/*
* x86 SMP booting functions
*
* (c) 1995 Alan Cox, Building #3 <alan@redhat.com>
* (c) 1998, 1999, 2000 Ingo Molnar <mingo@redhat.com>
* Copyright 2001 Andi Kleen, SuSE Labs.
*
* Much of the core SMP work is based on previous work by Thomas Radke, to
* whom a great many thanks are extended.
*
* Thanks to Intel for making available several different Pentium,
* Pentium Pro and Pentium-II/Xeon MP machines.
* Original development of Linux SMP code supported by Caldera.
*
* This code is released under the GNU General Public License version 2 or
* later.
*
* Fixes
* Felix Koop : NR_CPUS used properly
* Jose Renau : Handle single CPU case.
* Alan Cox : By repeated request 8) - Total BogoMIP report.
* Greg Wright : Fix for kernel stacks panic.
* Erich Boleyn : MP v1.4 and additional changes.
* Matthias Sattler : Changes for 2.1 kernel map.
* Michel Lespinasse : Changes for 2.1 kernel map.
* Michael Chastain : Change trampoline.S to gnu as.
* Alan Cox : Dumb bug: 'B' step PPro's are fine
* Ingo Molnar : Added APIC timers, based on code
* from Jose Renau
* Ingo Molnar : various cleanups and rewrites
* Tigran Aivazian : fixed "0.00 in /proc/uptime on SMP" bug.
* Maciej W. Rozycki : Bits for genuine 82489DX APICs
* Andi Kleen : Changed for SMP boot into long mode.
* Rusty Russell : Hacked into shape for new "hotplug" boot process.
*/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/smp_lock.h>
#include <linux/irq.h>
#include <linux/bootmem.h>
#include <linux/thread_info.h>
#include <linux/delay.h>
#include <linux/mc146818rtc.h>
#include <asm/mtrr.h>
#include <asm/pgalloc.h>
#include <asm/desc.h>
#include <asm/kdebug.h>
#include <asm/tlbflush.h>
#include <asm/proto.h>
/* Bitmask of currently online CPUs */
cpumask_t cpu_online_map;
static cpumask_t cpu_callin_map;
cpumask_t cpu_callout_map;
static cpumask_t smp_commenced_mask;
/* Per CPU bogomips and other parameters */
struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned;
/* Set when the idlers are all forked */
int smp_threads_ready;
/*
* Trampoline 80x86 program as an array.
*/
extern unsigned char trampoline_data [];
extern unsigned char trampoline_end [];
/*
* Currently trivial. Write the real->protected mode
* bootstrap into the page concerned. The caller
* has made sure it's suitably aligned.
*/
static unsigned long __init setup_trampoline(void)
{
void *tramp = __va(SMP_TRAMPOLINE_BASE);
extern volatile __u32 tramp_gdt_ptr;
tramp_gdt_ptr = __pa_symbol(&cpu_gdt_table);
memcpy(tramp, trampoline_data, trampoline_end - trampoline_data);
return virt_to_phys(tramp);
}
/*
* The bootstrap kernel entry code has set these up. Save them for
* a given CPU
*/
static void __init smp_store_cpu_info(int id)
{
struct cpuinfo_x86 *c = cpu_data + id;
*c = boot_cpu_data;
identify_cpu(c);
}
/*
* TSC synchronization.
*
* We first check whether all CPUs have their TSC's synchronized,
* then we print a warning if not, and always resync.
*/
static atomic_t tsc_start_flag = ATOMIC_INIT(0);
static atomic_t tsc_count_start = ATOMIC_INIT(0);
static atomic_t tsc_count_stop = ATOMIC_INIT(0);
static unsigned long long tsc_values[NR_CPUS];
#define NR_LOOPS 5
extern unsigned int fast_gettimeoffset_quotient;
static void __init synchronize_tsc_bp (void)
{
int i;
unsigned long long t0;
unsigned long long sum, avg;
long long delta;
long one_usec;
int buggy = 0;
printk(KERN_INFO "checking TSC synchronization across %u CPUs: ",num_booting_cpus());
one_usec = cpu_khz;
atomic_set(&tsc_start_flag, 1);
wmb();
/*
* We loop a few times to get a primed instruction cache,
* then the last pass is more or less synchronized and
* the BP and APs set their cycle counters to zero all at
* once. This reduces the chance of having random offsets
* between the processors, and guarantees that the maximum
* delay between the cycle counters is never bigger than
* the latency of information-passing (cachelines) between
* two CPUs.
*/
for (i = 0; i < NR_LOOPS; i++) {
/*
* all APs synchronize but they loop on '== num_cpus'
*/
while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) mb();
atomic_set(&tsc_count_stop, 0);
wmb();
/*
* this lets the APs save their current TSC:
*/
atomic_inc(&tsc_count_start);
sync_core();
rdtscll(tsc_values[smp_processor_id()]);
/*
* We clear the TSC in the last loop:
*/
if (i == NR_LOOPS-1)
write_tsc(0, 0);
/*
* Wait for all APs to leave the synchronization point:
*/
while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) mb();
atomic_set(&tsc_count_start, 0);
wmb();
atomic_inc(&tsc_count_stop);
}
sum = 0;
for (i = 0; i < NR_CPUS; i++) {
if (cpu_isset(i, cpu_callout_map)) {
t0 = tsc_values[i];
sum += t0;
}
}
avg = sum / num_booting_cpus();
sum = 0;
for (i = 0; i < NR_CPUS; i++) {
if (!cpu_isset(i, cpu_callout_map))
continue;
delta = tsc_values[i] - avg;
if (delta < 0)
delta = -delta;
/*
* We report bigger than 2 microseconds clock differences.
*/
if (delta > 2*one_usec) {
long realdelta;
if (!buggy) {
buggy = 1;
printk("\n");
}
realdelta = delta / one_usec;
if (tsc_values[i] < avg)
realdelta = -realdelta;
printk("BIOS BUG: CPU#%d improperly initialized, has %ld usecs TSC skew! FIXED.\n",
i, realdelta);
}
sum += delta;
}
if (!buggy)
printk("passed.\n");
}
static void __init synchronize_tsc_ap (void)
{
int i;
/*
* Not every cpu is online at the time
* this gets called, so we first wait for the BP to
* finish SMP initialization:
*/
while (!atomic_read(&tsc_start_flag)) mb();
for (i = 0; i < NR_LOOPS; i++) {
atomic_inc(&tsc_count_start);
while (atomic_read(&tsc_count_start) != num_booting_cpus()) mb();
sync_core();
rdtscll(tsc_values[smp_processor_id()]);
if (i == NR_LOOPS-1)
write_tsc(0, 0);
atomic_inc(&tsc_count_stop);
while (atomic_read(&tsc_count_stop) != num_booting_cpus()) mb();
}
}
#undef NR_LOOPS
static atomic_t init_deasserted;
void __init smp_callin(void)
{
int cpuid, phys_id;
unsigned long timeout;
/*
* If waken up by an INIT in an 82489DX configuration
* we may get here before an INIT-deassert IPI reaches
* our local APIC. We have to wait for the IPI or we'll
* lock up on an APIC access.
*/
while (!atomic_read(&init_deasserted));
/*
* (This works even if the APIC is not enabled.)
*/
phys_id = GET_APIC_ID(apic_read(APIC_ID));
cpuid = smp_processor_id();
if (cpu_test_and_set(cpuid, cpu_callin_map)) {
panic("smp_callin: phys CPU#%d, CPU#%d already present??\n",
phys_id, cpuid);
}
Dprintk("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
/*
* STARTUP IPIs are fragile beasts as they might sometimes
* trigger some glue motherboard logic. Complete APIC bus
* silence for 1 second, this overestimates the time the
* boot CPU is spending to send the up to 2 STARTUP IPIs
* by a factor of two. This should be enough.
*/
/*
* Waiting 2s total for startup (udelay is not yet working)
*/
timeout = jiffies + 2*HZ;
while (time_before(jiffies, timeout)) {
/*
* Has the boot CPU finished it's STARTUP sequence?
*/
if (cpu_isset(cpuid, cpu_callout_map))
break;
rep_nop();
}
if (!time_before(jiffies, timeout)) {
panic("smp_callin: CPU%d started up but did not get a callout!\n",
cpuid);
}
/*
* the boot CPU has finished the init stage and is spinning
* on callin_map until we finish. We are free to set up this
* CPU, first the APIC. (this is probably redundant on most
* boards)
*/
Dprintk("CALLIN, before setup_local_APIC().\n");
setup_local_APIC();
local_irq_enable();
/*
* Get our bogomips.
*/
calibrate_delay();
Dprintk("Stack at about %p\n",&cpuid);
disable_APIC_timer();
/*
* Save our processor parameters
*/
smp_store_cpu_info(cpuid);
local_irq_disable();
/*
* Allow the master to continue.
*/
cpu_set(cpuid, cpu_callin_map);
/*
* Synchronize the TSC with the BP
*/
if (cpu_has_tsc)
synchronize_tsc_ap();
}
int cpucount;
/*
* Activate a secondary processor.
*/
void __init start_secondary(void)
{
/*
* Dont put anything before smp_callin(), SMP
* booting is too fragile that we want to limit the
* things done here to the most necessary things.
*/
cpu_init();
smp_callin();
/* otherwise gcc will move up the smp_processor_id before the cpu_init */
barrier();
Dprintk("cpu %d: waiting for commence\n", smp_processor_id());
while (!cpu_isset(smp_processor_id(), smp_commenced_mask))
rep_nop();
Dprintk("cpu %d: setting up apic clock\n", smp_processor_id());
setup_secondary_APIC_clock();
Dprintk("cpu %d: enabling apic timer\n", smp_processor_id());
if (nmi_watchdog == NMI_IO_APIC) {
disable_8259A_irq(0);
enable_NMI_through_LVT0(NULL);
enable_8259A_irq(0);
}
enable_APIC_timer();
/*
* low-memory mappings have been cleared, flush them from
* the local TLBs too.
*/
local_flush_tlb();
Dprintk("cpu %d eSetting cpu_online_map\n", smp_processor_id());
cpu_set(smp_processor_id(), cpu_online_map);
wmb();
cpu_idle();
}
extern volatile unsigned long init_rsp;
extern void (*initial_code)(void);
static struct task_struct * __init fork_by_hand(void)
{
struct pt_regs regs;
/*
* don't care about the eip and regs settings since
* we'll never reschedule the forked task.
*/
return copy_process(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0, NULL, NULL);
}
#if APIC_DEBUG
static inline void inquire_remote_apic(int apicid)
{
unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
char *names[] = { "ID", "VERSION", "SPIV" };
int timeout, status;
printk(KERN_INFO "Inquiring remote APIC #%d...\n", apicid);
for (i = 0; i < sizeof(regs) / sizeof(*regs); i++) {
printk("... APIC #%d %s: ", apicid, names[i]);
/*
* Wait for idle.
*/
apic_wait_icr_idle();
apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(apicid));
apic_write_around(APIC_ICR, APIC_DM_REMRD | regs[i]);
timeout = 0;
do {
udelay(100);
status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
switch (status) {
case APIC_ICR_RR_VALID:
status = apic_read(APIC_RRR);
printk("%08x\n", status);
break;
default:
printk("failed\n");
}
}
}
#endif
static int __init wakeup_secondary_via_INIT(int phys_apicid, unsigned int start_rip)
{
unsigned long send_status = 0, accept_status = 0;
int maxlvt, timeout, num_starts, j;
Dprintk("Asserting INIT.\n");
/*
* Turn INIT on target chip
*/
apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
/*
* Send IPI
*/
apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_INT_ASSERT
| APIC_DM_INIT);
Dprintk("Waiting for send to finish...\n");
timeout = 0;
do {
Dprintk("+");
udelay(100);
send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
} while (send_status && (timeout++ < 1000));
mdelay(10);
Dprintk("Deasserting INIT.\n");
/* Target chip */
apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
/* Send IPI */
apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_DM_INIT);
Dprintk("Waiting for send to finish...\n");
timeout = 0;
do {
Dprintk("+");
udelay(100);
send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
} while (send_status && (timeout++ < 1000));
atomic_set(&init_deasserted, 1);
/*
* Should we send STARTUP IPIs ?
*
* Determine this based on the APIC version.
* If we don't have an integrated APIC, don't send the STARTUP IPIs.
*/
if (APIC_INTEGRATED(apic_version[phys_apicid]))
num_starts = 2;
else
num_starts = 0;
/*
* Run STARTUP IPI loop.
*/
Dprintk("#startup loops: %d.\n", num_starts);
maxlvt = get_maxlvt();
for (j = 1; j <= num_starts; j++) {
Dprintk("Sending STARTUP #%d.\n",j);
apic_read_around(APIC_SPIV);
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
Dprintk("After apic_write.\n");
/*
* STARTUP IPI
*/
/* Target chip */
apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
/* Boot on the stack */
/* Kick the second */
apic_write_around(APIC_ICR, APIC_DM_STARTUP
| (start_rip >> 12));
/*
* Give the other CPU some time to accept the IPI.
*/
udelay(300);
Dprintk("Startup point 1.\n");
Dprintk("Waiting for send to finish...\n");
timeout = 0;
do {
Dprintk("+");
udelay(100);
send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
} while (send_status && (timeout++ < 1000));
/*
* Give the other CPU some time to accept the IPI.
*/
udelay(200);
/*
* Due to the Pentium erratum 3AP.
*/
if (maxlvt > 3) {
apic_read_around(APIC_SPIV);
apic_write(APIC_ESR, 0);
}
accept_status = (apic_read(APIC_ESR) & 0xEF);
if (send_status || accept_status)
break;
}
Dprintk("After Startup.\n");
if (send_status)
printk(KERN_ERR "APIC never delivered???\n");
if (accept_status)
printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
return (send_status | accept_status);
}
static void __init do_boot_cpu (int apicid)
{
struct task_struct *idle;
unsigned long boot_error;
int timeout, cpu;
unsigned long start_rip;
cpu = ++cpucount;
/*
* We can't use kernel_thread since we must avoid to
* reschedule the child.
*/
idle = fork_by_hand();
if (IS_ERR(idle))
panic("failed fork for CPU %d", cpu);
wake_up_forked_process(idle);
/*
* We remove it from the pidhash and the runqueue
* once we got the process:
*/
init_idle(idle,cpu);
unhash_process(idle);
cpu_pda[cpu].pcurrent = idle;
start_rip = setup_trampoline();
init_rsp = idle->thread.rsp;
init_tss[cpu].rsp0 = init_rsp;
initial_code = start_secondary;
clear_ti_thread_flag(idle->thread_info, TIF_FORK);
printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid,
start_rip, init_rsp);
/*
* This grunge runs the startup process for
* the targeted processor.
*/
atomic_set(&init_deasserted, 0);
Dprintk("Setting warm reset code and vector.\n");
CMOS_WRITE(0xa, 0xf);
local_flush_tlb();
Dprintk("1.\n");
*((volatile unsigned short *) phys_to_virt(0x469)) = start_rip >> 4;
Dprintk("2.\n");
*((volatile unsigned short *) phys_to_virt(0x467)) = start_rip & 0xf;
Dprintk("3.\n");
/*
* Be paranoid about clearing APIC errors.
*/
if (APIC_INTEGRATED(apic_version[apicid])) {
apic_read_around(APIC_SPIV);
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
}
/*
* Status is now clean
*/
boot_error = 0;
/*
* Starting actual IPI sequence...
*/
boot_error = wakeup_secondary_via_INIT(apicid, start_rip);
if (!boot_error) {
/*
* allow APs to start initializing.
*/
Dprintk("Before Callout %d.\n", cpu);
cpu_set(cpu, cpu_callout_map);
Dprintk("After Callout %d.\n", cpu);
/*
* Wait 5s total for a response
*/
for (timeout = 0; timeout < 50000; timeout++) {
if (cpu_isset(cpu, cpu_callin_map))
break; /* It has booted */
udelay(100);
}
if (cpu_isset(cpu, cpu_callin_map)) {
/* number CPUs logically, starting from 1 (BSP is 0) */
Dprintk("OK.\n");
printk(KERN_INFO "CPU%d: ", cpu);
print_cpu_info(&cpu_data[cpu]);
Dprintk("CPU has booted.\n");
} else {
boot_error = 1;
if (*((volatile unsigned char *)phys_to_virt(8192))
== 0xA5)
/* trampoline started but...? */
printk("Stuck ??\n");
else
/* trampoline code not run */
printk("Not responding.\n");
#if APIC_DEBUG
inquire_remote_apic(apicid);
#endif
}
}
if (boot_error) {
cpu_clear(cpu, cpu_callout_map); /* was set here (do_boot_cpu()) */
clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */
cpucount--;
}
/* mark "stuck" area as not stuck */
*((volatile unsigned *)phys_to_virt(8192)) = 0;
}
cycles_t cacheflush_time;
unsigned long cache_decay_ticks;
static void smp_tune_scheduling (void)
{
int cachesize; /* kB */
unsigned long bandwidth = 1000; /* MB/s */
/*
* Rough estimation for SMP scheduling, this is the number of
* cycles it takes for a fully memory-limited process to flush
* the SMP-local cache.
*
* (For a P5 this pretty much means we will choose another idle
* CPU almost always at wakeup time (this is due to the small
* L1 cache), on PIIs it's around 50-100 usecs, depending on
* the cache size)
*/
if (!cpu_khz) {
/*
* this basically disables processor-affinity
* scheduling on SMP without a TSC.
*/
cacheflush_time = 0;
return;
} else {
cachesize = boot_cpu_data.x86_cache_size;
if (cachesize == -1) {
cachesize = 16; /* Pentiums, 2x8kB cache */
bandwidth = 100;
}
cacheflush_time = (cpu_khz>>10) * (cachesize<<10) / bandwidth;
}
cache_decay_ticks = (long)cacheflush_time/cpu_khz * HZ / 1000;
printk(KERN_INFO "per-CPU timeslice cutoff: %ld.%02ld usecs.\n",
(long)cacheflush_time/(cpu_khz/1000),
((long)cacheflush_time*100/(cpu_khz/1000)) % 100);
printk(KERN_INFO "task migration cache decay timeout: %ld msecs.\n",
(cache_decay_ticks + 1) * 1000 / HZ);
}
/*
* Cycle through the processors sending APIC IPIs to boot each.
*/
static void __init smp_boot_cpus(unsigned int max_cpus)
{
unsigned apicid, cpu;
/*
* Setup boot CPU information
*/
smp_store_cpu_info(0); /* Final full version of the data */
printk(KERN_INFO "CPU%d: ", 0);
print_cpu_info(&cpu_data[0]);
current_thread_info()->cpu = 0;
smp_tune_scheduling();
if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
printk("weird, boot CPU (#%d) not listed by the BIOS.\n",
hard_smp_processor_id());
physid_set(hard_smp_processor_id(), phys_cpu_present_map);
}
/*
* If we couldn't find an SMP configuration at boot time,
* get out of here now!
*/
if (!smp_found_config) {
printk(KERN_NOTICE "SMP motherboard not detected.\n");
io_apic_irqs = 0;
cpu_online_map = cpumask_of_cpu(0);
phys_cpu_present_map = physid_mask_of_physid(0);
if (APIC_init_uniprocessor())
printk(KERN_NOTICE "Local APIC not detected."
" Using dummy APIC emulation.\n");
goto smp_done;
}
/*
* Should not be necessary because the MP table should list the boot
* CPU too, but we do it for the sake of robustness anyway.
*/
if (!physid_isset(boot_cpu_id, phys_cpu_present_map)) {
printk(KERN_NOTICE "weird, boot CPU (#%d) not listed by the BIOS.\n",
boot_cpu_id);
physid_set(hard_smp_processor_id(), phys_cpu_present_map);
}
/*
* If we couldn't find a local APIC, then get out of here now!
*/
if (APIC_INTEGRATED(apic_version[boot_cpu_id]) && !cpu_has_apic) {
printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
boot_cpu_id);
printk(KERN_ERR "... forcing use of dummy APIC emulation. (tell your hw vendor)\n");
io_apic_irqs = 0;
cpu_online_map = cpumask_of_cpu(0);
phys_cpu_present_map = physid_mask_of_physid(0);
disable_apic = 1;
goto smp_done;
}
verify_local_APIC();
/*
* If SMP should be disabled, then really disable it!
*/
if (!max_cpus) {
smp_found_config = 0;
printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
io_apic_irqs = 0;
cpu_online_map = cpumask_of_cpu(0);
phys_cpu_present_map = physid_mask_of_physid(0);
disable_apic = 1;
goto smp_done;
}
connect_bsp_APIC();
setup_local_APIC();
if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id)
BUG();
/*
* Now scan the CPU present map and fire up the other CPUs.
*/
Dprintk("CPU present map: %lx\n", physids_coerce(phys_cpu_present_map));
for (apicid = 0; apicid < NR_CPUS; apicid++) {
/*
* Don't even attempt to start the boot CPU!
*/
if (apicid == boot_cpu_id)
continue;
if (!cpu_isset(apicid, phys_cpu_present_map))
continue;
if ((max_cpus >= 0) && (max_cpus <= cpucount+1))
continue;
do_boot_cpu(apicid);
}
/*
* Cleanup possible dangling ends...
*/
{
/*
* Install writable page 0 entry to set BIOS data area.
*/
local_flush_tlb();
/*
* Paranoid: Set warm reset code and vector here back
* to default values.
*/
CMOS_WRITE(0, 0xf);
*((volatile int *) phys_to_virt(0x467)) = 0;
}
/*
* Allow the user to impress friends.
*/
Dprintk("Before bogomips.\n");
if (!cpucount) {
printk(KERN_INFO "Only one processor found.\n");
} else {
unsigned long bogosum = 0;
for (cpu = 0; cpu < NR_CPUS; cpu++)
if (cpu_isset(cpu, cpu_callout_map))
bogosum += cpu_data[cpu].loops_per_jiffy;
printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
cpucount+1,
bogosum/(500000/HZ),
(bogosum/(5000/HZ))%100);
Dprintk("Before bogocount - setting activated=1.\n");
}
Dprintk("Boot done.\n");
/*
* Here we can be sure that there is an IO-APIC in the system. Let's
* go and set it up:
*/
if (!skip_ioapic_setup && nr_ioapics)
setup_IO_APIC();
else
nr_ioapics = 0;
setup_boot_APIC_clock();
/*
* Synchronize the TSC with the AP
*/
if (cpu_has_tsc && cpucount)
synchronize_tsc_bp();
smp_done:
time_init_smp();
}
/* These are wrappers to interface to the new boot process. Someone
who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
smp_boot_cpus(max_cpus);
}
void __devinit smp_prepare_boot_cpu(void)
{
cpu_set(smp_processor_id(), cpu_online_map);
cpu_set(smp_processor_id(), cpu_callout_map);
}
int __devinit __cpu_up(unsigned int cpu)
{
/* This only works at boot for x86. See "rewrite" above. */
if (cpu_isset(cpu, smp_commenced_mask)) {
local_irq_enable();
return -ENOSYS;
}
/* In case one didn't come up */
if (!cpu_isset(cpu, cpu_callin_map)) {
local_irq_enable();
return -EIO;
}
local_irq_enable();
/* Unleash the CPU! */
Dprintk("waiting for cpu %d\n", cpu);
cpu_set(cpu, smp_commenced_mask);
while (!cpu_isset(cpu, cpu_online_map))
mb();
return 0;
}
void __init smp_cpus_done(unsigned int max_cpus)
{
zap_low_mappings();
}
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