To avoid mixup of packets from differnt ftrace packets simultaneously, use different channel for packets from different CPU.
Signed-off-by: Tingwei Zhang tingwei@codeaurora.org Reviewed-by: Steven Rostedt (VMware) rostedt@goodmis.org --- 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..ebf29489919c 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 = num_possible_cpus(); ret = stm_source_register_device(NULL, &stm_ftrace.data); if (ret) pr_err("Failed to register stm_source - ftrace.\n");