11496ba7bSLoGin use core::{ 21496ba7bSLoGin arch::asm, 31496ba7bSLoGin intrinsics::unlikely, 41496ba7bSLoGin mem::ManuallyDrop, 51496ba7bSLoGin sync::atomic::{compiler_fence, Ordering}, 61496ba7bSLoGin }; 71496ba7bSLoGin 8971462beSGnoCiYeH use alloc::{ 9971462beSGnoCiYeH string::String, 10971462beSGnoCiYeH sync::{Arc, Weak}, 11971462beSGnoCiYeH vec::Vec, 12971462beSGnoCiYeH }; 131496ba7bSLoGin 147b32f508SLoGin use kdepends::memoffset::offset_of; 15*91e9d4abSLoGin use system_error::SystemError; 161496ba7bSLoGin use x86::{controlregs::Cr4, segmentation::SegmentSelector}; 171496ba7bSLoGin 181496ba7bSLoGin use crate::{ 191496ba7bSLoGin arch::process::table::TSSManager, 201496ba7bSLoGin exception::InterruptArch, 214fda81ceSLoGin kerror, kwarn, 221496ba7bSLoGin libs::spinlock::SpinLockGuard, 231496ba7bSLoGin mm::{ 241496ba7bSLoGin percpu::{PerCpu, PerCpuVar}, 251496ba7bSLoGin VirtAddr, 261496ba7bSLoGin }, 271496ba7bSLoGin process::{ 28971462beSGnoCiYeH fork::{CloneFlags, KernelCloneArgs}, 29971462beSGnoCiYeH KernelStack, ProcessControlBlock, ProcessFlags, ProcessManager, SwitchResult, 30971462beSGnoCiYeH SWITCH_RESULT, 311496ba7bSLoGin }, 32*91e9d4abSLoGin syscall::Syscall, 331496ba7bSLoGin }; 341496ba7bSLoGin 351496ba7bSLoGin use self::{ 361496ba7bSLoGin kthread::kernel_thread_bootstrap_stage1, 37971462beSGnoCiYeH syscall::ARCH_SET_FS, 381496ba7bSLoGin table::{switch_fs_and_gs, KERNEL_DS, USER_DS}, 391496ba7bSLoGin }; 401496ba7bSLoGin 4116033951SGnoCiYeH use super::{fpu::FpState, interrupt::TrapFrame, syscall::X86_64GSData, CurrentIrqArch}; 421496ba7bSLoGin 431496ba7bSLoGin mod c_adapter; 441496ba7bSLoGin pub mod kthread; 451496ba7bSLoGin pub mod syscall; 461496ba7bSLoGin pub mod table; 471496ba7bSLoGin 481496ba7bSLoGin extern "C" { 491496ba7bSLoGin /// 从中断返回 501496ba7bSLoGin fn ret_from_intr(); 511496ba7bSLoGin } 521496ba7bSLoGin 53de71ec25SLoGin #[allow(dead_code)] 54de71ec25SLoGin #[repr(align(32768))] 55de71ec25SLoGin union InitProcUnion { 56de71ec25SLoGin /// 用于存放idle进程的内核栈 57de71ec25SLoGin idle_stack: [u8; 32768], 58de71ec25SLoGin } 59de71ec25SLoGin 60de71ec25SLoGin #[link_section = ".data.init_proc_union"] 61de71ec25SLoGin #[no_mangle] 62de71ec25SLoGin static BSP_IDLE_STACK_SPACE: InitProcUnion = InitProcUnion { 63de71ec25SLoGin idle_stack: [0; 32768], 64de71ec25SLoGin }; 65de71ec25SLoGin 661496ba7bSLoGin /// PCB中与架构相关的信息 6716033951SGnoCiYeH #[derive(Debug)] 681496ba7bSLoGin #[allow(dead_code)] 691496ba7bSLoGin pub struct ArchPCBInfo { 701496ba7bSLoGin rflags: usize, 711496ba7bSLoGin rbx: usize, 721496ba7bSLoGin r12: usize, 731496ba7bSLoGin r13: usize, 741496ba7bSLoGin r14: usize, 751496ba7bSLoGin r15: usize, 761496ba7bSLoGin rbp: usize, 771496ba7bSLoGin rsp: usize, 781496ba7bSLoGin rip: usize, 791496ba7bSLoGin cr2: usize, 801496ba7bSLoGin fsbase: usize, 811496ba7bSLoGin gsbase: usize, 8216033951SGnoCiYeH fs: SegmentSelector, 8316033951SGnoCiYeH gs: SegmentSelector, 8416033951SGnoCiYeH /// 存储PCB系统调用栈以及在syscall过程中暂存用户态rsp的结构体 8516033951SGnoCiYeH gsdata: X86_64GSData, 861496ba7bSLoGin /// 浮点寄存器的状态 871496ba7bSLoGin fp_state: Option<FpState>, 881496ba7bSLoGin } 891496ba7bSLoGin 901496ba7bSLoGin #[allow(dead_code)] 911496ba7bSLoGin impl ArchPCBInfo { 921496ba7bSLoGin /// 创建一个新的ArchPCBInfo 931496ba7bSLoGin /// 941496ba7bSLoGin /// ## 参数 951496ba7bSLoGin /// 961496ba7bSLoGin /// - `kstack`:内核栈的引用,如果为None,则不会设置rsp和rbp。如果为Some,则会设置rsp和rbp为内核栈的最高地址。 971496ba7bSLoGin /// 981496ba7bSLoGin /// ## 返回值 991496ba7bSLoGin /// 1001496ba7bSLoGin /// 返回一个新的ArchPCBInfo 10116033951SGnoCiYeH pub fn new(kstack: &KernelStack) -> Self { 1021496ba7bSLoGin let mut r = Self { 1031496ba7bSLoGin rflags: 0, 1041496ba7bSLoGin rbx: 0, 1051496ba7bSLoGin r12: 0, 1061496ba7bSLoGin r13: 0, 1071496ba7bSLoGin r14: 0, 1081496ba7bSLoGin r15: 0, 1091496ba7bSLoGin rbp: 0, 1101496ba7bSLoGin rsp: 0, 1111496ba7bSLoGin rip: 0, 1121496ba7bSLoGin cr2: 0, 1131496ba7bSLoGin fsbase: 0, 1141496ba7bSLoGin gsbase: 0, 11516033951SGnoCiYeH gsdata: X86_64GSData { 11616033951SGnoCiYeH kaddr: VirtAddr::new(0), 11716033951SGnoCiYeH uaddr: VirtAddr::new(0), 11816033951SGnoCiYeH }, 11916033951SGnoCiYeH fs: KERNEL_DS, 12016033951SGnoCiYeH gs: KERNEL_DS, 1211496ba7bSLoGin fp_state: None, 1221496ba7bSLoGin }; 1231496ba7bSLoGin 12416033951SGnoCiYeH r.rsp = kstack.stack_max_address().data() - 8; 1251496ba7bSLoGin r.rbp = kstack.stack_max_address().data(); 1261496ba7bSLoGin 1271496ba7bSLoGin return r; 1281496ba7bSLoGin } 1291496ba7bSLoGin 1301496ba7bSLoGin pub fn set_stack(&mut self, stack: VirtAddr) { 1311496ba7bSLoGin self.rsp = stack.data(); 1321496ba7bSLoGin } 1331496ba7bSLoGin 1341496ba7bSLoGin pub fn set_stack_base(&mut self, stack_base: VirtAddr) { 1351496ba7bSLoGin self.rbp = stack_base.data(); 1361496ba7bSLoGin } 1371496ba7bSLoGin 1381496ba7bSLoGin pub fn rbp(&self) -> usize { 1391496ba7bSLoGin self.rbp 1401496ba7bSLoGin } 1411496ba7bSLoGin 1421496ba7bSLoGin pub unsafe fn push_to_stack(&mut self, value: usize) { 1431496ba7bSLoGin self.rsp -= core::mem::size_of::<usize>(); 1441496ba7bSLoGin *(self.rsp as *mut usize) = value; 1451496ba7bSLoGin } 1461496ba7bSLoGin 1471496ba7bSLoGin pub unsafe fn pop_from_stack(&mut self) -> usize { 1481496ba7bSLoGin let value = *(self.rsp as *const usize); 1491496ba7bSLoGin self.rsp += core::mem::size_of::<usize>(); 1501496ba7bSLoGin value 1511496ba7bSLoGin } 1521496ba7bSLoGin 1531496ba7bSLoGin pub fn save_fp_state(&mut self) { 1541496ba7bSLoGin if self.fp_state.is_none() { 1551496ba7bSLoGin self.fp_state = Some(FpState::new()); 1561496ba7bSLoGin } 1571496ba7bSLoGin 1581496ba7bSLoGin self.fp_state.as_mut().unwrap().save(); 1591496ba7bSLoGin } 1601496ba7bSLoGin 1611496ba7bSLoGin pub fn restore_fp_state(&mut self) { 1621496ba7bSLoGin if unlikely(self.fp_state.is_none()) { 1631496ba7bSLoGin return; 1641496ba7bSLoGin } 1651496ba7bSLoGin 1661496ba7bSLoGin self.fp_state.as_mut().unwrap().restore(); 1671496ba7bSLoGin } 1681496ba7bSLoGin 1693c82aa56SChiichen /// 返回浮点寄存器结构体的副本 1703c82aa56SChiichen pub fn fp_state(&self) -> &Option<FpState> { 1713c82aa56SChiichen &self.fp_state 1723c82aa56SChiichen } 1733c82aa56SChiichen 1743c82aa56SChiichen // 清空浮点寄存器 1753c82aa56SChiichen pub fn clear_fp_state(&mut self) { 1763c82aa56SChiichen if unlikely(self.fp_state.is_none()) { 1773c82aa56SChiichen kwarn!("fp_state is none"); 1783c82aa56SChiichen return; 1793c82aa56SChiichen } 1803c82aa56SChiichen 1813c82aa56SChiichen self.fp_state.as_mut().unwrap().clear(); 1823c82aa56SChiichen } 1831496ba7bSLoGin pub unsafe fn save_fsbase(&mut self) { 1841496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) { 1851496ba7bSLoGin self.fsbase = x86::current::segmentation::rdfsbase() as usize; 1861496ba7bSLoGin } else { 18716033951SGnoCiYeH self.fsbase = x86::msr::rdmsr(x86::msr::IA32_FS_BASE) as usize; 1881496ba7bSLoGin } 1891496ba7bSLoGin } 1901496ba7bSLoGin 1911496ba7bSLoGin pub unsafe fn save_gsbase(&mut self) { 1921496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) { 1931496ba7bSLoGin self.gsbase = x86::current::segmentation::rdgsbase() as usize; 1941496ba7bSLoGin } else { 19516033951SGnoCiYeH self.gsbase = x86::msr::rdmsr(x86::msr::IA32_GS_BASE) as usize; 1961496ba7bSLoGin } 1971496ba7bSLoGin } 1981496ba7bSLoGin 1991496ba7bSLoGin pub unsafe fn restore_fsbase(&mut self) { 2001496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) { 2011496ba7bSLoGin x86::current::segmentation::wrfsbase(self.fsbase as u64); 202971462beSGnoCiYeH } else { 20316033951SGnoCiYeH x86::msr::wrmsr(x86::msr::IA32_FS_BASE, self.fsbase as u64); 2041496ba7bSLoGin } 2051496ba7bSLoGin } 2061496ba7bSLoGin 2071496ba7bSLoGin pub unsafe fn restore_gsbase(&mut self) { 2081496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) { 2091496ba7bSLoGin x86::current::segmentation::wrgsbase(self.gsbase as u64); 210971462beSGnoCiYeH } else { 21116033951SGnoCiYeH x86::msr::wrmsr(x86::msr::IA32_GS_BASE, self.gsbase as u64); 2121496ba7bSLoGin } 2131496ba7bSLoGin } 2141496ba7bSLoGin 21516033951SGnoCiYeH /// 将gsdata写入KernelGsbase寄存器 21616033951SGnoCiYeH pub unsafe fn store_kernel_gsbase(&self) { 21716033951SGnoCiYeH x86::msr::wrmsr( 21816033951SGnoCiYeH x86::msr::IA32_KERNEL_GSBASE, 21916033951SGnoCiYeH &self.gsdata as *const X86_64GSData as u64, 22016033951SGnoCiYeH ); 22116033951SGnoCiYeH } 22216033951SGnoCiYeH 22316033951SGnoCiYeH /// ### 初始化系统调用栈,不得与PCB内核栈冲突(即传入的应该是一个新的栈,避免栈损坏) 22416033951SGnoCiYeH pub fn init_syscall_stack(&mut self, stack: &KernelStack) { 22516033951SGnoCiYeH self.gsdata.set_kstack(stack.stack_max_address() - 8); 22616033951SGnoCiYeH } 22716033951SGnoCiYeH 2281496ba7bSLoGin pub fn fsbase(&self) -> usize { 2291496ba7bSLoGin self.fsbase 2301496ba7bSLoGin } 2311496ba7bSLoGin 2321496ba7bSLoGin pub fn gsbase(&self) -> usize { 2331496ba7bSLoGin self.gsbase 2341496ba7bSLoGin } 2353c82aa56SChiichen 2363c82aa56SChiichen pub fn cr2_mut(&mut self) -> &mut usize { 2373c82aa56SChiichen &mut self.cr2 2383c82aa56SChiichen } 2393c82aa56SChiichen 2403c82aa56SChiichen pub fn fp_state_mut(&mut self) -> &mut Option<FpState> { 2413c82aa56SChiichen &mut self.fp_state 2423c82aa56SChiichen } 24316033951SGnoCiYeH 24416033951SGnoCiYeH /// ### 克隆ArchPCBInfo,需要注意gsdata也是对应clone的 24516033951SGnoCiYeH pub fn clone_all(&self) -> Self { 24616033951SGnoCiYeH Self { 24716033951SGnoCiYeH rflags: self.rflags, 24816033951SGnoCiYeH rbx: self.rbx, 24916033951SGnoCiYeH r12: self.r12, 25016033951SGnoCiYeH r13: self.r13, 25116033951SGnoCiYeH r14: self.r14, 25216033951SGnoCiYeH r15: self.r15, 25316033951SGnoCiYeH rbp: self.rbp, 25416033951SGnoCiYeH rsp: self.rsp, 25516033951SGnoCiYeH rip: self.rip, 25616033951SGnoCiYeH cr2: self.cr2, 25716033951SGnoCiYeH fsbase: self.fsbase, 25816033951SGnoCiYeH gsbase: self.gsbase, 25916033951SGnoCiYeH fs: self.fs.clone(), 26016033951SGnoCiYeH gs: self.gs.clone(), 26116033951SGnoCiYeH gsdata: self.gsdata.clone(), 26216033951SGnoCiYeH fp_state: self.fp_state, 26316033951SGnoCiYeH } 26416033951SGnoCiYeH } 26516033951SGnoCiYeH 26616033951SGnoCiYeH // ### 从另一个ArchPCBInfo处clone,gsdata会被保留 26716033951SGnoCiYeH pub fn clone_from(&mut self, from: &Self) { 26816033951SGnoCiYeH let gsdata = self.gsdata.clone(); 26916033951SGnoCiYeH *self = from.clone_all(); 27016033951SGnoCiYeH self.gsdata = gsdata; 27116033951SGnoCiYeH } 2721496ba7bSLoGin } 2731496ba7bSLoGin 2741496ba7bSLoGin impl ProcessControlBlock { 2751496ba7bSLoGin /// 获取当前进程的pcb 2761496ba7bSLoGin pub fn arch_current_pcb() -> Arc<Self> { 2771496ba7bSLoGin // 获取栈指针 2781496ba7bSLoGin let ptr = VirtAddr::new(x86::current::registers::rsp() as usize); 2794fda81ceSLoGin 2801496ba7bSLoGin let stack_base = VirtAddr::new(ptr.data() & (!(KernelStack::ALIGN - 1))); 2814fda81ceSLoGin 2821496ba7bSLoGin // 从内核栈的最低地址处取出pcb的地址 2831496ba7bSLoGin let p = stack_base.data() as *const *const ProcessControlBlock; 2841496ba7bSLoGin if unlikely((unsafe { *p }).is_null()) { 2854fda81ceSLoGin kerror!("p={:p}", p); 2861496ba7bSLoGin panic!("current_pcb is null"); 2871496ba7bSLoGin } 2881496ba7bSLoGin unsafe { 289971462beSGnoCiYeH // 为了防止内核栈的pcb weak 指针被释放,这里需要将其包装一下 290971462beSGnoCiYeH let weak_wrapper: ManuallyDrop<Weak<ProcessControlBlock>> = 291971462beSGnoCiYeH ManuallyDrop::new(Weak::from_raw(*p)); 2921496ba7bSLoGin 293971462beSGnoCiYeH let new_arc: Arc<ProcessControlBlock> = weak_wrapper.upgrade().unwrap(); 2941496ba7bSLoGin return new_arc; 2951496ba7bSLoGin } 2961496ba7bSLoGin } 2971496ba7bSLoGin } 2981496ba7bSLoGin 2991496ba7bSLoGin impl ProcessManager { 3001496ba7bSLoGin pub fn arch_init() { 3011496ba7bSLoGin { 3021496ba7bSLoGin // 初始化进程切换结果 per cpu变量 3031496ba7bSLoGin let mut switch_res_vec: Vec<SwitchResult> = Vec::new(); 3041496ba7bSLoGin for _ in 0..PerCpu::MAX_CPU_NUM { 3051496ba7bSLoGin switch_res_vec.push(SwitchResult::new()); 3061496ba7bSLoGin } 3071496ba7bSLoGin unsafe { 3081496ba7bSLoGin SWITCH_RESULT = Some(PerCpuVar::new(switch_res_vec).unwrap()); 3091496ba7bSLoGin } 3101496ba7bSLoGin } 3111496ba7bSLoGin } 3121496ba7bSLoGin /// fork的过程中复制线程 3131496ba7bSLoGin /// 3141496ba7bSLoGin /// 由于这个过程与具体的架构相关,所以放在这里 3151496ba7bSLoGin pub fn copy_thread( 3161496ba7bSLoGin current_pcb: &Arc<ProcessControlBlock>, 3171496ba7bSLoGin new_pcb: &Arc<ProcessControlBlock>, 318971462beSGnoCiYeH clone_args: KernelCloneArgs, 3191496ba7bSLoGin current_trapframe: &TrapFrame, 3201496ba7bSLoGin ) -> Result<(), SystemError> { 321971462beSGnoCiYeH let clone_flags = clone_args.flags; 3221496ba7bSLoGin let mut child_trapframe = current_trapframe.clone(); 3231496ba7bSLoGin 3241496ba7bSLoGin // 子进程的返回值为0 3251496ba7bSLoGin child_trapframe.set_return_value(0); 3261496ba7bSLoGin 3271496ba7bSLoGin // 设置子进程的栈基址(开始执行中断返回流程时的栈基址) 3281496ba7bSLoGin let mut new_arch_guard = new_pcb.arch_info(); 3291496ba7bSLoGin let kernel_stack_guard = new_pcb.kernel_stack(); 3301496ba7bSLoGin 3311496ba7bSLoGin // 设置子进程在内核态开始执行时的rsp、rbp 3321496ba7bSLoGin new_arch_guard.set_stack_base(kernel_stack_guard.stack_max_address()); 3331496ba7bSLoGin 3341496ba7bSLoGin let trap_frame_vaddr: VirtAddr = 3351496ba7bSLoGin kernel_stack_guard.stack_max_address() - core::mem::size_of::<TrapFrame>(); 3361496ba7bSLoGin new_arch_guard.set_stack(trap_frame_vaddr); 3371496ba7bSLoGin 3381496ba7bSLoGin // 拷贝栈帧 3391496ba7bSLoGin unsafe { 340971462beSGnoCiYeH let usp = clone_args.stack; 341971462beSGnoCiYeH if usp != 0 { 342971462beSGnoCiYeH child_trapframe.rsp = usp as u64; 343971462beSGnoCiYeH } 3441496ba7bSLoGin let trap_frame_ptr = trap_frame_vaddr.data() as *mut TrapFrame; 3451496ba7bSLoGin *trap_frame_ptr = child_trapframe; 3461496ba7bSLoGin } 3471496ba7bSLoGin 3481496ba7bSLoGin let current_arch_guard = current_pcb.arch_info_irqsave(); 3491496ba7bSLoGin new_arch_guard.fsbase = current_arch_guard.fsbase; 3501496ba7bSLoGin new_arch_guard.gsbase = current_arch_guard.gsbase; 3511496ba7bSLoGin new_arch_guard.fs = current_arch_guard.fs; 3521496ba7bSLoGin new_arch_guard.gs = current_arch_guard.gs; 3531496ba7bSLoGin new_arch_guard.fp_state = current_arch_guard.fp_state.clone(); 3541496ba7bSLoGin 3551496ba7bSLoGin // 拷贝浮点寄存器的状态 3561496ba7bSLoGin if let Some(fp_state) = current_arch_guard.fp_state.as_ref() { 3571496ba7bSLoGin new_arch_guard.fp_state = Some(*fp_state); 3581496ba7bSLoGin } 3591496ba7bSLoGin drop(current_arch_guard); 3601496ba7bSLoGin 3611496ba7bSLoGin // 设置返回地址(子进程开始执行的指令地址) 3621496ba7bSLoGin if new_pcb.flags().contains(ProcessFlags::KTHREAD) { 3631496ba7bSLoGin let kthread_bootstrap_stage1_func_addr = kernel_thread_bootstrap_stage1 as usize; 3641496ba7bSLoGin new_arch_guard.rip = kthread_bootstrap_stage1_func_addr; 3651496ba7bSLoGin } else { 3661496ba7bSLoGin new_arch_guard.rip = ret_from_intr as usize; 3671496ba7bSLoGin } 3681496ba7bSLoGin 369971462beSGnoCiYeH // 设置tls 370971462beSGnoCiYeH if clone_flags.contains(CloneFlags::CLONE_SETTLS) { 371971462beSGnoCiYeH drop(new_arch_guard); 372971462beSGnoCiYeH Syscall::do_arch_prctl_64(new_pcb, ARCH_SET_FS, clone_args.tls, true)?; 373971462beSGnoCiYeH } 374971462beSGnoCiYeH 3751496ba7bSLoGin return Ok(()); 3761496ba7bSLoGin } 3771496ba7bSLoGin 3781496ba7bSLoGin /// 切换进程 3791496ba7bSLoGin /// 3801496ba7bSLoGin /// ## 参数 3811496ba7bSLoGin /// 3821496ba7bSLoGin /// - `prev`:上一个进程的pcb 3831496ba7bSLoGin /// - `next`:下一个进程的pcb 3841496ba7bSLoGin pub unsafe fn switch_process(prev: Arc<ProcessControlBlock>, next: Arc<ProcessControlBlock>) { 3851496ba7bSLoGin assert!(CurrentIrqArch::is_irq_enabled() == false); 3861496ba7bSLoGin 3871496ba7bSLoGin // 保存浮点寄存器 3881496ba7bSLoGin prev.arch_info().save_fp_state(); 3891496ba7bSLoGin // 切换浮点寄存器 3901496ba7bSLoGin next.arch_info().restore_fp_state(); 3911496ba7bSLoGin 3921496ba7bSLoGin // 切换fsbase 3931496ba7bSLoGin prev.arch_info().save_fsbase(); 3941496ba7bSLoGin next.arch_info().restore_fsbase(); 3951496ba7bSLoGin 3961496ba7bSLoGin // 切换gsbase 39716033951SGnoCiYeH Self::switch_gsbase(&prev, &next); 3981496ba7bSLoGin 3991496ba7bSLoGin // 切换地址空间 4001496ba7bSLoGin let next_addr_space = next.basic().user_vm().as_ref().unwrap().clone(); 4011496ba7bSLoGin compiler_fence(Ordering::SeqCst); 4021496ba7bSLoGin 4031496ba7bSLoGin next_addr_space.read().user_mapper.utable.make_current(); 404971462beSGnoCiYeH drop(next_addr_space); 4051496ba7bSLoGin compiler_fence(Ordering::SeqCst); 4061496ba7bSLoGin // 切换内核栈 4071496ba7bSLoGin 4081496ba7bSLoGin // 获取arch info的锁,并强制泄露其守卫(切换上下文后,在switch_finish_hook中会释放锁) 409971462beSGnoCiYeH let next_arch = SpinLockGuard::leak(next.arch_info()) as *mut ArchPCBInfo; 410971462beSGnoCiYeH let prev_arch = SpinLockGuard::leak(prev.arch_info()) as *mut ArchPCBInfo; 4111496ba7bSLoGin 412971462beSGnoCiYeH (*prev_arch).rip = switch_back as usize; 4131496ba7bSLoGin 4141496ba7bSLoGin // 恢复当前的 preempt count*2 4151496ba7bSLoGin ProcessManager::current_pcb().preempt_enable(); 4161496ba7bSLoGin ProcessManager::current_pcb().preempt_enable(); 4171496ba7bSLoGin 4181496ba7bSLoGin // 切换tss 4191496ba7bSLoGin TSSManager::current_tss().set_rsp( 4201496ba7bSLoGin x86::Ring::Ring0, 4211496ba7bSLoGin next.kernel_stack().stack_max_address().data() as u64, 4221496ba7bSLoGin ); 423971462beSGnoCiYeH SWITCH_RESULT.as_mut().unwrap().get_mut().prev_pcb = Some(prev); 424971462beSGnoCiYeH SWITCH_RESULT.as_mut().unwrap().get_mut().next_pcb = Some(next); 4251496ba7bSLoGin // kdebug!("switch tss ok"); 426de71ec25SLoGin compiler_fence(Ordering::SeqCst); 4271496ba7bSLoGin // 正式切换上下文 4281496ba7bSLoGin switch_to_inner(prev_arch, next_arch); 4291496ba7bSLoGin } 43016033951SGnoCiYeH 43116033951SGnoCiYeH unsafe fn switch_gsbase(prev: &Arc<ProcessControlBlock>, next: &Arc<ProcessControlBlock>) { 43216033951SGnoCiYeH asm!("swapgs", options(nostack, preserves_flags)); 43316033951SGnoCiYeH prev.arch_info().save_gsbase(); 43416033951SGnoCiYeH next.arch_info().restore_gsbase(); 43516033951SGnoCiYeH // 将下一个进程的kstack写入kernel_gsbase 43616033951SGnoCiYeH next.arch_info().store_kernel_gsbase(); 43716033951SGnoCiYeH asm!("swapgs", options(nostack, preserves_flags)); 43816033951SGnoCiYeH } 4391496ba7bSLoGin } 4401496ba7bSLoGin 4411496ba7bSLoGin /// 保存上下文,然后切换进程,接着jmp到`switch_finish_hook`钩子函数 4421496ba7bSLoGin #[naked] 443971462beSGnoCiYeH unsafe extern "sysv64" fn switch_to_inner(prev: *mut ArchPCBInfo, next: *mut ArchPCBInfo) { 4441496ba7bSLoGin asm!( 4451496ba7bSLoGin // As a quick reminder for those who are unfamiliar with the System V ABI (extern "C"): 4461496ba7bSLoGin // 4471496ba7bSLoGin // - the current parameters are passed in the registers `rdi`, `rsi`, 4481496ba7bSLoGin // - we can modify scratch registers, e.g. rax 4491496ba7bSLoGin // - we cannot change callee-preserved registers arbitrarily, e.g. rbx, which is why we 4501496ba7bSLoGin // store them here in the first place. 4511496ba7bSLoGin concat!(" 4521496ba7bSLoGin // Save old registers, and load new ones 4531496ba7bSLoGin mov [rdi + {off_rbx}], rbx 4541496ba7bSLoGin mov rbx, [rsi + {off_rbx}] 4551496ba7bSLoGin 4561496ba7bSLoGin mov [rdi + {off_r12}], r12 4571496ba7bSLoGin mov r12, [rsi + {off_r12}] 4581496ba7bSLoGin 4591496ba7bSLoGin mov [rdi + {off_r13}], r13 4601496ba7bSLoGin mov r13, [rsi + {off_r13}] 4611496ba7bSLoGin 4621496ba7bSLoGin mov [rdi + {off_r14}], r14 4631496ba7bSLoGin mov r14, [rsi + {off_r14}] 4641496ba7bSLoGin 4651496ba7bSLoGin mov [rdi + {off_r15}], r15 4661496ba7bSLoGin mov r15, [rsi + {off_r15}] 4671496ba7bSLoGin 4681496ba7bSLoGin // switch segment registers (这些寄存器只能通过接下来的switch_hook的return来切换) 4691496ba7bSLoGin mov [rdi + {off_fs}], fs 4701496ba7bSLoGin mov [rdi + {off_gs}], gs 4711496ba7bSLoGin 472971462beSGnoCiYeH // mov fs, [rsi + {off_fs}] 473971462beSGnoCiYeH // mov gs, [rsi + {off_gs}] 474971462beSGnoCiYeH 4751496ba7bSLoGin push rbp 4761496ba7bSLoGin push rax 4771496ba7bSLoGin 4781496ba7bSLoGin mov [rdi + {off_rbp}], rbp 4791496ba7bSLoGin mov rbp, [rsi + {off_rbp}] 4801496ba7bSLoGin 4811496ba7bSLoGin mov [rdi + {off_rsp}], rsp 4821496ba7bSLoGin mov rsp, [rsi + {off_rsp}] 4831496ba7bSLoGin 4841496ba7bSLoGin // // push RFLAGS (can only be modified via stack) 4851496ba7bSLoGin pushfq 4861496ba7bSLoGin // // pop RFLAGS into `self.rflags` 4871496ba7bSLoGin pop QWORD PTR [rdi + {off_rflags}] 4881496ba7bSLoGin 4891496ba7bSLoGin // // push `next.rflags` 4901496ba7bSLoGin push QWORD PTR [rsi + {off_rflags}] 4911496ba7bSLoGin // // pop into RFLAGS 4921496ba7bSLoGin popfq 4931496ba7bSLoGin 4941496ba7bSLoGin // push next rip to stack 4951496ba7bSLoGin push QWORD PTR [rsi + {off_rip}] 4961496ba7bSLoGin 4971496ba7bSLoGin 4981496ba7bSLoGin // When we return, we cannot even guarantee that the return address on the stack, points to 4991496ba7bSLoGin // the calling function. Thus, we have to execute this Rust hook by 5001496ba7bSLoGin // ourselves, which will unlock the contexts before the later switch. 5011496ba7bSLoGin 5021496ba7bSLoGin // Note that switch_finish_hook will be responsible for executing `ret`. 5031496ba7bSLoGin jmp {switch_hook} 5041496ba7bSLoGin "), 5051496ba7bSLoGin 5061496ba7bSLoGin off_rflags = const(offset_of!(ArchPCBInfo, rflags)), 5071496ba7bSLoGin 5081496ba7bSLoGin off_rbx = const(offset_of!(ArchPCBInfo, rbx)), 5091496ba7bSLoGin off_r12 = const(offset_of!(ArchPCBInfo, r12)), 5101496ba7bSLoGin off_r13 = const(offset_of!(ArchPCBInfo, r13)), 5111496ba7bSLoGin off_r14 = const(offset_of!(ArchPCBInfo, r14)), 5121496ba7bSLoGin off_rbp = const(offset_of!(ArchPCBInfo, rbp)), 5131496ba7bSLoGin off_rsp = const(offset_of!(ArchPCBInfo, rsp)), 5141496ba7bSLoGin off_r15 = const(offset_of!(ArchPCBInfo, r15)), 5151496ba7bSLoGin off_rip = const(offset_of!(ArchPCBInfo, rip)), 5161496ba7bSLoGin off_fs = const(offset_of!(ArchPCBInfo, fs)), 5171496ba7bSLoGin off_gs = const(offset_of!(ArchPCBInfo, gs)), 5181496ba7bSLoGin 5191496ba7bSLoGin switch_hook = sym crate::process::switch_finish_hook, 5201496ba7bSLoGin options(noreturn), 5211496ba7bSLoGin ); 5221496ba7bSLoGin } 5231496ba7bSLoGin 5241496ba7bSLoGin /// 从`switch_to_inner`返回后,执行这个函数 5251496ba7bSLoGin /// 5261496ba7bSLoGin /// 也就是说,当进程再次被调度时,会从这里开始执行 5271496ba7bSLoGin #[inline(never)] 5281496ba7bSLoGin unsafe extern "sysv64" fn switch_back() { 5291496ba7bSLoGin asm!(concat!( 5301496ba7bSLoGin " 5311496ba7bSLoGin pop rax 5321496ba7bSLoGin pop rbp 5331496ba7bSLoGin " 5341496ba7bSLoGin )) 5351496ba7bSLoGin } 5361496ba7bSLoGin 5371496ba7bSLoGin pub unsafe fn arch_switch_to_user(path: String, argv: Vec<String>, envp: Vec<String>) -> ! { 5381496ba7bSLoGin // 以下代码不能发生中断 5391496ba7bSLoGin CurrentIrqArch::interrupt_disable(); 5401496ba7bSLoGin 5411496ba7bSLoGin let current_pcb = ProcessManager::current_pcb(); 5421496ba7bSLoGin let trap_frame_vaddr = VirtAddr::new( 5431496ba7bSLoGin current_pcb.kernel_stack().stack_max_address().data() - core::mem::size_of::<TrapFrame>(), 5441496ba7bSLoGin ); 5451496ba7bSLoGin // kdebug!("trap_frame_vaddr: {:?}", trap_frame_vaddr); 5461496ba7bSLoGin let new_rip = VirtAddr::new(ret_from_intr as usize); 5471496ba7bSLoGin 5481496ba7bSLoGin assert!( 5491496ba7bSLoGin (x86::current::registers::rsp() as usize) < trap_frame_vaddr.data(), 5501496ba7bSLoGin "arch_switch_to_user(): current_rsp >= fake trap 5511496ba7bSLoGin frame vaddr, this may cause some illegal access to memory! 5521496ba7bSLoGin rsp: {:#x}, trap_frame_vaddr: {:#x}", 5531496ba7bSLoGin x86::current::registers::rsp() as usize, 5541496ba7bSLoGin trap_frame_vaddr.data() 5551496ba7bSLoGin ); 5561496ba7bSLoGin 5571496ba7bSLoGin let mut arch_guard = current_pcb.arch_info_irqsave(); 5581496ba7bSLoGin arch_guard.rsp = trap_frame_vaddr.data(); 5591496ba7bSLoGin 56016033951SGnoCiYeH arch_guard.fs = USER_DS; 56116033951SGnoCiYeH arch_guard.gs = USER_DS; 56216033951SGnoCiYeH 56316033951SGnoCiYeH // 将内核gs数据压进cpu 56416033951SGnoCiYeH arch_guard.store_kernel_gsbase(); 5651496ba7bSLoGin 5661496ba7bSLoGin switch_fs_and_gs( 56716033951SGnoCiYeH SegmentSelector::from_bits_truncate(arch_guard.fs.bits()), 56816033951SGnoCiYeH SegmentSelector::from_bits_truncate(arch_guard.gs.bits()), 5691496ba7bSLoGin ); 5701496ba7bSLoGin arch_guard.rip = new_rip.data(); 5711496ba7bSLoGin 5721496ba7bSLoGin drop(arch_guard); 5731496ba7bSLoGin 5741496ba7bSLoGin // 删除kthread的标志 5751496ba7bSLoGin current_pcb.flags().remove(ProcessFlags::KTHREAD); 5761496ba7bSLoGin current_pcb.worker_private().take(); 5771496ba7bSLoGin 5781496ba7bSLoGin let mut trap_frame = TrapFrame::new(); 5791496ba7bSLoGin 5801496ba7bSLoGin compiler_fence(Ordering::SeqCst); 5811496ba7bSLoGin Syscall::do_execve(path, argv, envp, &mut trap_frame).unwrap_or_else(|e| { 5821496ba7bSLoGin panic!( 5831496ba7bSLoGin "arch_switch_to_user(): pid: {pid:?}, Failed to execve: , error: {e:?}", 5841496ba7bSLoGin pid = current_pcb.pid(), 5851496ba7bSLoGin e = e 5861496ba7bSLoGin ); 5871496ba7bSLoGin }); 5881496ba7bSLoGin compiler_fence(Ordering::SeqCst); 5891496ba7bSLoGin 5901496ba7bSLoGin // 重要!在这里之后,一定要保证上面的引用计数变量、动态申请的变量、锁的守卫都被drop了,否则可能导致内存安全问题! 5911496ba7bSLoGin 5921496ba7bSLoGin drop(current_pcb); 5931496ba7bSLoGin 5941496ba7bSLoGin compiler_fence(Ordering::SeqCst); 5951496ba7bSLoGin ready_to_switch_to_user(trap_frame, trap_frame_vaddr.data(), new_rip.data()); 5961496ba7bSLoGin } 5971496ba7bSLoGin 5981496ba7bSLoGin /// 由于需要依赖ret来切换到用户态,所以不能inline 5991496ba7bSLoGin #[inline(never)] 6001496ba7bSLoGin unsafe extern "sysv64" fn ready_to_switch_to_user( 6011496ba7bSLoGin trap_frame: TrapFrame, 6021496ba7bSLoGin trapframe_vaddr: usize, 6031496ba7bSLoGin new_rip: usize, 6041496ba7bSLoGin ) -> ! { 6051496ba7bSLoGin *(trapframe_vaddr as *mut TrapFrame) = trap_frame; 6061496ba7bSLoGin asm!( 60716033951SGnoCiYeH "swapgs", 6081496ba7bSLoGin "mov rsp, {trapframe_vaddr}", 6091496ba7bSLoGin "push {new_rip}", 6101496ba7bSLoGin "ret", 6111496ba7bSLoGin trapframe_vaddr = in(reg) trapframe_vaddr, 6121496ba7bSLoGin new_rip = in(reg) new_rip 6131496ba7bSLoGin ); 6141496ba7bSLoGin unreachable!() 6151496ba7bSLoGin } 616