49 lines
1.2 KiB
Rust
49 lines
1.2 KiB
Rust
//! Implementation of [`TrapContext`]
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use riscv::register::sstatus::{self, Sstatus, SPP};
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#[repr(C)]
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#[derive(Debug)]
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///trap context structure containing sstatus, sepc and registers
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pub struct TrapContext {
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/// general regs[0..31]
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pub x: [usize; 32],
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/// CSR sstatus
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pub sstatus: Sstatus,
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/// CSR sepc
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pub sepc: usize,
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/// Addr of Page Table
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pub kernel_satp: usize,
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/// kernel stack
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pub kernel_sp: usize,
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/// Addr of trap_handler function
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pub trap_handler: usize,
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}
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impl TrapContext {
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///set stack pointer to x_2 reg (sp)
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pub fn set_sp(&mut self, sp: usize) {
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self.x[2] = sp;
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}
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///init app context
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pub fn app_init_context(
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entry: usize,
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sp: usize,
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kernel_satp: usize,
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kernel_sp: usize,
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trap_handler: usize,
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) -> Self {
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let mut sstatus = sstatus::read();
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// set CPU privilege to User after trapping back
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sstatus.set_spp(SPP::User);
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let mut cx = Self {
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x: [0; 32],
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sstatus,
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sepc: entry,
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kernel_satp,
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kernel_sp,
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trap_handler,
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};
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cx.set_sp(sp);
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cx
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}
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}
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