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Kernel/SMP: Make entering/leaving critical sections multi-processor safe

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By making these functions static we close a window where we could get
preempted after calling Processor::current() and move to another
processor.

Co-authored-by: Tom <tomut@yahoo.com>
This commit is contained in:
Andreas Kling 2021-08-10 01:16:08 +02:00
parent 369e3da6a2
commit 9babb92a4b
11 changed files with 82 additions and 53 deletions
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12
Kernel/Syscalls/execve.cpp
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@ -297,7 +297,7 @@ static KResultOr<LoadResult> load_elf_object(NonnullOwnPtr<Memory::AddressSpace>
FlatPtr load_base_address = 0;
String elf_name = object_description.absolute_path();
VERIFY(!Processor::current().in_critical());
VERIFY(!Processor::in_critical());
Memory::MemoryManager::enter_space(*new_space);
@ -495,7 +495,7 @@ KResult Process::do_exec(NonnullRefPtr<FileDescription> main_program_description
RefPtr<FileDescription> interpreter_description, Thread*& new_main_thread, u32& prev_flags, const ElfW(Ehdr) & main_program_header)
{
VERIFY(is_user_process());
VERIFY(!Processor::current().in_critical());
VERIFY(!Processor::in_critical());
auto path = main_program_description->absolute_path();
dbgln_if(EXEC_DEBUG, "do_exec: {}", path);
@ -686,7 +686,7 @@ KResult Process::do_exec(NonnullRefPtr<FileDescription> main_program_description
u32 lock_count_to_restore;
[[maybe_unused]] auto rc = big_lock().force_unlock_if_locked(lock_count_to_restore);
VERIFY_INTERRUPTS_DISABLED();
VERIFY(Processor::current().in_critical());
VERIFY(Processor::in_critical());
return KSuccess;
}
@ -912,7 +912,7 @@ KResult Process::exec(String path, Vector<String> arguments, Vector<String> envi
return result;
VERIFY_INTERRUPTS_DISABLED();
VERIFY(Processor::current().in_critical());
VERIFY(Processor::in_critical());
auto current_thread = Thread::current();
if (current_thread == new_main_thread) {
@ -920,14 +920,14 @@ KResult Process::exec(String path, Vector<String> arguments, Vector<String> envi
// and it will be released after the context switch into that
// thread. We should also still be in our critical section
VERIFY(!g_scheduler_lock.own_lock());
VERIFY(Processor::current().in_critical() == 1);
VERIFY(Processor::in_critical() == 1);
g_scheduler_lock.lock();
current_thread->set_state(Thread::State::Running);
Processor::assume_context(*current_thread, prev_flags);
VERIFY_NOT_REACHED();
}
Processor::current().leave_critical(prev_flags);
Processor::leave_critical(prev_flags);
return KSuccess;
}