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coresight: syscfg: Use IRQ-safe spinlock to protect active variables

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cscfg_config_sysfs_get_active_cfg() will be used from idle flows, while
sleeping locks are not allowed.  Introduce sysfs_store_lock to replace
the mutex to protect sysfs_active_config and sysfs_active_preset
accesses, with IRQ-safe locking to avoid lockdep complaint.

Refactor cscfg_config_sysfs_activate() to use spinlock for
sysfs_active_config and activate/deactivate config.

Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-14-f88c4a3ecfe9@arm.com
This commit is contained in:
Leo Yan 2026-05-15 21:08:21 +01:00 committed by Suzuki K Poulose
parent 81bf1c33f6
commit 3b6e3e0465
2 changed files with 22 additions and 18 deletions
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38
drivers/hwtracing/coresight/coresight-syscfg.c
View File

@ -953,39 +953,41 @@ int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool acti
unsigned long cfg_hash;
int err = 0;
mutex_lock(&cscfg_mutex);
guard(mutex)(&cscfg_mutex);
cfg_hash = (unsigned long)config_desc->event_ea->var;
if (activate) {
/* cannot be a current active value to activate this */
if (cscfg_mgr->sysfs_active_config) {
err = -EBUSY;
goto exit_unlock;
}
err = _cscfg_activate_config(cfg_hash);
if (!err)
if (cscfg_mgr->sysfs_active_config)
return -EBUSY;
scoped_guard(raw_spinlock_irqsave, &cscfg_mgr->sysfs_store_lock) {
err = _cscfg_activate_config(cfg_hash);
if (err)
return err;
cscfg_mgr->sysfs_active_config = cfg_hash;
}
} else {
/* disable if matching current value */
if (cscfg_mgr->sysfs_active_config == cfg_hash) {
if (cscfg_mgr->sysfs_active_config != cfg_hash)
return -EINVAL;
scoped_guard(raw_spinlock_irqsave, &cscfg_mgr->sysfs_store_lock) {
/* disable if matching current value */
_cscfg_deactivate_config(cfg_hash);
cscfg_mgr->sysfs_active_config = 0;
} else
err = -EINVAL;
}
}
exit_unlock:
mutex_unlock(&cscfg_mutex);
return err;
return 0;
}
/* set the sysfs preset value */
void cscfg_config_sysfs_set_preset(int preset)
{
mutex_lock(&cscfg_mutex);
guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock);
cscfg_mgr->sysfs_active_preset = preset;
mutex_unlock(&cscfg_mutex);
}
/*
@ -994,10 +996,9 @@ void cscfg_config_sysfs_set_preset(int preset)
*/
void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
{
mutex_lock(&cscfg_mutex);
guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock);
*preset = cscfg_mgr->sysfs_active_preset;
*cfg_hash = cscfg_mgr->sysfs_active_config;
mutex_unlock(&cscfg_mutex);
}
EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
@ -1201,6 +1202,7 @@ static int cscfg_create_device(void)
INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
atomic_set(&cscfg_mgr->sys_active_cnt, 0);
cscfg_mgr->load_state = CSCFG_NONE;
raw_spin_lock_init(&cscfg_mgr->sysfs_store_lock);
/* setup the device */
dev = cscfg_device();

2
drivers/hwtracing/coresight/coresight-syscfg.h
View File

@ -42,6 +42,7 @@ enum cscfg_load_ops {
* @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
* @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
* @load_state: A multi-stage load/unload operation is in progress.
* @sysfs_store_lock: Exclusive access sysfs stored variables.
*/
struct cscfg_manager {
struct device dev;
@ -54,6 +55,7 @@ struct cscfg_manager {
u32 sysfs_active_config;
int sysfs_active_preset;
enum cscfg_load_ops load_state;
raw_spinlock_t sysfs_store_lock;
};
/* get reference to dev in cscfg_manager */