WIP: Fix: cortexar hardware breakpoints #1894

litui commented 2024年08月15日 00:16:37 +02:00 (Migrated from github.com)

Detailed description

• Hardware breakpoints are now working by bypassing the MMU at the top of the virt_to_phys function when an address is located in RAM. Without this bypass, RAM addresses were being mangled due to inaccurate phys_addr being supplied by the address translation machinery.
• Overriding soft breakpoints to hard breakpoints because GDB automatically selects soft breakpoints when a) a memory map xml is provided, and b) the address is located in RAM. This is not incorrect behaviour, but an override is necessary unless/until soft breakpoints are implemented for cortexar on BMP.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (see Building the firmware)
• It builds as BMDA (see Building the BMDA)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

<!-- Filling this template is mandatory --> ## Detailed description <!-- Explain the **details** for making this change. * Is a new feature implemented? * What existing problem(s) does the pull request solve? * How does the pull request solve these problems? Please provide enough information so that others can review your pull request. Information embedded in the description part of the commits doesn't count. --> * Hardware breakpoints are now working by bypassing the MMU at the top of the `virt_to_phys` function when an address is located in RAM. Without this bypass, RAM addresses were being mangled due to inaccurate `phys_addr` being supplied by the address translation machinery. * Overriding soft breakpoints to hard breakpoints because GDB automatically selects soft breakpoints when a) a memory map xml is provided, and b) the address is located in RAM. This is not incorrect behaviour, but an override is necessary unless/until soft breakpoints are implemented for cortexar on BMP. ## Your checklist for this pull request * [x] I've read the [Code of Conduct](https://github.com/blackmagic-debug/blackmagic/blob/main/CODE_OF_CONDUCT.md) * [x] I've read the [guidelines for contributing](https://github.com/blackmagic-debug/blackmagic/blob/main/CONTRIBUTING.md) to this repository * [x] It builds for hardware native (see [Building the firmware](https://github.com/blackmagic-debug/blackmagic?tab=readme-ov-file#building-black-magic-debug-firmware)) * [x] It builds as BMDA (see [Building the BMDA](https://github.com/blackmagic-debug/blackmagic?tab=readme-ov-file#building-black-magic-debug-app)) * [ ] I've tested it to the best of my ability * [x] My commit messages provide a useful short description of what the commits do ## Closing issues <!-- put "fixes #XXXX" here to auto-close the issue(s) that your PR fixes (if any). -->

litui commented 2024年08月15日 11:09:22 +02:00 (Migrated from github.com)

There, more or less fixed things back to the way I found them with the exception of the RAM address fix. Tested and continuation from a load works, and breakpoints appear to land in the correct places with the check of the address against the RAM. Will look over it all again tomorrow when I'm awake.

There, more or less fixed things back to the way I found them with the exception of the RAM address fix. Tested and continuation from a load works, and breakpoints appear to land in the correct places with the check of the address against the RAM. Will look over it all again tomorrow when I'm awake.

litui commented 2024年08月16日 02:55:40 +02:00 (Migrated from github.com)

For testing purposes (for the Deluge crowd), here are a couple launch.json configs for VSCode and here is the meson cross-file I'm using to build blackmagic

For testing purposes (for the Deluge crowd), [here are a couple launch.json configs for VSCode](https://gist.github.com/litui/b106c49712bbcb06f8211620bbba0d92) and [here is the meson cross-file I'm using to build blackmagic](https://gist.github.com/litui/5b8b1a7e3e8ec2824be89dedd87c306f)

litui commented 2024年09月01日 23:59:03 +02:00 (Migrated from github.com)

This PR will need tweaking after https://github.com/blackmagic-debug/blackmagic/pull/1916 gets merged in.

Edit: done!

This PR will need tweaking after https://github.com/blackmagic-debug/blackmagic/pull/1916 gets merged in. Edit: done!

litui commented 2024年09月02日 02:02:31 +02:00 (Migrated from github.com)

I bumped a request on cortex-debug's repo ( https://github.com/Marus/cortex-debug/issues/978 ) for ability to set the break command used in gdb and then stumbled upon a comment in https://github.com/Marus/cortex-debug/issues/555 which noted that OpenOCD, as a gdb server backend, offers the command gdb_breakpoint_override. Setting this override up as a BMP monitor command might be something to think about.

I bumped a request on cortex-debug's repo ( https://github.com/Marus/cortex-debug/issues/978 ) for ability to set the break command used in gdb and then stumbled upon a comment in https://github.com/Marus/cortex-debug/issues/555 which noted that OpenOCD, as a gdb server backend, offers the command `gdb_breakpoint_override`. Setting this override up as a BMP monitor command might be something to think about.