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, 6 insertions, 6 deletions

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 3a27d887f7dd..343629a17042 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -173,7 +173,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
 
 	ptep = pte_set_fixmap_offset(pmdp, addr);
 	do {
-		pte_t old_pte = READ_ONCE(*ptep);
+		pte_t old_pte = ptep_get(ptep);
 
 		set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
 
@@ -182,7 +182,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
 		 * only allow updates to the permission attributes.
 		 */
 		BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
-					      READ_ONCE(pte_val(*ptep))));
+					      pte_val(ptep_get(ptep))));
 
 		phys += PAGE_SIZE;
 	} while (ptep++, addr += PAGE_SIZE, addr != end);
@@ -852,7 +852,7 @@ static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
 
 	do {
 		ptep = pte_offset_kernel(pmdp, addr);
-		pte = READ_ONCE(*ptep);
+		pte = ptep_get(ptep);
 		if (pte_none(pte))
 			continue;
 
@@ -985,7 +985,7 @@ static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
 
 	do {
 		ptep = pte_offset_kernel(pmdp, addr);
-		pte = READ_ONCE(*ptep);
+		pte = ptep_get(ptep);
 
 		/*
 		 * This is just a sanity check here which verifies that
@@ -1004,7 +1004,7 @@ static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
 	 */
 	ptep = pte_offset_kernel(pmdp, 0UL);
 	for (i = 0; i < PTRS_PER_PTE; i++) {
-		if (!pte_none(READ_ONCE(ptep[i])))
+		if (!pte_none(ptep_get(&ptep[i])))
 			return;
 	}
 
@@ -1473,7 +1473,7 @@ pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte
 		 * when the permission changes from executable to non-executable
 		 * in cases where cpu is affected with errata #2645198.
 		 */
-		if (pte_user_exec(READ_ONCE(*ptep)))
+		if (pte_user_exec(ptep_get(ptep)))
 			return ptep_clear_flush(vma, addr, ptep);
 	}
 	return ptep_get_and_clear(vma->vm_mm, addr, ptep);