[IA64] ptrace and restore_sigcontext() allow ar.rsc.pl==0

This patch fixes handling of accesses to ar.rsc via ptrace & restore_sigcontext
[With Thanks to Chris Wright for noticing the restore_sigcontext path]

Signed-off-by: Matthew Chapman <matthewc@hp.com>
Acked-by: David Mosberger <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 499b7e5317cf..edd9f07860b2 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -94,7 +94,7 @@ sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
 static long
 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
 {
-        unsigned long ip, flags, nat, um, cfm;
+        unsigned long ip, flags, nat, um, cfm, rsc;
         long err;
 
         /* Always make any pending restarted system calls return -EINTR */
@@ -106,7 +106,7 @@ restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
         err |= __get_user(ip, &sc->sc_ip);                      /* instruction pointer */
         err |= __get_user(cfm, &sc->sc_cfm);
         err |= __get_user(um, &sc->sc_um);                      /* user mask */
-        err |= __get_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
+        err |= __get_user(rsc, &sc->sc_ar_rsc);
         err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
         err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
         err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
@@ -119,6 +119,7 @@ restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
         err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);       /* r15 */
 
         scr->pt.cr_ifs = cfm | (1UL << 63);
+        scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
 
         /* establish new instruction pointer: */
         scr->pt.cr_iip = ip & ~0x3UL;