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/*
* arch/s390/kernel/smp.c
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
* Martin Schwidefsky (schwidefsky@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 <asm/sigp.h>
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/s390_ext.h>
#include <asm/cpcmd.h>
/* prototypes */
extern int cpu_idle(void * unused);
extern __u16 boot_cpu_addr;
extern volatile int __cpu_logical_map[];
/*
* An array with a pointer the lowcore of every CPU.
*/
static int max_cpus = NR_CPUS; /* Setup configured maximum number of CPUs to activate */
int smp_num_cpus;
struct _lowcore *lowcore_ptr[NR_CPUS];
cycles_t cacheflush_time=0;
int smp_threads_ready=0; /* Set when the idlers are all forked. */
static atomic_t smp_commenced = ATOMIC_INIT(0);
spinlock_t kernel_flag __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
unsigned long cpu_online_map;
/*
* Setup routine for controlling SMP activation
*
* Command-line option of "nosmp" or "maxcpus=0" will disable SMP
* activation entirely (the MPS table probe still happens, though).
*
* Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
* greater than 0, limits the maximum number of CPUs activated in
* SMP mode to <NUM>.
*/
static int __init nosmp(char *str)
{
max_cpus = 0;
return 1;
}
__setup("nosmp", nosmp);
static int __init maxcpus(char *str)
{
get_option(&str, &max_cpus);
return 1;
}
__setup("maxcpus=", maxcpus);
/*
* Reboot, halt and power_off routines for SMP.
*/
extern char vmhalt_cmd[];
extern char vmpoff_cmd[];
extern void reipl(unsigned long devno);
static sigp_ccode smp_ext_bitcall(int, ec_bit_sig);
static void smp_ext_bitcall_others(ec_bit_sig);
/*
* Structure and data for smp_call_function(). This is designed to minimise
* static memory requirements. It also looks cleaner.
*/
static spinlock_t call_lock = SPIN_LOCK_UNLOCKED;
struct call_data_struct {
void (*func) (void *info);
void *info;
atomic_t started;
atomic_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;
atomic_inc(&call_data->started);
(*func)(info);
if (wait)
atomic_inc(&call_data->finished);
}
/*
* this function sends a 'generic call function' IPI to all other CPUs
* in the system.
*/
int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
int wait)
/*
* [SUMMARY] Run a function on all other CPUs.
* <func> The function to run. This must be fast and non-blocking.
* <info> An arbitrary pointer to pass to the function.
* <nonatomic> currently unused.
* <wait> If true, wait (atomically) until function has completed on other CPUs.
* [RETURNS] 0 on success, else a negative status code. Does not return until
* remote CPUs are nearly ready to execute <<func>> or are or have executed.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler, you may call it from a bottom half handler.
*/
{
struct call_data_struct data;
int cpus = smp_num_cpus-1;
if (!cpus || !atomic_read(&smp_commenced))
return 0;
data.func = func;
data.info = info;
atomic_set(&data.started, 0);
data.wait = wait;
if (wait)
atomic_set(&data.finished, 0);
spin_lock_bh(&call_lock);
call_data = &data;
/* Send a message to all other CPUs and wait for them to respond */
smp_ext_bitcall_others(ec_call_function);
/* Wait for response */
while (atomic_read(&data.started) != cpus)
barrier();
if (wait)
while (atomic_read(&data.finished) != cpus)
barrier();
spin_unlock_bh(&call_lock);
return 0;
}
/*
* Various special callbacks
*/
void do_machine_restart(void)
{
smp_send_stop();
reipl(S390_lowcore.ipl_device);
}
void machine_restart(char * __unused)
{
if (smp_processor_id() != 0) {
smp_ext_bitcall(0, ec_restart);
for (;;);
} else
do_machine_restart();
}
void do_machine_halt(void)
{
smp_send_stop();
if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
cpcmd(vmhalt_cmd, NULL, 0);
signal_processor(smp_processor_id(), sigp_stop_and_store_status);
}
void machine_halt(void)
{
if (smp_processor_id() != 0) {
smp_ext_bitcall(0, ec_halt);
for (;;);
} else
do_machine_halt();
}
void do_machine_power_off(void)
{
smp_send_stop();
if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
cpcmd(vmpoff_cmd, NULL, 0);
signal_processor(smp_processor_id(), sigp_stop_and_store_status);
}
void machine_power_off(void)
{
if (smp_processor_id() != 0) {
smp_ext_bitcall(0, ec_power_off);
for (;;);
} else
do_machine_power_off();
}
/*
* This is the main routine where commands issued by other
* cpus are handled.
*/
void do_ext_call_interrupt(struct pt_regs *regs, __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.
* For the ec_restart, ec_halt and ec_power_off we call the
* appropriate routine.
*/
bits = xchg(&S390_lowcore.ext_call_fast, 0);
if (test_bit(ec_restart, &bits))
do_machine_restart();
if (test_bit(ec_halt, &bits))
do_machine_halt();
if (test_bit(ec_power_off, &bits))
do_machine_power_off();
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 sigp_ccode smp_ext_bitcall(int cpu, ec_bit_sig sig)
{
sigp_ccode ccode;
/*
* Set signaling bit in lowcore of target cpu and kick it
*/
set_bit(sig, &(get_cpu_lowcore(cpu).ext_call_fast));
ccode = signal_processor(cpu, sigp_external_call);
return ccode;
}
/*
* Send an external call sigp to every other cpu in the system and
* return without waiting for its completion.
*/
static void smp_ext_bitcall_others(ec_bit_sig sig)
{
sigp_ccode ccode;
int i;
for (i = 0; i < smp_num_cpus; i++) {
if (smp_processor_id() == i)
continue;
/*
* Set signaling bit in lowcore of target cpu and kick it
*/
set_bit(sig, &(get_cpu_lowcore(i).ext_call_fast));
ccode = signal_processor(i, sigp_external_call);
}
}
/*
* this function sends a 'stop' sigp to all other CPUs in the system.
* it goes straight through.
*/
void smp_send_stop(void)
{
int i;
u32 dummy;
unsigned long low_core_addr;
/* write magic number to zero page (absolute 0) */
get_cpu_lowcore(smp_processor_id()).panic_magic = __PANIC_MAGIC;
/* stop all processors */
for (i = 0; i < smp_num_cpus; i++) {
if (smp_processor_id() != i) {
int ccode;
do {
ccode = signal_processor_ps(
&dummy,
0,
i,
sigp_stop);
} while(ccode == sigp_busy);
}
}
/* store status of all processors in their lowcores (real 0) */
for (i = 0; i < smp_num_cpus; i++) {
if (smp_processor_id() != i) {
int ccode;
low_core_addr = (unsigned long)&get_cpu_lowcore(i);
do {
ccode = signal_processor_ps(
&dummy,
low_core_addr,
i,
sigp_store_status_at_address);
} while(ccode == sigp_busy);
}
}
}
/*
* 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
*/
typedef struct
{
__u16 start_ctl;
__u16 end_ctl;
__u64 orvals[16];
__u64 andvals[16];
} ec_creg_mask_parms;
/*
* callback for setting/clearing control bits
*/
void smp_ctl_bit_callback(void *info) {
ec_creg_mask_parms *pp;
u64 cregs[16];
int i;
pp = (ec_creg_mask_parms *) info;
asm volatile (" bras 1,0f\n"
" stctg 0,0,0(%0)\n"
"0: ex %1,0(1)\n"
: : "a" (cregs+pp->start_ctl),
"a" ((pp->start_ctl<<4) + pp->end_ctl)
: "memory", "1" );
for (i = pp->start_ctl; i <= pp->end_ctl; i++)
cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
asm volatile (" bras 1,0f\n"
" lctlg 0,0,0(%0)\n"
"0: ex %1,0(1)\n"
: : "a" (cregs+pp->start_ctl),
"a" ((pp->start_ctl<<4) + pp->end_ctl)
: "memory", "1" );
}
/*
* Set a bit in a control register of all cpus
*/
void smp_ctl_set_bit(int cr, int bit) {
ec_creg_mask_parms parms;
if (atomic_read(&smp_commenced) != 0) {
parms.start_ctl = cr;
parms.end_ctl = cr;
parms.orvals[cr] = 1 << bit;
parms.andvals[cr] = -1L;
smp_call_function(smp_ctl_bit_callback, &parms, 0, 1);
}
__ctl_set_bit(cr, bit);
}
/*
* Clear a bit in a control register of all cpus
*/
void smp_ctl_clear_bit(int cr, int bit) {
ec_creg_mask_parms parms;
if (atomic_read(&smp_commenced) != 0) {
parms.start_ctl = cr;
parms.end_ctl = cr;
parms.orvals[cr] = 0;
parms.andvals[cr] = ~(1L << bit);
smp_call_function(smp_ctl_bit_callback, &parms, 0, 1);
}
__ctl_clear_bit(cr, bit);
}
/*
* Lets check how many CPUs we have.
*/
void smp_count_cpus(void)
{
int curr_cpu;
current->processor = 0;
smp_num_cpus = 1;
for (curr_cpu = 0;
curr_cpu <= 65535 && smp_num_cpus < max_cpus; curr_cpu++) {
if ((__u16) curr_cpu == boot_cpu_addr)
continue;
__cpu_logical_map[smp_num_cpus] = (__u16) curr_cpu;
if (signal_processor(smp_num_cpus, sigp_sense) ==
sigp_not_operational)
continue;
smp_num_cpus++;
}
printk("Detected %d CPU's\n",(int) smp_num_cpus);
printk("Boot cpu address %2X\n", boot_cpu_addr);
}
/*
* Activate a secondary processor.
*/
extern void init_cpu_timer(void);
extern int pfault_init(void);
int __init start_secondary(void *cpuvoid)
{
/* Setup the cpu */
cpu_init();
/* Print info about this processor */
print_cpu_info(&safe_get_cpu_lowcore(smp_processor_id()).cpu_data);
/* Wait for completion of smp startup */
while (!atomic_read(&smp_commenced))
/* nothing */ ;
/* init per CPU timer */
init_cpu_timer();
#ifdef CONFIG_PFAULT
/* Enable pfault pseudo page faults on this cpu. */
pfault_init();
#endif
/* cpu_idle will call schedule for us */
return cpu_idle(NULL);
}
/*
* The restart interrupt handler jumps to start_secondary directly
* without the detour over initialize_secondary. We defined it here
* so that the linker doesn't complain.
*/
void __init initialize_secondary(void)
{
}
static int __init fork_by_hand(void)
{
struct pt_regs regs;
/* don't care about the psw and regs settings since we'll never
reschedule the forked task. */
memset(®s,0,sizeof(struct pt_regs));
return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
}
static void __init do_boot_cpu(int cpu)
{
struct task_struct *idle;
struct _lowcore *cpu_lowcore;
/* We can't use kernel_thread since we must _avoid_ to reschedule
the child. */
if (fork_by_hand() < 0)
panic("failed fork for CPU %d", cpu);
/*
* We remove it from the pidhash and the runqueue
* once we got the process:
*/
idle = init_task.prev_task;
if (!idle)
panic("No idle process for CPU %d",cpu);
idle->processor = cpu;
idle->cpus_runnable = 1 << cpu; /* we schedule the first task manually */
del_from_runqueue(idle);
unhash_process(idle);
init_tasks[cpu] = idle;
cpu_lowcore=&get_cpu_lowcore(cpu);
cpu_lowcore->save_area[15] = idle->thread.ksp;
cpu_lowcore->kernel_stack = (__u64) idle + 16384;
__asm__ __volatile__("la 1,%0\n\t"
"stctg 0,15,0(1)\n\t"
"la 1,%1\n\t"
"stam 0,15,0(1)"
: "=m" (cpu_lowcore->cregs_save_area[0]),
"=m" (cpu_lowcore->access_regs_save_area[0])
: : "1", "memory");
eieio();
signal_processor(cpu,sigp_restart);
/* Mark this cpu as online. */
set_bit(cpu, &cpu_online_map);
}
/*
* Architecture specific routine called by the kernel just before init is
* fired off. This allows the BP to have everything in order [we hope].
* At the end of this all the APs will hit the system scheduling and off
* we go. Each AP will load the system gdt's and jump through the kernel
* init into idle(). At this point the scheduler will one day take over
* and give them jobs to do. smp_callin is a standard routine
* we use to track CPUs as they power up.
*/
void __init smp_commence(void)
{
/*
* Lets the callins below out of their loop.
*/
atomic_set(&smp_commenced,1);
}
/*
* Cycle through the processors sending restart sigps to boot each.
*/
void __init smp_boot_cpus(void)
{
struct _lowcore *curr_lowcore;
unsigned long async_stack;
sigp_ccode ccode;
int i;
/* request the 0x1202 external interrupt */
if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
panic("Couldn't request external interrupt 0x1202");
smp_count_cpus();
memset(lowcore_ptr,0,sizeof(lowcore_ptr));
/*
* Initialize the logical to physical CPU number mapping
*/
print_cpu_info(&safe_get_cpu_lowcore(0).cpu_data);
for(i = 0; i < smp_num_cpus; i++)
{
curr_lowcore = (struct _lowcore *)
__get_free_pages(GFP_KERNEL|GFP_DMA, 1);
if (curr_lowcore == NULL) {
printk("smp_boot_cpus failed to allocate prefix memory\n");
break;
}
async_stack = __get_free_pages(GFP_KERNEL,2);
if (async_stack == 0) {
printk("smp_boot_cpus failed to allocate asyncronous"
" interrupt stack\n");
free_page((unsigned long) curr_lowcore);
break;
}
lowcore_ptr[i] = curr_lowcore;
memcpy(curr_lowcore, &S390_lowcore, sizeof(struct _lowcore));
curr_lowcore->async_stack = async_stack + (4 * PAGE_SIZE);
/*
* Most of the parameters are set up when the cpu is
* started up.
*/
if (smp_processor_id() == i)
set_prefix((u32)(u64)curr_lowcore);
else {
ccode = signal_processor_p((u64)(curr_lowcore),
i, sigp_set_prefix);
if(ccode) {
/* if this gets troublesome I'll have to do
* something about it. */
printk("ccode %d for cpu %d returned when "
"setting prefix in smp_boot_cpus not good.\n",
(int) ccode, (int) i);
}
else
do_boot_cpu(i);
}
}
}
/*
* 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;
}
EXPORT_SYMBOL(lowcore_ptr);
EXPORT_SYMBOL(kernel_flag);
EXPORT_SYMBOL(smp_ctl_set_bit);
EXPORT_SYMBOL(smp_ctl_clear_bit);
EXPORT_SYMBOL(smp_num_cpus);
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