4 files changed, 11 insertions, 5 deletions

diff --git a/arch/x86/kernel/apic_32.c b/arch/x86/kernel/apic_32.c
index d5767cb19d56..3f13a1aa07cd 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 0633cfd0dc29..5e22f8d2d507 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 3e1cecedde42..664a5db36d40 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 57a991b9c053..b69e7ba7bf1d 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} }