From: George Dunlap <george.dunlap@eu.citrix.com>
Date: Fri, 1 Jul 2011 19:31:18 +0000 (+0100)
Subject: xentrace: Allow tracing to be enabled at boot
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~10086
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=0bb1c9cd22855b9986c60ace1959ef029c5e0ce0;p=xen.git

xentrace: Allow tracing to be enabled at boot

Add a "tevt_mask" parameter to the xen command-line, allowing
trace records to be gathered early in boot.  They will be placed
into the trace buffers, and read when the user runs "xentrace".

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
---

diff --git a/xen/common/trace.c b/xen/common/trace.c
index 6e5c1d8e4b..c3ffb6d06f 100644
--- a/xen/common/trace.c
+++ b/xen/common/trace.c
@@ -45,7 +45,9 @@ CHECK_t_buf;
 
 /* opt_tbuf_size: trace buffer size (in pages) for each cpu */
 static unsigned int opt_tbuf_size;
+static unsigned int opt_tevt_mask;
 integer_param("tbuf_size", opt_tbuf_size);
+integer_param("tevt_mask", opt_tevt_mask);
 
 /* Pointers to the meta-data objects for all system trace buffers */
 static struct t_info *t_info;
@@ -338,11 +340,21 @@ void __init init_trace_bufs(void)
 {
     register_cpu_notifier(&cpu_nfb);
 
-    if ( opt_tbuf_size && alloc_trace_bufs(opt_tbuf_size) )
+    if ( opt_tbuf_size )
     {
-        printk(XENLOG_INFO "xentrace: allocation size %d failed, disabling\n",
-               opt_tbuf_size);
-        opt_tbuf_size = 0;
+        if ( alloc_trace_bufs(opt_tbuf_size) )
+        {
+            printk("xentrace: allocation size %d failed, disabling\n",
+                   opt_tbuf_size);
+            opt_tbuf_size = 0;
+        }
+        else if ( opt_tevt_mask )
+        {
+            printk("xentrace: Starting tracing, enabling mask %x\n",
+                   opt_tevt_mask);
+            tb_event_mask = opt_tevt_mask;
+            tb_init_done=1;
+        }
     }
 }