[PATCH v2 04/14] arm64/mm: pte_clear(): New layer to manage contig bit

Ryan Roberts
2023-11-15T16:30:50Z

Create a new layer for the in-table PTE manipulation APIs. For now, The
existing API is prefixed with double underscore to become the
arch-private API and the public API is just a simple wrapper that calls
the private API.

The public API implementation will subsequently be used to transparently
manipulate the contiguous bit where appropriate. But since there are
already some contig-aware users (e.g. hugetlb, kernel mapper), we must
first ensure those users use the private API directly so that the future
contig-bit manipulations in the public API do not interfere with those
existing uses.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
arch/arm64/include/asm/pgtable.h | 3 ++-
arch/arm64/mm/fixmap.c | 2 +-
arch/arm64/mm/hugetlbpage.c | 2 +-
arch/arm64/mm/mmu.c | 2 +-
4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 323ec91add60..1464e990580a 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -93,7 +93,7 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
__pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))

#define pte_none(pte) (!pte_val(pte))
-#define pte_clear(mm, addr, ptep) \
+#define __pte_clear(mm, addr, ptep) \
__set_pte(ptep, __pte(0))
#define pte_page(pte) (pfn_to_page(pte_pfn(pte)))

@@ -1121,6 +1121,7 @@ extern void ptep_modify_prot_commit(struct vm_area_struct *vma,

#define set_pte __set_pte
#define set_ptes __set_ptes
+#define pte_clear __pte_clear

#endif /* !__ASSEMBLY__ */

diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index 51cd4501816d..bfc02568805a 100644
--- a/arch/arm64/mm/fixmap.c
+++ b/arch/arm64/mm/fixmap.c
@@ -123,7 +123,7 @@ void __set_fixmap(enum fixed_addresses idx,
if (pgprot_val(flags)) {
__set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
} else {
- pte_clear(&init_mm, addr, ptep);
+ __pte_clear(&init_mm, addr, ptep);
flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
}
}
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 741cb53672fd..510b2d4b89a9 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -400,7 +400,7 @@ void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
ncontig = num_contig_ptes(sz, &pgsize);

for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
- pte_clear(mm, addr, ptep);
+ __pte_clear(mm, addr, ptep);
}

pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index e884279b268e..080e9b50f595 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -859,7 +859,7 @@ static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
continue;

WARN_ON(!pte_present(pte));
- pte_clear(&init_mm, addr, ptep);
+ __pte_clear(&init_mm, addr, ptep);
flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
if (free_mapped)
free_hotplug_page_range(pte_page(pte),
--
2.25.1