[IA64] vti domain save/restore: fix stack unwinder

fix stack unwinder.
- fix find_save_locs() and unw_unwind().
  instruction pointer check should be suite for xen.
- fix unw_unwind_to_user()
  VTi domain fault handler doesn't always updatevcpu->on_stack so that
  the pUStk check fails. Add more checking to stop winding.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>

diff --git a/xen/arch/ia64/linux-xen/unwind.c b/xen/arch/ia64/linux-xen/unwind.c
index 2933a5b02fbd03ff66e65a4c3a5affb7b907587a..6c46e2b3f59f3be85ae0c2ecef4be6bcc4c7cf6a 100644 (file)
--- a/xen/arch/ia64/linux-xen/unwind.c
+++ b/xen/arch/ia64/linux-xen/unwind.c
@@ -1847,6 +1847,16 @@ run_script (struct unw_script *script, struct unw_frame_info *state)
        goto redo;
 }
 
+#ifdef XEN
+static inline int
+is_hypervisor_virt(unsigned long addr)
+{
+       return IS_VMM_ADDRESS(addr) &&
+               (HYPERVISOR_VIRT_START <= addr) &&
+               (addr < HYPERVISOR_VIRT_END);
+}
+#endif
+
 static int
 find_save_locs (struct unw_frame_info *info)
 {
@@ -1857,6 +1867,8 @@ find_save_locs (struct unw_frame_info *info)
        if ((info->ip & (local_cpu_data->unimpl_va_mask | 0xf))
 #ifndef XEN
            || info->ip < TASK_SIZE
+#else
+           || !is_hypervisor_virt(info->ip)
 #endif
                ) {
                /* don't let obviously bad addresses pollute the cache */
@@ -1915,7 +1927,11 @@ unw_unwind (struct unw_frame_info *info)
                return -1;
        }
        ip = info->ip = *info->rp_loc;
+#ifndef XEN
        if (ip < GATE_ADDR) {
+#else
+       if (!is_hypervisor_virt(info->ip)) {
+#endif
                UNW_DPRINT(2, "unwind.%s: reached user-space (ip=0x%lx)\n", __FUNCTION__, ip);
                STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
                return -1;
@@ -1993,6 +2009,21 @@ unw_unwind_to_user (struct unw_frame_info *info)
                if (unw_is_intr_frame(info) &&
                    (pr & (1UL << PRED_USER_STACK)))
                        return 0;
+#ifdef XEN
+               /*
+                * vmx fault handlers don't always update vcpu->on_stack
+                * so that the above (pr & (1UL << PRED_USER_STACK)) condition
+                * isn't always true.
+                * hypercall path of break_fault does set pUStk=1,
+                * other fault paths don't set.
+                *
+                * we need to stop unwinding somehow.
+                */
+               if (unw_is_intr_frame(info) &&
+                   info->task->domain->arch.is_vti &&
+                   info->pr_loc == &vcpu_regs(info->task)->pr)
+                       return 0;
+#endif
                if (unw_get_pr (info, &pr) < 0) {
                        unw_get_rp(info, &ip);
                        UNW_DPRINT(0, "unwind.%s: failed to read "