To avoid mixup of packets from differnt ftrace packets simultaneously,
use different channel for packets from different CPU.
Signed-off-by: Tingwei Zhang <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
---
drivers/hwtracing/stm/ftrace.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/stm/ftrace.c b/drivers/hwtracing/stm/ftrace.c
index c694a6e692d1..3bb606dfa634 100644
--- a/drivers/hwtracing/stm/ftrace.c
+++ b/drivers/hwtracing/stm/ftrace.c
@@ -37,8 +37,10 @@ static void notrace
stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int len)
{
struct stm_ftrace *stm = container_of(export, struct stm_ftrace, ftrace);
+ /* This is called from trace system with preemption disabled */
+ unsigned int cpu = smp_processor_id();
- stm_source_write(&stm->data, STM_FTRACE_CHAN, buf, len);
+ stm_source_write(&stm->data, STM_FTRACE_CHAN + cpu, buf, len);
}
static int stm_ftrace_link(struct stm_source_data *data)
@@ -63,6 +65,7 @@ static int __init stm_ftrace_init(void)
{
int ret;
+ stm_ftrace.data.nr_chans = roundup_pow_of_two(num_possible_cpus());
ret = stm_source_register_device(NULL, &stm_ftrace.data);
if (ret)
pr_err("Failed to register stm_source - ftrace.\n");
--
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