[parisc-linux-cvs] clear top half of arg registers on syscall entry

[Richard Hirst]

Hi,
  On the A500 I found e2fsck crashed.  Userland calls sys_read with
a count of 0x400, but there is really 0xffffffff00000400 in the
register.  Only happens if e2fsck is built with -O2.
e2fsprogs-1.20.deb failed, e2fsprogs-1.19.deb worked.
Not obvious from the diff below, but this change is inside an
ifdef __LP64__.

Richard


Index: Makefile
===================================================================
RCS file: /home/cvs/parisc/linux/Makefile,v
retrieving revision 1.43
diff -u -r1.43 Makefile
--- Makefile    2001/05/30 17:16:29     1.43
+++ Makefile    2001/06/06 18:13:44
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 4
 SUBLEVEL = 0
-EXTRAVERSION = -pa10
+EXTRAVERSION = -pa11
 
 KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
 
Index: arch/parisc/kernel/syscall.S
===================================================================
RCS file: /home/cvs/parisc/linux/arch/parisc/kernel/syscall.S,v
retrieving revision 1.67
diff -u -r1.67 syscall.S
--- syscall.S   2001/05/17 15:04:01     1.67
+++ syscall.S   2001/06/06 18:13:45
@@ -76,6 +76,13 @@
         * whether to do narrow or wide syscalls. -PB
         */
        ssm     PSW_SM_W, %r0
+       /* The top halves of argument registers must be cleared on syscall
+        * entry.
+        */
+       depdi   0, 31, 32, %r26
+       depdi   0, 31, 32, %r25
+       depdi   0, 31, 32, %r24
+       depdi   0, 31, 32, %r23
 #endif
        mtctl   %r28,%cr31
        rsm     PSW_I, %r28                     /* no ints for a bit  */