11496ba7bSLoGin use core::{
21496ba7bSLoGin arch::asm,
31496ba7bSLoGin intrinsics::unlikely,
41496ba7bSLoGin mem::ManuallyDrop,
51496ba7bSLoGin sync::atomic::{compiler_fence, Ordering},
61496ba7bSLoGin };
71496ba7bSLoGin
8f75cb0f8SLoGin use alloc::sync::{Arc, Weak};
91496ba7bSLoGin
107b32f508SLoGin use kdepends::memoffset::offset_of;
11*2eab6dd7S曾俊 use log::{error, warn};
1291e9d4abSLoGin use system_error::SystemError;
131496ba7bSLoGin use x86::{controlregs::Cr4, segmentation::SegmentSelector};
141496ba7bSLoGin
151496ba7bSLoGin use crate::{
161496ba7bSLoGin arch::process::table::TSSManager,
171496ba7bSLoGin exception::InterruptArch,
181496ba7bSLoGin libs::spinlock::SpinLockGuard,
1940169973SLoGin mm::VirtAddr,
201496ba7bSLoGin process::{
21971462beSGnoCiYeH fork::{CloneFlags, KernelCloneArgs},
2240169973SLoGin KernelStack, ProcessControlBlock, ProcessFlags, ProcessManager, PROCESS_SWITCH_RESULT,
231496ba7bSLoGin },
2491e9d4abSLoGin syscall::Syscall,
251496ba7bSLoGin };
261496ba7bSLoGin
271496ba7bSLoGin use self::{
281496ba7bSLoGin kthread::kernel_thread_bootstrap_stage1,
29971462beSGnoCiYeH syscall::ARCH_SET_FS,
301496ba7bSLoGin table::{switch_fs_and_gs, KERNEL_DS, USER_DS},
311496ba7bSLoGin };
321496ba7bSLoGin
3316033951SGnoCiYeH use super::{fpu::FpState, interrupt::TrapFrame, syscall::X86_64GSData, CurrentIrqArch};
341496ba7bSLoGin
355b59005fSLoGin pub mod idle;
361496ba7bSLoGin pub mod kthread;
371496ba7bSLoGin pub mod syscall;
381496ba7bSLoGin pub mod table;
391496ba7bSLoGin
401496ba7bSLoGin extern "C" {
411496ba7bSLoGin /// 从中断返回
ret_from_intr()421496ba7bSLoGin fn ret_from_intr();
431496ba7bSLoGin }
441496ba7bSLoGin
45de71ec25SLoGin #[allow(dead_code)]
46de71ec25SLoGin #[repr(align(32768))]
47de71ec25SLoGin union InitProcUnion {
48de71ec25SLoGin /// 用于存放idle进程的内核栈
49de71ec25SLoGin idle_stack: [u8; 32768],
50de71ec25SLoGin }
51de71ec25SLoGin
52de71ec25SLoGin #[link_section = ".data.init_proc_union"]
53de71ec25SLoGin #[no_mangle]
54de71ec25SLoGin static BSP_IDLE_STACK_SPACE: InitProcUnion = InitProcUnion {
55de71ec25SLoGin idle_stack: [0; 32768],
56de71ec25SLoGin };
57de71ec25SLoGin
581496ba7bSLoGin /// PCB中与架构相关的信息
5916033951SGnoCiYeH #[derive(Debug)]
601496ba7bSLoGin #[allow(dead_code)]
611496ba7bSLoGin pub struct ArchPCBInfo {
621496ba7bSLoGin rflags: usize,
631496ba7bSLoGin rbx: usize,
641496ba7bSLoGin r12: usize,
651496ba7bSLoGin r13: usize,
661496ba7bSLoGin r14: usize,
671496ba7bSLoGin r15: usize,
681496ba7bSLoGin rbp: usize,
691496ba7bSLoGin rsp: usize,
701496ba7bSLoGin rip: usize,
711496ba7bSLoGin cr2: usize,
721496ba7bSLoGin fsbase: usize,
731496ba7bSLoGin gsbase: usize,
7416033951SGnoCiYeH fs: SegmentSelector,
7516033951SGnoCiYeH gs: SegmentSelector,
7616033951SGnoCiYeH /// 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
7716033951SGnoCiYeH gsdata: X86_64GSData,
781496ba7bSLoGin /// 浮点寄存器的状态
791496ba7bSLoGin fp_state: Option<FpState>,
801496ba7bSLoGin }
811496ba7bSLoGin
821496ba7bSLoGin #[allow(dead_code)]
831496ba7bSLoGin impl ArchPCBInfo {
841496ba7bSLoGin /// 创建一个新的ArchPCBInfo
851496ba7bSLoGin ///
861496ba7bSLoGin /// ## 参数
871496ba7bSLoGin ///
881496ba7bSLoGin /// - `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。
891496ba7bSLoGin ///
901496ba7bSLoGin /// ## 返回值
911496ba7bSLoGin ///
921496ba7bSLoGin /// 返回一个新的ArchPCBInfo
930d6cf65aSLoGin #[inline(never)]
new(kstack: &KernelStack) -> Self9416033951SGnoCiYeH pub fn new(kstack: &KernelStack) -> Self {
951496ba7bSLoGin let mut r = Self {
961496ba7bSLoGin rflags: 0,
971496ba7bSLoGin rbx: 0,
981496ba7bSLoGin r12: 0,
991496ba7bSLoGin r13: 0,
1001496ba7bSLoGin r14: 0,
1011496ba7bSLoGin r15: 0,
1021496ba7bSLoGin rbp: 0,
1031496ba7bSLoGin rsp: 0,
1041496ba7bSLoGin rip: 0,
1051496ba7bSLoGin cr2: 0,
1061496ba7bSLoGin fsbase: 0,
1071496ba7bSLoGin gsbase: 0,
10816033951SGnoCiYeH gsdata: X86_64GSData {
10916033951SGnoCiYeH kaddr: VirtAddr::new(0),
11016033951SGnoCiYeH uaddr: VirtAddr::new(0),
11116033951SGnoCiYeH },
11216033951SGnoCiYeH fs: KERNEL_DS,
11316033951SGnoCiYeH gs: KERNEL_DS,
1141496ba7bSLoGin fp_state: None,
1151496ba7bSLoGin };
1161496ba7bSLoGin
11716033951SGnoCiYeH r.rsp = kstack.stack_max_address().data() - 8;
1181496ba7bSLoGin r.rbp = kstack.stack_max_address().data();
1191496ba7bSLoGin
1201496ba7bSLoGin return r;
1211496ba7bSLoGin }
1221496ba7bSLoGin
set_stack(&mut self, stack: VirtAddr)1231496ba7bSLoGin pub fn set_stack(&mut self, stack: VirtAddr) {
1241496ba7bSLoGin self.rsp = stack.data();
1251496ba7bSLoGin }
1261496ba7bSLoGin
set_stack_base(&mut self, stack_base: VirtAddr)1271496ba7bSLoGin pub fn set_stack_base(&mut self, stack_base: VirtAddr) {
1281496ba7bSLoGin self.rbp = stack_base.data();
1291496ba7bSLoGin }
1301496ba7bSLoGin
rbp(&self) -> usize1311496ba7bSLoGin pub fn rbp(&self) -> usize {
1321496ba7bSLoGin self.rbp
1331496ba7bSLoGin }
1341496ba7bSLoGin
push_to_stack(&mut self, value: usize)1351496ba7bSLoGin pub unsafe fn push_to_stack(&mut self, value: usize) {
1361496ba7bSLoGin self.rsp -= core::mem::size_of::<usize>();
1371496ba7bSLoGin *(self.rsp as *mut usize) = value;
1381496ba7bSLoGin }
1391496ba7bSLoGin
pop_from_stack(&mut self) -> usize1401496ba7bSLoGin pub unsafe fn pop_from_stack(&mut self) -> usize {
1411496ba7bSLoGin let value = *(self.rsp as *const usize);
1421496ba7bSLoGin self.rsp += core::mem::size_of::<usize>();
1431496ba7bSLoGin value
1441496ba7bSLoGin }
1451496ba7bSLoGin
save_fp_state(&mut self)1461496ba7bSLoGin pub fn save_fp_state(&mut self) {
1471496ba7bSLoGin if self.fp_state.is_none() {
1481496ba7bSLoGin self.fp_state = Some(FpState::new());
1491496ba7bSLoGin }
1501496ba7bSLoGin
1511496ba7bSLoGin self.fp_state.as_mut().unwrap().save();
1521496ba7bSLoGin }
1531496ba7bSLoGin
restore_fp_state(&mut self)1541496ba7bSLoGin pub fn restore_fp_state(&mut self) {
1551496ba7bSLoGin if unlikely(self.fp_state.is_none()) {
1561496ba7bSLoGin return;
1571496ba7bSLoGin }
1581496ba7bSLoGin
1591496ba7bSLoGin self.fp_state.as_mut().unwrap().restore();
1601496ba7bSLoGin }
1611496ba7bSLoGin
1623c82aa56SChiichen /// 返回浮点寄存器结构体的副本
fp_state(&self) -> &Option<FpState>1633c82aa56SChiichen pub fn fp_state(&self) -> &Option<FpState> {
1643c82aa56SChiichen &self.fp_state
1653c82aa56SChiichen }
1663c82aa56SChiichen
1673c82aa56SChiichen // 清空浮点寄存器
clear_fp_state(&mut self)1683c82aa56SChiichen pub fn clear_fp_state(&mut self) {
1693c82aa56SChiichen if unlikely(self.fp_state.is_none()) {
170*2eab6dd7S曾俊 warn!("fp_state is none");
1713c82aa56SChiichen return;
1723c82aa56SChiichen }
1733c82aa56SChiichen
1743c82aa56SChiichen self.fp_state.as_mut().unwrap().clear();
1753c82aa56SChiichen }
save_fsbase(&mut self)1761496ba7bSLoGin pub unsafe fn save_fsbase(&mut self) {
1771496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) {
1781496ba7bSLoGin self.fsbase = x86::current::segmentation::rdfsbase() as usize;
1791496ba7bSLoGin } else {
18016033951SGnoCiYeH self.fsbase = x86::msr::rdmsr(x86::msr::IA32_FS_BASE) as usize;
1811496ba7bSLoGin }
1821496ba7bSLoGin }
1831496ba7bSLoGin
save_gsbase(&mut self)1841496ba7bSLoGin pub unsafe fn save_gsbase(&mut self) {
1851496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) {
1861496ba7bSLoGin self.gsbase = x86::current::segmentation::rdgsbase() as usize;
1871496ba7bSLoGin } else {
18816033951SGnoCiYeH self.gsbase = x86::msr::rdmsr(x86::msr::IA32_GS_BASE) as usize;
1891496ba7bSLoGin }
1901496ba7bSLoGin }
1911496ba7bSLoGin
restore_fsbase(&mut self)1921496ba7bSLoGin pub unsafe fn restore_fsbase(&mut self) {
1931496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) {
1941496ba7bSLoGin x86::current::segmentation::wrfsbase(self.fsbase as u64);
195971462beSGnoCiYeH } else {
19616033951SGnoCiYeH x86::msr::wrmsr(x86::msr::IA32_FS_BASE, self.fsbase as u64);
1971496ba7bSLoGin }
1981496ba7bSLoGin }
1991496ba7bSLoGin
restore_gsbase(&mut self)2001496ba7bSLoGin pub unsafe fn restore_gsbase(&mut self) {
2011496ba7bSLoGin if x86::controlregs::cr4().contains(Cr4::CR4_ENABLE_FSGSBASE) {
2021496ba7bSLoGin x86::current::segmentation::wrgsbase(self.gsbase as u64);
203971462beSGnoCiYeH } else {
20416033951SGnoCiYeH x86::msr::wrmsr(x86::msr::IA32_GS_BASE, self.gsbase as u64);
2051496ba7bSLoGin }
2061496ba7bSLoGin }
2071496ba7bSLoGin
20816033951SGnoCiYeH /// 将gsdata写入KernelGsbase寄存器
store_kernel_gsbase(&self)20916033951SGnoCiYeH pub unsafe fn store_kernel_gsbase(&self) {
21016033951SGnoCiYeH x86::msr::wrmsr(
21116033951SGnoCiYeH x86::msr::IA32_KERNEL_GSBASE,
21216033951SGnoCiYeH &self.gsdata as *const X86_64GSData as u64,
21316033951SGnoCiYeH );
21416033951SGnoCiYeH }
21516033951SGnoCiYeH
21616033951SGnoCiYeH /// ### 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)
init_syscall_stack(&mut self, stack: &KernelStack)21716033951SGnoCiYeH pub fn init_syscall_stack(&mut self, stack: &KernelStack) {
21816033951SGnoCiYeH self.gsdata.set_kstack(stack.stack_max_address() - 8);
21916033951SGnoCiYeH }
22016033951SGnoCiYeH
fsbase(&self) -> usize2211496ba7bSLoGin pub fn fsbase(&self) -> usize {
2221496ba7bSLoGin self.fsbase
2231496ba7bSLoGin }
2241496ba7bSLoGin
gsbase(&self) -> usize2251496ba7bSLoGin pub fn gsbase(&self) -> usize {
2261496ba7bSLoGin self.gsbase
2271496ba7bSLoGin }
2283c82aa56SChiichen
cr2_mut(&mut self) -> &mut usize2293c82aa56SChiichen pub fn cr2_mut(&mut self) -> &mut usize {
2303c82aa56SChiichen &mut self.cr2
2313c82aa56SChiichen }
2323c82aa56SChiichen
fp_state_mut(&mut self) -> &mut Option<FpState>2333c82aa56SChiichen pub fn fp_state_mut(&mut self) -> &mut Option<FpState> {
2343c82aa56SChiichen &mut self.fp_state
2353c82aa56SChiichen }
23616033951SGnoCiYeH
23716033951SGnoCiYeH /// ### 克隆ArchPCBInfo,需要注意gsdata也是对应clone的
clone_all(&self) -> Self23816033951SGnoCiYeH pub fn clone_all(&self) -> Self {
23916033951SGnoCiYeH Self {
24016033951SGnoCiYeH rflags: self.rflags,
24116033951SGnoCiYeH rbx: self.rbx,
24216033951SGnoCiYeH r12: self.r12,
24316033951SGnoCiYeH r13: self.r13,
24416033951SGnoCiYeH r14: self.r14,
24516033951SGnoCiYeH r15: self.r15,
24616033951SGnoCiYeH rbp: self.rbp,
24716033951SGnoCiYeH rsp: self.rsp,
24816033951SGnoCiYeH rip: self.rip,
24916033951SGnoCiYeH cr2: self.cr2,
25016033951SGnoCiYeH fsbase: self.fsbase,
25116033951SGnoCiYeH gsbase: self.gsbase,
252b5b571e0SLoGin fs: self.fs,
253b5b571e0SLoGin gs: self.gs,
25416033951SGnoCiYeH gsdata: self.gsdata.clone(),
25516033951SGnoCiYeH fp_state: self.fp_state,
25616033951SGnoCiYeH }
25716033951SGnoCiYeH }
25816033951SGnoCiYeH
25916033951SGnoCiYeH // ### 从另一个ArchPCBInfo处clone,gsdata会被保留
clone_from(&mut self, from: &Self)26016033951SGnoCiYeH pub fn clone_from(&mut self, from: &Self) {
26116033951SGnoCiYeH let gsdata = self.gsdata.clone();
26216033951SGnoCiYeH *self = from.clone_all();
26316033951SGnoCiYeH self.gsdata = gsdata;
26416033951SGnoCiYeH }
2651496ba7bSLoGin }
2661496ba7bSLoGin
2671496ba7bSLoGin impl ProcessControlBlock {
2681496ba7bSLoGin /// 获取当前进程的pcb
arch_current_pcb() -> Arc<Self>2691496ba7bSLoGin pub fn arch_current_pcb() -> Arc<Self> {
2701496ba7bSLoGin // 获取栈指针
2711496ba7bSLoGin let ptr = VirtAddr::new(x86::current::registers::rsp() as usize);
2724fda81ceSLoGin
2731496ba7bSLoGin let stack_base = VirtAddr::new(ptr.data() & (!(KernelStack::ALIGN - 1)));
2744fda81ceSLoGin
2751496ba7bSLoGin // 从内核栈的最低地址处取出pcb的地址
2761496ba7bSLoGin let p = stack_base.data() as *const *const ProcessControlBlock;
2771496ba7bSLoGin if unlikely((unsafe { *p }).is_null()) {
278*2eab6dd7S曾俊 error!("p={:p}", p);
2791496ba7bSLoGin panic!("current_pcb is null");
2801496ba7bSLoGin }
2811496ba7bSLoGin unsafe {
282971462beSGnoCiYeH // 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
283971462beSGnoCiYeH let weak_wrapper: ManuallyDrop<Weak<ProcessControlBlock>> =
284971462beSGnoCiYeH ManuallyDrop::new(Weak::from_raw(*p));
2851496ba7bSLoGin
286971462beSGnoCiYeH let new_arc: Arc<ProcessControlBlock> = weak_wrapper.upgrade().unwrap();
2871496ba7bSLoGin return new_arc;
2881496ba7bSLoGin }
2891496ba7bSLoGin }
2901496ba7bSLoGin }
2911496ba7bSLoGin
2921496ba7bSLoGin impl ProcessManager {
arch_init()2931496ba7bSLoGin pub fn arch_init() {
29440169973SLoGin // do nothing
2951496ba7bSLoGin }
2961496ba7bSLoGin /// fork的过程中复制线程
2971496ba7bSLoGin ///
2981496ba7bSLoGin /// 由于这个过程与具体的架构相关,所以放在这里
copy_thread( current_pcb: &Arc<ProcessControlBlock>, new_pcb: &Arc<ProcessControlBlock>, clone_args: KernelCloneArgs, current_trapframe: &TrapFrame, ) -> Result<(), SystemError>2991496ba7bSLoGin pub fn copy_thread(
3001496ba7bSLoGin current_pcb: &Arc<ProcessControlBlock>,
3011496ba7bSLoGin new_pcb: &Arc<ProcessControlBlock>,
302971462beSGnoCiYeH clone_args: KernelCloneArgs,
3031496ba7bSLoGin current_trapframe: &TrapFrame,
3041496ba7bSLoGin ) -> Result<(), SystemError> {
305971462beSGnoCiYeH let clone_flags = clone_args.flags;
306b5b571e0SLoGin let mut child_trapframe = *current_trapframe;
3071496ba7bSLoGin
3081496ba7bSLoGin // 子进程的返回值为0
3091496ba7bSLoGin child_trapframe.set_return_value(0);
3101496ba7bSLoGin
3111496ba7bSLoGin // 设置子进程的栈基址(开始执行中断返回流程时的栈基址)
3120d6cf65aSLoGin let mut new_arch_guard = unsafe { new_pcb.arch_info() };
3131496ba7bSLoGin let kernel_stack_guard = new_pcb.kernel_stack();
3141496ba7bSLoGin
3151496ba7bSLoGin // 设置子进程在内核态开始执行时的rsp、rbp
3161496ba7bSLoGin new_arch_guard.set_stack_base(kernel_stack_guard.stack_max_address());
3171496ba7bSLoGin
3181496ba7bSLoGin let trap_frame_vaddr: VirtAddr =
3191496ba7bSLoGin kernel_stack_guard.stack_max_address() - core::mem::size_of::<TrapFrame>();
3201496ba7bSLoGin new_arch_guard.set_stack(trap_frame_vaddr);
3211496ba7bSLoGin
3221496ba7bSLoGin // 拷贝栈帧
3231496ba7bSLoGin unsafe {
324971462beSGnoCiYeH let usp = clone_args.stack;
325971462beSGnoCiYeH if usp != 0 {
326971462beSGnoCiYeH child_trapframe.rsp = usp as u64;
327971462beSGnoCiYeH }
3281496ba7bSLoGin let trap_frame_ptr = trap_frame_vaddr.data() as *mut TrapFrame;
3291496ba7bSLoGin *trap_frame_ptr = child_trapframe;
3301496ba7bSLoGin }
3311496ba7bSLoGin
3321496ba7bSLoGin let current_arch_guard = current_pcb.arch_info_irqsave();
3331496ba7bSLoGin new_arch_guard.fsbase = current_arch_guard.fsbase;
3341496ba7bSLoGin new_arch_guard.gsbase = current_arch_guard.gsbase;
3351496ba7bSLoGin new_arch_guard.fs = current_arch_guard.fs;
3361496ba7bSLoGin new_arch_guard.gs = current_arch_guard.gs;
337b5b571e0SLoGin new_arch_guard.fp_state = current_arch_guard.fp_state;
3381496ba7bSLoGin
3391496ba7bSLoGin // 拷贝浮点寄存器的状态
3401496ba7bSLoGin if let Some(fp_state) = current_arch_guard.fp_state.as_ref() {
3411496ba7bSLoGin new_arch_guard.fp_state = Some(*fp_state);
3421496ba7bSLoGin }
3431496ba7bSLoGin drop(current_arch_guard);
3441496ba7bSLoGin
3451496ba7bSLoGin // 设置返回地址(子进程开始执行的指令地址)
3461496ba7bSLoGin if new_pcb.flags().contains(ProcessFlags::KTHREAD) {
3471496ba7bSLoGin let kthread_bootstrap_stage1_func_addr = kernel_thread_bootstrap_stage1 as usize;
3481496ba7bSLoGin new_arch_guard.rip = kthread_bootstrap_stage1_func_addr;
3491496ba7bSLoGin } else {
3501496ba7bSLoGin new_arch_guard.rip = ret_from_intr as usize;
3511496ba7bSLoGin }
3521496ba7bSLoGin
353971462beSGnoCiYeH // 设置tls
354971462beSGnoCiYeH if clone_flags.contains(CloneFlags::CLONE_SETTLS) {
355971462beSGnoCiYeH drop(new_arch_guard);
356971462beSGnoCiYeH Syscall::do_arch_prctl_64(new_pcb, ARCH_SET_FS, clone_args.tls, true)?;
357971462beSGnoCiYeH }
358971462beSGnoCiYeH
3591496ba7bSLoGin return Ok(());
3601496ba7bSLoGin }
3611496ba7bSLoGin
3621496ba7bSLoGin /// 切换进程
3631496ba7bSLoGin ///
3641496ba7bSLoGin /// ## 参数
3651496ba7bSLoGin ///
3661496ba7bSLoGin /// - `prev`:上一个进程的pcb
3671496ba7bSLoGin /// - `next`:下一个进程的pcb
switch_process(prev: Arc<ProcessControlBlock>, next: Arc<ProcessControlBlock>)3681496ba7bSLoGin pub unsafe fn switch_process(prev: Arc<ProcessControlBlock>, next: Arc<ProcessControlBlock>) {
369b5b571e0SLoGin assert!(!CurrentIrqArch::is_irq_enabled());
3701496ba7bSLoGin
3711496ba7bSLoGin // 保存浮点寄存器
3720d6cf65aSLoGin prev.arch_info_irqsave().save_fp_state();
3731496ba7bSLoGin // 切换浮点寄存器
3740d6cf65aSLoGin next.arch_info_irqsave().restore_fp_state();
3751496ba7bSLoGin
3761496ba7bSLoGin // 切换fsbase
3770d6cf65aSLoGin prev.arch_info_irqsave().save_fsbase();
3780d6cf65aSLoGin next.arch_info_irqsave().restore_fsbase();
3791496ba7bSLoGin
3801496ba7bSLoGin // 切换gsbase
38116033951SGnoCiYeH Self::switch_gsbase(&prev, &next);
3821496ba7bSLoGin
3831496ba7bSLoGin // 切换地址空间
3841496ba7bSLoGin let next_addr_space = next.basic().user_vm().as_ref().unwrap().clone();
3851496ba7bSLoGin compiler_fence(Ordering::SeqCst);
3861496ba7bSLoGin
3871496ba7bSLoGin next_addr_space.read().user_mapper.utable.make_current();
388971462beSGnoCiYeH drop(next_addr_space);
3891496ba7bSLoGin compiler_fence(Ordering::SeqCst);
3901496ba7bSLoGin // 切换内核栈
3911496ba7bSLoGin
3921496ba7bSLoGin // 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)
3930d6cf65aSLoGin let next_arch = SpinLockGuard::leak(next.arch_info_irqsave()) as *mut ArchPCBInfo;
3940d6cf65aSLoGin let prev_arch = SpinLockGuard::leak(prev.arch_info_irqsave()) as *mut ArchPCBInfo;
3951496ba7bSLoGin
396971462beSGnoCiYeH (*prev_arch).rip = switch_back as usize;
3971496ba7bSLoGin
3981496ba7bSLoGin // 恢复当前的 preempt count*2
3991496ba7bSLoGin ProcessManager::current_pcb().preempt_enable();
4001496ba7bSLoGin ProcessManager::current_pcb().preempt_enable();
4011496ba7bSLoGin
4021496ba7bSLoGin // 切换tss
4031496ba7bSLoGin TSSManager::current_tss().set_rsp(
4041496ba7bSLoGin x86::Ring::Ring0,
4051496ba7bSLoGin next.kernel_stack().stack_max_address().data() as u64,
4061496ba7bSLoGin );
40740169973SLoGin PROCESS_SWITCH_RESULT.as_mut().unwrap().get_mut().prev_pcb = Some(prev);
40840169973SLoGin PROCESS_SWITCH_RESULT.as_mut().unwrap().get_mut().next_pcb = Some(next);
409*2eab6dd7S曾俊 // debug!("switch tss ok");
410de71ec25SLoGin compiler_fence(Ordering::SeqCst);
4111496ba7bSLoGin // 正式切换上下文
4121496ba7bSLoGin switch_to_inner(prev_arch, next_arch);
4131496ba7bSLoGin }
41416033951SGnoCiYeH
switch_gsbase(prev: &Arc<ProcessControlBlock>, next: &Arc<ProcessControlBlock>)41516033951SGnoCiYeH unsafe fn switch_gsbase(prev: &Arc<ProcessControlBlock>, next: &Arc<ProcessControlBlock>) {
41616033951SGnoCiYeH asm!("swapgs", options(nostack, preserves_flags));
4170d6cf65aSLoGin prev.arch_info_irqsave().save_gsbase();
4180d6cf65aSLoGin next.arch_info_irqsave().restore_gsbase();
41916033951SGnoCiYeH // 将下一个进程的kstack写入kernel_gsbase
4200d6cf65aSLoGin next.arch_info_irqsave().store_kernel_gsbase();
42116033951SGnoCiYeH asm!("swapgs", options(nostack, preserves_flags));
42216033951SGnoCiYeH }
4231496ba7bSLoGin }
4241496ba7bSLoGin
4251496ba7bSLoGin /// 保存上下文,然后切换进程,接着jmp到`switch_finish_hook`钩子函数
4261496ba7bSLoGin #[naked]
switch_to_inner(prev: *mut ArchPCBInfo, next: *mut ArchPCBInfo)427971462beSGnoCiYeH unsafe extern "sysv64" fn switch_to_inner(prev: *mut ArchPCBInfo, next: *mut ArchPCBInfo) {
4281496ba7bSLoGin asm!(
4291496ba7bSLoGin // As a quick reminder for those who are unfamiliar with the System V ABI (extern "C"):
4301496ba7bSLoGin //
4311496ba7bSLoGin // - the current parameters are passed in the registers `rdi`, `rsi`,
4321496ba7bSLoGin // - we can modify scratch registers, e.g. rax
4331496ba7bSLoGin // - we cannot change callee-preserved registers arbitrarily, e.g. rbx, which is why we
4341496ba7bSLoGin // store them here in the first place.
4351496ba7bSLoGin concat!("
4361496ba7bSLoGin // Save old registers, and load new ones
4371496ba7bSLoGin mov [rdi + {off_rbx}], rbx
4381496ba7bSLoGin mov rbx, [rsi + {off_rbx}]
4391496ba7bSLoGin
4401496ba7bSLoGin mov [rdi + {off_r12}], r12
4411496ba7bSLoGin mov r12, [rsi + {off_r12}]
4421496ba7bSLoGin
4431496ba7bSLoGin mov [rdi + {off_r13}], r13
4441496ba7bSLoGin mov r13, [rsi + {off_r13}]
4451496ba7bSLoGin
4461496ba7bSLoGin mov [rdi + {off_r14}], r14
4471496ba7bSLoGin mov r14, [rsi + {off_r14}]
4481496ba7bSLoGin
4491496ba7bSLoGin mov [rdi + {off_r15}], r15
4501496ba7bSLoGin mov r15, [rsi + {off_r15}]
4511496ba7bSLoGin
4521496ba7bSLoGin // switch segment registers (这些寄存器只能通过接下来的switch_hook的return来切换)
4531496ba7bSLoGin mov [rdi + {off_fs}], fs
4541496ba7bSLoGin mov [rdi + {off_gs}], gs
4551496ba7bSLoGin
456971462beSGnoCiYeH // mov fs, [rsi + {off_fs}]
457971462beSGnoCiYeH // mov gs, [rsi + {off_gs}]
458971462beSGnoCiYeH
4591496ba7bSLoGin mov [rdi + {off_rbp}], rbp
4601496ba7bSLoGin mov rbp, [rsi + {off_rbp}]
4611496ba7bSLoGin
4621496ba7bSLoGin mov [rdi + {off_rsp}], rsp
4631496ba7bSLoGin mov rsp, [rsi + {off_rsp}]
4641496ba7bSLoGin
4651496ba7bSLoGin // // push RFLAGS (can only be modified via stack)
4661496ba7bSLoGin pushfq
4671496ba7bSLoGin // // pop RFLAGS into `self.rflags`
4681496ba7bSLoGin pop QWORD PTR [rdi + {off_rflags}]
4691496ba7bSLoGin
4701496ba7bSLoGin // // push `next.rflags`
4711496ba7bSLoGin push QWORD PTR [rsi + {off_rflags}]
4721496ba7bSLoGin // // pop into RFLAGS
4731496ba7bSLoGin popfq
4741496ba7bSLoGin
4751496ba7bSLoGin // push next rip to stack
4761496ba7bSLoGin push QWORD PTR [rsi + {off_rip}]
4771496ba7bSLoGin
4781496ba7bSLoGin
4791496ba7bSLoGin // When we return, we cannot even guarantee that the return address on the stack, points to
4801496ba7bSLoGin // the calling function. Thus, we have to execute this Rust hook by
4811496ba7bSLoGin // ourselves, which will unlock the contexts before the later switch.
4821496ba7bSLoGin
4831496ba7bSLoGin // Note that switch_finish_hook will be responsible for executing `ret`.
4841496ba7bSLoGin jmp {switch_hook}
4851496ba7bSLoGin "),
4861496ba7bSLoGin
4871496ba7bSLoGin off_rflags = const(offset_of!(ArchPCBInfo, rflags)),
4881496ba7bSLoGin
4891496ba7bSLoGin off_rbx = const(offset_of!(ArchPCBInfo, rbx)),
4901496ba7bSLoGin off_r12 = const(offset_of!(ArchPCBInfo, r12)),
4911496ba7bSLoGin off_r13 = const(offset_of!(ArchPCBInfo, r13)),
4921496ba7bSLoGin off_r14 = const(offset_of!(ArchPCBInfo, r14)),
4931496ba7bSLoGin off_rbp = const(offset_of!(ArchPCBInfo, rbp)),
4941496ba7bSLoGin off_rsp = const(offset_of!(ArchPCBInfo, rsp)),
4951496ba7bSLoGin off_r15 = const(offset_of!(ArchPCBInfo, r15)),
4961496ba7bSLoGin off_rip = const(offset_of!(ArchPCBInfo, rip)),
4971496ba7bSLoGin off_fs = const(offset_of!(ArchPCBInfo, fs)),
4981496ba7bSLoGin off_gs = const(offset_of!(ArchPCBInfo, gs)),
4991496ba7bSLoGin
5001496ba7bSLoGin switch_hook = sym crate::process::switch_finish_hook,
5011496ba7bSLoGin options(noreturn),
5021496ba7bSLoGin );
5031496ba7bSLoGin }
5041496ba7bSLoGin
5053959e94dS曾俊 #[naked]
switch_back() -> !5063959e94dS曾俊 unsafe extern "sysv64" fn switch_back() -> ! {
5073959e94dS曾俊 asm!("ret", options(noreturn));
5081496ba7bSLoGin }
5091496ba7bSLoGin
arch_switch_to_user(trap_frame: TrapFrame) -> !510f75cb0f8SLoGin pub unsafe fn arch_switch_to_user(trap_frame: TrapFrame) -> ! {
5111496ba7bSLoGin // 以下代码不能发生中断
5121496ba7bSLoGin CurrentIrqArch::interrupt_disable();
5131496ba7bSLoGin
5141496ba7bSLoGin let current_pcb = ProcessManager::current_pcb();
5151496ba7bSLoGin let trap_frame_vaddr = VirtAddr::new(
5161496ba7bSLoGin current_pcb.kernel_stack().stack_max_address().data() - core::mem::size_of::<TrapFrame>(),
5171496ba7bSLoGin );
518*2eab6dd7S曾俊 // debug!("trap_frame_vaddr: {:?}", trap_frame_vaddr);
5191496ba7bSLoGin
5201496ba7bSLoGin assert!(
5211496ba7bSLoGin (x86::current::registers::rsp() as usize) < trap_frame_vaddr.data(),
5221496ba7bSLoGin "arch_switch_to_user(): current_rsp >= fake trap
5231496ba7bSLoGin frame vaddr, this may cause some illegal access to memory!
5241496ba7bSLoGin rsp: {:#x}, trap_frame_vaddr: {:#x}",
5251496ba7bSLoGin x86::current::registers::rsp() as usize,
5261496ba7bSLoGin trap_frame_vaddr.data()
5271496ba7bSLoGin );
5281496ba7bSLoGin
529f75cb0f8SLoGin let new_rip = VirtAddr::new(ret_from_intr as usize);
5301496ba7bSLoGin let mut arch_guard = current_pcb.arch_info_irqsave();
5311496ba7bSLoGin arch_guard.rsp = trap_frame_vaddr.data();
5321496ba7bSLoGin
53316033951SGnoCiYeH arch_guard.fs = USER_DS;
53416033951SGnoCiYeH arch_guard.gs = USER_DS;
53516033951SGnoCiYeH
53616033951SGnoCiYeH // 将内核gs数据压进cpu
53716033951SGnoCiYeH arch_guard.store_kernel_gsbase();
5381496ba7bSLoGin
5391496ba7bSLoGin switch_fs_and_gs(
54016033951SGnoCiYeH SegmentSelector::from_bits_truncate(arch_guard.fs.bits()),
54116033951SGnoCiYeH SegmentSelector::from_bits_truncate(arch_guard.gs.bits()),
5421496ba7bSLoGin );
5431496ba7bSLoGin arch_guard.rip = new_rip.data();
5441496ba7bSLoGin
5451496ba7bSLoGin drop(arch_guard);
5461496ba7bSLoGin
547f75cb0f8SLoGin drop(current_pcb);
5481496ba7bSLoGin compiler_fence(Ordering::SeqCst);
5491496ba7bSLoGin
5501496ba7bSLoGin // 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!
5511496ba7bSLoGin
5521496ba7bSLoGin compiler_fence(Ordering::SeqCst);
5531496ba7bSLoGin ready_to_switch_to_user(trap_frame, trap_frame_vaddr.data(), new_rip.data());
5541496ba7bSLoGin }
5551496ba7bSLoGin
5561496ba7bSLoGin /// 由于需要依赖ret来切换到用户态,所以不能inline
5571496ba7bSLoGin #[inline(never)]
ready_to_switch_to_user( trap_frame: TrapFrame, trapframe_vaddr: usize, new_rip: usize, ) -> !5581496ba7bSLoGin unsafe extern "sysv64" fn ready_to_switch_to_user(
5591496ba7bSLoGin trap_frame: TrapFrame,
5601496ba7bSLoGin trapframe_vaddr: usize,
5611496ba7bSLoGin new_rip: usize,
5621496ba7bSLoGin ) -> ! {
5631496ba7bSLoGin *(trapframe_vaddr as *mut TrapFrame) = trap_frame;
564f0c87a89SGnoCiYeH compiler_fence(Ordering::SeqCst);
5651496ba7bSLoGin asm!(
56616033951SGnoCiYeH "swapgs",
5671496ba7bSLoGin "mov rsp, {trapframe_vaddr}",
5681496ba7bSLoGin "push {new_rip}",
5691496ba7bSLoGin "ret",
5701496ba7bSLoGin trapframe_vaddr = in(reg) trapframe_vaddr,
5711496ba7bSLoGin new_rip = in(reg) new_rip
5721496ba7bSLoGin );
5731496ba7bSLoGin unreachable!()
5741496ba7bSLoGin }
575f0c87a89SGnoCiYeH
576f0c87a89SGnoCiYeH // bitflags! {
577f0c87a89SGnoCiYeH // pub struct ProcessThreadFlags: u32 {
578f0c87a89SGnoCiYeH // /*
579f0c87a89SGnoCiYeH // * thread information flags
580f0c87a89SGnoCiYeH // * - these are process state flags that various assembly files
581f0c87a89SGnoCiYeH // * may need to access
582f0c87a89SGnoCiYeH // */
583f0c87a89SGnoCiYeH // const TIF_NOTIFY_RESUME = 1 << 1; /* callback before returning to user */
584f0c87a89SGnoCiYeH // const TIF_SIGPENDING = 1 << 2; /* signal pending */
585f0c87a89SGnoCiYeH // const TIF_NEED_RESCHED = 1 << 3; /* rescheduling necessary */
586f0c87a89SGnoCiYeH // const TIF_SINGLESTEP = 1 << 4; /* reenable singlestep on user return*/
587f0c87a89SGnoCiYeH // const TIF_SSBD = 1 << 5; /* Speculative store bypass disable */
588f0c87a89SGnoCiYeH // const TIF_SPEC_IB = 1 << 9; /* Indirect branch speculation mitigation */
589f0c87a89SGnoCiYeH // const TIF_SPEC_L1D_FLUSH = 1 << 10; /* Flush L1D on mm switches (processes) */
590f0c87a89SGnoCiYeH // const TIF_USER_RETURN_NOTIFY = 1 << 11; /* notify kernel of userspace return */
591f0c87a89SGnoCiYeH // const TIF_UPROBE = 1 << 12; /* breakpointed or singlestepping */
592f0c87a89SGnoCiYeH // const TIF_PATCH_PENDING = 1 << 13; /* pending live patching update */
593f0c87a89SGnoCiYeH // const TIF_NEED_FPU_LOAD = 1 << 14; /* load FPU on return to userspace */
594f0c87a89SGnoCiYeH // const TIF_NOCPUID = 1 << 15; /* CPUID is not accessible in userland */
595f0c87a89SGnoCiYeH // const TIF_NOTSC = 1 << 16; /* TSC is not accessible in userland */
596f0c87a89SGnoCiYeH // const TIF_NOTIFY_SIGNAL = 1 << 17; /* signal notifications exist */
597f0c87a89SGnoCiYeH // const TIF_MEMDIE = 1 << 20; /* is terminating due to OOM killer */
598f0c87a89SGnoCiYeH // const TIF_POLLING_NRFLAG = 1 << 21; /* idle is polling for TIF_NEED_RESCHED */
599f0c87a89SGnoCiYeH // const TIF_IO_BITMAP = 1 << 22; /* uses I/O bitmap */
600f0c87a89SGnoCiYeH // const TIF_SPEC_FORCE_UPDATE = 1 << 23; /* Force speculation MSR update in context switch */
601f0c87a89SGnoCiYeH // const TIF_FORCED_TF = 1 << 24; /* true if TF in eflags artificially */
602f0c87a89SGnoCiYeH // const TIF_BLOCKSTEP = 1 << 25; /* set when we want DEBUGCTLMSR_BTF */
603f0c87a89SGnoCiYeH // const TIF_LAZY_MMU_UPDATES = 1 << 27; /* task is updating the mmu lazily */
604f0c87a89SGnoCiYeH // const TIF_ADDR32 = 1 << 29; /* 32-bit address space on 64 bits */
605f0c87a89SGnoCiYeH // }
606f0c87a89SGnoCiYeH // }
607