On 30/04/2024 12:37, David Hildenbrand wrote:
On 30.04.24 13:11, Catalin Marinas wrote:
On Mon, Apr 29, 2024 at 06:15:45PM +0100, Ryan Roberts wrote:
On 29/04/2024 17:20, Catalin Marinas wrote:
On Mon, Apr 29, 2024 at 03:02:05PM +0100, Ryan Roberts wrote:
diff --git a/arch/arm64/include/asm/pgtable-prot.h
b/arch/arm64/include/asm/pgtable-prot.h
index dd9ee67d1d87..de62e6881154 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -18,14 +18,7 @@
#define PTE_DIRTY (_AT(pteval_t, 1) << 55)
#define PTE_SPECIAL (_AT(pteval_t, 1) << 56)
#define PTE_DEVMAP (_AT(pteval_t, 1) << 57)
-#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.
- */
-#define PMD_PRESENT_INVALID (_AT(pteval_t, 1) << 59) /* only when
!PMD_SECT_VALID */
+#define PTE_INVALID (_AT(pteval_t, 1) << 59) /* only when
!PTE_VALID */
Nitpick - I prefer the PTE_PRESENT_INVALID name as it makes it clearer
it's a present pte. We already have PTE_VALID, calling it PTE_INVALID
looks like a negation only.
Meh, for me the pte can only be valid or invalid if it is present. So it's
implicit. And if you have PTE_PRESENT_INVALID you should also have
PTE_PRESENT_VALID.
We also have pte_mkinvalid(), which is core-mm-defined. In your scheme, surely
it should be pte_mkpresent_invalid()?
But you're the boss, I'll change this to PTE_PRESENT_INVALID. :-(
TBH, I don't have a strong opinion but best to avoid the bikeshedding.
I'll leave the decision to you ;). It would match the pmd_mkinvalid()
core code. But if you drop 'present' make sure you add a comment above
that it's meant for present ptes.
FWIW, I was confused by
present = valid | invalid
OK fair enough.
Something like
present = present_valid | present_invalid
I don't want to change pte_valid() to pte_present_valid(); that would also be a
fair bit of churn.
I'll take Catalin's suggestion and make this PTE_PRESENT_INVALID and
pte_present_invalid(). And obviously leave pmd_mkinvalid() as it is.
(Conversation in the other thread has concluded that it's ok to invalidate a
non-present pmd afterall).