[PATCH v15 2/7] coresight: tmc: add create/clean functions for etr_buf_list
Jie Gan
jie.gan at oss.qualcomm.com
Tue Mar 17 18:06:18 PDT 2026
On 3/17/2026 7:01 PM, Suzuki K Poulose wrote:
> On 13/03/2026 09:02, Jie Gan wrote:
>> Introduce functions for creating and inserting or removing the
>> etr_buf_node to/from the etr_buf_list.
>>
>> The byte-cntr functionality requires two etr_buf to receive trace data.
>> The active etr_buf collects the trace data from source device, while the
>> byte-cntr reading function accesses the deactivated etr_buf after is
>> has been filled and synced, transferring data to the userspace.
>>
>> Reviewed-by: Mike Leach <mike.leach at linaro.org>
>> Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
>> ---
>> drivers/hwtracing/coresight/coresight-tmc-core.c | 1 +
>> drivers/hwtracing/coresight/coresight-tmc-etr.c | 108 +++++++++++++
>> ++++++++++
>> drivers/hwtracing/coresight/coresight-tmc.h | 17 ++++
>> 3 files changed, 126 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/
>> drivers/hwtracing/coresight/coresight-tmc-core.c
>> index c89fe996af23..bac3278ef4dd 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
>> @@ -835,6 +835,7 @@ static int __tmc_probe(struct device *dev, struct
>> resource *res)
>> idr_init(&drvdata->idr);
>> mutex_init(&drvdata->idr_mutex);
>> dev_list = "tmc_etr";
>> + INIT_LIST_HEAD(&drvdata->etr_buf_list);
>> break;
>> case TMC_CONFIG_TYPE_ETF:
>> desc.groups = coresight_etf_groups;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/
>> drivers/hwtracing/coresight/coresight-tmc-etr.c
>> index 4dc1defe27a5..fdf23e1c932f 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> @@ -1918,6 +1918,114 @@ const struct coresight_ops tmc_etr_cs_ops = {
>> .panic_ops = &tmc_etr_sync_ops,
>> };
>> +/**
>> + * tmc_clean_etr_buf_list - clean the etr_buf_list.
>> + * @drvdata: driver data of the TMC device.
>> + *
>> + * Remove unused buffers from @drvdata->etr_buf_list and free them.
>> + */
>> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata)
>> +{
>> + struct etr_buf_node *nd, *next;
>> + unsigned long flags;
>> +
>> + lockdep_assert_held(&drvdata->spinlock);
>> + list_for_each_entry_safe(nd, next, &drvdata->etr_buf_list, link) {
>> + if (nd->sysfs_buf == drvdata->sysfs_buf) {
>> + if (coresight_get_mode(drvdata->csdev) !=
>> CS_MODE_DISABLED) {
>> + /*
>> + * Dont free the sysfs_buf, just remove it from list.
>> + * drvdata->sysfs_buf will hold the buffer and free
>> it later.
>> + */
>> + nd->sysfs_buf = NULL;
>> + list_del(&nd->link);
>> + kfree(nd);
>> + continue;
>> + }
>> + }
>> + /* Free allocated buffers which are not utilized by ETR */
>> + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
>
> This is dangerous ! Restoring the irqflags to an uninitialised value
> from a different function thant where it was locked. Please clean this up
>
Noted, will take care of it in the future.
Thanks,
Jie
> Suzuki
>
>
>> + tmc_etr_free_sysfs_buf(nd->sysfs_buf);
>> + raw_spin_lock_irqsave(&drvdata->spinlock, flags);
>> + drvdata->sysfs_buf = NULL;
>> + nd->sysfs_buf = NULL;
>> + list_del(&nd->link);
>> + kfree(nd);
>> + }
>> +}
>> +EXPORT_SYMBOL_GPL(tmc_clean_etr_buf_list);
>> +
>> +/**
>> + * tmc_create_etr_buf_list - create a list to manage the etr_buf_node.
>> + * @drvdata: driver data of the TMC device.
>> + * @num_nodes: number of nodes want to create with the list.
>> + *
>> + * Return 0 upon success and return the error number if fail.
>> + */
>> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes)
>> +{
>> + struct etr_buf_node *new_node;
>> + struct etr_buf *sysfs_buf;
>> + unsigned long flags;
>> + int i = 0, ret = 0;
>> +
>> + lockdep_assert_held(&drvdata->spinlock);
>> + /* We dont need a list if there is only one node */
>> + if (num_nodes < 2)
>> + return -EINVAL;
>> +
>> + /* We expect that sysfs_buf in drvdata has already been
>> allocated. */
>> + if (drvdata->sysfs_buf) {
>> + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> + /* Directly insert the allocated sysfs_buf into the list
>> first */
>> + new_node = kzalloc_obj(*new_node, GFP_KERNEL);
>> + if (IS_ERR(new_node))
>> + return PTR_ERR(new_node);
>> +
>> + raw_spin_lock_irqsave(&drvdata->spinlock, flags);
>> + new_node->sysfs_buf = drvdata->sysfs_buf;
>> + new_node->is_free = false;
>> + list_add(&new_node->link, &drvdata->etr_buf_list);
>> + i++;
>> + }
>> +
>> + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> + while (i < num_nodes) {
>> + new_node = kzalloc_obj(*new_node, GFP_KERNEL);
>> + if (IS_ERR(new_node)) {
>> + ret = PTR_ERR(new_node);
>> + break;
>> + }
>> +
>> + sysfs_buf = tmc_alloc_etr_buf(drvdata, drvdata->size, 0,
>> cpu_to_node(0), NULL);
>> + if (IS_ERR(sysfs_buf)) {
>> + kfree(new_node);
>> + ret = PTR_ERR(sysfs_buf);
>> + break;
>> + }
>> +
>> + /* We dont have a available sysfs_buf in drvdata, setup one */
>> + if (!drvdata->sysfs_buf) {
>> + drvdata->sysfs_buf = sysfs_buf;
>> + new_node->is_free = false;
>> + } else
>> + new_node->is_free = true;
>> +
>> + new_node->sysfs_buf = sysfs_buf;
>> + list_add(&new_node->link, &drvdata->etr_buf_list);
>> + i++;
>> + }
>> +
>> + /* Clean the list if there is an error */
>> + if (ret)
>> + tmc_clean_etr_buf_list(drvdata);
>> +
>> + raw_spin_lock_irqsave(&drvdata->spinlock, flags);
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(tmc_create_etr_buf_list);
>> +
>> int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
>> {
>> int ret = 0;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/
>> hwtracing/coresight/coresight-tmc.h
>> index 319a354ede9f..81237944b986 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc.h
>> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
>> @@ -208,6 +208,19 @@ struct tmc_resrv_buf {
>> s64 len;
>> };
>> +/**
>> + * @sysfs_buf: Allocated sysfs_buf.
>> + * @is_free: Indicates whether the buffer is free to choose.
>> + * @pos: Position of the buffer.
>> + * @link: list_head of the node.
>> + */
>> +struct etr_buf_node {
>> + struct etr_buf *sysfs_buf;
>> + bool is_free;
>> + loff_t pos;
>> + struct list_head link;
>> +};
>> +
>> /**
>> * struct tmc_drvdata - specifics associated to an TMC component
>> * @atclk: optional clock for the core parts of the TMC.
>> @@ -245,6 +258,7 @@ struct tmc_resrv_buf {
>> * (after crash) by default.
>> * @crash_mdata: Reserved memory for storing tmc crash metadata.
>> * Used by ETR/ETF.
>> + * @etr_buf_list: List that is used to manage allocated etr_buf.
>> */
>> struct tmc_drvdata {
>> struct clk *atclk;
>> @@ -275,6 +289,7 @@ struct tmc_drvdata {
>> struct etr_buf *perf_buf;
>> struct tmc_resrv_buf resrv_buf;
>> struct tmc_resrv_buf crash_mdata;
>> + struct list_head etr_buf_list;
>> };
>> struct etr_buf_operations {
>> @@ -447,5 +462,7 @@ struct etr_buf *tmc_etr_get_buffer(struct
>> coresight_device *csdev,
>> enum cs_mode mode,
>> struct coresight_path *path);
>> extern const struct attribute_group coresight_etr_group;
>> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata);
>> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes);
>> #endif
>>
>
>
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