[PATCH 6.6 199/269] riscv: Use accessors to page table entries instead of direct dereference

10 Sep 2024

6.6-stable review patch.  If anyone has any objections, please let me know.
------------------
From: Alexandre Ghiti alexghiti@rivosinc.com
commit edf955647269422e387732870d04fc15933a25ea upstream.
As very well explained in commit 20a004e7b017 ("arm64: mm: Use
READ_ONCE/WRITE_ONCE when accessing page tables"), an architecture whose
page table walker can modify the PTE in parallel must use
READ_ONCE()/WRITE_ONCE() macro to avoid any compiler transformation.
So apply that to riscv which is such architecture.
Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com
Acked-by: Anup Patel anup@brainfault.org
Link: https://lore.kernel.org/r/20231213203001.179237-5-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt palmer@rivosinc.com
Signed-off-by: WangYuli wangyuli@uniontech.com
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
---
 arch/riscv/include/asm/kfence.h     |    4 +-
 arch/riscv/include/asm/pgtable-64.h |   16 +----------
 arch/riscv/include/asm/pgtable.h    |   29 ++++----------------
 arch/riscv/kernel/efi.c             |    2 -
 arch/riscv/kvm/mmu.c                |   22 +++++++--------
 arch/riscv/mm/fault.c               |   16 +++++------
 arch/riscv/mm/hugetlbpage.c         |   12 ++++----
 arch/riscv/mm/kasan_init.c          |   45 ++++++++++++++++---------------
 arch/riscv/mm/pageattr.c            |   44 +++++++++++++++----------------
 arch/riscv/mm/pgtable.c             |   51 ++++++++++++++++++++++++++++++++----
 10 files changed, 128 insertions(+), 113 deletions(-)

--- a/arch/riscv/include/asm/kfence.h
+++ b/arch/riscv/include/asm/kfence.h
@@ -18,9 +18,9 @@ static inline bool kfence_protect_page(u
    pte_t *pte = virt_to_kpte(addr);
if (protect)
-		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
+		set_pte(pte, __pte(pte_val(ptep_get(pte)) & ~_PAGE_PRESENT));
    else
-		set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
+		set_pte(pte, __pte(pte_val(ptep_get(pte)) | _PAGE_PRESENT));
flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -336,13 +336,7 @@ static inline struct page *p4d_page(p4d_
 #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
#define pud_offset pud_offset
-static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
-{
-	if (pgtable_l4_enabled)
-		return p4d_pgtable(*p4d) + pud_index(address);
-
-	return (pud_t *)p4d;
-}
+pud_t *pud_offset(p4d_t *p4d, unsigned long address);
static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
 {
@@ -400,12 +394,6 @@ static inline struct page *pgd_page(pgd_
 #define p4d_index(addr) (((addr) >> P4D_SHIFT) & (PTRS_PER_P4D - 1))
#define p4d_offset p4d_offset
-static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
-{
-	if (pgtable_l5_enabled)
-		return pgd_pgtable(*pgd) + p4d_index(address);
-
-	return (p4d_t *)pgd;
-}
+p4d_t *p4d_offset(pgd_t *pgd, unsigned long address);
#endif /* _ASM_RISCV_PGTABLE_64_H */
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -549,19 +549,12 @@ static inline void pte_clear(struct mm_s
    __set_pte_at(ptep, __pte(0));
 }
-#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
-static inline int ptep_set_access_flags(struct vm_area_struct *vma,
-					unsigned long address, pte_t *ptep,
-					pte_t entry, int dirty)
-{
-	if (!pte_same(*ptep, entry))
-		__set_pte_at(ptep, entry);
-	/*
-	 * update_mmu_cache will unconditionally execute, handling both
-	 * the case that the PTE changed and the spurious fault case.
-	 */
-	return true;
-}
+#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS	/* defined in mm/pgtable.c */
+extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
+				 pte_t *ptep, pte_t entry, int dirty);
+#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG	/* defined in mm/pgtable.c */
+extern int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long address,
+				     pte_t *ptep);
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
@@ -574,16 +567,6 @@ static inline pte_t ptep_get_and_clear(s
    return pte;
 }
-#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
-static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
-					    unsigned long address,
-					    pte_t *ptep)
-{
-	if (!pte_young(*ptep))
-		return 0;
-	return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
-}
-
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 static inline void ptep_set_wrprotect(struct mm_struct *mm,
    			      unsigned long address, pte_t *ptep)
--- a/arch/riscv/kernel/efi.c
+++ b/arch/riscv/kernel/efi.c
@@ -60,7 +60,7 @@ int __init efi_create_mapping(struct mm_
 static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
 {
    efi_memory_desc_t *md = data;
-	pte_t pte = READ_ONCE(*ptep);
+	pte_t pte = ptep_get(ptep);
    unsigned long val;
if (md->attribute & EFI_MEMORY_RO) {
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -103,7 +103,7 @@ static bool gstage_get_leaf_entry(struct
    *ptep_level = current_level;
    ptep = (pte_t *)kvm->arch.pgd;
    ptep = &ptep[gstage_pte_index(addr, current_level)];
-	while (ptep && pte_val(*ptep)) {
+	while (ptep && pte_val(ptep_get(ptep))) {
    	if (gstage_pte_leaf(ptep)) {
    		*ptep_level = current_level;
    		*ptepp = ptep;
@@ -113,7 +113,7 @@ static bool gstage_get_leaf_entry(struct
    	if (current_level) {
    		current_level--;
    		*ptep_level = current_level;
-			ptep = (pte_t *)gstage_pte_page_vaddr(*ptep);
+			ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
    		ptep = &ptep[gstage_pte_index(addr, current_level)];
    	} else {
    		ptep = NULL;
@@ -149,25 +149,25 @@ static int gstage_set_pte(struct kvm *kv
    	if (gstage_pte_leaf(ptep))
    		return -EEXIST;
-		if (!pte_val(*ptep)) {
+		if (!pte_val(ptep_get(ptep))) {
    		if (!pcache)
    			return -ENOMEM;
    		next_ptep = kvm_mmu_memory_cache_alloc(pcache);
    		if (!next_ptep)
    			return -ENOMEM;
-			*ptep = pfn_pte(PFN_DOWN(__pa(next_ptep)),
-					__pgprot(_PAGE_TABLE));
+			set_pte(ptep, pfn_pte(PFN_DOWN(__pa(next_ptep)),
+					      __pgprot(_PAGE_TABLE)));
    	} else {
    		if (gstage_pte_leaf(ptep))
    			return -EEXIST;
-			next_ptep = (pte_t *)gstage_pte_page_vaddr(*ptep);
+			next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
    	}
current_level--;
    	ptep = &next_ptep[gstage_pte_index(addr, current_level)];
    }
-	*ptep = *new_pte;
+	set_pte(ptep, *new_pte);
    if (gstage_pte_leaf(ptep))
    	gstage_remote_tlb_flush(kvm, current_level, addr);
@@ -239,11 +239,11 @@ static void gstage_op_pte(struct kvm *kv
BUG_ON(addr & (page_size - 1));
-	if (!pte_val(*ptep))
+	if (!pte_val(ptep_get(ptep)))
    	return;
if (ptep_level && !gstage_pte_leaf(ptep)) {
-		next_ptep = (pte_t *)gstage_pte_page_vaddr(*ptep);
+		next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
    	next_ptep_level = ptep_level - 1;
    	ret = gstage_level_to_page_size(next_ptep_level,
    					&next_page_size);
@@ -261,7 +261,7 @@ static void gstage_op_pte(struct kvm *kv
    	if (op == GSTAGE_OP_CLEAR)
    		set_pte(ptep, __pte(0));
    	else if (op == GSTAGE_OP_WP)
-			set_pte(ptep, __pte(pte_val(*ptep) & ~_PAGE_WRITE));
+			set_pte(ptep, __pte(pte_val(ptep_get(ptep)) & ~_PAGE_WRITE));
    	gstage_remote_tlb_flush(kvm, ptep_level, addr);
    }
 }
@@ -603,7 +603,7 @@ bool kvm_test_age_gfn(struct kvm *kvm, s
    			   &ptep, &ptep_level))
    	return false;
-	return pte_young(*ptep);
+	return pte_young(ptep_get(ptep));
 }
int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -137,24 +137,24 @@ static inline void vmalloc_fault(struct
    pgd = (pgd_t *)pfn_to_virt(pfn) + index;
    pgd_k = init_mm.pgd + index;
-	if (!pgd_present(*pgd_k)) {
+	if (!pgd_present(pgdp_get(pgd_k))) {
    	no_context(regs, addr);
    	return;
    }
-	set_pgd(pgd, *pgd_k);
+	set_pgd(pgd, pgdp_get(pgd_k));
p4d_k = p4d_offset(pgd_k, addr);
-	if (!p4d_present(*p4d_k)) {
+	if (!p4d_present(p4dp_get(p4d_k))) {
    	no_context(regs, addr);
    	return;
    }
pud_k = pud_offset(p4d_k, addr);
-	if (!pud_present(*pud_k)) {
+	if (!pud_present(pudp_get(pud_k))) {
    	no_context(regs, addr);
    	return;
    }
-	if (pud_leaf(*pud_k))
+	if (pud_leaf(pudp_get(pud_k)))
    	goto flush_tlb;
/*
@@ -162,11 +162,11 @@ static inline void vmalloc_fault(struct
     * to copy individual PTEs
     */
    pmd_k = pmd_offset(pud_k, addr);
-	if (!pmd_present(*pmd_k)) {
+	if (!pmd_present(pmdp_get(pmd_k))) {
    	no_context(regs, addr);
    	return;
    }
-	if (pmd_leaf(*pmd_k))
+	if (pmd_leaf(pmdp_get(pmd_k)))
    	goto flush_tlb;
/*
@@ -176,7 +176,7 @@ static inline void vmalloc_fault(struct
     * silently loop forever.
     */
    pte_k = pte_offset_kernel(pmd_k, addr);
-	if (!pte_present(*pte_k)) {
+	if (!pte_present(ptep_get(pte_k))) {
    	no_context(regs, addr);
    	return;
    }
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -54,7 +54,7 @@ pte_t *huge_pte_alloc(struct mm_struct *
    }
if (sz == PMD_SIZE) {
-		if (want_pmd_share(vma, addr) && pud_none(*pud))
+		if (want_pmd_share(vma, addr) && pud_none(pudp_get(pud)))
    		pte = huge_pmd_share(mm, vma, addr, pud);
    	else
    		pte = (pte_t *)pmd_alloc(mm, pud, addr);
@@ -93,11 +93,11 @@ pte_t *huge_pte_offset(struct mm_struct
    pmd_t *pmd;
pgd = pgd_offset(mm, addr);
-	if (!pgd_present(*pgd))
+	if (!pgd_present(pgdp_get(pgd)))
    	return NULL;
p4d = p4d_offset(pgd, addr);
-	if (!p4d_present(*p4d))
+	if (!p4d_present(p4dp_get(p4d)))
    	return NULL;
pud = pud_offset(p4d, addr);
@@ -105,7 +105,7 @@ pte_t *huge_pte_offset(struct mm_struct
    	/* must be pud huge, non-present or none */
    	return (pte_t *)pud;
-	if (!pud_present(*pud))
+	if (!pud_present(pudp_get(pud)))
    	return NULL;
pmd = pmd_offset(pud, addr);
@@ -113,7 +113,7 @@ pte_t *huge_pte_offset(struct mm_struct
    	/* must be pmd huge, non-present or none */
    	return (pte_t *)pmd;
-	if (!pmd_present(*pmd))
+	if (!pmd_present(pmdp_get(pmd)))
    	return NULL;
for_each_napot_order(order) {
@@ -351,7 +351,7 @@ void huge_pte_clear(struct mm_struct *mm
    	    pte_t *ptep,
    	    unsigned long sz)
 {
-	pte_t pte = READ_ONCE(*ptep);
+	pte_t pte = ptep_get(ptep);
    int i, pte_num;
if (!pte_napot(pte)) {
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -31,7 +31,7 @@ static void __init kasan_populate_pte(pm
    phys_addr_t phys_addr;
    pte_t *ptep, *p;
-	if (pmd_none(*pmd)) {
+	if (pmd_none(pmdp_get(pmd))) {
    	p = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
    	set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(p)), PAGE_TABLE));
    }
@@ -39,7 +39,7 @@ static void __init kasan_populate_pte(pm
    ptep = pte_offset_kernel(pmd, vaddr);
do {
-		if (pte_none(*ptep)) {
+		if (pte_none(ptep_get(ptep))) {
    		phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
    		set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
    		memset(__va(phys_addr), KASAN_SHADOW_INIT, PAGE_SIZE);
@@ -53,7 +53,7 @@ static void __init kasan_populate_pmd(pu
    pmd_t *pmdp, *p;
    unsigned long next;
-	if (pud_none(*pud)) {
+	if (pud_none(pudp_get(pud))) {
    	p = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
    	set_pud(pud, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
    }
@@ -63,7 +63,8 @@ static void __init kasan_populate_pmd(pu
    do {
    	next = pmd_addr_end(vaddr, end);
-		if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) {
+		if (pmd_none(pmdp_get(pmdp)) && IS_ALIGNED(vaddr, PMD_SIZE) &&
+		    (next - vaddr) >= PMD_SIZE) {
    		phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
    		if (phys_addr) {
    			set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
@@ -83,7 +84,7 @@ static void __init kasan_populate_pud(p4
    pud_t *pudp, *p;
    unsigned long next;
-	if (p4d_none(*p4d)) {
+	if (p4d_none(p4dp_get(p4d))) {
    	p = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
    	set_p4d(p4d, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
    }
@@ -93,7 +94,8 @@ static void __init kasan_populate_pud(p4
    do {
    	next = pud_addr_end(vaddr, end);
-		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
+		if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
+		    (next - vaddr) >= PUD_SIZE) {
    		phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
    		if (phys_addr) {
    			set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
@@ -113,7 +115,7 @@ static void __init kasan_populate_p4d(pg
    p4d_t *p4dp, *p;
    unsigned long next;
-	if (pgd_none(*pgd)) {
+	if (pgd_none(pgdp_get(pgd))) {
    	p = memblock_alloc(PTRS_PER_P4D * sizeof(p4d_t), PAGE_SIZE);
    	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
    }
@@ -123,7 +125,8 @@ static void __init kasan_populate_p4d(pg
    do {
    	next = p4d_addr_end(vaddr, end);
-		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) {
+		if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
+		    (next - vaddr) >= P4D_SIZE) {
    		phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
    		if (phys_addr) {
    			set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
@@ -145,7 +148,7 @@ static void __init kasan_populate_pgd(pg
    do {
    	next = pgd_addr_end(vaddr, end);
-		if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
+		if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
    	    (next - vaddr) >= PGDIR_SIZE) {
    		phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
    		if (phys_addr) {
@@ -168,7 +171,7 @@ static void __init kasan_early_clear_pud
    if (!pgtable_l4_enabled) {
    	pudp = (pud_t *)p4dp;
    } else {
-		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
+		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
    	pudp = base_pud + pud_index(vaddr);
    }
@@ -193,7 +196,7 @@ static void __init kasan_early_clear_p4d
    if (!pgtable_l5_enabled) {
    	p4dp = (p4d_t *)pgdp;
    } else {
-		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
+		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
    	p4dp = base_p4d + p4d_index(vaddr);
    }
@@ -239,14 +242,14 @@ static void __init kasan_early_populate_
    if (!pgtable_l4_enabled) {
    	pudp = (pud_t *)p4dp;
    } else {
-		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
+		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
    	pudp = base_pud + pud_index(vaddr);
    }
do {
    	next = pud_addr_end(vaddr, end);
-		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) &&
+		if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
    	    (next - vaddr) >= PUD_SIZE) {
    		phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);
    		set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
@@ -277,14 +280,14 @@ static void __init kasan_early_populate_
    if (!pgtable_l5_enabled) {
    	p4dp = (p4d_t *)pgdp;
    } else {
-		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
+		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
    	p4dp = base_p4d + p4d_index(vaddr);
    }
do {
    	next = p4d_addr_end(vaddr, end);
-		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) &&
+		if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
    	    (next - vaddr) >= P4D_SIZE) {
    		phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);
    		set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
@@ -305,7 +308,7 @@ static void __init kasan_early_populate_
    do {
    	next = pgd_addr_end(vaddr, end);
-		if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
+		if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
    	    (next - vaddr) >= PGDIR_SIZE) {
    		phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);
    		set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
@@ -381,7 +384,7 @@ static void __init kasan_shallow_populat
    do {
    	next = pud_addr_end(vaddr, end);
-		if (pud_none(*pud_k)) {
+		if (pud_none(pudp_get(pud_k))) {
    		p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
    		set_pud(pud_k, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
    		continue;
@@ -401,7 +404,7 @@ static void __init kasan_shallow_populat
    do {
    	next = p4d_addr_end(vaddr, end);
-		if (p4d_none(*p4d_k)) {
+		if (p4d_none(p4dp_get(p4d_k))) {
    		p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
    		set_p4d(p4d_k, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
    		continue;
@@ -420,7 +423,7 @@ static void __init kasan_shallow_populat
    do {
    	next = pgd_addr_end(vaddr, end);
-		if (pgd_none(*pgd_k)) {
+		if (pgd_none(pgdp_get(pgd_k))) {
    		p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
    		set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
    		continue;
@@ -451,7 +454,7 @@ static void __init create_tmp_mapping(vo
/* Copy the last p4d since it is shared with the kernel mapping. */
    if (pgtable_l5_enabled) {
-		ptr = (p4d_t *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
+		ptr = (p4d_t *)pgd_page_vaddr(pgdp_get(pgd_offset_k(KASAN_SHADOW_END)));
    	memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
    	set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
    		pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
@@ -462,7 +465,7 @@ static void __init create_tmp_mapping(vo
/* Copy the last pud since it is shared with the kernel mapping. */
    if (pgtable_l4_enabled) {
-		ptr = (pud_t *)p4d_page_vaddr(*(base_p4d + p4d_index(KASAN_SHADOW_END)));
+		ptr = (pud_t *)p4d_page_vaddr(p4dp_get(base_p4d + p4d_index(KASAN_SHADOW_END)));
    	memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
    	set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
    		pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -29,7 +29,7 @@ static unsigned long set_pageattr_masks(
 static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
    		      unsigned long next, struct mm_walk *walk)
 {
-	p4d_t val = READ_ONCE(*p4d);
+	p4d_t val = p4dp_get(p4d);
if (p4d_leaf(val)) {
    	val = __p4d(set_pageattr_masks(p4d_val(val), walk));
@@ -42,7 +42,7 @@ static int pageattr_p4d_entry(p4d_t *p4d
 static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
    		      unsigned long next, struct mm_walk *walk)
 {
-	pud_t val = READ_ONCE(*pud);
+	pud_t val = pudp_get(pud);
if (pud_leaf(val)) {
    	val = __pud(set_pageattr_masks(pud_val(val), walk));
@@ -55,7 +55,7 @@ static int pageattr_pud_entry(pud_t *pud
 static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
    		      unsigned long next, struct mm_walk *walk)
 {
-	pmd_t val = READ_ONCE(*pmd);
+	pmd_t val = pmdp_get(pmd);
if (pmd_leaf(val)) {
    	val = __pmd(set_pageattr_masks(pmd_val(val), walk));
@@ -68,7 +68,7 @@ static int pageattr_pmd_entry(pmd_t *pmd
 static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
    		      unsigned long next, struct mm_walk *walk)
 {
-	pte_t val = READ_ONCE(*pte);
+	pte_t val = ptep_get(pte);
val = __pte(set_pageattr_masks(pte_val(val), walk));
    set_pte(pte, val);
@@ -108,10 +108,10 @@ static int __split_linear_mapping_pmd(pu
    	    vaddr <= (vaddr & PMD_MASK) && end >= next)
    		continue;
-		if (pmd_leaf(*pmdp)) {
+		if (pmd_leaf(pmdp_get(pmdp))) {
    		struct page *pte_page;
-			unsigned long pfn = _pmd_pfn(*pmdp);
-			pgprot_t prot = __pgprot(pmd_val(*pmdp) & ~_PAGE_PFN_MASK);
+			unsigned long pfn = _pmd_pfn(pmdp_get(pmdp));
+			pgprot_t prot = __pgprot(pmd_val(pmdp_get(pmdp)) & ~_PAGE_PFN_MASK);
    		pte_t *ptep_new;
    		int i;
@@ -148,10 +148,10 @@ static int __split_linear_mapping_pud(p4
    	    vaddr <= (vaddr & PUD_MASK) && end >= next)
    		continue;
-		if (pud_leaf(*pudp)) {
+		if (pud_leaf(pudp_get(pudp))) {
    		struct page *pmd_page;
-			unsigned long pfn = _pud_pfn(*pudp);
-			pgprot_t prot = __pgprot(pud_val(*pudp) & ~_PAGE_PFN_MASK);
+			unsigned long pfn = _pud_pfn(pudp_get(pudp));
+			pgprot_t prot = __pgprot(pud_val(pudp_get(pudp)) & ~_PAGE_PFN_MASK);
    		pmd_t *pmdp_new;
    		int i;
@@ -197,10 +197,10 @@ static int __split_linear_mapping_p4d(pg
    	    vaddr <= (vaddr & P4D_MASK) && end >= next)
    		continue;
-		if (p4d_leaf(*p4dp)) {
+		if (p4d_leaf(p4dp_get(p4dp))) {
    		struct page *pud_page;
-			unsigned long pfn = _p4d_pfn(*p4dp);
-			pgprot_t prot = __pgprot(p4d_val(*p4dp) & ~_PAGE_PFN_MASK);
+			unsigned long pfn = _p4d_pfn(p4dp_get(p4dp));
+			pgprot_t prot = __pgprot(p4d_val(p4dp_get(p4dp)) & ~_PAGE_PFN_MASK);
    		pud_t *pudp_new;
    		int i;
@@ -427,29 +427,29 @@ bool kernel_page_present(struct page *pa
    pte_t *pte;
pgd = pgd_offset_k(addr);
-	if (!pgd_present(*pgd))
+	if (!pgd_present(pgdp_get(pgd)))
    	return false;
-	if (pgd_leaf(*pgd))
+	if (pgd_leaf(pgdp_get(pgd)))
    	return true;
p4d = p4d_offset(pgd, addr);
-	if (!p4d_present(*p4d))
+	if (!p4d_present(p4dp_get(p4d)))
    	return false;
-	if (p4d_leaf(*p4d))
+	if (p4d_leaf(p4dp_get(p4d)))
    	return true;
pud = pud_offset(p4d, addr);
-	if (!pud_present(*pud))
+	if (!pud_present(pudp_get(pud)))
    	return false;
-	if (pud_leaf(*pud))
+	if (pud_leaf(pudp_get(pud)))
    	return true;
pmd = pmd_offset(pud, addr);
-	if (!pmd_present(*pmd))
+	if (!pmd_present(pmdp_get(pmd)))
    	return false;
-	if (pmd_leaf(*pmd))
+	if (pmd_leaf(pmdp_get(pmd)))
    	return true;
pte = pte_offset_kernel(pmd, addr);
-	return pte_present(*pte);
+	return pte_present(ptep_get(pte));
 }
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c
@@ -5,6 +5,47 @@
 #include <linux/kernel.h>
 #include <linux/pgtable.h>
+int ptep_set_access_flags(struct vm_area_struct *vma,
+			  unsigned long address, pte_t *ptep,
+			  pte_t entry, int dirty)
+{
+	if (!pte_same(ptep_get(ptep), entry))
+		__set_pte_at(ptep, entry);
+	/*
+	 * update_mmu_cache will unconditionally execute, handling both
+	 * the case that the PTE changed and the spurious fault case.
+	 */
+	return true;
+}
+
+int ptep_test_and_clear_young(struct vm_area_struct *vma,
+			      unsigned long address,
+			      pte_t *ptep)
+{
+	if (!pte_young(ptep_get(ptep)))
+		return 0;
+	return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
+}
+EXPORT_SYMBOL_GPL(ptep_test_and_clear_young);
+
+#ifdef CONFIG_64BIT
+pud_t *pud_offset(p4d_t *p4d, unsigned long address)
+{
+	if (pgtable_l4_enabled)
+		return p4d_pgtable(p4dp_get(p4d)) + pud_index(address);
+
+	return (pud_t *)p4d;
+}
+
+p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
+{
+	if (pgtable_l5_enabled)
+		return pgd_pgtable(pgdp_get(pgd)) + p4d_index(address);
+
+	return (p4d_t *)pgd;
+}
+#endif
+
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
 {
@@ -25,7 +66,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t
int pud_clear_huge(pud_t *pud)
 {
-	if (!pud_leaf(READ_ONCE(*pud)))
+	if (!pud_leaf(pudp_get(pud)))
    	return 0;
    pud_clear(pud);
    return 1;
@@ -33,7 +74,7 @@ int pud_clear_huge(pud_t *pud)
int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
-	pmd_t *pmd = pud_pgtable(*pud);
+	pmd_t *pmd = pud_pgtable(pudp_get(pud));
    int i;
pud_clear(pud);
@@ -63,7 +104,7 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t
int pmd_clear_huge(pmd_t *pmd)
 {
-	if (!pmd_leaf(READ_ONCE(*pmd)))
+	if (!pmd_leaf(pmdp_get(pmd)))
    	return 0;
    pmd_clear(pmd);
    return 1;
@@ -71,7 +112,7 @@ int pmd_clear_huge(pmd_t *pmd)
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
-	pte_t *pte = (pte_t *)pmd_page_vaddr(*pmd);
+	pte_t *pte = (pte_t *)pmd_page_vaddr(pmdp_get(pmd));
pmd_clear(pmd);
@@ -88,7 +129,7 @@ pmd_t pmdp_collapse_flush(struct vm_area
    pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-	VM_BUG_ON(pmd_trans_huge(*pmdp));
+	VM_BUG_ON(pmd_trans_huge(pmdp_get(pmdp)));
    /*
     * When leaf PTE entries (regular pages) are collapsed into a leaf
     * PMD entry (huge page), a valid non-leaf PTE is converted into a

    

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[PATCH 6.6 199/269] riscv: Use accessors to page table entries instead of direct dereference