/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2018/10/01 Bernard The first version * 2018/12/27 Jesven Add SMP support * 2020/6/12 Xim Port to QEMU and remove SMP support */ #define XSTATUS_FS (3 << 13) /* initial state of FPU, clear to disable */ #define XSTATUS_PUM (1 << 18) #include boot_hartid: .int .global boot_hartid .global _start .section ".start", "ax" _start: #ifdef RISCV_S_MODE # save hartid la t0, boot_hartid # global varible rt_boot_hartid mv t1, a0 # get hartid in S-mode frome a0 register sw t1, (t0) # store t1 register low 4 bits in memory address which is stored in t0 #else # setup stacks per hart csrr t0, mhartid # read current hart id slli t0, t0, 10 # shift left the hart id by 1024 # park harts with id != 0 csrr a0, mhartid # read current hart id bnez a0, park # if we're not on the hart 0 #endif csrw SRC_XIE, 0 # clear Interrupt Registers csrw SRC_XIP, 0 la t0, trap_entry csrw SRC_XTVEC, t0 # set Trap Vector Base Address Register /* set to disable FPU */ li t0, XSTATUS_FS # close fpu csrc SRC_XSTATUS, t0 #ifdef RISCV_S_MODE li t0, XSTATUS_PUM # PUM has no effect csrs SRC_XSTATUS, t0 #endif .option push .option norelax la gp, __global_pointer$ .option pop la sp, __stack_start__ li t0, __STACKSIZE__ add sp, sp, t0 csrw SRC_XSCRATCH, sp j primary_cpu_entry park: wfi j park