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/*
- FreeRTOS Kernel V10.3.1
- Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
- Permission is hereby granted, free of charge, to any person obtaining a copy of
- this software and associated documentation files (the “Software”), to deal in
- the Software without restriction, including without limitation the rights to
- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
- the Software, and to permit persons to whom the Software is furnished to do so,
- subject to the following conditions:
*
- The above copyright notice and this permission notice shall be included in all
- copies or substantial portions of the Software.
*
- THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
- IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- *
- 1 tab == 4 spaces!
*/
include “riscv_encoding.h”
ifndef __riscv_32e
define portRegNum 30
else
define portRegNum 14
endif
define portCONTEXT_SIZE ( portRegNum * REGBYTES )
.section .text.entry
.align 8
.extern switchTask
.extern getCurrentTaskStackTopAddr
.global prvPortStartFirstTask
/**
- brief Global interrupt disabled
- details
- This function disable global interrupt.
- remarks
- All the interrupt requests will be ignored by CPU.
*/
.macro DISABLE_MIE
csrc CSR_MSTATUS, MSTATUS_MIE
.endm
/**
- brief Macro for context save
- details
- This macro save ABI defined caller saved registers in the stack.
- remarks
- This Macro could use to save context when you enter to interrupt
- or exception
/
/ Save caller registers /
.macro SAVE_CONTEXT
csrrw sp, CSR_MSCRATCHCSWL, sp
/ Allocate stack space for context saving */
ifndef __riscv_32e
addi sp, sp, -20*REGBYTES
else
addi sp, sp, -14*REGBYTES
endif / __riscv_32e /
STORE x1, 0REGBYTES(sp)
STORE x4, 1REGBYTES(sp)
STORE x5, 2REGBYTES(sp)
STORE x6, 3REGBYTES(sp)
STORE x7, 4REGBYTES(sp)
STORE x10, 5REGBYTES(sp)
STORE x11, 6REGBYTES(sp)
STORE x12, 7REGBYTES(sp)
STORE x13, 8REGBYTES(sp)
STORE x14, 9REGBYTES(sp)
STORE x15, 10*REGBYTES(sp)
ifndef __riscv_32e
STORE x16, 14REGBYTES(sp)
STORE x17, 15REGBYTES(sp)
STORE x28, 16REGBYTES(sp)
STORE x29, 17REGBYTES(sp)
STORE x30, 18REGBYTES(sp)
STORE x31, 19REGBYTES(sp)
endif / __riscv_32e /
.endm
/**
- brief Macro for restore caller registers
- details
- This macro restore ABI defined caller saved registers from stack.
- remarks
- You could use this macro to restore context before you want return
- from interrupt or exeception
/
/ Restore caller registers /
.macro RESTORE_CONTEXT
LOAD x1, 0REGBYTES(sp)
LOAD x4, 1REGBYTES(sp)
LOAD x5, 2REGBYTES(sp)
LOAD x6, 3REGBYTES(sp)
LOAD x7, 4REGBYTES(sp)
LOAD x10, 5REGBYTES(sp)
LOAD x11, 6REGBYTES(sp)
LOAD x12, 7REGBYTES(sp)
LOAD x13, 8REGBYTES(sp)
LOAD x14, 9REGBYTES(sp)
LOAD x15, 10REGBYTES(sp)
ifndef __riscv_32e
LOAD x16, 14REGBYTES(sp)
LOAD x17, 15REGBYTES(sp)
LOAD x28, 16REGBYTES(sp)
LOAD x29, 17REGBYTES(sp)
LOAD x30, 18REGBYTES(sp)
LOAD x31, 19REGBYTES(sp)
/ De-allocate the stack space /
addi sp, sp, 20*REGBYTES
else
/ De-allocate the stack space /
addi sp, sp, 14*REGBYTES
endif / __riscv_32e /
csrrw sp, CSR_MSCRATCHCSWL, sp
.endm
/**
- brief Macro for save necessary CSRs to stack
- details
- This macro store MCAUSE, MEPC, MSUBM to stack.
/
.macro SAVE_CSR_CONTEXT
/ Store CSR mcause to stack using pushmcause /
csrrwi x0, CSR_PUSHMCAUSE, 11
/ Store CSR mepc to stack using pushmepc /
csrrwi x0, CSR_PUSHMEPC, 12
/ Store CSR msub to stack using pushmsub */
csrrwi x0, CSR_PUSHMSUBM, 13
.endm
/**
- brief Macro for restore necessary CSRs from stack
- details
- This macro restore MSUBM, MEPC, MCAUSE from stack.
/
.macro RESTORE_CSR_CONTEXT
LOAD x5, 13REGBYTES(sp)
csrw CSR_MSUBM, x5
LOAD x5, 12REGBYTES(sp)
csrw CSR_MEPC, x5
LOAD x5, 11REGBYTES(sp)
csrw CSR_MCAUSE, x5
.endm
/**
- brief Exception/NMI Entry
- details
- This function provide common entry functions for exception/nmi.
- remarks
- This function provide a default exception/nmi entry.
- ABI defined caller save register and some CSR registers
- to be saved before enter interrupt handler and be restored before return.
/
.section .text.trap
/ In CLIC mode, the exeception entry must be 64bytes aligned /
.align 6
.global exc_entry
exc_entry:
/ Save the caller saving registers (context) /
SAVE_CONTEXT
/ Save the necessary CSR registers */
SAVE_CSR_CONTEXT
/*
- Set the exception handler function arguments
- argument 1: mcause value
- argument 2: current stack point(SP) value
/
csrr a0, mcause
mv a1, sp
/
- TODO: Call the exception handler function
- By default, the function template is provided in
- system_Device.c, you can adjust it as you want
*/
call core_exception_handler
/ Restore the necessary CSR registers /
RESTORE_CSR_CONTEXT
/ Restore the caller saving registers (context) /
RESTORE_CONTEXT
/ Return to regular code /
mret
/**
- brief Non-Vector Interrupt Entry
- details
- This function provide common entry functions for handling
- non-vector interrupts
- remarks
- This function provide a default non-vector interrupt entry.
- ABI defined caller save register and some CSR registers need
- to be saved before enter interrupt handler and be restored before return.
/
.section .text.irq
/ In CLIC mode, the interrupt entry must be 4bytes aligned /
.align 2
.global irq_entry
/ This label will be set to MTVT2 register /
irq_entry:
/ Save the caller saving registers (context) /
SAVE_CONTEXT
/ Save the necessary CSR registers */
SAVE_CSR_CONTEXT
/* This special CSR read/write operation, which is actually
- claim the CLIC to find its pending highest ID, if the ID 模拟
- is not 0, then automatically enable the mstatus.MIE, and
- jump to its vector-entry-label, and update the link register
*/
csrrw ra, CSR_JALMNXTI, ra
/ Critical section with interrupts disabled /
DISABLE_MIE
/ Restore the necessary CSR registers /
RESTORE_CSR_CONTEXT
/ Restore the caller saving registers (context) /
RESTORE_CONTEXT
/ Return to regular code /
mret
/ Default Handler for Exceptions / Interrupts /
.global default_intexc_handler
Undef_Handler:
default_intexc_handler:
0
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