esp-idf/components/riscv/vectors.S
Felipe Neves 810be86f21 freertos/riscv: move freertos aware interrupt code from vectors to the freertos riscv port.
The riscv vectors.S in riscv component contains the trap vector, which is responsible to
defer interrupts and examine if a task context switch is needed, this change cleans up
this code by hiding all freertos details behind on two functions rtos_it_enter/exit and
their implementations are placed in freertos riscv port files.
2021-01-05 15:39:46 +08:00

281 lines
7.6 KiB
ArmAsm

// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "soc/soc.h"
#include "soc/interrupt_reg.h"
#include "riscv/rvruntime-frames.h"
.equ SAVE_REGS, 32
.equ CONTEXT_SIZE, (SAVE_REGS * 4)
.equ panic_from_exception, xt_unhandled_exception
.equ panic_from_isr, panicHandler
.macro save_regs
addi sp, sp, -CONTEXT_SIZE
sw ra, RV_STK_RA(sp)
sw tp, RV_STK_TP(sp)
sw t0, RV_STK_T0(sp)
sw t1, RV_STK_T1(sp)
sw t2, RV_STK_T2(sp)
sw s0, RV_STK_S0(sp)
sw s1, RV_STK_S1(sp)
sw a0, RV_STK_A0(sp)
sw a1, RV_STK_A1(sp)
sw a2, RV_STK_A2(sp)
sw a3, RV_STK_A3(sp)
sw a4, RV_STK_A4(sp)
sw a5, RV_STK_A5(sp)
sw a6, RV_STK_A6(sp)
sw a7, RV_STK_A7(sp)
sw s2, RV_STK_S2(sp)
sw s3, RV_STK_S3(sp)
sw s4, RV_STK_S4(sp)
sw s5, RV_STK_S5(sp)
sw s6, RV_STK_S6(sp)
sw s7, RV_STK_S7(sp)
sw s8, RV_STK_S8(sp)
sw s9, RV_STK_S9(sp)
sw s10, RV_STK_S10(sp)
sw s11, RV_STK_S11(sp)
sw t3, RV_STK_T3(sp)
sw t4, RV_STK_T4(sp)
sw t5, RV_STK_T5(sp)
sw t6, RV_STK_T6(sp)
.endm
.macro save_mepc
csrr t0, mepc
sw t0, RV_STK_MEPC(sp)
.endm
.macro restore_regs
lw ra, RV_STK_RA(sp)
lw tp, RV_STK_TP(sp)
lw t0, RV_STK_T0(sp)
lw t1, RV_STK_T1(sp)
lw t2, RV_STK_T2(sp)
lw s0, RV_STK_S0(sp)
lw s1, RV_STK_S1(sp)
lw a0, RV_STK_A0(sp)
lw a1, RV_STK_A1(sp)
lw a2, RV_STK_A2(sp)
lw a3, RV_STK_A3(sp)
lw a4, RV_STK_A4(sp)
lw a5, RV_STK_A5(sp)
lw a6, RV_STK_A6(sp)
lw a7, RV_STK_A7(sp)
lw s2, RV_STK_S2(sp)
lw s3, RV_STK_S3(sp)
lw s4, RV_STK_S4(sp)
lw s5, RV_STK_S5(sp)
lw s6, RV_STK_S6(sp)
lw s7, RV_STK_S7(sp)
lw s8, RV_STK_S8(sp)
lw s9, RV_STK_S9(sp)
lw s10, RV_STK_S10(sp)
lw s11, RV_STK_S11(sp)
lw t3, RV_STK_T3(sp)
lw t4, RV_STK_T4(sp)
lw t5, RV_STK_T5(sp)
lw t6, RV_STK_T6(sp)
addi sp, sp, CONTEXT_SIZE
.endm
.macro restore_mepc
lw t0, RV_STK_MEPC(sp)
csrw mepc, t0
.endm
.global rtos_int_enter
.global rtos_int_exit
.global uxInterruptNesting
.global _global_interrupt_handler
.section .exception_vectors.text
/* This is the vector table. MTVEC points here.
*
* Use 4-byte intructions here. 1 instruction = 1 entry of the table.
* The CPU jumps to MTVEC (i.e. the first entry) in case of an exception,
* and (MTVEC & 0xfffffffc) + (mcause & 0x7fffffff) * 4, in case of an interrupt.
*
* Note: for our CPU, we need to place this on a 256-byte boundary, as CPU
* only uses the 24 MSBs of the MTVEC, i.e. (MTVEC & 0xffffff00).
*/
.balign 0x100
.global _vector_table
.type _vector_table, @function
_vector_table:
.option push
.option norvc
j _panic_handler /* exception handler, entry 0 */
.rept (ETS_T1_WDT_INUM - 1)
j _interrupt_handler /* 24 identical entries, all pointing to the interrupt handler */
.endr
j _panic_handler /* Call panic handler for ETS_T1_WDT_INUM interrupt (soc-level panic)*/
j _panic_handler /* Call panic handler for ETS_CACHEERR_INUM interrupt (soc-level panic)*/
.rept (ETS_MAX_INUM - ETS_CACHEERR_INUM)
j _interrupt_handler /* 6 identical entries, all pointing to the interrupt handler */
.endr
.option pop
.size _vector_table, .-_vector_table
/* Exception handler.*/
.type _panic_handler, @function
_panic_handler:
addi sp, sp, -RV_STK_FRMSZ /* allocate space on stack to store necessary registers */
/* save general registers */
sw ra, RV_STK_RA(sp)
sw gp, RV_STK_GP(sp)
sw tp, RV_STK_TP(sp)
sw t0, RV_STK_T0(sp)
sw t1, RV_STK_T1(sp)
sw t2, RV_STK_T2(sp)
sw s0, RV_STK_S0(sp)
sw s1, RV_STK_S1(sp)
sw a0, RV_STK_A0(sp)
sw a1, RV_STK_A1(sp)
sw a2, RV_STK_A2(sp)
sw a3, RV_STK_A3(sp)
sw a4, RV_STK_A4(sp)
sw a5, RV_STK_A5(sp)
sw a6, RV_STK_A6(sp)
sw a7, RV_STK_A7(sp)
sw s2, RV_STK_S2(sp)
sw s3, RV_STK_S3(sp)
sw s4, RV_STK_S4(sp)
sw s5, RV_STK_S5(sp)
sw s6, RV_STK_S6(sp)
sw s7, RV_STK_S7(sp)
sw s8, RV_STK_S8(sp)
sw s9, RV_STK_S9(sp)
sw s10, RV_STK_S10(sp)
sw s11, RV_STK_S11(sp)
sw t3, RV_STK_T3(sp)
sw t4, RV_STK_T4(sp)
sw t5, RV_STK_T5(sp)
sw t6, RV_STK_T6(sp)
addi t0, sp, RV_STK_FRMSZ /* restore sp with the value when trap happened */
sw t0, RV_STK_SP(sp)
csrr t0, mepc
sw t0, RV_STK_MEPC(sp)
csrr t0, mstatus
sw t0, RV_STK_MSTATUS(sp)
csrr t0, mtvec
sw t0, RV_STK_MTVEC(sp)
csrr t0, mtval
sw t0, RV_STK_MTVAL(sp)
csrr t0, mhartid
sw t0, RV_STK_MHARTID(sp)
/* Call panic_from_exception(sp) or panic_from_isr(sp)
* depending on whether we have a pseudo excause or not.
* If mcause's highest bit is 1, then an interrupt called this routine,
* so we have a pseudo excause. Else, it is due to a exception, we don't
* have an pseudo excause */
mv a0, sp
csrr a1, mcause
/* Branches instructions don't accept immediates values, so use t1 to
* store our comparator */
li t0, 0x80000000
bgeu a1, t0, _call_panic_handler
sw a1, RV_STK_MCAUSE(sp)
/* exception_from_panic never returns */
j panic_from_exception
_call_panic_handler:
/* Remove highest bit from mcause (a1) register and save it in the
* structure */
not t0, t0
and a1, a1, t0
sw a1, RV_STK_MCAUSE(sp)
/* exception_from_isr never returns */
j panic_from_isr
.size panic_from_isr, .-panic_from_isr
/* This is the interrupt handler.
* It saves the registers on the stack,
* prepares for interrupt nesting,
* re-enables the interrupts,
* then jumps to the C dispatcher in interrupt.c.
*/
.global _interrupt_handler
.type _interrupt_handler, @function
_interrupt_handler:
/* entry */
save_regs
save_mepc
/* Before doing anythig preserve the stack pointer */
/* It will be saved in current TCB, if needed */
mv a0, sp
call rtos_int_enter
/* Before dispatch c handler, restore interrupt to enable nested intr */
csrr s1, mcause
csrr s2, mstatus
/* Save the interrupt threshold level */
la t0, INTERRUPT_CORE0_CPU_INT_THRESH_REG
lw s3, 0(t0)
/* Increase interrupt threshold level */
li t2, 0x7fffffff
and t1, s1, t2 /* t1 = mcause & mask */
slli t1, t1, 2 /* t1 = mcause * 4 */
la t2, INTC_INT_PRIO_REG(0)
add t1, t2, t1 /* t1 = INTC_INT_PRIO_REG + 4 * mcause */
lw t2, 0(t1) /* t2 = INTC_INT_PRIO_REG[mcause] */
addi t2, t2, 1 /* t2 = t2 +1 */
sw t2, 0(t0) /* INTERRUPT_CORE0_CPU_INT_THRESH_REG = t2 */
fence
li t0, 0x8
csrrs t0, mstatus, t0
/* call the C dispatcher */
mv a0, sp /* argument 1, stack pointer */
csrr a1, mcause /* argument 2, interrupt number */
/* mask off the interrupt flag of mcause */
li t0, 0x7fffffff
and a1, a1, t0
jal _global_interrupt_handler
/* After dispatch c handler, disable interrupt to make freertos make context switch */
la t0, 0x8
csrrc t0, mstatus, t0
/* restore the interrupt threshold level */
la t0, INTERRUPT_CORE0_CPU_INT_THRESH_REG
sw s3, 0(t0)
fence
/* Yield to the next task is needed: */
mv a0, sp
call rtos_int_exit
/* The next (or current) stack pointer is returned in a0 */
mv sp, a0
/* restore the rest of the registers */
csrw mcause, s1
csrw mstatus, s2
restore_mepc
restore_regs
/* exit, this will also re-enable the interrupts */
mret
.size _interrupt_handler, .-_interrupt_handler