1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

#[cfg(any(target_os = "linux", target_os = "macos"))]
mod fncall;
#[cfg(any(target_os = "none", target_os = "uefi"))]
mod gdt;
#[cfg(any(target_os = "none", target_os = "uefi"))]
mod idt;
#[cfg(feature = "ioport_bitmap")]
#[cfg(any(target_os = "none", target_os = "uefi"))]
pub mod ioport;
#[cfg(any(target_os = "none", target_os = "uefi"))]
mod syscall;
#[cfg(any(target_os = "none", target_os = "uefi"))]
mod trap;

#[cfg(any(target_os = "linux", target_os = "macos"))]
pub use fncall::syscall_fn_entry;
#[cfg(any(target_os = "none", target_os = "uefi"))]
pub use trap::TrapFrame;

/// Initialize interrupt handling on x86_64.
///
/// # Safety
///
/// This function will:
///
/// - Disable interrupt.
/// - Switch to a new [GDT], extend 7 more entries from the current one.
/// - Switch to a new [TSS], set `GSBASE` to its base address.
/// - Switch to a new [IDT], override the current one.
/// - Enable [`syscall`] instruction.
///     - set `EFER::SYSTEM_CALL_EXTENSIONS`
///
/// [GDT]: https://wiki.osdev.org/GDT
/// [IDT]: https://wiki.osdev.org/IDT
/// [TSS]: https://wiki.osdev.org/Task_State_Segment
/// [`syscall`]: https://www.felixcloutier.com/x86/syscall
///
#[cfg(any(target_os = "none", target_os = "uefi"))]
pub unsafe fn init() {
    use log::info;
    info!("Initializing trapframe...");

    x86_64::instructions::interrupts::disable();
    gdt::init();
    info!("GDT initialization completed");
    idt::init();
    info!("IDT initialization completed");
    syscall::init();
    info!("Syscall related register initialization completed");
}

/// User space context
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq)]
#[repr(C)]
pub struct UserContext {
    pub general: GeneralRegs,
    pub trap_num: usize,
    pub error_code: usize,
}

/// General registers
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq)]
#[repr(C)]
pub struct GeneralRegs {
    pub rax: usize,
    pub rbx: usize,
    pub rcx: usize,
    pub rdx: usize,
    pub rsi: usize,
    pub rdi: usize,
    pub rbp: usize,
    pub rsp: usize,
    pub r8: usize,
    pub r9: usize,
    pub r10: usize,
    pub r11: usize,
    pub r12: usize,
    pub r13: usize,
    pub r14: usize,
    pub r15: usize,
    pub rip: usize,
    pub rflags: usize,
    pub fsbase: usize,
    pub gsbase: usize,
}

unsafe impl pod::Pod for GeneralRegs {}
unsafe impl pod::Pod for UserContext {}

impl UserContext {
    /// Get number of syscall
    pub fn get_syscall_num(&self) -> usize {
        self.general.rax
    }

    /// Get return value of syscall
    pub fn get_syscall_ret(&self) -> usize {
        self.general.rax
    }

    /// Set return value of syscall
    pub fn set_syscall_ret(&mut self, ret: usize) {
        self.general.rax = ret;
    }

    /// Get syscall args
    pub fn get_syscall_args(&self) -> [usize; 6] {
        [
            self.general.rdi,
            self.general.rsi,
            self.general.rdx,
            self.general.r10,
            self.general.r8,
            self.general.r9,
        ]
    }

    /// Set instruction pointer
    pub fn set_ip(&mut self, ip: usize) {
        self.general.rip = ip;
    }

    /// Set stack pointer
    pub fn set_sp(&mut self, sp: usize) {
        self.general.rsp = sp;
    }

    /// Get stack pointer
    pub fn get_sp(&self) -> usize {
        self.general.rsp
    }

    /// Set tls pointer
    pub fn set_tls(&mut self, tls: usize) {
        self.general.fsbase = tls;
    }
}