The __access_ok macro in include/asm-mips64/uaccess.h need to be changed
in order to work correctly, it's a copy from the 32-bit kernel.
It's not good enough to simply check for the "sign bit" of the address.
The area between USEG (XUSEG) and KSEG0 will in 64-bit addressing mode
generate an address error, if
accessed. The size of the area depend on the number of virtual
addressing bits, implemented in the CPU.
I have tried to come up with a patch, please see below. Any thought ?
I also changed the macro in arch/mips64/kernel/unaligned.c
/Carsten
Index: include/asm-mips64//uaccess.h
===================================================================
RCS file:
/home/repository/sw/linux-2.4.18/include/asm-mips64/uaccess.h,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 uaccess.h
--- include/asm-mips64//uaccess.h 4 Mar 2002 11:13:26 -0000
1.1.1.1
+++ include/asm-mips64//uaccess.h 17 Jun 2002 11:35:32 -0000
@@ -12,6 +12,8 @@
#include <linux/errno.h>
#include <linux/sched.h>
+#include <asm/addrspace.h>
+
#define STR(x) __STR(x)
#define __STR(x) #x
@@ -40,16 +42,23 @@
* than tests.
*
* Address valid if:
- * - "addr" doesn't have any high-bits set
- * - AND "size" doesn't have any high-bits set
- * - AND "addr+size" doesn't have any high-bits set
- * - OR we are in kernel mode.
+ * - In user mode and "addr" and "addr+size" in USEG (or XUSEG).
+ * - OR we are in kernel mode and "addr" and "addr+size" isn't in the
+ * area between USEG (XUSEG) and KSEG0.
*/
#define
__ua_size(size) \
(__builtin_constant_p(size) && (signed long) (size) > 0 ? 0 :
(size))
-#define __access_ok(addr,size,mask)
\
- (((signed long)((mask)&(addr | (addr + size) |
__ua_size(size)))) >= 0)
+static inline int
+__access_ok(unsigned long addr, unsigned long size, long mask)
+{
+ if (((mask) && ((addr | (addr+size)) >= KUSIZE)) ||
+ (((addr | (addr+size)) < K0BASE) &&
+ ((addr | (addr+size)) >= KUSIZE)))
+ return 0;
+ else
+ return 1;
+}
#define __access_mask ((long)(get_fs().seg))
Index: arch/mips64/kernel/unaligned.c
===================================================================
RCS file:
/home/repository/sw/linux-2.4.18/arch/mips64/kernel/unaligned.c,v
retrieving revision 1.2
diff -u -r1.2 unaligned.c
--- arch/mips64/kernel/unaligned.c 23 May 2002 11:11:45 -0000
1.2
+++ arch/mips64/kernel/unaligned.c 17 Jun 2002 11:51:30 -0000
@@ -89,11 +89,14 @@
#define __STR(x) #x
/*
- * User code may only access USEG; kernel code may access the
- * entire address space.
+ * User code may only access USEG;
+ * Kernel code may access the entire address space, except the area
between
+ * USEG (XUSEG) and KSEG0.
*/
-#define check_axs(pc,a,s) \
- if ((long)(~(pc) & ((a) | ((a)+(s)))) < 0) \
+#define check_axs(pc,a,s)
\
+ if (((pc < KUSIZE) && (((a) | ((a)+(s))) >= KUSIZE))
|| \
+ ((((a) | ((a)+(s))) < K0BASE) &&
\
+ (((a) | ((a)+(s))) >= KUSIZE)))
\
goto sigbus;
--
_ _ ____ ___ Carsten Langgaard Mailto:carstenl@mips.com
|\ /|||___)(___ MIPS Denmark Direct: +45 4486 5527
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TECHNOLOGIES 2750 Ballerup Fax...: +45 4486 5556
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