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gem5 / arm / linux / 1cce91dfc8f7990ca3aea896bfb148f240b12860 / . / arch / x86 / kernel / smpboot.c
blob: 0854ff1692745adf4831e2deea0cb203977847d9 [file] [log] [blame]
/*
* x86 SMP booting functions
*
* (c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
* (c) 1998, 1999, 2000, 2009 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 BogoMIPS 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.
* Martin J. Bligh : Added support for multi-quad systems
* Dave Jones : Report invalid combinations of Athlon CPUs.
* Rusty Russell : Hacked into shape for new "hotplug" boot process.
* Andi Kleen : Converted to new state machine.
* Ashok Raj : CPU hotplug support
* Glauber Costa : i386 and x86_64 integration
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/topology.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task_stack.h>
#include <linux/percpu.h>
#include <linux/bootmem.h>
#include <linux/err.h>
#include <linux/nmi.h>
#include <linux/tboot.h>
#include <linux/stackprotector.h>
#include <linux/gfp.h>
#include <linux/cpuidle.h>
#include <asm/acpi.h>
#include <asm/desc.h>
#include <asm/nmi.h>
#include <asm/irq.h>
#include <asm/realmode.h>
#include <asm/cpu.h>
#include <asm/numa.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mtrr.h>
#include <asm/mwait.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/fpu/internal.h>
#include <asm/setup.h>
#include <asm/uv/uv.h>
#include <linux/mc146818rtc.h>
#include <asm/i8259.h>
#include <asm/realmode.h>
#include <asm/misc.h>
/* Number of siblings per CPU package */
int smp_num_siblings = 1;
EXPORT_SYMBOL(smp_num_siblings);
/* Last level cache ID of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID;
/* representing HT siblings of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
/* representing HT and core siblings of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
/* Per CPU bogomips and other parameters */
DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
EXPORT_PER_CPU_SYMBOL(cpu_info);
/* Logical package management. We might want to allocate that dynamically */
static int *physical_to_logical_pkg __read_mostly;
static unsigned long *physical_package_map __read_mostly;;
static unsigned int max_physical_pkg_id __read_mostly;
unsigned int __max_logical_packages __read_mostly;
EXPORT_SYMBOL(__max_logical_packages);
static unsigned int logical_packages __read_mostly;
/* Maximum number of SMT threads on any online core */
int __max_smt_threads __read_mostly;
/* Flag to indicate if a complete sched domain rebuild is required */
bool x86_topology_update;
int arch_update_cpu_topology(void)
{
int retval = x86_topology_update;
x86_topology_update = false;
return retval;
}
static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
{
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
CMOS_WRITE(0xa, 0xf);
spin_unlock_irqrestore(&rtc_lock, flags);
local_flush_tlb();
pr_debug("1.\n");
*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
start_eip >> 4;
pr_debug("2.\n");
*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
start_eip & 0xf;
pr_debug("3.\n");
}
static inline void smpboot_restore_warm_reset_vector(void)
{
unsigned long flags;
/*
* 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.
*/
spin_lock_irqsave(&rtc_lock, flags);
CMOS_WRITE(0, 0xf);
spin_unlock_irqrestore(&rtc_lock, flags);
*((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0;
}
/*
* Report back to the Boot Processor during boot time or to the caller processor
* during CPU online.
*/
static void smp_callin(void)
{
int cpuid, phys_id;
/*
* If waken up by an INIT in an 82489DX configuration
* cpu_callout_mask guarantees we don't get here before
* an INIT_deassert IPI reaches our local APIC, so it is
* now safe to touch our local APIC.
*/
cpuid = smp_processor_id();
/*
* (This works even if the APIC is not enabled.)
*/
phys_id = read_apic_id();
/*
* 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)
*/
apic_ap_setup();
/*
* Save our processor parameters. Note: this information
* is needed for clock calibration.
*/
smp_store_cpu_info(cpuid);
/*
* Get our bogomips.
* Update loops_per_jiffy in cpu_data. Previous call to
* smp_store_cpu_info() stored a value that is close but not as
* accurate as the value just calculated.
*/
calibrate_delay();
cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
pr_debug("Stack at about %p\n", &cpuid);
/*
* This must be done before setting cpu_online_mask
* or calling notify_cpu_starting.
*/
set_cpu_sibling_map(raw_smp_processor_id());
wmb();
notify_cpu_starting(cpuid);
/*
* Allow the master to continue.
*/
cpumask_set_cpu(cpuid, cpu_callin_mask);
}
static int cpu0_logical_apicid;
static int enable_start_cpu0;
/*
* Activate a secondary processor.
*/
static void notrace start_secondary(void *unused)
{
/*
* Don't put *anything* except direct CPU state initialization
* before cpu_init(), SMP booting is too fragile that we want to
* limit the things done here to the most necessary things.
*/
if (boot_cpu_has(X86_FEATURE_PCID))
__write_cr4(__read_cr4() | X86_CR4_PCIDE);
cpu_init();
x86_cpuinit.early_percpu_clock_init();
preempt_disable();
smp_callin();
enable_start_cpu0 = 0;
#ifdef CONFIG_X86_32
/* switch away from the initial page table */
load_cr3(swapper_pg_dir);
__flush_tlb_all();
#endif
/* otherwise gcc will move up smp_processor_id before the cpu_init */
barrier();
/*
* Check TSC synchronization with the BP:
*/
check_tsc_sync_target();
/*
* Lock vector_lock and initialize the vectors on this cpu
* before setting the cpu online. We must set it online with
* vector_lock held to prevent a concurrent setup/teardown
* from seeing a half valid vector space.
*/
lock_vector_lock();
setup_vector_irq(smp_processor_id());
set_cpu_online(smp_processor_id(), true);
unlock_vector_lock();
cpu_set_state_online(smp_processor_id());
x86_platform.nmi_init();
/* enable local interrupts */
local_irq_enable();
/* to prevent fake stack check failure in clock setup */
boot_init_stack_canary();
x86_cpuinit.setup_percpu_clockev();
wmb();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
/**
* topology_update_package_map - Update the physical to logical package map
* @pkg: The physical package id as retrieved via CPUID
* @cpu: The cpu for which this is updated
*/
int topology_update_package_map(unsigned int pkg, unsigned int cpu)
{
unsigned int new;
/* Called from early boot ? */
if (!physical_package_map)
return 0;
if (pkg >= max_physical_pkg_id)
return -EINVAL;
/* Set the logical package id */
if (test_and_set_bit(pkg, physical_package_map))
goto found;
if (logical_packages >= __max_logical_packages) {
pr_warn("Package %u of CPU %u exceeds BIOS package data %u.\n",
logical_packages, cpu, __max_logical_packages);
return -ENOSPC;
}
new = logical_packages++;
if (new != pkg) {
pr_info("CPU %u Converting physical %u to logical package %u\n",
cpu, pkg, new);
}
physical_to_logical_pkg[pkg] = new;
found:
cpu_data(cpu).logical_proc_id = physical_to_logical_pkg[pkg];
return 0;
}
/**
* topology_phys_to_logical_pkg - Map a physical package id to a logical
*
* Returns logical package id or -1 if not found
*/
int topology_phys_to_logical_pkg(unsigned int phys_pkg)
{
if (phys_pkg >= max_physical_pkg_id)
return -1;
return physical_to_logical_pkg[phys_pkg];
}
EXPORT_SYMBOL(topology_phys_to_logical_pkg);
static void __init smp_init_package_map(struct cpuinfo_x86 *c, unsigned int cpu)
{
unsigned int ncpus;
size_t size;
/*
* Today neither Intel nor AMD support heterogenous systems. That
* might change in the future....
*
* While ideally we'd want '* smp_num_siblings' in the below @ncpus
* computation, this won't actually work since some Intel BIOSes
* report inconsistent HT data when they disable HT.
*
* In particular, they reduce the APIC-IDs to only include the cores,
* but leave the CPUID topology to say there are (2) siblings.
* This means we don't know how many threads there will be until
* after the APIC enumeration.
*
* By not including this we'll sometimes over-estimate the number of
* logical packages by the amount of !present siblings, but this is
* still better than MAX_LOCAL_APIC.
*
* We use total_cpus not nr_cpu_ids because nr_cpu_ids can be limited
* on the command line leading to a similar issue as the HT disable
* problem because the hyperthreads are usually enumerated after the
* primary cores.
*/
ncpus = boot_cpu_data.x86_max_cores;
if (!ncpus) {
pr_warn("x86_max_cores == zero !?!?");
ncpus = 1;
}
__max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
logical_packages = 0;
/*
* Possibly larger than what we need as the number of apic ids per
* package can be smaller than the actual used apic ids.
*/
max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
size = max_physical_pkg_id * sizeof(unsigned int);
physical_to_logical_pkg = kmalloc(size, GFP_KERNEL);
memset(physical_to_logical_pkg, 0xff, size);
size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
physical_package_map = kzalloc(size, GFP_KERNEL);
pr_info("Max logical packages: %u\n", __max_logical_packages);
topology_update_package_map(c->phys_proc_id, cpu);
}
void __init smp_store_boot_cpu_info(void)
{
int id = 0; /* CPU 0 */
struct cpuinfo_x86 *c = &cpu_data(id);
*c = boot_cpu_data;
c->cpu_index = id;
smp_init_package_map(c, id);
}
/*
* The bootstrap kernel entry code has set these up. Save them for
* a given CPU
*/
void smp_store_cpu_info(int id)
{
struct cpuinfo_x86 *c = &cpu_data(id);
*c = boot_cpu_data;
c->cpu_index = id;
/*
* During boot time, CPU0 has this setup already. Save the info when
* bringing up AP or offlined CPU0.
*/
identify_secondary_cpu(c);
}
static bool
topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
{
int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
return (cpu_to_node(cpu1) == cpu_to_node(cpu2));
}
static bool
topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
{
int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
return !WARN_ONCE(!topology_same_node(c, o),
"sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
"[node: %d != %d]. Ignoring dependency.\n",
cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
}
#define link_mask(mfunc, c1, c2) \
do { \
cpumask_set_cpu((c1), mfunc(c2)); \
cpumask_set_cpu((c2), mfunc(c1)); \
} while (0)
static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
{
if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
if (c->phys_proc_id == o->phys_proc_id &&
per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
if (c->cpu_core_id == o->cpu_core_id)
return topology_sane(c, o, "smt");
if ((c->cu_id != 0xff) &&
(o->cu_id != 0xff) &&
(c->cu_id == o->cu_id))
return topology_sane(c, o, "smt");
}
} else if (c->phys_proc_id == o->phys_proc_id &&
c->cpu_core_id == o->cpu_core_id) {
return topology_sane(c, o, "smt");
}
return false;
}
static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
{
int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID &&
per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2))
return topology_sane(c, o, "llc");
return false;
}
/*
* Unlike the other levels, we do not enforce keeping a
* multicore group inside a NUMA node. If this happens, we will
* discard the MC level of the topology later.
*/
static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
{
if (c->phys_proc_id == o->phys_proc_id)
return true;
return false;
}
#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
static inline int x86_sched_itmt_flags(void)
{
return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
}
#ifdef CONFIG_SCHED_MC
static int x86_core_flags(void)
{
return cpu_core_flags() | x86_sched_itmt_flags();
}
#endif
#ifdef CONFIG_SCHED_SMT
static int x86_smt_flags(void)
{
return cpu_smt_flags() | x86_sched_itmt_flags();
}
#endif
#endif
static struct sched_domain_topology_level x86_numa_in_package_topology[] = {
#ifdef CONFIG_SCHED_SMT
{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
#endif
#ifdef CONFIG_SCHED_MC
{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
#endif
{ NULL, },
};
static struct sched_domain_topology_level x86_topology[] = {
#ifdef CONFIG_SCHED_SMT
{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
#endif
#ifdef CONFIG_SCHED_MC
{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
#endif
{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
{ NULL, },
};
/*
* Set if a package/die has multiple NUMA nodes inside.
* AMD Magny-Cours and Intel Cluster-on-Die have this.
*/
static bool x86_has_numa_in_package;
void set_cpu_sibling_map(int cpu)
{
bool has_smt = smp_num_siblings > 1;
bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
struct cpuinfo_x86 *c = &cpu_data(cpu);
struct cpuinfo_x86 *o;
int i, threads;
cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
if (!has_mp) {
cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
c->booted_cores = 1;
return;
}
for_each_cpu(i, cpu_sibling_setup_mask) {
o = &cpu_data(i);
if ((i == cpu) || (has_smt && match_smt(c, o)))
link_mask(topology_sibling_cpumask, cpu, i);
if ((i == cpu) || (has_mp && match_llc(c, o)))
link_mask(cpu_llc_shared_mask, cpu, i);
}
/*
* This needs a separate iteration over the cpus because we rely on all
* topology_sibling_cpumask links to be set-up.
*/
for_each_cpu(i, cpu_sibling_setup_mask) {
o = &cpu_data(i);
if ((i == cpu) || (has_mp && match_die(c, o))) {
link_mask(topology_core_cpumask, cpu, i);
/*
* Does this new cpu bringup a new core?
*/
if (cpumask_weight(
topology_sibling_cpumask(cpu)) == 1) {
/*
* for each core in package, increment
* the booted_cores for this new cpu
*/
if (cpumask_first(
topology_sibling_cpumask(i)) == i)
c->booted_cores++;
/*
* increment the core count for all
* the other cpus in this package
*/
if (i != cpu)
cpu_data(i).booted_cores++;
} else if (i != cpu && !c->booted_cores)
c->booted_cores = cpu_data(i).booted_cores;
}
if (match_die(c, o) && !topology_same_node(c, o))
x86_has_numa_in_package = true;
}
threads = cpumask_weight(topology_sibling_cpumask(cpu));
if (threads > __max_smt_threads)
__max_smt_threads = threads;
}
/* maps the cpu to the sched domain representing multi-core */
const struct cpumask *cpu_coregroup_mask(int cpu)
{
return cpu_llc_shared_mask(cpu);
}
static void impress_friends(void)
{
int cpu;
unsigned long bogosum = 0;
/*
* Allow the user to impress friends.
*/
pr_debug("Before bogomips\n");
for_each_possible_cpu(cpu)
if (cpumask_test_cpu(cpu, cpu_callout_mask))
bogosum += cpu_data(cpu).loops_per_jiffy;
pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
num_online_cpus(),
bogosum/(500000/HZ),
(bogosum/(5000/HZ))%100);
pr_debug("Before bogocount - setting activated=1\n");
}
void __inquire_remote_apic(int apicid)
{
unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
const char * const names[] = { "ID", "VERSION", "SPIV" };
int timeout;
u32 status;
pr_info("Inquiring remote APIC 0x%x...\n", apicid);
for (i = 0; i < ARRAY_SIZE(regs); i++) {
pr_info("... APIC 0x%x %s: ", apicid, names[i]);
/*
* Wait for idle.
*/
status = safe_apic_wait_icr_idle();
if (status)
pr_cont("a previous APIC delivery may have failed\n");
apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
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);
pr_cont("%08x\n", status);
break;
default:
pr_cont("failed\n");
}
}
}
/*
* The Multiprocessor Specification 1.4 (1997) example code suggests
* that there should be a 10ms delay between the BSP asserting INIT
* and de-asserting INIT, when starting a remote processor.
* But that slows boot and resume on modern processors, which include
* many cores and don't require that delay.
*
* Cmdline "init_cpu_udelay=" is available to over-ride this delay.
* Modern processor families are quirked to remove the delay entirely.
*/
#define UDELAY_10MS_DEFAULT 10000
static unsigned int init_udelay = UINT_MAX;
static int __init cpu_init_udelay(char *str)
{
get_option(&str, &init_udelay);
return 0;
}
early_param("cpu_init_udelay", cpu_init_udelay);
static void __init smp_quirk_init_udelay(void)
{
/* if cmdline changed it from default, leave it alone */
if (init_udelay != UINT_MAX)
return;
/* if modern processor, use no delay */
if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
init_udelay = 0;
return;
}
/* else, use legacy delay */
init_udelay = UDELAY_10MS_DEFAULT;
}
/*
* Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
* INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
* won't ... remember to clear down the APIC, etc later.
*/
int
wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
{
unsigned long send_status, accept_status = 0;
int maxlvt;
/* Target chip */
/* Boot on the stack */
/* Kick the second */
apic_icr_write(APIC_DM_NMI | apic->dest_logical, apicid);
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
/*
* Give the other CPU some time to accept the IPI.
*/
udelay(200);
if (APIC_INTEGRATED(boot_cpu_apic_version)) {
maxlvt = lapic_get_maxlvt();
if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
accept_status = (apic_read(APIC_ESR) & 0xEF);
}
pr_debug("NMI sent\n");
if (send_status)
pr_err("APIC never delivered???\n");
if (accept_status)
pr_err("APIC delivery error (%lx)\n", accept_status);
return (send_status | accept_status);
}
static int
wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
{
unsigned long send_status = 0, accept_status = 0;
int maxlvt, num_starts, j;
maxlvt = lapic_get_maxlvt();
/*
* Be paranoid about clearing APIC errors.
*/
if (APIC_INTEGRATED(boot_cpu_apic_version)) {
if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
}
pr_debug("Asserting INIT\n");
/*
* Turn INIT on target chip
*/
/*
* Send IPI
*/
apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
phys_apicid);
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
udelay(init_udelay);
pr_debug("Deasserting INIT\n");
/* Target chip */
/* Send IPI */
apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
mb();
/*
* 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(boot_cpu_apic_version))
num_starts = 2;
else
num_starts = 0;
/*
* Run STARTUP IPI loop.
*/
pr_debug("#startup loops: %d\n", num_starts);
for (j = 1; j <= num_starts; j++) {
pr_debug("Sending STARTUP #%d\n", j);
if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
pr_debug("After apic_write\n");
/*
* STARTUP IPI
*/
/* Target chip */
/* Boot on the stack */
/* Kick the second */
apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
phys_apicid);
/*
* Give the other CPU some time to accept the IPI.
*/
if (init_udelay == 0)
udelay(10);
else
udelay(300);
pr_debug("Startup point 1\n");
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
/*
* Give the other CPU some time to accept the IPI.
*/
if (init_udelay == 0)
udelay(10);
else
udelay(200);
if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
accept_status = (apic_read(APIC_ESR) & 0xEF);
if (send_status || accept_status)
break;
}
pr_debug("After Startup\n");
if (send_status)
pr_err("APIC never delivered???\n");
if (accept_status)
pr_err("APIC delivery error (%lx)\n", accept_status);
return (send_status | accept_status);
}
/* reduce the number of lines printed when booting a large cpu count system */
static void announce_cpu(int cpu, int apicid)
{
static int current_node = -1;
int node = early_cpu_to_node(cpu);
static int width, node_width;
if (!width)
width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
if (!node_width)
node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */
if (cpu == 1)
printk(KERN_INFO "x86: Booting SMP configuration:\n");
if (system_state < SYSTEM_RUNNING) {
if (node != current_node) {
if (current_node > (-1))
pr_cont("\n");
current_node = node;
printk(KERN_INFO ".... node %*s#%d, CPUs: ",
node_width - num_digits(node), " ", node);
}
/* Add padding for the BSP */
if (cpu == 1)
pr_cont("%*s", width + 1, " ");
pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
} else
pr_info("Booting Node %d Processor %d APIC 0x%x\n",
node, cpu, apicid);
}
static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
{
int cpu;
cpu = smp_processor_id();
if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0)
return NMI_HANDLED;
return NMI_DONE;
}
/*
* Wake up AP by INIT, INIT, STARTUP sequence.
*
* Instead of waiting for STARTUP after INITs, BSP will execute the BIOS
* boot-strap code which is not a desired behavior for waking up BSP. To
* void the boot-strap code, wake up CPU0 by NMI instead.
*
* This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined
* (i.e. physically hot removed and then hot added), NMI won't wake it up.
* We'll change this code in the future to wake up hard offlined CPU0 if
* real platform and request are available.
*/
static int
wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
int *cpu0_nmi_registered)
{
int id;
int boot_error;
preempt_disable();
/*
* Wake up AP by INIT, INIT, STARTUP sequence.
*/
if (cpu) {
boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
goto out;
}
/*
* Wake up BSP by nmi.
*
* Register a NMI handler to help wake up CPU0.
*/
boot_error = register_nmi_handler(NMI_LOCAL,
wakeup_cpu0_nmi, 0, "wake_cpu0");
if (!boot_error) {
enable_start_cpu0 = 1;
*cpu0_nmi_registered = 1;
if (apic->dest_logical == APIC_DEST_LOGICAL)
id = cpu0_logical_apicid;
else
id = apicid;
boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip);
}
out:
preempt_enable();
return boot_error;
}
void common_cpu_up(unsigned int cpu, struct task_struct *idle)
{
/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
per_cpu(current_task, cpu) = idle;
#ifdef CONFIG_X86_32
/* Stack for startup_32 can be just as for start_secondary onwards */
irq_ctx_init(cpu);
per_cpu(cpu_current_top_of_stack, cpu) =
(unsigned long)task_stack_page(idle) + THREAD_SIZE;
#else
initial_gs = per_cpu_offset(cpu);
#endif
}
/*
* NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
* (ie clustered apic addressing mode), this is a LOGICAL apic ID.
* Returns zero if CPU booted OK, else error code from
* ->wakeup_secondary_cpu.
*/
static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
int *cpu0_nmi_registered)
{
volatile u32 *trampoline_status =
(volatile u32 *) __va(real_mode_header->trampoline_status);
/* start_ip had better be page-aligned! */
unsigned long start_ip = real_mode_header->trampoline_start;
unsigned long boot_error = 0;
unsigned long timeout;
idle->thread.sp = (unsigned long)task_pt_regs(idle);
early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu);
initial_code = (unsigned long)start_secondary;
initial_stack = idle->thread.sp;
/*
* Enable the espfix hack for this CPU
*/
#ifdef CONFIG_X86_ESPFIX64
init_espfix_ap(cpu);
#endif
/* So we see what's up */
announce_cpu(cpu, apicid);
/*
* This grunge runs the startup process for
* the targeted processor.
*/
if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
pr_debug("Setting warm reset code and vector.\n");
smpboot_setup_warm_reset_vector(start_ip);
/*
* Be paranoid about clearing APIC errors.
*/
if (APIC_INTEGRATED(boot_cpu_apic_version)) {
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
}
}
/*
* AP might wait on cpu_callout_mask in cpu_init() with
* cpu_initialized_mask set if previous attempt to online
* it timed-out. Clear cpu_initialized_mask so that after
* INIT/SIPI it could start with a clean state.
*/
cpumask_clear_cpu(cpu, cpu_initialized_mask);
smp_mb();
/*
* Wake up a CPU in difference cases:
* - Use the method in the APIC driver if it's defined
* Otherwise,
* - Use an INIT boot APIC message for APs or NMI for BSP.
*/
if (apic->wakeup_secondary_cpu)
boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
else
boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid,
cpu0_nmi_registered);
if (!boot_error) {
/*
* Wait 10s total for first sign of life from AP
*/
boot_error = -1;
timeout = jiffies + 10*HZ;
while (time_before(jiffies, timeout)) {
if (cpumask_test_cpu(cpu, cpu_initialized_mask)) {
/*
* Tell AP to proceed with initialization
*/
cpumask_set_cpu(cpu, cpu_callout_mask);
boot_error = 0;
break;
}
schedule();
}
}
if (!boot_error) {
/*
* Wait till AP completes initial initialization
*/
while (!cpumask_test_cpu(cpu, cpu_callin_mask)) {
/*
* Allow other tasks to run while we wait for the
* AP to come online. This also gives a chance
* for the MTRR work(triggered by the AP coming online)
* to be completed in the stop machine context.
*/
schedule();
}
}
/* mark "stuck" area as not stuck */
*trampoline_status = 0;
if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
/*
* Cleanup possible dangling ends...
*/
smpboot_restore_warm_reset_vector();
}
return boot_error;
}
int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int apicid = apic->cpu_present_to_apicid(cpu);
int cpu0_nmi_registered = 0;
unsigned long flags;
int err, ret = 0;
WARN_ON(irqs_disabled());
pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu);
if (apicid == BAD_APICID ||
!physid_isset(apicid, phys_cpu_present_map) ||
!apic->apic_id_valid(apicid)) {
pr_err("%s: bad cpu %d\n", __func__, cpu);
return -EINVAL;
}
/*
* Already booted CPU?
*/
if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
pr_debug("do_boot_cpu %d Already started\n", cpu);
return -ENOSYS;
}
/*
* Save current MTRR state in case it was changed since early boot
* (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
*/
mtrr_save_state();
/* x86 CPUs take themselves offline, so delayed offline is OK. */
err = cpu_check_up_prepare(cpu);
if (err && err != -EBUSY)
return err;
/* the FPU context is blank, nobody can own it */
per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
common_cpu_up(cpu, tidle);
err = do_boot_cpu(apicid, cpu, tidle, &cpu0_nmi_registered);
if (err) {
pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
ret = -EIO;
goto unreg_nmi;
}
/*
* Check TSC synchronization with the AP (keep irqs disabled
* while doing so):
*/
local_irq_save(flags);
check_tsc_sync_source(cpu);
local_irq_restore(flags);
while (!cpu_online(cpu)) {
cpu_relax();
touch_nmi_watchdog();
}
unreg_nmi:
/*
* Clean up the nmi handler. Do this after the callin and callout sync
* to avoid impact of possible long unregister time.
*/
if (cpu0_nmi_registered)
unregister_nmi_handler(NMI_LOCAL, "wake_cpu0");
return ret;
}
/**
* arch_disable_smp_support() - disables SMP support for x86 at runtime
*/
void arch_disable_smp_support(void)
{
disable_ioapic_support();
}
/*
* Fall back to non SMP mode after errors.
*
* RED-PEN audit/test this more. I bet there is more state messed up here.
*/
static __init void disable_smp(void)
{
pr_info("SMP disabled\n");
disable_ioapic_support();
init_cpu_present(cpumask_of(0));
init_cpu_possible(cpumask_of(0));
if (smp_found_config)
physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
else
physid_set_mask_of_physid(0, &phys_cpu_present_map);
cpumask_set_cpu(0, topology_sibling_cpumask(0));
cpumask_set_cpu(0, topology_core_cpumask(0));
}
enum {
SMP_OK,
SMP_NO_CONFIG,
SMP_NO_APIC,
SMP_FORCE_UP,
};
/*
* Various sanity checks.
*/
static int __init smp_sanity_check(unsigned max_cpus)
{
preempt_disable();
#if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
if (def_to_bigsmp && nr_cpu_ids > 8) {
unsigned int cpu;
unsigned nr;
pr_warn("More than 8 CPUs detected - skipping them\n"
"Use CONFIG_X86_BIGSMP\n");
nr = 0;
for_each_present_cpu(cpu) {
if (nr >= 8)
set_cpu_present(cpu, false);
nr++;
}
nr = 0;
for_each_possible_cpu(cpu) {
if (nr >= 8)
set_cpu_possible(cpu, false);
nr++;
}
nr_cpu_ids = 8;
}
#endif
if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
pr_warn("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 && !acpi_lapic) {
preempt_enable();
pr_notice("SMP motherboard not detected\n");
return SMP_NO_CONFIG;
}
/*
* 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 (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n",
boot_cpu_physical_apicid);
physid_set(hard_smp_processor_id(), phys_cpu_present_map);
}
preempt_enable();
/*
* If we couldn't find a local APIC, then get out of here now!
*/
if (APIC_INTEGRATED(boot_cpu_apic_version) &&
!boot_cpu_has(X86_FEATURE_APIC)) {
if (!disable_apic) {
pr_err("BIOS bug, local APIC #%d not detected!...\n",
boot_cpu_physical_apicid);
pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
}
return SMP_NO_APIC;
}
/*
* If SMP should be disabled, then really disable it!
*/
if (!max_cpus) {
pr_info("SMP mode deactivated\n");
return SMP_FORCE_UP;
}
return SMP_OK;
}
static void __init smp_cpu_index_default(void)
{
int i;
struct cpuinfo_x86 *c;
for_each_possible_cpu(i) {
c = &cpu_data(i);
/* mark all to hotplug */
c->cpu_index = nr_cpu_ids;
}
}
/*
* Prepare for SMP bootup. The MP table or ACPI has been read
* earlier. Just do some sanity checking here and enable APIC mode.
*/
void __init native_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int i;
smp_cpu_index_default();
/*
* Setup boot CPU information
*/
smp_store_boot_cpu_info(); /* Final full version of the data */
cpumask_copy(cpu_callin_mask, cpumask_of(0));
mb();
for_each_possible_cpu(i) {
zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
}
/*
* Set 'default' x86 topology, this matches default_topology() in that
* it has NUMA nodes as a topology level. See also
* native_smp_cpus_done().
*
* Must be done before set_cpus_sibling_map() is ran.
*/
set_sched_topology(x86_topology);
set_cpu_sibling_map(0);
switch (smp_sanity_check(max_cpus)) {
case SMP_NO_CONFIG:
disable_smp();
if (APIC_init_uniprocessor())
pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");
return;
case SMP_NO_APIC:
disable_smp();
return;
case SMP_FORCE_UP:
disable_smp();
apic_bsp_setup(false);
return;
case SMP_OK:
break;
}
if (read_apic_id() != boot_cpu_physical_apicid) {
panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
read_apic_id(), boot_cpu_physical_apicid);
/* Or can we switch back to PIC here? */
}
default_setup_apic_routing();
cpu0_logical_apicid = apic_bsp_setup(false);
pr_info("CPU0: ");
print_cpu_info(&cpu_data(0));
uv_system_init();
set_mtrr_aps_delayed_init();
smp_quirk_init_udelay();
}
void arch_enable_nonboot_cpus_begin(void)
{
set_mtrr_aps_delayed_init();
}
void arch_enable_nonboot_cpus_end(void)
{
mtrr_aps_init();
}
/*
* Early setup to make printk work.
*/
void __init native_smp_prepare_boot_cpu(void)
{
int me = smp_processor_id();
switch_to_new_gdt(me);
/* already set me in cpu_online_mask in boot_cpu_init() */
cpumask_set_cpu(me, cpu_callout_mask);
cpu_set_state_online(me);
}
void __init native_smp_cpus_done(unsigned int max_cpus)
{
pr_debug("Boot done\n");
if (x86_has_numa_in_package)
set_sched_topology(x86_numa_in_package_topology);
nmi_selftest();
impress_friends();
setup_ioapic_dest();
mtrr_aps_init();
}
static int __initdata setup_possible_cpus = -1;
static int __init _setup_possible_cpus(char *str)
{
get_option(&str, &setup_possible_cpus);
return 0;
}
early_param("possible_cpus", _setup_possible_cpus);
/*
* cpu_possible_mask should be static, it cannot change as cpu's
* are onlined, or offlined. The reason is per-cpu data-structures
* are allocated by some modules at init time, and dont expect to
* do this dynamically on cpu arrival/departure.
* cpu_present_mask on the other hand can change dynamically.
* In case when cpu_hotplug is not compiled, then we resort to current
* behaviour, which is cpu_possible == cpu_present.
* - Ashok Raj
*
* Three ways to find out the number of additional hotplug CPUs:
* - If the BIOS specified disabled CPUs in ACPI/mptables use that.
* - The user can overwrite it with possible_cpus=NUM
* - Otherwise don't reserve additional CPUs.
* We do this because additional CPUs waste a lot of memory.
* -AK
*/
__init void prefill_possible_map(void)
{
int i, possible;
/* No boot processor was found in mptable or ACPI MADT */
if (!num_processors) {
if (boot_cpu_has(X86_FEATURE_APIC)) {
int apicid = boot_cpu_physical_apicid;
int cpu = hard_smp_processor_id();
pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
/* Make sure boot cpu is enumerated */
if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
apic->apic_id_valid(apicid))
generic_processor_info(apicid, boot_cpu_apic_version);
}
if (!num_processors)
num_processors = 1;
}
i = setup_max_cpus ?: 1;
if (setup_possible_cpus == -1) {
possible = num_processors;
#ifdef CONFIG_HOTPLUG_CPU
if (setup_max_cpus)
possible += disabled_cpus;
#else
if (possible > i)
possible = i;
#endif
} else
possible = setup_possible_cpus;
total_cpus = max_t(int, possible, num_processors + disabled_cpus);
/* nr_cpu_ids could be reduced via nr_cpus= */
if (possible > nr_cpu_ids) {
pr_warn("%d Processors exceeds NR_CPUS limit of %u\n",
possible, nr_cpu_ids);
possible = nr_cpu_ids;
}
#ifdef CONFIG_HOTPLUG_CPU
if (!setup_max_cpus)
#endif
if (possible > i) {
pr_warn("%d Processors exceeds max_cpus limit of %u\n",
possible, setup_max_cpus);
possible = i;
}
nr_cpu_ids = possible;
pr_info("Allowing %d CPUs, %d hotplug CPUs\n",
possible, max_t(int, possible - num_processors, 0));
reset_cpu_possible_mask();
for (i = 0; i < possible; i++)
set_cpu_possible(i, true);
}
#ifdef CONFIG_HOTPLUG_CPU
/* Recompute SMT state for all CPUs on offline */
static void recompute_smt_state(void)
{
int max_threads, cpu;
max_threads = 0;
for_each_online_cpu (cpu) {
int threads = cpumask_weight(topology_sibling_cpumask(cpu));
if (threads > max_threads)
max_threads = threads;
}
__max_smt_threads = max_threads;
}
static void remove_siblinginfo(int cpu)
{
int sibling;
struct cpuinfo_x86 *c = &cpu_data(cpu);
for_each_cpu(sibling, topology_core_cpumask(cpu)) {
cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
/*/
* last thread sibling in this cpu core going down
*/
if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1)
cpu_data(sibling).booted_cores--;
}
for_each_cpu(sibling, topology_sibling_cpumask(cpu))
cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
cpumask_clear(cpu_llc_shared_mask(cpu));
cpumask_clear(topology_sibling_cpumask(cpu));
cpumask_clear(topology_core_cpumask(cpu));
c->phys_proc_id = 0;
c->cpu_core_id = 0;
cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
recompute_smt_state();
}
static void remove_cpu_from_maps(int cpu)
{
set_cpu_online(cpu, false);
cpumask_clear_cpu(cpu, cpu_callout_mask);
cpumask_clear_cpu(cpu, cpu_callin_mask);
/* was set by cpu_init() */
cpumask_clear_cpu(cpu, cpu_initialized_mask);
numa_remove_cpu(cpu);
}
void cpu_disable_common(void)
{
int cpu = smp_processor_id();
remove_siblinginfo(cpu);
/* It's now safe to remove this processor from the online map */
lock_vector_lock();
remove_cpu_from_maps(cpu);
unlock_vector_lock();
fixup_irqs();
}
int native_cpu_disable(void)
{
int ret;
ret = check_irq_vectors_for_cpu_disable();
if (ret)
return ret;
clear_local_APIC();
cpu_disable_common();
return 0;
}
int common_cpu_die(unsigned int cpu)
{
int ret = 0;
/* We don't do anything here: idle task is faking death itself. */
/* They ack this in play_dead() by setting CPU_DEAD */
if (cpu_wait_death(cpu, 5)) {
if (system_state == SYSTEM_RUNNING)
pr_info("CPU %u is now offline\n", cpu);
} else {
pr_err("CPU %u didn't die...\n", cpu);
ret = -1;
}
return ret;
}
void native_cpu_die(unsigned int cpu)
{
common_cpu_die(cpu);
}
void play_dead_common(void)
{
idle_task_exit();
/* Ack it */
(void)cpu_report_death();
/*
* With physical CPU hotplug, we should halt the cpu
*/
local_irq_disable();
}
static bool wakeup_cpu0(void)
{
if (smp_processor_id() == 0 && enable_start_cpu0)
return true;
return false;
}
/*
* We need to flush the caches before going to sleep, lest we have
* dirty data in our caches when we come back up.
*/
static inline void mwait_play_dead(void)
{
unsigned int eax, ebx, ecx, edx;
unsigned int highest_cstate = 0;
unsigned int highest_subcstate = 0;
void *mwait_ptr;
int i;
if (!this_cpu_has(X86_FEATURE_MWAIT))
return;
if (!this_cpu_has(X86_FEATURE_CLFLUSH))
return;
if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
return;
eax = CPUID_MWAIT_LEAF;
ecx = 0;
native_cpuid(&eax, &ebx, &ecx, &edx);
/*
* eax will be 0 if EDX enumeration is not valid.
* Initialized below to cstate, sub_cstate value when EDX is valid.
*/
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
eax = 0;
} else {
edx >>= MWAIT_SUBSTATE_SIZE;
for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
if (edx & MWAIT_SUBSTATE_MASK) {
highest_cstate = i;
highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
}
}
eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
(highest_subcstate - 1);
}
/*
* This should be a memory location in a cache line which is
* unlikely to be touched by other processors. The actual
* content is immaterial as it is not actually modified in any way.
*/
mwait_ptr = &current_thread_info()->flags;
wbinvd();
while (1) {
/*
* The CLFLUSH is a workaround for erratum AAI65 for
* the Xeon 7400 series. It's not clear it is actually
* needed, but it should be harmless in either case.
* The WBINVD is insufficient due to the spurious-wakeup
* case where we return around the loop.
*/
mb();
clflush(mwait_ptr);
mb();
__monitor(mwait_ptr, 0, 0);
mb();
__mwait(eax, 0);
/*
* If NMI wants to wake up CPU0, start CPU0.
*/
if (wakeup_cpu0())
start_cpu0();
}
}
void hlt_play_dead(void)
{
if (__this_cpu_read(cpu_info.x86) >= 4)
wbinvd();
while (1) {
native_halt();
/*
* If NMI wants to wake up CPU0, start CPU0.
*/
if (wakeup_cpu0())
start_cpu0();
}
}
void native_play_dead(void)
{
play_dead_common();
tboot_shutdown(TB_SHUTDOWN_WFS);
mwait_play_dead(); /* Only returns on failure */
if (cpuidle_play_dead())
hlt_play_dead();
}
#else /* ... !CONFIG_HOTPLUG_CPU */
int native_cpu_disable(void)
{
return -ENOSYS;
}
void native_cpu_die(unsigned int cpu)
{
/* We said "no" in __cpu_disable */
BUG();
}
void native_play_dead(void)
{
BUG();
}
#endif