[tip:x86/apic] x86: x2apic, IR: Clean up panic() with nox2apic boot option

[tip-bot for Suresh Siddha <suresh.b.siddha@intel.com>]

Commit-ID:  39d83a5d684a457046aa2a6dac60f105966e78e9
Gitweb:     http://git.kernel.org/tip/39d83a5d684a457046aa2a6dac60f105966e78e9
Author:     Suresh Siddha <suresh.b.siddha@intel.com>
AuthorDate: Mon, 20 Apr 2009 13:02:29 -0700
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 21 Apr 2009 09:08:26 +0200

x86: x2apic, IR: Clean up panic() with nox2apic boot option

Instead of panic() ignore the "nox2apic" boot option when BIOS
has already enabled x2apic prior to OS handover.

[ Impact: printk warning instead of panic() when BIOS has enabled x2apic already ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: dwmw2@infradead.org
Cc: Weidong Han <weidong.han@intel.com>
LKML-Reference: <20090420200450.425091000@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 arch/x86/kernel/apic/apic.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 2b30e52..d32f558 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -141,8 +141,12 @@ static int x2apic_preenabled;
 static int disable_x2apic;
 static __init int setup_nox2apic(char *str)
 {
-	if (x2apic_enabled())
-		panic("Bios already enabled x2apic, can't enforce nox2apic");
+	if (x2apic_enabled()) {
+		pr_warning("Bios already enabled x2apic, "
+			   "can't enforce nox2apic");
+		return 0;
+	}
+
 	disable_x2apic = 1;
 	setup_clear_cpu_cap(X86_FEATURE_X2APIC);
 	return 0;