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Commit b6df1b8b authored by Jack Steiner's avatar Jack Steiner Committed by Ingo Molnar
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x86: fix stack overflow for large values of MAX_APICS 



physid_mask_of_physid() causes a huge stack (12k) to be created if the
number of APICS is large. Replace physid_mask_of_physid() with a
new function that does not create large stacks. This is a problem only
on large x86_64 systems.

this paves the way to increase MAX_APICS.

Signed-off-by: default avatarJack Steiner <steiner@sgi.com>
Cc: linux-mm@kvack.org
Cc: mingo@elte.hu
Cc: tglx@linutronix.de
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d400524a

arch/x86/kernel/apic_32.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1269,7 +1269,7 @@ int __init APIC_init_uniprocessor(void) 
#ifdef CONFIG_CRASH_DUMP

#ifdef CONFIG_CRASH_DUMP

	boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id());

	boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id());

#endif

#endif

	phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);

	physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);





	setup_local_APIC();

	setup_local_APIC();

arch/x86/kernel/apic_64.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -942,7 +942,7 @@ int __init APIC_init_uniprocessor(void) 




	verify_local_APIC();

	verify_local_APIC();





	phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);

	physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);

	apic_write(APIC_ID, SET_APIC_ID(boot_cpu_physical_apicid));

	apic_write(APIC_ID, SET_APIC_ID(boot_cpu_physical_apicid));





	setup_local_APIC();

	setup_local_APIC();

arch/x86/kernel/smpboot.c

+2 −3
Original line number Original line Diff line number Diff line
@@ -1091,10 +1091,9 @@ static __init void disable_smp(void) 
	smpboot_clear_io_apic_irqs();

	smpboot_clear_io_apic_irqs();

#endif

#endif

	if (smp_found_config)

	if (smp_found_config)

		phys_cpu_present_map =

		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);

				physid_mask_of_physid(boot_cpu_physical_apicid);

	else

	else

		phys_cpu_present_map = physid_mask_of_physid(0);

		physid_set_mask_of_physid(0, &phys_cpu_present_map);

	map_cpu_to_logical_apicid();

	map_cpu_to_logical_apicid();

	cpu_set(0, per_cpu(cpu_sibling_map, 0));

	cpu_set(0, per_cpu(cpu_sibling_map, 0));

	cpu_set(0, per_cpu(cpu_core_map, 0));

	cpu_set(0, per_cpu(cpu_core_map, 0));

include/asm-x86/mpspec.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -101,6 +101,7 @@ typedef struct physid_mask physid_mask_t; 
		__physid_mask;						\

		__physid_mask;						\

	})

	})





/* Note: will create very large stack frames if physid_mask_t is big */

#define physid_mask_of_physid(physid)					\

#define physid_mask_of_physid(physid)					\

	({								\

	({								\

		physid_mask_t __physid_mask = PHYSID_MASK_NONE;		\

		physid_mask_t __physid_mask = PHYSID_MASK_NONE;		\
@@ -108,6 +109,12 @@ typedef struct physid_mask physid_mask_t; 
		__physid_mask;						\

		__physid_mask;						\

	})

	})





static inline void physid_set_mask_of_physid(int physid, physid_mask_t *map)

{

	physids_clear(*map);

	physid_set(physid, *map);

}



#define PHYSID_MASK_ALL		{ {[0 ... PHYSID_ARRAY_SIZE-1] = ~0UL} }

#define PHYSID_MASK_ALL		{ {[0 ... PHYSID_ARRAY_SIZE-1] = ~0UL} }

#define PHYSID_MASK_NONE	{ {[0 ... PHYSID_ARRAY_SIZE-1] = 0UL} }

#define PHYSID_MASK_NONE	{ {[0 ... PHYSID_ARRAY_SIZE-1] = 0UL} }