watchdog: Orion: Fix possible null-deference in orion_wdt_probe
[cascardo/linux.git] / mm / mprotect.c
index e8c3938..94722a4 100644 (file)
@@ -35,12 +35,16 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 }
 #endif
 
-static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
+static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                unsigned long addr, unsigned long end, pgprot_t newprot,
-               int dirty_accountable)
+               int dirty_accountable, int prot_numa, bool *ret_all_same_node)
 {
+       struct mm_struct *mm = vma->vm_mm;
        pte_t *pte, oldpte;
        spinlock_t *ptl;
+       unsigned long pages = 0;
+       bool all_same_node = true;
+       int last_nid = -1;
 
        pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
        arch_enter_lazy_mmu_mode();
@@ -48,17 +52,43 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
                oldpte = *pte;
                if (pte_present(oldpte)) {
                        pte_t ptent;
+                       bool updated = false;
 
                        ptent = ptep_modify_prot_start(mm, addr, pte);
-                       ptent = pte_modify(ptent, newprot);
+                       if (!prot_numa) {
+                               ptent = pte_modify(ptent, newprot);
+                               updated = true;
+                       } else {
+                               struct page *page;
+
+                               page = vm_normal_page(vma, addr, oldpte);
+                               if (page) {
+                                       int this_nid = page_to_nid(page);
+                                       if (last_nid == -1)
+                                               last_nid = this_nid;
+                                       if (last_nid != this_nid)
+                                               all_same_node = false;
+
+                                       /* only check non-shared pages */
+                                       if (!pte_numa(oldpte) &&
+                                           page_mapcount(page) == 1) {
+                                               ptent = pte_mknuma(ptent);
+                                               updated = true;
+                                       }
+                               }
+                       }
 
                        /*
                         * Avoid taking write faults for pages we know to be
                         * dirty.
                         */
-                       if (dirty_accountable && pte_dirty(ptent))
+                       if (dirty_accountable && pte_dirty(ptent)) {
                                ptent = pte_mkwrite(ptent);
+                               updated = true;
+                       }
 
+                       if (updated)
+                               pages++;
                        ptep_modify_prot_commit(mm, addr, pte, ptent);
                } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
                        swp_entry_t entry = pte_to_swp_entry(oldpte);
@@ -72,18 +102,40 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
                                set_pte_at(mm, addr, pte,
                                        swp_entry_to_pte(entry));
                        }
+                       pages++;
                }
        } while (pte++, addr += PAGE_SIZE, addr != end);
        arch_leave_lazy_mmu_mode();
        pte_unmap_unlock(pte - 1, ptl);
+
+       *ret_all_same_node = all_same_node;
+       return pages;
 }
 
-static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud,
-               unsigned long addr, unsigned long end, pgprot_t newprot,
-               int dirty_accountable)
+#ifdef CONFIG_NUMA_BALANCING
+static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
+                                      pmd_t *pmd)
+{
+       spin_lock(&mm->page_table_lock);
+       set_pmd_at(mm, addr & PMD_MASK, pmd, pmd_mknuma(*pmd));
+       spin_unlock(&mm->page_table_lock);
+}
+#else
+static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
+                                      pmd_t *pmd)
+{
+       BUG();
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
+               pud_t *pud, unsigned long addr, unsigned long end,
+               pgprot_t newprot, int dirty_accountable, int prot_numa)
 {
        pmd_t *pmd;
        unsigned long next;
+       unsigned long pages = 0;
+       bool all_same_node;
 
        pmd = pmd_offset(pud, addr);
        do {
@@ -91,42 +143,60 @@ static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                if (pmd_trans_huge(*pmd)) {
                        if (next - addr != HPAGE_PMD_SIZE)
                                split_huge_page_pmd(vma, addr, pmd);
-                       else if (change_huge_pmd(vma, pmd, addr, newprot))
+                       else if (change_huge_pmd(vma, pmd, addr, newprot,
+                                                prot_numa)) {
+                               pages += HPAGE_PMD_NR;
                                continue;
+                       }
                        /* fall through */
                }
                if (pmd_none_or_clear_bad(pmd))
                        continue;
-               change_pte_range(vma->vm_mm, pmd, addr, next, newprot,
-                                dirty_accountable);
+               pages += change_pte_range(vma, pmd, addr, next, newprot,
+                                dirty_accountable, prot_numa, &all_same_node);
+
+               /*
+                * If we are changing protections for NUMA hinting faults then
+                * set pmd_numa if the examined pages were all on the same
+                * node. This allows a regular PMD to be handled as one fault
+                * and effectively batches the taking of the PTL
+                */
+               if (prot_numa && all_same_node)
+                       change_pmd_protnuma(vma->vm_mm, addr, pmd);
        } while (pmd++, addr = next, addr != end);
+
+       return pages;
 }
 
-static inline void change_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
-               unsigned long addr, unsigned long end, pgprot_t newprot,
-               int dirty_accountable)
+static inline unsigned long change_pud_range(struct vm_area_struct *vma,
+               pgd_t *pgd, unsigned long addr, unsigned long end,
+               pgprot_t newprot, int dirty_accountable, int prot_numa)
 {
        pud_t *pud;
        unsigned long next;
+       unsigned long pages = 0;
 
        pud = pud_offset(pgd, addr);
        do {
                next = pud_addr_end(addr, end);
                if (pud_none_or_clear_bad(pud))
                        continue;
-               change_pmd_range(vma, pud, addr, next, newprot,
-                                dirty_accountable);
+               pages += change_pmd_range(vma, pud, addr, next, newprot,
+                                dirty_accountable, prot_numa);
        } while (pud++, addr = next, addr != end);
+
+       return pages;
 }
 
-static void change_protection(struct vm_area_struct *vma,
+static unsigned long change_protection_range(struct vm_area_struct *vma,
                unsigned long addr, unsigned long end, pgprot_t newprot,
-               int dirty_accountable)
+               int dirty_accountable, int prot_numa)
 {
        struct mm_struct *mm = vma->vm_mm;
        pgd_t *pgd;
        unsigned long next;
        unsigned long start = addr;
+       unsigned long pages = 0;
 
        BUG_ON(addr >= end);
        pgd = pgd_offset(mm, addr);
@@ -135,10 +205,32 @@ static void change_protection(struct vm_area_struct *vma,
                next = pgd_addr_end(addr, end);
                if (pgd_none_or_clear_bad(pgd))
                        continue;
-               change_pud_range(vma, pgd, addr, next, newprot,
-                                dirty_accountable);
+               pages += change_pud_range(vma, pgd, addr, next, newprot,
+                                dirty_accountable, prot_numa);
        } while (pgd++, addr = next, addr != end);
-       flush_tlb_range(vma, start, end);
+
+       /* Only flush the TLB if we actually modified any entries: */
+       if (pages)
+               flush_tlb_range(vma, start, end);
+
+       return pages;
+}
+
+unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
+                      unsigned long end, pgprot_t newprot,
+                      int dirty_accountable, int prot_numa)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       unsigned long pages;
+
+       mmu_notifier_invalidate_range_start(mm, start, end);
+       if (is_vm_hugetlb_page(vma))
+               pages = hugetlb_change_protection(vma, start, end, newprot);
+       else
+               pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
+       mmu_notifier_invalidate_range_end(mm, start, end);
+
+       return pages;
 }
 
 int
@@ -213,12 +305,9 @@ success:
                dirty_accountable = 1;
        }
 
-       mmu_notifier_invalidate_range_start(mm, start, end);
-       if (is_vm_hugetlb_page(vma))
-               hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
-       else
-               change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable);
-       mmu_notifier_invalidate_range_end(mm, start, end);
+       change_protection(vma, start, end, vma->vm_page_prot,
+                         dirty_accountable, 0);
+
        vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
        vm_stat_account(mm, newflags, vma->vm_file, nrpages);
        perf_event_mmap(vma);
@@ -274,8 +363,7 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
                error = -EINVAL;
                if (!(vma->vm_flags & VM_GROWSDOWN))
                        goto out;
-       }
-       else {
+       } else {
                if (vma->vm_start > start)
                        goto out;
                if (unlikely(grows & PROT_GROWSUP)) {
@@ -291,9 +379,10 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
        for (nstart = start ; ; ) {
                unsigned long newflags;
 
-               /* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
+               /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
 
-               newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
+               newflags = vm_flags;
+               newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
 
                /* newflags >> 4 shift VM_MAY% in place of VM_% */
                if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {