Re: [PATCH v2 4/4] riscv: Use accessors to page table entries instead of direct dereference
From: Anup Patel
Date: Thu Dec 14 2023 - 00:35:35 EST
On Thu, Dec 14, 2023 at 2:04 AM Alexandre Ghiti <alexghiti@xxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxx>
For KVM RISC-V:
Acked-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Thanks,
Anup
> ---
> 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(-)
>
> diff --git a/arch/riscv/include/asm/kfence.h b/arch/riscv/include/asm/kfence.h
> index 0bbffd528096..7388edd88986 100644
> --- a/arch/riscv/include/asm/kfence.h
> +++ b/arch/riscv/include/asm/kfence.h
> @@ -18,9 +18,9 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect)
> 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);
>
> diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
> index 5d8431a390dd..b42017d76924 100644
> --- a/arch/riscv/include/asm/pgtable-64.h
> +++ b/arch/riscv/include/asm/pgtable-64.h
> @@ -340,13 +340,7 @@ static inline struct page *p4d_page(p4d_t 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)
> {
> @@ -404,12 +398,6 @@ static inline struct page *pgd_page(pgd_t 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 */
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index c9f4b250b4ee..3773f454f0fa 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -544,19 +544,12 @@ static inline void pte_clear(struct mm_struct *mm,
> __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,
> @@ -569,16 +562,6 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> 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)
> diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c
> index aa6209a74c83..b64bf1624a05 100644
> --- a/arch/riscv/kernel/efi.c
> +++ b/arch/riscv/kernel/efi.c
> @@ -60,7 +60,7 @@ int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
> 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) {
> diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> index 068c74593871..a9e2fd7245e1 100644
> --- a/arch/riscv/kvm/mmu.c
> +++ b/arch/riscv/kvm/mmu.c
> @@ -103,7 +103,7 @@ static bool gstage_get_leaf_entry(struct kvm *kvm, gpa_t addr,
> *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 kvm *kvm, gpa_t addr,
> 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 *kvm, u32 level,
> 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 *kvm, gpa_t addr,
>
> 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 *kvm, gpa_t addr,
> 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, struct kvm_gfn_range *range)
> &ptep, &ptep_level))
> return false;
>
> - return pte_young(*ptep);
> + return pte_young(ptep_get(ptep));
> }
>
> int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 90d4ba36d1d0..76f1df709a21 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -136,24 +136,24 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
> 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;
>
> /*
> @@ -161,11 +161,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
> * 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;
>
> /*
> @@ -175,7 +175,7 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
> * 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;
> }
> diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
> index b52f0210481f..431596c0e20e 100644
> --- a/arch/riscv/mm/hugetlbpage.c
> +++ b/arch/riscv/mm/hugetlbpage.c
> @@ -54,7 +54,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
> }
>
> 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 *mm,
> 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 *mm,
> /* 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 *mm,
> /* 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) {
> @@ -293,7 +293,7 @@ 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)) {
> diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
> index 5e39dcf23fdb..e96251853037 100644
> --- a/arch/riscv/mm/kasan_init.c
> +++ b/arch/riscv/mm/kasan_init.c
> @@ -31,7 +31,7 @@ static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned
> 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(pmd_t *pmd, unsigned long vaddr, unsigned
> 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(pud_t *pud, unsigned long vaddr, unsigned
> 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(pud_t *pud, unsigned long vaddr, unsigned
> 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(p4d_t *p4d,
> 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(p4d_t *p4d,
> 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(pgd_t *pgd,
> 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(pgd_t *pgd,
> 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(pgd_t *pgdp,
> 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(p4d_t *p4dp,
> 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(pgd_t *pgdp,
> 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_pud(p4d_t *p4dp,
> 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_p4d(pgd_t *pgdp,
> 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_pgd(pgd_t *pgdp,
> 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_populate_pud(p4d_t *p4d,
> 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_populate_p4d(pgd_t *pgd,
> 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_populate_pgd(unsigned long vaddr, unsigned long
> 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(void)
>
> /* 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(void)
>
> /* 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));
> diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
> index fc5fc4f785c4..0b5e38e018c8 100644
> --- a/arch/riscv/mm/pageattr.c
> +++ b/arch/riscv/mm/pageattr.c
> @@ -29,7 +29,7 @@ static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
> 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, unsigned long addr,
> 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, unsigned long addr,
> 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, unsigned long addr,
> 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(pud_t *pudp,
> 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(p4d_t *p4dp,
> 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(pgd_t *pgdp,
> 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;
>
> @@ -406,29 +406,29 @@ bool kernel_page_present(struct page *page)
> 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));
> }
> diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
> index fef4e7328e49..ef887efcb679 100644
> --- 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 phys, pgprot_t prot)
>
> 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 phys, pgprot_t prot)
>
> 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_struct *vma,
> 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
> --
> 2.39.2
>