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Kernel: optimize yielding

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Doing a yield no longer raises a software interrupt. Instead it just
saves all the callee saved registers, ip, sp and return value. Because
yield is only called in the kernel, it can just restore registers and
jump to the target address. There is never a need to use iret :)
This commit is contained in:
Bananymous
2026-01-11 01:31:09 +02:00
parent 83e5cb81e8
commit 35c97e2ff8
13 changed files with 109 additions and 118 deletions
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49
kernel/kernel/Thread.cpp
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@@ -26,7 +26,7 @@ namespace Kernel
extern "C" uintptr_t get_thread_start_sp()
{
return Thread::current().interrupt_stack().sp;
return Thread::current().yield_registers().sp;
}
extern "C" void load_thread_sse()
@@ -179,13 +179,9 @@ namespace Kernel
write_to_stack(sp, data);
write_to_stack(sp, entry);
thread->m_interrupt_stack.ip = reinterpret_cast<vaddr_t>(start_kernel_thread);
thread->m_interrupt_stack.cs = 0x08;
thread->m_interrupt_stack.flags = 0x002;
thread->m_interrupt_stack.sp = sp;
thread->m_interrupt_stack.ss = 0x10;
memset(&thread->m_interrupt_registers, 0, sizeof(InterruptRegisters));
thread->m_yield_registers = {};
thread->m_yield_registers.ip = reinterpret_cast<vaddr_t>(start_kernel_thread);
thread->m_yield_registers.sp = sp;
thread_deleter.disable();
@@ -347,20 +343,13 @@ namespace Kernel
thread->m_state = State::NotStarted;
thread->m_interrupt_stack.ip = ip;
thread->m_interrupt_stack.cs = 0x08;
thread->m_interrupt_stack.flags = 0x002;
thread->m_interrupt_stack.sp = sp;
thread->m_interrupt_stack.ss = 0x10;
save_sse();
memcpy(thread->m_sse_storage, m_sse_storage, sizeof(m_sse_storage));
#if ARCH(x86_64)
thread->m_interrupt_registers.rax = 0;
#elif ARCH(i686)
thread->m_interrupt_registers.eax = 0;
#endif
thread->m_yield_registers = {};
thread->m_yield_registers.ip = ip;
thread->m_yield_registers.sp = sp;
thread->m_yield_registers.ret = 0;
thread_deleter.disable();
@@ -498,13 +487,9 @@ namespace Kernel
write_to_stack(cur_sp, ip);
});
m_interrupt_stack.ip = reinterpret_cast<vaddr_t>(start_userspace_thread);
m_interrupt_stack.cs = 0x08;
m_interrupt_stack.flags = 0x002;
m_interrupt_stack.sp = kernel_stack_top() - 5 * sizeof(uintptr_t);
m_interrupt_stack.ss = 0x10;
memset(&m_interrupt_registers, 0, sizeof(InterruptRegisters));
m_yield_registers = {};
m_yield_registers.ip = reinterpret_cast<vaddr_t>(start_userspace_thread);
m_yield_registers.sp = kernel_stack_top() - 5 * sizeof(uintptr_t);
}
void Thread::setup_process_cleanup()
@@ -539,13 +524,9 @@ namespace Kernel
write_to_stack(sp, entry);
});
m_interrupt_stack.ip = reinterpret_cast<vaddr_t>(start_kernel_thread);
m_interrupt_stack.cs = 0x08;
m_interrupt_stack.flags = 0x002;
m_interrupt_stack.sp = kernel_stack_top() - 4 * sizeof(uintptr_t);
m_interrupt_stack.ss = 0x10;
memset(&m_interrupt_registers, 0, sizeof(InterruptRegisters));
m_yield_registers = {};
m_yield_registers.ip = reinterpret_cast<vaddr_t>(start_kernel_thread);
m_yield_registers.sp = kernel_stack_top() - 4 * sizeof(uintptr_t);
}
bool Thread::is_interrupted_by_signal(bool skip_stop_and_cont) const
@@ -811,7 +792,7 @@ namespace Kernel
const vaddr_t stack_bottom = reinterpret_cast<vaddr_t>(m_signal_alt_stack.ss_sp);
const vaddr_t stack_top = stack_bottom + m_signal_alt_stack.ss_size;
const vaddr_t sp = m_interrupt_stack.sp;
const vaddr_t sp = m_yield_registers.sp;
return stack_bottom <= sp && sp <= stack_top;
}