Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "The main changes are relating to our handling of access/dirty bits,
  where our low-level page-table helpers could lead to stale young
  mappings and loss of the dirty bit in some cases (the latter has not
  been observed in practice, but could happen when clearing "soft-dirty"
  if we enabled that). These were posted as part of a larger series, but
  the rest of that is less urgent and needs a v2 which I'll get to
  shortly.

  In other news, we've now got a set of fixes to resolve the
  lockdep/tracing problems that have been plaguing us for a while, but
  they're still a bit "fresh" and I plan to send them to you next week
  after we've got some more confidence in them (although initial CI
  results look good).

  Summary:

   - Fix kerneldoc warnings generated by ACPI IORT code

   - Fix pte_accessible() so that access flag is ignored

   - Fix missing header #include

   - Fix loss of software dirty bit across pte_wrprotect() when HW DBM
     is enabled"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect()
  arm64: pgtable: Fix pte_accessible()
  ACPI/IORT: Fix doc warnings in iort.c
  arm64/fpsimd: add <asm/insn.h> to <asm/kprobes.h> to fix fpsimd build

2 files changed, 20 insertions, 16 deletions

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 4ff12a7adcfd..5628289b9d5e 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -115,8 +115,6 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define pte_valid(pte)		(!!(pte_val(pte) & PTE_VALID))
 #define pte_valid_not_user(pte) \
 	((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID)
-#define pte_valid_young(pte) \
-	((pte_val(pte) & (PTE_VALID | PTE_AF)) == (PTE_VALID | PTE_AF))
 #define pte_valid_user(pte) \
 	((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER))
 
@@ -124,9 +122,12 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
  * Could the pte be present in the TLB? We must check mm_tlb_flush_pending
  * so that we don't erroneously return false for pages that have been
  * remapped as PROT_NONE but are yet to be flushed from the TLB.
+ * Note that we can't make any assumptions based on the state of the access
+ * flag, since ptep_clear_flush_young() elides a DSB when invalidating the
+ * TLB.
  */
 #define pte_accessible(mm, pte)	\
-	(mm_tlb_flush_pending(mm) ? pte_present(pte) : pte_valid_young(pte))
+	(mm_tlb_flush_pending(mm) ? pte_present(pte) : pte_valid(pte))
 
 /*
  * p??_access_permitted() is true for valid user mappings (subject to the
@@ -164,13 +165,6 @@ static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t prot)
 	return pmd;
 }
 
-static inline pte_t pte_wrprotect(pte_t pte)
-{
-	pte = clear_pte_bit(pte, __pgprot(PTE_WRITE));
-	pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
-	return pte;
-}
-
 static inline pte_t pte_mkwrite(pte_t pte)
 {
 	pte = set_pte_bit(pte, __pgprot(PTE_WRITE));
@@ -196,6 +190,20 @@ static inline pte_t pte_mkdirty(pte_t pte)
 	return pte;
 }
 
+static inline pte_t pte_wrprotect(pte_t 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 = clear_pte_bit(pte, __pgprot(PTE_WRITE));
+	pte = set_pte_bit(pte, __pgprot(PTE_RDONLY));
+	return pte;
+}
+
 static inline pte_t pte_mkold(pte_t pte)
 {
 	return clear_pte_bit(pte, __pgprot(PTE_AF));
@@ -845,12 +853,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
 	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));
diff --git a/arch/arm64/include/asm/probes.h b/arch/arm64/include/asm/probes.h
index 4266262101fe..006946745352 100644
--- a/arch/arm64/include/asm/probes.h
+++ b/arch/arm64/include/asm/probes.h
@@ -7,6 +7,8 @@
 #ifndef _ARM_PROBES_H
 #define _ARM_PROBES_H
 
+#include <asm/insn.h>
+
 typedef u32 probe_opcode_t;
 typedef void (probes_handler_t) (u32 opcode, long addr, struct pt_regs *);