9 files changed, 88 insertions, 36 deletions

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 92fe01c355a9..11a38635dd65 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -247,8 +247,17 @@ extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 #define pmd_large(pmd)          0
 #define has_transparent_hugepage() 0
 #endif
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
                                  unsigned *shift);
+static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+                                               unsigned *shift)
+{
+        if (!arch_irqs_disabled()) {
+                pr_info("%s called with irq enabled\n", __func__);
+                dump_stack();
+        }
+        return __find_linux_pte_or_hugepte(pgdir, ea, shift);
+}
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index a4c62eb0ee48..44b480e3a5af 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -334,9 +334,11 @@ static inline unsigned long eeh_token_to_phys(unsigned long token)
         int hugepage_shift;
 
         /*
-         * We won't find hugepages here, iomem
+         * We won't find hugepages here(this is iomem). Hence we are not
+         * worried about _PAGE_SPLITTING/collapse. Also we will not hit
+         * page table free, because of init_mm.
          */
-        ptep = find_linux_pte_or_hugepte(init_mm.pgd, token, &hugepage_shift);
+        ptep = __find_linux_pte_or_hugepte(init_mm.pgd, token, &hugepage_shift);
         if (!ptep)
                 return token;
         WARN_ON(hugepage_shift);
diff --git a/arch/powerpc/kernel/io-workarounds.c b/arch/powerpc/kernel/io-workarounds.c
index 24b968f8e4d8..63d9cc4d7366 100644
--- a/arch/powerpc/kernel/io-workarounds.c
+++ b/arch/powerpc/kernel/io-workarounds.c
@@ -71,15 +71,15 @@ struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
                 vaddr = (unsigned long)PCI_FIX_ADDR(addr);
                 if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
                         return NULL;
-
-                ptep = find_linux_pte_or_hugepte(init_mm.pgd, vaddr,
+                /*
+                 * We won't find huge pages here (iomem). Also can't hit
+                 * a page table free due to init_mm
+                 */
+                ptep = __find_linux_pte_or_hugepte(init_mm.pgd, vaddr,
                                                  &hugepage_shift);
                 if (ptep == NULL)
                         paddr = 0;
                 else {
-                        /*
-                         * we don't have hugepages backing iomem
-                         */
                         WARN_ON(hugepage_shift);
                         paddr = pte_pfn(*ptep) << PAGE_SHIFT;
                 }
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 534acb3c6c3d..26df3864d85a 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -539,12 +539,13 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
                 if (!writing && hpte_is_writable(r)) {
                         unsigned int hugepage_shift;
                         pte_t *ptep, pte;
+                        unsigned long flags;
 
                         /*
                          * We need to protect against page table destruction
                          * while looking up and updating the pte.
                          */
-                        rcu_read_lock_sched();
+                        local_irq_save(flags);
                         ptep = find_linux_pte_or_hugepte(current->mm->pgd,
                                                          hva, &hugepage_shift);
                         if (ptep) {
@@ -553,7 +554,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                 if (pte_write(pte))
                                         write_ok = 1;
                         }
-                        rcu_read_unlock_sched();
+                        local_irq_restore(flags);
                 }
         }
 
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 73e083cb9f7e..f559b25de173 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -26,11 +26,14 @@ static void *real_vmalloc_addr(void *x)
 {
         unsigned long addr = (unsigned long) x;
         pte_t *p;
-
-        p = find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
+        /*
+         * assume we don't have huge pages in vmalloc space...
+         * So don't worry about THP collapse/split. Called
+         * Only in realmode, hence won't need irq_save/restore.
+         */
+        p = __find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
         if (!p || !pte_present(*p))
                 return NULL;
-        /* assume we don't have huge pages in vmalloc space... */
         addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
         return __va(addr);
 }
@@ -153,7 +156,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
         pte_t *ptep;
         unsigned int writing;
         unsigned long mmu_seq;
-        unsigned long rcbits;
+        unsigned long rcbits, irq_flags = 0;
 
         psize = hpte_page_size(pteh, ptel);
         if (!psize)
@@ -189,7 +192,16 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 
         /* Translate to host virtual address */
         hva = __gfn_to_hva_memslot(memslot, gfn);
-        ptep = find_linux_pte_or_hugepte(pgdir, hva, &hpage_shift);
+        /*
+         * If we had a page table table change after lookup, we would
+         * retry via mmu_notifier_retry.
+         */
+        if (realmode)
+                ptep = __find_linux_pte_or_hugepte(pgdir, hva, &hpage_shift);
+        else {
+                local_irq_save(irq_flags);
+                ptep = find_linux_pte_or_hugepte(pgdir, hva, &hpage_shift);
+        }
         if (ptep) {
                 pte_t pte;
                 unsigned int host_pte_size;
@@ -202,9 +214,11 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
                  * We should always find the guest page size
                  * to <= host page size, if host is using hugepage
                  */
-                if (host_pte_size < psize)
+                if (host_pte_size < psize) {
+                        if (!realmode)
+                                local_irq_restore(flags);
                         return H_PARAMETER;
-
+                }
                 pte = kvmppc_read_update_linux_pte(ptep, writing, hpage_shift);
                 if (pte_present(pte) && !pte_protnone(pte)) {
                         if (writing && !pte_write(pte))
@@ -216,6 +230,8 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
                         pa |= gpa & ~PAGE_MASK;
                 }
         }
+        if (!realmode)
+                local_irq_restore(irq_flags);
 
         ptel &= ~(HPTE_R_PP0 - psize);
         ptel |= pa;
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index a1f5b0d4b1d6..4d33e199edcc 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -338,6 +338,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
         pte_t *ptep;
         unsigned int wimg = 0;
         pgd_t *pgdir;
+        unsigned long flags;
 
         /* used to check for invalidations in progress */
         mmu_seq = kvm->mmu_notifier_seq;
@@ -468,14 +469,23 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 
 
         pgdir = vcpu_e500->vcpu.arch.pgdir;
+        /*
+         * We are just looking at the wimg bits, so we don't
+         * care much about the trans splitting bit.
+         * We are holding kvm->mmu_lock so a notifier invalidate
+         * can't run hence pfn won't change.
+         */
+        local_irq_save(flags);
         ptep = find_linux_pte_or_hugepte(pgdir, hva, NULL);
         if (ptep) {
                 pte_t pte = READ_ONCE(*ptep);
 
-                if (pte_present(pte))
+                if (pte_present(pte)) {
                         wimg = (pte_val(pte) >> PTE_WIMGE_SHIFT) &
                                 MAS2_WIMGE_MASK;
-                else {
+                        local_irq_restore(flags);
+                } else {
+                        local_irq_restore(flags);
                         pr_err_ratelimited("%s: pte not present: gfn %lx,pfn %lx\n",
                                            __func__, (long)gfn, pfn);
                         ret = -EINVAL;
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 2c2022d16059..444f7a5b859b 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1066,7 +1066,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
 #endif /* CONFIG_PPC_64K_PAGES */
 
         /* Get PTE and page size from page tables */
-        ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
+        ptep = __find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
         if (ptep == NULL || !pte_present(*ptep)) {
                 DBG_LOW(" no PTE !\n");
                 rc = 1;
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 2cb278a2f658..a9dbb27ca887 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -109,7 +109,7 @@ int pgd_huge(pgd_t pgd)
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {
         /* Only called for hugetlbfs pages, hence can ignore THP */
-        return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
+        return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
 }
 
 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
@@ -682,28 +682,35 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
         } while (addr = next, addr != end);
 }
 
+/*
+ * We are holding mmap_sem, so a parallel huge page collapse cannot run.
+ * To prevent hugepage split, disable irq.
+ */
 struct page *
 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 {
         pte_t *ptep;
         struct page *page;
         unsigned shift;
-        unsigned long mask;
+        unsigned long mask, flags;
         /*
          * Transparent hugepages are handled by generic code. We can skip them
          * here.
          */
+        local_irq_save(flags);
         ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
 
         /* Verify it is a huge page else bail. */
-        if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep))
+        if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) {
+                local_irq_restore(flags);
                 return ERR_PTR(-EINVAL);
-
+        }
         mask = (1UL << shift) - 1;
         page = pte_page(*ptep);
         if (page)
                 page += (address & mask) / PAGE_SIZE;
 
+        local_irq_restore(flags);
         return page;
 }
 
@@ -950,9 +957,12 @@ void flush_dcache_icache_hugepage(struct page *page)
  *
  * So long as we atomically load page table pointers we are safe against teardown,
  * we can follow the address down to the the page and take a ref on it.
+ * This function need to be called with interrupts disabled. We use this variant
+ * when we have MSR[EE] = 0 but the paca->soft_enabled = 1
  */
 
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
+pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+                                   unsigned *shift)
 {
         pgd_t pgd, *pgdp;
         pud_t pud, *pudp;
@@ -1031,7 +1041,7 @@ out:
                 *shift = pdshift;
         return ret_pte;
 }
-EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
+EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
 
 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
                 unsigned long end, int write, struct page **pages, int *nr)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index ead55351b254..ff09cde20cd2 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -111,41 +111,45 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
  * interrupt context, so if the access faults, we read the page tables
  * to find which page (if any) is mapped and access it directly.
  */
-static int read_user_stack_slow(void __user *ptr, void *ret, int nb)
+static int read_user_stack_slow(void __user *ptr, void *buf, int nb)
 {
+        int ret = -EFAULT;
         pgd_t *pgdir;
         pte_t *ptep, pte;
         unsigned shift;
         unsigned long addr = (unsigned long) ptr;
         unsigned long offset;
-        unsigned long pfn;
+        unsigned long pfn, flags;
         void *kaddr;
 
         pgdir = current->mm->pgd;
         if (!pgdir)
                 return -EFAULT;
 
+        local_irq_save(flags);
         ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift);
+        if (!ptep)
+                goto err_out;
         if (!shift)
                 shift = PAGE_SHIFT;
 
         /* align address to page boundary */
         offset = addr & ((1UL << shift) - 1);
-        addr -= offset;
 
-        if (ptep == NULL)
-                return -EFAULT;
-        pte = *ptep;
+        pte = READ_ONCE(*ptep);
         if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER))
-                return -EFAULT;
+                goto err_out;
         pfn = pte_pfn(pte);
         if (!page_is_ram(pfn))
-                return -EFAULT;
+                goto err_out;
 
         /* no highmem to worry about here */
         kaddr = pfn_to_kaddr(pfn);
-        memcpy(ret, kaddr + offset, nb);
-        return 0;
+        memcpy(buf, kaddr + offset, nb);
+        ret = 0;
+err_out:
+        local_irq_restore(flags);
+        return ret;
 }
 
 static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)