From 344b01778e6875b2d3caba378a6d02b7f3dfad1b Mon Sep 17 00:00:00 2001 From: Tingwei Zhang Date: Sat, 18 Jul 2020 14:39:53 +0800 Subject: [PATCH] FROMLIST: stm class: ftrace: use different channel accroding to CPU To avoid mixup of packets from differnt ftrace packets simultaneously, use different channel for packets from different CPU. Bug: 160464759 Link: https://lore.kernel.org/patchwork/cover/1280618/ Signed-off-by: Tingwei Zhang Reviewed-by: Steven Rostedt (VMware) Change-Id: I5e0afe8e6fb60f73c4ce3165b80db38e60f82031 --- 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");