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Kernel: Implement initializing threads on x86_64

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This commit is contained in:
Gunnar Beutner 2021-06-27 13:59:41 +02:00 • committed by Andreas Kling
parent f285241cb8
commit 9ed051fe25
5 changed files with 59 additions and 44 deletions
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31
Kernel/Arch/x86/common/Processor.cpp
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@ -40,6 +40,10 @@ Atomic<u32> Processor::s_idle_cpu_mask { 0 };
extern "C" void thread_context_first_enter(void);
extern "C" void exit_kernel_thread(void);
// The compiler can't see the calls to this function inside assembly.
// Declare it, to avoid dead code warnings.
extern "C" void context_first_init(Thread* from_thread, Thread* to_thread, TrapFrame* trap) __attribute__((used));
UNMAP_AFTER_INIT static void sse_init()
{
write_cr0((read_cr0() & 0xfffffffbu) | 0x2);
@ -1134,4 +1138,31 @@ UNMAP_AFTER_INIT void Processor::gdt_init()
// clang-format on
#endif
}
extern "C" void context_first_init([[maybe_unused]] Thread* from_thread, [[maybe_unused]] Thread* to_thread, [[maybe_unused]] TrapFrame* trap)
{
VERIFY(!are_interrupts_enabled());
VERIFY(is_kernel_mode());
dbgln_if(CONTEXT_SWITCH_DEBUG, "switch_context <-- from {} {} to {} {} (context_first_init)", VirtualAddress(from_thread), *from_thread, VirtualAddress(to_thread), *to_thread);
VERIFY(to_thread == Thread::current());
Scheduler::enter_current(*from_thread, true);
// Since we got here and don't have Scheduler::context_switch in the
// call stack (because this is the first time we switched into this
// context), we need to notify the scheduler so that it can release
// the scheduler lock. We don't want to enable interrupts at this point
// as we're still in the middle of a context switch. Doing so could
// trigger a context switch within a context switch, leading to a crash.
FlatPtr flags;
#if ARCH(I386)
flags = trap->regs->eflags;
#else
flags = trap->regs->rflags;
#endif
Scheduler::leave_on_first_switch(flags & ~0x200);
}
}