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Message-Id: <20240508191931.46060-12-alexghiti@rivosinc.com>
Date: Wed, 8 May 2024 21:19:30 +0200
From: Alexandre Ghiti <alexghiti@...osinc.com>
To: Ryan Roberts <ryan.roberts@....com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Alexander Potapenko <glider@...gle.com>,
Marco Elver <elver@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Ard Biesheuvel <ardb@...nel.org>,
Anup Patel <anup@...infault.org>,
Atish Patra <atishp@...shpatra.org>,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
kasan-dev@...glegroups.com,
linux-riscv@...ts.infradead.org,
linux-efi@...r.kernel.org,
kvm@...r.kernel.org,
kvm-riscv@...ts.infradead.org,
linux-mm@...ck.org
Cc: Alexandre Ghiti <alexghiti@...osinc.com>
Subject: [PATCH 11/12] mm, riscv, arm64: Use common ptep_set_wrprotect()/wrprotect_ptes() functions
Make riscv use the contpte aware ptep_set_wrprotect()/wrprotect_ptes()
function from arm64.
Signed-off-by: Alexandre Ghiti <alexghiti@...osinc.com>
---
arch/arm64/include/asm/pgtable.h | 56 ++++++------------------
arch/arm64/mm/contpte.c | 18 --------
arch/riscv/include/asm/pgtable.h | 25 +++++++++--
include/linux/contpte.h | 2 +
mm/contpte.c | 75 +++++++++++++++++++++++++++++++-
5 files changed, 110 insertions(+), 66 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 6591aab11c67..162efd9647dd 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1208,7 +1208,11 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline void ___ptep_set_wrprotect(struct mm_struct *mm,
+/*
+ * __ptep_set_wrprotect - mark read-only while trasferring potential hardware
+ * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit.
+ */
+static inline void __ptep_set_wrprotect(struct mm_struct *mm,
unsigned long address, pte_t *ptep,
pte_t pte)
{
@@ -1222,23 +1226,13 @@ static inline void ___ptep_set_wrprotect(struct mm_struct *mm,
} while (pte_val(pte) != pte_val(old_pte));
}
-/*
- * __ptep_set_wrprotect - mark read-only while trasferring potential hardware
- * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit.
- */
-static inline void __ptep_set_wrprotect(struct mm_struct *mm,
- unsigned long address, pte_t *ptep)
-{
- ___ptep_set_wrprotect(mm, address, ptep, __ptep_get(ptep));
-}
-
static inline void __wrprotect_ptes(struct mm_struct *mm, unsigned long address,
pte_t *ptep, unsigned int nr)
{
unsigned int i;
for (i = 0; i < nr; i++, address += PAGE_SIZE, ptep++)
- __ptep_set_wrprotect(mm, address, ptep);
+ __ptep_set_wrprotect(mm, address, ptep, __ptep_get(ptep));
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -1246,7 +1240,7 @@ static inline void __wrprotect_ptes(struct mm_struct *mm, unsigned long address,
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
unsigned long address, pmd_t *pmdp)
{
- __ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
+ __ptep_set_wrprotect(mm, address, (pte_t *)pmdp, __ptep_get((pte_t *)pmdp));
}
#define pmdp_establish pmdp_establish
@@ -1389,8 +1383,6 @@ extern void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr,
extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
unsigned int nr, int full);
-extern void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, unsigned int nr);
#define pte_batch_hint pte_batch_hint
static inline unsigned int pte_batch_hint(pte_t *ptep, pte_t pte)
@@ -1478,35 +1470,12 @@ extern int ptep_clear_flush_young(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep);
#define wrprotect_ptes wrprotect_ptes
-static __always_inline void wrprotect_ptes(struct mm_struct *mm,
- unsigned long addr, pte_t *ptep, unsigned int nr)
-{
- if (likely(nr == 1)) {
- /*
- * Optimization: wrprotect_ptes() can only be called for present
- * ptes so we only need to check contig bit as condition for
- * unfold, and we can remove the contig bit from the pte we read
- * to avoid re-reading. This speeds up fork() which is sensitive
- * for order-0 folios. Equivalent to contpte_try_unfold().
- */
- pte_t orig_pte = __ptep_get(ptep);
-
- if (unlikely(pte_cont(orig_pte))) {
- __contpte_try_unfold(mm, addr, ptep, orig_pte);
- orig_pte = pte_mknoncont(orig_pte);
- }
- ___ptep_set_wrprotect(mm, addr, ptep, orig_pte);
- } else {
- contpte_wrprotect_ptes(mm, addr, ptep, nr);
- }
-}
+extern void wrprotect_ptes(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep, unsigned int nr);
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
-static inline void ptep_set_wrprotect(struct mm_struct *mm,
- unsigned long addr, pte_t *ptep)
-{
- wrprotect_ptes(mm, addr, ptep, 1);
-}
+extern void ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
extern int ptep_set_access_flags(struct vm_area_struct *vma,
@@ -1528,7 +1497,8 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma,
#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
#define ptep_clear_flush_young __ptep_clear_flush_young
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
-#define ptep_set_wrprotect __ptep_set_wrprotect
+#define ptep_set_wrprotect(mm, addr, ptep) \
+ __ptep_set_wrprotect(mm, addr, ptep, __ptep_get(ptep))
#define wrprotect_ptes __wrprotect_ptes
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
#define ptep_set_access_flags __ptep_set_access_flags
diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index 5675a61452ac..1cef93b15d6e 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -44,21 +44,3 @@ pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm,
return __get_and_clear_full_ptes(mm, addr, ptep, nr, full);
}
EXPORT_SYMBOL_GPL(contpte_get_and_clear_full_ptes);
-
-void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, unsigned int nr)
-{
- /*
- * If wrprotecting an entire contig range, we can avoid unfolding. Just
- * set wrprotect and wait for the later mmu_gather flush to invalidate
- * the tlb. Until the flush, the page may or may not be wrprotected.
- * After the flush, it is guaranteed wrprotected. If it's a partial
- * range though, we must unfold, because we can't have a case where
- * CONT_PTE is set but wrprotect applies to a subset of the PTEs; this
- * would cause it to continue to be unpredictable after the flush.
- */
-
- contpte_try_unfold_partial(mm, addr, ptep, nr);
- __wrprotect_ptes(mm, addr, ptep, nr);
-}
-EXPORT_SYMBOL_GPL(contpte_wrprotect_ptes);
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index b151a5aa4de8..728f31da5e6a 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -755,11 +755,21 @@ static inline pte_t __ptep_get_and_clear(struct mm_struct *mm,
}
static inline void __ptep_set_wrprotect(struct mm_struct *mm,
- unsigned long address, pte_t *ptep)
+ unsigned long address, pte_t *ptep,
+ pte_t pte)
{
atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep);
}
+static inline void __wrprotect_ptes(struct mm_struct *mm, unsigned long address,
+ pte_t *ptep, unsigned int nr)
+{
+ unsigned int i;
+
+ for (i = 0; i < nr; i++, address += PAGE_SIZE, ptep++)
+ __ptep_set_wrprotect(mm, address, ptep, __ptep_get(ptep));
+}
+
static inline int __ptep_clear_flush_young(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep)
{
@@ -807,6 +817,12 @@ extern int ptep_clear_flush_young(struct vm_area_struct *vma,
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_SET_WRPROTECT
+extern void ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+extern void wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned int nr);
+#define wrprotect_ptes wrprotect_ptes
#else /* CONFIG_THP_CONTPTE */
@@ -822,12 +838,13 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma,
#define ptep_clear_flush_young __ptep_clear_flush_young
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
#define ptep_set_access_flags __ptep_set_access_flags
+#define __HAVE_ARCH_PTEP_SET_WRPROTECT
+#define ptep_set_wrprotect(mm, addr, ptep) \
+ __ptep_set_wrprotect(mm, addr, ptep, __ptep_get(ptep))
+#define wrprotect_ptes __wrprotect_ptes
#endif /* CONFIG_THP_CONTPTE */
-#define __HAVE_ARCH_PTEP_SET_WRPROTECT
-#define ptep_set_wrprotect __ptep_set_wrprotect
-
#define pgprot_nx pgprot_nx
static inline pgprot_t pgprot_nx(pgprot_t _prot)
{
diff --git a/include/linux/contpte.h b/include/linux/contpte.h
index 76244b0c678a..d1439db1706c 100644
--- a/include/linux/contpte.h
+++ b/include/linux/contpte.h
@@ -26,5 +26,7 @@ int contpte_ptep_clear_flush_young(struct vm_area_struct *vma,
int contpte_ptep_set_access_flags(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t entry, int dirty);
+void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned int nr);
#endif /* _LINUX_CONTPTE_H */
diff --git a/mm/contpte.c b/mm/contpte.c
index 9cbbff1f67ad..fe36b6b1d20a 100644
--- a/mm/contpte.c
+++ b/mm/contpte.c
@@ -49,6 +49,8 @@
* - ptep_get_and_clear()
* - ptep_test_and_clear_young()
* - ptep_clear_flush_young()
+ * - wrprotect_ptes()
+ * - ptep_set_wrprotect()
*/
pte_t huge_ptep_get(pte_t *ptep)
@@ -266,7 +268,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
pte_t pte;
if (!pte_cont(__ptep_get(ptep))) {
- __ptep_set_wrprotect(mm, addr, ptep);
+ __ptep_set_wrprotect(mm, addr, ptep, __ptep_get(ptep));
return;
}
@@ -832,4 +834,75 @@ __always_inline int ptep_set_access_flags(struct vm_area_struct *vma,
return contpte_ptep_set_access_flags(vma, addr, ptep, entry, dirty);
}
+
+static void contpte_try_unfold_partial(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned int nr)
+{
+ /*
+ * Unfold any partially covered contpte block at the beginning and end
+ * of the range.
+ */
+ size_t pgsize;
+ int ncontig;
+
+ ncontig = arch_contpte_get_num_contig(mm, addr, ptep, 0, &pgsize);
+
+ if (ptep != arch_contpte_align_down(ptep) || nr < ncontig)
+ contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep));
+
+ if (ptep + nr != arch_contpte_align_down(ptep + nr)) {
+ unsigned long last_addr = addr + pgsize * (nr - 1);
+ pte_t *last_ptep = ptep + nr - 1;
+
+ contpte_try_unfold(mm, last_addr, last_ptep,
+ __ptep_get(last_ptep));
+ }
+}
+
+void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned int nr)
+{
+ /*
+ * If wrprotecting an entire contig range, we can avoid unfolding. Just
+ * set wrprotect and wait for the later mmu_gather flush to invalidate
+ * the tlb. Until the flush, the page may or may not be wrprotected.
+ * After the flush, it is guaranteed wrprotected. If it's a partial
+ * range though, we must unfold, because we can't have a case where
+ * CONT_PTE is set but wrprotect applies to a subset of the PTEs; this
+ * would cause it to continue to be unpredictable after the flush.
+ */
+
+ contpte_try_unfold_partial(mm, addr, ptep, nr);
+ __wrprotect_ptes(mm, addr, ptep, nr);
+}
+EXPORT_SYMBOL_GPL(contpte_wrprotect_ptes);
+
+__always_inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned int nr)
+{
+ if (likely(nr == 1)) {
+ /*
+ * Optimization: wrprotect_ptes() can only be called for present
+ * ptes so we only need to check contig bit as condition for
+ * unfold, and we can remove the contig bit from the pte we read
+ * to avoid re-reading. This speeds up fork() which is sensitive
+ * for order-0 folios. Equivalent to contpte_try_unfold().
+ */
+ pte_t orig_pte = __ptep_get(ptep);
+
+ if (unlikely(pte_cont(orig_pte))) {
+ __contpte_try_unfold(mm, addr, ptep, orig_pte);
+ orig_pte = pte_mknoncont(orig_pte);
+ }
+ __ptep_set_wrprotect(mm, addr, ptep, orig_pte);
+ } else {
+ contpte_wrprotect_ptes(mm, addr, ptep, nr);
+ }
+}
+
+__always_inline void ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ wrprotect_ptes(mm, addr, ptep, 1);
+}
#endif /* CONFIG_THP_CONTPTE */
--
2.39.2
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