From 338a588e9db3c5ea7a35bb332cb3bdb532fd1f08 Mon Sep 17 00:00:00 2001 From: Mike Leach Date: Mon, 16 Jan 2023 12:49:14 +0000 Subject: coresight: trace-id: Add API to dynamically assign Trace ID values The existing mechanism to assign Trace ID values to sources is limited and does not scale for larger multicore / multi trace source systems. The API introduces functions that reserve IDs based on availabilty represented by a coresight_trace_id_map structure. This records the used and free IDs in a bitmap. CPU bound sources such as ETMs use the coresight_trace_id_get_cpu_id coresight_trace_id_put_cpu_id pair of functions. The API will record the ID associated with the CPU. This ensures that the same ID will be re-used while perf events are active on the CPU. The put_cpu_id function will pend release of the ID until all perf cs_etm sessions are complete. For backward compatibility the functions will attempt to use the same CPU IDs as the legacy system would have used if these are still available. Non-cpu sources, such as the STM can use coresight_trace_id_get_system_id / coresight_trace_id_put_system_id. Signed-off-by: Mike Leach [ Fix checkpatch warning in drivers/hwtracing/coresight/coresight-trace-id.c ] Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20230116124928.5440-2-mike.leach@linaro.org --- include/linux/coresight-pmu.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux') diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h index 6c2fd6cc5a98..ffff4e6277e5 100644 --- a/include/linux/coresight-pmu.h +++ b/include/linux/coresight-pmu.h @@ -10,6 +10,16 @@ #define CORESIGHT_ETM_PMU_NAME "cs_etm" #define CORESIGHT_ETM_PMU_SEED 0x10 +/* + * The legacy Trace ID system based on fixed calculation from the cpu + * number. This has been replaced by drivers using a dynamic allocation + * system - but need to retain the legacy algorithm for backward comparibility + * in certain situations:- + * a) new perf running on older systems that generate the legacy mapping + * b) older tools that may not update at the same time as the kernel. + */ +#define CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) (0x10 + (cpu * 2)) + /* * Below are the definition of bit offsets for perf option, and works as * arbitrary values for all ETM versions. -- cgit v1.2.3