Ivan Grokhotkov 0adf0f85dd gdbstub: fix thread list generation
This commit fixes an issue with gdbstub, where it would list threads
with TIDs 1 to N in qfThreadInfo/qsThreadInfo responses, and then
would tell GDB that the current TID is 0 in the qC response. This
caused an assertion failure in GDB, because it couldn't find the
thread structure corresponding to TID 0:

src/gdb/gdb/thread.c:93: internal-error: thread_info* inferior_thread(): Assertion `tp' failed.

The issue was caused by the logic of qfThreadInfo/qsThreadInfo.
If the "paniced" task index was 1, the code would report it in the
response to qfThreadInfo, and then mistakenly skip task with index 0
in qsThreadInfo, due to the use of pre-increment instead of a
post-increment.

With that issue fixed, GDB assertion doesn't happen anymore. However
the code contained a deeper problem, which manifested itself in the
fact that GDB would incorrectly show task index 0 as the current task,
after the above fix.

Previous version of the code assumed that when GDB requests the thread
list, it uses the first thread returned by the target as the "default"
thread, and subsequently shows the user that the program is stopped
in that thread. This assumption was incorrect. In fact, after
connecting to a remote target, GDB obtains information about the
"default" or "current" thread from two sources:
1. the 'thread' special register indicated in the status response
   ($T00thread;00000001#ee)
2. if the target has only sent the plain stop response ($T00#ee), GDB
   would ask for the current thread using a qC packet.
With that in mind, it is not necessary to report the paniced task as
the first task in qfThreadInfo response. We can simply returns the
tasks in their natural order, and then indicate the current task in
the qS packet response.

However even that change does not fully resolve the issues with task
list. The previous version of this code also incorrectly interpreted
the meaning of GDB TIDs -1 and 0. When GDB sends an "Hg0" command
early in the connection process, it doesn't expect the server to set
task 0 as the current task, as the code assumed. Rather, it tells the
server to "set any (arbitrary) task as the current one", and the most
logical thing to do for the server that is already in "stopped" state
is to keep the current task selection.

Since TID 0 has a special meaning in GDB remote protocol, gdbstub code
is now modified to map task indices (which start from 0) to GDB TIDs.
GDB TIDs are arbitrary, and for simplicity we keep the same order and
start counting them from 1.

The summary of all the above changes is:

1. Use "task index + 1" as the TID reported to GDB
2. Report the tasks in natural order; don't complicate the code to
   make the paniced task first in the list.
3. Centralize modification of 'current_task_index' and 'regfile'
   in the new 'set_active_task' function, to improve encapsulation.
2021-06-18 16:02:10 +02:00
2021-06-16 14:49:39 +08:00
2020-05-05 11:08:33 +02:00
2019-08-27 13:45:50 +08:00
2016-08-17 23:08:22 +08:00

Espressif IoT Development Framework

ESP-IDF is the development framework for Espressif SoCs (released after 20161) provided for Windows, Linux and macOS.

Developing With ESP-IDF

Setting Up ESP-IDF

See https://idf.espressif.com/ for links to detailed instructions on how to set up the ESP-IDF depending on chip you use.

Note: Each SoC series and each ESP-IDF release has its own documentation. Please see Section Versions on how to find documentation and how to checkout specific release of ESP-IDF.

Non-GitHub forks

ESP-IDF uses relative locations as its submodules URLs (.gitmodules). So they link to GitHub. If ESP-IDF is forked to a Git repository which is not on GitHub, you will need to run the script tools/set-submodules-to-github.sh after git clone. The script sets absolute URLs for all submodules, allowing git submodule update --init --recursive to complete. If cloning ESP-IDF from GitHub, this step is not needed.

Finding a Project

As well as the esp-idf-template project mentioned in Getting Started, ESP-IDF comes with some example projects in the examples directory.

Once you've found the project you want to work with, change to its directory and you can configure and build it.

To start your own project based on an example, copy the example project directory outside of the ESP-IDF directory.

Quick Reference

See the Getting Started guide links above for a detailed setup guide. This is a quick reference for common commands when working with ESP-IDF projects:

Setup Build Environment

(See the Getting Started guide listed above for a full list of required steps with more details.)

  • Install host build dependencies mentioned in the Getting Started guide.
  • Run the install script to set up the build environment. The options include install.bat or install.ps1 for Windows, and install.sh or install.fish for Unix shells.
  • Run the export script on Windows (export.bat) or source it on Unix (source export.sh) in every shell environment before using ESP-IDF.

Configuring the Project

  • idf.py set-target <chip_name> sets the target of the project to <chip_name>. Run idf.py set-target without any arguments to see a list of supported targets.
  • idf.py menuconfig opens a text-based configuration menu where you can configure the project.

Compiling the Project

idf.py build

... will compile app, bootloader and generate a partition table based on the config.

Flashing the Project

When the build finishes, it will print a command line to use esptool.py to flash the chip. However you can also do this automatically by running:

idf.py -p PORT flash

Replace PORT with the name of your serial port (like COM3 on Windows, /dev/ttyUSB0 on Linux, or /dev/cu.usbserial-X on MacOS. If the -p option is left out, idf.py flash will try to flash the first available serial port.

This will flash the entire project (app, bootloader and partition table) to a new chip. The settings for serial port flashing can be configured with idf.py menuconfig.

You don't need to run idf.py build before running idf.py flash, idf.py flash will automatically rebuild anything which needs it.

Viewing Serial Output

The idf.py monitor target uses the idf_monitor tool to display serial output from Espressif SoCs. idf_monitor also has a range of features to decode crash output and interact with the device. Check the documentation page for details.

Exit the monitor by typing Ctrl-].

To build, flash and monitor output in one pass, you can run:

idf.py flash monitor

Compiling & Flashing Only the App

After the initial flash, you may just want to build and flash just your app, not the bootloader and partition table:

  • idf.py app - build just the app.
  • idf.py app-flash - flash just the app.

idf.py app-flash will automatically rebuild the app if any source files have changed.

(In normal development there's no downside to reflashing the bootloader and partition table each time, if they haven't changed.)

Erasing Flash

The idf.py flash target does not erase the entire flash contents. However it is sometimes useful to set the device back to a totally erased state, particularly when making partition table changes or OTA app updates. To erase the entire flash, run idf.py erase_flash.

This can be combined with other targets, ie idf.py -p PORT erase_flash flash will erase everything and then re-flash the new app, bootloader and partition table.

Resources


1: ESP8266 and ESP8285 are not supported in ESP-IDF. See RTOS SDK instead.

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