x86, xen: record and display initiator of each multicall when debugging

Store the caller for each multicall so we can report it on failure.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index c738644b543502d6577ee07b42c25f6e52493131..82f2513e975809908528db6c61f1752696eb5d06 100644 (file)
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -39,6 +39,7 @@ struct mc_buffer {
        struct multicall_entry entries[MC_BATCH];
 #if MC_DEBUG
        struct multicall_entry debug[MC_BATCH];
+       void *caller[MC_BATCH];
 #endif
        unsigned char args[MC_ARGS];
        struct callback {
@@ -154,11 +155,12 @@ void xen_mc_flush(void)
                               ret, smp_processor_id());
                        dump_stack();
                        for (i = 0; i < b->mcidx; i++) {
-                               printk(KERN_DEBUG "  call %2d/%d: op=%lu arg=[%lx] result=%ld\n",
+                               printk(KERN_DEBUG "  call %2d/%d: op=%lu arg=[%lx] result=%ld\t%pF\n",
                                       i+1, b->mcidx,
                                       b->debug[i].op,
                                       b->debug[i].args[0],
-                                      b->entries[i].result);
+                                      b->entries[i].result,
+                                      b->caller[i]);
                        }
                }
 #endif
@@ -197,6 +199,9 @@ struct multicall_space __xen_mc_entry(size_t args)
        }
 
        ret.mc = &b->entries[b->mcidx];
+#ifdef MC_DEBUG
+       b->caller[b->mcidx] = __builtin_return_address(0);
+#endif
        b->mcidx++;
        ret.args = &b->args[argidx];
        b->argidx = argidx + args;