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

Mathieu Poirier
2022-03-23T15:59:21Z

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@arm.com>
> ---
> .../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.

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
>