From: Mukesh Ojha <quic_mojha@quicinc.com>
To: <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>,
"Mukesh Ojha" <quic_mojha@quicinc.com>
Subject: [PATCH v3 03/18] docs: qcom: Add qualcomm minidump guide
Date: Wed, 3 May 2023 22:32:17 +0530 [thread overview]
Message-ID: <1683133352-10046-4-git-send-email-quic_mojha@quicinc.com> (raw)
In-Reply-To: <1683133352-10046-1-git-send-email-quic_mojha@quicinc.com>
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
+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
+ SS-ToC: Subsystem table of content
+ 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
+allocates a small section of it to minidump table i.e also called
+global table of content (G-ToC). Each subsystem (APSS, ADSP, ...) has
+their own table of segments to be included in the minidump, all
+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
+could be anywhere scattered in the DDR.
+
+Minidump kernel driver concept
+------------------------------
+
+Qualcomm minidump kernel driver adds the capability to add linux region
+to be dumped as part of ram dump collection. At the moment, shared memory
+driver creates plaform device for minidump driver and give a means to
+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
+address for the client whose addresses keeps on changing e.g Current stack
+address of task keep on changing on context switch for each core. So these
+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
+header as first region that gets updated each time a new region gets
+registered.
+
+The solution supports extracting the ramdump/minidump produced either
+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
+firmware whether it supports minidump or not. So, if the minidump
+smem id is present in shared memory, it indicates that minidump
+is supported from boot firmware and it is possible to dump 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
+structure object which consist of the region name, region's
+virtual and physical address and its size.
+
+Below is one sample client driver snippet which try to allocate
+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
+full dump) by writing appropriate value to Qualcomm's top control and
+status register(tcsr) in driver/firmware/qcom_scm.c .
+
+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"
+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
+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
+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
+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
+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
+starts with md_*.
+
+Replacing the dexter.exe with some open source tool can be added as future
+scope of this document.
--
2.7.4
next prev parent reply other threads:[~2023-05-03 17:03 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 ` Mukesh Ojha [this message]
2023-05-08 10:01 ` [PATCH v3 03/18] docs: qcom: Add qualcomm minidump guide Bagas Sanjaya
2023-05-25 16:00 ` Mukesh Ojha
2023-05-13 18:46 ` Randy Dunlap
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1683133352-10046-4-git-send-email-quic_mojha@quicinc.com \
--to=quic_mojha@quicinc.com \
--cc=agross@kernel.org \
--cc=andersson@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=gpiccoli@igalia.com \
--cc=keescook@chromium.org \
--cc=konrad.dybcio@linaro.org \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=linus.walleij@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-remoteproc@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=srinivas.kandagatla@linaro.org \
--cc=tony.luck@intel.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).