x86: Improve information from domain_crash_synchronous

As it currently stands, the string "domain_crash_sync called from entry.S" is
not helpful at identifying why the domain was crashed, and a debug build of
Xen doesn't help the matter

This patch improves the information printed, by pointing to where the crash
decision was made.

Specific improvements include:
 * Moving the ascii string "domain_crash_sync called from entry.S\n" away from
   some semi-hot code cache lines.
 * Moving the printk into C code (especially as this_cpu() is miserable to use
   in assembly code)
 * Undo the previous confusing situation of having the
   domain_crash_synchronous() as a macro in C code, yet a global symbol in
   assembly code.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 771e59a132..6c7bd99788 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -3748,6 +3748,17 @@ unsigned long do_get_debugreg(int reg)
     return -EINVAL;
 }
 
+void asm_domain_crash_synchronous(unsigned long addr)
+{
+    if ( addr == 0 )
+        addr = this_cpu(last_extable_addr);
+
+    printk("domain_crash_sync called from entry.S: fault at %p ", _p(addr));
+    print_symbol("%s\n", addr);
+
+    __domain_crash_synchronous();
+}
+
 /*
  * Local variables:
  * mode: C