From: kfraser@localhost.localdomain <kfraser@localhost.localdomain>
Date: Mon, 10 Sep 2007 16:49:58 +0000 (+0100)
Subject: x86: Handle 'self-IPI' on legacy UP systems with no APIC.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~14984^2~1
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=78569aa816df0cccdb0c8d7e5359a85e66337265;p=xen.git

x86: Handle 'self-IPI' on legacy UP systems with no APIC.
Signed-off-by: Keir Fraser <keir@xensource.com>
---

diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index 31fc8adbe6..1d83a3aba3 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -279,6 +279,19 @@ int on_selected_cpus(
 
     ASSERT(local_irq_is_enabled());
 
+    /* Legacy UP system with no APIC to deliver IPIs? */
+    if ( unlikely(!cpu_has_apic) )
+    {
+        ASSERT(num_online_cpus() == 1);
+        if ( cpu_isset(0, selected) )
+        {
+            local_irq_disable();
+            func(info);
+            local_irq_enable();
+        }
+        return 0;
+    }
+
     if ( nr_cpus == 0 )
         return 0;