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Subject[PATCH] riscv: Fix superpage handling in kernel_page_present()
Date
Add checks by p*d_leaf() functions.
Though we don't have to use pgd_leaf() and p4d_leaf() as
of now, I include them in this patch for the future
compatibility.

I tested this patch on HiFive Unmatched.

Signed-off-by: Naoki Hayama <naoki.hayama@lineo.co.jp>
---
arch/riscv/mm/pageattr.c | 44 +++++++++++++++++++++++++---------------
1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index 5e49e4b4a4cc..125eea4d13c7 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -208,28 +208,40 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
bool kernel_page_present(struct page *page)
{
unsigned long addr = (unsigned long)page_address(page);
- pgd_t *pgd;
- pud_t *pud;
- p4d_t *p4d;
- pmd_t *pmd;
- pte_t *pte;
-
- pgd = pgd_offset_k(addr);
- if (!pgd_present(*pgd))
+ pgd_t *pgdp, pgd;
+ p4d_t *p4dp, p4d;
+ pud_t *pudp, pud;
+ pmd_t *pmdp, pmd;
+ pte_t *ptep;
+
+ pgdp = pgd_offset_k(addr);
+ pgd = READ_ONCE(*pgdp);
+ if (!pgd_present(pgd))
return false;
+ if (pgd_leaf(pgd))
+ return true;

- p4d = p4d_offset(pgd, addr);
- if (!p4d_present(*p4d))
+ p4dp = p4d_offset(pgdp, addr);
+ p4d = READ_ONCE(*p4dp);
+ if (!p4d_present(p4d))
return false;
+ if (p4d_leaf(p4d))
+ return true;

- pud = pud_offset(p4d, addr);
- if (!pud_present(*pud))
+ pudp = pud_offset(p4dp, addr);
+ pud = READ_ONCE(*pudp);
+ if (!pud_present(pud))
return false;
+ if (pud_leaf(pud))
+ return true;

- pmd = pmd_offset(pud, addr);
- if (!pmd_present(*pmd))
+ pmdp = pmd_offset(pudp, addr);
+ pmd = READ_ONCE(*pmdp);
+ if (!pmd_present(pmd))
return false;
+ if (pmd_leaf(pmd))
+ return true;

- pte = pte_offset_kernel(pmd, addr);
- return pte_present(*pte);
+ ptep = pte_offset_kernel(pmdp, addr);
+ return pte_present(READ_ONCE(*ptep));
}
--
2.17.1
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