arm64/mm: generalize PMD_PRESENT_INVALID for all levels

As preparation for the next patch, which frees up the PTE_PROT_NONE
present pte and swap pte bit, generalize PMD_PRESENT_INVALID to
PTE_PRESENT_INVALID. This will then be used to mark PROT_NONE ptes (and
entries at any other level) in the next patch.

While we're at it, fix up the swap pte format comment to include
PTE_PRESENT_INVALID. This is not new, it just wasn't previously
documented.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://lore.kernel.org/r/20240503144604.151095-2-ryan.roberts@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index dd9ee67d1d87c7a4638e4090e621a966c4c2a313..cdbf51eef7a6e1fe5ba14f0881d0ffd1ebbae6ad 100644 (file)
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -21,11 +21,11 @@
 #define PTE_PROT_NONE          (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
 
 /*
- * This bit indicates that the entry is present i.e. pmd_page()
- * still points to a valid huge page in memory even if the pmd
- * has been invalidated.
+ * PTE_PRESENT_INVALID=1 & PTE_VALID=0 indicates that the pte's fields should be
+ * interpreted according to the HW layout by SW but any attempted HW access to
+ * the address will result in a fault. pte_present() returns true.
  */
-#define PMD_PRESENT_INVALID    (_AT(pteval_t, 1) << 59) /* only when !PMD_SECT_VALID */
+#define PTE_PRESENT_INVALID    (_AT(pteval_t, 1) << 59) /* only when !PTE_VALID */
 
 #define _PROT_DEFAULT          (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
 #define _PROT_SECT_DEFAULT     (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 92c9aed5e7afc5368621b3e18a23c9e033700ef1..a3e417f388e9c91ce095f8f4bfee075510e77d8f 100644 (file)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -132,6 +132,8 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
 #define pte_dirty(pte)         (pte_sw_dirty(pte) || pte_hw_dirty(pte))
 
 #define pte_valid(pte)         (!!(pte_val(pte) & PTE_VALID))
+#define pte_present_invalid(pte) \
+       ((pte_val(pte) & (PTE_VALID | PTE_PRESENT_INVALID)) == PTE_PRESENT_INVALID)
 /*
  * Execute-only user mappings do not have the PTE_USER bit set. All valid
  * kernel mappings have the PTE_UXN bit set.
@@ -261,6 +263,13 @@ static inline pte_t pte_mkpresent(pte_t pte)
        return set_pte_bit(pte, __pgprot(PTE_VALID));
 }
 
+static inline pte_t pte_mkinvalid(pte_t pte)
+{
+       pte = set_pte_bit(pte, __pgprot(PTE_PRESENT_INVALID));
+       pte = clear_pte_bit(pte, __pgprot(PTE_VALID));
+       return pte;
+}
+
 static inline pmd_t pmd_mkcont(pmd_t pmd)
 {
        return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
@@ -483,7 +492,7 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif
 
-#define pmd_present_invalid(pmd)     (!!(pmd_val(pmd) & PMD_PRESENT_INVALID))
+#define pmd_present_invalid(pmd)       pte_present_invalid(pmd_pte(pmd))
 
 static inline int pmd_present(pmd_t pmd)
 {
@@ -513,14 +522,7 @@ static inline int pmd_trans_huge(pmd_t pmd)
 #define pmd_mkclean(pmd)       pte_pmd(pte_mkclean(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)))
-
-static inline pmd_t pmd_mkinvalid(pmd_t pmd)
-{
-       pmd = set_pmd_bit(pmd, __pgprot(PMD_PRESENT_INVALID));
-       pmd = clear_pmd_bit(pmd, __pgprot(PMD_SECT_VALID));
-
-       return pmd;
-}
+#define pmd_mkinvalid(pmd)     pte_pmd(pte_mkinvalid(pmd_pte(pmd)))
 
 #define pmd_thp_or_huge(pmd)   (pmd_huge(pmd) || pmd_trans_huge(pmd))
 
@@ -1258,6 +1260,7 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
  *     bits 3-7:       swap type
  *     bits 8-57:      swap offset
  *     bit  58:        PTE_PROT_NONE (must be zero)
+ *     bit  59:        PTE_PRESENT_INVALID (must be zero)
  */
 #define __SWP_TYPE_SHIFT       3
 #define __SWP_TYPE_BITS                5