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/*
* Early initialization code for RISC-V
*
* Copyright 2013 Google Inc.
* Copyright 2016 Jonathan Neuschäfer <j.neuschaefer@gmx.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; version 2 of
* the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
* GNU General Public License for more details.
*/
#include <arch/encoding.h>
#include <mcall.h>
.section ".text._start", "ax", %progbits
.globl _stack
.global _estack
.globl _start
_start:
# The boot ROM may pass the following arguments to coreboot:
# a0: the value of mhartid
# a1: a pointer to the flattened devicetree
#
# Preserve only the FDT pointer. We can query mhartid ourselves at any
# time.
#
csrw mscratch, a1
# initialize cache as ram
call cache_as_ram
# initialize stack point for each hart
# and the stack must be page-aligned.
# 0xDEADBEEF used to check stack overflow
csrr a0, mhartid
la t0, _stack
slli t1, a0, RISCV_PGSHIFT
add t0, t0, t1
li t1, 0xDEADBEEF
sd t1, 0(t0)
li t1, RISCV_PGSIZE - HLS_SIZE
add sp, t0, t1
# initialize hart-local storage
csrr a0, mhartid
call hls_init
# initialize entry of interrupt/exception
la t0, trap_entry
csrw mtvec, t0
# clear any pending interrupts
csrwi mip, 0
# set up the mstatus register for VM
call mstatus_init
tail main
// These codes need to be implemented on a specific SoC.
.weak cache_as_ram
cache_as_ram:
ret
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