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Subject[PATCH 02/12] mm, riscv, arm64: Use common ptep_get() function
Date
Make riscv use the contpte aware ptep_get() function from arm64.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
arch/arm64/include/asm/pgtable.h | 30 ++++++++++----------
arch/arm64/mm/contpte.c | 47 +++++---------------------------
arch/arm64/mm/hugetlbpage.c | 6 ++--
arch/riscv/include/asm/kfence.h | 4 +--
arch/riscv/include/asm/pgtable.h | 22 +++++++++++++++
arch/riscv/kernel/efi.c | 2 +-
arch/riscv/kvm/mmu.c | 16 +++++------
arch/riscv/mm/fault.c | 2 +-
arch/riscv/mm/kasan_init.c | 2 +-
arch/riscv/mm/pageattr.c | 4 +--
arch/riscv/mm/pgtable.c | 4 +--
include/linux/contpte.h | 12 ++++++++
mm/contpte.c | 45 ++++++++++++++++++++++++++++++
13 files changed, 122 insertions(+), 74 deletions(-)
create mode 100644 include/linux/contpte.h

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 1758ce71fae9..a878735deb9f 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -38,6 +38,7 @@
#include <linux/mm_types.h>
#include <linux/sched.h>
#include <linux/page_table_check.h>
+#include <linux/contpte.h>

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
@@ -1379,8 +1380,7 @@ extern void ptep_modify_prot_commit(struct vm_area_struct *vma,
extern void __contpte_try_fold(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte);
extern void __contpte_try_unfold(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte);
-extern pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte);
+ pte_t *ptep, pte_t pte);
extern pte_t contpte_ptep_get_lockless(pte_t *orig_ptep);
extern void contpte_set_ptes(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte, unsigned int nr);
@@ -1456,16 +1456,8 @@ static inline unsigned int pte_batch_hint(pte_t *ptep, pte_t pte)
* setting it in the pgtable.
*/

+extern pte_t ptep_get(pte_t *ptep);
#define ptep_get ptep_get
-static inline pte_t ptep_get(pte_t *ptep)
-{
- pte_t pte = __ptep_get(ptep);
-
- if (likely(!pte_valid_cont(pte)))
- return pte;
-
- return contpte_ptep_get(ptep, pte);
-}

#define ptep_get_lockless ptep_get_lockless
static inline pte_t ptep_get_lockless(pte_t *ptep)
@@ -1659,9 +1651,10 @@ static inline int arch_contpte_get_num_contig(struct mm_struct *mm,
* find out the number of contiguous ptes.
*/
if (size == 0)
- return find_num_contig(mm, addr, ptep, pgsize);
+ return mm ? find_num_contig(mm, addr, ptep, pgsize) : CONT_PTES;

- *pgsize = size;
+ if (pgsize)
+ *pgsize = size;

switch (size) {
#ifndef __PAGETABLE_PMD_FOLDED
@@ -1674,11 +1667,13 @@ static inline int arch_contpte_get_num_contig(struct mm_struct *mm,
contig_ptes = 1;
break;
case CONT_PMD_SIZE:
- *pgsize = PMD_SIZE;
+ if (pgsize)
+ *pgsize = PMD_SIZE;
contig_ptes = CONT_PMDS;
break;
case CONT_PTE_SIZE:
- *pgsize = PAGE_SIZE;
+ if (pgsize)
+ *pgsize = PAGE_SIZE;
contig_ptes = CONT_PTES;
break;
}
@@ -1686,6 +1681,11 @@ static inline int arch_contpte_get_num_contig(struct mm_struct *mm,
return contig_ptes;
}

+static inline pte_t *arch_contpte_align_down(pte_t *ptep)
+{
+ return PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * CONT_PTES);
+}
+
#endif /* !__ASSEMBLY__ */

#endif /* __ASM_PGTABLE_H */
diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index 1b64b4c3f8bf..d5512ebb26e9 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -21,11 +21,6 @@ static inline bool mm_is_user(struct mm_struct *mm)
return mm != &init_mm;
}

-static inline pte_t *contpte_align_down(pte_t *ptep)
-{
- return PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * CONT_PTES);
-}
-
static void contpte_try_unfold_partial(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned int nr)
{
@@ -34,10 +29,10 @@ static void contpte_try_unfold_partial(struct mm_struct *mm, unsigned long addr,
* of the range.
*/

- if (ptep != contpte_align_down(ptep) || nr < CONT_PTES)
+ if (ptep != arch_contpte_align_down(ptep) || nr < CONT_PTES)
contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep));

- if (ptep + nr != contpte_align_down(ptep + nr)) {
+ if (ptep + nr != arch_contpte_align_down(ptep + nr)) {
unsigned long last_addr = addr + PAGE_SIZE * (nr - 1);
pte_t *last_ptep = ptep + nr - 1;

@@ -54,7 +49,7 @@ static void contpte_convert(struct mm_struct *mm, unsigned long addr,
pte_t *start_ptep;
int i;

- start_ptep = ptep = contpte_align_down(ptep);
+ start_ptep = ptep = arch_contpte_align_down(ptep);
start_addr = addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);
pte = pfn_pte(ALIGN_DOWN(pte_pfn(pte), CONT_PTES), pte_pgprot(pte));

@@ -122,7 +117,7 @@ void __contpte_try_fold(struct mm_struct *mm, unsigned long addr,
prot = pte_pgprot(pte_mkold(pte_mkclean(pte)));
expected_pte = pfn_pte(pfn, prot);
orig_ptep = ptep;
- ptep = contpte_align_down(ptep);
+ ptep = arch_contpte_align_down(ptep);

for (i = 0; i < CONT_PTES; i++) {
subpte = pte_mkold(pte_mkclean(__ptep_get(ptep)));
@@ -152,34 +147,6 @@ void __contpte_try_unfold(struct mm_struct *mm, unsigned long addr,
}
EXPORT_SYMBOL_GPL(__contpte_try_unfold);

-pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte)
-{
- /*
- * Gather access/dirty bits, which may be populated in any of the ptes
- * of the contig range. We are guaranteed to be holding the PTL, so any
- * contiguous range cannot be unfolded or otherwise modified under our
- * feet.
- */
-
- pte_t pte;
- int i;
-
- ptep = contpte_align_down(ptep);
-
- for (i = 0; i < CONT_PTES; i++, ptep++) {
- pte = __ptep_get(ptep);
-
- if (pte_dirty(pte))
- orig_pte = pte_mkdirty(orig_pte);
-
- if (pte_young(pte))
- orig_pte = pte_mkyoung(orig_pte);
- }
-
- return orig_pte;
-}
-EXPORT_SYMBOL_GPL(contpte_ptep_get);
-
pte_t contpte_ptep_get_lockless(pte_t *orig_ptep)
{
/*
@@ -214,7 +181,7 @@ pte_t contpte_ptep_get_lockless(pte_t *orig_ptep)
return orig_pte;

orig_prot = pte_pgprot(pte_mkold(pte_mkclean(orig_pte)));
- ptep = contpte_align_down(orig_ptep);
+ ptep = arch_contpte_align_down(orig_ptep);
pfn = pte_pfn(orig_pte) - (orig_ptep - ptep);

for (i = 0; i < CONT_PTES; i++, ptep++, pfn++) {
@@ -312,7 +279,7 @@ int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma,
int young = 0;
int i;

- ptep = contpte_align_down(ptep);
+ ptep = arch_contpte_align_down(ptep);
addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);

for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE)
@@ -389,7 +356,7 @@ int contpte_ptep_set_access_flags(struct vm_area_struct *vma,
* faults. Avoid per-page tlb flush in __ptep_set_access_flags()
* and instead flush the whole range at the end.
*/
- ptep = contpte_align_down(ptep);
+ ptep = arch_contpte_align_down(ptep);
start_addr = addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);

for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 5869f20ca28e..083e80ac5790 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -101,12 +101,14 @@ int find_num_contig(struct mm_struct *mm, unsigned long addr,
pud_t *pudp;
pmd_t *pmdp;

- *pgsize = PAGE_SIZE;
+ if (pgsize)
+ *pgsize = PAGE_SIZE;
p4dp = p4d_offset(pgdp, addr);
pudp = pud_offset(p4dp, addr);
pmdp = pmd_offset(pudp, addr);
if ((pte_t *)pmdp == ptep) {
- *pgsize = PMD_SIZE;
+ if (pgsize)
+ *pgsize = PMD_SIZE;
return CONT_PMDS;
}
return CONT_PTES;
diff --git a/arch/riscv/include/asm/kfence.h b/arch/riscv/include/asm/kfence.h
index 7388edd88986..f303fef8591c 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(ptep_get(pte)) & ~_PAGE_PRESENT));
+ set_pte(pte, __pte(pte_val(__ptep_get(pte)) & ~_PAGE_PRESENT));
else
- set_pte(pte, __pte(pte_val(ptep_get(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.h b/arch/riscv/include/asm/pgtable.h
index 9e397935536e..8d05179f6bbe 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -299,6 +299,7 @@ static inline unsigned long pte_napot(pte_t pte)
#define pte_cont pte_napot

#define pte_valid_napot(pte) (pte_present(pte) && pte_napot(pte))
+#define pte_valid_cont pte_valid_napot

static inline pte_t pte_mknapot(pte_t pte, unsigned int order)
{
@@ -571,6 +572,17 @@ static inline int arch_contpte_get_num_contig(struct mm_struct *mm,

return size >> hugepage_shift;
}
+
+static inline pte_t *arch_contpte_align_down(pte_t *ptep)
+{
+ pte_t __pte = READ_ONCE(*ptep);
+ int ncontig;
+
+ ncontig = napot_pte_num(napot_cont_order(__pte));
+
+ return PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * ncontig);
+}
+
#endif

static inline pte_t __ptep_get(pte_t *ptep)
@@ -696,8 +708,18 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
return ptep_test_and_clear_young(vma, address, ptep);
}

+#ifdef CONFIG_THP_CONTPTE
+
+extern pte_t ptep_get(pte_t *ptep);
+#define ptep_get ptep_get
+
+#else /* CONFIG_THP_CONTPTE */
+
#define ptep_get __ptep_get
#define set_ptes __set_ptes
+
+#endif /* CONFIG_THP_CONTPTE */
+
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define ptep_get_and_clear __ptep_get_and_clear
#define pte_clear __pte_clear
diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c
index b64bf1624a05..3d2a635c69ac 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 = ptep_get(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 a9e2fd7245e1..70c6cb3864d6 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_get(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_get(ptep));
+ ptep = (pte_t *)gstage_pte_page_vaddr(__ptep_get(ptep));
ptep = &ptep[gstage_pte_index(addr, current_level)];
} else {
ptep = NULL;
@@ -149,7 +149,7 @@ static int gstage_set_pte(struct kvm *kvm, u32 level,
if (gstage_pte_leaf(ptep))
return -EEXIST;

- if (!pte_val(ptep_get(ptep))) {
+ if (!pte_val(__ptep_get(ptep))) {
if (!pcache)
return -ENOMEM;
next_ptep = kvm_mmu_memory_cache_alloc(pcache);
@@ -160,7 +160,7 @@ static int gstage_set_pte(struct kvm *kvm, u32 level,
} else {
if (gstage_pte_leaf(ptep))
return -EEXIST;
- next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(ptep));
+ next_ptep = (pte_t *)gstage_pte_page_vaddr(__ptep_get(ptep));
}

current_level--;
@@ -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_get(ptep)))
+ if (!pte_val(__ptep_get(ptep)))
return;

if (ptep_level && !gstage_pte_leaf(ptep)) {
- next_ptep = (pte_t *)gstage_pte_page_vaddr(ptep_get(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_get(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_get(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 3ba1d4dde5dd..0e08afc1fc6a 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -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(ptep_get(pte_k))) {
+ if (!pte_present(__ptep_get(pte_k))) {
no_context(regs, addr);
return;
}
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index c301c8d291d2..381d61f42ab8 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -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_get(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);
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index 410056a50aa9..98c9dc4b983c 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -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 = ptep_get(pte);
+ pte_t val = __ptep_get(pte);

val = __pte(set_pageattr_masks(pte_val(val), walk));
set_pte(pte, val);
@@ -435,5 +435,5 @@ bool kernel_page_present(struct page *page)
return true;

pte = pte_offset_kernel(pmd, addr);
- return pte_present(ptep_get(pte));
+ return pte_present(__ptep_get(pte));
}
diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
index e86df7ef193c..5756bde9eb42 100644
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c
@@ -9,7 +9,7 @@ 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))
+ if (!pte_same(__ptep_get(ptep), entry))
__set_pte_at(vma->vm_mm, ptep, entry);
/*
* update_mmu_cache will unconditionally execute, handling both
@@ -22,7 +22,7 @@ int ptep_test_and_clear_young(struct vm_area_struct *vma,
unsigned long address,
pte_t *ptep)
{
- if (!pte_young(ptep_get(ptep)))
+ if (!pte_young(__ptep_get(ptep)))
return 0;
return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
}
diff --git a/include/linux/contpte.h b/include/linux/contpte.h
new file mode 100644
index 000000000000..46acac7222ca
--- /dev/null
+++ b/include/linux/contpte.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_CONTPTE_H
+#define _LINUX_CONTPTE_H
+
+/*
+ * The contpte APIs are used to transparently manage the contiguous bit in ptes
+ * where it is possible and makes sense to do so. The PTE_CONT bit is considered
+ * a private implementation detail of the public ptep API (see below).
+ */
+pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte);
+
+#endif /* _LINUX_CONTPTE_H */
diff --git a/mm/contpte.c b/mm/contpte.c
index 15791f6d9c41..d365356bbf92 100644
--- a/mm/contpte.c
+++ b/mm/contpte.c
@@ -6,6 +6,7 @@
#include <linux/mm.h>
#include <linux/pgtable.h>
#include <linux/hugetlb.h>
+#include <linux/contpte.h>

/*
* Any arch that wants to use that needs to define:
@@ -17,6 +18,8 @@
* - __ptep_set_wrprotect()
* - pte_cont()
* - arch_contpte_get_num_contig()
+ * - pte_valid_cont()
+ * - arch_contpte_align_down()
*/

/*
@@ -28,6 +31,7 @@
* - huge_ptep_set_access_flags()
* - huge_ptep_set_wrprotect()
* - huge_ptep_clear_flush()
+ * - ptep_get()
*/

pte_t huge_ptep_get(pte_t *ptep)
@@ -270,3 +274,44 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
ncontig = arch_contpte_get_num_contig(mm, addr, ptep, 0, &pgsize);
return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
}
+
+#ifdef CONFIG_THP_CONTPTE
+pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte)
+{
+ /*
+ * Gather access/dirty bits, which may be populated in any of the ptes
+ * of the contig range. We are guaranteed to be holding the PTL, so any
+ * contiguous range cannot be unfolded or otherwise modified under our
+ * feet.
+ */
+
+ pte_t pte;
+ int i, ncontig;
+
+ ptep = arch_contpte_align_down(ptep);
+ ncontig = arch_contpte_get_num_contig(NULL, 0, ptep, 0, NULL);
+
+ for (i = 0; i < ncontig; i++, ptep++) {
+ pte = __ptep_get(ptep);
+
+ if (pte_dirty(pte))
+ orig_pte = pte_mkdirty(orig_pte);
+
+ if (pte_young(pte))
+ orig_pte = pte_mkyoung(orig_pte);
+ }
+
+ return orig_pte;
+}
+EXPORT_SYMBOL_GPL(contpte_ptep_get);
+
+__always_inline pte_t ptep_get(pte_t *ptep)
+{
+ pte_t pte = __ptep_get(ptep);
+
+ if (likely(!pte_valid_cont(pte)))
+ return pte;
+
+ return contpte_ptep_get(ptep, pte);
+}
+#endif /* CONTPTE_THP_CONTPTE */
--
2.39.2

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