Re: [PATCH v3 18/26] coresight: etm4x: Clean up exception level masks

Mathieu Poirier
2020-11-06T18:52:48Z

Good morning,

On Wed, Oct 28, 2020 at 10:09:37PM +0000, Suzuki K Poulose wrote:
> etm4_get_access_type() calculates the exception level bits
> for use in address comparator registers. This is also used
> by the TRCVICTLR register by shifting to the required position.
>
> This patch cleans up the logic to make etm4_get_access_type()
> calcualte a generic mask which can be used by all users by
> shifting to their field.
>
> No functional changes, only code cleanups.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> Changes since previous version:
> - Fix the duplicate shift. More commentary
> ---
> .../coresight/coresight-etm4x-core.c | 47 +++++++++----------
> .../coresight/coresight-etm4x-sysfs.c | 12 ++---
> drivers/hwtracing/coresight/coresight-etm4x.h | 46 +++++++++++-------
> 3 files changed, 59 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 6e3f9cb7de3f..f038bb10bc78 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -852,20 +852,16 @@ static void etm4_init_arch_data(void *info)
> etm4_cs_lock(drvdata, csa);
> }
>
> +static inline u32 etm4_get_victlr_access_type(struct etmv4_config *config)
> +{
> + return etm4_get_access_type(config) << TRCVICTLR_EXLEVEL_SHIFT;
> +}
> +
> /* Set ELx trace filter access in the TRCVICTLR register */
> static void etm4_set_victlr_access(struct etmv4_config *config)
> {
> - u64 access_type;
> -
> - config->vinst_ctrl &= ~(ETM_EXLEVEL_S_VICTLR_MASK | ETM_EXLEVEL_NS_VICTLR_MASK);
> -
> - /*
> - * TRCVICTLR::EXLEVEL_NS:EXLEVELS: Set kernel / user filtering
> - * bits in vinst_ctrl, same bit pattern as TRCACATRn values returned by
> - * etm4_get_access_type() but with a relative shift in this register.
> - */
> - access_type = etm4_get_access_type(config) << ETM_EXLEVEL_LSHIFT_TRCVICTLR;
> - config->vinst_ctrl |= (u32)access_type;
> + config->vinst_ctrl &= ~(TRCVICTLR_EXLEVEL_S_MASK | TRCVICTLR_EXLEVEL_NS_MASK);
> + config->vinst_ctrl |= etm4_get_victlr_access_type(config);
> }
>
> static void etm4_set_default_config(struct etmv4_config *config)
> @@ -895,12 +891,9 @@ static u64 etm4_get_ns_access_type(struct etmv4_config *config)
> u64 access_type = 0;
>
> /*
> - * EXLEVEL_NS, bits[15:12]
> - * The Exception levels are:
> - * Bit[12] Exception level 0 - Application
> - * Bit[13] Exception level 1 - OS
> - * Bit[14] Exception level 2 - Hypervisor
> - * Bit[15] Never implemented
> + * EXLEVEL_NS, for NonSecure Exception levels.
> + * The mask here is a generic value and must be
> + * shifted to the corresponding field for the registers
> */
> if (!is_kernel_in_hyp_mode()) {
> /* Stay away from hypervisor mode for non-VHE */
> @@ -917,20 +910,26 @@ static u64 etm4_get_ns_access_type(struct etmv4_config *config)
> return access_type;
> }
>
> +/*
> + * Construct the exception level masks for a given config.
> + * This must be shifted to the corresponding register field
> + * for usage.
> + */
> static u64 etm4_get_access_type(struct etmv4_config *config)
> {
> - u64 access_type = etm4_get_ns_access_type(config);
> -
> - /* All supported secure ELs are excluded */
> - access_type |= (u64)config->s_ex_level << TRCACATR_EXLEVEL_SHIFT;
> + /* All Secure exception levels are excluded from the trace */
> + return etm4_get_ns_access_type(config) | (u64)config->s_ex_level;
> +}
>
> - return access_type;
> +static u64 etm4_get_comparator_access_type(struct etmv4_config *config)
> +{
> + return etm4_get_access_type(config) << TRCACATR_EXLEVEL_SHIFT;
> }
>
> static void etm4_set_comparator_filter(struct etmv4_config *config,
> u64 start, u64 stop, int comparator)
> {
> - u64 access_type = etm4_get_access_type(config);
> + u64 access_type = etm4_get_comparator_access_type(config);
>
> /* First half of default address comparator */
> config->addr_val[comparator] = start;
> @@ -965,7 +964,7 @@ static void etm4_set_start_stop_filter(struct etmv4_config *config,
> enum etm_addr_type type)
> {
> int shift;
> - u64 access_type = etm4_get_access_type(config);
> + u64 access_type = etm4_get_comparator_access_type(config);
>
> /* Configure the comparator */
> config->addr_val[comparator] = address;
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index fce9df16bfb5..009818675928 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -743,7 +743,7 @@ 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 & ETM_EXLEVEL_S_VICTLR_MASK) >> 16;
> + val = (config->vinst_ctrl & TRCVICTLR_EXLEVEL_S_MASK) >> TRCVICTLR_EXLEVEL_S_SHIFT;
> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> }
>
> @@ -760,10 +760,10 @@ static ssize_t s_exlevel_vinst_store(struct device *dev,
>
> spin_lock(&drvdata->spinlock);
> /* clear all EXLEVEL_S bits */
> - config->vinst_ctrl &= ~(ETM_EXLEVEL_S_VICTLR_MASK);
> + config->vinst_ctrl &= ~(TRCVICTLR_EXLEVEL_S_MASK);
> /* enable instruction tracing for corresponding exception level */
> val &= drvdata->s_ex_level;
> - config->vinst_ctrl |= (val << 16);
> + config->vinst_ctrl |= (val << TRCVICTLR_EXLEVEL_S_SHIFT);
> spin_unlock(&drvdata->spinlock);
> return size;
> }
> @@ -778,7 +778,7 @@ 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 & ETM_EXLEVEL_NS_VICTLR_MASK) >> 20;
> + val = (config->vinst_ctrl & TRCVICTLR_EXLEVEL_NS_MASK) >> TRCVICTLR_EXLEVEL_NS_SHIFT;
> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> }
>
> @@ -795,10 +795,10 @@ static ssize_t ns_exlevel_vinst_store(struct device *dev,
>
> spin_lock(&drvdata->spinlock);
> /* clear EXLEVEL_NS bits */
> - config->vinst_ctrl &= ~(ETM_EXLEVEL_NS_VICTLR_MASK);
> + config->vinst_ctrl &= ~(TRCVICTLR_EXLEVEL_NS_MASK);
> /* enable instruction tracing for corresponding exception level */
> val &= drvdata->ns_ex_level;
> - config->vinst_ctrl |= (val << 20);
> + config->vinst_ctrl |= (val << TRCVICTLR_EXLEVEL_NS_SHIFT);
> spin_unlock(&drvdata->spinlock);
> return size;
> }
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 2ac4ecb0af61..f1251ddf1984 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -548,24 +548,38 @@
>
> #define TRCACATR_EXLEVEL_SHIFT 8
>
> -/* secure state access levels - TRCACATRn */
> -#define ETM_EXLEVEL_S_APP BIT(8)
> -#define ETM_EXLEVEL_S_OS BIT(9)
> -#define ETM_EXLEVEL_S_HYP BIT(10)
> -#define ETM_EXLEVEL_S_MON BIT(11)
> -/* non-secure state access levels - TRCACATRn */
> -#define ETM_EXLEVEL_NS_APP BIT(12)
> -#define ETM_EXLEVEL_NS_OS BIT(13)
> -#define ETM_EXLEVEL_NS_HYP BIT(14)
> -#define ETM_EXLEVEL_NS_NA BIT(15)
> -
> -/* access level control in TRCVICTLR - same bits as TRCACATRn but shifted */
> -#define ETM_EXLEVEL_LSHIFT_TRCVICTLR 8
> +/*
> + * Exception level mask for Secure and Non-Secure ELs.
> + * ETM defines the bits for EL control (e.g, TRVICTLR, TRCACTRn).
> + * The Secure and Non-Secure ELs are always to gether.
> + * Non-secure EL3 is never implemented.
> + * We use the following generic mask as they appear in different
> + * registers and this can be shifted for the appropriate
> + * fields.
> + */
> +#define ETM_EXLEVEL_S_APP BIT(0) /* Secure EL0 */
> +#define ETM_EXLEVEL_S_OS BIT(1) /* Secure EL1 */
> +#define ETM_EXLEVEL_S_HYP BIT(2) /* Secure EL2 */
> +#define ETM_EXLEVEL_S_MON BIT(3) /* Secure EL3/Montor */

s/Montor/Monitor

> +#define ETM_EXLEVEL_NS_APP BIT(4) /* NonSecure EL0 */
> +#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))

Not used.

> +#define ETM_EXLEVEL_S_MASK (GENMASK(3, 0))
> +#define ETM_EXLEVEL_NS_MASK (GENMASK(6, 4))

This needs to be GENMASK(2, 0) in order TRCVICTLR_EXLEVEL_NS_SHIFT to be 20.
Otherwise the resulting mask is 4 bit off to the left.

> +
> +/* 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 ETM_EXLEVEL_S_VICTLR_MASK GENMASK(19, 16)
> -/* NS MON (EL3) mode never implemented */
> -#define ETM_EXLEVEL_NS_VICTLR_MASK GENMASK(22, 20)
> +#define TRCVICTLR_EXLEVEL_S_MASK (ETM_EXLEVEL_S_MASK << TRCVICTLR_EXLEVEL_S_SHIFT)
> +#define TRCVICTLR_EXLEVEL_NS_MASK (ETM_EXLEVEL_NS_MASK << TRCVICTLR_EXLEVEL_NS_SHIFT)
>
> /* Interpretation of resource numbers change at ETM v4.3 architecture */
> #define ETM4X_ARCH_4V3 0x43
> --
> 2.24.1
>