mm: update ptep_modify_prot_commit to take old pte value as arg

Architectures like ppc64 require to do a conditional tlb flush based on
the old and new value of pte.  Enable that by passing old pte value as
the arg.

Link: http://lkml.kernel.org/r/20190116085035.29729-3-aneesh.kumar@linux.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/s390/include/asm/pgtable.h

@@ -1070,7 +1070,8 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 
 #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *);
-void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long, pte_t *, pte_t);
+void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
+			     pte_t *, pte_t, pte_t);
 
 #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
 static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,

arch/s390/mm/pgtable.c

@@ -321,7 +321,7 @@ pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr,
 }
 
 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
-			     pte_t *ptep, pte_t pte)
+			     pte_t *ptep, pte_t old_pte, pte_t pte)
 {
 	pgste_t pgste;
 	struct mm_struct *mm = vma->vm_mm;

arch/x86/include/asm/paravirt.h

@@ -433,7 +433,7 @@ static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned
 }
 
 static inline void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
-					   pte_t *ptep, pte_t pte)
+					   pte_t *ptep, pte_t old_pte, pte_t pte)
 {
 
 	if (sizeof(pteval_t) > sizeof(long))

fs/proc/task_mmu.c

@@ -948,10 +948,12 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
 	pte_t ptent = *pte;
 
 	if (pte_present(ptent)) {
-		ptent = ptep_modify_prot_start(vma, addr, pte);
-		ptent = pte_wrprotect(ptent);
+		pte_t old_pte;
+
+		old_pte = ptep_modify_prot_start(vma, addr, pte);
+		ptent = pte_wrprotect(old_pte);
 		ptent = pte_clear_soft_dirty(ptent);
-		ptep_modify_prot_commit(vma, addr, pte, ptent);
+		ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
 	} else if (is_swap_pte(ptent)) {
 		ptent = pte_swp_clear_soft_dirty(ptent);
 		set_pte_at(vma->vm_mm, addr, pte, ptent);

include/asm-generic/pgtable.h

@@ -657,7 +657,7 @@ static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
  */
 static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
 					   unsigned long addr,
-					   pte_t *ptep, pte_t pte)
+					   pte_t *ptep, pte_t old_pte, pte_t pte)
 {
 	__ptep_modify_prot_commit(vma, addr, ptep, pte);
 }

mm/memory.c

@@ -3599,7 +3599,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	int last_cpupid;
 	int target_nid;
 	bool migrated = false;
-	pte_t pte;
+	pte_t pte, old_pte;
 	bool was_writable = pte_savedwrite(vmf->orig_pte);
 	int flags = 0;
 
@@ -3619,12 +3619,12 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	 * Make it present again, Depending on how arch implementes non
 	 * accessible ptes, some can allow access by kernel mode.
 	 */
-	pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
-	pte = pte_modify(pte, vma->vm_page_prot);
+	old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
+	pte = pte_modify(old_pte, vma->vm_page_prot);
 	pte = pte_mkyoung(pte);
 	if (was_writable)
 		pte = pte_mkwrite(pte);
-	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, pte);
+	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
 	update_mmu_cache(vma, vmf->address, vmf->pte);
 
 	page = vm_normal_page(vma, vmf->address, pte);

mm/mprotect.c

@@ -110,8 +110,8 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 					continue;
 			}
 
-			ptent = ptep_modify_prot_start(vma, addr, pte);
-			ptent = pte_modify(ptent, newprot);
+			oldpte = ptep_modify_prot_start(vma, addr, pte);
+			ptent = pte_modify(oldpte, newprot);
 			if (preserve_write)
 				ptent = pte_mk_savedwrite(ptent);
 
@@ -121,7 +121,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 					 !(vma->vm_flags & VM_SOFTDIRTY))) {
 				ptent = pte_mkwrite(ptent);
 			}
-			ptep_modify_prot_commit(vma, addr, pte, ptent);
+			ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
 			pages++;
 		} else if (IS_ENABLED(CONFIG_MIGRATION)) {
 			swp_entry_t entry = pte_to_swp_entry(oldpte);