arm64/mm: convert READ_ONCE(*ptep) to ptep_get(ptep)

There are a number of places in the arch code that read a pte by using the
READ_ONCE() macro.  Refactor these call sites to instead use the
ptep_get() helper, which itself is a READ_ONCE().  Generated code should
be the same.

This will benefit us when we shortly introduce the transparent contpte
support.  In this case, ptep_get() will become more complex so we now have
all the code abstracted through it.

Link: https://lkml.kernel.org/r/20240215103205.2607016-8-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 9 insertions, 3 deletions

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index b6d3e9e0a946..de034ca40bad 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -275,6 +275,12 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 	}
 }
 
+#define ptep_get ptep_get
+static inline pte_t ptep_get(pte_t *ptep)
+{
+	return READ_ONCE(*ptep);
+}
+
 extern void __sync_icache_dcache(pte_t pteval);
 bool pgattr_change_is_safe(u64 old, u64 new);
 
@@ -302,7 +308,7 @@ static inline void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep,
 	if (!IS_ENABLED(CONFIG_DEBUG_VM))
 		return;
 
-	old_pte = READ_ONCE(*ptep);
+	old_pte = ptep_get(ptep);
 
 	if (!pte_valid(old_pte) || !pte_valid(pte))
 		return;
@@ -904,7 +910,7 @@ static inline int __ptep_test_and_clear_young(pte_t *ptep)
 {
 	pte_t old_pte, pte;
 
-	pte = READ_ONCE(*ptep);
+	pte = ptep_get(ptep);
 	do {
 		old_pte = pte;
 		pte = pte_mkold(pte);
@@ -986,7 +992,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
 {
 	pte_t old_pte, pte;
 
-	pte = READ_ONCE(*ptep);
+	pte = ptep_get(ptep);
 	do {
 		old_pte = pte;
 		pte = pte_wrprotect(pte);