proc/threads: preserve priority inheritance for SMP

[rmikielis]

Description

Potential priority inheritance race can occur on SMP when contender bumps owner priority while waiting for a lock, but owner releases another lock, before contender was added to lock waiting queue.
This solution just rips proc_threadWaitEx() so thread_common spinlock is not released before contender is added to lock waiting queue. Without some priority inheritance structures (like tree) this is the smallest amount of fixing source code I could come up with, although not very elegant. Feel free to share another ideas.

Motivation and Context

Fixes phoenix-rtos/phoenix-rtos-project#1626

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: ia32-qemu.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[gemini-code-assist]

Code Review

This pull request refactors the lock acquisition loop in _proc_lockSet within proc/threads.c. It replaces the do-while loop and the call to proc_threadWaitEx with an infinite for loop that manually handles thread enqueuing, spinlock clearing/setting, and CPU rescheduling. It also adjusts the interruptible exit checks and spinlock management. There are no review comments, and I have no additional feedback to provide.

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[github-actions]

Unit Test Results

9 821 tests   - 1 039   9 216 ✅  - 974   46m 52s ⏱️ - 6m 11s
  603 suites  -    67     605 💤  -  65 
    1 files   ±    0       0 ❌ ±  0 

Results for commit 141514c. ± Comparison against base commit 11a35ff.

This pull request removes 1039 tests.

flash ‑ armv7a9-zynq7000-zedboard:flash
phoenix-rtos-tests/cpp/hello-cpp ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/cpp/hello-cpp
phoenix-rtos-tests/initfini/main ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/initfini/main
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_in
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_in_big
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_inout
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_inout_big
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_out
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.data_out_big
phoenix-rtos-tests/ioctl/test-ioctl ‑ armv7a9-zynq7000-zedboard:phoenix-rtos-tests/ioctl/test-ioctl.ioctl.in_val
…

♻️ This comment has been updated with latest results.