The patch titled
Subject: arm64/mm: convert READ_ONCE(*ptep) to ptep_get(ptep)
has been added to the -mm mm-unstable branch. Its filename is
arm64-mm-convert-read_onceptep-to-ptep_getptep.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm64-mm-convert-read_onceptep-to-ptep_getptep.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryan Roberts <ryan.roberts@xxxxxxx>
Subject: arm64/mm: convert READ_ONCE(*ptep) to ptep_get(ptep)
Date: Thu, 15 Feb 2024 10:31:54 +0000
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@xxxxxxx
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Tested-by: John Hubbard <jhubbard@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Barry Song <21cnbao@xxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/pgtable.h | 12 +++++++++---
arch/arm64/kernel/efi.c | 2 +-
arch/arm64/mm/fault.c | 4 ++--
arch/arm64/mm/hugetlbpage.c | 6 +++---
arch/arm64/mm/kasan_init.c | 2 +-
arch/arm64/mm/mmu.c | 12 ++++++------
arch/arm64/mm/pageattr.c | 4 ++--
arch/arm64/mm/trans_pgd.c | 2 +-
8 files changed, 25 insertions(+), 19 deletions(-)
--- a/arch/arm64/include/asm/pgtable.h~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/include/asm/pgtable.h
@@ -275,6 +275,12 @@ static inline void set_pte(pte_t *ptep,
}
}
+#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_upda
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_
{
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(st
{
pte_t old_pte, pte;
- pte = READ_ONCE(*ptep);
+ pte = ptep_get(ptep);
do {
old_pte = pte;
pte = pte_wrprotect(pte);
--- a/arch/arm64/kernel/efi.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/kernel/efi.c
@@ -103,7 +103,7 @@ static int __init set_permissions(pte_t
{
struct set_perm_data *spd = data;
const efi_memory_desc_t *md = spd->md;
- pte_t pte = READ_ONCE(*ptep);
+ pte_t pte = ptep_get(ptep);
if (md->attribute & EFI_MEMORY_RO)
pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
--- a/arch/arm64/mm/fault.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/fault.c
@@ -191,7 +191,7 @@ static void show_pte(unsigned long addr)
if (!ptep)
break;
- pte = READ_ONCE(*ptep);
+ pte = ptep_get(ptep);
pr_cont(", pte=%016llx", pte_val(pte));
pte_unmap(ptep);
} while(0);
@@ -214,7 +214,7 @@ int ptep_set_access_flags(struct vm_area
pte_t entry, int dirty)
{
pteval_t old_pteval, pteval;
- pte_t pte = READ_ONCE(*ptep);
+ pte_t pte = ptep_get(ptep);
if (pte_same(pte, entry))
return 0;
--- a/arch/arm64/mm/hugetlbpage.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/hugetlbpage.c
@@ -485,7 +485,7 @@ void huge_ptep_set_wrprotect(struct mm_s
size_t pgsize;
pte_t pte;
- if (!pte_cont(READ_ONCE(*ptep))) {
+ if (!pte_cont(ptep_get(ptep))) {
ptep_set_wrprotect(mm, addr, ptep);
return;
}
@@ -510,7 +510,7 @@ pte_t huge_ptep_clear_flush(struct vm_ar
size_t pgsize;
int ncontig;
- if (!pte_cont(READ_ONCE(*ptep)))
+ if (!pte_cont(ptep_get(ptep)))
return ptep_clear_flush(vma, addr, ptep);
ncontig = find_num_contig(mm, addr, ptep, &pgsize);
@@ -543,7 +543,7 @@ pte_t huge_ptep_modify_prot_start(struct
* 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 huge_ptep_clear_flush(vma, addr, ptep);
}
return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep);
--- a/arch/arm64/mm/kasan_init.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/kasan_init.c
@@ -113,7 +113,7 @@ static void __init kasan_pte_populate(pm
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));
- } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
+ } while (ptep++, addr = next, addr != end && pte_none(ptep_get(ptep)));
}
static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
--- a/arch/arm64/mm/mmu.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/mmu.c
@@ -173,7 +173,7 @@ static void init_pte(pmd_t *pmdp, unsign
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, unsign
* 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_
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 *
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 *
*/
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_a
* 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);
--- a/arch/arm64/mm/pageattr.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/pageattr.c
@@ -36,7 +36,7 @@ bool can_set_direct_map(void)
static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
{
struct page_change_data *cdata = data;
- pte_t pte = READ_ONCE(*ptep);
+ pte_t pte = ptep_get(ptep);
pte = clear_pte_bit(pte, cdata->clear_mask);
pte = set_pte_bit(pte, cdata->set_mask);
@@ -245,5 +245,5 @@ bool kernel_page_present(struct page *pa
return true;
ptep = pte_offset_kernel(pmdp, addr);
- return pte_valid(READ_ONCE(*ptep));
+ return pte_valid(ptep_get(ptep));
}
--- a/arch/arm64/mm/trans_pgd.c~arm64-mm-convert-read_onceptep-to-ptep_getptep
+++ a/arch/arm64/mm/trans_pgd.c
@@ -33,7 +33,7 @@ static void *trans_alloc(struct trans_pg
static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
{
- pte_t pte = READ_ONCE(*src_ptep);
+ pte_t pte = ptep_get(src_ptep);
if (pte_valid(pte)) {
/*
_
Patches currently in -mm which might be from ryan.roberts@xxxxxxx are
tools-mm-add-thpmaps-script-to-dump-thp-usage-info.patch
arm64-mm-make-set_ptes-robust-when-oas-cross-48-bit-boundary.patch
mm-clarify-the-spec-for-set_ptes.patch
mm-thp-batch-collapse-pmd-with-set_ptes.patch
mm-introduce-pte_advance_pfn-and-use-for-pte_next_pfn.patch
arm64-mm-convert-pte_next_pfn-to-pte_advance_pfn.patch
x86-mm-convert-pte_next_pfn-to-pte_advance_pfn.patch
mm-tidy-up-pte_next_pfn-definition.patch
arm64-mm-convert-read_onceptep-to-ptep_getptep.patch
arm64-mm-convert-set_pte_at-to-set_ptes-1.patch
arm64-mm-convert-ptep_clear-to-ptep_get_and_clear.patch
arm64-mm-new-ptep-layer-to-manage-contig-bit.patch
arm64-mm-split-__flush_tlb_range-to-elide-trailing-dsb.patch
arm64-mm-wire-up-pte_cont-for-user-mappings.patch
arm64-mm-implement-new-wrprotect_ptes-batch-api.patch
arm64-mm-implement-new-clear_full_ptes-batch-apis.patch
mm-add-pte_batch_hint-to-reduce-scanning-in-folio_pte_batch.patch
arm64-mm-implement-pte_batch_hint.patch
arm64-mm-__always_inline-to-improve-fork-perf.patch
arm64-mm-automatically-fold-contpte-mappings.patch
