linux-stable/include/linux/coresight-pmu.h
Mike Leach 338a588e9d 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 <mike.leach@linaro.org>
[ Fix checkpatch warning in drivers/hwtracing/coresight/coresight-trace-id.c ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230116124928.5440-2-mike.leach@linaro.org
2023-01-19 10:16:46 +00:00

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1.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright(C) 2015 Linaro Limited. All rights reserved.
* Author: Mathieu Poirier <mathieu.poirier@linaro.org>
*/
#ifndef _LINUX_CORESIGHT_PMU_H
#define _LINUX_CORESIGHT_PMU_H
#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 This has been replaced by drivers using a dynamic allocation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.
*
* Most of them are orignally from ETMv3.5/PTM's ETMCR config, therefore,
* ETMv3.5/PTM doesn't define ETMCR config bits with prefix "ETM3_" and
* directly use below macros as config bits.
*/
#define ETM_OPT_BRANCH_BROADCAST 8
#define ETM_OPT_CYCACC 12
#define ETM_OPT_CTXTID 14
#define ETM_OPT_CTXTID2 15
#define ETM_OPT_TS 28
#define ETM_OPT_RETSTK 29
/* ETMv4 CONFIGR programming bits for the ETM OPTs */
#define ETM4_CFG_BIT_BB 3
#define ETM4_CFG_BIT_CYCACC 4
#define ETM4_CFG_BIT_CTXTID 6
#define ETM4_CFG_BIT_VMID 7
#define ETM4_CFG_BIT_TS 11
#define ETM4_CFG_BIT_RETSTK 12
#define ETM4_CFG_BIT_VMID_OPT 15
static inline int coresight_get_trace_id(int cpu)
{
/*
* A trace ID of value 0 is invalid, so let's start at some
* random value that fits in 7 bits and go from there. Since
* the common convention is to have data trace IDs be I(N) + 1,
* set instruction trace IDs as a function of the CPU number.
*/
return (CORESIGHT_ETM_PMU_SEED + (cpu * 2));
}
#endif