From b6df1b8bc1250191cfee15627697111c1cbda53f Mon Sep 17 00:00:00 2001 From: Jack Steiner Date: Thu, 19 Jun 2008 21:51:05 -0500 Subject: [PATCH] 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: Jack Steiner Cc: linux-mm@kvack.org Cc: mingo@elte.hu Cc: tglx@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic_32.c | 2 +- arch/x86/kernel/apic_64.c | 2 +- arch/x86/kernel/smpboot.c | 5 ++--- include/asm-x86/mpspec.h | 7 +++++++ 4 files changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/apic_32.c b/arch/x86/kernel/apic_32.c index d5767cb19d..3f13a1aa07 100644 --- a/arch/x86/kernel/apic_32.c +++ b/arch/x86/kernel/apic_32.c @@ -1269,7 +1269,7 @@ int __init APIC_init_uniprocessor(void) #ifdef CONFIG_CRASH_DUMP boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id()); #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(); diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c index 0633cfd0dc..5e22f8d2d5 100644 --- a/arch/x86/kernel/apic_64.c +++ b/arch/x86/kernel/apic_64.c @@ -942,7 +942,7 @@ int __init APIC_init_uniprocessor(void) 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)); setup_local_APIC(); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 3e1cecedde..664a5db36d 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1091,10 +1091,9 @@ static __init void disable_smp(void) smpboot_clear_io_apic_irqs(); #endif if (smp_found_config) - 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); 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(); cpu_set(0, per_cpu(cpu_sibling_map, 0)); cpu_set(0, per_cpu(cpu_core_map, 0)); diff --git a/include/asm-x86/mpspec.h b/include/asm-x86/mpspec.h index 57a991b9c0..b69e7ba7bf 100644 --- a/include/asm-x86/mpspec.h +++ b/include/asm-x86/mpspec.h @@ -101,6 +101,7 @@ typedef struct physid_mask physid_mask_t; __physid_mask; \ }) +/* Note: will create very large stack frames if physid_mask_t is big */ #define physid_mask_of_physid(physid) \ ({ \ physid_mask_t __physid_mask = PHYSID_MASK_NONE; \ @@ -108,6 +109,12 @@ typedef struct physid_mask physid_mask_t; __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_NONE { {[0 ... PHYSID_ARRAY_SIZE-1] = 0UL} } -- 2.39.5