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Commit 61ec7567 authored by Len Brown's avatar Len Brown
Browse files

ACPI: boot correctly with "nosmp" or "maxcpus=0" 

In MPS mode, "nosmp" and "maxcpus=0" boot a UP kernel with IOAPIC disabled.
However, in ACPI mode, these parameters didn't completely disable
the IO APIC initialization code and boot failed.

init/main.c:
	Disable the IO_APIC if "nosmp" or "maxcpus=0"
	undefine disable_ioapic_setup() when it doesn't apply.

i386:
	delete ioapic_setup(), it was a duplicate of parse_noapic()
	delete undefinition of disable_ioapic_setup()

x86_64:
	rename disable_ioapic_setup() to parse_noapic() to match i386
	define disable_ioapic_setup() in header to match i386

http://bugzilla.kernel.org/show_bug.cgi?id=1641



Acked-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 28e8351a

Documentation/kernel-parameters.txt

+6 −9
Original line number Original line Diff line number Diff line
@@ -952,14 +952,10 @@ and is between 256 and 4096 characters. It is defined in the file 
			Format: <1-256>

			Format: <1-256>





	maxcpus=	[SMP] Maximum number of processors that	an SMP kernel

	maxcpus=	[SMP] Maximum number of processors that	an SMP kernel

			should make use of.

			should make use of.  maxcpus=n : n >= 0 limits the

			Using "nosmp" or "maxcpus=0" will disable SMP

			kernel to using 'n' processors.  n=0 is a special case,

			entirely (the MPS table probe still happens, though).

			it is equivalent to "nosmp", which also disables

			A command-line option of "maxcpus=<NUM>", where <NUM>

			the IO APIC.

			is an integer greater than 0, limits the maximum number

			of CPUs activated in SMP mode to <NUM>.

			Using "maxcpus=1" on an SMP kernel is the trivial

			case of an SMP kernel with only one CPU.





	max_addr=[KMG]	[KNL,BOOT,ia64] All physical memory greater than or

	max_addr=[KMG]	[KNL,BOOT,ia64] All physical memory greater than or

			equal to this physical address is ignored.

			equal to this physical address is ignored.
@@ -1184,7 +1180,8 @@ and is between 256 and 4096 characters. It is defined in the file 




	nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.

	nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.





	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel.

	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,

			and disable the IO APIC.  legacy for "maxcpus=0".





	nosoftlockup	[KNL] Disable the soft-lockup detector.

	nosoftlockup	[KNL] Disable the soft-lockup detector.

arch/i386/kernel/io_apic.c

+0 −8
Original line number Original line Diff line number Diff line
@@ -754,14 +754,6 @@ static int pirq_entries [MAX_PIRQS]; 
static int pirqs_enabled;

static int pirqs_enabled;

int skip_ioapic_setup;

int skip_ioapic_setup;





static int __init ioapic_setup(char *str)

{

	skip_ioapic_setup = 1;

	return 1;

}



__setup("noapic", ioapic_setup);



static int __init ioapic_pirq_setup(char *str)

static int __init ioapic_pirq_setup(char *str)

{

{

	int i, max;

	int i, max;

arch/x86_64/kernel/io_apic.c

+3 −5
Original line number Original line Diff line number Diff line
@@ -397,14 +397,12 @@ static void clear_IO_APIC (void) 
int skip_ioapic_setup;

int skip_ioapic_setup;

int ioapic_force;

int ioapic_force;





/* dummy parsing: see setup.c */

static int __init parse_noapic(char *str)



static int __init disable_ioapic_setup(char *str)

{

{

	skip_ioapic_setup = 1;

	disable_ioapic_setup();

	return 0;

	return 0;

}

}

early_param("noapic", disable_ioapic_setup);

early_param("noapic", parse_noapic);





/* Actually the next is obsolete, but keep it for paranoid reasons -AK */

/* Actually the next is obsolete, but keep it for paranoid reasons -AK */

static int __init disable_timer_pin_setup(char *arg)

static int __init disable_timer_pin_setup(char *arg)

include/asm-i386/io_apic.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -150,7 +150,6 @@ extern int (*ioapic_renumber_irq)(int ioapic, int irq); 




#else  /* !CONFIG_X86_IO_APIC */

#else  /* !CONFIG_X86_IO_APIC */

#define io_apic_assign_pci_irqs 0

#define io_apic_assign_pci_irqs 0

static inline void disable_ioapic_setup(void) { }

#endif

#endif





#endif
 
#endif

include/asm-x86_64/io_apic.h

+6 −0
Original line number Original line Diff line number Diff line
@@ -109,6 +109,12 @@ extern int mpc_default_type; 
/* 1 if "noapic" boot option passed */

/* 1 if "noapic" boot option passed */

extern int skip_ioapic_setup;

extern int skip_ioapic_setup;





static inline void disable_ioapic_setup(void)

{

	skip_ioapic_setup = 1;

}





/*

/*

 * If we use the IO-APIC for IRQ routing, disable automatic

 * If we use the IO-APIC for IRQ routing, disable automatic

 * assignment of PCI IRQ's.

 * assignment of PCI IRQ's.