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Diffstat (limited to 'arch/arm64/include/asm/pgtable.h')
-rw-r--r--arch/arm64/include/asm/pgtable.h41
1 files changed, 22 insertions, 19 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 149d05fb9421..bdcc7f1c9d06 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -42,6 +42,8 @@
#include <asm/cmpxchg.h>
#include <asm/fixmap.h>
#include <linux/mmdebug.h>
+#include <linux/mm_types.h>
+#include <linux/sched.h>
extern void __pte_error(const char *file, int line, unsigned long val);
extern void __pmd_error(const char *file, int line, unsigned long val);
@@ -149,12 +151,20 @@ static inline pte_t pte_mkwrite(pte_t pte)
static inline pte_t pte_mkclean(pte_t pte)
{
- return clear_pte_bit(pte, __pgprot(PTE_DIRTY));
+ pte = clear_pte_bit(pte, __pgprot(PTE_DIRTY));
+ pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
+
+ return pte;
}
static inline pte_t pte_mkdirty(pte_t pte)
{
- return set_pte_bit(pte, __pgprot(PTE_DIRTY));
+ pte = set_pte_bit(pte, __pgprot(PTE_DIRTY));
+
+ if (pte_write(pte))
+ pte = clear_pte_bit(pte, __pgprot(PTE_RDONLY));
+
+ return pte;
}
static inline pte_t pte_mkold(pte_t pte)
@@ -207,9 +217,6 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
}
}
-struct mm_struct;
-struct vm_area_struct;
-
extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
/*
@@ -238,7 +245,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
* hardware updates of the pte (ptep_set_access_flags safely changes
* valid ptes without going through an invalid entry).
*/
- if (pte_valid(*ptep) && pte_valid(pte)) {
+ if (IS_ENABLED(CONFIG_DEBUG_VM) && pte_valid(*ptep) && pte_valid(pte) &&
+ (mm == current->active_mm || atomic_read(&mm->mm_users) > 1)) {
VM_WARN_ONCE(!pte_young(pte),
"%s: racy access flag clearing: 0x%016llx -> 0x%016llx",
__func__, pte_val(*ptep), pte_val(pte));
@@ -641,28 +649,23 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/*
- * ptep_set_wrprotect - mark read-only while preserving the hardware update of
- * the Access Flag.
+ * ptep_set_wrprotect - mark read-only while trasferring potential hardware
+ * dirty status (PTE_DBM && !PTE_RDONLY) to the software PTE_DIRTY bit.
*/
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
{
pte_t old_pte, pte;
- /*
- * ptep_set_wrprotect() is only called on CoW mappings which are
- * private (!VM_SHARED) with the pte either read-only (!PTE_WRITE &&
- * PTE_RDONLY) or writable and software-dirty (PTE_WRITE &&
- * !PTE_RDONLY && PTE_DIRTY); see is_cow_mapping() and
- * protection_map[]. There is no race with the hardware update of the
- * dirty state: clearing of PTE_RDONLY when PTE_WRITE (a.k.a. PTE_DBM)
- * is set.
- */
- VM_WARN_ONCE(pte_write(*ptep) && !pte_dirty(*ptep),
- "%s: potential race with hardware DBM", __func__);
pte = READ_ONCE(*ptep);
do {
old_pte = pte;
+ /*
+ * If hardware-dirty (PTE_WRITE/DBM bit set and PTE_RDONLY
+ * clear), set the PTE_DIRTY bit.
+ */
+ if (pte_hw_dirty(pte))
+ pte = pte_mkdirty(pte);
pte = pte_wrprotect(pte);
pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep),
pte_val(old_pte), pte_val(pte));