[PATCH 11/19] coresight: etm4x: Check for OS and Software Lock
Mike Leach
mike.leach at linaro.org
Fri Sep 18 11:35:03 EDT 2020
Hi Suzuki
On Fri, 11 Sep 2020 at 09:41, Suzuki K Poulose <suzuki.poulose at arm.com> wrote:
>
> An ETM instance may not implement the OS/Software Lock. This
> is advertised via TRCOSLSR/TRCLSR respectively. Detect the
> presence of these lock registers and skip the lock/unlock
> if they are not implemented.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> ---
> drivers/hwtracing/coresight/coresight-etm4x.c | 77 +++++++++++++++----
> drivers/hwtracing/coresight/coresight-etm4x.h | 24 +++++-
> 2 files changed, 83 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
> index 34b27c26591b..7feb57108bdc 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -95,12 +95,19 @@ void etm4x_sysreg_write(struct csdev_access *csa,
> }
> }
>
> +static inline bool etm4_os_lock_implemented(struct etmv4_drvdata *drvdata)
> +{
> + return drvdata->os_lock_model == ETM_OS_LOCK_IMPLEMENTED;
> +}
> +
> static void etm4_os_unlock_csa(struct etmv4_drvdata *drvdata, struct csdev_access *csa)
> {
> - /* Writing 0 to TRCOSLAR unlocks the trace registers */
> - etm4x_relaxed_write32(csa, 0x0, TRCOSLAR);
> + if (etm4_os_lock_implemented(drvdata)) {
> + /* Writing 0 to TRCOSLAR unlocks the trace registers */
> + etm4x_relaxed_write32(csa, 0x0, TRCOSLAR);
> + isb();
> + }
> drvdata->os_unlock = true;
> - isb();
> }
>
> static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
> @@ -115,10 +122,26 @@ static void etm4_os_lock(struct etmv4_drvdata *drvdata)
> if (WARN_ON(!drvdata->csdev))
> return;
>
> - /* Writing 0x1 to TRCOSLAR locks the trace registers */
> - etm4x_relaxed_write32(&drvdata->csdev->access, 0x1, TRCOSLAR);
> + if (etm4_os_lock_implemented(drvdata)) {
> + /* Writing 0x1 to TRCOSLAR locks the trace registers */
> + etm4x_relaxed_write32(&drvdata->csdev->access, 0x1, TRCOSLAR);
> + isb();
> + }
> drvdata->os_unlock = false;
> - isb();
> +}
> +
> +static void etm4_cs_lock(struct etmv4_drvdata *drvdata,
> + struct csdev_access *csa)
> +{
> + if (drvdata->sw_lock)
> + CS_LOCK(csa);
> +}
> +
> +static void etm4_cs_unlock(struct etmv4_drvdata *drvdata,
> + struct csdev_access *csa)
> +{
> + if (drvdata->sw_lock)
> + CS_UNLOCK(csa);
> }
>
> static bool etm4_arch_supported(u8 arch)
> @@ -160,7 +183,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
> struct device *etm_dev = &csdev->dev;
> struct csdev_access *csa = &csdev->access;
>
> - CS_UNLOCK(csa);
> + etm4_cs_unlock(drvdata, csa);
>
> etm4_os_unlock(drvdata);
>
> @@ -258,7 +281,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
> isb();
>
> done:
> - CS_LOCK(csa);
> + etm4_cs_lock(drvdata, csa);
>
> dev_dbg(etm_dev, "cpu: %d enable smp call done: %d\n",
> drvdata->cpu, rc);
> @@ -515,7 +538,7 @@ static void etm4_disable_hw(void *info)
> struct csdev_access *csa = &csdev->access;
> int i;
>
> - CS_UNLOCK(csa);
> + etm4_cs_unlock(drvdata, csa);
>
> if (!drvdata->skip_power_up) {
> /* power can be removed from the trace unit now */
> @@ -557,7 +580,7 @@ static void etm4_disable_hw(void *info)
>
> coresight_disclaim_device_unlocked(csdev);
>
> - CS_LOCK(csa);
> + etm4_cs_lock(drvdata, csa);
>
> dev_dbg(&drvdata->csdev->dev,
> "cpu: %d disable smp call done\n", drvdata->cpu);
> @@ -652,6 +675,20 @@ static const struct coresight_ops etm4_cs_ops = {
> .source_ops = &etm4_source_ops,
> };
>
> +/*
> + * ETM may or may not implement the Software Lock and the OS Lock.
> + * Detect this before we attempt to do any locking.
> + */
> +static void etm_detect_lock_status(struct etmv4_drvdata *drvdata,
> + struct csdev_access *csa)
> +{
> + u32 sw_lsr = etm4x_relaxed_read32(csa, TRCLSR);
7.3.48 - ETMv4.5 spec -> TRCLSR accessible only from the memory mapped
interface.
> + u32 os_lsr = etm4x_relaxed_read32(csa, TRCOSLSR);
This is unneeded. 7.3.50 of the ETM4.5 spec says for OS lock bits
"always 0b10 for Armv8-A/R, Armv7-A/R,". So always implemented.
> +
> + drvdata->sw_lock = TRCLSR_SLI(sw_lsr);
> + drvdata->os_lock_model = TRCOSLSR_OSM(os_lsr);
> +}
> +
> static void etm4_init_arch_data(void *info)
> {
> u32 etmidr0;
> @@ -664,10 +701,15 @@ static void etm4_init_arch_data(void *info)
> int i;
> struct csdev_access csa = CSDEV_ACCESS_IOMEM(drvdata->base);
>
> + /*
> + * We must check if the locks are implemented
> + * as early as possible.
> + */
> + etm_detect_lock_status(drvdata, &csa);
> +
> /* Make sure all registers are accessible */
> etm4_os_unlock_csa(drvdata, &csa);
> -
> - CS_UNLOCK(&csa);
> + etm4_cs_unlock(drvdata, &csa);
>
> /* find all capabilities of the tracing unit */
> etmidr0 = etm4x_relaxed_read32(&csa, TRCIDR0);
> @@ -821,7 +863,8 @@ static void etm4_init_arch_data(void *info)
> drvdata->nrseqstate = BMVAL(etmidr5, 25, 27);
> /* NUMCNTR, bits[30:28] number of counters available for tracing */
> drvdata->nr_cntr = BMVAL(etmidr5, 28, 30);
> - CS_LOCK(&csa);
> +
> + etm4_cs_lock(drvdata, &csa);
> }
>
> /* Set ELx trace filter access in the TRCVICTLR register */
> @@ -1202,7 +1245,7 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
> dsb(sy);
> isb();
>
> - CS_UNLOCK(csa);
> + etm4_cs_unlock(drvdata, csa);
>
> /* Lock the OS lock to disable trace and external debugger access */
> etm4_os_lock(drvdata);
> @@ -1309,7 +1352,7 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
> etm4x_relaxed_write32(csa, (state->trcpdcr & ~TRCPDCR_PU), TRCPDCR);
>
> out:
> - CS_LOCK(csa);
> + etm4_cs_lock(drvdata, csa);
> return ret;
> }
>
> @@ -1324,7 +1367,7 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
> return;
>
> csa = &csdev->access;
> - CS_UNLOCK(csa);
> + etm4_cs_unlock(drvdata, csa);
>
> etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);
>
> @@ -1404,7 +1447,7 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
>
> /* Unlock the OS lock to re-enable trace and external debug access */
> etm4_os_unlock(drvdata);
> - CS_LOCK(csa);
> + etm4_cs_lock(drvdata, csa);
> }
>
> static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 29ffad6a5279..efd903688edd 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -417,7 +417,7 @@
> if ((csa)->io_mem) \
> writel_relaxed((val), (csa)->base + (offset)); \
> else \
> - write_etm4x_sysreg_offset((csa), (val), \
> + write_etm4x_sysreg_offset((csa), (val), \
> (offset), false); \
> } while (0)
>
> @@ -541,6 +541,22 @@
> /* NS MON (EL3) mode never implemented */
> #define ETM_EXLEVEL_NS_VICTLR_MASK GENMASK(22, 20)
>
> +/*
> + * TRCOSLSR.OSM - Bit[3,0]
> + *
> + * 0b00 - Trace OS Lock is not implemented.
> + * 0b10 - Trace OS Lock is implemented.
> + */
> +#define TRCOSLSR_OSM(x) ((((x) & BIT(3)) >> 2) | ((x) & BIT(0)))
> +#define ETM_OS_LOCK_IMPLEMENTED 0b10
> +
As per my comment above - can be dropped as always implemented.
> +/*
> + * TRCLSR.SLI - Bit[0]
> + * 0b0 - Software Lock is not implemented.
> + * 0b1 - Software Lock is implmented.
> + */
> +#define TRCLSR_SLI(x) ((x) & BIT(0))
> +
> /**
> * struct etmv4_config - configuration information related to an ETMv4
> * @mode: Controls various modes supported by this ETM.
> @@ -726,6 +742,10 @@ struct etmv4_save_state {
> * supported for the corresponding Exception level.
> * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
> * supported for the corresponding Exception level.
> + * @sw_lock: Cached value of TRCLSR.SLI, tells you whether the software lock
> + * is implemented.
> + * @os_lock_model: Cached value of TRCOSLSR.OSM, tells you whether OS lock
> + * is implemented.
> * @sticky_enable: true if ETM base configuration has been done.
> * @boot_enable:True if we should start tracing at boot time.
> * @os_unlock: True if access to management registers is allowed.
> @@ -782,6 +802,8 @@ struct etmv4_drvdata {
> u8 s_ex_level;
> u8 ns_ex_level;
> u8 q_support;
> + u8 sw_lock;
> + u8 os_lock_model;
> bool sticky_enable;
> bool boot_enable;
> bool os_unlock;
> --
> 2.24.1
>
Regards
Mike
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
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