[PATCH v2 02/14] arm64/mm: set_pte(): New layer to manage contig bit

[Ryan Roberts <ryan.roberts@arm.com>]

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 | 12 ++++++++----
 arch/arm64/kernel/efi.c          |  2 +-
 arch/arm64/mm/fixmap.c           |  2 +-
 arch/arm64/mm/kasan_init.c       |  4 ++--
 arch/arm64/mm/mmu.c              |  2 +-
 arch/arm64/mm/pageattr.c         |  2 +-
 arch/arm64/mm/trans_pgd.c        |  4 ++--
 7 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index b19a8aee684c..650d4f4bb6dc 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -93,7 +93,8 @@ 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)	set_pte(ptep, __pte(0))
+#define pte_clear(mm, addr, ptep) \
+				__set_pte(ptep, __pte(0))
 #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
 
 /*
@@ -261,7 +262,7 @@ static inline pte_t pte_mkdevmap(pte_t pte)
 	return set_pte_bit(pte, __pgprot(PTE_DEVMAP | PTE_SPECIAL));
 }
 
-static inline void set_pte(pte_t *ptep, pte_t pte)
+static inline void __set_pte(pte_t *ptep, pte_t pte)
 {
 	WRITE_ONCE(*ptep, pte);
 
@@ -350,7 +351,7 @@ static inline void set_ptes(struct mm_struct *mm,
 
 	for (;;) {
 		__check_safe_pte_update(mm, ptep, pte);
-		set_pte(ptep, pte);
+		__set_pte(ptep, pte);
 		if (--nr == 0)
 			break;
 		ptep++;
@@ -534,7 +535,7 @@ static inline void __set_pte_at(struct mm_struct *mm,
 {
 	__sync_cache_and_tags(pte, nr);
 	__check_safe_pte_update(mm, ptep, pte);
-	set_pte(ptep, pte);
+	__set_pte(ptep, pte);
 }
 
 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
@@ -1118,6 +1119,9 @@ extern pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
 extern void ptep_modify_prot_commit(struct vm_area_struct *vma,
 				    unsigned long addr, pte_t *ptep,
 				    pte_t old_pte, pte_t new_pte);
+
+#define set_pte					__set_pte
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_PGTABLE_H */
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 0228001347be..44288a12fc6c 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -111,7 +111,7 @@ static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
 		pte = set_pte_bit(pte, __pgprot(PTE_PXN));
 	else if (system_supports_bti_kernel() && spd->has_bti)
 		pte = set_pte_bit(pte, __pgprot(PTE_GP));
-	set_pte(ptep, pte);
+	__set_pte(ptep, pte);
 	return 0;
 }
 
diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index c0a3301203bd..51cd4501816d 100644
--- a/arch/arm64/mm/fixmap.c
+++ b/arch/arm64/mm/fixmap.c
@@ -121,7 +121,7 @@ void __set_fixmap(enum fixed_addresses idx,
 	ptep = fixmap_pte(addr);
 
 	if (pgprot_val(flags)) {
-		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
+		__set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
 	} else {
 		pte_clear(&init_mm, addr, ptep);
 		flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 555285ebd5af..5eade712e9e5 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -112,7 +112,7 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
 		if (!early)
 			memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
 		next = addr + PAGE_SIZE;
-		set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
+		__set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
 	} while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
 }
 
@@ -266,7 +266,7 @@ static void __init kasan_init_shadow(void)
 	 * so we should make sure that it maps the zero page read-only.
 	 */
 	for (i = 0; i < PTRS_PER_PTE; i++)
-		set_pte(&kasan_early_shadow_pte[i],
+		__set_pte(&kasan_early_shadow_pte[i],
 			pfn_pte(sym_to_pfn(kasan_early_shadow_page),
 				PAGE_KERNEL_RO));
 
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 15f6347d23b6..e884279b268e 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -178,7 +178,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
 	do {
 		pte_t old_pte = READ_ONCE(*ptep);
 
-		set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
+		__set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
 
 		/*
 		 * After the PTE entry has been populated once, we
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 8e2017ba5f1b..057097acf9e0 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -41,7 +41,7 @@ static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
 	pte = clear_pte_bit(pte, cdata->clear_mask);
 	pte = set_pte_bit(pte, cdata->set_mask);
 
-	set_pte(ptep, pte);
+	__set_pte(ptep, pte);
 	return 0;
 }
 
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 7b14df3c6477..230b607cf881 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -41,7 +41,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
 		 * read only (code, rodata). Clear the RDONLY bit from
 		 * the temporary mappings we use during restore.
 		 */
-		set_pte(dst_ptep, pte_mkwrite_novma(pte));
+		__set_pte(dst_ptep, pte_mkwrite_novma(pte));
 	} else if ((debug_pagealloc_enabled() ||
 		   is_kfence_address((void *)addr)) && !pte_none(pte)) {
 		/*
@@ -55,7 +55,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
 		 */
 		BUG_ON(!pfn_valid(pte_pfn(pte)));
 
-		set_pte(dst_ptep, pte_mkpresent(pte_mkwrite_novma(pte)));
+		__set_pte(dst_ptep, pte_mkpresent(pte_mkwrite_novma(pte)));
 	}
 }
 
-- 
2.25.1