zephyr/subsys
Stephanos Ioannidis 2d7460482d headers: Refactor kernel and arch headers.
This commit refactors kernel and arch headers to establish a boundary
between private and public interface headers.

The refactoring strategy used in this commit is detailed in the issue

This commit introduces the following major changes:

1. Establish a clear boundary between private and public headers by
  removing "kernel/include" and "arch/*/include" from the global
  include paths. Ideally, only kernel/ and arch/*/ source files should
  reference the headers in these directories. If these headers must be
  used by a component, these include paths shall be manually added to
  the CMakeLists.txt file of the component. This is intended to
  discourage applications from including private kernel and arch
  headers either knowingly and unknowingly.

  - kernel/include/ (PRIVATE)
    This directory contains the private headers that provide private
   kernel definitions which should not be visible outside the kernel
   and arch source code. All public kernel definitions must be added
   to an appropriate header located under include/.

  - arch/*/include/ (PRIVATE)
    This directory contains the private headers that provide private
   architecture-specific definitions which should not be visible
   outside the arch and kernel source code. All public architecture-
   specific definitions must be added to an appropriate header located
   under include/arch/*/.

  - include/ AND include/sys/ (PUBLIC)
    This directory contains the public headers that provide public
   kernel definitions which can be referenced by both kernel and
   application code.

  - include/arch/*/ (PUBLIC)
    This directory contains the public headers that provide public
   architecture-specific definitions which can be referenced by both
   kernel and application code.

2. Split arch_interface.h into "kernel-to-arch interface" and "public
  arch interface" divisions.

  - kernel/include/kernel_arch_interface.h
    * provides private "kernel-to-arch interface" definition.
    * includes arch/*/include/kernel_arch_func.h to ensure that the
     interface function implementations are always available.
    * includes sys/arch_interface.h so that public arch interface
     definitions are automatically included when including this file.

  - arch/*/include/kernel_arch_func.h
    * provides architecture-specific "kernel-to-arch interface"
     implementation.
    * only the functions that will be used in kernel and arch source
     files are defined here.

  - include/sys/arch_interface.h
    * provides "public arch interface" definition.
    * includes include/arch/arch_inlines.h to ensure that the
     architecture-specific public inline interface function
     implementations are always available.

  - include/arch/arch_inlines.h
    * includes architecture-specific arch_inlines.h in
     include/arch/*/arch_inline.h.

  - include/arch/*/arch_inline.h
    * provides architecture-specific "public arch interface" inline
     function implementation.
    * supersedes include/sys/arch_inline.h.

3. Refactor kernel and the existing architecture implementations.

  - Remove circular dependency of kernel and arch headers. The
   following general rules should be observed:

    * Never include any private headers from public headers
    * Never include kernel_internal.h in kernel_arch_data.h
    * Always include kernel_arch_data.h from kernel_arch_func.h
    * Never include kernel.h from kernel_struct.h either directly or
     indirectly. Only add the kernel structures that must be referenced
     from public arch headers in this file.

  - Relocate syscall_handler.h to include/ so it can be used in the
   public code. This is necessary because many user-mode public codes
   reference the functions defined in this header.

  - Relocate kernel_arch_thread.h to include/arch/*/thread.h. This is
   necessary to provide architecture-specific thread definition for
   'struct k_thread' in kernel.h.

  - Remove any private header dependencies from public headers using
   the following methods:

    * If dependency is not required, simply omit
    * If dependency is required,
      - Relocate a portion of the required dependencies from the
       private header to an appropriate public header OR
      - Relocate the required private header to make it public.

This commit supersedes #20047, addresses #19666, and fixes #3056.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2019-11-06 16:07:32 -08:00
..
bluetooth Bluetooth: Reduce severity of unavoidable warnings 2019-11-06 19:24:32 +02:00
console kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
cpp kconfig: cpp: Have LIB_CPLUSPLUS depend on ! MINIMAL_LIBC 2019-11-05 16:19:27 +01:00
debug headers: Refactor kernel and arch headers. 2019-11-06 16:07:32 -08:00
dfu flash_img: add error check to 'flash_progressive_erase' 2019-11-06 21:41:14 +01:00
disk kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
fb kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
fs kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
jwt kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
logging headers: Refactor kernel and arch headers. 2019-11-06 16:07:32 -08:00
mgmt kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
net headers: Refactor kernel and arch headers. 2019-11-06 16:07:32 -08:00
power cleanup: include/: move misc/reboot.h to power/reboot.h 2019-06-27 22:55:49 -04:00
random subsys/random: Add cryptographically secure and bulk fill functions 2019-11-05 19:36:42 +01:00
settings kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
shell kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
stats cleanup: include/: move stats.h to stats/stats.h 2019-06-27 22:55:49 -04:00
storage kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
testsuite headers: Refactor kernel and arch headers. 2019-11-06 16:07:32 -08:00
usb kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
CMakeLists.txt license: cleanup: add SPDX Apache-2.0 license identifier 2019-04-07 08:45:22 -04:00
Kconfig kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00