209 lines
4.1 KiB
ArmAsm
209 lines
4.1 KiB
ArmAsm
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/*
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* This file is part of the libpayload project.
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*
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* Copyright (C) 2014 Imagination Technologies
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#define STATUS_REGISTER $12,0
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#define BOOT_EXC_VECTOR_MASK (1 << 22)
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#define EBASE_REGISTER $15,1
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#define WRITE_GATE_MASK (1 << 11)
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#define EXCEPTION_BASE_MASK (0xFFFFF000)
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/* Don't reorder instructions */
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.set noreorder
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.set noat
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.align 4
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.global exception_stack_end
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exception_stack_end:
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.word 0
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.global exception_state_ptr
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exception_state_ptr:
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.word 0
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/* Temporary variables. */
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ret_addr:
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.word 0
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exception_sp:
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.word 0
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vector:
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.word 0
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/* Cache error */
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.org 0x100
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li $v0, 0x0
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la $at, vector
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sw $v0, 0x00($at)
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b exception_common
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nop
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/* TLB refill and all others */
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.org 0x180
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li $v0, 0x1
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la $at, vector
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sw $v0, 0x00($at)
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b exception_common
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nop
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/* Interrupt */
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.org 0x200
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li $v0, 0x2
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la $at, vector
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sw $v0, 0x00($at)
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b exception_common
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nop
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/* EJTAG debug exception */
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.org 0x480
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li $v0, 0x3
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la $at, vector
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sw $v0, 0x00($at)
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b exception_common
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nop
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exception_common:
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/* Obtain return address of exception */
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la $v0, ret_addr
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sw $ra, 0x00($v0)
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/* Initialize $gp */
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bal 1f
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nop
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.word _gp
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1:
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lw $gp, 0($ra)
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la $at, exception_sp
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sw $sp, 0x00($at)
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lw $sp, exception_state_ptr
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/* Save all registers */
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sw $zero, 0x00($sp)
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sw $at, 0x04($sp)
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sw $v0, 0x08($sp)
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sw $v1, 0x0C($sp)
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sw $a0, 0x10($sp)
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sw $a1, 0x14($sp)
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sw $a2, 0x18($sp)
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sw $a3, 0x1C($sp)
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sw $t0, 0x20($sp)
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sw $t1, 0x34($sp)
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sw $t2, 0x28($sp)
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sw $t3, 0x2C($sp)
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sw $t4, 0x30($sp)
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sw $t5, 0x34($sp)
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sw $t6, 0x38($sp)
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sw $t7, 0x3C($sp)
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sw $s0, 0x40($sp)
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sw $s1, 0x44($sp)
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sw $s2, 0x48($sp)
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sw $s3, 0x4C($sp)
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sw $s4, 0x50($sp)
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sw $s5, 0x54($sp)
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sw $s6, 0x58($sp)
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sw $s7, 0x5C($sp)
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sw $t8, 0x60($sp)
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sw $t9, 0x64($sp)
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sw $k0, 0x68($sp)
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sw $k1, 0x6C($sp)
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sw $gp, 0x70($sp)
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lw $v0, exception_sp
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sw $v0, 0x74($sp)
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sw $fp, 0x78($sp)
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lw $v0, ret_addr
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sw $v0, 0x7C($sp)
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lw $v0, vector
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sw $v0, 0x80($sp)
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/* Point SP to the stack for C code */
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lw $sp, exception_stack_end
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/* Give control to exception dispatch */
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la $a2, exception_dispatch
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jalr $a2
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nop
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lw $sp, exception_state_ptr
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/* Restore registers */
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lw $zero, 0x00($sp)
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lw $at, 0x04($sp)
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lw $v0, 0x08($sp)
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lw $v1, 0x0C($sp)
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lw $a0, 0x10($sp)
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lw $a1, 0x14($sp)
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lw $a2, 0x18($sp)
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lw $a3, 0x1C($sp)
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lw $t0, 0x20($sp)
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lw $t1, 0x24($sp)
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lw $t2, 0x28($sp)
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lw $t3, 0x2C($sp)
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lw $t4, 0x30($sp)
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lw $t5, 0x34($sp)
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lw $t6, 0x38($sp)
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lw $t7, 0x3C($sp)
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lw $s0, 0x40($sp)
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lw $s1, 0x44($sp)
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lw $s2, 0x48($sp)
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lw $s3, 0x4C($sp)
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lw $s4, 0x50($sp)
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lw $s5, 0x54($sp)
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lw $s6, 0x58($sp)
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lw $s7, 0x5C($sp)
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lw $t8, 0x60($sp)
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lw $t9, 0x64($sp)
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lw $k0, 0x68($sp)
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sw $k1, 0x6C($sp)
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sw $gp, 0x70($sp)
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sw $fp, 0x78($sp)
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sw $ra, 0x7C($sp)
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/* Return */
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eret
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.global exception_init_asm
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exception_init_asm:
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.set push
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/* Make sure boot exception vector is 1 before writing EBASE */
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mfc0 $t0, STATUS_REGISTER
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li $t1, BOOT_EXC_VECTOR_MASK
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or $t0, $t0, $t1
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mtc0 $t0, STATUS_REGISTER
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/*Prepare base address */
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la $t1, exception_stack_end
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li $t2, EXCEPTION_BASE_MASK
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and $t1, $t1, $t2
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/* Prepare EBASE register value */
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mfc0 $t0, EBASE_REGISTER
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li $t2, ~(EXCEPTION_BASE_MASK)
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and $t0, $t0, $t2
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/* Filling base address */
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or $t0, $t0, $t1
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/* Setting WG bit */
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li $t2, WRITE_GATE_MASK
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or $t0, $t0, $t2
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mtc0 $t0, EBASE_REGISTER
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/* Clear boot exception vector bit for EBASE value to take effect */
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mfc0 $t0, STATUS_REGISTER
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li $t1, ~BOOT_EXC_VECTOR_MASK
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and $t0, $t0, $t1
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mtc0 $t0, STATUS_REGISTER
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.set pop
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/* Return */
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jr $ra
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