Messages in this thread | | | Subject | Re: [PATCH] powerpc/8xx: use pmd_off() to access a PMD entry in pte_update() | From | Christophe Leroy <> | Date | Mon, 15 Jun 2020 11:32:42 +0200 |
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Le 15/06/2020 à 11:22, Mike Rapoport a écrit : > From: Mike Rapoport <rppt@linux.ibm.com> > > The pte_update() implementation for PPC_8xx unfolds page table from the PGD > level to access a PMD entry. Since 8xx has only 2-level page table this can > be simplified with pmd_off() shortcut. > > Replace explicit unfolding with pmd_off() and drop defines of pgd_index() > and pgd_offset() that are no longer needed. > > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Nice. When I implemented this function, I was not able to use pmd_ptr() due to some circular header inclusion (See comment in commit log). Looks like since the replacement of pmd_ptr() by pmd_off(), it works.
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Christophe
> --- > > I think it's powerpc material, but I won't mind if Andrew picks it up :) > > > arch/powerpc/include/asm/nohash/32/pgtable.h | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h > index b56f14160ae5..5a590ceaec14 100644 > --- a/arch/powerpc/include/asm/nohash/32/pgtable.h > +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h > @@ -205,10 +205,6 @@ static inline void pmd_clear(pmd_t *pmdp) > *pmdp = __pmd(0); > } > > -/* to find an entry in a page-table-directory */ > -#define pgd_index(address) ((address) >> PGDIR_SHIFT) > -#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address)) > - > /* > * PTE updates. This function is called whenever an existing > * valid PTE is updated. This does -not- include set_pte_at() > @@ -230,6 +226,8 @@ static inline void pmd_clear(pmd_t *pmdp) > * For other page sizes, we have a single entry in the table. > */ > #ifdef CONFIG_PPC_8xx > +static pmd_t *pmd_off(struct mm_struct *mm, unsigned long addr); > + > static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p, > unsigned long clr, unsigned long set, int huge) > { > @@ -237,7 +235,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p > pte_basic_t old = pte_val(*p); > pte_basic_t new = (old & ~(pte_basic_t)clr) | set; > int num, i; > - pmd_t *pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr); > + pmd_t *pmd = pmd_off(mm, addr); > > if (!huge) > num = PAGE_SIZE / SZ_4K; >
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