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Date: Thu, 27 Aug 2015 09:05:33 -0600 From: Mathieu Poirier <mathieu.poirier@...aro.org> To: Chunyan Zhang <zhang.chunyan@...aro.org> Cc: Greg KH <gregkh@...uxfoundation.org>, Mark Brown <broonie@...nel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] Coresight: ETMv4: Prevent TRCRSCTLR0&1 from being accessed On 26 August 2015 at 22:06, Chunyan Zhang <zhang.chunyan@...aro.org> wrote: > 1. TRCRSCTLRn - Resource Selection Control Registers n=0~1 are reserved, > we shouldn't access them. > 2. The max number of 'n' here is defined in TRCIDR4.NUMRSPAIR whoes value > indicates the number of resource selection *pairs*, and 0 indicates > one resource selection pair, 1 indicates two pairs, and so on ... > > So, the total number of resource selection control registers which we can > access is (TRCIDR4.NUMRSPAIR * 2) > > Signed-off-by: Chunyan Zhang <zhang.chunyan@...aro.org> > --- > drivers/hwtracing/coresight/coresight-etm4x.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c > index 1312e99..9425249 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x.c > @@ -136,7 +136,9 @@ static void etm4_enable_hw(void *info) > writel_relaxed(drvdata->cntr_val[i], > drvdata->base + TRCCNTVRn(i)); > } > - for (i = 0; i < drvdata->nr_resource; i++) > + > + /* Resource selector pair 0 is always implemented and reserved */ > + for (i = 2; i < (drvdata->nr_resource + 1) * 2; i++) Instead of repeating "->nr_resource + 1) * 2" every time, please add "->nr_resource += 1" in etm4_init_arch_data() along with a comment that explains why. > writel_relaxed(drvdata->res_ctrl[i], > drvdata->base + TRCRSCTLRn(i)); > > @@ -489,8 +491,9 @@ static ssize_t reset_store(struct device *dev, > drvdata->cntr_val[i] = 0x0; > } > > - drvdata->res_idx = 0x0; > - for (i = 0; i < drvdata->nr_resource; i++) > + /* Resource selector pair 0 is always implemented and reserved */ > + drvdata->res_idx = 0x2; > + for (i = 2; i < (drvdata->nr_resource + 1) * 2; i++) > drvdata->res_ctrl[i] = 0x0; > > for (i = 0; i < drvdata->nr_ss_cmp; i++) { > @@ -1729,7 +1732,7 @@ static ssize_t res_idx_store(struct device *dev, > if (kstrtoul(buf, 16, &val)) > return -EINVAL; > /* Resource selector pair 0 is always implemented and reserved */ > - if ((val == 0) || (val >= drvdata->nr_resource)) > + if (val < 2 || val > (drvdata->nr_resource + 1) * 2) > return -EINVAL; > > /* > @@ -2498,7 +2501,9 @@ static void etm4_init_default_data(struct etmv4_drvdata *drvdata) > drvdata->cntr_val[i] = 0x0; > } > > - for (i = 2; i < drvdata->nr_resource * 2; i++) > + /* Resource selector pair 0 is always implemented and reserved */ > + drvdata->res_idx = 0x2; > + for (i = 2; i < (drvdata->nr_resource + 1) * 2; i++) > drvdata->res_ctrl[i] = 0x0; > > for (i = 0; i < drvdata->nr_ss_cmp; i++) { > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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