On 6/4/2018 5:43 PM, Will Deacon wrote:

On Fri, Jun 01, 2018 at 06:09:16PM +0530, Chintan Pandya wrote:

quoted

Add helper macros to give virtual references to page
tables. These will be used while freeing dangling
page tables.

Signed-off-by: Chintan Pandya <redacted>
---
  arch/arm64/include/asm/pgtable.h | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7c4c8f3..ef4047f 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -580,6 +580,9 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
  
  #endif  /* CONFIG_PGTABLE_LEVELS > 3 */
  
+#define pmd_page_vaddr(pmd) __va(pmd_page_paddr(pmd))
+#define pud_page_vaddr(pud) __va(pud_page_paddr(pud))

Are these actually needed, or do pte_offset_kernel and pmd_offset do the
job already?

I introduced these macros for consistency across different arch.

Looking at pte_offset_kernel, it seems to use READ_ONCE() which looks
little costly for its intended use (in next patch) where we already have
dereferenced value. Do you still suggest to remove this ?

Will

Chintan
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