[PATCH v3 03/15] arm64/mm: set_pte(): New layer to manage contig bit

Ryan Roberts
2023-12-04T10:55:10Z

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