[S390] Add dynamic size check for usercopy functions.
Use a wrapper for copy_to/from_user to chose the best usercopy method.
The mvcos instruction is better for sizes greater than 256 bytes, if
mvcos is not available a page table walk is better for sizes greater
than 1024 bytes. Also removed the redundant copy_to/from_user_std_small
functions.
Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/uaccess_std.c b/arch/s390/lib/uaccess_std.c
index f44f007..2d549ed 100644
--- a/arch/s390/lib/uaccess_std.c
+++ b/arch/s390/lib/uaccess_std.c
@@ -28,6 +28,9 @@
#define SLR "slgr"
#endif
+extern size_t copy_from_user_pt(size_t n, const void __user *from, void *to);
+extern size_t copy_to_user_pt(size_t n, void __user *to, const void *from);
+
size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
{
unsigned long tmp1, tmp2;
@@ -69,34 +72,11 @@
return size;
}
-size_t copy_from_user_std_small(size_t size, const void __user *ptr, void *x)
+size_t copy_from_user_std_check(size_t size, const void __user *ptr, void *x)
{
- unsigned long tmp1, tmp2;
-
- tmp1 = 0UL;
- asm volatile(
- "0: mvcp 0(%0,%2),0(%1),%3\n"
- " "SLR" %0,%0\n"
- " j 5f\n"
- "1: la %4,255(%1)\n" /* %4 = ptr + 255 */
- " "LHI" %3,-4096\n"
- " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
- " "SLR" %4,%1\n"
- " "CLR" %0,%4\n" /* copy crosses next page boundary? */
- " jnh 5f\n"
- "2: mvcp 0(%4,%2),0(%1),%3\n"
- " "SLR" %0,%4\n"
- " "ALR" %2,%4\n"
- "3:"LHI" %4,-1\n"
- " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
- " bras %3,4f\n"
- " xc 0(1,%2),0(%2)\n"
- "4: ex %4,0(%3)\n"
- "5:\n"
- EX_TABLE(0b,1b) EX_TABLE(2b,3b)
- : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
- : : "cc", "memory");
- return size;
+ if (size <= 1024)
+ return copy_from_user_std(size, ptr, x);
+ return copy_from_user_pt(size, ptr, x);
}
size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
@@ -130,28 +110,11 @@
return size;
}
-size_t copy_to_user_std_small(size_t size, void __user *ptr, const void *x)
+size_t copy_to_user_std_check(size_t size, void __user *ptr, const void *x)
{
- unsigned long tmp1, tmp2;
-
- tmp1 = 0UL;
- asm volatile(
- "0: mvcs 0(%0,%1),0(%2),%3\n"
- " "SLR" %0,%0\n"
- " j 3f\n"
- "1: la %4,255(%1)\n" /* ptr + 255 */
- " "LHI" %3,-4096\n"
- " nr %4,%3\n" /* (ptr + 255) & -4096UL */
- " "SLR" %4,%1\n"
- " "CLR" %0,%4\n" /* copy crosses next page boundary? */
- " jnh 3f\n"
- "2: mvcs 0(%4,%1),0(%2),%3\n"
- " "SLR" %0,%4\n"
- "3:\n"
- EX_TABLE(0b,1b) EX_TABLE(2b,3b)
- : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
- : : "cc", "memory");
- return size;
+ if (size <= 1024)
+ return copy_to_user_std(size, ptr, x);
+ return copy_to_user_pt(size, ptr, x);
}
size_t copy_in_user_std(size_t size, void __user *to, const void __user *from)
@@ -343,10 +306,10 @@
}
struct uaccess_ops uaccess_std = {
- .copy_from_user = copy_from_user_std,
- .copy_from_user_small = copy_from_user_std_small,
- .copy_to_user = copy_to_user_std,
- .copy_to_user_small = copy_to_user_std_small,
+ .copy_from_user = copy_from_user_std_check,
+ .copy_from_user_small = copy_from_user_std,
+ .copy_to_user = copy_to_user_std_check,
+ .copy_to_user_small = copy_to_user_std,
.copy_in_user = copy_in_user_std,
.clear_user = clear_user_std,
.strnlen_user = strnlen_user_std,
