[PATCH] kexec: x86: local apic fix

From: "Maciej W. Rozycki" <macro@linux-mips.org>

Fix a kexec problem whcih causes local APIC detection failure.

The problem is detect_init_APIC() is called early, before the command line
have been processed.  Therefore "lapic" (and "nolapic") have not been seen,
yet.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index cba67e4ba0af..f1ad9fdeaad8 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -44,6 +44,7 @@
 #include <linux/edd.h>
 #include <linux/nodemask.h>
 #include <video/edid.h>
+#include <asm/apic.h>
 #include <asm/e820.h>
 #include <asm/mpspec.h>
 #include <asm/setup.h>
@@ -835,6 +836,16 @@ static void __init parse_cmdline_early (char ** cmdline_p)
 #endif /* CONFIG_X86_LOCAL_APIC */
 #endif /* CONFIG_ACPI_BOOT */
 
+#ifdef CONFIG_X86_LOCAL_APIC
+                /* enable local APIC */
+                else if (!memcmp(from, "lapic", 5))
+                        lapic_enable();
+
+                /* disable local APIC */
+                else if (!memcmp(from, "nolapic", 6))
+                        lapic_disable();
+#endif /* CONFIG_X86_LOCAL_APIC */
+
                 /*
                  * highmem=size forces highmem to be exactly 'size' bytes.
                  * This works even on boxes that have no highmem otherwise.