3s64/pgtable.c
View file

@ -136,12 +136,18 @@ static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
return __pmd(pmd_val(pmd) | pgprot_val(pgprot));
}
/*
* At some point we should be able to get rid of
* pmd_mkhuge() and mk_huge_pmd() when we update all the
* other archs to mark the pmd huge in pfn_pmd()
*/
pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
{
unsigned long pmdv;
pmdv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK;
return pmd_set_protbits(__pmd(pmdv), pgprot);
return __pmd_mkhuge(pmd_set_protbits(__pmd(pmdv), pgprot));
}
pmd_t mk_pmd(struct page *page, pgprot_t pgprot)