linux/arch/powerpc/kernel/smp.c
Michael Ellerman 6f5e40a300 powerpc: Check cpu_thread_in_subcore() in __cpu_up()
To support split core we need to change the check in __cpu_up() that
determines if a cpu is allowed to come online.

Currently we refuse to online cpus which are not the primary thread
within their core.

On POWER8 with split core support this check needs to instead refuse to
online cpus which are not the primary thread within their *sub* core.

On POWER7 and other systems that do not support split core,
threads_per_subcore == threads_per_core and so the check is equivalent.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-28 13:35:36 +10:00

826 lines
18 KiB
C

/*
* SMP support for ppc.
*
* Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
* deal of code from the sparc and intel versions.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*
* PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/topology.h>
#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/irq.h>
#include <asm/hw_irq.h>
#include <asm/kvm_ppc.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputhreads.h>
#include <asm/cputable.h>
#include <asm/mpic.h>
#include <asm/vdso_datapage.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#endif
#include <asm/vdso.h>
#include <asm/debug.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
static DEFINE_PER_CPU(int, cpu_state) = { 0 };
#endif
struct thread_info *secondary_ti;
DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);
/* SMP operations for this machine */
struct smp_ops_t *smp_ops;
/* Can't be static due to PowerMac hackery */
volatile unsigned int cpu_callin_map[NR_CPUS];
int smt_enabled_at_boot = 1;
static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
/*
* Returns 1 if the specified cpu should be brought up during boot.
* Used to inhibit booting threads if they've been disabled or
* limited on the command line
*/
int smp_generic_cpu_bootable(unsigned int nr)
{
/* Special case - we inhibit secondary thread startup
* during boot if the user requests it.
*/
if (system_state == SYSTEM_BOOTING && cpu_has_feature(CPU_FTR_SMT)) {
if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
return 0;
if (smt_enabled_at_boot
&& cpu_thread_in_core(nr) >= smt_enabled_at_boot)
return 0;
}
return 1;
}
#ifdef CONFIG_PPC64
int smp_generic_kick_cpu(int nr)
{
BUG_ON(nr < 0 || nr >= NR_CPUS);
/*
* The processor is currently spinning, waiting for the
* cpu_start field to become non-zero After we set cpu_start,
* the processor will continue on to secondary_start
*/
if (!paca[nr].cpu_start) {
paca[nr].cpu_start = 1;
smp_mb();
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* Ok it's not there, so it might be soft-unplugged, let's
* try to bring it back
*/
generic_set_cpu_up(nr);
smp_wmb();
smp_send_reschedule(nr);
#endif /* CONFIG_HOTPLUG_CPU */
return 0;
}
#endif /* CONFIG_PPC64 */
static irqreturn_t call_function_action(int irq, void *data)
{
generic_smp_call_function_interrupt();
return IRQ_HANDLED;
}
static irqreturn_t reschedule_action(int irq, void *data)
{
scheduler_ipi();
return IRQ_HANDLED;
}
static irqreturn_t tick_broadcast_ipi_action(int irq, void *data)
{
tick_broadcast_ipi_handler();
return IRQ_HANDLED;
}
static irqreturn_t debug_ipi_action(int irq, void *data)
{
if (crash_ipi_function_ptr) {
crash_ipi_function_ptr(get_irq_regs());
return IRQ_HANDLED;
}
#ifdef CONFIG_DEBUGGER
debugger_ipi(get_irq_regs());
#endif /* CONFIG_DEBUGGER */
return IRQ_HANDLED;
}
static irq_handler_t smp_ipi_action[] = {
[PPC_MSG_CALL_FUNCTION] = call_function_action,
[PPC_MSG_RESCHEDULE] = reschedule_action,
[PPC_MSG_TICK_BROADCAST] = tick_broadcast_ipi_action,
[PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
};
const char *smp_ipi_name[] = {
[PPC_MSG_CALL_FUNCTION] = "ipi call function",
[PPC_MSG_RESCHEDULE] = "ipi reschedule",
[PPC_MSG_TICK_BROADCAST] = "ipi tick-broadcast",
[PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
};
/* optional function to request ipi, for controllers with >= 4 ipis */
int smp_request_message_ipi(int virq, int msg)
{
int err;
if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
return -EINVAL;
}
#if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
if (msg == PPC_MSG_DEBUGGER_BREAK) {
return 1;
}
#endif
err = request_irq(virq, smp_ipi_action[msg],
IRQF_PERCPU | IRQF_NO_THREAD | IRQF_NO_SUSPEND,
smp_ipi_name[msg], NULL);
WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
virq, smp_ipi_name[msg], err);
return err;
}
#ifdef CONFIG_PPC_SMP_MUXED_IPI
struct cpu_messages {
int messages; /* current messages */
unsigned long data; /* data for cause ipi */
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
void smp_muxed_ipi_set_data(int cpu, unsigned long data)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
info->data = data;
}
void smp_muxed_ipi_message_pass(int cpu, int msg)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
char *message = (char *)&info->messages;
/*
* Order previous accesses before accesses in the IPI handler.
*/
smp_mb();
message[msg] = 1;
/*
* cause_ipi functions are required to include a full barrier
* before doing whatever causes the IPI.
*/
smp_ops->cause_ipi(cpu, info->data);
}
#ifdef __BIG_ENDIAN__
#define IPI_MESSAGE(A) (1 << (24 - 8 * (A)))
#else
#define IPI_MESSAGE(A) (1 << (8 * (A)))
#endif
irqreturn_t smp_ipi_demux(void)
{
struct cpu_messages *info = &__get_cpu_var(ipi_message);
unsigned int all;
mb(); /* order any irq clear */
do {
all = xchg(&info->messages, 0);
if (all & IPI_MESSAGE(PPC_MSG_CALL_FUNCTION))
generic_smp_call_function_interrupt();
if (all & IPI_MESSAGE(PPC_MSG_RESCHEDULE))
scheduler_ipi();
if (all & IPI_MESSAGE(PPC_MSG_TICK_BROADCAST))
tick_broadcast_ipi_handler();
if (all & IPI_MESSAGE(PPC_MSG_DEBUGGER_BREAK))
debug_ipi_action(0, NULL);
} while (info->messages);
return IRQ_HANDLED;
}
#endif /* CONFIG_PPC_SMP_MUXED_IPI */
static inline void do_message_pass(int cpu, int msg)
{
if (smp_ops->message_pass)
smp_ops->message_pass(cpu, msg);
#ifdef CONFIG_PPC_SMP_MUXED_IPI
else
smp_muxed_ipi_message_pass(cpu, msg);
#endif
}
void smp_send_reschedule(int cpu)
{
if (likely(smp_ops))
do_message_pass(cpu, PPC_MSG_RESCHEDULE);
}
EXPORT_SYMBOL_GPL(smp_send_reschedule);
void arch_send_call_function_single_ipi(int cpu)
{
do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask)
do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
}
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
void tick_broadcast(const struct cpumask *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask)
do_message_pass(cpu, PPC_MSG_TICK_BROADCAST);
}
#endif
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
void smp_send_debugger_break(void)
{
int cpu;
int me = raw_smp_processor_id();
if (unlikely(!smp_ops))
return;
for_each_online_cpu(cpu)
if (cpu != me)
do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
}
#endif
#ifdef CONFIG_KEXEC
void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
{
crash_ipi_function_ptr = crash_ipi_callback;
if (crash_ipi_callback) {
mb();
smp_send_debugger_break();
}
}
#endif
static void stop_this_cpu(void *dummy)
{
/* Remove this CPU */
set_cpu_online(smp_processor_id(), false);
local_irq_disable();
while (1)
;
}
void smp_send_stop(void)
{
smp_call_function(stop_this_cpu, NULL, 0);
}
struct thread_info *current_set[NR_CPUS];
static void smp_store_cpu_info(int id)
{
per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
#ifdef CONFIG_PPC_FSL_BOOK3E
per_cpu(next_tlbcam_idx, id)
= (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
#endif
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int cpu;
DBG("smp_prepare_cpus\n");
/*
* setup_cpu may need to be called on the boot cpu. We havent
* spun any cpus up but lets be paranoid.
*/
BUG_ON(boot_cpuid != smp_processor_id());
/* Fixup boot cpu */
smp_store_cpu_info(boot_cpuid);
cpu_callin_map[boot_cpuid] = 1;
for_each_possible_cpu(cpu) {
zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
}
cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
if (smp_ops && smp_ops->probe)
smp_ops->probe();
}
void smp_prepare_boot_cpu(void)
{
BUG_ON(smp_processor_id() != boot_cpuid);
#ifdef CONFIG_PPC64
paca[boot_cpuid].__current = current;
#endif
set_numa_node(numa_cpu_lookup_table[boot_cpuid]);
current_set[boot_cpuid] = task_thread_info(current);
}
#ifdef CONFIG_HOTPLUG_CPU
int generic_cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
if (cpu == boot_cpuid)
return -EBUSY;
set_cpu_online(cpu, false);
#ifdef CONFIG_PPC64
vdso_data->processorCount--;
#endif
migrate_irqs();
return 0;
}
void generic_cpu_die(unsigned int cpu)
{
int i;
for (i = 0; i < 100; i++) {
smp_rmb();
if (per_cpu(cpu_state, cpu) == CPU_DEAD)
return;
msleep(100);
}
printk(KERN_ERR "CPU%d didn't die...\n", cpu);
}
void generic_mach_cpu_die(void)
{
unsigned int cpu;
local_irq_disable();
idle_task_exit();
cpu = smp_processor_id();
printk(KERN_DEBUG "CPU%d offline\n", cpu);
__get_cpu_var(cpu_state) = CPU_DEAD;
smp_wmb();
while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
cpu_relax();
}
void generic_set_cpu_dead(unsigned int cpu)
{
per_cpu(cpu_state, cpu) = CPU_DEAD;
}
/*
* The cpu_state should be set to CPU_UP_PREPARE in kick_cpu(), otherwise
* the cpu_state is always CPU_DEAD after calling generic_set_cpu_dead(),
* which makes the delay in generic_cpu_die() not happen.
*/
void generic_set_cpu_up(unsigned int cpu)
{
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
}
int generic_check_cpu_restart(unsigned int cpu)
{
return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
}
static bool secondaries_inhibited(void)
{
return kvm_hv_mode_active();
}
#else /* HOTPLUG_CPU */
#define secondaries_inhibited() 0
#endif
static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
{
struct thread_info *ti = task_thread_info(idle);
#ifdef CONFIG_PPC64
paca[cpu].__current = idle;
paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
#endif
ti->cpu = cpu;
secondary_ti = current_set[cpu] = ti;
}
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int rc, c;
/*
* Don't allow secondary threads to come online if inhibited
*/
if (threads_per_core > 1 && secondaries_inhibited() &&
cpu_thread_in_subcore(cpu))
return -EBUSY;
if (smp_ops == NULL ||
(smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
return -EINVAL;
cpu_idle_thread_init(cpu, tidle);
/* Make sure callin-map entry is 0 (can be leftover a CPU
* hotplug
*/
cpu_callin_map[cpu] = 0;
/* The information for processor bringup must
* be written out to main store before we release
* the processor.
*/
smp_mb();
/* wake up cpus */
DBG("smp: kicking cpu %d\n", cpu);
rc = smp_ops->kick_cpu(cpu);
if (rc) {
pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
return rc;
}
/*
* wait to see if the cpu made a callin (is actually up).
* use this value that I found through experimentation.
* -- Cort
*/
if (system_state < SYSTEM_RUNNING)
for (c = 50000; c && !cpu_callin_map[cpu]; c--)
udelay(100);
#ifdef CONFIG_HOTPLUG_CPU
else
/*
* CPUs can take much longer to come up in the
* hotplug case. Wait five seconds.
*/
for (c = 5000; c && !cpu_callin_map[cpu]; c--)
msleep(1);
#endif
if (!cpu_callin_map[cpu]) {
printk(KERN_ERR "Processor %u is stuck.\n", cpu);
return -ENOENT;
}
DBG("Processor %u found.\n", cpu);
if (smp_ops->give_timebase)
smp_ops->give_timebase();
/* Wait until cpu puts itself in the online map */
while (!cpu_online(cpu))
cpu_relax();
return 0;
}
/* Return the value of the reg property corresponding to the given
* logical cpu.
*/
int cpu_to_core_id(int cpu)
{
struct device_node *np;
const __be32 *reg;
int id = -1;
np = of_get_cpu_node(cpu, NULL);
if (!np)
goto out;
reg = of_get_property(np, "reg", NULL);
if (!reg)
goto out;
id = be32_to_cpup(reg);
out:
of_node_put(np);
return id;
}
/* Helper routines for cpu to core mapping */
int cpu_core_index_of_thread(int cpu)
{
return cpu >> threads_shift;
}
EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
int cpu_first_thread_of_core(int core)
{
return core << threads_shift;
}
EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
static void traverse_siblings_chip_id(int cpu, bool add, int chipid)
{
const struct cpumask *mask;
struct device_node *np;
int i, plen;
const __be32 *prop;
mask = add ? cpu_online_mask : cpu_present_mask;
for_each_cpu(i, mask) {
np = of_get_cpu_node(i, NULL);
if (!np)
continue;
prop = of_get_property(np, "ibm,chip-id", &plen);
if (prop && plen == sizeof(int) &&
of_read_number(prop, 1) == chipid) {
if (add) {
cpumask_set_cpu(cpu, cpu_core_mask(i));
cpumask_set_cpu(i, cpu_core_mask(cpu));
} else {
cpumask_clear_cpu(cpu, cpu_core_mask(i));
cpumask_clear_cpu(i, cpu_core_mask(cpu));
}
}
of_node_put(np);
}
}
/* Must be called when no change can occur to cpu_present_mask,
* i.e. during cpu online or offline.
*/
static struct device_node *cpu_to_l2cache(int cpu)
{
struct device_node *np;
struct device_node *cache;
if (!cpu_present(cpu))
return NULL;
np = of_get_cpu_node(cpu, NULL);
if (np == NULL)
return NULL;
cache = of_find_next_cache_node(np);
of_node_put(np);
return cache;
}
static void traverse_core_siblings(int cpu, bool add)
{
struct device_node *l2_cache, *np;
const struct cpumask *mask;
int i, chip, plen;
const __be32 *prop;
/* First see if we have ibm,chip-id properties in cpu nodes */
np = of_get_cpu_node(cpu, NULL);
if (np) {
chip = -1;
prop = of_get_property(np, "ibm,chip-id", &plen);
if (prop && plen == sizeof(int))
chip = of_read_number(prop, 1);
of_node_put(np);
if (chip >= 0) {
traverse_siblings_chip_id(cpu, add, chip);
return;
}
}
l2_cache = cpu_to_l2cache(cpu);
mask = add ? cpu_online_mask : cpu_present_mask;
for_each_cpu(i, mask) {
np = cpu_to_l2cache(i);
if (!np)
continue;
if (np == l2_cache) {
if (add) {
cpumask_set_cpu(cpu, cpu_core_mask(i));
cpumask_set_cpu(i, cpu_core_mask(cpu));
} else {
cpumask_clear_cpu(cpu, cpu_core_mask(i));
cpumask_clear_cpu(i, cpu_core_mask(cpu));
}
}
of_node_put(np);
}
of_node_put(l2_cache);
}
/* Activate a secondary processor. */
void start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
int i, base;
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
smp_store_cpu_info(cpu);
set_dec(tb_ticks_per_jiffy);
preempt_disable();
cpu_callin_map[cpu] = 1;
if (smp_ops->setup_cpu)
smp_ops->setup_cpu(cpu);
if (smp_ops->take_timebase)
smp_ops->take_timebase();
secondary_cpu_time_init();
#ifdef CONFIG_PPC64
if (system_state == SYSTEM_RUNNING)
vdso_data->processorCount++;
vdso_getcpu_init();
#endif
/* Update sibling maps */
base = cpu_first_thread_sibling(cpu);
for (i = 0; i < threads_per_core; i++) {
if (cpu_is_offline(base + i) && (cpu != base + i))
continue;
cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
/* cpu_core_map should be a superset of
* cpu_sibling_map even if we don't have cache
* information, so update the former here, too.
*/
cpumask_set_cpu(cpu, cpu_core_mask(base + i));
cpumask_set_cpu(base + i, cpu_core_mask(cpu));
}
traverse_core_siblings(cpu, true);
/*
* numa_node_id() works after this.
*/
set_numa_node(numa_cpu_lookup_table[cpu]);
set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
smp_wmb();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
local_irq_enable();
cpu_startup_entry(CPUHP_ONLINE);
BUG();
}
int setup_profiling_timer(unsigned int multiplier)
{
return 0;
}
void __init smp_cpus_done(unsigned int max_cpus)
{
cpumask_var_t old_mask;
/* We want the setup_cpu() here to be called from CPU 0, but our
* init thread may have been "borrowed" by another CPU in the meantime
* se we pin us down to CPU 0 for a short while
*/
alloc_cpumask_var(&old_mask, GFP_NOWAIT);
cpumask_copy(old_mask, tsk_cpus_allowed(current));
set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
if (smp_ops && smp_ops->setup_cpu)
smp_ops->setup_cpu(boot_cpuid);
set_cpus_allowed_ptr(current, old_mask);
free_cpumask_var(old_mask);
if (smp_ops && smp_ops->bringup_done)
smp_ops->bringup_done();
dump_numa_cpu_topology();
}
int arch_sd_sibling_asym_packing(void)
{
if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
return SD_ASYM_PACKING;
}
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
int cpu = smp_processor_id();
int base, i;
int err;
if (!smp_ops->cpu_disable)
return -ENOSYS;
err = smp_ops->cpu_disable();
if (err)
return err;
/* Update sibling maps */
base = cpu_first_thread_sibling(cpu);
for (i = 0; i < threads_per_core; i++) {
cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
}
traverse_core_siblings(cpu, false);
return 0;
}
void __cpu_die(unsigned int cpu)
{
if (smp_ops->cpu_die)
smp_ops->cpu_die(cpu);
}
void cpu_die(void)
{
if (ppc_md.cpu_die)
ppc_md.cpu_die();
/* If we return, we re-enter start_secondary */
start_secondary_resume();
}
#endif