args.new = BREAKPOINT_INSTRUCTION;
kcb->kprobe_status = KPROBE_SWAP_INST;
- stop_machine_run(swap_instruction, &args, NR_CPUS);
+ stop_machine(swap_instruction, &args, NULL);
kcb->kprobe_status = status;
}
args.new = p->opcode;
kcb->kprobe_status = KPROBE_SWAP_INST;
- stop_machine_run(swap_instruction, &args, NR_CPUS);
+ stop_machine(swap_instruction, &args, NULL);
kcb->kprobe_status = status;
}
* No kprobe at this address. The fault has not been
* caused by a kprobe breakpoint. The race of breakpoint
* vs. kprobe remove does not exist because on s390 we
- * use stop_machine_run to arm/disarm the breakpoints.
+ * use stop_machine to arm/disarm the breakpoints.
*/
goto no_kprobe;
struct intel_rng_hw *intel_rng_hw = _intel_rng_hw;
u8 mfc, dvc;
- /* interrupts disabled in stop_machine_run call */
+ /* interrupts disabled in stop_machine call */
if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
pci_write_config_byte(intel_rng_hw->dev,
* location with the Read ID command, all activity on the system
* must be stopped until the state is back to normal.
*
- * Use stop_machine_run because IPIs can be blocked by disabling
+ * Use stop_machine because IPIs can be blocked by disabling
* interrupts.
*/
- err = stop_machine_run(intel_rng_hw_init, intel_rng_hw, NR_CPUS);
+ err = stop_machine(intel_rng_hw_init, intel_rng_hw, NULL);
pci_dev_put(dev);
iounmap(intel_rng_hw->mem);
kfree(intel_rng_hw);
(and more). So the "read" side to such a lock is anything which
diables preeempt. */
#include <linux/cpu.h>
+#include <linux/cpumask.h>
#include <asm/system.h>
#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
+
+/* Deprecated, but useful for transition. */
+#define ALL_CPUS ~0U
+
/**
- * stop_machine_run: freeze the machine on all CPUs and run this function
+ * stop_machine: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn()
- * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
+ * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
*
- * Description: This causes a thread to be scheduled on every other cpu,
- * each of which disables interrupts, and finally interrupts are disabled
- * on the current CPU. The result is that noone is holding a spinlock
- * or inside any other preempt-disabled region when @fn() runs.
+ * Description: This causes a thread to be scheduled on every cpu,
+ * each of which disables interrupts. The result is that noone is
+ * holding a spinlock or inside any other preempt-disabled region when
+ * @fn() runs.
*
* This can be thought of as a very heavy write lock, equivalent to
* grabbing every spinlock in the kernel. */
-int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
+int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
/**
- * __stop_machine_run: freeze the machine on all CPUs and run this function
+ * __stop_machine: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn
- * @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
+ * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
*
- * Description: This is a special version of the above, which returns the
- * thread which has run @fn(): kthread_stop will return the return value
- * of @fn(). Used by hotplug cpu.
+ * Description: This is a special version of the above, which assumes cpus
+ * won't come or go while it's being called. Used by hotplug cpu.
*/
-struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu);
-
+int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
#else
-static inline int stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu)
+static inline int stop_machine(int (*fn)(void *), void *data,
+ const cpumask_t *cpus)
{
int ret;
local_irq_disable();
return ret;
}
#endif /* CONFIG_SMP */
+
+static inline int __deprecated stop_machine_run(int (*fn)(void *), void *data,
+ unsigned int cpu)
+{
+ /* If they don't care which cpu fn runs on, just pick one. */
+ if (cpu == NR_CPUS)
+ return stop_machine(fn, data, NULL);
+ else if (cpu == ~0U)
+ return stop_machine(fn, data, &cpu_possible_map);
+ else {
+ cpumask_t cpus = cpumask_of_cpu(cpu);
+ return stop_machine(fn, data, &cpus);
+ }
+}
#endif /* _LINUX_STOP_MACHINE */
static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
{
int err, nr_calls = 0;
- struct task_struct *p;
cpumask_t old_allowed, tmp;
void *hcpu = (void *)(long)cpu;
unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
cpus_setall(tmp);
cpu_clear(cpu, tmp);
set_cpus_allowed_ptr(current, &tmp);
+ tmp = cpumask_of_cpu(cpu);
- p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
-
- if (IS_ERR(p) || cpu_online(cpu)) {
+ err = __stop_machine(take_cpu_down, &tcd_param, &tmp);
+ if (err) {
/* CPU didn't die: tell everyone. Can't complain. */
if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
hcpu) == NOTIFY_BAD)
BUG();
- if (IS_ERR(p)) {
- err = PTR_ERR(p);
- goto out_allowed;
- }
- goto out_thread;
+ goto out_allowed;
}
+ BUG_ON(cpu_online(cpu));
/* Wait for it to sleep (leaving idle task). */
while (!idle_cpu(cpu))
check_for_tasks(cpu);
-out_thread:
- err = kthread_stop(p);
out_allowed:
set_cpus_allowed_ptr(current, &old_allowed);
out_release:
return -ENOENT;
}
-/* lookup symbol in given range of kernel_symbols */
-static const struct kernel_symbol *lookup_symbol(const char *name,
- const struct kernel_symbol *start,
- const struct kernel_symbol *stop)
-{
- const struct kernel_symbol *ks = start;
- for (; ks < stop; ks++)
- if (strcmp(ks->name, name) == 0)
- return ks;
- return NULL;
-}
-
/* Search for module by name: must hold module_mutex. */
static struct module *find_module(const char *name)
{
if (flags & O_NONBLOCK) {
struct stopref sref = { mod, flags, forced };
- return stop_machine_run(__try_stop_module, &sref, NR_CPUS);
+ return stop_machine(__try_stop_module, &sref, NULL);
} else {
/* We don't need to stop the machine for this. */
mod->state = MODULE_STATE_GOING;
static void free_module(struct module *mod)
{
/* Delete from various lists */
- stop_machine_run(__unlink_module, mod, NR_CPUS);
+ stop_machine(__unlink_module, mod, NULL);
remove_notes_attrs(mod);
remove_sect_attrs(mod);
mod_kobject_remove(mod);
}
#ifdef CONFIG_KALLSYMS
+
+/* lookup symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_symbol(const char *name,
+ const struct kernel_symbol *start,
+ const struct kernel_symbol *stop)
+{
+ const struct kernel_symbol *ks = start;
+ for (; ks < stop; ks++)
+ if (strcmp(ks->name, name) == 0)
+ return ks;
+ return NULL;
+}
+
static int is_exported(const char *name, const struct module *mod)
{
if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
/* Now sew it into the lists so we can get lockdep and oops
* info during argument parsing. Noone should access us, since
* strong_try_module_get() will fail. */
- stop_machine_run(__link_module, mod, NR_CPUS);
+ stop_machine(__link_module, mod, NULL);
/* Size of section 0 is 0, so this works well if no params */
err = parse_args(mod->name, mod->args,
return mod;
unlink:
- stop_machine_run(__unlink_module, mod, NR_CPUS);
+ stop_machine(__unlink_module, mod, NULL);
module_arch_cleanup(mod);
cleanup:
kobject_del(&mod->mkobj.kobj);
* rdp->cpu is the current cpu.
*
* cpu_online_map is updated by the _cpu_down()
- * using stop_machine_run(). Since we're in irqs disabled
- * section, stop_machine_run() is not exectuting, hence
+ * using __stop_machine(). Since we're in irqs disabled
+ * section, __stop_machine() is not exectuting, hence
* the cpu_online_map is stable.
*
* However, a cpu might have been offlined _just_ before
-/* Copyright 2005 Rusty Russell rusty@rustcorp.com.au IBM Corporation.
+/* Copyright 2008, 2005 Rusty Russell rusty@rustcorp.com.au IBM Corporation.
* GPL v2 and any later version.
*/
#include <linux/cpu.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
-/* Since we effect priority and affinity (both of which are visible
- * to, and settable by outside processes) we do indirection via a
- * kthread. */
-
-/* Thread to stop each CPU in user context. */
+/* This controls the threads on each CPU. */
enum stopmachine_state {
- STOPMACHINE_WAIT,
+ /* Dummy starting state for thread. */
+ STOPMACHINE_NONE,
+ /* Awaiting everyone to be scheduled. */
STOPMACHINE_PREPARE,
+ /* Disable interrupts. */
STOPMACHINE_DISABLE_IRQ,
+ /* Run the function */
+ STOPMACHINE_RUN,
+ /* Exit */
STOPMACHINE_EXIT,
};
+static enum stopmachine_state state;
-static enum stopmachine_state stopmachine_state;
-static unsigned int stopmachine_num_threads;
-static atomic_t stopmachine_thread_ack;
-
-static int stopmachine(void *cpu)
-{
- int irqs_disabled = 0;
- int prepared = 0;
- cpumask_of_cpu_ptr(cpumask, (int)(long)cpu);
-
- set_cpus_allowed_ptr(current, cpumask);
-
- /* Ack: we are alive */
- smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
- atomic_inc(&stopmachine_thread_ack);
-
- /* Simple state machine */
- while (stopmachine_state != STOPMACHINE_EXIT) {
- if (stopmachine_state == STOPMACHINE_DISABLE_IRQ
- && !irqs_disabled) {
- local_irq_disable();
- hard_irq_disable();
- irqs_disabled = 1;
- /* Ack: irqs disabled. */
- smp_mb(); /* Must read state first. */
- atomic_inc(&stopmachine_thread_ack);
- } else if (stopmachine_state == STOPMACHINE_PREPARE
- && !prepared) {
- /* Everyone is in place, hold CPU. */
- preempt_disable();
- prepared = 1;
- smp_mb(); /* Must read state first. */
- atomic_inc(&stopmachine_thread_ack);
- }
- /* Yield in first stage: migration threads need to
- * help our sisters onto their CPUs. */
- if (!prepared && !irqs_disabled)
- yield();
- cpu_relax();
- }
-
- /* Ack: we are exiting. */
- smp_mb(); /* Must read state first. */
- atomic_inc(&stopmachine_thread_ack);
-
- if (irqs_disabled)
- local_irq_enable();
- if (prepared)
- preempt_enable();
+struct stop_machine_data {
+ int (*fn)(void *);
+ void *data;
+ int fnret;
+};
- return 0;
-}
+/* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */
+static unsigned int num_threads;
+static atomic_t thread_ack;
+static struct completion finished;
+static DEFINE_MUTEX(lock);
-/* Change the thread state */
-static void stopmachine_set_state(enum stopmachine_state state)
+static void set_state(enum stopmachine_state newstate)
{
- atomic_set(&stopmachine_thread_ack, 0);
+ /* Reset ack counter. */
+ atomic_set(&thread_ack, num_threads);
smp_wmb();
- stopmachine_state = state;
- while (atomic_read(&stopmachine_thread_ack) != stopmachine_num_threads)
- cpu_relax();
+ state = newstate;
}
-static int stop_machine(void)
+/* Last one to ack a state moves to the next state. */
+static void ack_state(void)
{
- int i, ret = 0;
-
- atomic_set(&stopmachine_thread_ack, 0);
- stopmachine_num_threads = 0;
- stopmachine_state = STOPMACHINE_WAIT;
-
- for_each_online_cpu(i) {
- if (i == raw_smp_processor_id())
- continue;
- ret = kernel_thread(stopmachine, (void *)(long)i,CLONE_KERNEL);
- if (ret < 0)
- break;
- stopmachine_num_threads++;
- }
-
- /* Wait for them all to come to life. */
- while (atomic_read(&stopmachine_thread_ack) != stopmachine_num_threads) {
- yield();
- cpu_relax();
+ if (atomic_dec_and_test(&thread_ack)) {
+ /* If we're the last one to ack the EXIT, we're finished. */
+ if (state == STOPMACHINE_EXIT)
+ complete(&finished);
+ else
+ set_state(state + 1);
}
+}
- /* If some failed, kill them all. */
- if (ret < 0) {
- stopmachine_set_state(STOPMACHINE_EXIT);
- return ret;
- }
+/* This is the actual thread which stops the CPU. It exits by itself rather
+ * than waiting for kthread_stop(), because it's easier for hotplug CPU. */
+static int stop_cpu(struct stop_machine_data *smdata)
+{
+ enum stopmachine_state curstate = STOPMACHINE_NONE;
+ int uninitialized_var(ret);
- /* Now they are all started, make them hold the CPUs, ready. */
- preempt_disable();
- stopmachine_set_state(STOPMACHINE_PREPARE);
+ /* Simple state machine */
+ do {
+ /* Chill out and ensure we re-read stopmachine_state. */
+ cpu_relax();
+ if (state != curstate) {
+ curstate = state;
+ switch (curstate) {
+ case STOPMACHINE_DISABLE_IRQ:
+ local_irq_disable();
+ hard_irq_disable();
+ break;
+ case STOPMACHINE_RUN:
+ /* |= allows error detection if functions on
+ * multiple CPUs. */
+ smdata->fnret |= smdata->fn(smdata->data);
+ break;
+ default:
+ break;
+ }
+ ack_state();
+ }
+ } while (curstate != STOPMACHINE_EXIT);
- /* Make them disable irqs. */
- local_irq_disable();
- hard_irq_disable();
- stopmachine_set_state(STOPMACHINE_DISABLE_IRQ);
+ local_irq_enable();
+ do_exit(0);
+}
+/* Callback for CPUs which aren't supposed to do anything. */
+static int chill(void *unused)
+{
return 0;
}
-static void restart_machine(void)
+int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
{
- stopmachine_set_state(STOPMACHINE_EXIT);
- local_irq_enable();
- preempt_enable_no_resched();
-}
+ int i, err;
+ struct stop_machine_data active, idle;
+ struct task_struct **threads;
+
+ active.fn = fn;
+ active.data = data;
+ active.fnret = 0;
+ idle.fn = chill;
+ idle.data = NULL;
+
+ /* This could be too big for stack on large machines. */
+ threads = kcalloc(NR_CPUS, sizeof(threads[0]), GFP_KERNEL);
+ if (!threads)
+ return -ENOMEM;
+
+ /* Set up initial state. */
+ mutex_lock(&lock);
+ init_completion(&finished);
+ num_threads = num_online_cpus();
+ set_state(STOPMACHINE_PREPARE);
-struct stop_machine_data {
- int (*fn)(void *);
- void *data;
- struct completion done;
-};
+ for_each_online_cpu(i) {
+ struct stop_machine_data *smdata = &idle;
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-static int do_stop(void *_smdata)
-{
- struct stop_machine_data *smdata = _smdata;
- int ret;
+ if (!cpus) {
+ if (i == first_cpu(cpu_online_map))
+ smdata = &active;
+ } else {
+ if (cpu_isset(i, *cpus))
+ smdata = &active;
+ }
- ret = stop_machine();
- if (ret == 0) {
- ret = smdata->fn(smdata->data);
- restart_machine();
- }
+ threads[i] = kthread_create((void *)stop_cpu, smdata, "kstop%u",
+ i);
+ if (IS_ERR(threads[i])) {
+ err = PTR_ERR(threads[i]);
+ threads[i] = NULL;
+ goto kill_threads;
+ }
- /* We're done: you can kthread_stop us now */
- complete(&smdata->done);
+ /* Place it onto correct cpu. */
+ kthread_bind(threads[i], i);
- /* Wait for kthread_stop */
- set_current_state(TASK_INTERRUPTIBLE);
- while (!kthread_should_stop()) {
- schedule();
- set_current_state(TASK_INTERRUPTIBLE);
+ /* Make it highest prio. */
+ if (sched_setscheduler_nocheck(threads[i], SCHED_FIFO, ¶m))
+ BUG();
}
- __set_current_state(TASK_RUNNING);
- return ret;
-}
-struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu)
-{
- static DEFINE_MUTEX(stopmachine_mutex);
- struct stop_machine_data smdata;
- struct task_struct *p;
+ /* We've created all the threads. Wake them all: hold this CPU so one
+ * doesn't hit this CPU until we're ready. */
+ get_cpu();
+ for_each_online_cpu(i)
+ wake_up_process(threads[i]);
- smdata.fn = fn;
- smdata.data = data;
- init_completion(&smdata.done);
+ /* This will release the thread on our CPU. */
+ put_cpu();
+ wait_for_completion(&finished);
+ mutex_unlock(&lock);
- mutex_lock(&stopmachine_mutex);
+ kfree(threads);
- /* If they don't care which CPU fn runs on, bind to any online one. */
- if (cpu == NR_CPUS)
- cpu = raw_smp_processor_id();
+ return active.fnret;
- p = kthread_create(do_stop, &smdata, "kstopmachine");
- if (!IS_ERR(p)) {
- struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+kill_threads:
+ for_each_online_cpu(i)
+ if (threads[i])
+ kthread_stop(threads[i]);
+ mutex_unlock(&lock);
- /* One high-prio thread per cpu. We'll do this one. */
- sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m);
- kthread_bind(p, cpu);
- wake_up_process(p);
- wait_for_completion(&smdata.done);
- }
- mutex_unlock(&stopmachine_mutex);
- return p;
+ kfree(threads);
+ return err;
}
-int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu)
+int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
{
- struct task_struct *p;
int ret;
/* No CPUs can come up or down during this. */
get_online_cpus();
- p = __stop_machine_run(fn, data, cpu);
- if (!IS_ERR(p))
- ret = kthread_stop(p);
- else
- ret = PTR_ERR(p);
+ ret = __stop_machine(fn, data, cpus);
put_online_cpus();
return ret;
}
-EXPORT_SYMBOL_GPL(stop_machine_run);
+EXPORT_SYMBOL_GPL(stop_machine);
static void ftrace_run_update_code(int command)
{
- stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
+ stop_machine(__ftrace_modify_code, &command, NULL);
}
void ftrace_disable_daemon(void)
!ftrace_enabled || !ftraced_trigger)
return 0;
- stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
+ stop_machine(__ftrace_update_code, NULL, NULL);
return 1;
}
addr = (unsigned long)ftrace_record_ip;
- stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
+ stop_machine(ftrace_dyn_arch_init, &addr, NULL);
/* ftrace_dyn_arch_init places the return code in addr */
if (addr) {
#endif /* CONFIG_NUMA */
-/* return values int ....just for stop_machine_run() */
+/* return values int ....just for stop_machine() */
static int __build_all_zonelists(void *dummy)
{
int nid;
} else {
/* we have to stop all cpus to guarantee there is no user
of zonelist */
- stop_machine_run(__build_all_zonelists, NULL, NR_CPUS);
+ stop_machine(__build_all_zonelists, NULL, NULL);
/* cpuset refresh routine should be here */
}
vm_total_pages = nr_free_pagecache_pages();
projects / linux-2.6-omap-h63xx.git / commitdiff