X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fi386%2Fkernel%2Fsmpboot.c;h=825b2b4ca721a1c931abb2114afd0483c6c3a1ae;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=1ce7180fef2a2adb059d307fb4a3e5dfaa641490;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index 1ce7180fe..825b2b4ca 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -42,8 +42,10 @@ #include #include #include -#include #include +#include +#include +#include #include #include @@ -56,26 +58,53 @@ #include /* Set if we find a B stepping CPU */ -static int __initdata smp_b_stepping; +static int __devinitdata smp_b_stepping; /* Number of siblings per CPU package */ int smp_num_siblings = 1; -int phys_proc_id[NR_CPUS]; /* Package ID of each logical CPU */ -EXPORT_SYMBOL(phys_proc_id); -int cpu_core_id[NR_CPUS]; /* Core ID of each logical CPU */ -EXPORT_SYMBOL(cpu_core_id); +#ifdef CONFIG_X86_HT +EXPORT_SYMBOL(smp_num_siblings); +#endif + +/* Package ID of each logical CPU */ +int phys_proc_id[NR_CPUS] __read_mostly = {[0 ... NR_CPUS-1] = BAD_APICID}; + +/* Core ID of each logical CPU */ +int cpu_core_id[NR_CPUS] __read_mostly = {[0 ... NR_CPUS-1] = BAD_APICID}; + +/* Last level cache ID of each logical CPU */ +int cpu_llc_id[NR_CPUS] __cpuinitdata = {[0 ... NR_CPUS-1] = BAD_APICID}; + +/* representing HT siblings of each logical CPU */ +cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly; +EXPORT_SYMBOL(cpu_sibling_map); + +/* representing HT and core siblings of each logical CPU */ +cpumask_t cpu_core_map[NR_CPUS] __read_mostly; +EXPORT_SYMBOL(cpu_core_map); /* bitmap of online cpus */ -cpumask_t cpu_online_map; +cpumask_t cpu_online_map __read_mostly; +EXPORT_SYMBOL(cpu_online_map); cpumask_t cpu_callin_map; cpumask_t cpu_callout_map; +EXPORT_SYMBOL(cpu_callout_map); +cpumask_t cpu_possible_map; +EXPORT_SYMBOL(cpu_possible_map); static cpumask_t smp_commenced_mask; +/* TSC's upper 32 bits can't be written in eariler CPU (before prescott), there + * is no way to resync one AP against BP. TBD: for prescott and above, we + * should use IA64's algorithm + */ +static int __devinitdata tsc_sync_disabled; + /* Per CPU bogomips and other parameters */ struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; +EXPORT_SYMBOL(cpu_data); -u8 x86_cpu_to_apicid[NR_CPUS] = +u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0xff }; EXPORT_SYMBOL(x86_cpu_to_apicid); @@ -90,13 +119,16 @@ static int trampoline_exec; static void map_cpu_to_logical_apicid(void); +/* State of each CPU. */ +DEFINE_PER_CPU(int, cpu_state) = { 0 }; + /* * 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) +static unsigned long __devinit setup_trampoline(void) { memcpy(trampoline_base, trampoline_data, trampoline_end - trampoline_data); return virt_to_phys(trampoline_base); @@ -126,7 +158,7 @@ void __init smp_alloc_memory(void) * a given CPU */ -static void __init smp_store_cpu_info(int id) +static void __devinit smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = cpu_data + id; @@ -172,7 +204,7 @@ static void __init smp_store_cpu_info(int id) goto valid_k7; /* If we get here, it's not a certified SMP capable AMD system. */ - tainted |= TAINT_UNSAFE_SMP; + add_taint(TAINT_UNSAFE_SMP); } valid_k7: @@ -199,7 +231,7 @@ static void __init synchronize_tsc_bp (void) unsigned long long t0; unsigned long long sum, avg; long long delta; - unsigned long one_usec; + unsigned int one_usec; int buggy = 0; printk(KERN_INFO "checking TSC synchronization across %u CPUs: ", num_booting_cpus()); @@ -281,7 +313,9 @@ static void __init synchronize_tsc_bp (void) if (tsc_values[i] < avg) realdelta = -realdelta; - printk(KERN_INFO "CPU#%d had %ld usecs TSC skew, fixed it up.\n", i, realdelta); + if (realdelta > 0) + printk(KERN_INFO "CPU#%d had %ld usecs TSC " + "skew, fixed it up.\n", i, realdelta); } sum += delta; @@ -320,7 +354,7 @@ extern void calibrate_delay(void); static atomic_t init_deasserted; -static void __init smp_callin(void) +static void __devinit smp_callin(void) { int cpuid, phys_id; unsigned long timeout; @@ -405,16 +439,94 @@ static void __init smp_callin(void) /* * Synchronize the TSC with the BP */ - if (cpu_has_tsc && cpu_khz) + if (cpu_has_tsc && cpu_khz && !tsc_sync_disabled) synchronize_tsc_ap(); } static int cpucount; +/* maps the cpu to the sched domain representing multi-core */ +cpumask_t cpu_coregroup_map(int cpu) +{ + struct cpuinfo_x86 *c = cpu_data + cpu; + /* + * For perf, we return last level cache shared map. + * TBD: when power saving sched policy is added, we will return + * cpu_core_map when power saving policy is enabled + */ + return c->llc_shared_map; +} + +/* representing cpus for which sibling maps can be computed */ +static cpumask_t cpu_sibling_setup_map; + +static inline void +set_cpu_sibling_map(int cpu) +{ + int i; + struct cpuinfo_x86 *c = cpu_data; + + cpu_set(cpu, cpu_sibling_setup_map); + + if (smp_num_siblings > 1) { + for_each_cpu_mask(i, cpu_sibling_setup_map) { + if (phys_proc_id[cpu] == phys_proc_id[i] && + cpu_core_id[cpu] == cpu_core_id[i]) { + cpu_set(i, cpu_sibling_map[cpu]); + cpu_set(cpu, cpu_sibling_map[i]); + cpu_set(i, cpu_core_map[cpu]); + cpu_set(cpu, cpu_core_map[i]); + cpu_set(i, c[cpu].llc_shared_map); + cpu_set(cpu, c[i].llc_shared_map); + } + } + } else { + cpu_set(cpu, cpu_sibling_map[cpu]); + } + + cpu_set(cpu, c[cpu].llc_shared_map); + + if (current_cpu_data.x86_max_cores == 1) { + cpu_core_map[cpu] = cpu_sibling_map[cpu]; + c[cpu].booted_cores = 1; + return; + } + + for_each_cpu_mask(i, cpu_sibling_setup_map) { + if (cpu_llc_id[cpu] != BAD_APICID && + cpu_llc_id[cpu] == cpu_llc_id[i]) { + cpu_set(i, c[cpu].llc_shared_map); + cpu_set(cpu, c[i].llc_shared_map); + } + if (phys_proc_id[cpu] == phys_proc_id[i]) { + cpu_set(i, cpu_core_map[cpu]); + cpu_set(cpu, cpu_core_map[i]); + /* + * Does this new cpu bringup a new core? + */ + if (cpus_weight(cpu_sibling_map[cpu]) == 1) { + /* + * for each core in package, increment + * the booted_cores for this new cpu + */ + if (first_cpu(cpu_sibling_map[i]) == i) + c[cpu].booted_cores++; + /* + * increment the core count for all + * the other cpus in this package + */ + if (i != cpu) + c[i].booted_cores++; + } else if (i != cpu && !c[cpu].booted_cores) + c[cpu].booted_cores = c[i].booted_cores; + } + } +} + /* * Activate a secondary processor. */ -static void __init start_secondary(void *unused) +static void __devinit start_secondary(void *unused) { /* * Dont put anything before smp_callin(), SMP @@ -422,6 +534,7 @@ static void __init start_secondary(void *unused) * things done here to the most necessary things. */ cpu_init(); + preempt_disable(); smp_callin(); while (!cpu_isset(smp_processor_id(), smp_commenced_mask)) rep_nop(); @@ -437,7 +550,23 @@ static void __init start_secondary(void *unused) * the local TLBs too. */ local_flush_tlb(); + + /* This must be done before setting cpu_online_map */ + set_cpu_sibling_map(raw_smp_processor_id()); + wmb(); + + /* + * We need to hold call_lock, so there is no inconsistency + * between the time smp_call_function() determines number of + * IPI receipients, and the time when the determination is made + * for which cpus receive the IPI. Holding this + * lock helps us to not include this cpu in a currently in progress + * smp_call_function(). + */ + lock_ipi_call_lock(); cpu_set(smp_processor_id(), cpu_online_map); + unlock_ipi_call_lock(); + per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; /* We can take interrupts now: we're officially "up". */ local_irq_enable(); @@ -452,7 +581,7 @@ static void __init start_secondary(void *unused) * from the task structure * This function must not return. */ -void __init initialize_secondary(void) +void __devinit initialize_secondary(void) { /* * We don't actually need to load the full TSS, @@ -474,10 +603,10 @@ extern struct { #ifdef CONFIG_NUMA /* which logical CPUs are on which nodes */ -cpumask_t node_2_cpu_mask[MAX_NUMNODES] = +cpumask_t node_2_cpu_mask[MAX_NUMNODES] __read_mostly = { [0 ... MAX_NUMNODES-1] = CPU_MASK_NONE }; /* which node each logical CPU is on */ -int cpu_2_node[NR_CPUS] = { [0 ... NR_CPUS-1] = 0 }; +int cpu_2_node[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 }; EXPORT_SYMBOL(cpu_2_node); /* set up a mapping between cpu and node. */ @@ -505,7 +634,7 @@ static inline void unmap_cpu_to_node(int cpu) #endif /* CONFIG_NUMA */ -u8 cpu_2_logical_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID }; +u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID }; static void map_cpu_to_logical_apicid(void) { @@ -531,7 +660,7 @@ static inline void __inquire_remote_apic(int apicid) printk("Inquiring remote APIC #%d...\n", apicid); - for (i = 0; i < sizeof(regs) / sizeof(*regs); i++) { + for (i = 0; i < ARRAY_SIZE(regs); i++) { printk("... APIC #%d %s: ", apicid, names[i]); /* @@ -566,7 +695,7 @@ static inline void __inquire_remote_apic(int apicid) * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this * won't ... remember to clear down the APIC, etc later. */ -static int __init +static int __devinit wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip) { unsigned long send_status = 0, accept_status = 0; @@ -612,7 +741,7 @@ wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip) #endif /* WAKE_SECONDARY_VIA_NMI */ #ifdef WAKE_SECONDARY_VIA_INIT -static int __init +static int __devinit wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip) { unsigned long send_status = 0, accept_status = 0; @@ -747,8 +876,42 @@ wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip) #endif /* WAKE_SECONDARY_VIA_INIT */ extern cpumask_t cpu_initialized; +static inline int alloc_cpu_id(void) +{ + cpumask_t tmp_map; + int cpu; + cpus_complement(tmp_map, cpu_present_map); + cpu = first_cpu(tmp_map); + if (cpu >= NR_CPUS) + return -ENODEV; + return cpu; +} + +#ifdef CONFIG_HOTPLUG_CPU +static struct task_struct * __devinitdata cpu_idle_tasks[NR_CPUS]; +static inline struct task_struct * alloc_idle_task(int cpu) +{ + struct task_struct *idle; -static int __init do_boot_cpu(int apicid) + if ((idle = cpu_idle_tasks[cpu]) != NULL) { + /* initialize thread_struct. we really want to avoid destroy + * idle tread + */ + idle->thread.esp = (unsigned long)task_pt_regs(idle); + init_idle(idle, cpu); + return idle; + } + idle = fork_idle(cpu); + + if (!IS_ERR(idle)) + cpu_idle_tasks[cpu] = idle; + return idle; +} +#else +#define alloc_idle_task(cpu) fork_idle(cpu) +#endif + +static int __devinit do_boot_cpu(int apicid, int cpu) /* * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad * (ie clustered apic addressing mode), this is a LOGICAL apic ID. @@ -757,16 +920,18 @@ static int __init do_boot_cpu(int apicid) { struct task_struct *idle; unsigned long boot_error; - int timeout, cpu; + int timeout; unsigned long start_eip; unsigned short nmi_high = 0, nmi_low = 0; - cpu = ++cpucount; + ++cpucount; + alternatives_smp_switch(1); + /* * We can't use kernel_thread since we must avoid to * reschedule the child. */ - idle = fork_idle(cpu); + idle = alloc_idle_task(cpu); if (IS_ERR(idle)) panic("failed fork for CPU %d", cpu); idle->thread.eip = (unsigned long) start_secondary; @@ -833,13 +998,16 @@ static int __init do_boot_cpu(int apicid) inquire_remote_apic(apicid); } } - x86_cpu_to_apicid[cpu] = apicid; + if (boot_error) { /* Try to put things back the way they were before ... */ unmap_cpu_to_logical_apicid(cpu); cpu_clear(cpu, cpu_callout_map); /* was set here (do_boot_cpu()) */ cpu_clear(cpu, cpu_initialized); /* was set by cpu_init() */ cpucount--; + } else { + x86_cpu_to_apicid[cpu] = apicid; + cpu_set(cpu, cpu_present_map); } /* mark "stuck" area as not stuck */ @@ -848,6 +1016,72 @@ static int __init do_boot_cpu(int apicid) return boot_error; } +#ifdef CONFIG_HOTPLUG_CPU +void cpu_exit_clear(void) +{ + int cpu = raw_smp_processor_id(); + + idle_task_exit(); + + cpucount --; + cpu_uninit(); + irq_ctx_exit(cpu); + + cpu_clear(cpu, cpu_callout_map); + cpu_clear(cpu, cpu_callin_map); + + cpu_clear(cpu, smp_commenced_mask); + unmap_cpu_to_logical_apicid(cpu); +} + +struct warm_boot_cpu_info { + struct completion *complete; + int apicid; + int cpu; +}; + +static void __cpuinit do_warm_boot_cpu(void *p) +{ + struct warm_boot_cpu_info *info = p; + do_boot_cpu(info->apicid, info->cpu); + complete(info->complete); +} + +static int __cpuinit __smp_prepare_cpu(int cpu) +{ + DECLARE_COMPLETION(done); + struct warm_boot_cpu_info info; + struct work_struct task; + int apicid, ret; + + apicid = x86_cpu_to_apicid[cpu]; + if (apicid == BAD_APICID) { + ret = -ENODEV; + goto exit; + } + + info.complete = &done; + info.apicid = apicid; + info.cpu = cpu; + INIT_WORK(&task, do_warm_boot_cpu, &info); + + tsc_sync_disabled = 1; + + /* init low mem mapping */ + clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS, + KERNEL_PGD_PTRS); + flush_tlb_all(); + schedule_work(&task); + wait_for_completion(&done); + + tsc_sync_disabled = 0; + zap_low_mappings(); + ret = 0; +exit: + return ret; +} +#endif + static void smp_tune_scheduling (void) { unsigned long cachesize; /* kB */ @@ -875,6 +1109,7 @@ static void smp_tune_scheduling (void) cachesize = 16; /* Pentiums, 2x8kB cache */ bandwidth = 100; } + max_cache_size = cachesize * 1024; } } @@ -885,10 +1120,9 @@ static void smp_tune_scheduling (void) static int boot_cpu_logical_apicid; /* Where the IO area was mapped on multiquad, always 0 otherwise */ void *xquad_portio; - -cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned; -cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned; -EXPORT_SYMBOL(cpu_core_map); +#ifdef CONFIG_X86_NUMAQ +EXPORT_SYMBOL(xquad_portio); +#endif static void __init smp_boot_cpus(unsigned int max_cpus) { @@ -908,11 +1142,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus) current_thread_info()->cpu = 0; smp_tune_scheduling(); - cpus_clear(cpu_sibling_map[0]); - cpu_set(0, cpu_sibling_map[0]); - cpus_clear(cpu_core_map[0]); - cpu_set(0, cpu_core_map[0]); + set_cpu_sibling_map(0); /* * If we couldn't find an SMP configuration at boot time, @@ -1001,7 +1232,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus) if (max_cpus <= cpucount+1) continue; - if (do_boot_cpu(apicid)) + if (((cpu = alloc_cpu_id()) <= 0) || do_boot_cpu(apicid, cpu)) printk("CPU #%d not responding - cannot use it.\n", apicid); else @@ -1023,8 +1254,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus) printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n", cpucount+1, - HZ*(bogosum >> 3)/62500, - (HZ*(bogosum >> 3)/625) % 100); + bogosum/(500000/HZ), + (bogosum/(5000/HZ))%100); Dprintk("Before bogocount - setting activated=1.\n"); @@ -1053,44 +1284,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus) cpus_clear(cpu_core_map[cpu]); } - for (cpu = 0; cpu < NR_CPUS; cpu++) { - struct cpuinfo_x86 *c = cpu_data + cpu; - int siblings = 0; - int i; - if (!cpu_isset(cpu, cpu_callout_map)) - continue; - - if (smp_num_siblings > 1) { - for (i = 0; i < NR_CPUS; i++) { - if (!cpu_isset(i, cpu_callout_map)) - continue; - if (cpu_core_id[cpu] == cpu_core_id[i]) { - siblings++; - cpu_set(i, cpu_sibling_map[cpu]); - } - } - } else { - siblings++; - cpu_set(cpu, cpu_sibling_map[cpu]); - } - - if (siblings != smp_num_siblings) { - printk(KERN_WARNING "WARNING: %d siblings found for CPU%d, should be %d\n", siblings, cpu, smp_num_siblings); - smp_num_siblings = siblings; - } - - if (c->x86_num_cores > 1) { - for (i = 0; i < NR_CPUS; i++) { - if (!cpu_isset(i, cpu_callout_map)) - continue; - if (phys_proc_id[cpu] == phys_proc_id[i]) { - cpu_set(i, cpu_core_map[cpu]); - } - } - } else { - cpu_core_map[cpu] = cpu_sibling_map[cpu]; - } - } + cpu_set(0, cpu_sibling_map[0]); + cpu_set(0, cpu_core_map[0]); smpboot_setup_io_apic(); @@ -1107,6 +1302,9 @@ static void __init smp_boot_cpus(unsigned int max_cpus) who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */ void __init smp_prepare_cpus(unsigned int max_cpus) { + smp_commenced_mask = cpumask_of_cpu(0); + cpu_callin_map = cpumask_of_cpu(0); + mb(); smp_boot_cpus(max_cpus); } @@ -1114,23 +1312,124 @@ void __devinit smp_prepare_boot_cpu(void) { cpu_set(smp_processor_id(), cpu_online_map); cpu_set(smp_processor_id(), cpu_callout_map); + cpu_set(smp_processor_id(), cpu_present_map); + cpu_set(smp_processor_id(), cpu_possible_map); + per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; } -int __devinit __cpu_up(unsigned int cpu) +#ifdef CONFIG_HOTPLUG_CPU +static void +remove_siblinginfo(int cpu) { - /* This only works at boot for x86. See "rewrite" above. */ - if (cpu_isset(cpu, smp_commenced_mask)) { - local_irq_enable(); - return -ENOSYS; + int sibling; + struct cpuinfo_x86 *c = cpu_data; + + for_each_cpu_mask(sibling, cpu_core_map[cpu]) { + cpu_clear(cpu, cpu_core_map[sibling]); + /* + * last thread sibling in this cpu core going down + */ + if (cpus_weight(cpu_sibling_map[cpu]) == 1) + c[sibling].booted_cores--; } + + for_each_cpu_mask(sibling, cpu_sibling_map[cpu]) + cpu_clear(cpu, cpu_sibling_map[sibling]); + cpus_clear(cpu_sibling_map[cpu]); + cpus_clear(cpu_core_map[cpu]); + phys_proc_id[cpu] = BAD_APICID; + cpu_core_id[cpu] = BAD_APICID; + cpu_clear(cpu, cpu_sibling_setup_map); +} + +int __cpu_disable(void) +{ + cpumask_t map = cpu_online_map; + int cpu = smp_processor_id(); + + /* + * Perhaps use cpufreq to drop frequency, but that could go + * into generic code. + * + * We won't take down the boot processor on i386 due to some + * interrupts only being able to be serviced by the BSP. + * Especially so if we're not using an IOAPIC -zwane + */ + if (cpu == 0) + return -EBUSY; + + clear_local_APIC(); + /* Allow any queued timer interrupts to get serviced */ + local_irq_enable(); + mdelay(1); + local_irq_disable(); + + remove_siblinginfo(cpu); + + cpu_clear(cpu, map); + fixup_irqs(map); + /* It's now safe to remove this processor from the online map */ + cpu_clear(cpu, cpu_online_map); + return 0; +} + +void __cpu_die(unsigned int cpu) +{ + /* We don't do anything here: idle task is faking death itself. */ + unsigned int i; + + for (i = 0; i < 10; i++) { + /* They ack this in play_dead by setting CPU_DEAD */ + if (per_cpu(cpu_state, cpu) == CPU_DEAD) { + printk ("CPU %d is now offline\n", cpu); + if (1 == num_online_cpus()) + alternatives_smp_switch(0); + return; + } + msleep(100); + } + printk(KERN_ERR "CPU %u didn't die...\n", cpu); +} +#else /* ... !CONFIG_HOTPLUG_CPU */ +int __cpu_disable(void) +{ + return -ENOSYS; +} + +void __cpu_die(unsigned int cpu) +{ + /* We said "no" in __cpu_disable */ + BUG(); +} +#endif /* CONFIG_HOTPLUG_CPU */ + +int __devinit __cpu_up(unsigned int cpu) +{ +#ifdef CONFIG_HOTPLUG_CPU + int ret=0; + + /* + * We do warm boot only on cpus that had booted earlier + * Otherwise cold boot is all handled from smp_boot_cpus(). + * cpu_callin_map is set during AP kickstart process. Its reset + * when a cpu is taken offline from cpu_exit_clear(). + */ + if (!cpu_isset(cpu, cpu_callin_map)) + ret = __smp_prepare_cpu(cpu); + + if (ret) + return -EIO; +#endif /* In case one didn't come up */ if (!cpu_isset(cpu, cpu_callin_map)) { + printk(KERN_DEBUG "skipping cpu%d, didn't come online\n", cpu); local_irq_enable(); return -EIO; } local_irq_enable(); + per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; /* Unleash the CPU! */ cpu_set(cpu, smp_commenced_mask); while (!cpu_isset(cpu, cpu_online_map)) @@ -1144,10 +1443,12 @@ void __init smp_cpus_done(unsigned int max_cpus) setup_ioapic_dest(); #endif zap_low_mappings(); +#ifndef CONFIG_HOTPLUG_CPU /* * Disable executability of the SMP trampoline: */ set_kernel_exec((unsigned long)trampoline_base, trampoline_exec); +#endif } void __init smp_intr_init(void)