| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <9fcc59cf-c76e-8cee-d232-830b31e35060@quicinc.com>
Date: Tue, 28 Mar 2023 17:24:37 +0800
From: Hao Zhang <quic_hazha@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
Mike Leach <mike.leach@...aro.org>
CC: Mathieu Poirier <mathieu.poirier@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Konrad Dybcio <konradybcio@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Andy Gross <agross@...nel.org>,
"Paul Walmsley" <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Jonathan Corbet <corbet@....net>, Leo Yan <leo.yan@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
<coresight@...ts.linaro.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
Tingwei Zhang <quic_tingweiz@...cinc.com>,
Jinlong Mao <quic_jinlmao@...cinc.com>,
"Yuanfang Zhang" <quic_yuanfang@...cinc.com>,
Tao Zhang <quic_taozha@...cinc.com>,
Trilok Soni <quic_tsoni@...cinc.com>,
<linux-arm-msm@...r.kernel.org>,
"Bjorn Andersson" <andersson@...nel.org>,
<linux-doc@...r.kernel.org>
Subject: Re: [PATCH v2 1/3] Coresight: Add coresight dummy driver
Hi Suzuki,
On 3/28/2023 4:35 PM, Suzuki K Poulose wrote:
> On 28/03/2023 08:22, Hao Zhang wrote:
>> Hi Mike,
>>
>> On 3/27/2023 11:58 PM, Mike Leach wrote:
>>> Hi,
>>>
>>> On Fri, 24 Mar 2023 at 06:16, Hao Zhang <quic_hazha@...cinc.com> wrote:
>>>>
>>>> Some Coresight devices that HLOS don't have permission to access
>>>> or configure. Such as Coresight sink EUD, some TPDMs etc. So there
>>>> need driver to register dummy devices as Coresight devices. Provide
>>>> Coresight API for dummy device operations, such as enabling and
>>>> disabling dummy devices. Build the Coresight path for dummy sink or
>>>> dummy source for debugging.
>>>>
>>>> Signed-off-by: Hao Zhang <quic_hazha@...cinc.com>
>>>> ---
>>>> drivers/hwtracing/coresight/Kconfig | 11 ++
>>>> drivers/hwtracing/coresight/Makefile | 1 +
>>>> drivers/hwtracing/coresight/coresight-dummy.c | 176
>>>> ++++++++++++++++++
>>>> 3 files changed, 188 insertions(+)
>>>> create mode 100644 drivers/hwtracing/coresight/coresight-dummy.c
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/Kconfig
>>>> b/drivers/hwtracing/coresight/Kconfig
>>>> index 2b5bbfffbc4f..06f0a7594169 100644
>>>> --- a/drivers/hwtracing/coresight/Kconfig
>>>> +++ b/drivers/hwtracing/coresight/Kconfig
>>>> @@ -236,4 +236,15 @@ config CORESIGHT_TPDA
>>>>
>>>> To compile this driver as a module, choose M here: the
>>>> module will be
>>>> called coresight-tpda.
>>>> +
>>>> +config CORESIGHT_DUMMY
>>>> + tristate "Dummy driver support"
>>>> + help
>>>> + Enables support for dummy driver. Dummy driver can be used
>>>> for
>>>> + CoreSight sources/sinks that are owned and configured by some
>>>> + other subsystem and use Linux drivers to configure rest of
>>>> trace
>>>> + path.
>>>> +
>>>> + To compile this driver as a module, choose M here: the
>>>> module will be
>>>> + called coresight-dummy.
>>>> endif
>>>> diff --git a/drivers/hwtracing/coresight/Makefile
>>>> b/drivers/hwtracing/coresight/Makefile
>>>> index 33bcc3f7b8ae..995d3b2c76df 100644
>>>> --- a/drivers/hwtracing/coresight/Makefile
>>>> +++ b/drivers/hwtracing/coresight/Makefile
>>>> @@ -30,3 +30,4 @@ obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
>>>> coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
>>>> coresight-cti-sysfs.o
>>>> obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
>>>> +obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
>>>> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c
>>>> b/drivers/hwtracing/coresight/coresight-dummy.c
>>>> new file mode 100644
>>>> index 000000000000..2d4eb3e546eb
>>>> --- /dev/null
>>>> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
>>>> @@ -0,0 +1,176 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights
>>>> reserved.
>>>> + */
>>>> +
>>>> +#include <linux/kernel.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/coresight.h>
>>>> +#include <linux/of.h>
>>>> +#include <linux/pm_runtime.h>
>>>> +
>>>> +#include "coresight-priv.h"
>>>> +#include "coresight-trace-id.h"
>>>> +
>>>> +struct dummy_drvdata {
>>>> + struct device *dev;
>>>> + struct coresight_device *csdev;
>>>> + int traceid;
>>>> +};
>>>> +
>>>> +DEFINE_CORESIGHT_DEVLIST(dummy_devs, "dummy");
>>>> +
>>>> +static int dummy_source_enable(struct coresight_device *csdev,
>>>> + struct perf_event *event, u32 mode)
>>>> +{
>>>> + struct dummy_drvdata *drvdata =
>>>> dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> + dev_info(drvdata->dev, "Dummy source enabled\n");
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static void dummy_source_disable(struct coresight_device *csdev,
>>>> + struct perf_event *event)
>>>> +{
>>>> + struct dummy_drvdata *drvdata =
>>>> dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> + dev_info(drvdata->dev, "Dummy source disabled\n");
>>>> +}
>>>> +
>>>> +static int dummy_sink_enable(struct coresight_device *csdev, u32 mode,
>>>> + void *data)
>>>> +{
>>>> + struct dummy_drvdata *drvdata =
>>>> dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> + dev_info(drvdata->dev, "Dummy sink enabled\n");
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int dummy_sink_disable(struct coresight_device *csdev)
>>>> +{
>>>> + struct dummy_drvdata *drvdata =
>>>> dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> + dev_info(drvdata->dev, "Dummy sink disabled\n");
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static const struct coresight_ops_source dummy_source_ops = {
>>>> + .enable = dummy_source_enable,
>>>> + .disable = dummy_source_disable,
>>>> +};
>>>> +
>>>> +static const struct coresight_ops_sink dummy_sink_ops = {
>>>> + .enable = dummy_sink_enable,
>>>> + .disable = dummy_sink_disable,
>>>> +};
>>>> +
>>>> +static const struct coresight_ops dummy_cs_ops = {
>>>> + .source_ops = &dummy_source_ops,
>>>> + .sink_ops = &dummy_sink_ops,
>>>> +};
>>>> +
>>>> +static int dummy_probe(struct platform_device *pdev)
>>>> +{
>>>> + int ret, trace_id;
>>>> + struct device *dev = &pdev->dev;
>>>> + struct coresight_platform_data *pdata;
>>>> + struct dummy_drvdata *drvdata;
>>>> + struct coresight_desc desc = { 0 };
>>>> +
>>>> + desc.name = coresight_alloc_device_name(&dummy_devs, dev);
>>>> + if (!desc.name)
>>>> + return -ENOMEM;
>>>> +
>>>> + pdata = coresight_get_platform_data(dev);
>>>> + if (IS_ERR(pdata))
>>>> + return PTR_ERR(pdata);
>>>> + pdev->dev.platform_data = pdata;
>>>> +
>>>> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
>>>> + if (!drvdata)
>>>> + return -ENOMEM;
>>>> +
>>>> + drvdata->dev = &pdev->dev;
>>>> + platform_set_drvdata(pdev, drvdata);
>>>> +
>>>> + if (of_property_read_bool(pdev->dev.of_node,
>>>> "qcom,dummy-source")) {
>>>> + desc.type = CORESIGHT_DEV_TYPE_SOURCE;
>>>> + desc.subtype.source_subtype =
>>>> + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
>>>> + } else if (of_property_read_bool(pdev->dev.of_node,
>>>> + "qcom,dummy-sink")) {
>>>> + desc.type = CORESIGHT_DEV_TYPE_SINK;
>>>> + desc.subtype.sink_subtype =
>>>> CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
>>>
>>> This will break the automatic sink selection on a system where perf is
>>> looking for a default sink and the dummy sink is closest / first
>>> discovered.
>>>
>>> i.e. when perf record -e cs_etm// <options>
>>> is used to trace a program in linux, a dummy sink appearing in the
>>> coresight tree with this designation may be selected.
>>>
>>> This needs to be corrected, probably with a unique sub-type that
>>> appears before the CORESIGHT_DEV_SUBTYPE_SINK_BUFFER value in the enum
>>> as the selection is based on >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER.
>>>
>
> Good point Mike.
>
>>> By implication adding a new value - will possibly affect other code
>>> using the enum values so will need to be checked
>>>
>>> Regards
>>>
>>> Mike
>>>
>>
>> Thanks for your comments, I will add a new sub-type for dummy sink and
>> check the impact of it.
>
> Please keep this as the lowest priority, something like:
>
> enum coresight_dev_subtype_sink {
> + CORESIGHT_DEV_SUBTYPE_SINK_DUMMY,
> CORESIGHT_DEV_SUBTYPE_SINK_PORT,
> CORESIGHT_DEV_SUBTYPE_SINK_BUFFER,
> CORESIGHT_DEV_SUBTYPE_SINK_SYSMEM,
> CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM,
> };
>
> This should be fine without any impact on the existing code, as we
> expect the driver modules to be updated with the new core module.
>
> Suzuki
>
Sure, I will take your advice in the next version of patch.
Thanks,
Hao
>
>>
>> Thanks,
>> Hao
>>
>>>
>>>> + } else {
>>>> + dev_info(dev, "Device type not set\n");
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + desc.ops = &dummy_cs_ops;
>>>> + desc.pdata = pdev->dev.platform_data;
>>>> + desc.dev = &pdev->dev;
>>>> + drvdata->csdev = coresight_register(&desc);
>>>> + if (IS_ERR(drvdata->csdev))
>>>> + return PTR_ERR(drvdata->csdev);
>>>> +
>>>> + trace_id = coresight_trace_id_get_system_id();
>>>> + if (trace_id < 0) {
>>>> + ret = trace_id;
>>>> + goto cs_unregister;
>>>> + }
>>>> + drvdata->traceid = (u8)trace_id;
>>>> +
>>>> + pm_runtime_enable(dev);
>>>> + dev_info(dev, "Dummy device initialized\n");
>>>> +
>>>> + return 0;
>>>> +
>>>> +cs_unregister:
>>>> + coresight_unregister(drvdata->csdev);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static int dummy_remove(struct platform_device *pdev)
>>>> +{
>>>> + struct dummy_drvdata *drvdata = platform_get_drvdata(pdev);
>>>> + struct device *dev = &pdev->dev;
>>>> +
>>>> + coresight_trace_id_put_system_id(drvdata->traceid);
>>>> + pm_runtime_disable(dev);
>>>> + coresight_unregister(drvdata->csdev);
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static const struct of_device_id dummy_match[] = {
>>>> + {.compatible = "qcom,coresight-dummy"},
>>>> + {},
>>>> +};
>>>> +
>>>> +static struct platform_driver dummy_driver = {
>>>> + .probe = dummy_probe,
>>>> + .remove = dummy_remove,
>>>> + .driver = {
>>>> + .name = "coresight-dummy",
>>>> + .of_match_table = dummy_match,
>>>> + },
>>>> +};
>>>> +
>>>> +static int __init dummy_init(void)
>>>> +{
>>>> + return platform_driver_register(&dummy_driver);
>>>> +}
>>>> +module_init(dummy_init);
>>>> +
>>>> +static void __exit dummy_exit(void)
>>>> +{
>>>> + platform_driver_unregister(&dummy_driver);
>>>> +}
>>>> +module_exit(dummy_exit);
>>>> +
>>>> +MODULE_LICENSE("GPL");
>>>> +MODULE_DESCRIPTION("CoreSight dummy source driver");
>>>> --
>>>> 2.17.1
>>>>
>>>
>>>
>
Powered by blists - more mailing lists