[IA64] Fix convert_to_non_syscall() so gdb inferior calls work again

Fix convert_to_non_syscall() so it arranges for the kernel to be left
via ia64_leave_kernel() rather than ia64_leave_syscall().  The latter
no longer tolerates being called with pSys=0 and pNonSys=1.

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

diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index c253fd5914fcb6e4144f1bc8dc2930a22dbde161..9e730c7bf0cd6eb94237bf9ac3db4ff70443686d 100644 (file)
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -705,12 +705,32 @@ convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
                        break;
        }
 
+       /*
+        * Note: at the time of this call, the target task is blocked
+        * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL
+        * (aka, "pLvSys") we redirect execution from
+        * .work_pending_syscall_end to .work_processed_kernel.
+        */
        unw_get_pr(&prev_info, &pr);
-       pr &= ~(1UL << PRED_SYSCALL);
+       pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL));
        pr |=  (1UL << PRED_NON_SYSCALL);
        unw_set_pr(&prev_info, pr);
 
        pt->cr_ifs = (1UL << 63) | cfm;
+       /*
+        * Clear the memory that is NOT written on syscall-entry to
+        * ensure we do not leak kernel-state to user when execution
+        * resumes.
+        */
+       pt->r2 = 0;
+       pt->r3 = 0;
+       pt->r14 = 0;
+       memset(&pt->r16, 0, 16*8);      /* clear r16-r31 */
+       memset(&pt->f6, 0, 6*16);       /* clear f6-f11 */
+       pt->b7 = 0;
+       pt->ar_ccv = 0;
+       pt->ar_csd = 0;
+       pt->ar_ssd = 0;
 }
 
 static int