Re: [PATCH 12/19] coresight: etm4x: Cleanup secure exception level masks

From: Mike Leach <mike.leach@linaro.org>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Coresight ML <coresight@lists.linaro.org>,
	Anshuman.Khandual@arm.com,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Leo Yan <leo.yan@linaro.org>
Subject: Re: [PATCH 12/19] coresight: etm4x: Cleanup secure exception level masks
Date: Fri, 18 Sep 2020 16:35:10 +0100	[thread overview]
Message-ID: <CAJ9a7ViX8EOFvnGExreF7PHHHJPf4q-smNsOjunkEkxkaQHPpQ@mail.gmail.com> (raw)
In-Reply-To: <20200911084119.1080694-13-suzuki.poulose@arm.com>

On Fri, 11 Sep 2020 at 09:41, Suzuki K Poulose <suzuki.poulose@arm.com> 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@arm.com>
> ---
>  drivers/hwtracing/coresight/coresight-etm4x.c | 13 +++----------
>  drivers/hwtracing/coresight/coresight-etm4x.h |  6 ++++--
>  2 files changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
> index 7feb57108bdc..439e9da41006 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -758,7 +758,6 @@ 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);
> @@ -774,6 +773,7 @@ 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);
>
> @@ -935,16 +935,9 @@ 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;
>

What is the << TRCACATR_EXLEVEL_SHIFT doing here?

>         return access_type;
>  }
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index efd903688edd..407ad6647f36 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -522,6 +522,8 @@
>  /* 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)
> @@ -604,7 +606,7 @@
>   * @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;
> @@ -648,7 +650,7 @@ struct etmv4_config {
>         u32                             vmid_mask0;
>         u32                             vmid_mask1;
>         u32                             ext_inp;
> -       u8                              arch;
> +       u8                              s_ex_level;
>  };
>
>  /**
> --
> 2.24.1
>

Perhaps this patch could be combined with the next patch as it
operates on the same set of flags.

Regards

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

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