3.16.37-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Catalin Marinas <catalin.marinas@xxxxxxx>
commit 5bb1cc0ff9a6b68871970737e6c4c16919928d8b upstream.
Currently, pmd_present() only checks for a non-zero value, returning
true even after pmd_mknotpresent() (which only clears the type bits).
This patch converts pmd_present() to using pte_present(), similar to the
other pmd_*() checks. As a side effect, it will return true for
PROT_NONE mappings, though they are not yet used by the kernel with
transparent huge pages.
For consistency, also change pmd_mknotpresent() to only clear the
PMD_SECT_VALID bit, even though the PMD_TABLE_BIT is already 0 for block
mappings (no functional change). The unused PMD_SECT_PROT_NONE
definition is removed as transparent huge pages use the pte page prot
values.
Fixes: 9c7e535fcc17 ("arm64: mm: Route pmd thp functions through pte equivalents")
Reviewed-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/pgtable-hwdef.h | 1 -
arch/arm64/include/asm/pgtable.h | 4 ++--
2 files changed, 2 insertions(+), 3 deletions(-)
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -45,7 +45,6 @@
* Section
*/
#define PMD_SECT_VALID (_AT(pmdval_t, 1) << 0)
-#define PMD_SECT_PROT_NONE (_AT(pmdval_t, 1) << 58)
#define PMD_SECT_USER (_AT(pmdval_t, 1) << 6) /* AP[1] */
#define PMD_SECT_RDONLY (_AT(pmdval_t, 1) << 7) /* AP[2] */
#define PMD_SECT_S (_AT(pmdval_t, 3) << 8)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -250,6 +250,7 @@ static inline pmd_t pte_pmd(pte_t pte)
#define pmd_trans_splitting(pmd) pte_special(pmd_pte(pmd))
#endif
+#define pmd_present(pmd) pte_present(pmd_pte(pmd))
#define pmd_young(pmd) pte_young(pmd_pte(pmd))
#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
#define pmd_mksplitting(pmd) pte_pmd(pte_mkspecial(pmd_pte(pmd)))
@@ -257,7 +258,7 @@ static inline pmd_t pte_pmd(pte_t pte)
#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
-#define pmd_mknotpresent(pmd) (__pmd(pmd_val(pmd) & ~PMD_TYPE_MASK))
+#define pmd_mknotpresent(pmd) (__pmd(pmd_val(pmd) & ~PMD_SECT_VALID))
#define __HAVE_ARCH_PMD_WRITE
#define pmd_write(pmd) pte_write(pmd_pte(pmd))
@@ -294,7 +295,6 @@ extern pgprot_t phys_mem_access_prot(str
unsigned long size, pgprot_t vma_prot);
#define pmd_none(pmd) (!pmd_val(pmd))
-#define pmd_present(pmd) (pmd_val(pmd))
#define pmd_bad(pmd) (!(pmd_val(pmd) & 2))
--
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