Re: [PATCH v3 09/15] coresight: etm4x: Cleanup TRCVICTLR register accesses

From: Mike Leach
Date: Tue Apr 12 2022 - 07:41:48 EST

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On Mon, 28 Mar 2022 at 11:41, James Clark <james.clark@xxxxxxx> wrote:
>
>
>
> On 23/03/2022 15:59, Mathieu Poirier wrote:
> > Hi James,
> >
> > On Fri, Mar 04, 2022 at 05:19:06PM +0000, James Clark wrote:
> >> This is a no-op change for style and consistency and has no effect on
> >> the binary output by the compiler. In sysreg.h fields are defined as
> >> the register name followed by the field name and then _MASK. This
> >> allows for grepping for fields by name rather than using magic numbers.
> >>
> >> Signed-off-by: James Clark <james.clark@xxxxxxx>
> >> ---
> >> .../coresight/coresight-etm4x-core.c | 10 +++---
> >> .../coresight/coresight-etm4x-sysfs.c | 36 +++++++++----------
> >> drivers/hwtracing/coresight/coresight-etm4x.h | 22 +++++-------
> >> 3 files changed, 31 insertions(+), 37 deletions(-)
> >>
> >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> >> index 445e2057d5ed..88353f8ba414 100644
> >> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> >> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> >> @@ -1206,7 +1206,7 @@ static void etm4_init_arch_data(void *info)
> >>
> >> static inline u32 etm4_get_victlr_access_type(struct etmv4_config *config)
> >> {
> >> - return etm4_get_access_type(config) << TRCVICTLR_EXLEVEL_SHIFT;
> >> + return etm4_get_access_type(config) << __bf_shf(TRCVICTLR_EXLEVEL_MASK);
> >> }
> >>
> >> /* Set ELx trace filter access in the TRCVICTLR register */
> >> @@ -1232,7 +1232,7 @@ static void etm4_set_default_config(struct etmv4_config *config)
> >> config->ts_ctrl = 0x0;
> >>
> >> /* TRCVICTLR::EVENT = 0x01, select the always on logic */
> >> - config->vinst_ctrl = BIT(0);
> >> + config->vinst_ctrl = FIELD_PREP(TRCVICTLR_EVENT_MASK, 0x01);
> >>
> >> /* TRCVICTLR::EXLEVEL_NS:EXLEVELS: Set kernel / user filtering */
> >> etm4_set_victlr_access(config);
> >> @@ -1341,7 +1341,7 @@ static void etm4_set_default_filter(struct etmv4_config *config)
> >> * TRCVICTLR::SSSTATUS == 1, the start-stop logic is
> >> * in the started state
> >> */
> >> - config->vinst_ctrl |= BIT(9);
> >> + config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
> >> config->mode |= ETM_MODE_VIEWINST_STARTSTOP;
> >>
> >> /* No start-stop filtering for ViewInst */
> >> @@ -1445,7 +1445,7 @@ static int etm4_set_event_filters(struct etmv4_drvdata *drvdata,
> >> * TRCVICTLR::SSSTATUS == 1, the start-stop logic is
> >> * in the started state
> >> */
> >> - config->vinst_ctrl |= BIT(9);
> >> + config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
> >>
> >> /* No start-stop filtering for ViewInst */
> >> config->vissctlr = 0x0;
> >> @@ -1473,7 +1473,7 @@ static int etm4_set_event_filters(struct etmv4_drvdata *drvdata,
> >> * etm4_disable_perf().
> >> */
> >> if (filters->ssstatus)
> >> - config->vinst_ctrl |= BIT(9);
> >> + config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
> >>
> >> /* No include/exclude filtering for ViewInst */
> >> config->viiectlr = 0x0;
> >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> >> index cd24590ea38a..b3b1b92909cc 100644
> >> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> >> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> >> @@ -206,11 +206,11 @@ static ssize_t reset_store(struct device *dev,
> >> * started state. ARM recommends start-stop logic is set before
> >> * each trace run.
> >> */
> >> - config->vinst_ctrl = BIT(0);
> >> + config->vinst_ctrl = FIELD_PREP(TRCVICTLR_EVENT_MASK, 0x01);
> >> if (drvdata->nr_addr_cmp > 0) {
> >> config->mode |= ETM_MODE_VIEWINST_STARTSTOP;
> >> /* SSSTATUS, bit[9] */
> >> - config->vinst_ctrl |= BIT(9);
> >> + config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
> >> }
> >>
> >> /* No address range filtering for ViewInst */
> >> @@ -416,22 +416,22 @@ static ssize_t mode_store(struct device *dev,
> >>
> >> /* bit[9] Start/stop logic control bit */
> >> if (config->mode & ETM_MODE_VIEWINST_STARTSTOP)
> >> - config->vinst_ctrl |= BIT(9);
> >> + config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
> >> else
> >> - config->vinst_ctrl &= ~BIT(9);
> >> + config->vinst_ctrl &= ~TRCVICTLR_SSSTATUS;
> >>
> >> /* bit[10], Whether a trace unit must trace a Reset exception */
> >> if (config->mode & ETM_MODE_TRACE_RESET)
> >> - config->vinst_ctrl |= BIT(10);
> >> + config->vinst_ctrl |= TRCVICTLR_TRCRESET;
> >> else
> >> - config->vinst_ctrl &= ~BIT(10);
> >> + config->vinst_ctrl &= ~TRCVICTLR_TRCRESET;
> >>
> >> /* bit[11], Whether a trace unit must trace a system error exception */
> >> if ((config->mode & ETM_MODE_TRACE_ERR) &&
> >> (drvdata->trc_error == true))
> >> - config->vinst_ctrl |= BIT(11);
> >> + config->vinst_ctrl |= TRCVICTLR_TRCERR;
> >> else
> >> - config->vinst_ctrl &= ~BIT(11);
> >> + config->vinst_ctrl &= ~TRCVICTLR_TRCERR;
> >>
> >> if (config->mode & (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER))
> >> etm4_config_trace_mode(config);
> >> @@ -723,7 +723,7 @@ static ssize_t event_vinst_show(struct device *dev,
> >> struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >> struct etmv4_config *config = &drvdata->config;
> >>
> >> - val = config->vinst_ctrl & ETMv4_EVENT_MASK;
> >> + val = FIELD_GET(TRCVICTLR_EVENT_MASK, config->vinst_ctrl);
> >> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> >> }
> >>
> >> @@ -739,9 +739,9 @@ static ssize_t event_vinst_store(struct device *dev,
> >> return -EINVAL;
> >>
> >> spin_lock(&drvdata->spinlock);
> >> - val &= ETMv4_EVENT_MASK;
> >> - config->vinst_ctrl &= ~ETMv4_EVENT_MASK;
> >> - config->vinst_ctrl |= val;
> >> + val &= TRCVICTLR_EVENT_MASK >> __bf_shf(TRCVICTLR_EVENT_MASK);
> >
> > Not sure why the right-shifting operation is needed since the mask starts at bit
> > 0. Please consider fixing _if_ you end up respinning this.
>
> Yes you're right it doesn't need shifting. I suppose I did it that way so that when
> reading the code it's obvious that 'val' is a value starting at bit 0, rather than
> the original state of the register shifted to some arbitrary position.
>
> Someone reading the code wouldn't know that TRCVICTLR_EVENT_MASK starts at 0,
> so without the explicit shift they might think excluding it was a mistake. It also
> makes it consistent with other uses of masks that don't start at 0.
>
> James
>
> >
> > Thanks,
> > Mathieu
> >
> >> + config->vinst_ctrl &= ~TRCVICTLR_EVENT_MASK;
> >> + config->vinst_ctrl |= FIELD_PREP(TRCVICTLR_EVENT_MASK, val);
> >> spin_unlock(&drvdata->spinlock);
> >> return size;
> >> }
> >> @@ -755,7 +755,7 @@ static ssize_t s_exlevel_vinst_show(struct device *dev,
> >> struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >> struct etmv4_config *config = &drvdata->config;
> >>
> >> - val = (config->vinst_ctrl & TRCVICTLR_EXLEVEL_S_MASK) >> TRCVICTLR_EXLEVEL_S_SHIFT;
> >> + val = FIELD_GET(TRCVICTLR_EXLEVEL_S_MASK, config->vinst_ctrl);
> >> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> >> }
> >>
> >> @@ -772,10 +772,10 @@ static ssize_t s_exlevel_vinst_store(struct device *dev,
> >>
> >> spin_lock(&drvdata->spinlock);
> >> /* clear all EXLEVEL_S bits */
> >> - config->vinst_ctrl &= ~(TRCVICTLR_EXLEVEL_S_MASK);
> >> + config->vinst_ctrl &= ~TRCVICTLR_EXLEVEL_S_MASK;
> >> /* enable instruction tracing for corresponding exception level */
> >> val &= drvdata->s_ex_level;
> >> - config->vinst_ctrl |= (val << TRCVICTLR_EXLEVEL_S_SHIFT);
> >> + config->vinst_ctrl |= val << __bf_shf(TRCVICTLR_EXLEVEL_S_MASK);
> >> spin_unlock(&drvdata->spinlock);
> >> return size;
> >> }
> >> @@ -790,7 +790,7 @@ static ssize_t ns_exlevel_vinst_show(struct device *dev,
> >> struct etmv4_config *config = &drvdata->config;
> >>
> >> /* EXLEVEL_NS, bits[23:20] */
> >> - val = (config->vinst_ctrl & TRCVICTLR_EXLEVEL_NS_MASK) >> TRCVICTLR_EXLEVEL_NS_SHIFT;
> >> + val = FIELD_GET(TRCVICTLR_EXLEVEL_NS_MASK, config->vinst_ctrl);
> >> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> >> }
> >>
> >> @@ -807,10 +807,10 @@ static ssize_t ns_exlevel_vinst_store(struct device *dev,
> >>
> >> spin_lock(&drvdata->spinlock);
> >> /* clear EXLEVEL_NS bits */
> >> - config->vinst_ctrl &= ~(TRCVICTLR_EXLEVEL_NS_MASK);
> >> + config->vinst_ctrl &= ~TRCVICTLR_EXLEVEL_NS_MASK;
> >> /* enable instruction tracing for corresponding exception level */
> >> val &= drvdata->ns_ex_level;
> >> - config->vinst_ctrl |= (val << TRCVICTLR_EXLEVEL_NS_SHIFT);
> >> + config->vinst_ctrl |= val << __bf_shf(TRCVICTLR_EXLEVEL_NS_MASK);
> >> spin_unlock(&drvdata->spinlock);
> >> return size;
> >> }
> >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> >> index 36934056a5dc..9cacc38b1890 100644
> >> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> >> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> >> @@ -200,6 +200,14 @@
> >> #define TRCSTALLCTLR_INSTPRIORITY BIT(10)
> >> #define TRCSTALLCTLR_NOOVERFLOW BIT(13)
> >>
> >> +#define TRCVICTLR_EVENT_MASK GENMASK(7, 0)
> >> +#define TRCVICTLR_SSSTATUS BIT(9)
> >> +#define TRCVICTLR_TRCRESET BIT(10)
> >> +#define TRCVICTLR_TRCERR BIT(11)
> >> +#define TRCVICTLR_EXLEVEL_MASK GENMASK(22, 16)
> >> +#define TRCVICTLR_EXLEVEL_S_MASK GENMASK(19, 16)
> >> +#define TRCVICTLR_EXLEVEL_NS_MASK GENMASK(22, 20)
> >> +
> >> /*
> >> * System instructions to access ETM registers.
> >> * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions
> >> @@ -700,23 +708,9 @@
> >> #define ETM_EXLEVEL_NS_OS BIT(5) /* NonSecure EL1 */
> >> #define ETM_EXLEVEL_NS_HYP BIT(6) /* NonSecure EL2 */
> >>
> >> -#define ETM_EXLEVEL_MASK (GENMASK(6, 0))
> >> -#define ETM_EXLEVEL_S_MASK (GENMASK(3, 0))
> >> -#define ETM_EXLEVEL_NS_MASK (GENMASK(6, 4))
> >> -
> >> /* access level controls in TRCACATRn */
> >> #define TRCACATR_EXLEVEL_SHIFT 8
> >>
> >> -/* access level control in TRCVICTLR */
> >> -#define TRCVICTLR_EXLEVEL_SHIFT 16
> >> -#define TRCVICTLR_EXLEVEL_S_SHIFT 16
> >> -#define TRCVICTLR_EXLEVEL_NS_SHIFT 20
> >> -
> >> -/* secure / non secure masks - TRCVICTLR, IDR3 */
> >> -#define TRCVICTLR_EXLEVEL_MASK (ETM_EXLEVEL_MASK << TRCVICTLR_EXLEVEL_SHIFT)
> >> -#define TRCVICTLR_EXLEVEL_S_MASK (ETM_EXLEVEL_S_MASK << TRCVICTLR_EXLEVEL_SHIFT)
> >> -#define TRCVICTLR_EXLEVEL_NS_MASK (ETM_EXLEVEL_NS_MASK << TRCVICTLR_EXLEVEL_SHIFT)
> >> -
> >> #define ETM_TRCIDR1_ARCH_MAJOR_SHIFT 8
> >> #define ETM_TRCIDR1_ARCH_MAJOR_MASK (0xfU << ETM_TRCIDR1_ARCH_MAJOR_SHIFT)
> >> #define ETM_TRCIDR1_ARCH_MAJOR(x) \
> >> --
> >> 2.28.0
> >>

Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>

--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

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