linux-kernel - Re: [PATCH v3 17/26] coresight: etm4x: Cleanup secure exception level masks

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Message-ID: <20201105215526.GC3047244@xps15>
Date:   Thu, 5 Nov 2020 14:55:26 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, mike.leach@...aro.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 17/26] coresight: etm4x: Cleanup secure exception
 level masks

On Wed, Oct 28, 2020 at 10:09:36PM +0000, Suzuki K Poulose wrote:
> We rely on the ETM architecture version to decide whether
> Secure EL2 is available on the CPU for excluding the level
> for address comparators and viewinst main control register.
> We must instead use the TRCDIDR3.EXLEVEL_S field to detect
> the supported levels.
> 
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>  drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++----------
>  drivers/hwtracing/coresight/coresight-etm4x.h      |  6 ++++--
>  2 files changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index a12d58a04c5d..6e3f9cb7de3f 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -733,7 +733,6 @@ static void etm4_init_arch_data(void *info)
>  	 * TRCARCHMAJ, bits[11:8] architecture major versin number
>  	 */
>  	drvdata->arch = BMVAL(etmidr1, 4, 11);
> -	drvdata->config.arch = drvdata->arch;
>  
>  	/* maximum size of resources */
>  	etmidr2 = etm4x_relaxed_read32(csa, TRCIDR2);
> @@ -749,6 +748,7 @@ static void etm4_init_arch_data(void *info)
>  	drvdata->ccitmin = BMVAL(etmidr3, 0, 11);
>  	/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */
>  	drvdata->s_ex_level = BMVAL(etmidr3, 16, 19);
> +	drvdata->config.s_ex_level = drvdata->s_ex_level;
>  	/* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */
>  	drvdata->ns_ex_level = BMVAL(etmidr3, 20, 23);
>  
> @@ -920,16 +920,9 @@ static u64 etm4_get_ns_access_type(struct etmv4_config *config)
>  static u64 etm4_get_access_type(struct etmv4_config *config)
>  {
>  	u64 access_type = etm4_get_ns_access_type(config);
> -	u64 s_hyp = (config->arch & 0x0f) >= 0x4 ? ETM_EXLEVEL_S_HYP : 0;
>  
> -	/*
> -	 * EXLEVEL_S, bits[11:8], don't trace anything happening
> -	 * in secure state.
> -	 */
> -	access_type |= (ETM_EXLEVEL_S_APP	|
> -			ETM_EXLEVEL_S_OS	|
> -			s_hyp			|
> -			ETM_EXLEVEL_S_MON);
> +	/* All supported secure ELs are excluded */
> +	access_type |= (u64)config->s_ex_level << TRCACATR_EXLEVEL_SHIFT;
>  
>  	return access_type;
>  }
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index e7f6b7b16fb7..2ac4ecb0af61 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -546,6 +546,8 @@
>  /* PowerDown Control Register bits */
>  #define TRCPDCR_PU			BIT(3)
>  
> +#define TRCACATR_EXLEVEL_SHIFT		8
> +
>  /* secure state access levels - TRCACATRn */
>  #define ETM_EXLEVEL_S_APP		BIT(8)
>  #define ETM_EXLEVEL_S_OS		BIT(9)
> @@ -615,7 +617,7 @@
>   * @vmid_mask0:	VM ID comparator mask for comparator 0-3.
>   * @vmid_mask1:	VM ID comparator mask for comparator 4-7.
>   * @ext_inp:	External input selection.
> - * @arch:	ETM architecture version (for arch dependent config).
> + * @s_ex_level: Secure ELs where tracing is supported.
>   */
>  struct etmv4_config {
>  	u32				mode;
> @@ -659,7 +661,7 @@ struct etmv4_config {
>  	u32				vmid_mask0;
>  	u32				vmid_mask1;
>  	u32				ext_inp;
> -	u8				arch;
> +	u8				s_ex_level;

Instead of making s_ex_level redundant I suggest to pass a struct etmv4_drvdata
to etm4_get_access_type().

More comments to come tomorrow.

Thanks,
Mathieu

>  };
>  
>  /**
> -- 
> 2.24.1
>