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linux/arch/s390/kernel/smp.c

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/*
* arch/s390/kernel/smp.c
*
* Copyright (C) IBM Corp. 1999,2006
* 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/spinlock.h>
#include <linux/kernel_stat.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/timex.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>
extern volatile int __cpu_logical_map[];
/*
* An array with a pointer the lowcore of every CPU.
*/
struct _lowcore *lowcore_ptr[NR_CPUS];
cpumask_t cpu_online_map = CPU_MASK_NONE;
cpumask_t cpu_possible_map = CPU_MASK_NONE;
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_bh(&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_bh(&call_lock);
out:
local_irq_disable();
if (local)
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 or from a
* hardware interrupt handler. You may call it 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_on:
* @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
* @cpu: the CPU where func should run
*
* Run a function on one processor.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler. You may call it from a bottom half.
*/
int smp_call_function_on(void (*func) (void *info), void *info, int nonatomic,
int wait, int cpu)
{
cpumask_t map = CPU_MASK_NONE;
preempt_disable();
cpu_set(cpu, map);
__smp_call_function_map(func, info, nonatomic, wait, map);
preempt_enable();
return 0;
}
EXPORT_SYMBOL(smp_call_function_on);
static void do_send_stop(void)
{
int cpu, rc;
/* 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);
}
}
static void do_store_status(void)
{
int cpu, rc;
/* store status of all processors in their lowcores (real 0) */
for_each_online_cpu(cpu) {
if (cpu == smp_processor_id())
continue;
do {
rc = signal_processor_p(
(__u32)(unsigned long) lowcore_ptr[cpu], cpu,
sigp_store_status_at_address);
} while(rc == sigp_busy);
}
}
static void do_wait_for_stop(void)
{
int cpu;
/* Wait for all other cpus to enter stopped state */
for_each_online_cpu(cpu) {
if (cpu == smp_processor_id())
continue;
while(!smp_cpu_not_running(cpu))
cpu_relax();
}
}
/*
* this function sends a 'stop' sigp to all other CPUs in the system.
* it goes straight through.
*/
void smp_send_stop(void)
{
/* 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 other processors. */
do_send_stop();
/* wait until other processors are stopped */
do_wait_for_stop();
/* store status of other processors. */
do_store_status();
}
/*
* 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)
{
local_flush_tlb();
}
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);
}
/*
* 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);
}
/*
* 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;
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 __devinit 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;
}
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;
}
/* Reserving and releasing of CPUs */
static DEFINE_SPINLOCK(smp_reserve_lock);
static int smp_cpu_reserved[NR_CPUS];
int
smp_get_cpu(cpumask_t cpu_mask)
{
unsigned long flags;
int cpu;
spin_lock_irqsave(&smp_reserve_lock, flags);
/* Try to find an already reserved cpu. */
for_each_cpu_mask(cpu, cpu_mask) {
if (smp_cpu_reserved[cpu] != 0) {
smp_cpu_reserved[cpu]++;
/* Found one. */
goto out;
}
}
/* Reserve a new cpu from cpu_mask. */
for_each_cpu_mask(cpu, cpu_mask) {
if (cpu_online(cpu)) {
smp_cpu_reserved[cpu]++;
goto out;
}
}
cpu = -ENODEV;
out:
spin_unlock_irqrestore(&smp_reserve_lock, flags);
return cpu;
}
void
smp_put_cpu(int cpu)
{
unsigned long flags;
spin_lock_irqsave(&smp_reserve_lock, flags);
smp_cpu_reserved[cpu]--;
spin_unlock_irqrestore(&smp_reserve_lock, flags);
}
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)
{
unsigned long flags;
struct ec_creg_mask_parms cr_parms;
int cpu = smp_processor_id();
spin_lock_irqsave(&smp_reserve_lock, flags);
if (smp_cpu_reserved[cpu] != 0) {
spin_unlock_irqrestore(&smp_reserve_lock, flags);
return -EBUSY;
}
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);
spin_unlock_irqrestore(&smp_reserve_lock, flags);
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] == NULL || stack == 0ULL)
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 == 0ULL)
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 == 0)
panic("smp_boot_cpus failed to "
"allocate memory\n");
}
#endif
}
#ifndef CONFIG_64BIT
if (MACHINE_HAS_IEEE)
ctl_set_bit(14, 29); /* enable extended save area */
#endif
set_prefix((u32)(unsigned long) lowcore_ptr[smp_processor_id()]);
for_each_possible_cpu(cpu)
if (cpu != smp_processor_id())
smp_create_idle(cpu);
}
void __devinit smp_prepare_boot_cpu(void)
{
BUG_ON(smp_processor_id() != 0);
cpu_set(0, cpu_online_map);
S390_lowcore.percpu_offset = __per_cpu_offset[0];
current_set[0] = current;
}
void smp_cpus_done(unsigned int max_cpus)
{
cpu_present_map = cpu_possible_map;
}
/*
* the frequency of the profiling timer can be changed
* by writing a multiplier value into /proc/profile.
*
* usually you want to run this on all CPUs ;)
*/
int setup_profiling_timer(unsigned int multiplier)
{
return 0;
}
static DEFINE_PER_CPU(struct cpu, cpu_devices);
static int __init topology_init(void)
{
int cpu;
int ret;
for_each_possible_cpu(cpu) {
struct cpu *c = &per_cpu(cpu_devices, cpu);
c->hotpluggable = 1;
ret = register_cpu(c, cpu);
if (ret)
printk(KERN_WARNING "topology_init: register_cpu %d "
"failed (%d)\n", cpu, ret);
}
return 0;
}
subsys_initcall(topology_init);
EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);
EXPORT_SYMBOL(lowcore_ptr);
EXPORT_SYMBOL(smp_ctl_set_bit);
EXPORT_SYMBOL(smp_ctl_clear_bit);
EXPORT_SYMBOL(smp_get_cpu);
EXPORT_SYMBOL(smp_put_cpu);
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