Detailed description
- This is not a new feature, but still a potentially dangerous change. A sort of continuation of PR2014.
- The existing problem is gdb_main FSM performing VLA for m/M-packets.
- This PR solves it by reusing half of gdb packet buffer for (un)hexify operations.
Tested on BMDA (env CC=clang, -Db_sanitize=address) and on blackpill-f411ce against GD32VF103. Dump and compare-sections seem to match, GDB receives 512 byte (1024 hex-encoded) packets.
g/G-packets still depend on VLA because BMP supports multiple architectures with different amounts of general-purpose registers. {armv7-m 20*4, armv8-m.main 24*4} + fpv4-sp-d16 33*4, armv7-a/r 17*4 + VFPv3 33*4, armv8-a 31*8, rv32i 33*4, rv32e 17*4, rv64i 33*8. IMHO a static regcache of 512 bytes could be enough (with build-time static assert that no arch needs more), but it's not visibly broken now, so not touching.
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
## Detailed description
* This is not a new feature, but still a potentially dangerous change. A sort of continuation of PR2014.
* The existing problem is gdb_main FSM performing VLA for m/M-packets.
* This PR solves it by reusing half of gdb packet buffer for (un)hexify operations.
Tested on BMDA (env CC=clang, -Db_sanitize=address) and on blackpill-f411ce against GD32VF103. Dump and compare-sections seem to match, GDB receives 512 byte (1024 hex-encoded) packets.
g/G-packets still depend on VLA because BMP supports multiple architectures with different amounts of general-purpose registers. `{armv7-m 20*4, armv8-m.main 24*4} + fpv4-sp-d16 33*4, armv7-a/r 17*4 + VFPv3 33*4, armv8-a 31*8, rv32i 33*4, rv32e 17*4, rv64i 33*8.` IMHO a static regcache of 512 bytes could be enough (with build-time static assert that no arch needs more), but it's not visibly broken now, so not touching.
## 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))
* [x] 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
Closes #2042. @perigoso