Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/smp.c b/kernel/smp.c
index 3a39093..f73a597 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -14,19 +14,21 @@
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/sched/idle.h>
#include <linux/hypervisor.h>
+#include <linux/sched/clock.h>
+#include <linux/nmi.h>
+#include <linux/sched/debug.h>
#include "smpboot.h"
+#include "sched/smp.h"
-enum {
- CSD_FLAG_LOCK = 0x01,
- CSD_FLAG_SYNCHRONOUS = 0x02,
-};
+#define CSD_TYPE(_csd) ((_csd)->flags & CSD_FLAG_TYPE_MASK)
struct call_function_data {
call_single_data_t __percpu *csd;
@@ -84,6 +86,7 @@
* still pending.
*/
flush_smp_call_function_queue(false);
+ irq_work_run();
return 0;
}
@@ -97,6 +100,103 @@
smpcfd_prepare_cpu(smp_processor_id());
}
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+
+static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
+static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);
+static DEFINE_PER_CPU(void *, cur_csd_info);
+
+#define CSD_LOCK_TIMEOUT (5ULL * NSEC_PER_SEC)
+static atomic_t csd_bug_count = ATOMIC_INIT(0);
+
+/* Record current CSD work for current CPU, NULL to erase. */
+static void csd_lock_record(struct __call_single_data *csd)
+{
+ if (!csd) {
+ smp_mb(); /* NULL cur_csd after unlock. */
+ __this_cpu_write(cur_csd, NULL);
+ return;
+ }
+ __this_cpu_write(cur_csd_func, csd->func);
+ __this_cpu_write(cur_csd_info, csd->info);
+ smp_wmb(); /* func and info before csd. */
+ __this_cpu_write(cur_csd, csd);
+ smp_mb(); /* Update cur_csd before function call. */
+ /* Or before unlock, as the case may be. */
+}
+
+static __always_inline int csd_lock_wait_getcpu(struct __call_single_data *csd)
+{
+ unsigned int csd_type;
+
+ csd_type = CSD_TYPE(csd);
+ if (csd_type == CSD_TYPE_ASYNC || csd_type == CSD_TYPE_SYNC)
+ return csd->dst; /* Other CSD_TYPE_ values might not have ->dst. */
+ return -1;
+}
+
+/*
+ * Complain if too much time spent waiting. Note that only
+ * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
+ * so waiting on other types gets much less information.
+ */
+static __always_inline bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *ts1, int *bug_id)
+{
+ int cpu = -1;
+ int cpux;
+ bool firsttime;
+ u64 ts2, ts_delta;
+ call_single_data_t *cpu_cur_csd;
+ unsigned int flags = READ_ONCE(csd->flags);
+
+ if (!(flags & CSD_FLAG_LOCK)) {
+ if (!unlikely(*bug_id))
+ return true;
+ cpu = csd_lock_wait_getcpu(csd);
+ pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n",
+ *bug_id, raw_smp_processor_id(), cpu);
+ return true;
+ }
+
+ ts2 = sched_clock();
+ ts_delta = ts2 - *ts1;
+ if (likely(ts_delta <= CSD_LOCK_TIMEOUT))
+ return false;
+
+ firsttime = !*bug_id;
+ if (firsttime)
+ *bug_id = atomic_inc_return(&csd_bug_count);
+ cpu = csd_lock_wait_getcpu(csd);
+ if (WARN_ONCE(cpu < 0 || cpu >= nr_cpu_ids, "%s: cpu = %d\n", __func__, cpu))
+ cpux = 0;
+ else
+ cpux = cpu;
+ cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */
+ pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n",
+ firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts2 - ts0,
+ cpu, csd->func, csd->info);
+ if (cpu_cur_csd && csd != cpu_cur_csd) {
+ pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n",
+ *bug_id, READ_ONCE(per_cpu(cur_csd_func, cpux)),
+ READ_ONCE(per_cpu(cur_csd_info, cpux)));
+ } else {
+ pr_alert("\tcsd: CSD lock (#%d) %s.\n",
+ *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
+ }
+ if (cpu >= 0) {
+ if (!trigger_single_cpu_backtrace(cpu))
+ dump_cpu_task(cpu);
+ if (!cpu_cur_csd) {
+ pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
+ arch_send_call_function_single_ipi(cpu);
+ }
+ }
+ dump_stack();
+ *ts1 = ts2;
+
+ return false;
+}
+
/*
* csd_lock/csd_unlock used to serialize access to per-cpu csd resources
*
@@ -106,8 +206,28 @@
*/
static __always_inline void csd_lock_wait(struct __call_single_data *csd)
{
+ int bug_id = 0;
+ u64 ts0, ts1;
+
+ ts1 = ts0 = sched_clock();
+ for (;;) {
+ if (csd_lock_wait_toolong(csd, ts0, &ts1, &bug_id))
+ break;
+ cpu_relax();
+ }
+ smp_acquire__after_ctrl_dep();
+}
+
+#else
+static void csd_lock_record(struct __call_single_data *csd)
+{
+}
+
+static __always_inline void csd_lock_wait(struct __call_single_data *csd)
+{
smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK));
}
+#endif
static __always_inline void csd_lock(struct __call_single_data *csd)
{
@@ -134,37 +254,8 @@
static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
-/*
- * Insert a previously allocated call_single_data_t element
- * for execution on the given CPU. data must already have
- * ->func, ->info, and ->flags set.
- */
-static int generic_exec_single(int cpu, struct __call_single_data *csd,
- smp_call_func_t func, void *info)
+void __smp_call_single_queue(int cpu, struct llist_node *node)
{
- if (cpu == smp_processor_id()) {
- unsigned long flags;
-
- /*
- * We can unlock early even for the synchronous on-stack case,
- * since we're doing this from the same CPU..
- */
- csd_unlock(csd);
- local_irq_save(flags);
- func(info);
- local_irq_restore(flags);
- return 0;
- }
-
-
- if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
- csd_unlock(csd);
- return -ENXIO;
- }
-
- csd->func = func;
- csd->info = info;
-
/*
* The list addition should be visible before sending the IPI
* handler locks the list to pull the entry off it because of
@@ -176,8 +267,41 @@
* locking and barrier primitives. Generic code isn't really
* equipped to do the right thing...
*/
- if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
- arch_send_call_function_single_ipi(cpu);
+ if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+ send_call_function_single_ipi(cpu);
+}
+
+/*
+ * Insert a previously allocated call_single_data_t element
+ * for execution on the given CPU. data must already have
+ * ->func, ->info, and ->flags set.
+ */
+static int generic_exec_single(int cpu, struct __call_single_data *csd)
+{
+ if (cpu == smp_processor_id()) {
+ smp_call_func_t func = csd->func;
+ void *info = csd->info;
+ unsigned long flags;
+
+ /*
+ * We can unlock early even for the synchronous on-stack case,
+ * since we're doing this from the same CPU..
+ */
+ csd_lock_record(csd);
+ csd_unlock(csd);
+ local_irq_save(flags);
+ func(info);
+ csd_lock_record(NULL);
+ local_irq_restore(flags);
+ return 0;
+ }
+
+ if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
+ csd_unlock(csd);
+ return -ENXIO;
+ }
+
+ __smp_call_single_queue(cpu, &csd->llist);
return 0;
}
@@ -209,9 +333,9 @@
*/
static void flush_smp_call_function_queue(bool warn_cpu_offline)
{
- struct llist_head *head;
- struct llist_node *entry;
call_single_data_t *csd, *csd_next;
+ struct llist_node *entry, *prev;
+ struct llist_head *head;
static bool warned;
lockdep_assert_irqs_disabled();
@@ -230,32 +354,106 @@
* We don't have to use the _safe() variant here
* because we are not invoking the IPI handlers yet.
*/
- llist_for_each_entry(csd, entry, llist)
- pr_warn("IPI callback %pS sent to offline CPU\n",
- csd->func);
- }
+ llist_for_each_entry(csd, entry, llist) {
+ switch (CSD_TYPE(csd)) {
+ case CSD_TYPE_ASYNC:
+ case CSD_TYPE_SYNC:
+ case CSD_TYPE_IRQ_WORK:
+ pr_warn("IPI callback %pS sent to offline CPU\n",
+ csd->func);
+ break;
- llist_for_each_entry_safe(csd, csd_next, entry, llist) {
- smp_call_func_t func = csd->func;
- void *info = csd->info;
+ case CSD_TYPE_TTWU:
+ pr_warn("IPI task-wakeup sent to offline CPU\n");
+ break;
- /* Do we wait until *after* callback? */
- if (csd->flags & CSD_FLAG_SYNCHRONOUS) {
- func(info);
- csd_unlock(csd);
- } else {
- csd_unlock(csd);
- func(info);
+ default:
+ pr_warn("IPI callback, unknown type %d, sent to offline CPU\n",
+ CSD_TYPE(csd));
+ break;
+ }
}
}
/*
- * Handle irq works queued remotely by irq_work_queue_on().
- * Smp functions above are typically synchronous so they
- * better run first since some other CPUs may be busy waiting
- * for them.
+ * First; run all SYNC callbacks, people are waiting for us.
*/
- irq_work_run();
+ prev = NULL;
+ llist_for_each_entry_safe(csd, csd_next, entry, llist) {
+ /* Do we wait until *after* callback? */
+ if (CSD_TYPE(csd) == CSD_TYPE_SYNC) {
+ smp_call_func_t func = csd->func;
+ void *info = csd->info;
+
+ if (prev) {
+ prev->next = &csd_next->llist;
+ } else {
+ entry = &csd_next->llist;
+ }
+
+ csd_lock_record(csd);
+ func(info);
+ csd_unlock(csd);
+ csd_lock_record(NULL);
+ } else {
+ prev = &csd->llist;
+ }
+ }
+
+ if (!entry)
+ return;
+
+ /*
+ * Second; run all !SYNC callbacks.
+ */
+ prev = NULL;
+ llist_for_each_entry_safe(csd, csd_next, entry, llist) {
+ int type = CSD_TYPE(csd);
+
+ if (type != CSD_TYPE_TTWU) {
+ if (prev) {
+ prev->next = &csd_next->llist;
+ } else {
+ entry = &csd_next->llist;
+ }
+
+ if (type == CSD_TYPE_ASYNC) {
+ smp_call_func_t func = csd->func;
+ void *info = csd->info;
+
+ csd_lock_record(csd);
+ csd_unlock(csd);
+ func(info);
+ csd_lock_record(NULL);
+ } else if (type == CSD_TYPE_IRQ_WORK) {
+ irq_work_single(csd);
+ }
+
+ } else {
+ prev = &csd->llist;
+ }
+ }
+
+ /*
+ * Third; only CSD_TYPE_TTWU is left, issue those.
+ */
+ if (entry)
+ sched_ttwu_pending(entry);
+}
+
+void flush_smp_call_function_from_idle(void)
+{
+ unsigned long flags;
+
+ if (llist_empty(this_cpu_ptr(&call_single_queue)))
+ return;
+
+ local_irq_save(flags);
+ flush_smp_call_function_queue(true);
+ if (local_softirq_pending())
+ do_softirq();
+
+ local_irq_restore(flags);
}
/*
@@ -271,7 +469,7 @@
{
call_single_data_t *csd;
call_single_data_t csd_stack = {
- .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS,
+ .flags = CSD_FLAG_LOCK | CSD_TYPE_SYNC,
};
int this_cpu;
int err;
@@ -305,7 +503,14 @@
csd_lock(csd);
}
- err = generic_exec_single(cpu, csd, func, info);
+ csd->func = func;
+ csd->info = info;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+ csd->src = smp_processor_id();
+ csd->dst = cpu;
+#endif
+
+ err = generic_exec_single(cpu, csd);
if (wait)
csd_lock_wait(csd);
@@ -329,6 +534,11 @@
* (ie: embedded in an object) and is responsible for synchronizing it
* such that the IPIs performed on the @csd are strictly serialized.
*
+ * If the function is called with one csd which has not yet been
+ * processed by previous call to smp_call_function_single_async(), the
+ * function will return immediately with -EBUSY showing that the csd
+ * object is still in progress.
+ *
* NOTE: Be careful, there is unfortunately no current debugging facility to
* validate the correctness of this serialization.
*/
@@ -338,14 +548,17 @@
preempt_disable();
- /* We could deadlock if we have to wait here with interrupts disabled! */
- if (WARN_ON_ONCE(csd->flags & CSD_FLAG_LOCK))
- csd_lock_wait(csd);
+ if (csd->flags & CSD_FLAG_LOCK) {
+ err = -EBUSY;
+ goto out;
+ }
csd->flags = CSD_FLAG_LOCK;
smp_wmb();
- err = generic_exec_single(cpu, csd, csd->func, csd->info);
+ err = generic_exec_single(cpu, csd);
+
+out:
preempt_enable();
return err;
@@ -395,22 +608,9 @@
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
-/**
- * smp_call_function_many(): Run a function on a set of other CPUs.
- * @mask: The set of cpus to run on (only runs on online subset).
- * @func: The function to run. This must be fast and non-blocking.
- * @info: An arbitrary pointer to pass to the function.
- * @wait: If true, wait (atomically) until function has completed
- * on other CPUs.
- *
- * If @wait is true, then returns once @func has returned.
- *
- * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler or from a bottom half handler. Preemption
- * must be disabled when calling this function.
- */
-void smp_call_function_many(const struct cpumask *mask,
- smp_call_func_t func, void *info, bool wait)
+static void smp_call_function_many_cond(const struct cpumask *mask,
+ smp_call_func_t func, void *info,
+ bool wait, smp_cond_func_t cond_func)
{
struct call_function_data *cfd;
int cpu, next_cpu, this_cpu = smp_processor_id();
@@ -448,7 +648,8 @@
/* Fastpath: do that cpu by itself. */
if (next_cpu >= nr_cpu_ids) {
- smp_call_function_single(cpu, func, info, wait);
+ if (!cond_func || cond_func(cpu, info))
+ smp_call_function_single(cpu, func, info, wait);
return;
}
@@ -465,11 +666,18 @@
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
+ if (cond_func && !cond_func(cpu, info))
+ continue;
+
csd_lock(csd);
if (wait)
- csd->flags |= CSD_FLAG_SYNCHRONOUS;
+ csd->flags |= CSD_TYPE_SYNC;
csd->func = func;
csd->info = info;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+ csd->src = smp_processor_id();
+ csd->dst = cpu;
+#endif
if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
}
@@ -486,6 +694,26 @@
}
}
}
+
+/**
+ * smp_call_function_many(): Run a function on a set of other CPUs.
+ * @mask: The set of cpus to run on (only runs on online subset).
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed
+ * on other CPUs.
+ *
+ * If @wait is true, then returns once @func has returned.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler. Preemption
+ * must be disabled when calling this function.
+ */
+void smp_call_function_many(const struct cpumask *mask,
+ smp_call_func_t func, void *info, bool wait)
+{
+ smp_call_function_many_cond(mask, func, info, wait, NULL);
+}
EXPORT_SYMBOL(smp_call_function_many);
/**
@@ -544,8 +772,7 @@
{
int nr_cpus;
- get_option(&str, &nr_cpus);
- if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
+ if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids)
nr_cpu_ids = nr_cpus;
return 0;
@@ -578,20 +805,13 @@
void __init smp_init(void)
{
int num_nodes, num_cpus;
- unsigned int cpu;
idle_threads_init();
cpuhp_threads_init();
pr_info("Bringing up secondary CPUs ...\n");
- /* FIXME: This should be done in userspace --RR */
- for_each_present_cpu(cpu) {
- if (num_online_cpus() >= setup_max_cpus)
- break;
- if (!cpu_online(cpu))
- cpu_up(cpu);
- }
+ bringup_nonboot_cpus(setup_max_cpus);
num_nodes = num_online_nodes();
num_cpus = num_online_cpus();
@@ -608,7 +828,7 @@
* early_boot_irqs_disabled is set. Use local_irq_save/restore() instead
* of local_irq_disable/enable().
*/
-void on_each_cpu(void (*func) (void *info), void *info, int wait)
+void on_each_cpu(smp_call_func_t func, void *info, int wait)
{
unsigned long flags;
@@ -659,7 +879,7 @@
* for all the required CPUs to finish. This may include the local
* processor.
* @cond_func: A callback function that is passed a cpu id and
- * the the info parameter. The function is called
+ * the info parameter. The function is called
* with preemption disabled. The function should
* return a blooean value indicating whether to IPI
* the specified CPU.
@@ -668,11 +888,6 @@
* @info: An arbitrary pointer to pass to both functions.
* @wait: If true, wait (atomically) until function has
* completed on other CPUs.
- * @gfp_flags: GFP flags to use when allocating the cpumask
- * used internally by the function.
- *
- * The function might sleep if the GFP flags indicates a non
- * atomic allocation is allowed.
*
* Preemption is disabled to protect against CPUs going offline but not online.
* CPUs going online during the call will not be seen or sent an IPI.
@@ -680,46 +895,27 @@
* You must not call this function with disabled interrupts or
* from a hardware interrupt handler or from a bottom half handler.
*/
-void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),
- smp_call_func_t func, void *info, bool wait,
- gfp_t gfp_flags, const struct cpumask *mask)
+void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
+ void *info, bool wait, const struct cpumask *mask)
{
- cpumask_var_t cpus;
- int cpu, ret;
+ int cpu = get_cpu();
- might_sleep_if(gfpflags_allow_blocking(gfp_flags));
+ smp_call_function_many_cond(mask, func, info, wait, cond_func);
+ if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) {
+ unsigned long flags;
- if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
- preempt_disable();
- for_each_cpu(cpu, mask)
- if (cond_func(cpu, info))
- __cpumask_set_cpu(cpu, cpus);
- on_each_cpu_mask(cpus, func, info, wait);
- preempt_enable();
- free_cpumask_var(cpus);
- } else {
- /*
- * No free cpumask, bother. No matter, we'll
- * just have to IPI them one by one.
- */
- preempt_disable();
- for_each_cpu(cpu, mask)
- if (cond_func(cpu, info)) {
- ret = smp_call_function_single(cpu, func,
- info, wait);
- WARN_ON_ONCE(ret);
- }
- preempt_enable();
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
}
+ put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
-void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
- smp_call_func_t func, void *info, bool wait,
- gfp_t gfp_flags)
+void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
+ void *info, bool wait)
{
- on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags,
- cpu_online_mask);
+ on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
}
EXPORT_SYMBOL(on_each_cpu_cond);