[kernel][mutex] Make mutex_t use constructors/destructors.

Take a baby step in the direction of making mutex_t more C++ and less
C.  Specifically...

++ Remove mutex_init
++ Remove mutex_destroy
++ Remove the MUTEX_INITIAL_VALUE { .member = ... } initializer macro
++ Wire up a constexpr default constructor which does what mutex_init
   and MUTEX_INITAL_VALUE used to do.
++ Wire up a destructor which does what mutex_destroy used to do.

I have verified (by manual inspection) that our current debug builds
(for clang and ASAN) are still performing initialization of globals
and static locals using just .data segment initialization.  There is a
separate discussion going on about how to ensure that this behavior
remains safe moving forward from the static local perspective.

This change is a small step in the direction of allowing us to turn
this code into a full C++ implementation (from a style perspective).
Eventually, we can use this as part of the process to to remove any of
the #ifdef KERNEL stuff from fbl::AutoLock, and to migrate the
kernel's RAII lock object over completely to lockdep::Guard instead.

Tests: Built for x64 and arm64 (ASAN builds).
       "k ut all" and "k thread_tests" in QEMU for both architectures.
Change-Id: Ic97d83c790d4297fabb0997baf0b1d9bc94fa9b6
12 files changed
tree: 56788c63f95bc310b3886285c32f32456bfc4241
  1. bootloader/
  2. docs/
  3. kernel/
  4. make/
  5. prebuilt/
  6. public/
  7. scripts/
  8. system/
  9. third_party/
  10. .clang-format
  11. .clang-tidy
  12. .dir-locals.el
  13. .gitignore
  14. .travis.yml
  15. AUTHORS
  16. LICENSE
  17. MAINTAINERS
  18. makefile
  19. navbar.md
  20. PATENTS
  21. README.md
README.md

Zircon

Zircon is the core platform that powers the Fuchsia OS. Zircon is composed of a microkernel (source in kernel/...) as well as a small set of userspace services, drivers, and libraries (source in system/...) necessary for the system to boot, talk to hardware, load userspace processes and run them, etc. Fuchsia builds a much larger OS on top of this foundation.

The canonical Zircon Git repository is located at: https://fuchsia.googlesource.com/zircon

A read-only mirror of the code is present at: https://github.com/fuchsia-mirror/zircon

The Zircon Kernel provides syscalls to manage processes, threads, virtual memory, inter-process communication, waiting on object state changes, and locking (via futexes).

Currently there are some temporary syscalls that have been used for early bringup work, which will be going away in the future as the long term syscall API/ABI surface is finalized. The expectation is that there will be about 100 syscalls.

Zircon syscalls are generally non-blocking. The wait_one, wait_many port_wait and thread sleep being the notable exceptions.

This page is a non-comprehensive index of the zircon documentation.