[PATCH v5] xen/console: print Xen version via keyhandler

[dmkhn@xxxxxxxxx]

Add Xen version printout to 'h' keyhandler output.

That is useful for debugging systems that have been left intact for a long
time.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Changes since v4:
- switched to checking build_id_len instead of build_id_p in print_build_id()
---
 xen/common/keyhandler.c    |  4 ++++
 xen/common/version.c       | 23 +++++++++++++++++++++--
 xen/drivers/char/console.c |  8 +++-----
 xen/include/xen/lib.h      |  3 +++
 4 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
index 6ea54838d4..0bb842ec00 100644
--- a/xen/common/keyhandler.c
+++ b/xen/common/keyhandler.c
@@ -129,6 +129,10 @@ static void cf_check show_handlers(unsigned char key)
     unsigned int i;
 
     printk("'%c' pressed -> showing installed handlers\n", key);
+
+    print_version();
+    print_build_id();
+
     for ( i = 0; i < ARRAY_SIZE(key_table); i++ )
         if ( key_table[i].fn )
             printk(" key '%c' (ascii '%02x') => %s\n",
diff --git a/xen/common/version.c b/xen/common/version.c
index bc3714b45f..b20754dfad 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -210,9 +210,28 @@ void __init xen_build_init(void)
         }
     }
 #endif /* CONFIG_X86 */
-    if ( !rc )
-        printk(XENLOG_INFO "build-id: %*phN\n", build_id_len, build_id_p);
 }
+
+void print_version(void)
+{
+    printk("Xen version %d.%d%s (%s@%s) (%s) %s %s\n",
+           xen_major_version(), xen_minor_version(), xen_extra_version(),
+           xen_compile_by(), xen_compile_domain(), xen_compiler(),
+           xen_build_info(), xen_compile_date());
+
+    printk("Latest ChangeSet: %s\n", xen_changeset());
+}
+
+void print_build_id(void)
+{
+    /*
+     * NB: build_id_len may be 0 if XEN_HAS_BUILD_ID=n.
+     * Do not print empty build-id.
+     */
+    if ( build_id_len )
+        printk("build-id: %*phN\n", build_id_len, build_id_p);
+}
+
 #endif /* BUILD_ID */
 /*
  * Local variables:
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 07b14b7b3f..2e23910dfa 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -1020,14 +1020,12 @@ void __init console_init_preirq(void)
     nrspin_lock(&console_lock);
     __putstr(xen_banner());
     nrspin_unlock(&console_lock);
-    printk("Xen version %d.%d%s (%s@%s) (%s) %s %s\n",
-           xen_major_version(), xen_minor_version(), xen_extra_version(),
-           xen_compile_by(), xen_compile_domain(), xen_compiler(),
-           xen_build_info(), xen_compile_date());
-    printk("Latest ChangeSet: %s\n", xen_changeset());
+
+    print_version();
 
     /* Locate and print the buildid, if applicable. */
     xen_build_init();
+    print_build_id();
 
     if ( opt_sync_console )
     {
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 81b722ea3e..686899a63e 100644
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -47,6 +47,9 @@ int parse_signed_integer(const char *name, const char *s, 
const char *e,
  */
 int cmdline_strcmp(const char *frag, const char *name);
 
+void print_version(void);
+void print_build_id(void);
+
 #ifdef CONFIG_DEBUG_TRACE
 extern void debugtrace_dump(void);
 extern void debugtrace_printk(const char *fmt, ...)
-- 
2.34.1