1 files changed, 63 insertions, 79 deletions

diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 60ee2b883797..2d37bb861faf 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -2,69 +2,82 @@
  *  User access functions based on page table walks for enhanced
  *  system layout without hardware support.
  *
- *    Copyright IBM Corp. 2006
+ *    Copyright IBM Corp. 2006, 2012
  *    Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
  */
 
 #include <linux/errno.h>
 #include <linux/hardirq.h>
 #include <linux/mm.h>
+#include <linux/hugetlb.h>
 #include <asm/uaccess.h>
 #include <asm/futex.h>
 #include "uaccess.h"
 
-static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr)
+
+/*
+ * Returns kernel address for user virtual address. If the returned address is
+ * >= -4095 (IS_ERR_VALUE(x) returns true), a fault has occured and the address
+ * contains the (negative) exception code.
+ */
+static __always_inline unsigned long follow_table(struct mm_struct *mm,
+                                                  unsigned long addr, int write)
 {
         pgd_t *pgd;
         pud_t *pud;
         pmd_t *pmd;
+        pte_t *ptep;
 
         pgd = pgd_offset(mm, addr);
         if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-                return (pte_t *) 0x3a;
+                return -0x3aUL;
 
         pud = pud_offset(pgd, addr);
         if (pud_none(*pud) || unlikely(pud_bad(*pud)))
-                return (pte_t *) 0x3b;
+                return -0x3bUL;
 
         pmd = pmd_offset(pud, addr);
-        if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
-                return (pte_t *) 0x10;
+        if (pmd_none(*pmd))
+                return -0x10UL;
+        if (pmd_huge(*pmd)) {
+                if (write && (pmd_val(*pmd) & _SEGMENT_ENTRY_RO))
+                        return -0x04UL;
+                return (pmd_val(*pmd) & HPAGE_MASK) + (addr & ~HPAGE_MASK);
+        }
+        if (unlikely(pmd_bad(*pmd)))
+                return -0x10UL;
+
+        ptep = pte_offset_map(pmd, addr);
+        if (!pte_present(*ptep))
+                return -0x11UL;
+        if (write && !pte_write(*ptep))
+                return -0x04UL;
 
-        return pte_offset_map(pmd, addr);
+        return (pte_val(*ptep) & PAGE_MASK) + (addr & ~PAGE_MASK);
 }
 
 static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
                                              size_t n, int write_user)
 {
         struct mm_struct *mm = current->mm;
-        unsigned long offset, pfn, done, size;
-        pte_t *pte;
+        unsigned long offset, done, size, kaddr;
         void *from, *to;
 
         done = 0;
 retry:
         spin_lock(&mm->page_table_lock);
         do {
-                pte = follow_table(mm, uaddr);
-                if ((unsigned long) pte < 0x1000)
+                kaddr = follow_table(mm, uaddr, write_user);
+                if (IS_ERR_VALUE(kaddr))
                         goto fault;
-                if (!pte_present(*pte)) {
-                        pte = (pte_t *) 0x11;
-                        goto fault;
-                } else if (write_user && !pte_write(*pte)) {
-                        pte = (pte_t *) 0x04;
-                        goto fault;
-                }
 
-                pfn = pte_pfn(*pte);
-                offset = uaddr & (PAGE_SIZE - 1);
+                offset = uaddr & ~PAGE_MASK;
                 size = min(n - done, PAGE_SIZE - offset);
                 if (write_user) {
-                        to = (void *)((pfn << PAGE_SHIFT) + offset);
+                        to = (void *) kaddr;
                         from = kptr + done;
                 } else {
-                        from = (void *)((pfn << PAGE_SHIFT) + offset);
+                        from = (void *) kaddr;
                         to = kptr + done;
                 }
                 memcpy(to, from, size);
@@ -75,7 +88,7 @@ retry:
         return n - done;
 fault:
         spin_unlock(&mm->page_table_lock);
-        if (__handle_fault(uaddr, (unsigned long) pte, write_user))
+        if (__handle_fault(uaddr, -kaddr, write_user))
                 return n - done;
         goto retry;
 }
@@ -84,27 +97,22 @@ fault:
  * Do DAT for user address by page table walk, return kernel address.
  * This function needs to be called with current->mm->page_table_lock held.
  */
-static __always_inline unsigned long __dat_user_addr(unsigned long uaddr)
+static __always_inline unsigned long __dat_user_addr(unsigned long uaddr,
+                                                     int write)
 {
         struct mm_struct *mm = current->mm;
-        unsigned long pfn;
-        pte_t *pte;
+        unsigned long kaddr;
         int rc;
 
 retry:
-        pte = follow_table(mm, uaddr);
-        if ((unsigned long) pte < 0x1000)
-                goto fault;
-        if (!pte_present(*pte)) {
-                pte = (pte_t *) 0x11;
+        kaddr = follow_table(mm, uaddr, write);
+        if (IS_ERR_VALUE(kaddr))
                 goto fault;
-        }
 
-        pfn = pte_pfn(*pte);
-        return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
+        return kaddr;
 fault:
         spin_unlock(&mm->page_table_lock);
-        rc = __handle_fault(uaddr, (unsigned long) pte, 0);
+        rc = __handle_fault(uaddr, -kaddr, write);
         spin_lock(&mm->page_table_lock);
         if (!rc)
                 goto retry;
@@ -159,11 +167,9 @@ static size_t clear_user_pt(size_t n, void __user *to)
 
 static size_t strnlen_user_pt(size_t count, const char __user *src)
 {
-        char *addr;
         unsigned long uaddr = (unsigned long) src;
         struct mm_struct *mm = current->mm;
-        unsigned long offset, pfn, done, len;
-        pte_t *pte;
+        unsigned long offset, done, len, kaddr;
         size_t len_str;
 
         if (segment_eq(get_fs(), KERNEL_DS))
@@ -172,19 +178,13 @@ static size_t strnlen_user_pt(size_t count, const char __user *src)
 retry:
         spin_lock(&mm->page_table_lock);
         do {
-                pte = follow_table(mm, uaddr);
-                if ((unsigned long) pte < 0x1000)
-                        goto fault;
-                if (!pte_present(*pte)) {
-                        pte = (pte_t *) 0x11;
+                kaddr = follow_table(mm, uaddr, 0);
+                if (IS_ERR_VALUE(kaddr))
                         goto fault;
-                }
 
-                pfn = pte_pfn(*pte);
-                offset = uaddr & (PAGE_SIZE-1);
-                addr = (char *)(pfn << PAGE_SHIFT) + offset;
+                offset = uaddr & ~PAGE_MASK;
                 len = min(count - done, PAGE_SIZE - offset);
-                len_str = strnlen(addr, len);
+                len_str = strnlen((char *) kaddr, len);
                 done += len_str;
                 uaddr += len_str;
         } while ((len_str == len) && (done < count));
@@ -192,7 +192,7 @@ retry:
         return done + 1;
 fault:
         spin_unlock(&mm->page_table_lock);
-        if (__handle_fault(uaddr, (unsigned long) pte, 0))
+        if (__handle_fault(uaddr, -kaddr, 0))
                 return 0;
         goto retry;
 }
@@ -225,11 +225,10 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
                               const void __user *from)
 {
         struct mm_struct *mm = current->mm;
-        unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
-                      uaddr, done, size, error_code;
+        unsigned long offset_max, uaddr, done, size, error_code;
         unsigned long uaddr_from = (unsigned long) from;
         unsigned long uaddr_to = (unsigned long) to;
-        pte_t *pte_from, *pte_to;
+        unsigned long kaddr_to, kaddr_from;
         int write_user;
 
         if (segment_eq(get_fs(), KERNEL_DS)) {
@@ -242,38 +241,23 @@ retry:
         do {
                 write_user = 0;
                 uaddr = uaddr_from;
-                pte_from = follow_table(mm, uaddr_from);
-                error_code = (unsigned long) pte_from;
-                if (error_code < 0x1000)
-                        goto fault;
-                if (!pte_present(*pte_from)) {
-                        error_code = 0x11;
+                kaddr_from = follow_table(mm, uaddr_from, 0);
+                error_code = kaddr_from;
+                if (IS_ERR_VALUE(error_code))
                         goto fault;
-                }
 
                 write_user = 1;
                 uaddr = uaddr_to;
-                pte_to = follow_table(mm, uaddr_to);
-                error_code = (unsigned long) pte_to;
-                if (error_code < 0x1000)
-                        goto fault;
-                if (!pte_present(*pte_to)) {
-                        error_code = 0x11;
+                kaddr_to = follow_table(mm, uaddr_to, 1);
+                error_code = (unsigned long) kaddr_to;
+                if (IS_ERR_VALUE(error_code))
                         goto fault;
-                } else if (!pte_write(*pte_to)) {
-                        error_code = 0x04;
-                        goto fault;
-                }
 
-                pfn_from = pte_pfn(*pte_from);
-                pfn_to = pte_pfn(*pte_to);
-                offset_from = uaddr_from & (PAGE_SIZE-1);
-                offset_to = uaddr_from & (PAGE_SIZE-1);
-                offset_max = max(offset_from, offset_to);
+                offset_max = max(uaddr_from & ~PAGE_MASK,
+                                 uaddr_to & ~PAGE_MASK);
                 size = min(n - done, PAGE_SIZE - offset_max);
 
-                memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
-                       (void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
+                memcpy((void *) kaddr_to, (void *) kaddr_from, size);
                 done += size;
                 uaddr_from += size;
                 uaddr_to += size;
@@ -282,7 +266,7 @@ retry:
         return n - done;
 fault:
         spin_unlock(&mm->page_table_lock);
-        if (__handle_fault(uaddr, error_code, write_user))
+        if (__handle_fault(uaddr, -error_code, write_user))
                 return n - done;
         goto retry;
 }
@@ -341,7 +325,7 @@ int futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
                 return __futex_atomic_op_pt(op, uaddr, oparg, old);
         spin_lock(&current->mm->page_table_lock);
         uaddr = (u32 __force __user *)
-                __dat_user_addr((__force unsigned long) uaddr);
+                __dat_user_addr((__force unsigned long) uaddr, 1);
         if (!uaddr) {
                 spin_unlock(&current->mm->page_table_lock);
                 return -EFAULT;
@@ -378,7 +362,7 @@ int futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
                 return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
         spin_lock(&current->mm->page_table_lock);
         uaddr = (u32 __force __user *)
-                __dat_user_addr((__force unsigned long) uaddr);
+                __dat_user_addr((__force unsigned long) uaddr, 1);
         if (!uaddr) {
                 spin_unlock(&current->mm->page_table_lock);
                 return -EFAULT;