sched: Fix MISRA-C violations

[Fix-Point]

Summary

This pull request consists of a series of commits primarily focused on improving code quality, enhancing type safety, addressing compilation warnings, and ensuring compliance with MISRA-C coding standards across various subsystems of the NuttX operating system.

Impact

• Users (Application Developers): The changes are largely internal and should not affect the functional behavior or the public POSIX API for applications (e.g., timer_create, sem_wait, clock_gettime). The primary user-facing impact is increased code reliability and stability due to stricter type checking and error handling.
• Code Quality and Maintenance: By addressing MISRA-C violations and eliminating compiler warnings, the codebase becomes more portable, predictable, and easier to maintain. The refactoring in the timer subsystem (removing early returns, simplifying logic) improves readability and reduces the risk of latent bugs.
• Compatibility: The modifications maintain backward source compatibility. However, developers who directly relied on the internal nxclock_settime() symbol will need to adapt, as it has been removed.
• Documentation: No direct impact on external documentation. The inline comments within the code are updated to reflect some of the logic changes.
• Security: While not a direct security patch, the overall hardening (e.g., stricter input validation) contributes to the system's robustness against potential misuse.

Test

Tested on rv-virt:smp, ostest passed.

[acassis]

@Fix-Point seems like we defined a symbol that is defined in nimble:

/github/workspace/sources/apps/wireless/bluetooth/nimble/mynewt-nimble/nimble/host/src/ble_gatts_lcl.c:95: error: "STRINGIFY" redefined [-Werror]

[acassis]

@simbit18 any idea why we are getting this error only now? This symbol was defined many years ago: #14187

Maybe the issue came from some recent modification to nimble?

[simbit18]

Hi @acassis I think it's related to some recent changes.

This is also present in the msvc job.( is linked to this change ‎include/nuttx/macro.h )

====================================================================================
Configuration/Tool: sim\windows
2026-01-21 13:29:33
------------------------------------------------------------------------------------
  Cleaning...
  Configuring...
  Select HOST_WINDOWS=y
  Select WINDOWS_NATIVE=y
   TOOLS_DIR path is "D:/a/nuttx/nuttx/sources/nuttx"
   HOST = WINDOWS NATIVE
  CMake configuration completed successfully.
  Building NuttX...
MSBuild version 17.14.23+b0019275e for .NET Framework

  1>Checking Build System
  Building Custom Rule D:/a/nuttx/nuttx/sources/nuttx/CMakeLists.txt
  Building Custom Rule D:/a/nuttx/nuttx/sources/nuttx/CMakeLists.txt
  Building Custom Rule D:/a/nuttx/nuttx/sources/nuttx/CMakeLists.txt
cl : command line  warning D9002: ignoring unknown option '-fvisibility=default' [D:\a\nuttx\nuttx\sources\nuttx\build\sim_head.vcxproj]
  sim_head.c
  sim_doirq.c
  Generating Code...
D:\a\nuttx\nuttx\sources\nuttx\include\nuttx\macro.h(54,18): error C2010: '.': unexpected in macro parameter list [D:\a\nuttx\nuttx\sources\nuttx\build\sim_head.vcxproj]
  (compiling source file '../arch/sim/src/sim/sim_head.c')
  
D:\a\nuttx\nuttx\sources\nuttx\include\nuttx\macro.h(55,17): error C2010: '.': unexpected in macro parameter list [D:\a\nuttx\nuttx\sources\nuttx\build\sim_head.vcxproj]
  (compiling source file '../arch/sim/src/sim/sim_head.c')
  
D:\a\nuttx\nuttx\sources\nuttx\include\nuttx\macro.h(54,18): error C2010: '.': unexpected in macro parameter list [D:\a\nuttx\nuttx\sources\nuttx\build\sim_head.vcxproj]
  (compiling source file '../arch/sim/src/sim/sim_doirq.c')
  
D:\a\nuttx\nuttx\sources\nuttx\include\nuttx\macro.h(55,17): error C2010: '.': unexpected in macro parameter list [D:\a\nuttx\nuttx\sources\nuttx\build\sim_head.vcxproj]
  (compiling source file '../arch/sim/src/sim/sim_doirq.c')
  
  An error occurred while copying files: Cannot find path 'D:\a\nuttx\nuttx\sources\nuttx\build\Debug\nuttx.exe' because it does not exist.
  Refresh completed successfully.
------------------------------------------------------------------------------------
End: 2026-01-21 13:30:14
====================================================================================
Error: Process completed with exit code 1.