Le 15/06/2020 à 11:22, Mike Rapoport a écrit :
From: Mike Rapoport <r...@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 <r...@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.le...@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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