From: Randy Dunlap <rdunlap@infradead.org>
To: Mukesh Ojha <quic_mojha@quicinc.com>,
agross@kernel.org, andersson@kernel.org,
konrad.dybcio@linaro.org, corbet@lwn.net, keescook@chromium.org,
tony.luck@intel.com, gpiccoli@igalia.com,
catalin.marinas@arm.com, will@kernel.org,
krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org,
linus.walleij@linaro.org, linux-gpio@vger.kernel.org,
srinivas.kandagatla@linaro.org
Cc: linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH v3 03/18] docs: qcom: Add qualcomm minidump guide
Date: Sat, 13 May 2023 11:46:39 -0700 [thread overview]
Message-ID: <2ce73561-ce8a-b288-a5ab-254e5d2070f1@infradead.org> (raw)
In-Reply-To: <1683133352-10046-4-git-send-email-quic_mojha@quicinc.com>
On 5/3/23 10:02, Mukesh Ojha wrote:
> Add the qualcomm minidump guide for the users which
> tries to cover the dependency and the way to test
> and collect minidump on Qualcomm supported platforms.
>
> Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
> ---
> Documentation/admin-guide/qcom_minidump.rst | 246 ++++++++++++++++++++++++++++
> 1 file changed, 246 insertions(+)
> create mode 100644 Documentation/admin-guide/qcom_minidump.rst
>
> diff --git a/Documentation/admin-guide/qcom_minidump.rst b/Documentation/admin-guide/qcom_minidump.rst
> new file mode 100644
> index 0000000..062c797
> --- /dev/null
> +++ b/Documentation/admin-guide/qcom_minidump.rst
> @@ -0,0 +1,246 @@
> +Qualcomm Minidump Feature
> +=========================
> +
> +Introduction
> +------------
> +
> +Minidump is a best effort mechanism to collect useful and predefined
> +data for first level of debugging on end user devices running on
> +Qualcomm SoCs. It is built on the premise that System on Chip (SoC)
> +or subsystem part of SoC crashes, due to a range of hardware and
> +software bugs. Hence, the ability to collect accurate data is only
> +a best-effort. The data collected could be invalid or corrupted, data
> +collection itself could fail, and so on.
> +
> +Qualcomm devices in engineering mode provides a mechanism for generating
> +full system ramdumps for post mortem debugging. But in some cases it's
RAM dumps for {post-mortem or postmortem} debugging.
> +however not feasible to capture the entire content of RAM. The minidump
> +mechanism provides the means for selecting region should be included in
> +the ramdump.
> +
> +::
> +
> + +-----------------------------------------------+
> + | DDR +-------------+ |
> + | | SS0-ToC| |
> + | +----------------+ +----------------+ | |
> + | |Shared memory | | SS1-ToC| | |
> + | |(SMEM) | | | | |
> + | | | +-->|--------+ | | |
> + | |G-ToC | | | SS-ToC \ | | |
> + | |+-------------+ | | | +-----------+ | | |
> + | ||-------------| | | | |-----------| | | |
> + | || SS0-ToC | | | +-|<|SS1 region1| | | |
> + | ||-------------| | | | | |-----------| | | |
> + | || SS1-ToC |-|>+ | | |SS1 region2| | | |
> + | ||-------------| | | | |-----------| | | |
> + | || SS2-ToC | | | | | ... | | | |
> + | ||-------------| | | | |-----------| | | |
> + | || ... | | |-|<|SS1 regionN| | | |
> + | ||-------------| | | | |-----------| | | |
> + | || SSn-ToC | | | | +-----------+ | | |
> + | |+-------------+ | | | | | |
> + | | | | |----------------| | |
> + | | | +>| regionN | | |
> + | | | | |----------------| | |
> + | +----------------+ | | | | |
> + | | |----------------| | |
> + | +>| region1 | | |
> + | |----------------| | |
> + | | | | |
> + | |----------------|-+ |
> + | | region5 | |
> + | |----------------| |
> + | | | |
> + | Region information +----------------+ |
> + | +---------------+ |
> + | |region name | |
> + | |---------------| |
> + | |region address | |
> + | |---------------| |
> + | |region size | |
> + | +---------------+ |
> + +-----------------------------------------------+
> + G-ToC: Global table of content
contents
?
> + SS-ToC: Subsystem table of content
contents
?
> + SS0-SSn: Subsystem numbered from 0 to n
> +
> +The core of minidump feature is part of Qualcomm's boot firmware code.
> +It initializes shared memory(SMEM), which is a part of DDR and
memory (SMEM),
> +allocates a small section of it to minidump table i.e also called
table, i.e.
> +global table of content (G-ToC). Each subsystem (APSS, ADSP, ...) has
contents
> +their own table of segments to be included in the minidump, all
its own table
> +references from a descriptor in SMEM (G-ToC). Each segment/region has
> +some details like name, physical address and it's size etc. and it
its
> +could be anywhere scattered in the DDR.
> +
> +Minidump kernel driver concept
> +------------------------------
> +
> +Qualcomm minidump kernel driver adds the capability to add linux region
Linux
> +to be dumped as part of ram dump collection. At the moment, shared memory
RAM
> +driver creates plaform device for minidump driver and give a means to
platform
> +APSS minidump to initialize itself on probe.
> +
> +This driver provides ``qcom_apss_minidump_region_register`` and
> +``qcom_apss_minidump_region_unregister`` API's to register and unregister
> +apss minidump region. It also gives a mechanism to update physical/virtual
APSS
> +address for the client whose addresses keeps on changing e.g Current stack
changing, e.g., current stack
> +address of task keep on changing on context switch for each core. So these
keeps
> +clients can update their addresses with ``qcom_apss_minidump_update_region``
> +API.
> +
> +The driver also supports registration for the clients who came before
> +minidump driver was initialized. It maintains pending list of clients
> +who came before minidump and once minidump is initialized it registers
> +them in one go.
> +
> +To simplify post mortem debugging, driver creates and maintain an ELF
choose one: postmortem or post-mortem
> +header as first region that gets updated each time a new region gets
> +registered.
> +
> +The solution supports extracting the ramdump/minidump produced either
RAM dump/minidump
> +over USB or stored to an attached storage device.
> +
> +Dependency of minidump kernel driver
> +------------------------------------
> +
> +It is to note that whole of minidump thing depends on Qualcomm boot
s/thing //
> +firmware whether it supports minidump or not. So, if the minidump
> +smem id is present in shared memory, it indicates that minidump
SMEM ID
> +is supported from boot firmware and it is possible to dump linux
Linux
> +(APSS) region as part of minidump collection.
> +
> +How a kernel client driver can register region with minidump
> +------------------------------------------------------------
> +
> +Client driver can use ``qcom_apss_minidump_region_register`` API's to
> +register and ``qcom_apss_minidump_region_unregister`` to unregister
> +their region from minidump driver.
> +
> +Client need to fill their region by filling qcom_apss_minidump_region
needs
> +structure object which consist of the region name, region's
consists
> +virtual and physical address and its size.
> +
> +Below is one sample client driver snippet which try to allocate
tries
> +a region from kernel heap of certain size and it writes a certain
> +known pattern (that can help in verification after collection
> +that we got the exact pattern, what we wrote) and registers it with
> +minidump.
> +
> + .. code-block:: c
> +
> + #include <soc/qcom/qcom_minidump.h>
> + [...]
> +
> +
> + [... inside a function ...]
> + struct qcom_apss_minidump_region region;
> +
> + [...]
> +
> + client_mem_region = kzalloc(region_size, GFP_KERNEL);
> + if (!client_mem_region)
> + return -ENOMEM;
> +
> + [... Just write a pattern ...]
> + memset(client_mem_region, 0xAB, region_size);
> +
> + [... Fill up the region object ...]
> + strlcpy(region.name, "REGION_A", sizeof(region.name));
> + region.virt_addr = client_mem_region;
> + region.phys_addr = virt_to_phys(client_mem_region);
> + region.size = region_size;
> +
> + ret = qcom_apss_minidump_region_register(®ion);
> + if (ret < 0) {
> + pr_err("failed to add region in minidump: err: %d\n", ret);
> + return ret;
> + }
> +
> + [...]
> +
> +
> +Test
> +----
> +
> +Existing Qualcomm devices already supports entire ddr dump (also called
DDR
> +full dump) by writing appropriate value to Qualcomm's top control and
> +status register(tcsr) in driver/firmware/qcom_scm.c .
register (tcsr)
> +
> +SCM device Tree bindings required to support download mode
> +For example (sm8450) ::
> +
> + / {
> +
> + [...]
> +
> + firmware {
> + scm: scm {
> + compatible = "qcom,scm-sm8450", "qcom,scm";
> + [... tcsr register ... ]
> + qcom,dload-mode = <&tcsr 0x13000>;
> +
> + [...]
> + };
> + };
> +
> + [...]
> +
> + soc: soc@0 {
> +
> + [...]
> +
> + tcsr: syscon@1fc0000 {
> + compatible = "qcom,sm8450-tcsr", "syscon";
> + reg = <0x0 0x1fc0000 0x0 0x30000>;
> + };
> +
> + [...]
> + };
> + [...]
> +
> + };
> +
> +User of minidump can pass qcom_scm.download_mode="mini" to kernel
> +commandline to set the current download mode to minidump.
> +Similarly, "full" is passed to set the download mode to full dump
> +where entire ddr dump will be collected while setting it "full,mini"
DDR
> +will collect minidump along with fulldump.
> +
> +Writing to sysfs node can also be used to set the mode to minidump.
> +
> +::
> + echo "mini" > /sys/module/qcom_scm/parameter/download_mode
> +
> +Once the download mode is set, any kind of crash will make the device collect
> +respective dump as per set download mode.
> +
> +Dump collection
> +---------------
> +
> +The solution supports extracting the minidump produced either over USB or
> +stored to an attached storage device.
> +
> +By default, dumps are downloaded via USB to the attached x86_64 machine
> +running PCAT (Qualcomm tool) software. Upon download, we will see
> +a set of binary blobs starts with name md_* in PCAT configured directory
starting
> +in x86_64 machine, so for above example from the client it will be
> +md_REGION_A.BIN. This binary blob depends on region content to determine
> +whether it needs external parser support to get the content of the region,
> +so for simple plain ASCII text we don't need any parsing and the content
> +can be seen just opening the binary file.
> +
> +To collect the dump to attached storage type, one need to write appropriate
needs
> +value to IMEM register, in that case dumps are collected in rawdump
> +partition on the target device itself.
> +
> +One need to read the entire rawdump partition and pull out content to
needs
> +save it onto the attached x86_64 machine over USB. Later, this rawdump
> +can be pass it to another tool dexter.exe(Qualcomm tool) which converts
passed dexter.exe (Qualcomm tool)
> +this into the similar binary blobs which we have got it when download type
> +was set to USB i.e a set of registered region as blobs and their name
USB, i.e. regions
> +starts with md_*.
> +
> +Replacing the dexter.exe with some open source tool can be added as future
> +scope of this document.
--
~Randy
next prev parent reply other threads:[~2023-05-13 18:47 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-03 17:02 [PATCH v3 00/18] Add basic Minidump kernel driver support Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 01/18] remoteproc: qcom: Expand MD_* as MINIDUMP_* Mukesh Ojha
2023-05-04 12:35 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 02/18] remoteproc: qcom: Move minidump specific data to qcom_minidump.h Mukesh Ojha
2023-05-04 11:38 ` Krzysztof Kozlowski
2023-05-04 11:58 ` Mukesh Ojha
2023-05-04 12:03 ` Krzysztof Kozlowski
2023-05-04 12:26 ` Mukesh Ojha
2023-05-04 12:36 ` Krzysztof Kozlowski
2023-05-04 12:57 ` Mukesh Ojha
2023-05-04 15:16 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 03/18] docs: qcom: Add qualcomm minidump guide Mukesh Ojha
2023-05-08 10:01 ` Bagas Sanjaya
2023-05-25 16:00 ` Mukesh Ojha
2023-05-13 18:46 ` Randy Dunlap [this message]
2023-05-25 15:59 ` Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 04/18] soc: qcom: Add Qualcomm minidump kernel driver Mukesh Ojha
2023-05-04 11:36 ` Krzysztof Kozlowski
2023-05-04 12:38 ` Mukesh Ojha
2023-05-04 15:21 ` Krzysztof Kozlowski
2023-05-04 16:34 ` Krzysztof Kozlowski
2023-05-08 7:10 ` Mukesh Ojha
2023-05-09 7:11 ` Krzysztof Kozlowski
2023-05-28 11:29 ` Mukesh Ojha
2023-05-14 4:16 ` Trilok Soni
2023-05-05 5:34 ` Mukesh Ojha
2023-06-02 10:43 ` Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 05/18] soc: qcom: minidump: Add pending region registration support Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 06/18] soc: qcom: minidump: Add update region support Mukesh Ojha
2023-05-04 11:40 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 07/18] arm64: defconfig: Enable Qualcomm minidump driver Mukesh Ojha
2023-05-04 11:23 ` Krzysztof Kozlowski
2023-05-04 11:45 ` Mukesh Ojha
2023-05-04 12:32 ` Krzysztof Kozlowski
2023-05-04 14:43 ` Mukesh Ojha
2023-05-04 15:24 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 08/18] remoterproc: qcom: refactor to leverage exported minidump symbol Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 09/18] soc: qcom: Add qcom's pstore minidump driver support Mukesh Ojha
2023-05-04 15:35 ` Krzysztof Kozlowski
2023-05-09 16:06 ` Luca Stefani
2023-05-16 20:48 ` Kees Cook
2023-05-03 17:02 ` [PATCH v3 10/18] dt-bindings: reserved-memory: Add qcom,ramoops-minidump binding Mukesh Ojha
2023-05-04 11:22 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 11/18] arm64: dts: qcom: sm8450: Add Qualcomm ramoops minidump node Mukesh Ojha
2023-05-04 7:14 ` Konrad Dybcio
2023-05-04 11:26 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 12/18] soc: qcom: Register pstore frontend region with minidump Mukesh Ojha
2023-05-09 15:45 ` Luca Stefani
2023-05-16 20:50 ` Kees Cook
2023-05-03 17:02 ` [PATCH v3 13/18] arm64: defconfig: Enable Qualcomm pstore minidump client driver Mukesh Ojha
2023-05-04 11:23 ` Krzysztof Kozlowski
2023-05-03 17:02 ` [PATCH v3 14/18] firmware: qcom_scm: provide a read-modify-write function Mukesh Ojha
2023-05-18 18:48 ` Trilok Soni
2023-05-03 17:02 ` [PATCH v3 15/18] pinctrl: qcom: Use qcom_scm_io_update_field() Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 16/18] firmware: scm: Modify only the download bits in TCSR register Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 17/18] firmware: qcom_scm: Refactor code to support multiple download mode Mukesh Ojha
2023-05-03 17:02 ` [PATCH v3 18/18] firmware: qcom_scm: Add multiple download mode support Mukesh Ojha
2023-05-04 11:26 ` [PATCH v3 00/18] Add basic Minidump kernel driver support Krzysztof Kozlowski
2023-07-15 22:13 ` (subset) " Bjorn Andersson
2023-07-17 1:15 ` Mathieu Poirier
2023-07-17 8:02 ` Krzysztof Kozlowski
2023-07-17 16:21 ` Bjorn Andersson
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