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/*

 *  arch/s390/kernel/smp.c

 *

 *    Copyright IBM Corp. 1999,2007

 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),

 *               Martin Schwidefsky (schwidefsky@de.ibm.com)

 *               Heiko Carstens (heiko.carstens@de.ibm.com)

 *

 *  based on other smp stuff by

 *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>

 *    (c) 1998 Ingo Molnar

 *

 * We work with logical cpu numbering everywhere we can. The only

 * functions using the real cpu address (got from STAP) are the sigp

 * functions. For all other functions we use the identity mapping.

 * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is

 * used e.g. to find the idle task belonging to a logical cpu. Every array

 * in the kernel is sorted by the logical cpu number and not by the physical

 * one which is causing all the confusion with __cpu_logical_map and

 * cpu_number_map in other architectures.

 */

#include <linux/module.h>

#include <linux/init.h>

#include <linux/mm.h>

#include <linux/err.h>

#include <linux/spinlock.h>

#include <linux/kernel_stat.h>

#include <linux/delay.h>

#include <linux/cache.h>

#include <linux/interrupt.h>

#include <linux/cpu.h>

#include <linux/timex.h>

#include <linux/bootmem.h>

#include <asm/ipl.h>

#include <asm/setup.h>

#include <asm/sigp.h>

#include <asm/pgalloc.h>

#include <asm/irq.h>

#include <asm/s390_ext.h>

#include <asm/cpcmd.h>

#include <asm/tlbflush.h>

#include <asm/timer.h>

#include <asm/lowcore.h>

#include <asm/cpu.h>

/*

 * An array with a pointer the lowcore of every CPU.

 */

struct _lowcore *lowcore_ptr[NR_CPUS];

EXPORT_SYMBOL(lowcore_ptr);

cpumask_t cpu_online_map = CPU_MASK_NONE;

EXPORT_SYMBOL(cpu_online_map);

cpumask_t cpu_possible_map = CPU_MASK_NONE;

EXPORT_SYMBOL(cpu_possible_map);

static struct task_struct *current_set[NR_CPUS];

static void smp_ext_bitcall(int, ec_bit_sig);

/*

 * Structure and data for __smp_call_function_map(). This is designed to

 * minimise static memory requirements. It also looks cleaner.

 */

static DEFINE_SPINLOCK(call_lock);

struct call_data_struct {

        void (*func) (void *info);

        void *info;

        cpumask_t started;

        cpumask_t finished;

        int wait;

};

static struct call_data_struct *call_data;

/*

 * 'Call function' interrupt callback

 */

static void do_call_function(void)

{

        void (*func) (void *info) = call_data->func;

        void *info = call_data->info;

        int wait = call_data->wait;

        cpu_set(smp_processor_id(), call_data->started);

        (*func)(info);

        if (wait)

                cpu_set(smp_processor_id(), call_data->finished);;

}

static void __smp_call_function_map(void (*func) (void *info), void *info,

                                    int nonatomic, int wait, cpumask_t map)

{

        struct call_data_struct data;

        int cpu, local = 0;

        /*

         * Can deadlock when interrupts are disabled or if in wrong context.

         */

        WARN_ON(irqs_disabled() || in_irq());

        /*

         * Check for local function call. We have to have the same call order

         * as in on_each_cpu() because of machine_restart_smp().

         */

        if (cpu_isset(smp_processor_id(), map)) {

                local = 1;

                cpu_clear(smp_processor_id(), map);

        }

        cpus_and(map, map, cpu_online_map);

        if (cpus_empty(map))

                goto out;

        data.func = func;

        data.info = info;

        data.started = CPU_MASK_NONE;

        data.wait = wait;

        if (wait)

                data.finished = CPU_MASK_NONE;

        spin_lock(&call_lock);

        call_data = &data;

        for_each_cpu_mask(cpu, map)

                smp_ext_bitcall(cpu, ec_call_function);

        /* Wait for response */

        while (!cpus_equal(map, data.started))

                cpu_relax();

        if (wait)

                while (!cpus_equal(map, data.finished))

                        cpu_relax();

        spin_unlock(&call_lock);

out:

        if (local) {

                local_irq_disable();

                func(info);

                local_irq_enable();

        }

}

/*

 * smp_call_function:

 * @func: the function to run; this must be fast and non-blocking

 * @info: an arbitrary pointer to pass to the function

 * @nonatomic: unused

 * @wait: if true, wait (atomically) until function has completed on other CPUs

 *

 * Run a function on all other CPUs.

 *

 * You must not call this function with disabled interrupts, from a

 * hardware interrupt handler or from a bottom half.

 */

int smp_call_function(void (*func) (void *info), void *info, int nonatomic,

                      int wait)

{

        cpumask_t map;

        preempt_disable();

        map = cpu_online_map;

        cpu_clear(smp_processor_id(), map);

        __smp_call_function_map(func, info, nonatomic, wait, map);

        preempt_enable();

        return 0;

}

EXPORT_SYMBOL(smp_call_function);

/*

 * smp_call_function_single:

 * @cpu: the CPU where func should run

 * @func: the function to run; this must be fast and non-blocking

 * @info: an arbitrary pointer to pass to the function

 * @nonatomic: unused

 * @wait: if true, wait (atomically) until function has completed on other CPUs

 *

 * Run a function on one processor.

 *

 * You must not call this function with disabled interrupts, from a

 * hardware interrupt handler or from a bottom half.

 */

int smp_call_function_single(int cpu, void (*func) (void *info), void *info,

                             int nonatomic, int wait)

{

        preempt_disable();

        __smp_call_function_map(func, info, nonatomic, wait,

                                cpumask_of_cpu(cpu));

        preempt_enable();

        return 0;

}

EXPORT_SYMBOL(smp_call_function_single);

void smp_send_stop(void)

{

        int cpu, rc;

        /* Disable all interrupts/machine checks */

        __load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);

        /* write magic number to zero page (absolute 0) */

        lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;

        /* stop all processors */

        for_each_online_cpu(cpu) {

                if (cpu == smp_processor_id())

                        continue;

                do {

                        rc = signal_processor(cpu, sigp_stop);

                } while (rc == sigp_busy);

                while (!smp_cpu_not_running(cpu))

                        cpu_relax();

        }

}

/*

 * Reboot, halt and power_off routines for SMP.

 */

void machine_restart_smp(char *__unused)

{

        smp_send_stop();

        do_reipl();

}

void machine_halt_smp(void)

{

        smp_send_stop();

        if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)

                __cpcmd(vmhalt_cmd, NULL, 0, NULL);

        signal_processor(smp_processor_id(), sigp_stop_and_store_status);

        for (;;);

}

void machine_power_off_smp(void)

{

        smp_send_stop();

        if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)

                __cpcmd(vmpoff_cmd, NULL, 0, NULL);

        signal_processor(smp_processor_id(), sigp_stop_and_store_status);

        for (;;);

}

/*

 * This is the main routine where commands issued by other

 * cpus are handled.

 */

static void do_ext_call_interrupt(__u16 code)

{

        unsigned long bits;

        /*

         * handle bit signal external calls

         *

         * For the ec_schedule signal we have to do nothing. All the work

         * is done automatically when we return from the interrupt.

         */

        bits = xchg(&S390_lowcore.ext_call_fast, 0);

        if (test_bit(ec_call_function, &bits))

                do_call_function();

}

/*

 * Send an external call sigp to another cpu and return without waiting

 * for its completion.

 */

static void smp_ext_bitcall(int cpu, ec_bit_sig sig)

{

        /*

         * Set signaling bit in lowcore of target cpu and kick it

         */

        set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);

        while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)

                udelay(10);

}

#ifndef CONFIG_64BIT

/*

 * this function sends a 'purge tlb' signal to another CPU.

 */

void smp_ptlb_callback(void *info)

{

        __tlb_flush_local();

}

void smp_ptlb_all(void)

{

        on_each_cpu(smp_ptlb_callback, NULL, 0, 1);

}

EXPORT_SYMBOL(smp_ptlb_all);

#endif /* ! CONFIG_64BIT */

/*

 * this function sends a 'reschedule' IPI to another CPU.

 * it goes straight through and wastes no time serializing

 * anything. Worst case is that we lose a reschedule ...

 */

void smp_send_reschedule(int cpu)

{

        smp_ext_bitcall(cpu, ec_schedule);

}

/*

 * parameter area for the set/clear control bit callbacks

 */

struct ec_creg_mask_parms {

        unsigned long orvals[16];

        unsigned long andvals[16];

};

/*

 * callback for setting/clearing control bits

 */

static void smp_ctl_bit_callback(void *info)

{

        struct ec_creg_mask_parms *pp = info;

        unsigned long cregs[16];

        int i;

        __ctl_store(cregs, 0, 15);

        for (i = 0; i <= 15; i++)

                cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];

        __ctl_load(cregs, 0, 15);

}

/*

 * Set a bit in a control register of all cpus

 */

void smp_ctl_set_bit(int cr, int bit)

{

        struct ec_creg_mask_parms parms;

        memset(&parms.orvals, 0, sizeof(parms.orvals));

        memset(&parms.andvals, 0xff, sizeof(parms.andvals));

        parms.orvals[cr] = 1 << bit;

        on_each_cpu(smp_ctl_bit_callback, &parms, 0, 1);

}

EXPORT_SYMBOL(smp_ctl_set_bit);

/*

 * Clear a bit in a control register of all cpus

 */

void smp_ctl_clear_bit(int cr, int bit)

{

        struct ec_creg_mask_parms parms;

        memset(&parms.orvals, 0, sizeof(parms.orvals));

        memset(&parms.andvals, 0xff, sizeof(parms.andvals));

        parms.andvals[cr] = ~(1L << bit);

        on_each_cpu(smp_ctl_bit_callback, &parms, 0, 1);

}

EXPORT_SYMBOL(smp_ctl_clear_bit);

#if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_ZFCPDUMP_MODULE)

/*

 * zfcpdump_prefix_array holds prefix registers for the following scenario:

 * 64 bit zfcpdump kernel and 31 bit kernel which is to be dumped. We have to

 * save its prefix registers, since they get lost, when switching from 31 bit

 * to 64 bit.

 */

unsigned int zfcpdump_prefix_array[NR_CPUS + 1] \

        __attribute__((__section__(".data")));

static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)

{

        if (ipl_info.type != IPL_TYPE_FCP_DUMP)

                return;

        if (cpu >= NR_CPUS) {

                printk(KERN_WARNING "Registers for cpu %i not saved since dump "

                       "kernel was compiled with NR_CPUS=%i\n", cpu, NR_CPUS);

                return;

        }

        zfcpdump_save_areas[cpu] = alloc_bootmem(sizeof(union save_area));

        __cpu_logical_map[1] = (__u16) phy_cpu;

        while (signal_processor(1, sigp_stop_and_store_status) == sigp_busy)

                cpu_relax();

        memcpy(zfcpdump_save_areas[cpu],

               (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,

               SAVE_AREA_SIZE);

#ifdef CONFIG_64BIT

        /* copy original prefix register */

        zfcpdump_save_areas[cpu]->s390x.pref_reg = zfcpdump_prefix_array[cpu];

#endif

}

union save_area *zfcpdump_save_areas[NR_CPUS + 1];

EXPORT_SYMBOL_GPL(zfcpdump_save_areas);

#else

static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }

#endif /* CONFIG_ZFCPDUMP || CONFIG_ZFCPDUMP_MODULE */

/*

 * Lets check how many CPUs we have.

 */

static unsigned int __init smp_count_cpus(void)

{

        unsigned int cpu, num_cpus;

        __u16 boot_cpu_addr;

        /*

         * cpu 0 is the boot cpu. See smp_prepare_boot_cpu.

         */

        boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;

        current_thread_info()->cpu = 0;

        num_cpus = 1;

        for (cpu = 0; cpu <= 65535; cpu++) {

                if ((__u16) cpu == boot_cpu_addr)

                        continue;

                __cpu_logical_map[1] = (__u16) cpu;

                if (signal_processor(1, sigp_sense) == sigp_not_operational)

                        continue;

                smp_get_save_area(num_cpus, cpu);

                num_cpus++;

        }

        printk("Detected %d CPU's\n", (int) num_cpus);

        printk("Boot cpu address %2X\n", boot_cpu_addr);

        return num_cpus;

}

/*

 *      Activate a secondary processor.

 */

int __cpuinit start_secondary(void *cpuvoid)

{

        /* Setup the cpu */

        cpu_init();

        preempt_disable();

        /* Enable TOD clock interrupts on the secondary cpu. */

        init_cpu_timer();

#ifdef CONFIG_VIRT_TIMER

        /* Enable cpu timer interrupts on the secondary cpu. */

        init_cpu_vtimer();

#endif

        /* Enable pfault pseudo page faults on this cpu. */

        pfault_init();

        /* Mark this cpu as online */

        cpu_set(smp_processor_id(), cpu_online_map);

        /* Switch on interrupts */

        local_irq_enable();

        /* Print info about this processor */

        print_cpu_info(&S390_lowcore.cpu_data);

        /* cpu_idle will call schedule for us */

        cpu_idle();

        return 0;

}

DEFINE_PER_CPU(struct s390_idle_data, s390_idle);

static void __init smp_create_idle(unsigned int cpu)

{

        struct task_struct *p;

        /*

         *  don't care about the psw and regs settings since we'll never

         *  reschedule the forked task.

         */

        p = fork_idle(cpu);

        if (IS_ERR(p))

                panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));

        current_set[cpu] = p;

        spin_lock_init(&(&per_cpu(s390_idle, cpu))->lock);

}

static int cpu_stopped(int cpu)

{

        __u32 status;

        /* Check for stopped state */

        if (signal_processor_ps(&status, 0, cpu, sigp_sense) ==

            sigp_status_stored) {

                if (status & 0x40)

                        return 1;

        }

        return 0;

}

/* Upping and downing of CPUs */

int __cpu_up(unsigned int cpu)

{

        struct task_struct *idle;

        struct _lowcore *cpu_lowcore;

        struct stack_frame *sf;

        sigp_ccode ccode;

        int curr_cpu;

        for (curr_cpu = 0; curr_cpu <= 65535; curr_cpu++) {

                __cpu_logical_map[cpu] = (__u16) curr_cpu;

                if (cpu_stopped(cpu))

                        break;

        }

        if (!cpu_stopped(cpu))

                return -ENODEV;

        ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),

                                   cpu, sigp_set_prefix);

        if (ccode) {

                printk("sigp_set_prefix failed for cpu %d "

                       "with condition code %d\n",

                       (int) cpu, (int) ccode);

                return -EIO;

        }

        idle = current_set[cpu];

        cpu_lowcore = lowcore_ptr[cpu];

        cpu_lowcore->kernel_stack = (unsigned long)

                task_stack_page(idle) + THREAD_SIZE;

        sf = (struct stack_frame *) (cpu_lowcore->kernel_stack

                                     - sizeof(struct pt_regs)

                                     - sizeof(struct stack_frame));

        memset(sf, 0, sizeof(struct stack_frame));

        sf->gprs[9] = (unsigned long) sf;

        cpu_lowcore->save_area[15] = (unsigned long) sf;

        __ctl_store(cpu_lowcore->cregs_save_area[0], 0, 15);

        asm volatile(

                "       stam    0,15,0(%0)"

                : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");

        cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];

        cpu_lowcore->current_task = (unsigned long) idle;

        cpu_lowcore->cpu_data.cpu_nr = cpu;

        eieio();

        while (signal_processor(cpu, sigp_restart) == sigp_busy)

                udelay(10);

        while (!cpu_online(cpu))

                cpu_relax();

        return 0;

}

static unsigned int __initdata additional_cpus;

static unsigned int __initdata possible_cpus;

void __init smp_setup_cpu_possible_map(void)

{

        unsigned int phy_cpus, pos_cpus, cpu;

        phy_cpus = smp_count_cpus();

        pos_cpus = min(phy_cpus + additional_cpus, (unsigned int) NR_CPUS);

        if (possible_cpus)

                pos_cpus = min(possible_cpus, (unsigned int) NR_CPUS);

        for (cpu = 0; cpu < pos_cpus; cpu++)

                cpu_set(cpu, cpu_possible_map);

        phy_cpus = min(phy_cpus, pos_cpus);

        for (cpu = 0; cpu < phy_cpus; cpu++)

                cpu_set(cpu, cpu_present_map);

}

#ifdef CONFIG_HOTPLUG_CPU

static int __init setup_additional_cpus(char *s)

{

        additional_cpus = simple_strtoul(s, NULL, 0);

        return 0;

}

early_param("additional_cpus", setup_additional_cpus);

static int __init setup_possible_cpus(char *s)

{

        possible_cpus = simple_strtoul(s, NULL, 0);

        return 0;

}

early_param("possible_cpus", setup_possible_cpus);

int __cpu_disable(void)

{

        struct ec_creg_mask_parms cr_parms;

        int cpu = smp_processor_id();

        cpu_clear(cpu, cpu_online_map);

        /* Disable pfault pseudo page faults on this cpu. */

        pfault_fini();

        memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));

        memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));

        /* disable all external interrupts */

        cr_parms.orvals[0] = 0;

        cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |

                                1 << 11 | 1 << 10 | 1 <<  6 | 1 <<  4);

        /* disable all I/O interrupts */

        cr_parms.orvals[6] = 0;

        cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |

                                1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);

        /* disable most machine checks */

        cr_parms.orvals[14] = 0;

        cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |

                                 1 << 25 | 1 << 24);

        smp_ctl_bit_callback(&cr_parms);

        return 0;

}

void __cpu_die(unsigned int cpu)

{

        /* Wait until target cpu is down */

        while (!smp_cpu_not_running(cpu))

                cpu_relax();

        printk("Processor %d spun down\n", cpu);

}

void cpu_die(void)

{

        idle_task_exit();

        signal_processor(smp_processor_id(), sigp_stop);

        BUG();

        for (;;);

}

#endif /* CONFIG_HOTPLUG_CPU */

/*

 *      Cycle through the processors and setup structures.

 */

void __init smp_prepare_cpus(unsigned int max_cpus)

{

        unsigned long stack;

        unsigned int cpu;

        int i;

        /* request the 0x1201 emergency signal external interrupt */

        if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)

                panic("Couldn't request external interrupt 0x1201");

        memset(lowcore_ptr, 0, sizeof(lowcore_ptr));

        /*

         *  Initialize prefix pages and stacks for all possible cpus

         */

        print_cpu_info(&S390_lowcore.cpu_data);

        for_each_possible_cpu(i) {

                lowcore_ptr[i] = (struct _lowcore *)

                        __get_free_pages(GFP_KERNEL | GFP_DMA,

                                         sizeof(void*) == 8 ? 1 : 0);

                stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);

                if (!lowcore_ptr[i] || !stack)

                        panic("smp_boot_cpus failed to allocate memory\n");

                *(lowcore_ptr[i]) = S390_lowcore;

                lowcore_ptr[i]->async_stack = stack + ASYNC_SIZE;

                stack = __get_free_pages(GFP_KERNEL, 0);

                if (!stack)

                        panic("smp_boot_cpus failed to allocate memory\n");

                lowcore_ptr[i]->panic_stack = stack + PAGE_SIZE;

#ifndef CONFIG_64BIT

                if (MACHINE_HAS_IEEE) {

                        lowcore_ptr[i]->extended_save_area_addr =

                                (__u32) __get_free_pages(GFP_KERNEL, 0);

                        if (!lowcore_ptr[i]->extended_save_area_addr)

                                panic("smp_boot_cpus failed to "

                                      "allocate memory\n");