esp-idf/components/riscv/vectors.S

311 lines
9.9 KiB
ArmAsm

/*
* SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "soc/soc.h"
#include "soc/interrupt_reg.h"
#include "riscv/rvruntime-frames.h"
#include "soc/soc_caps.h"
#include "sdkconfig.h"
.equ SAVE_REGS, 32
.equ CONTEXT_SIZE, (SAVE_REGS * 4)
.equ panic_from_exception, xt_unhandled_exception
.equ panic_from_isr, panicHandler
/* Macro which first allocates space on the stack to save general
* purpose registers, and then save them. GP register is excluded.
* The default size allocated on the stack is CONTEXT_SIZE, but it
* can be overridden. */
.macro save_general_regs cxt_size=CONTEXT_SIZE
addi sp, sp, -\cxt_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
/* Restore the general purpose registers (excluding gp) from the context on
* the stack. The context is then deallocated. The default size is CONTEXT_SIZE
* but it can be overriden. */
.macro restore_general_regs cxt_size=CONTEXT_SIZE
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, \cxt_size
.endm
.macro restore_mepc
lw t0, RV_STK_MEPC(sp)
csrw mepc, t0
.endm
.global rtos_int_enter
.global rtos_int_exit
.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)*/
#ifdef CONFIG_ESP_SYSTEM_MEMPROT_FEATURE
j _panic_handler /* Call panic handler for ETS_MEMPROT_ERR_INUM interrupt (soc-level panic)*/
.rept (ETS_MAX_INUM - ETS_MEMPROT_ERR_INUM)
#else
.rept (ETS_MAX_INUM - ETS_CACHEERR_INUM)
#endif //CONFIG_ESP_SYSTEM_MEMPROT_FEATURE
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:
/* Allocate space on the stack and store general purpose registers */
save_general_regs RV_STK_FRMSZ
/* As gp register is not saved by the macro, save it here */
sw gp, RV_STK_GP(sp)
/* Same goes for the SP value before trapping */
addi t0, sp, RV_STK_FRMSZ /* restore sp with the value when trap happened */
/* Save CSRs */
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 */
jal panic_from_exception
/* We arrive here if the exception handler has returned. */
j _return_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)
jal panic_from_isr
/* We arrive here if the exception handler has returned. This means that
* the exception was handled, and the execution flow should resume.
* Restore the registers and return from the exception.
*/
_return_from_exception:
restore_mepc
/* MTVEC and SP are assumed to be unmodified.
* MSTATUS, MHARTID, MTVAL are read-only and not restored.
*/
lw gp, RV_STK_GP(sp)
restore_general_regs RV_STK_FRMSZ
mret
.size _panic_handler, .-_panic_handler
/* 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:
/* Start by saving the general purpose registers and the PC value before
* the interrupt happened. */
save_general_regs
save_mepc
/* Though it is not necessary we save GP and SP here.
* SP is necessary to help GDB to properly unwind
* the backtrace of threads preempted by interrupts (OS tick etc.).
* GP is saved just to have its proper value in GDB. */
/* As gp register is not saved by the macro, save it here */
sw gp, RV_STK_GP(sp)
/* Same goes for the SP value before trapping */
addi t0, sp, CONTEXT_SIZE /* restore sp with the value when interrupt happened */
/* Save SP */
sw t0, RV_STK_SP(sp)
/* Before doing anythig preserve the stack pointer */
/* It will be saved in current TCB, if needed */
mv a0, sp
call rtos_int_enter
/* If this is a non-nested interrupt, SP now points to the interrupt stack */
/* 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
/* MIE set. Nested interrupts can now occur */
#ifdef CONFIG_PM_TRACE
li a0, 0 /* = ESP_PM_TRACE_IDLE */
#if SOC_CPU_CORES_NUM == 1
li a1, 0 /* No need to check core ID on single core hardware */
#else
csrr a1, mhartid
#endif
la t0, esp_pm_trace_exit
jalr t0 /* absolute jump, avoid the 1 MiB range constraint */
#endif
#ifdef CONFIG_PM_ENABLE
la t0, esp_pm_impl_isr_hook
jalr t0 /* absolute jump, avoid the 1 MiB range constraint */
#endif
/* call the C dispatcher */
mv a0, sp /* argument 1, stack pointer */
mv a1, s1 /* argument 2, interrupt number (mcause) */
/* 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 */
li t0, 0x8
csrrc t0, mstatus, t0
/* MIE cleared. Nested interrupts are disabled */
/* 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
/* If this is a non-nested interrupt, context switch called, SP now points to back to task stack. */
/* 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_general_regs
/* exit, this will also re-enable the interrupts */
mret
.size _interrupt_handler, .-_interrupt_handler