coresight: trbe: Fix TRBE potential sleep in atomic context

smp_call_function_single() will allocate an IPI interrupt vector to
the target processor and send a function call request to the interrupt
vector. After the target processor receives the IPI interrupt, it will
execute arm_trbe_remove_coresight_cpu() call request in the interrupt
handler.

According to the device_unregister() stack information, if other process
is useing the device, the down_write() may sleep, and trigger deadlocks
or unexpected errors.

  arm_trbe_remove_coresight_cpu
    coresight_unregister
      device_unregister
        device_del
          kobject_del
            __kobject_del
              sysfs_remove_dir
                kernfs_remove
                  down_write ---------> it may sleep

Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
per TRBE.
Simply call arm_trbe_remove_coresight_cpu() directly without useing the
smp_call_function_single(), which is the same as registering the TRBE
coresight device.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Link: https://lore.kernel.org/r/20230814093813.19152-2-hejunhao3@huawei.com
[ Remove duplicate cpumask checks during removal ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[ v3 - Remove the operation of assigning NULL to cpudata->drvdata ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230818084052.10116-1-hejunhao3@huawei.com

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 8e4eb37..e20c1c6 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1225,6 +1225,16 @@ static void arm_trbe_enable_cpu(void *info)
        enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
 }
 
+static void arm_trbe_disable_cpu(void *info)
+{
+       struct trbe_drvdata *drvdata = info;
+       struct trbe_cpudata *cpudata = this_cpu_ptr(drvdata->cpudata);
+
+       disable_percpu_irq(drvdata->irq);
+       trbe_reset_local(cpudata);
+}
+
+
 static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
 {
        struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
@@ -1329,18 +1339,12 @@ cpu_clear:
        cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
 }
 
-static void arm_trbe_remove_coresight_cpu(void *info)
+static void arm_trbe_remove_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
 {
-       int cpu = smp_processor_id();
-       struct trbe_drvdata *drvdata = info;
-       struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
        struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
 
-       disable_percpu_irq(drvdata->irq);
-       trbe_reset_local(cpudata);
        if (trbe_csdev) {
                coresight_unregister(trbe_csdev);
-               cpudata->drvdata = NULL;
                coresight_set_percpu_sink(cpu, NULL);
        }
 }
@@ -1369,8 +1373,10 @@ static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
 {
        int cpu;
 
-       for_each_cpu(cpu, &drvdata->supported_cpus)
-               smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
+       for_each_cpu(cpu, &drvdata->supported_cpus) {
+               smp_call_function_single(cpu, arm_trbe_disable_cpu, drvdata, 1);
+               arm_trbe_remove_coresight_cpu(drvdata, cpu);
+       }
        free_percpu(drvdata->cpudata);
        return 0;
 }
@@ -1409,12 +1415,8 @@ static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
 {
        struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
 
-       if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
-               struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
-
-               disable_percpu_irq(drvdata->irq);
-               trbe_reset_local(cpudata);
-       }
+       if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
+               arm_trbe_disable_cpu(drvdata);
        return 0;
 }