Kernel: Improve multithreading support

We can now use arbitary BAN::function<void(...)> as the Thread.
I also implemented multithreading for i386 since it was not done
on the initial multithreading commit.
This commit is contained in:
Bananymous 2023-02-02 23:24:12 +02:00
parent 777ede328e
commit 5b5e620d8a
8 changed files with 158 additions and 88 deletions

38
kernel/arch/i386/Thread.S Normal file
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@ -0,0 +1,38 @@
# uint32_t read_rip()
.global read_rip
read_rip:
popl %eax
jmp *%eax
exit_thread_trampoline:
addl $16, %esp
popl %eax
pushl $0x696969
pushl %eax
ret
# void start_thread(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint32_t arg3, uint32_t rsp, uint32_t rbp, uint32_t rip)
.global start_thread
start_thread:
movl %esp, %eax
movl 28(%eax), %ecx
movl 24(%eax), %ebp
movl 20(%eax), %esp
pushl 16(%eax)
pushl 12(%eax)
pushl 8(%eax)
pushl 4(%eax)
pushl $exit_thread_trampoline
sti
jmp *%ecx
# void continue_thread(uint32_t rsp, uint32_t rbp, uint32_t rip)
.global continue_thread
continue_thread:
movl 12(%esp), %ecx
movl 8(%esp), %ebp
movl 4(%esp), %esp
movl $0, %eax
jmp *%ecx

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@ -8,4 +8,5 @@ $(ARCHDIR)/boot.o \
$(ARCHDIR)/IDT.o \
$(ARCHDIR)/MMU.o \
$(ARCHDIR)/SpinLock.o \
$(ARCHDIR)/Thread.o \

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@ -0,0 +1,32 @@
# uint64_t read_rip()
.global read_rip
read_rip:
popq %rax
jmp *%rax
.global get_thread_at_exit
get_thread_at_exit:
movq 8(%rdi), %rax
ret
exit_thread_trampoline:
movq 8(%rsp), %rdi
ret
# void start_thread(uint64_t arg0, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t rsp, uint64_t rbp, uint64_t rip)
.global start_thread
start_thread:
movq 8(%rsp), %rcx
movq %r8, %rsp
movq %r9, %rbp
pushq $exit_thread_trampoline
sti
jmp *%rcx
# void continue_thread(uint64_t rsp, uint64_t rbp, uint64_t rip)
.global continue_thread
continue_thread:
movq %rdi, %rsp
movq %rsi, %rbp
movq $0, %rax
jmp *%rdx

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@ -9,4 +9,5 @@ $(ARCHDIR)/IDT.o \
$(ARCHDIR)/interrupts.o \
$(ARCHDIR)/MMU.o \
$(ARCHDIR)/SpinLock.o \
$(ARCHDIR)/Thread.o \

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@ -13,16 +13,26 @@ namespace Kernel
BAN_NON_MOVABLE(Scheduler);
public:
static void Initialize();
static Scheduler& Get();
static void initialize();
static Scheduler& get();
const Thread& CurrentThread() const;
const Thread& current_thread() const;
void AddThread(void(*)());
void Switch();
void Start();
template<typename... Args>
void add_thread(const BAN::Function<void(Args...)>& func, Args... args)
{
uintptr_t flags;
asm volatile("pushf; pop %0" : "=r"(flags));
asm volatile("cli");
MUST(m_threads.emplace_back(func, BAN::forward<Args>(args)...));
if (flags & (1 << 9))
asm volatile("sti");
}
static constexpr size_t ms_between_switch = 4;
void switch_thread();
void start();
static constexpr size_t ms_between_switch = 1;
private:
Scheduler() {}

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@ -1,6 +1,7 @@
#pragma once
#include <BAN/Memory.h>
#include <BAN/Function.h>
#include <BAN/NoCopyMove.h>
namespace Kernel
{
@ -20,28 +21,45 @@ namespace Kernel
};
public:
Thread(void(*)());
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpmf-conversions"
template<typename... Args>
Thread(const BAN::Function<void(Args...)>& func, Args... args)
: Thread((uintptr_t)(void*)&BAN::Function<void(Args...)>::operator(), (uintptr_t)&func, ((uintptr_t)args)...)
{
static_assert(((BAN::is_integral_v<Args> || BAN::is_pointer_v<Args>) && ...));
}
#pragma GCC diagnostic pop
~Thread();
uint32_t id() const { return m_id; }
void set_rip(uintptr_t rip) { m_rip = rip; }
void set_rsp(uintptr_t rsp) { m_rsp = rsp; }
void set_rbp(uintptr_t rbp) { m_rbp = rbp; }
void set_rip(uintptr_t rip) { m_rip = rip; }
void set_state(State state) { m_state = state; }
uintptr_t rip() const { return m_rip; }
uintptr_t rsp() const { return m_rsp; }
uintptr_t rbp() const { return m_rbp; }
uintptr_t rip() const { return m_rip; }
State state() const { return m_state; }
const uintptr_t* args() const { return m_args; }
private:
static void on_exit();
Thread(uintptr_t rip, uintptr_t func, uintptr_t arg1 = 0, uintptr_t arg2 = 0, uintptr_t arg3 = 0);
void on_exit();
private:
void* m_stack_base = nullptr;
State m_state = State::NotStarted;
uintptr_t m_args[4] = {};
uintptr_t m_rip = 0;
uintptr_t m_rbp = 0;
uintptr_t m_rsp = 0;
const uint32_t m_id = 0;
alignas(max_align_t) uint8_t m_function[BAN::Function<void()>::size()] { 0 };
};
}

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@ -7,18 +7,9 @@ namespace Kernel
static Scheduler* s_instance = nullptr;
extern "C" void start_thread(uintptr_t arg0, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t rsp, uintptr_t rbp, uintptr_t rip);
extern "C" void continue_thread(uintptr_t rsp, uintptr_t rbp, uintptr_t rip);
extern "C" uintptr_t read_rip();
asm(
".global read_rip;"
"read_rip:"
#if ARCH(x86_64)
"popq %rax;"
"jmp *%rax"
#else
"popl %eax;"
"jmp *%eax"
#endif
);
void Scheduler::initialize()
{
@ -37,13 +28,14 @@ namespace Kernel
return *m_current_iterator;
}
//void Scheduler::AddThread(const BAN::Function<void()>& function)
//{
// MUST(m_threads.EmplaceBack(function));
//}
void Scheduler::switch_thread()
{
uintptr_t rsp, rbp, rip;
if (!(rip = read_rip()))
return;
read_rsp(rsp);
read_rbp(rbp);
static uint8_t cnt = 0;
if (cnt++ % ms_between_switch)
return;
@ -63,6 +55,8 @@ namespace Kernel
Thread& current = *m_current_iterator;
Thread& next = *next_iterator;
ASSERT(next.state() == Thread::State::Paused || next.state() == Thread::State::NotStarted);
if (current.state() == Thread::State::Done)
{
// NOTE: this does not invalidate the next/next_iterator
@ -71,21 +65,11 @@ namespace Kernel
m_current_iterator = decltype(m_threads)::iterator();
}
uintptr_t rip = read_rip();
if (rip == 0)
return;
uintptr_t rsp;
#if ARCH(x86_64)
asm volatile("movq %%rsp, %0" : "=r"(rsp));
#else
asm volatile("movl %%esp, %0" : "=r"(rsp));
#endif
if (m_current_iterator)
{
current.set_rip(rip);
current.set_rsp(rsp);
current.set_rbp(rbp);
current.set_rip(rip);
current.set_state(Thread::State::Paused);
}
@ -93,33 +77,16 @@ namespace Kernel
if (next.state() == Thread::State::NotStarted)
{
InterruptController::Get().EOI(PIT_IRQ);
InterruptController::get().eoi(PIT_IRQ);
next.set_state(Thread::State::Running);
asm volatile(
#if ARCH(x86_64)
"movq %0, %%rsp;"
#else
"movl %0, %%esp;"
#endif
"sti;"
"jmp *%1;"
:: "r"(next.rsp()), "r"(next.rip())
);
const uintptr_t* args = next.args();
start_thread(args[0], args[1], args[2], args[3], next.rsp(), next.rbp(), next.rip());
}
else if (next.state() == Thread::State::Paused)
{
next.set_state(Thread::State::Running);
asm volatile(
#if ARCH(x86_64)
"movq %0, %%rsp;"
"movq $0, %%rax;"
#else
"movl %0, %%esp;"
"movl $0, %%eax;"
#endif
"jmp *%1;"
:: "r"(next.rsp()), "r"(next.rip())
);
BOCHS_BREAK();
continue_thread(next.rsp(), next.rbp(), next.rip());
}
ASSERT(false);
@ -134,16 +101,11 @@ namespace Kernel
Thread& current = *m_current_iterator;
ASSERT(current.state() == Thread::State::NotStarted);
current.set_state(Thread::State::Running);
asm volatile(
#if ARCH(x86_64)
"movq %0, %%rsp;"
#else
"movl %0, %%esp;"
#endif
"sti;"
"jmp *%1;"
:: "r"(current.rsp()), "r"(current.rip())
);
const uintptr_t* args = current.args();
start_thread(args[0], args[1], args[2], args[3], current.rsp(), current.rbp(), current.rip());
ASSERT(false);
}
}

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@ -14,23 +14,37 @@ namespace Kernel
static constexpr size_t thread_stack_size = PAGE_SIZE;
template<typename T>
template<size_t size, typename T>
static void write_to_stack(uintptr_t& rsp, const T& value)
{
rsp -= sizeof(T);
*(T*)rsp = value;
rsp -= size;
memcpy((void*)rsp, (void*)&value, size);
}
Thread::Thread(void(*function)())
Thread::Thread(uintptr_t rip, uintptr_t func, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3)
: m_id(s_next_id++)
{
m_stack_base = kmalloc(thread_stack_size, PAGE_SIZE);
ASSERT(m_stack_base);
m_rip = (uintptr_t)function;
m_rsp = (uintptr_t)m_stack_base + thread_stack_size;
write_to_stack(m_rsp, this);
write_to_stack(m_rsp, &Thread::on_exit);
m_rbp = (uintptr_t)m_stack_base + thread_stack_size;
m_rsp = m_rbp;
m_rip = rip;
m_args[1] = arg1;
m_args[2] = arg2;
m_args[3] = arg3;
// NOTE: in System V ABI arg0 is the pointer to 'this'
// we copy the function object to Thread object
// so we can ensure the lifetime of it. We store
// it as raw bytes so that Thread can be non-templated.
// This requires BAN::Function to be trivially copyable
// but for now it should be.
memcpy(m_function, (void*)func, sizeof(m_function));
m_args[0] = (uintptr_t)m_function;
write_to_stack<sizeof(void*)>(m_rsp, this);
write_to_stack<sizeof(void*)>(m_rsp, &Thread::on_exit);
}
Thread::~Thread()
@ -40,13 +54,7 @@ namespace Kernel
void Thread::on_exit()
{
Thread* thread = nullptr;
#if ARCH(x86_64)
asm volatile("movq (%%rsp), %0" : "=r"(thread));
#else
asm volatile("movl (%%esp), %0" : "=r"(thread));
#endif
thread->m_state = State::Done;
m_state = State::Done;
for (;;) asm volatile("hlt");
}