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Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 1707 |
1 files changed, 1707 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c new file mode 100644 index 000000000..8783d065f --- /dev/null +++ b/arch/x86/kernel/smpboot.c @@ -0,0 +1,1707 @@ + /* + * 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/misc.h> +#include <asm/qspinlock.h> +#include <asm/intel-family.h> +#include <asm/cpu_device_id.h> +#include <asm/spec-ctrl.h> +#include <asm/hw_irq.h> + +/* 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 */ +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 __read_mostly __max_smt_threads = 1; + +/* 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); + *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = + start_eip >> 4; + *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = + start_eip & 0xf; +} + +static inline void smpboot_restore_warm_reset_vector(void) +{ + unsigned long flags; + + /* + * 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); + + /* + * The topology information must be up to date before + * calibrate_delay() and notify_cpu_starting(). + */ + set_cpu_sibling_map(raw_smp_processor_id()); + + /* + * 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); + + 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); + +#ifdef CONFIG_X86_32 + /* switch away from the initial page table */ + load_cr3(swapper_pg_dir); + /* + * Initialize the CR4 shadow before doing anything that could + * try to read it. + */ + cr4_init_shadow(); + __flush_tlb_all(); +#endif + load_current_idt(); + cpu_init(); + x86_cpuinit.early_percpu_clock_init(); + preempt_disable(); + smp_callin(); + + enable_start_cpu0 = 0; + + /* otherwise gcc will move up smp_processor_id before the cpu_init */ + barrier(); + /* + * Check TSC synchronization with the boot CPU: + */ + check_tsc_sync_target(); + + speculative_store_bypass_ht_init(); + + /* + * Lock vector_lock, set CPU online and bring the vector + * allocator online. Online must be set with vector_lock held + * to prevent a concurrent irq setup/teardown from seeing a + * half valid vector space. + */ + lock_vector_lock(); + set_cpu_online(smp_processor_id(), true); + lapic_online(); + 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); + + /* + * Prevent tail call to cpu_startup_entry() because the stack protector + * guard has been changed a couple of function calls up, in + * boot_init_stack_canary() and must not be checked before tail calling + * another function. + */ + prevent_tail_call_optimization(); +} + +/** + * topology_is_primary_thread - Check whether CPU is the primary SMT thread + * @cpu: CPU to check + */ +bool topology_is_primary_thread(unsigned int cpu) +{ + return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu)); +} + +/** + * topology_smt_supported - Check whether SMT is supported by the CPUs + */ +bool topology_smt_supported(void) +{ + return smp_num_siblings > 1; +} + +/** + * 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) +{ + int cpu; + + for_each_possible_cpu(cpu) { + struct cpuinfo_x86 *c = &cpu_data(cpu); + + if (c->initialized && c->phys_proc_id == phys_pkg) + return c->logical_proc_id; + } + return -1; +} +EXPORT_SYMBOL(topology_phys_to_logical_pkg); + +/** + * 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) +{ + int new; + + /* Already available somewhere? */ + new = topology_phys_to_logical_pkg(pkg); + if (new >= 0) + goto found; + + new = logical_packages++; + if (new != pkg) { + pr_info("CPU %u Converting physical %u to logical package %u\n", + cpu, pkg, new); + } +found: + cpu_data(cpu).logical_proc_id = new; + return 0; +} + +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; + topology_update_package_map(c->phys_proc_id, id); + c->initialized = true; +} + +/* + * 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); + + /* Copy boot_cpu_data only on the first bringup */ + if (!c->initialized) + *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); + c->initialized = true; +} + +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; +} + +/* + * Define snc_cpu[] for SNC (Sub-NUMA Cluster) CPUs. + * + * These are Intel CPUs that enumerate an LLC that is shared by + * multiple NUMA nodes. The LLC on these systems is shared for + * off-package data access but private to the NUMA node (half + * of the package) for on-package access. + * + * CPUID (the source of the information about the LLC) can only + * enumerate the cache as being shared *or* unshared, but not + * this particular configuration. The CPU in this case enumerates + * the cache to be shared across the entire package (spanning both + * NUMA nodes). + */ + +static const struct x86_cpu_id snc_cpu[] = { + { X86_VENDOR_INTEL, 6, INTEL_FAM6_SKYLAKE_X }, + {} +}; + +static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) +{ + int cpu1 = c->cpu_index, cpu2 = o->cpu_index; + + /* Do not match if we do not have a valid APICID for cpu: */ + if (per_cpu(cpu_llc_id, cpu1) == BAD_APICID) + return false; + + /* Do not match if LLC id does not match: */ + if (per_cpu(cpu_llc_id, cpu1) != per_cpu(cpu_llc_id, cpu2)) + return false; + + /* + * Allow the SNC topology without warning. Return of false + * means 'c' does not share the LLC of 'o'. This will be + * reflected to userspace. + */ + if (!topology_same_node(c, o) && x86_match_cpu(snc_cpu)) + return false; + + return topology_sane(c, o, "llc"); +} + +/* + * 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, Intel Cluster-on-Die, and Intel + * Sub-NUMA Clustering 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) = task_top_of_stack(idle); +#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 */ + init_espfix_ap(cpu); + + /* So we see what's up */ + announce_cpu(cpu, apicid); + + /* + * This grunge runs the startup process for + * the targeted processor. + */ + + if (x86_platform.legacy.warm_reset) { + + 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 (x86_platform.legacy.warm_reset) { + /* + * 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; + + lockdep_assert_irqs_enabled(); + + 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)); +} + +/* + * Various sanity checks. + */ +static void __init smp_sanity_check(void) +{ + 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); + } + + /* + * 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(); +} + +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; + } +} + +static void __init smp_get_logical_apicid(void) +{ + if (x2apic_mode) + cpu0_logical_apicid = apic_read(APIC_LDR); + else + cpu0_logical_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR)); +} + +/* + * Prepare for SMP bootup. + * @max_cpus: configured maximum number of CPUs, It is a legacy parameter + * for common interface support. + */ +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); + + smp_sanity_check(); + + switch (apic_intr_mode) { + case APIC_PIC: + case APIC_VIRTUAL_WIRE_NO_CONFIG: + disable_smp(); + return; + case APIC_SYMMETRIC_IO_NO_ROUTING: + disable_smp(); + /* Setup local timer */ + x86_init.timers.setup_percpu_clockev(); + return; + case APIC_VIRTUAL_WIRE: + case APIC_SYMMETRIC_IO: + break; + } + + /* Setup local timer */ + x86_init.timers.setup_percpu_clockev(); + + smp_get_logical_apicid(); + + pr_info("CPU0: "); + print_cpu_info(&cpu_data(0)); + + native_pv_lock_init(); + + uv_system_init(); + + set_mtrr_aps_delayed_init(); + + smp_quirk_init_udelay(); + + speculative_store_bypass_ht_init(); +} + +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 calculate_max_logical_packages(void) +{ + int ncpus; + + /* + * Today neither Intel nor AMD support heterogenous systems so + * extrapolate the boot cpu's data to all packages. + */ + ncpus = cpu_data(0).booted_cores * topology_max_smt_threads(); + __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); + pr_info("Max logical packages: %u\n", __max_logical_packages); +} + +void __init native_smp_cpus_done(unsigned int max_cpus) +{ + pr_debug("Boot done\n"); + + calculate_max_logical_packages(); + + if (x86_has_numa_in_package) + set_sched_topology(x86_numa_in_package_topology); + + nmi_selftest(); + impress_friends(); + 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->cpu_core_id = 0; + c->booted_cores = 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(); + lapic_offline(); +} + +int native_cpu_disable(void) +{ + int ret; + + ret = lapic_can_unplug_cpu(); + 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 (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + return; + 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 = ¤t_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 |