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BACKPORT: coresight: etm4x: Save restore TRFCR_EL1

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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.

Bug: 213931796
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>
(cherry picked from commit 937d3f58cacf377cab7c32e475e1ffa91d611dce)
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
[Conflict in in drivers/hwtracing/coresight/coresight-etm4x-core.c,
unnecessary new includes were removed]
Change-Id: Id81d9505e86664c09ec6876e48c4e9c2d945503e
This commit is contained in:
Suzuki K Poulose
2021-09-14 11:26:32 +01:00
committed by Todd Kjos
parent 79b64fa780
commit 2bb8b3c907
3 changed files with 57 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/hwtracing/coresight/coresight-etm4x-core.c
View File

@@ -39,6 +39,7 @@
#include "coresight-etm4x.h"
#include "coresight-etm-perf.h"
#include "coresight-self-hosted-trace.h"
static int boot_enable;
module_param(boot_enable, int, 0444);
@@ -990,7 +991,7 @@ 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)
@@ -1528,7 +1529,7 @@ 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;
@@ -1667,7 +1668,23 @@ 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;
@@ -1763,6 +1780,14 @@ 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)
{
@@ -1774,22 +1799,16 @@ 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;
break;
case CPU_PM_EXIT:
case CPU_PM_ENTER_FAILED:
if (drvdata->state_needs_restore)
etm4_cpu_restore(drvdata);
break;
default:

2
drivers/hwtracing/coresight/coresight-etm4x.h
View File

@@ -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;

24
drivers/hwtracing/coresight/coresight-self-hosted-trace.h Normal file
View File

@@ -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 */