use crate::arch::{ asm::csr::{CSR_SCAUSE, CSR_SEPC, CSR_SSCRATCH, CSR_SSTATUS, CSR_STVAL, SR_SPP}, cpu::LocalContext, interrupt::TrapFrame, }; use asm_macros::{restore_from_x6_to_x31, save_from_x6_to_x31}; use kdepends::memoffset::offset_of; /// Riscv64中断处理入口 #[naked] #[no_mangle] #[repr(align(4))] pub unsafe extern "C" fn handle_exception() -> ! { core::arch::naked_asm!( concat!(" /* * If coming from userspace, preserve the user thread pointer and load * the kernel thread pointer. If we came from the kernel, the scratch * register will contain 0, and we should continue on the current TP. */ csrrw tp, {csr_scratch}, tp bnez tp, _save_context /* 从内核态进入中断 */ j {_restore_kernel_tpsp} "), csr_scratch = const CSR_SSCRATCH, _restore_kernel_tpsp = sym _restore_kernel_tpsp ) } #[naked] #[no_mangle] unsafe extern "C" fn _restore_kernel_tpsp() -> ! { core::arch::naked_asm!( concat!(" // 这次是从内核态进入中断 // 从sscratch寄存器加载当前cpu的上下文 csrr tp, {csr_scratch} // 把当前的sp寄存器的值保存到当前cpu的上下文的kernel_sp字段 sd sp, {lc_off_kernel_sp}(tp) j {_save_context} "), csr_scratch = const CSR_SSCRATCH, lc_off_kernel_sp = const offset_of!(LocalContext, kernel_sp), _save_context = sym _save_context ) } #[naked] #[no_mangle] unsafe extern "C" fn _save_context() -> ! { core::arch::naked_asm!( concat!(" // 保存当前cpu的上下文 // 保存用户sp sd sp, {lc_off_user_sp}(tp) // 加载内核sp ld sp, {lc_off_kernel_sp}(tp) addi sp, sp, -{trap_frame_size_on_stack} sd x1, {off_ra}(sp) sd x3, {off_gp}(sp) sd x5, {off_t0}(sp) ", save_from_x6_to_x31!(), " /* * Disable user-mode memory access as it should only be set in the * actual user copy routines. * * Disable the FPU/Vector to detect illegal usage of floating point * or vector in kernel space. */ li t0, {sr_sum_and_fsvs} ld s0, {lc_off_user_sp}(tp) csrrc s1, {csr_status}, t0 csrr s2, {csr_epc} csrr s3, {csr_tval} csrr s4, {csr_cause} csrr s5, {csr_scratch} sd s0, {off_sp}(sp) sd s1, {off_status}(sp) sd s2, {off_epc}(sp) sd s3, {off_badaddr}(sp) sd s4, {off_cause}(sp) sd s5, {off_tp}(sp) /* * Set the scratch register to 0, so that if a recursive exception * occurs, the exception vector knows it came from the kernel */ csrw {csr_scratch}, x0 /* Load the global pointer */ // linux 加载了global pointer,但是我们暂时没有用到 // .option push // .option norelax // la gp, __global_pointer$ // .option pop mv a0, sp la ra, ret_from_exception tail riscv64_do_irq " ), lc_off_user_sp = const offset_of!(LocalContext, user_sp), lc_off_kernel_sp = const offset_of!(LocalContext, kernel_sp), trap_frame_size_on_stack = const TrapFrame::SIZE_ON_STACK, off_ra = const offset_of!(TrapFrame, ra), off_gp = const offset_of!(TrapFrame, gp), off_t0 = const offset_of!(TrapFrame, t0), off_t1 = const offset_of!(TrapFrame, t1), off_t2 = const offset_of!(TrapFrame, t2), off_s0 = const offset_of!(TrapFrame, s0), off_s1 = const offset_of!(TrapFrame, s1), off_a0 = const offset_of!(TrapFrame, a0), off_a1 = const offset_of!(TrapFrame, a1), off_a2 = const offset_of!(TrapFrame, a2), off_a3 = const offset_of!(TrapFrame, a3), off_a4 = const offset_of!(TrapFrame, a4), off_a5 = const offset_of!(TrapFrame, a5), off_a6 = const offset_of!(TrapFrame, a6), off_a7 = const offset_of!(TrapFrame, a7), off_s2 = const offset_of!(TrapFrame, s2), off_s3 = const offset_of!(TrapFrame, s3), off_s4 = const offset_of!(TrapFrame, s4), off_s5 = const offset_of!(TrapFrame, s5), off_s6 = const offset_of!(TrapFrame, s6), off_s7 = const offset_of!(TrapFrame, s7), off_s8 = const offset_of!(TrapFrame, s8), off_s9 = const offset_of!(TrapFrame, s9), off_s10 = const offset_of!(TrapFrame, s10), off_s11 = const offset_of!(TrapFrame, s11), off_t3 = const offset_of!(TrapFrame, t3), off_t4 = const offset_of!(TrapFrame, t4), off_t5 = const offset_of!(TrapFrame, t5), off_t6 = const offset_of!(TrapFrame, t6), off_sp = const offset_of!(TrapFrame, sp), off_status = const offset_of!(TrapFrame, status), off_badaddr = const offset_of!(TrapFrame, badaddr), off_cause = const offset_of!(TrapFrame, cause), off_tp = const offset_of!(TrapFrame, tp), off_epc = const offset_of!(TrapFrame, epc), sr_sum_and_fsvs = const (0), // 暂时在内核中不禁用FPU和Vector，以及不禁用用户内存访问 // sr_sum_and_fsvs = const (SR_FS_VS | SR_SUM), csr_status = const CSR_SSTATUS, csr_epc = const CSR_SEPC, csr_tval = const CSR_STVAL, csr_cause = const CSR_SCAUSE, csr_scratch = const CSR_SSCRATCH ) } #[naked] #[no_mangle] pub unsafe extern "C" fn ret_from_exception() -> ! { core::arch::naked_asm!( concat!(" ld s0, {off_status}(sp) andi s0, s0, {sr_spp} bnez s0, 3f // Save unwound kernel stack pointer in thread_info addi s0, sp, {trap_frame_size_on_stack} sd s0, {lc_off_kernel_sp}(tp) /* * Save TP into the scratch register , so we can find the kernel data * structures again. */ csrw {csr_scratch}, tp 3: ld a0, {off_status}(sp) ld a2, {off_epc}(sp) sc.d x0, a2, {off_epc}(sp) csrw {csr_status}, a0 csrw {csr_epc}, a2 ld x1, {off_ra}(sp) ld x3, {off_gp}(sp) ld x4, {off_tp}(sp) ld x5, {off_t0}(sp) ", restore_from_x6_to_x31!(), " ld x2, {off_sp}(sp) sret " ), off_status = const offset_of!(TrapFrame, status), sr_spp = const SR_SPP, trap_frame_size_on_stack = const TrapFrame::SIZE_ON_STACK, lc_off_kernel_sp = const offset_of!(LocalContext, kernel_sp), csr_scratch = const CSR_SSCRATCH, csr_status = const CSR_SSTATUS, csr_epc = const CSR_SEPC, off_ra = const offset_of!(TrapFrame, ra), off_gp = const offset_of!(TrapFrame, gp), off_t0 = const offset_of!(TrapFrame, t0), off_t1 = const offset_of!(TrapFrame, t1), off_t2 = const offset_of!(TrapFrame, t2), off_s0 = const offset_of!(TrapFrame, s0), off_s1 = const offset_of!(TrapFrame, s1), off_a0 = const offset_of!(TrapFrame, a0), off_a1 = const offset_of!(TrapFrame, a1), off_a2 = const offset_of!(TrapFrame, a2), off_a3 = const offset_of!(TrapFrame, a3), off_a4 = const offset_of!(TrapFrame, a4), off_a5 = const offset_of!(TrapFrame, a5), off_a6 = const offset_of!(TrapFrame, a6), off_a7 = const offset_of!(TrapFrame, a7), off_s2 = const offset_of!(TrapFrame, s2), off_s3 = const offset_of!(TrapFrame, s3), off_s4 = const offset_of!(TrapFrame, s4), off_s5 = const offset_of!(TrapFrame, s5), off_s6 = const offset_of!(TrapFrame, s6), off_s7 = const offset_of!(TrapFrame, s7), off_s8 = const offset_of!(TrapFrame, s8), off_s9 = const offset_of!(TrapFrame, s9), off_s10 = const offset_of!(TrapFrame, s10), off_s11 = const offset_of!(TrapFrame, s11), off_t3 = const offset_of!(TrapFrame, t3), off_t4 = const offset_of!(TrapFrame, t4), off_t5 = const offset_of!(TrapFrame, t5), off_t6 = const offset_of!(TrapFrame, t6), off_sp = const offset_of!(TrapFrame, sp), off_tp = const offset_of!(TrapFrame, tp), off_epc = const offset_of!(TrapFrame, epc) ) }