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Kernel: Turn lock ranks into template parameters

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This step would ideally not have been necessary (increases amount of
refactoring and templates necessary, which in turn increases build
times), but it gives us a couple of nice properties:
- SpinlockProtected inside Singleton (a very common combination) can now
  obtain any lock rank just via the template parameter. It was not
  previously possible to do this with SingletonInstanceCreator magic.
- SpinlockProtected's lock rank is now mandatory; this is the majority
  of cases and allows us to see where we're still missing proper ranks.
- The type already informs us what lock rank a lock has, which aids code
  readability and (possibly, if gdb cooperates) lock mismatch debugging.
- The rank of a lock can no longer be dynamic, which is not something we
  wanted in the first place (or made use of). Locks randomly changing
  their rank sounds like a disaster waiting to happen.
- In some places, we might be able to statically check that locks are
  taken in the right order (with the right lock rank checking
  implementation) as rank information is fully statically known.

This refactoring even more exposes the fact that Mutex has no lock rank
capabilites, which is not fixed here.
This commit is contained in:
kleines Filmröllchen 2022-11-09 11:39:58 +01:00 • committed by Brian Gianforcaro
parent 363cc12146
commit a6a439243f
94 changed files with 235 additions and 259 deletions
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16
Kernel/Process.cpp
View file

@ -46,9 +46,9 @@ static void create_signal_trampoline();
extern ProcessID g_init_pid;
RecursiveSpinlock g_profiling_lock { LockRank::None };
RecursiveSpinlock<LockRank::None> g_profiling_lock {};
static Atomic<pid_t> next_pid;
static Singleton<SpinlockProtected<Process::List>> s_all_instances;
static Singleton<SpinlockProtected<Process::List, LockRank::None>> s_all_instances;
READONLY_AFTER_INIT Memory::Region* g_signal_trampoline_region;
static Singleton<MutexProtected<OwnPtr<KString>>> s_hostname;
@ -58,7 +58,7 @@ MutexProtected<OwnPtr<KString>>& hostname()
return *s_hostname;
}
SpinlockProtected<Process::List>& Process::all_instances()
SpinlockProtected<Process::List, LockRank::None>& Process::all_instances()
{
return *s_all_instances;
}
@ -319,14 +319,12 @@ ErrorOr<NonnullLockRefPtr<Process>> Process::try_create(LockRefPtr<Thread>& firs
Process::Process(NonnullOwnPtr<KString> name, NonnullRefPtr<Credentials> credentials, ProcessID ppid, bool is_kernel_process, RefPtr<Custody> current_directory, RefPtr<Custody> executable, TTY* tty, UnveilNode unveil_tree, UnveilNode exec_unveil_tree)
: m_name(move(name))
, m_space(LockRank::None)
, m_protected_data_lock(LockRank::None)
, m_is_kernel_process(is_kernel_process)
, m_executable(LockRank::None, move(executable))
, m_current_directory(LockRank::None, move(current_directory))
, m_executable(move(executable))
, m_current_directory(move(current_directory))
, m_tty(tty)
, m_unveil_data(LockRank::None, move(unveil_tree))
, m_exec_unveil_data(LockRank::None, move(exec_unveil_tree))
, m_unveil_data(move(unveil_tree))
, m_exec_unveil_data(move(exec_unveil_tree))
, m_wait_blocker_set(*this)
{
// Ensure that we protect the process data when exiting the constructor.