xen/console: add comment about external console lock helper

The current console_lock_recursive_irqsave() implementation is not speculation
safe, however it's only used to prevent interleaved output.  Note this in the
function declaration in order for callers to be aware of the limitation.

No functional change.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/include/xen/console.h b/xen/include/xen/console.h
index 68759862e88d0f1a6e475a33159cec1b4ac4ad26..6dfbade3ece36352c74f1124305da945b210f2a7 100644 (file)
--- a/xen/include/xen/console.h
+++ b/xen/include/xen/console.h
@@ -20,6 +20,7 @@ void console_init_postirq(void);
 void console_endboot(void);
 int console_has(const char *device);
 
+/* Not speculation safe - only used to prevent interleaving of output. */
 unsigned long console_lock_recursive_irqsave(void);
 void console_unlock_recursive_irqrestore(unsigned long flags);
 void console_force_unlock(void);