From: Andrew Jones <drjones@redhat.com>
Date: Mon, 16 Aug 2010 14:30:16 -0400
Subject: [xen] hv: improve backtrace support on ia64
Message-id: <1281969016-12745-3-git-send-email-drjones@redhat.com>
Patchwork-id: 27640
O-Subject: [RHEL5.6 PATCH] xen-hv: improve backtrace support on ia64
Bugzilla: 499553
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Christopher Lalancette <clalance@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

Bugzilla: 499553

Description of problem:
    Xen-ia64 cannot generate backtraces properly at some points.

Here are some causes:
    1. At some points of procedure entry, unwind info cannot be
       generated properly.
    2. BUG() doesn't show the stacktrace.

Matches upstream, tested by someone in Fujitsu and myself.
Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=2671576
---
 arch/ia64/xen/ivt.S             |    1 +
 include/asm-ia64/xenprocessor.h |    6 +++++-
 2 files changed, 6 insertions(+), 1 deletions(-)

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/arch/ia64/xen/ivt.S b/arch/ia64/xen/ivt.S
index 767b103..c7d8c3c 100644
--- a/arch/ia64/xen/ivt.S
+++ b/arch/ia64/xen/ivt.S
@@ -1237,6 +1237,7 @@ fast_hypercall:
 	nop 0
 	bsw.1					// B (6 cyc) regs are saved, switch to bank 1
 	;;
+	PT_REGS_UNWIND_INFO(-48)
 
 	ssm psr.ic | PSR_DEFAULT_BITS		// M2	now it's safe to re-enable intr.-collection
 //	movl r3=ia64_ret_from_syscall		// X
diff --git a/include/asm-ia64/xenprocessor.h b/include/asm-ia64/xenprocessor.h
index 7a38f1b..0282b06 100644
--- a/include/asm-ia64/xenprocessor.h
+++ b/include/asm-ia64/xenprocessor.h
@@ -237,6 +237,10 @@ typedef union {
     u64 itir;
 } ia64_itir_t;
 
-#define dump_execution_state() printk("FIXME: implement ia64 dump_execution_state()\n");
+#define dump_execution_state()						\
+    do {								\
+        printk("FIXME: implement ia64 dump_execution_state()\n");	\
+        dump_stack();							\
+    } while (0)
 
 #endif // _ASM_IA64_XENPROCESSOR_H