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author | Suzuki K Poulose <suzuki.poulose@arm.com> | 2021-09-14 11:26:32 +0100 |
---|---|---|
committer | Mathieu Poirier <mathieu.poirier@linaro.org> | 2021-10-27 11:45:16 -0600 |
commit | 937d3f58cacf377cab7c32e475e1ffa91d611dce (patch) | |
tree | 9122fc9b2ca9fee22b8eb8291833ab5aefcf86a4 /drivers/hwtracing | |
parent | 8c60acbcb982bfff14d1e85094474671c4f3d006 (diff) | |
download | linux-937d3f58cacf377cab7c32e475e1ffa91d611dce.tar.gz linux-937d3f58cacf377cab7c32e475e1ffa91d611dce.tar.bz2 linux-937d3f58cacf377cab7c32e475e1ffa91d611dce.zip |
coresight: etm4x: Save restore TRFCR_EL1
When the CPU enters a low power mode, the TRFCR_EL1 contents could be
reset. Thus we need to save/restore the TRFCR_EL1 along with the ETM4x
registers to allow the tracing.
The TRFCR related helpers are in a new header file, as we need to use
them for TRBE in the later patches.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210914102641.1852544-2-suzuki.poulose@arm.com
[Fixed cosmetic details]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r-- | drivers/hwtracing/coresight/coresight-etm4x-core.c | 43 | ||||
-rw-r--r-- | drivers/hwtracing/coresight/coresight-etm4x.h | 2 | ||||
-rw-r--r-- | drivers/hwtracing/coresight/coresight-self-hosted-trace.h | 24 |
3 files changed, 57 insertions, 12 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index e24252eaf8e4..537c0d7ee1ed 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -40,6 +40,7 @@ #include "coresight-etm4x.h" #include "coresight-etm-perf.h" #include "coresight-etm4x-cfg.h" +#include "coresight-self-hosted-trace.h" #include "coresight-syscfg.h" static int boot_enable; @@ -1011,7 +1012,7 @@ static void cpu_enable_tracing(struct etmv4_drvdata *drvdata) if (is_kernel_in_hyp_mode()) trfcr |= TRFCR_EL2_CX; - write_sysreg_s(trfcr, SYS_TRFCR_EL1); + write_trfcr(trfcr); } static void etm4_init_arch_data(void *info) @@ -1554,7 +1555,7 @@ static void etm4_init_trace_id(struct etmv4_drvdata *drvdata) drvdata->trcid = coresight_get_trace_id(drvdata->cpu); } -static int etm4_cpu_save(struct etmv4_drvdata *drvdata) +static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) { int i, ret = 0; struct etmv4_save_state *state; @@ -1693,7 +1694,23 @@ out: return ret; } -static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) +static int etm4_cpu_save(struct etmv4_drvdata *drvdata) +{ + int ret = 0; + + /* Save the TRFCR irrespective of whether the ETM is ON */ + if (drvdata->trfc) + drvdata->save_trfcr = read_trfcr(); + /* + * Save and restore the ETM Trace registers only if + * the ETM is active. + */ + if (local_read(&drvdata->mode) && drvdata->save_state) + ret = __etm4_cpu_save(drvdata); + return ret; +} + +static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata) { int i; struct etmv4_save_state *state = drvdata->save_state; @@ -1789,6 +1806,14 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) etm4_cs_lock(drvdata, csa); } +static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) +{ + if (drvdata->trfc) + write_trfcr(drvdata->save_trfcr); + if (drvdata->state_needs_restore) + __etm4_cpu_restore(drvdata); +} + static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd, void *v) { @@ -1800,23 +1825,17 @@ static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd, drvdata = etmdrvdata[cpu]; - if (!drvdata->save_state) - return NOTIFY_OK; - if (WARN_ON_ONCE(drvdata->cpu != cpu)) return NOTIFY_BAD; switch (cmd) { case CPU_PM_ENTER: - /* save the state if self-hosted coresight is in use */ - if (local_read(&drvdata->mode)) - if (etm4_cpu_save(drvdata)) - return NOTIFY_BAD; + if (etm4_cpu_save(drvdata)) + return NOTIFY_BAD; break; case CPU_PM_EXIT: case CPU_PM_ENTER_FAILED: - if (drvdata->state_needs_restore) - etm4_cpu_restore(drvdata); + etm4_cpu_restore(drvdata); break; default: return NOTIFY_DONE; diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index e5b79bdb9851..82cba16b73a6 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -921,6 +921,7 @@ struct etmv4_save_state { * @lpoverride: If the implementation can support low-power state over. * @trfc: If the implementation supports Arm v8.4 trace filter controls. * @config: structure holding configuration parameters. + * @save_trfcr: Saved TRFCR_EL1 register during a CPU PM event. * @save_state: State to be preserved across power loss * @state_needs_restore: True when there is context to restore after PM exit * @skip_power_up: Indicates if an implementation can skip powering up @@ -973,6 +974,7 @@ struct etmv4_drvdata { bool lpoverride; bool trfc; struct etmv4_config config; + u64 save_trfcr; struct etmv4_save_state *save_state; bool state_needs_restore; bool skip_power_up; diff --git a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h new file mode 100644 index 000000000000..303d71911870 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Arm v8 Self-Hosted trace support. + * + * Copyright (C) 2021 ARM Ltd. + */ + +#ifndef __CORESIGHT_SELF_HOSTED_TRACE_H +#define __CORESIGHT_SELF_HOSTED_TRACE_H + +#include <asm/sysreg.h> + +static inline u64 read_trfcr(void) +{ + return read_sysreg_s(SYS_TRFCR_EL1); +} + +static inline void write_trfcr(u64 val) +{ + write_sysreg_s(val, SYS_TRFCR_EL1); + isb(); +} + +#endif /* __CORESIGHT_SELF_HOSTED_TRACE_H */ |