Commit 9635b47d authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
Browse files

[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: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarEric Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8f43d03f

arch/i386/kernel/apic.c

+5 −20
Original line number Diff line number Diff line
@@ -40,6 +40,11 @@ 


#include "io_ports.h"



/*

 * Knob to control our willingness to enable the local APIC.

 */

int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */



/*

 * Debug level

 */
@@ -666,26 +671,6 @@ static void apic_pm_activate(void) { } 
 * Original code written by Keir Fraser.

 */



/*

 * Knob to control our willingness to enable the local APIC.

 */

int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */



static int __init lapic_disable(char *str)

{

	enable_local_apic = -1;

	clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);

	return 0;

}

__setup("nolapic", lapic_disable);



static int __init lapic_enable(char *str)

{

	enable_local_apic = 1;

	return 0;

}

__setup("lapic", lapic_enable);



static int __init apic_set_verbosity(char *str)

{

	if (strcmp("debug", str) == 0)

arch/i386/kernel/setup.c

+11 −0
Original line number Diff line number Diff line
@@ -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.

include/asm-i386/apic.h

+13 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/pm.h>

#include <asm/fixmap.h>

#include <asm/apicdef.h>

#include <asm/processor.h>

#include <asm/system.h>



#define Dprintk(x...)
@@ -16,8 +17,20 @@ 
#define APIC_VERBOSE 1

#define APIC_DEBUG   2



extern int enable_local_apic;

extern int apic_verbosity;



static inline void lapic_disable(void)

{

	enable_local_apic = -1;

	clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);

}



static inline void lapic_enable(void)

{

	enable_local_apic = 1;

}



/*

 * Define the default level of output to be very little

 * This can be turned up by using apic=verbose for more