/* * Copyright (c) 2006-2020, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2018-12-10 Jesven first version * 2021-02-03 lizhirui port to riscv64 * 2021-02-19 lizhirui port to new version of rt-smart * 2022-11-08 Wangxiaoyao Cleanup codes; * Support new context switch * 2023-07-16 Shell Move part of the codes to C from asm in signal handling */ #include "rtconfig.h" #ifndef __ASSEMBLY__ #define __ASSEMBLY__ #endif /* __ASSEMBLY__ */ #include "cpuport.h" #include "encoding.h" #include "stackframe.h" #include "asm-generic.h" .section .text.lwp /* * void arch_start_umode(args, text, ustack, kstack); */ .global arch_start_umode .type arch_start_umode, % function arch_start_umode: // load kstack for user process csrw sscratch, a3 li t0, SSTATUS_SPP | SSTATUS_SIE // set as user mode, close interrupt csrc sstatus, t0 li t0, SSTATUS_SPIE // enable interrupt when return to user mode csrs sstatus, t0 csrw sepc, a1 mv a3, a2 sret//enter user mode /* * void arch_crt_start_umode(args, text, ustack, kstack); */ .global arch_crt_start_umode .type arch_crt_start_umode, % function arch_crt_start_umode: li t0, SSTATUS_SPP | SSTATUS_SIE // set as user mode, close interrupt csrc sstatus, t0 li t0, SSTATUS_SPIE // enable interrupt when return to user mode csrs sstatus, t0 csrw sepc, a1 mv s0, a0 mv s1, a1 mv s2, a2 mv s3, a3 mv a0, s2 call lwp_copy_return_code_to_user_stack mv a0, s2 call lwp_fix_sp mv sp, a0//user_sp mv ra, a0//return address mv a0, s0//args csrw sscratch, s3 sret//enter user mode /** * Unify exit point from kernel mode to enter user space * we handle following things here: * 1. restoring user mode debug state (not support yet) * 2. handling thread's exit request * 3. handling POSIX signal * 4. restoring user context * 5. jump to user mode */ .global arch_ret_to_user arch_ret_to_user: // TODO: we don't support kernel gdb server in risc-v yet // so we don't check debug state here and handle debugging bussiness call lwp_check_exit_request beqz a0, 1f mv a0, x0 call sys_exit 1: mv a0, sp call lwp_thread_signal_catch ret_to_user_exit: RESTORE_ALL // `RESTORE_ALL` also reset sp to user sp, and setup sscratch sret /** * Restore user context from exception frame stroraged in ustack * And handle pending signals; */ arch_signal_quit: LOAD a0, FRAME_OFF_SP(sp) call arch_signal_ucontext_restore /* reset kernel sp to the stack */ STORE sp, FRAME_OFF_SP(a0) /* return value is user sp */ mv sp, a0 /* restore user sp before enter trap */ addi a0, sp, CTX_REG_NR * REGBYTES csrw sscratch, a0 RESTORE_ALL SAVE_ALL j arch_ret_to_user /** * rt_noreturn * void arch_thread_signal_enter( * int signo, -> a0 * siginfo_t *psiginfo, -> a1 * void *exp_frame, -> a2 * void *entry_uaddr, -> a3 * lwp_sigset_t *save_sig_mask, -> a4 * ) */ .global arch_thread_signal_enter arch_thread_signal_enter: mv s3, a2 mv s2, a0 mv s1, a3 LOAD t0, FRAME_OFF_SP(a2) mv a3, t0 call arch_signal_ucontext_save /** restore kernel sp */ addi sp, s3, CTX_REG_NR * REGBYTES /** * set regiter RA to user signal handler * set sp to user sp & save kernel sp in sscratch */ mv ra, a0 csrw sscratch, sp mv sp, a0 /** * s1 is signal_handler, * s1 = !s1 ? lwp_sigreturn : s1; */ bnez s1, 1f mv s1, ra 1: /* enter user mode and enable interrupt when return to user mode */ li t0, SSTATUS_SPP csrc sstatus, t0 li t0, SSTATUS_SPIE csrs sstatus, t0 /* sepc <- signal_handler */ csrw sepc, s1 /* a0 <- signal id */ mv a0, s2 /* a1 <- siginfo */ add a1, sp, 16 /* dummy a2 */ mv a2, a1 /** * handler(signo, psi, ucontext); */ sret .align 3 lwp_debugreturn: li a7, 0xff ecall .align 3 .global lwp_sigreturn lwp_sigreturn: li a7, 0xfe ecall .align 3 lwp_sigreturn_end: .align 3 .global lwp_thread_return lwp_thread_return: li a0, 0 li a7, 1 ecall .align 3 .global lwp_thread_return_end lwp_thread_return_end: .globl arch_get_tidr arch_get_tidr: mv a0, tp ret .global arch_set_thread_area arch_set_thread_area: .globl arch_set_tidr arch_set_tidr: mv tp, a0 ret .global arch_clone_exit .global arch_fork_exit arch_fork_exit: arch_clone_exit: j arch_syscall_exit START_POINT(syscall_entry) #ifndef ARCH_USING_NEW_CTX_SWITCH //swap to thread kernel stack csrr t0, sstatus andi t0, t0, 0x100 beqz t0, __restore_sp_from_tcb __restore_sp_from_sscratch: // from kernel csrr t0, sscratch j __move_stack_context __restore_sp_from_tcb: // from user la a0, rt_current_thread LOAD a0, 0(a0) jal get_thread_kernel_stack_top mv t0, a0 __move_stack_context: mv t1, sp//src mv sp, t0//switch stack addi sp, sp, -CTX_REG_NR * REGBYTES //copy context li s0, CTX_REG_NR//cnt mv t2, sp//dst copy_context_loop: LOAD t0, 0(t1) STORE t0, 0(t2) addi s0, s0, -1 addi t1, t1, 8 addi t2, t2, 8 bnez s0, copy_context_loop #endif /* ARCH_USING_NEW_CTX_SWITCH */ /* fetch SYSCALL ID */ LOAD a7, 17 * REGBYTES(sp) addi a7, a7, -0xfe beqz a7, arch_signal_quit #ifdef ARCH_MM_MMU /* save setting when syscall enter */ call rt_thread_self call lwp_user_setting_save #endif mv a0, sp OPEN_INTERRUPT call syscall_handler j arch_syscall_exit START_POINT_END(syscall_entry) .global arch_syscall_exit arch_syscall_exit: CLOSE_INTERRUPT #if defined(ARCH_MM_MMU) LOAD s0, 2 * REGBYTES(sp) andi s0, s0, 0x100 bnez s0, dont_ret_to_user j arch_ret_to_user #endif dont_ret_to_user: #ifdef ARCH_MM_MMU /* restore setting when syscall exit */ call rt_thread_self call lwp_user_setting_restore /* after restore the reg `tp`, need modify context */ STORE tp, 4 * REGBYTES(sp) #endif //restore context RESTORE_ALL csrw sscratch, zero sret