linux/arch/blackfin/mach-common/smp.c
Steven Miao a2eff9dd8b blackfin: smp: fix msg queue overflow issue
disable preemption when icache flush and use wait mode cross call, hold the msg
queue lock while handle cross function call to avoid overflow

Signed-off-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
2012-01-09 10:26:15 +08:00

544 lines
12 KiB
C

/*
* IPI management based on arch/arm/kernel/smp.c (Copyright 2002 ARM Limited)
*
* Copyright 2007-2009 Analog Devices Inc.
* Philippe Gerum <rpm@xenomai.org>
*
* Licensed under the GPL-2.
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/cache.h>
#include <linux/clockchips.h>
#include <linux/profile.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/seq_file.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <asm/cacheflush.h>
#include <asm/irq_handler.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/cpu.h>
#include <asm/time.h>
#include <linux/err.h>
/*
* Anomaly notes:
* 05000120 - we always define corelock as 32-bit integer in L2
*/
struct corelock_slot corelock __attribute__ ((__section__(".l2.bss")));
#ifdef CONFIG_ICACHE_FLUSH_L1
unsigned long blackfin_iflush_l1_entry[NR_CPUS];
#endif
struct blackfin_initial_pda __cpuinitdata initial_pda_coreb;
#define BFIN_IPI_TIMER 0
#define BFIN_IPI_RESCHEDULE 1
#define BFIN_IPI_CALL_FUNC 2
#define BFIN_IPI_CPU_STOP 3
struct blackfin_flush_data {
unsigned long start;
unsigned long end;
};
void *secondary_stack;
struct smp_call_struct {
void (*func)(void *info);
void *info;
int wait;
cpumask_t *waitmask;
};
static struct blackfin_flush_data smp_flush_data;
static DEFINE_SPINLOCK(stop_lock);
struct ipi_message {
unsigned long type;
struct smp_call_struct call_struct;
};
/* A magic number - stress test shows this is safe for common cases */
#define BFIN_IPI_MSGQ_LEN 5
/* Simple FIFO buffer, overflow leads to panic */
struct ipi_message_queue {
spinlock_t lock;
unsigned long count;
unsigned long head; /* head of the queue */
struct ipi_message ipi_message[BFIN_IPI_MSGQ_LEN];
};
static DEFINE_PER_CPU(struct ipi_message_queue, ipi_msg_queue);
static void ipi_cpu_stop(unsigned int cpu)
{
spin_lock(&stop_lock);
printk(KERN_CRIT "CPU%u: stopping\n", cpu);
dump_stack();
spin_unlock(&stop_lock);
set_cpu_online(cpu, false);
local_irq_disable();
while (1)
SSYNC();
}
static void ipi_flush_icache(void *info)
{
struct blackfin_flush_data *fdata = info;
/* Invalidate the memory holding the bounds of the flushed region. */
blackfin_dcache_invalidate_range((unsigned long)fdata,
(unsigned long)fdata + sizeof(*fdata));
/* Make sure all write buffers in the data side of the core
* are flushed before trying to invalidate the icache. This
* needs to be after the data flush and before the icache
* flush so that the SSYNC does the right thing in preventing
* the instruction prefetcher from hitting things in cached
* memory at the wrong time -- it runs much further ahead than
* the pipeline.
*/
SSYNC();
/* ipi_flaush_icache is invoked by generic flush_icache_range,
* so call blackfin arch icache flush directly here.
*/
blackfin_icache_flush_range(fdata->start, fdata->end);
}
static void ipi_call_function(unsigned int cpu, struct ipi_message *msg)
{
int wait;
void (*func)(void *info);
void *info;
func = msg->call_struct.func;
info = msg->call_struct.info;
wait = msg->call_struct.wait;
func(info);
if (wait) {
#ifdef __ARCH_SYNC_CORE_DCACHE
/*
* 'wait' usually means synchronization between CPUs.
* Invalidate D cache in case shared data was changed
* by func() to ensure cache coherence.
*/
resync_core_dcache();
#endif
cpumask_clear_cpu(cpu, msg->call_struct.waitmask);
}
}
/* Use IRQ_SUPPLE_0 to request reschedule.
* When returning from interrupt to user space,
* there is chance to reschedule */
static irqreturn_t ipi_handler_int0(int irq, void *dev_instance)
{
unsigned int cpu = smp_processor_id();
platform_clear_ipi(cpu, IRQ_SUPPLE_0);
return IRQ_HANDLED;
}
DECLARE_PER_CPU(struct clock_event_device, coretmr_events);
void ipi_timer(void)
{
int cpu = smp_processor_id();
struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
evt->event_handler(evt);
}
static irqreturn_t ipi_handler_int1(int irq, void *dev_instance)
{
struct ipi_message *msg;
struct ipi_message_queue *msg_queue;
unsigned int cpu = smp_processor_id();
unsigned long flags;
platform_clear_ipi(cpu, IRQ_SUPPLE_1);
msg_queue = &__get_cpu_var(ipi_msg_queue);
spin_lock_irqsave(&msg_queue->lock, flags);
while (msg_queue->count) {
msg = &msg_queue->ipi_message[msg_queue->head];
switch (msg->type) {
case BFIN_IPI_TIMER:
ipi_timer();
break;
case BFIN_IPI_RESCHEDULE:
scheduler_ipi();
break;
case BFIN_IPI_CALL_FUNC:
ipi_call_function(cpu, msg);
break;
case BFIN_IPI_CPU_STOP:
ipi_cpu_stop(cpu);
break;
default:
printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%lx\n",
cpu, msg->type);
break;
}
msg_queue->head++;
msg_queue->head %= BFIN_IPI_MSGQ_LEN;
msg_queue->count--;
}
spin_unlock_irqrestore(&msg_queue->lock, flags);
return IRQ_HANDLED;
}
static void ipi_queue_init(void)
{
unsigned int cpu;
struct ipi_message_queue *msg_queue;
for_each_possible_cpu(cpu) {
msg_queue = &per_cpu(ipi_msg_queue, cpu);
spin_lock_init(&msg_queue->lock);
msg_queue->count = 0;
msg_queue->head = 0;
}
}
static inline void smp_send_message(cpumask_t callmap, unsigned long type,
void (*func) (void *info), void *info, int wait)
{
unsigned int cpu;
struct ipi_message_queue *msg_queue;
struct ipi_message *msg;
unsigned long flags, next_msg;
cpumask_t waitmask; /* waitmask is shared by all cpus */
cpumask_copy(&waitmask, &callmap);
for_each_cpu(cpu, &callmap) {
msg_queue = &per_cpu(ipi_msg_queue, cpu);
spin_lock_irqsave(&msg_queue->lock, flags);
if (msg_queue->count < BFIN_IPI_MSGQ_LEN) {
next_msg = (msg_queue->head + msg_queue->count)
% BFIN_IPI_MSGQ_LEN;
msg = &msg_queue->ipi_message[next_msg];
msg->type = type;
if (type == BFIN_IPI_CALL_FUNC) {
msg->call_struct.func = func;
msg->call_struct.info = info;
msg->call_struct.wait = wait;
msg->call_struct.waitmask = &waitmask;
}
msg_queue->count++;
} else
panic("IPI message queue overflow\n");
spin_unlock_irqrestore(&msg_queue->lock, flags);
platform_send_ipi_cpu(cpu, IRQ_SUPPLE_1);
}
if (wait) {
while (!cpumask_empty(&waitmask))
blackfin_dcache_invalidate_range(
(unsigned long)(&waitmask),
(unsigned long)(&waitmask));
#ifdef __ARCH_SYNC_CORE_DCACHE
/*
* Invalidate D cache in case shared data was changed by
* other processors to ensure cache coherence.
*/
resync_core_dcache();
#endif
}
}
int smp_call_function(void (*func)(void *info), void *info, int wait)
{
cpumask_t callmap;
preempt_disable();
cpumask_copy(&callmap, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &callmap);
if (!cpumask_empty(&callmap))
smp_send_message(callmap, BFIN_IPI_CALL_FUNC, func, info, wait);
preempt_enable();
return 0;
}
EXPORT_SYMBOL_GPL(smp_call_function);
int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
int wait)
{
unsigned int cpu = cpuid;
cpumask_t callmap;
if (cpu_is_offline(cpu))
return 0;
cpumask_clear(&callmap);
cpumask_set_cpu(cpu, &callmap);
smp_send_message(callmap, BFIN_IPI_CALL_FUNC, func, info, wait);
return 0;
}
EXPORT_SYMBOL_GPL(smp_call_function_single);
void smp_send_reschedule(int cpu)
{
cpumask_t callmap;
/* simply trigger an ipi */
cpumask_clear(&callmap);
cpumask_set_cpu(cpu, &callmap);
smp_send_message(callmap, BFIN_IPI_RESCHEDULE, NULL, NULL, 0);
return;
}
void smp_send_msg(const struct cpumask *mask, unsigned long type)
{
smp_send_message(*mask, type, NULL, NULL, 0);
}
void smp_timer_broadcast(const struct cpumask *mask)
{
smp_send_msg(mask, BFIN_IPI_TIMER);
}
void smp_send_stop(void)
{
cpumask_t callmap;
preempt_disable();
cpumask_copy(&callmap, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &callmap);
if (!cpumask_empty(&callmap))
smp_send_message(callmap, BFIN_IPI_CPU_STOP, NULL, NULL, 0);
preempt_enable();
return;
}
int __cpuinit __cpu_up(unsigned int cpu)
{
int ret;
struct blackfin_cpudata *ci = &per_cpu(cpu_data, cpu);
struct task_struct *idle = ci->idle;
if (idle) {
free_task(idle);
idle = NULL;
}
if (!idle) {
idle = fork_idle(cpu);
if (IS_ERR(idle)) {
printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
return PTR_ERR(idle);
}
ci->idle = idle;
} else {
init_idle(idle, cpu);
}
secondary_stack = task_stack_page(idle) + THREAD_SIZE;
ret = platform_boot_secondary(cpu, idle);
secondary_stack = NULL;
return ret;
}
static void __cpuinit setup_secondary(unsigned int cpu)
{
unsigned long ilat;
bfin_write_IMASK(0);
CSYNC();
ilat = bfin_read_ILAT();
CSYNC();
bfin_write_ILAT(ilat);
CSYNC();
/* Enable interrupt levels IVG7-15. IARs have been already
* programmed by the boot CPU. */
bfin_irq_flags |= IMASK_IVG15 |
IMASK_IVG14 | IMASK_IVG13 | IMASK_IVG12 | IMASK_IVG11 |
IMASK_IVG10 | IMASK_IVG9 | IMASK_IVG8 | IMASK_IVG7 | IMASK_IVGHW;
}
void __cpuinit secondary_start_kernel(void)
{
unsigned int cpu = smp_processor_id();
struct mm_struct *mm = &init_mm;
if (_bfin_swrst & SWRST_DBL_FAULT_B) {
printk(KERN_EMERG "CoreB Recovering from DOUBLE FAULT event\n");
#ifdef CONFIG_DEBUG_DOUBLEFAULT
printk(KERN_EMERG " While handling exception (EXCAUSE = %#x) at %pF\n",
initial_pda_coreb.seqstat_doublefault & SEQSTAT_EXCAUSE,
initial_pda_coreb.retx_doublefault);
printk(KERN_NOTICE " DCPLB_FAULT_ADDR: %pF\n",
initial_pda_coreb.dcplb_doublefault_addr);
printk(KERN_NOTICE " ICPLB_FAULT_ADDR: %pF\n",
initial_pda_coreb.icplb_doublefault_addr);
#endif
printk(KERN_NOTICE " The instruction at %pF caused a double exception\n",
initial_pda_coreb.retx);
}
/*
* We want the D-cache to be enabled early, in case the atomic
* support code emulates cache coherence (see
* __ARCH_SYNC_CORE_DCACHE).
*/
init_exception_vectors();
local_irq_disable();
/* Attach the new idle task to the global mm. */
atomic_inc(&mm->mm_users);
atomic_inc(&mm->mm_count);
current->active_mm = mm;
preempt_disable();
setup_secondary(cpu);
platform_secondary_init(cpu);
/* setup local core timer */
bfin_local_timer_setup();
local_irq_enable();
bfin_setup_caches(cpu);
notify_cpu_starting(cpu);
/*
* Calibrate loops per jiffy value.
* IRQs need to be enabled here - D-cache can be invalidated
* in timer irq handler, so core B can read correct jiffies.
*/
calibrate_delay();
cpu_idle();
}
void __init smp_prepare_boot_cpu(void)
{
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
platform_prepare_cpus(max_cpus);
ipi_queue_init();
platform_request_ipi(IRQ_SUPPLE_0, ipi_handler_int0);
platform_request_ipi(IRQ_SUPPLE_1, ipi_handler_int1);
}
void __init smp_cpus_done(unsigned int max_cpus)
{
unsigned long bogosum = 0;
unsigned int cpu;
for_each_online_cpu(cpu)
bogosum += loops_per_jiffy;
printk(KERN_INFO "SMP: Total of %d processors activated "
"(%lu.%02lu BogoMIPS).\n",
num_online_cpus(),
bogosum / (500000/HZ),
(bogosum / (5000/HZ)) % 100);
}
void smp_icache_flush_range_others(unsigned long start, unsigned long end)
{
smp_flush_data.start = start;
smp_flush_data.end = end;
preempt_disable();
if (smp_call_function(&ipi_flush_icache, &smp_flush_data, 1))
printk(KERN_WARNING "SMP: failed to run I-cache flush request on other CPUs\n");
preempt_enable();
}
EXPORT_SYMBOL_GPL(smp_icache_flush_range_others);
#ifdef __ARCH_SYNC_CORE_ICACHE
unsigned long icache_invld_count[NR_CPUS];
void resync_core_icache(void)
{
unsigned int cpu = get_cpu();
blackfin_invalidate_entire_icache();
icache_invld_count[cpu]++;
put_cpu();
}
EXPORT_SYMBOL(resync_core_icache);
#endif
#ifdef __ARCH_SYNC_CORE_DCACHE
unsigned long dcache_invld_count[NR_CPUS];
unsigned long barrier_mask __attribute__ ((__section__(".l2.bss")));
void resync_core_dcache(void)
{
unsigned int cpu = get_cpu();
blackfin_invalidate_entire_dcache();
dcache_invld_count[cpu]++;
put_cpu();
}
EXPORT_SYMBOL(resync_core_dcache);
#endif
#ifdef CONFIG_HOTPLUG_CPU
int __cpuexit __cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
if (cpu == 0)
return -EPERM;
set_cpu_online(cpu, false);
return 0;
}
static DECLARE_COMPLETION(cpu_killed);
int __cpuexit __cpu_die(unsigned int cpu)
{
return wait_for_completion_timeout(&cpu_killed, 5000);
}
void cpu_die(void)
{
complete(&cpu_killed);
atomic_dec(&init_mm.mm_users);
atomic_dec(&init_mm.mm_count);
local_irq_disable();
platform_cpu_die();
}
#endif