[PATCH 04/35] cpumask: centralize cpu_online_map and cpu_possible_map

From: Mike Travis
Date: Wed Oct 22 2008 - 22:10:08 EST


Each SMP arch defines these themselves. Move them to a central
location.

Two twists:
1) Some archs set possible_map to all 1, so we add a
CONFIG_INIT_ALL_POSSIBLE for this rather than break them.

2) mips and sparc32 '#define cpu_possible_map phys_cpu_present_map'.
Those archs simply have phys_cpu_present_map replaced everywhere.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

---
arch/alpha/kernel/smp.c | 5 -----
arch/arm/kernel/smp.c | 10 ----------
arch/cris/arch-v32/kernel/smp.c | 4 ----
arch/ia64/kernel/smpboot.c | 6 ------
arch/m32r/Kconfig | 1 +
arch/m32r/kernel/smpboot.c | 6 ------
arch/mips/include/asm/smp.h | 3 ---
arch/mips/kernel/smp-cmp.c | 2 +-
arch/mips/kernel/smp-mt.c | 2 +-
arch/mips/kernel/smp.c | 7 +------
arch/mips/kernel/smtc.c | 6 +++---
arch/mips/pmc-sierra/yosemite/smp.c | 6 +++---
arch/mips/sgi-ip27/ip27-smp.c | 2 +-
arch/mips/sibyte/bcm1480/smp.c | 8 ++++----
arch/mips/sibyte/sb1250/smp.c | 8 ++++----
arch/parisc/Kconfig | 1 +
arch/parisc/kernel/smp.c | 15 ---------------
arch/powerpc/kernel/smp.c | 4 ----
arch/s390/Kconfig | 1 +
arch/s390/kernel/smp.c | 6 ------
arch/sh/kernel/smp.c | 6 ------
arch/sparc/include/asm/smp_32.h | 2 --
arch/sparc/kernel/smp.c | 6 ++----
arch/sparc/kernel/sparc_ksyms.c | 4 ----
arch/sparc64/kernel/smp.c | 4 ----
arch/um/kernel/smp.c | 7 -------
arch/x86/kernel/smpboot.c | 6 ------
arch/x86/mach-voyager/voyager_smp.c | 7 -------
init/Kconfig | 9 +++++++++
kernel/cpu.c | 11 ++++++-----
30 files changed, 38 insertions(+), 127 deletions(-)

--- linux-2.6.28.orig/arch/alpha/kernel/smp.c
+++ linux-2.6.28/arch/alpha/kernel/smp.c
@@ -70,11 +70,6 @@ enum ipi_message_type {
/* Set to a secondary's cpuid when it comes online. */
static int smp_secondary_alive __devinitdata = 0;

-/* Which cpus ids came online. */
-cpumask_t cpu_online_map;
-
-EXPORT_SYMBOL(cpu_online_map);
-
int smp_num_probed; /* Internal processor count */
int smp_num_cpus = 1; /* Number that came online. */
EXPORT_SYMBOL(smp_num_cpus);
--- linux-2.6.28.orig/arch/arm/kernel/smp.c
+++ linux-2.6.28/arch/arm/kernel/smp.c
@@ -34,16 +34,6 @@
#include <asm/ptrace.h>

/*
- * bitmask of present and online CPUs.
- * The present bitmask indicates that the CPU is physically present.
- * The online bitmask indicates that the CPU is up and running.
- */
-cpumask_t cpu_possible_map;
-EXPORT_SYMBOL(cpu_possible_map);
-cpumask_t cpu_online_map;
-EXPORT_SYMBOL(cpu_online_map);
-
-/*
* as from 2.5, kernels no longer have an init_tasks structure
* so we need some other way of telling a new secondary core
* where to place its SVC stack
--- linux-2.6.28.orig/arch/cris/arch-v32/kernel/smp.c
+++ linux-2.6.28/arch/cris/arch-v32/kernel/smp.c
@@ -29,11 +29,7 @@
spinlock_t cris_atomic_locks[] = { [0 ... LOCK_COUNT - 1] = SPIN_LOCK_UNLOCKED};

/* CPU masks */
-cpumask_t cpu_online_map = CPU_MASK_NONE;
-EXPORT_SYMBOL(cpu_online_map);
cpumask_t phys_cpu_present_map = CPU_MASK_NONE;
-cpumask_t cpu_possible_map;
-EXPORT_SYMBOL(cpu_possible_map);
EXPORT_SYMBOL(phys_cpu_present_map);

/* Variables used during SMP boot */
--- linux-2.6.28.orig/arch/ia64/kernel/smpboot.c
+++ linux-2.6.28/arch/ia64/kernel/smpboot.c
@@ -131,12 +131,6 @@ struct task_struct *task_for_booting_cpu
*/
DEFINE_PER_CPU(int, cpu_state);

-/* Bitmasks of currently online, and possible CPUs */
-cpumask_t cpu_online_map;
-EXPORT_SYMBOL(cpu_online_map);
-cpumask_t cpu_possible_map = CPU_MASK_NONE;
-EXPORT_SYMBOL(cpu_possible_map);
-
cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
EXPORT_SYMBOL(cpu_core_map);
DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
--- linux-2.6.28.orig/arch/m32r/Kconfig
+++ linux-2.6.28/arch/m32r/Kconfig
@@ -10,6 +10,7 @@ config M32R
default y
select HAVE_IDE
select HAVE_OPROFILE
+ select INIT_ALL_POSSIBLE

config SBUS
bool
--- linux-2.6.28.orig/arch/m32r/kernel/smpboot.c
+++ linux-2.6.28/arch/m32r/kernel/smpboot.c
@@ -73,17 +73,11 @@ static unsigned int bsp_phys_id = -1;
/* Bitmask of physically existing CPUs */
physid_mask_t phys_cpu_present_map;

-/* Bitmask of currently online CPUs */
-cpumask_t cpu_online_map;
-EXPORT_SYMBOL(cpu_online_map);
-
cpumask_t cpu_bootout_map;
cpumask_t cpu_bootin_map;
static cpumask_t cpu_callin_map;
cpumask_t cpu_callout_map;
EXPORT_SYMBOL(cpu_callout_map);
-cpumask_t cpu_possible_map = CPU_MASK_ALL;
-EXPORT_SYMBOL(cpu_possible_map);

/* Per CPU bogomips and other parameters */
struct cpuinfo_m32r cpu_data[NR_CPUS] __cacheline_aligned;
--- linux-2.6.28.orig/arch/mips/include/asm/smp.h
+++ linux-2.6.28/arch/mips/include/asm/smp.h
@@ -38,9 +38,6 @@ extern int __cpu_logical_map[NR_CPUS];
#define SMP_RESCHEDULE_YOURSELF 0x1 /* XXX braindead */
#define SMP_CALL_FUNCTION 0x2

-extern cpumask_t phys_cpu_present_map;
-#define cpu_possible_map phys_cpu_present_map
-
extern void asmlinkage smp_bootstrap(void);

/*
--- linux-2.6.28.orig/arch/mips/kernel/smp-cmp.c
+++ linux-2.6.28/arch/mips/kernel/smp-cmp.c
@@ -226,7 +226,7 @@ void __init cmp_smp_setup(void)

for (i = 1; i < NR_CPUS; i++) {
if (amon_cpu_avail(i)) {
- cpu_set(i, phys_cpu_present_map);
+ cpu_set(i, cpu_possible_map);
__cpu_number_map[i] = ++ncpu;
__cpu_logical_map[ncpu] = i;
}
--- linux-2.6.28.orig/arch/mips/kernel/smp-mt.c
+++ linux-2.6.28/arch/mips/kernel/smp-mt.c
@@ -70,7 +70,7 @@ static unsigned int __init smvp_vpe_init
write_vpe_c0_vpeconf0(tmp);

/* Record this as available CPU */
- cpu_set(tc, phys_cpu_present_map);
+ cpu_set(tc, cpu_possible_map);
__cpu_number_map[tc] = ++ncpu;
__cpu_logical_map[ncpu] = tc;
}
--- linux-2.6.28.orig/arch/mips/kernel/smp.c
+++ linux-2.6.28/arch/mips/kernel/smp.c
@@ -44,15 +44,10 @@
#include <asm/mipsmtregs.h>
#endif /* CONFIG_MIPS_MT_SMTC */

-cpumask_t phys_cpu_present_map; /* Bitmask of available CPUs */
volatile cpumask_t cpu_callin_map; /* Bitmask of started secondaries */
-cpumask_t cpu_online_map; /* Bitmask of currently online CPUs */
int __cpu_number_map[NR_CPUS]; /* Map physical to logical */
int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */

-EXPORT_SYMBOL(phys_cpu_present_map);
-EXPORT_SYMBOL(cpu_online_map);
-
extern void cpu_idle(void);

/* Number of TCs (or siblings in Intel speak) per CPU core */
@@ -199,7 +194,7 @@ void __devinit smp_prepare_boot_cpu(void
*/
__cpu_number_map[0] = 0;
__cpu_logical_map[0] = 0;
- cpu_set(0, phys_cpu_present_map);
+ cpu_set(0, cpu_possible_map);
cpu_set(0, cpu_online_map);
cpu_set(0, cpu_callin_map);
}
--- linux-2.6.28.orig/arch/mips/kernel/smtc.c
+++ linux-2.6.28/arch/mips/kernel/smtc.c
@@ -290,7 +290,7 @@ static void smtc_configure_tlb(void)
* possibly leave some TCs/VPEs as "slave" processors.
*
* Use c0_MVPConf0 to find out how many TCs are available, setting up
- * phys_cpu_present_map and the logical/physical mappings.
+ * cpu_possible_map and the logical/physical mappings.
*/

int __init smtc_build_cpu_map(int start_cpu_slot)
@@ -304,7 +304,7 @@ int __init smtc_build_cpu_map(int start_
*/
ntcs = ((read_c0_mvpconf0() & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1;
for (i=start_cpu_slot; i<NR_CPUS && i<ntcs; i++) {
- cpu_set(i, phys_cpu_present_map);
+ cpu_set(i, cpu_possible_map);
__cpu_number_map[i] = i;
__cpu_logical_map[i] = i;
}
@@ -521,7 +521,7 @@ void smtc_prepare_cpus(int cpus)
* Pull any physically present but unused TCs out of circulation.
*/
while (tc < (((val & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1)) {
- cpu_clear(tc, phys_cpu_present_map);
+ cpu_clear(tc, cpu_possible_map);
cpu_clear(tc, cpu_present_map);
tc++;
}
--- linux-2.6.28.orig/arch/mips/pmc-sierra/yosemite/smp.c
+++ linux-2.6.28/arch/mips/pmc-sierra/yosemite/smp.c
@@ -141,7 +141,7 @@ static void __cpuinit yos_boot_secondary
}

/*
- * Detect available CPUs, populate phys_cpu_present_map before smp_init
+ * Detect available CPUs, populate cpu_possible_map before smp_init
*
* We don't want to start the secondary CPU yet nor do we have a nice probing
* feature in PMON so we just assume presence of the secondary core.
@@ -150,10 +150,10 @@ static void __init yos_smp_setup(void)
{
int i;

- cpus_clear(phys_cpu_present_map);
+ cpus_clear(cpu_possible_map);

for (i = 0; i < 2; i++) {
- cpu_set(i, phys_cpu_present_map);
+ cpu_set(i, cpu_possible_map);
__cpu_number_map[i] = i;
__cpu_logical_map[i] = i;
}
--- linux-2.6.28.orig/arch/mips/sgi-ip27/ip27-smp.c
+++ linux-2.6.28/arch/mips/sgi-ip27/ip27-smp.c
@@ -76,7 +76,7 @@ static int do_cpumask(cnodeid_t cnode, n
/* Only let it join in if it's marked enabled */
if ((acpu->cpu_info.flags & KLINFO_ENABLE) &&
(tot_cpus_found != NR_CPUS)) {
- cpu_set(cpuid, phys_cpu_present_map);
+ cpu_set(cpuid, cpu_possible_map);
alloc_cpupda(cpuid, tot_cpus_found);
cpus_found++;
tot_cpus_found++;
--- linux-2.6.28.orig/arch/mips/sibyte/bcm1480/smp.c
+++ linux-2.6.28/arch/mips/sibyte/bcm1480/smp.c
@@ -136,7 +136,7 @@ static void __cpuinit bcm1480_boot_secon

/*
* Use CFE to find out how many CPUs are available, setting up
- * phys_cpu_present_map and the logical/physical mappings.
+ * cpu_possible_map and the logical/physical mappings.
* XXXKW will the boot CPU ever not be physical 0?
*
* Common setup before any secondaries are started
@@ -145,14 +145,14 @@ static void __init bcm1480_smp_setup(voi
{
int i, num;

- cpus_clear(phys_cpu_present_map);
- cpu_set(0, phys_cpu_present_map);
+ cpus_clear(cpu_possible_map);
+ cpu_set(0, cpu_possible_map);
__cpu_number_map[0] = 0;
__cpu_logical_map[0] = 0;

for (i = 1, num = 0; i < NR_CPUS; i++) {
if (cfe_cpu_stop(i) == 0) {
- cpu_set(i, phys_cpu_present_map);
+ cpu_set(i, cpu_possible_map);
__cpu_number_map[i] = ++num;
__cpu_logical_map[num] = i;
}
--- linux-2.6.28.orig/arch/mips/sibyte/sb1250/smp.c
+++ linux-2.6.28/arch/mips/sibyte/sb1250/smp.c
@@ -124,7 +124,7 @@ static void __cpuinit sb1250_boot_second

/*
* Use CFE to find out how many CPUs are available, setting up
- * phys_cpu_present_map and the logical/physical mappings.
+ * cpu_possible_map and the logical/physical mappings.
* XXXKW will the boot CPU ever not be physical 0?
*
* Common setup before any secondaries are started
@@ -133,14 +133,14 @@ static void __init sb1250_smp_setup(void
{
int i, num;

- cpus_clear(phys_cpu_present_map);
- cpu_set(0, phys_cpu_present_map);
+ cpus_clear(cpu_possible_map);
+ cpu_set(0, cpu_possible_map);
__cpu_number_map[0] = 0;
__cpu_logical_map[0] = 0;

for (i = 1, num = 0; i < NR_CPUS; i++) {
if (cfe_cpu_stop(i) == 0) {
- cpu_set(i, phys_cpu_present_map);
+ cpu_set(i, cpu_possible_map);
__cpu_number_map[i] = ++num;
__cpu_logical_map[num] = i;
}
--- linux-2.6.28.orig/arch/parisc/Kconfig
+++ linux-2.6.28/arch/parisc/Kconfig
@@ -11,6 +11,7 @@ config PARISC
select HAVE_OPROFILE
select RTC_CLASS
select RTC_DRV_PARISC
+ select INIT_ALL_POSSIBLE
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
in many of their workstations & servers (HP9000 700 and 800 series,
--- linux-2.6.28.orig/arch/parisc/kernel/smp.c
+++ linux-2.6.28/arch/parisc/kernel/smp.c
@@ -67,21 +67,6 @@ static volatile int cpu_now_booting __re

static int parisc_max_cpus __read_mostly = 1;

-/* online cpus are ones that we've managed to bring up completely
- * possible cpus are all valid cpu
- * present cpus are all detected cpu
- *
- * On startup we bring up the "possible" cpus. Since we discover
- * CPUs later, we add them as hotplug, so the possible cpu mask is
- * empty in the beginning.
- */
-
-cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
-cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
-
-EXPORT_SYMBOL(cpu_online_map);
-EXPORT_SYMBOL(cpu_possible_map);
-
DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;

enum ipi_message_type {
--- linux-2.6.28.orig/arch/powerpc/kernel/smp.c
+++ linux-2.6.28/arch/powerpc/kernel/smp.c
@@ -60,13 +60,9 @@
int smp_hw_index[NR_CPUS];
struct thread_info *secondary_ti;

-cpumask_t cpu_possible_map = CPU_MASK_NONE;
-cpumask_t cpu_online_map = CPU_MASK_NONE;
DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;

-EXPORT_SYMBOL(cpu_online_map);
-EXPORT_SYMBOL(cpu_possible_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);

--- linux-2.6.28.orig/arch/s390/Kconfig
+++ linux-2.6.28/arch/s390/Kconfig
@@ -75,6 +75,7 @@ config S390
select HAVE_KRETPROBES
select HAVE_KVM if 64BIT
select HAVE_ARCH_TRACEHOOK
+ select INIT_ALL_POSSIBLE

source "init/Kconfig"

--- linux-2.6.28.orig/arch/s390/kernel/smp.c
+++ linux-2.6.28/arch/s390/kernel/smp.c
@@ -52,12 +52,6 @@
struct _lowcore *lowcore_ptr[NR_CPUS];
EXPORT_SYMBOL(lowcore_ptr);

-cpumask_t cpu_online_map = CPU_MASK_NONE;
-EXPORT_SYMBOL(cpu_online_map);
-
-cpumask_t cpu_possible_map = CPU_MASK_ALL;
-EXPORT_SYMBOL(cpu_possible_map);
-
static struct task_struct *current_set[NR_CPUS];

static u8 smp_cpu_type;
--- linux-2.6.28.orig/arch/sh/kernel/smp.c
+++ linux-2.6.28/arch/sh/kernel/smp.c
@@ -30,12 +30,6 @@
int __cpu_number_map[NR_CPUS]; /* Map physical to logical */
int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */

-cpumask_t cpu_possible_map;
-EXPORT_SYMBOL(cpu_possible_map);
-
-cpumask_t cpu_online_map;
-EXPORT_SYMBOL(cpu_online_map);
-
static inline void __init smp_store_cpu_info(unsigned int cpu)
{
struct sh_cpuinfo *c = cpu_data + cpu;
--- linux-2.6.28.orig/arch/sparc/include/asm/smp_32.h
+++ linux-2.6.28/arch/sparc/include/asm/smp_32.h
@@ -29,8 +29,6 @@
*/

extern unsigned char boot_cpu_id;
-extern cpumask_t phys_cpu_present_map;
-#define cpu_possible_map phys_cpu_present_map

typedef void (*smpfunc_t)(unsigned long, unsigned long, unsigned long,
unsigned long, unsigned long);
--- linux-2.6.28.orig/arch/sparc/kernel/smp.c
+++ linux-2.6.28/arch/sparc/kernel/smp.c
@@ -39,8 +39,6 @@ volatile unsigned long cpu_callin_map[NR
unsigned char boot_cpu_id = 0;
unsigned char boot_cpu_id4 = 0; /* boot_cpu_id << 2 */

-cpumask_t cpu_online_map = CPU_MASK_NONE;
-cpumask_t phys_cpu_present_map = CPU_MASK_NONE;
cpumask_t smp_commenced_mask = CPU_MASK_NONE;

/* The only guaranteed locking primitive available on all Sparc
@@ -334,7 +332,7 @@ void __init smp_setup_cpu_possible_map(v
instance = 0;
while (!cpu_find_by_instance(instance, NULL, &mid)) {
if (mid < NR_CPUS) {
- cpu_set(mid, phys_cpu_present_map);
+ cpu_set(mid, cpu_possible_map);
cpu_set(mid, cpu_present_map);
}
instance++;
@@ -354,7 +352,7 @@ void __init smp_prepare_boot_cpu(void)

current_thread_info()->cpu = cpuid;
cpu_set(cpuid, cpu_online_map);
- cpu_set(cpuid, phys_cpu_present_map);
+ cpu_set(cpuid, cpu_possible_map);
}

int __cpuinit __cpu_up(unsigned int cpu)
--- linux-2.6.28.orig/arch/sparc/kernel/sparc_ksyms.c
+++ linux-2.6.28/arch/sparc/kernel/sparc_ksyms.c
@@ -113,10 +113,6 @@ EXPORT_PER_CPU_SYMBOL(__cpu_data);
#ifdef CONFIG_SMP
/* IRQ implementation. */
EXPORT_SYMBOL(synchronize_irq);
-
-/* CPU online map and active count. */
-EXPORT_SYMBOL(cpu_online_map);
-EXPORT_SYMBOL(phys_cpu_present_map);
#endif

EXPORT_SYMBOL(__udelay);
--- linux-2.6.28.orig/arch/sparc64/kernel/smp.c
+++ linux-2.6.28/arch/sparc64/kernel/smp.c
@@ -49,14 +49,10 @@

int sparc64_multi_core __read_mostly;

-cpumask_t cpu_possible_map __read_mostly = CPU_MASK_NONE;
-cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE;
DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
cpumask_t cpu_core_map[NR_CPUS] __read_mostly =
{ [0 ... NR_CPUS-1] = CPU_MASK_NONE };

-EXPORT_SYMBOL(cpu_possible_map);
-EXPORT_SYMBOL(cpu_online_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_SYMBOL(cpu_core_map);

--- linux-2.6.28.orig/arch/um/kernel/smp.c
+++ linux-2.6.28/arch/um/kernel/smp.c
@@ -25,13 +25,6 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_ga
#include "irq_user.h"
#include "os.h"

-/* CPU online map, set by smp_boot_cpus */
-cpumask_t cpu_online_map = CPU_MASK_NONE;
-cpumask_t cpu_possible_map = CPU_MASK_NONE;
-
-EXPORT_SYMBOL(cpu_online_map);
-EXPORT_SYMBOL(cpu_possible_map);
-
/* Per CPU bogomips and other parameters
* The only piece used here is the ipi pipe, which is set before SMP is
* started and never changed.
--- linux-2.6.28.orig/arch/x86/kernel/smpboot.c
+++ linux-2.6.28/arch/x86/kernel/smpboot.c
@@ -101,14 +101,8 @@ EXPORT_SYMBOL(smp_num_siblings);
/* Last level cache ID of each logical CPU */
DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;

-/* bitmap of online cpus */
-cpumask_t cpu_online_map __read_mostly;
-EXPORT_SYMBOL(cpu_online_map);
-
cpumask_t cpu_callin_map;
cpumask_t cpu_callout_map;
-cpumask_t cpu_possible_map;
-EXPORT_SYMBOL(cpu_possible_map);

/* representing HT siblings of each logical CPU */
DEFINE_PER_CPU(cpumask_t, cpu_sibling_map);
--- linux-2.6.28.orig/arch/x86/mach-voyager/voyager_smp.c
+++ linux-2.6.28/arch/x86/mach-voyager/voyager_smp.c
@@ -62,11 +62,6 @@ static int voyager_extended_cpus = 1;
/* Used for the invalidate map that's also checked in the spinlock */
static volatile unsigned long smp_invalidate_needed;

-/* Bitmask of currently online CPUs - used by setup.c for
- /proc/cpuinfo, visible externally but still physical */
-cpumask_t cpu_online_map = CPU_MASK_NONE;
-EXPORT_SYMBOL(cpu_online_map);
-
/* Bitmask of CPUs present in the system - exported by i386_syms.c, used
* by scheduler but indexed physically */
cpumask_t phys_cpu_present_map = CPU_MASK_NONE;
@@ -216,8 +211,6 @@ static cpumask_t smp_commenced_mask = CP
/* This is for the new dynamic CPU boot code */
cpumask_t cpu_callin_map = CPU_MASK_NONE;
cpumask_t cpu_callout_map = CPU_MASK_NONE;
-cpumask_t cpu_possible_map = CPU_MASK_NONE;
-EXPORT_SYMBOL(cpu_possible_map);

/* The per processor IRQ masks (these are usually kept in sync) */
static __u16 vic_irq_mask[NR_CPUS] __cacheline_aligned;
--- linux-2.6.28.orig/init/Kconfig
+++ linux-2.6.28/init/Kconfig
@@ -911,6 +911,15 @@ config KMOD

endif # MODULES

+config INIT_ALL_POSSIBLE
+ bool
+ help
+ Back when each arch used to define their own cpu_online_map and
+ cpu_possible_map, some of them chose to initialize cpu_possible_map
+ with all 1s, and others with all 0s. When they were centralised,
+ it was better to provide this option than to break all the archs
+ and have several arch maintainers persuing me down dark alleys.
+
config STOP_MACHINE
bool
default y
--- linux-2.6.28.orig/kernel/cpu.c
+++ linux-2.6.28/kernel/cpu.c
@@ -24,19 +24,20 @@
cpumask_t cpu_present_map __read_mostly;
EXPORT_SYMBOL(cpu_present_map);

-#ifndef CONFIG_SMP
-
/*
* Represents all cpu's that are currently online.
*/
-cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+cpumask_t cpu_online_map __read_mostly;
EXPORT_SYMBOL(cpu_online_map);

+#ifdef CONFIG_INIT_ALL_POSSIBLE
cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
+#else
+cpumask_t cpu_possible_map __read_mostly;
+#endif
EXPORT_SYMBOL(cpu_possible_map);

-#else /* CONFIG_SMP */
-
+#ifdef CONFIG_SMP
/* Serializes the updates to cpu_online_map, cpu_present_map */
static DEFINE_MUTEX(cpu_add_remove_lock);


--
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