diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-tmc-etr.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-tmc-etr.c | 43 |
1 files changed, 22 insertions, 21 deletions
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index e0d83ee01b77..cee82e52c4ea 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1307,6 +1307,19 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev) raw_spin_lock_irqsave(&drvdata->spinlock, flags); /* + * Since the sysfs buffer allocation and the hardware enablement is not + * in the same critical region, it's possible to race with the perf. + */ + if (coresight_get_mode(csdev) == CS_MODE_PERF) { + drvdata->sysfs_buf = NULL; + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); + + /* Free allocated memory out side of the spinlock */ + tmc_etr_free_sysfs_buf(sysfs_buf); + return -EBUSY; + } + + /* * In sysFS mode we can have multiple writers per sink. Since this * sink is already enabled no memory is needed and the HW need not be * touched, even if the buffer size has changed. @@ -1354,9 +1367,7 @@ EXPORT_SYMBOL_GPL(tmc_etr_get_buffer); /* * alloc_etr_buf: Allocate ETR buffer for use by perf. - * The size of the hardware buffer is dependent on the size configured - * via sysfs and the perf ring buffer size. We prefer to allocate the - * largest possible size, scaling down the size by half until it + * Allocate the largest possible size, scaling down the size by half until it * reaches a minimum limit (1M), beyond which we give up. */ static struct etr_buf * @@ -1365,36 +1376,26 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, { int node; struct etr_buf *etr_buf; - unsigned long size; + ssize_t size; node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); - /* - * Try to match the perf ring buffer size if it is larger - * than the size requested via sysfs. - */ - if ((nr_pages << PAGE_SHIFT) > drvdata->size) { - etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT), - 0, node, NULL); - if (!IS_ERR(etr_buf)) - goto done; - } + + /* Use the minimum limit if the required size is smaller */ + size = nr_pages << PAGE_SHIFT; + size = max_t(ssize_t, size, TMC_ETR_PERF_MIN_BUF_SIZE); /* - * Else switch to configured size for this ETR - * and scale down until we hit the minimum limit. + * Try to allocate the required size for this ETR, if failed scale + * down until we hit the minimum limit. */ - size = drvdata->size; do { etr_buf = tmc_alloc_etr_buf(drvdata, size, 0, node, NULL); if (!IS_ERR(etr_buf)) - goto done; + return etr_buf; size /= 2; } while (size >= TMC_ETR_PERF_MIN_BUF_SIZE); return ERR_PTR(-ENOMEM); - -done: - return etr_buf; } static struct etr_buf * |