[S390] Add EX_TABLE for addressing exception in usercopy functions.
This patch adds an EX_TABLE entry to mvc{p|s|os} usercopy functions that
may be called with KERNEL_DS. In combination with collaborative memory
management, kernel pages marked as unused may trigger an adressing exception
in the usercopy functions. This fixes an unhandled addressing exception bug
where strncpy_from_user() is used with len > strnlen and KERNEL_DS, crossing
a page boundary to an unused page.
Signed-off-by: Gerald Schaefer <gerald.schaefer@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 d2ffbad..07deaee 100644
--- a/arch/s390/lib/uaccess_std.c
+++ b/arch/s390/lib/uaccess_std.c
@@ -36,12 +36,12 @@
tmp1 = -256UL;
asm volatile(
"0: mvcp 0(%0,%2),0(%1),%3\n"
- " jz 8f\n"
+ "10:jz 8f\n"
"1:"ALR" %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"2: mvcp 0(%0,%2),0(%1),%3\n"
- " jnz 1b\n"
+ "11:jnz 1b\n"
" j 8f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
" "LHI" %3,-4096\n"
@@ -50,7 +50,7 @@
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"4: mvcp 0(%4,%2),0(%1),%3\n"
- " "SLR" %0,%4\n"
+ "12:"SLR" %0,%4\n"
" "ALR" %2,%4\n"
"5:"LHI" %4,-1\n"
" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
@@ -65,6 +65,7 @@
"8:"SLR" %0,%0\n"
"9: \n"
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
+ EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
@@ -85,12 +86,12 @@
tmp1 = -256UL;
asm volatile(
"0: mvcs 0(%0,%1),0(%2),%3\n"
- " jz 5f\n"
+ "7: jz 5f\n"
"1:"ALR" %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"2: mvcs 0(%0,%1),0(%2),%3\n"
- " jnz 1b\n"
+ "8: jnz 1b\n"
" j 5f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
" "LHI" %3,-4096\n"
@@ -99,11 +100,12 @@
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
"4: mvcs 0(%4,%1),0(%2),%3\n"
- " "SLR" %0,%4\n"
+ "9:"SLR" %0,%4\n"
" j 6f\n"
"5:"SLR" %0,%0\n"
"6: \n"
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
+ EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;