/** * @file * * @ingroup ScoreCPU * * @brief RISC-V exception support implementation. */ /* * Copyright (c) 2018 embedded brains GmbH * Copyright (c) 2015 University of York. * Hesham Almatary * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include EXTERN(bsp_start_vector_table_begin) EXTERN(_Thread_Dispatch) PUBLIC(ISR_Handler) .section .text, "ax", @progbits .align 2 TYPE_FUNC(ISR_Handler) SYM(ISR_Handler): addi sp, sp, -CPU_INTERRUPT_FRAME_SIZE /* Save */ SREG a0, RISCV_INTERRUPT_FRAME_A0(sp) SREG a1, RISCV_INTERRUPT_FRAME_A1(sp) SREG a2, RISCV_INTERRUPT_FRAME_A2(sp) SREG s0, RISCV_INTERRUPT_FRAME_S0(sp) csrr a0, mcause csrr a1, mstatus csrr a2, mepc GET_SELF_CPU_CONTROL s0 SREG s1, RISCV_INTERRUPT_FRAME_S1(sp) SREG ra, RISCV_INTERRUPT_FRAME_RA(sp) SREG a3, RISCV_INTERRUPT_FRAME_A3(sp) SREG a4, RISCV_INTERRUPT_FRAME_A4(sp) SREG a5, RISCV_INTERRUPT_FRAME_A5(sp) SREG a6, RISCV_INTERRUPT_FRAME_A6(sp) SREG a7, RISCV_INTERRUPT_FRAME_A7(sp) SREG t0, RISCV_INTERRUPT_FRAME_T0(sp) SREG t1, RISCV_INTERRUPT_FRAME_T1(sp) SREG t2, RISCV_INTERRUPT_FRAME_T2(sp) SREG t3, RISCV_INTERRUPT_FRAME_T3(sp) SREG t4, RISCV_INTERRUPT_FRAME_T4(sp) SREG t5, RISCV_INTERRUPT_FRAME_T5(sp) SREG t6, RISCV_INTERRUPT_FRAME_T6(sp) SREG a1, RISCV_INTERRUPT_FRAME_MSTATUS(sp) SREG a2, RISCV_INTERRUPT_FRAME_MEPC(sp) /* FIXME Only handle interrupts for now (MSB = 1) */ andi a0, a0, 0xf /* Increment interrupt nest and thread dispatch disable level */ lw t0, PER_CPU_ISR_NEST_LEVEL(s0) lw t1, PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(s0) addi t2, t0, 1 addi t1, t1, 1 sw t2, PER_CPU_ISR_NEST_LEVEL(s0) sw t1, PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(s0) /* Keep sp (Exception frame address) in s1 */ mv s1, sp /* Call the exception handler from vector table */ /* First function arg for C handler is vector number, * and the second is a pointer to exception frame. * a0/mcause/vector number is already loaded above */ mv a1, sp /* calculate the offset */ la t5, bsp_start_vector_table_begin #if __riscv_xlen == 32 slli t6, a0, 2 #else /* xlen = 64 */ slli t6, a0, 3 #endif add t5, t5, t6 LREG t5, (t5) /* Switch to interrupt stack if necessary */ bnez t0, .Linterrupt_stack_switch_done LREG sp, PER_CPU_INTERRUPT_STACK_HIGH(s0) .Linterrupt_stack_switch_done: jalr t5 /* Load some per-CPU variables */ lw t0, PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(s0) lbu t1, PER_CPU_DISPATCH_NEEDED(s0) lw t2, PER_CPU_ISR_DISPATCH_DISABLE(s0) lw t3, PER_CPU_ISR_NEST_LEVEL(s0) /* Restore stack pointer */ mv sp, s1 /* Decrement levels and determine thread dispatch state */ xor t1, t1, t0 addi t0, t0, -1 or t1, t1, t0 or t1, t1, t2 addi t3, t3, -1 /* Store thread dispatch disable and ISR nest levels */ sw t0, PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(s0) sw t3, PER_CPU_ISR_NEST_LEVEL(s0) /* * Check thread dispatch necessary, ISR dispatch disable and thread * dispatch disable level. */ bnez t1, .Lthread_dispatch_done .Ldo_thread_dispatch: /* Set ISR dispatch disable and thread dispatch disable level to one */ li t0, 1 sw t0, PER_CPU_ISR_DISPATCH_DISABLE(s0) sw t0, PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(s0) /* Call _Thread_Do_dispatch(), this function will enable interrupts */ mv a0, s0 li a1, RISCV_MSTATUS_MIE call _Thread_Do_dispatch /* Disable interrupts */ csrrc zero, mstatus, RISCV_MSTATUS_MIE #ifdef RTEMS_SMP GET_SELF_CPU_CONTROL s0 #endif /* Check if we have to do the thread dispatch again */ lbu t0, PER_CPU_DISPATCH_NEEDED(s0) bnez t0, .Ldo_thread_dispatch /* We are done with thread dispatching */ sw zero, PER_CPU_ISR_DISPATCH_DISABLE(s0) .Lthread_dispatch_done: /* Restore */ LREG a0, RISCV_INTERRUPT_FRAME_MSTATUS(sp) LREG a1, RISCV_INTERRUPT_FRAME_MEPC(sp) LREG a2, RISCV_INTERRUPT_FRAME_A2(sp) LREG s0, RISCV_INTERRUPT_FRAME_S0(sp) LREG s1, RISCV_INTERRUPT_FRAME_S1(sp) LREG ra, RISCV_INTERRUPT_FRAME_RA(sp) LREG a3, RISCV_INTERRUPT_FRAME_A3(sp) LREG a4, RISCV_INTERRUPT_FRAME_A4(sp) LREG a5, RISCV_INTERRUPT_FRAME_A5(sp) LREG a6, RISCV_INTERRUPT_FRAME_A6(sp) LREG a7, RISCV_INTERRUPT_FRAME_A7(sp) LREG t0, RISCV_INTERRUPT_FRAME_T0(sp) LREG t1, RISCV_INTERRUPT_FRAME_T1(sp) LREG t2, RISCV_INTERRUPT_FRAME_T2(sp) LREG t3, RISCV_INTERRUPT_FRAME_T3(sp) LREG t4, RISCV_INTERRUPT_FRAME_T4(sp) LREG t5, RISCV_INTERRUPT_FRAME_T5(sp) LREG t6, RISCV_INTERRUPT_FRAME_T6(sp) csrw mstatus, a0 csrw mepc, a1 LREG a0, RISCV_INTERRUPT_FRAME_A0(sp) LREG a1, RISCV_INTERRUPT_FRAME_A1(sp) addi sp, sp, CPU_INTERRUPT_FRAME_SIZE mret