WebSVN – HelenOS-historic – Diff – /kernel/trunk/arch/mips32/src/start.S


#
# Copyright (C) 2003-2004 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
 
#include <arch/asm/regname.h>
#include <arch/mm/page.h>
#include <arch/asm/boot.h>
#include <arch/context_offset.h>
	
.text
 
.set noat
.set noreorder
.set nomacro
 
.global kernel_image_start
.global tlb_refill_entry
.global cache_error_entry
.global exception_entry
.global userspace_asm
 
# Which status bits should are thread-local
#define REG_SAVE_MASK 0x1f # KSU(UM), EXL, ERL, IE
	
# Save registers to space defined by \r
# We will change status: Disable ERL,EXL,UM,IE
# These changes will be automatically reversed in REGISTER_LOAD
# SP is NOT saved as part of these registers
.macro REGISTERS_STORE_AND_EXC_RESET r
	sw $at,EOFFSET_AT(\r)
	sw $v0,EOFFSET_V0(\r)
	sw $v1,EOFFSET_V1(\r)
	sw $a0,EOFFSET_A0(\r)
	sw $a1,EOFFSET_A1(\r)
	sw $a2,EOFFSET_A2(\r)
	sw $a3,EOFFSET_A3(\r)
	sw $t0,EOFFSET_T0(\r)
	sw $t1,EOFFSET_T1(\r)
	sw $t2,EOFFSET_T2(\r)
	sw $t3,EOFFSET_T3(\r)
	sw $t4,EOFFSET_T4(\r)
	sw $t5,EOFFSET_T5(\r)
	sw $t6,EOFFSET_T6(\r)
	sw $t7,EOFFSET_T7(\r)
	sw $t8,EOFFSET_T8(\r)
	sw $t9,EOFFSET_T9(\r)
 
	mflo $at
	sw $at, EOFFSET_LO(\r)
	mfhi $at
	sw $at, EOFFSET_HI(\r)
	
#ifdef CONFIG_DEBUG_ALLREGS	
	sw $s0,EOFFSET_S0(\r)
	sw $s1,EOFFSET_S1(\r)
	sw $s2,EOFFSET_S2(\r)
	sw $s3,EOFFSET_S3(\r)
	sw $s4,EOFFSET_S4(\r)
	sw $s5,EOFFSET_S5(\r)
	sw $s6,EOFFSET_S6(\r)
	sw $s7,EOFFSET_S7(\r)
	sw $s8,EOFFSET_S8(\r)
#endif
	
	sw $gp,EOFFSET_GP(\r)
	sw $ra,EOFFSET_RA(\r)
	sw $k1,EOFFSET_K1(\r)
 
	mfc0 $t0, $status
	mfc0 $t1, $epc
	
	and $t2, $t0, REG_SAVE_MASK  # Save only KSU,EXL,ERL,IE
	li $t3, ~(0x1f)
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL,IE
	
	sw $t2,EOFFSET_STATUS(\r)
	sw $t1,EOFFSET_EPC(\r)
	mtc0 $t0, $status
.endm
 
.macro REGISTERS_LOAD r
	# Update only UM,EXR,IE from status, the rest
	# is controlled by OS and not bound to task
	mfc0 $t0, $status
	lw $t1,EOFFSET_STATUS(\r)
 
	li $t2, ~REG_SAVE_MASK    # Mask UM,EXL,ERL,IE
	and $t0, $t0, $t2
	
	or $t0, $t0, $t1   # Copy UM,EXL,ERL,IE from saved status
	mtc0 $t0, $status
	
	lw $v0,EOFFSET_V0(\r)
	lw $v1,EOFFSET_V1(\r)
	lw $a0,EOFFSET_A0(\r)
	lw $a1,EOFFSET_A1(\r)
	lw $a2,EOFFSET_A2(\r)
	lw $a3,EOFFSET_A3(\r)
	lw $t0,EOFFSET_T0(\r)
	lw $t1,EOFFSET_T1(\r)
	lw $t2,EOFFSET_T2(\r)
	lw $t3,EOFFSET_T3(\r)
	lw $t4,EOFFSET_T4(\r)
	lw $t5,EOFFSET_T5(\r)
	lw $t6,EOFFSET_T6(\r)
	lw $t7,EOFFSET_T7(\r)
	lw $t8,EOFFSET_T8(\r)
	lw $t9,EOFFSET_T9(\r)
	
#ifdef CONFIG_DEBUG_ALLREGS	
	lw $s0,EOFFSET_S0(\r)
	lw $s1,EOFFSET_S1(\r)
	lw $s2,EOFFSET_S2(\r)
	lw $s3,EOFFSET_S3(\r)
	lw $s4,EOFFSET_S4(\r)
	lw $s5,EOFFSET_S5(\r)
	lw $s6,EOFFSET_S6(\r)
	lw $s7,EOFFSET_S7(\r)
	lw $s8,EOFFSET_S8(\r)
#endif
	lw $gp,EOFFSET_GP(\r)
	lw $ra,EOFFSET_RA(\r)
	lw $k1,EOFFSET_K1(\r)
	
	lw $at,EOFFSET_LO(\r)
	mtlo $at
	lw $at,EOFFSET_HI(\r)
	mthi $at
 
	lw $at,EOFFSET_EPC(\r)
	mtc0 $at, $epc
	
	lw $at,EOFFSET_AT(\r)
	lw $sp,EOFFSET_SP(\r)
.endm
 
# Move kernel stack pointer address to register K0
# - if we are in user mode, load the appropriate stack
# address
.macro KERNEL_STACK_TO_K0
	# If we are in user mode
	mfc0 $k0, $status
	andi $k0, 0x10
	
	beq $k0, $0, 1f
	add $k0, $sp, 0
	
	# Move $k0 pointer to kernel stack
	lui $k0, %hi(supervisor_sp)
	ori $k0, $k0, %lo(supervisor_sp)
	# Move $k0 (superveisor_sp)
	lw $k0, 0($k0)
1:		
.endm
		
.org 0x0
kernel_image_start:
	/* Load temporary stack */
	lui $sp, %hi(end_stack)
	ori $sp, $sp, %lo(end_stack)
 
	/* Not sure about this, but might be needed for PIC code???? */
	lui $gp, 0x8000
	
	jal arch_pre_main
	nop
	
	j main_bsp
	nop
 
	.space TEMP_STACK_SIZE
end_stack:
 
tlb_refill_entry:
	j tlb_refill_handler
	nop
 
cache_error_entry:
	j cache_error_handler
	nop
 
exception_entry:
	j exception_handler
	nop	
 
	
	
exception_handler:
	KERNEL_STACK_TO_K0
	sub $k0, REGISTER_SPACE
	sw $sp,EOFFSET_SP($k0)
	move $sp, $k0
	
	mfc0 $k0, $cause
	
	sra $k0, $k0, 0x2     # cp0_exc_cause() part 1
	andi $k0, $k0, 0x1f   # cp0_exc_cause() part 2
	sub $k0, 8            # 8=SYSCALL
	
	beqz $k0, syscall_shortcut
	add $k0, 8            # Revert $k1 back to correct exc number
	
	REGISTERS_STORE_AND_EXC_RESET $sp
	
	move $a1, $sp
	jal exc_dispatch      # exc_dispatch(excno, register_space)
	move $a0, $k0
 
	REGISTERS_LOAD $sp
	# The $sp is automatically restored to former value
	eret
 
# it seems that mips reserves some space on stack for varfuncs???
#define SS_ARG4   16
#define SS_SP     EOFFSET_SP
#define SS_STATUS EOFFSET_STATUS
#define SS_EPC    EOFFSET_EPC
syscall_shortcut:
	# We have a lot of space on the stack, with free use
	mfc0 $t1, $epc
	mfc0 $t0, $status
	sw $t1,SS_EPC($sp)  # Save EPC
	
	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
	li $t3, ~(0x1f)
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL
	ori $t0, $t0, 0x1           # Set IE
 
	sw $t2,SS_STATUS($sp)
	mtc0 $t0, $status
 
 
 
 
 
	# CALL Syscall handler
	jal syscall_handler
	sw $v0, SS_ARG4($sp)        # save v0 - arg4 to stack
 
 
	# restore status
	mfc0 $t0, $status
	lw $t1,SS_STATUS($sp)
 
	# Change back to EXL=1(from last exception), otherwise
	# an interrupt could rewrite the CP0-EPC
	li $t2, ~REG_SAVE_MASK      # Mask UM,EXL,ERL,IE
	and $t0, $t0, $t2
	or $t0, $t0, $t1            # Copy UM,EXL,ERL,IE from saved status
	mtc0 $t0, $status
			
	# restore epc+4
	lw $t0,SS_EPC($sp)
	addi $t0, $t0, 4
	mtc0 $t0, $epc
	
	lw $sp,SS_SP($sp) # restore sp
	
	eret
		
 
 
 
 
 
 
 
tlb_refill_handler:
	KERNEL_STACK_TO_K0
	sub $k0, REGISTER_SPACE
	REGISTERS_STORE_AND_EXC_RESET $k0
	sw $sp,EOFFSET_SP($k0)
	add $sp, $k0, 0
 
	add $a0, $sp, 0 
	jal tlb_refill /* tlb_refill(register_space) */
	nop
 
	REGISTERS_LOAD $sp
 
	eret
 
cache_error_handler:
	KERNEL_STACK_TO_K0
	sub $k0, REGISTER_SPACE
	REGISTERS_STORE_AND_EXC_RESET $k0
	sw $sp,EOFFSET_SP($k0)
	add $sp, $k0, 0
 
	jal cache_error
	nop
 
	REGISTERS_LOAD $sp
 
	eret
 
userspace_asm:
	add $sp, $a0, 0
	add $v0, $a1, 0 
	add $t9, $a2, 0   # Set up correct entry into PIC code 
	eret
 

Rev 1222	Rev 1278
1	#	1	#
2	# Copyright (C) 2003-2004 Jakub Jermar	2	# Copyright (C) 2003-2004 Jakub Jermar
3	# All rights reserved.	3	# All rights reserved.
4	#	4	#
5	# Redistribution and use in source and binary forms, with or without	5	# Redistribution and use in source and binary forms, with or without
6	# modification, are permitted provided that the following conditions	6	# modification, are permitted provided that the following conditions
7	# are met:	7	# are met:
8	#	8	#
9	# - Redistributions of source code must retain the above copyright	9	# - Redistributions of source code must retain the above copyright
10	# notice, this list of conditions and the following disclaimer.	10	# notice, this list of conditions and the following disclaimer.
11	# - Redistributions in binary form must reproduce the above copyright	11	# - Redistributions in binary form must reproduce the above copyright
12	# notice, this list of conditions and the following disclaimer in the	12	# notice, this list of conditions and the following disclaimer in the
13	# documentation and/or other materials provided with the distribution.	13	# documentation and/or other materials provided with the distribution.
14	# - The name of the author may not be used to endorse or promote products	14	# - The name of the author may not be used to endorse or promote products
15	# derived from this software without specific prior written permission.	15	# derived from this software without specific prior written permission.
16	#	16	#
17	# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	#	27	#
28		28
29	#include <arch/asm/regname.h>	29	#include <arch/asm/regname.h>
30	#include <arch/mm/page.h>	30	#include <arch/mm/page.h>
31	#include <arch/asm/boot.h>	31	#include <arch/asm/boot.h>
32	#include <arch/context_offset.h>	32	#include <arch/context_offset.h>
33		33
34	.text	34	.text
35		35
36	.set noat	36	.set noat
37	.set noreorder	37	.set noreorder
38	.set nomacro	38	.set nomacro
39		39
40	.global kernel_image_start	40	.global kernel_image_start
41	.global tlb_refill_entry	41	.global tlb_refill_entry
42	.global cache_error_entry	42	.global cache_error_entry
43	.global exception_entry	43	.global exception_entry
44	.global userspace_asm	44	.global userspace_asm
45		45
46	# Which status bits should are thread-local	46	# Which status bits should are thread-local
47	#define REG_SAVE_MASK 0x1f # KSU(UM), EXL, ERL, IE	47	#define REG_SAVE_MASK 0x1f # KSU(UM), EXL, ERL, IE
48		48
49	# Save registers to space defined by \r	49	# Save registers to space defined by \r
50	# We will change status: Disable ERL,EXL,UM,IE	50	# We will change status: Disable ERL,EXL,UM,IE
51	# These changes will be automatically reversed in REGISTER_LOAD	51	# These changes will be automatically reversed in REGISTER_LOAD
52	# SP is NOT saved as part of these registers	52	# SP is NOT saved as part of these registers
53	.macro REGISTERS_STORE_AND_EXC_RESET r	53	.macro REGISTERS_STORE_AND_EXC_RESET r
54	sw $at,EOFFSET_AT(\r)	54	sw $at,EOFFSET_AT(\r)
55	sw $v0,EOFFSET_V0(\r)	55	sw $v0,EOFFSET_V0(\r)
56	sw $v1,EOFFSET_V1(\r)	56	sw $v1,EOFFSET_V1(\r)
57	sw $a0,EOFFSET_A0(\r)	57	sw $a0,EOFFSET_A0(\r)
58	sw $a1,EOFFSET_A1(\r)	58	sw $a1,EOFFSET_A1(\r)
59	sw $a2,EOFFSET_A2(\r)	59	sw $a2,EOFFSET_A2(\r)
60	sw $a3,EOFFSET_A3(\r)	60	sw $a3,EOFFSET_A3(\r)
61	sw $t0,EOFFSET_T0(\r)	61	sw $t0,EOFFSET_T0(\r)
62	sw $t1,EOFFSET_T1(\r)	62	sw $t1,EOFFSET_T1(\r)
63	sw $t2,EOFFSET_T2(\r)	63	sw $t2,EOFFSET_T2(\r)
64	sw $t3,EOFFSET_T3(\r)	64	sw $t3,EOFFSET_T3(\r)
65	sw $t4,EOFFSET_T4(\r)	65	sw $t4,EOFFSET_T4(\r)
66	sw $t5,EOFFSET_T5(\r)	66	sw $t5,EOFFSET_T5(\r)
67	sw $t6,EOFFSET_T6(\r)	67	sw $t6,EOFFSET_T6(\r)
68	sw $t7,EOFFSET_T7(\r)	68	sw $t7,EOFFSET_T7(\r)
69	sw $t8,EOFFSET_T8(\r)	69	sw $t8,EOFFSET_T8(\r)
70	sw $t9,EOFFSET_T9(\r)	70	sw $t9,EOFFSET_T9(\r)
71		71
72	mflo $at	72	mflo $at
73	sw $at, EOFFSET_LO(\r)	73	sw $at, EOFFSET_LO(\r)
74	mfhi $at	74	mfhi $at
75	sw $at, EOFFSET_HI(\r)	75	sw $at, EOFFSET_HI(\r)
76		76
77	#ifdef CONFIG_DEBUG_ALLREGS	77	#ifdef CONFIG_DEBUG_ALLREGS
78	sw $s0,EOFFSET_S0(\r)	78	sw $s0,EOFFSET_S0(\r)
79	sw $s1,EOFFSET_S1(\r)	79	sw $s1,EOFFSET_S1(\r)
80	sw $s2,EOFFSET_S2(\r)	80	sw $s2,EOFFSET_S2(\r)
81	sw $s3,EOFFSET_S3(\r)	81	sw $s3,EOFFSET_S3(\r)
82	sw $s4,EOFFSET_S4(\r)	82	sw $s4,EOFFSET_S4(\r)
83	sw $s5,EOFFSET_S5(\r)	83	sw $s5,EOFFSET_S5(\r)
84	sw $s6,EOFFSET_S6(\r)	84	sw $s6,EOFFSET_S6(\r)
85	sw $s7,EOFFSET_S7(\r)	85	sw $s7,EOFFSET_S7(\r)
86	sw $s8,EOFFSET_S8(\r)	86	sw $s8,EOFFSET_S8(\r)
87	#endif	87	#endif
88		88
89	sw $gp,EOFFSET_GP(\r)	89	sw $gp,EOFFSET_GP(\r)
90	sw $ra,EOFFSET_RA(\r)	90	sw $ra,EOFFSET_RA(\r)
91	sw $k1,EOFFSET_K1(\r)	91	sw $k1,EOFFSET_K1(\r)
92		92
93	mfc0 $t0, $status	93	mfc0 $t0, $status
94	mfc0 $t1, $epc	94	mfc0 $t1, $epc
95		95
96	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE	96	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
97	li $t3, ~(0x1f)	97	li $t3, ~(0x1f)
98	and $t0, $t0, $t3 # Clear KSU,EXL,ERL,IE	98	and $t0, $t0, $t3 # Clear KSU,EXL,ERL,IE
99		99
100	sw $t2,EOFFSET_STATUS(\r)	100	sw $t2,EOFFSET_STATUS(\r)
101	sw $t1,EOFFSET_EPC(\r)	101	sw $t1,EOFFSET_EPC(\r)
102	mtc0 $t0, $status	102	mtc0 $t0, $status
103	.endm	103	.endm
104		104
105	.macro REGISTERS_LOAD r	105	.macro REGISTERS_LOAD r
106	# Update only UM,EXR,IE from status, the rest	106	# Update only UM,EXR,IE from status, the rest
107	# is controlled by OS and not bound to task	107	# is controlled by OS and not bound to task
108	mfc0 $t0, $status	108	mfc0 $t0, $status
109	lw $t1,EOFFSET_STATUS(\r)	109	lw $t1,EOFFSET_STATUS(\r)
110		110
111	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE	111	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE
112	and $t0, $t0, $t2	112	and $t0, $t0, $t2
113		113
114	or $t0, $t0, $t1 # Copy UM,EXL,ERL,IE from saved status	114	or $t0, $t0, $t1 # Copy UM,EXL,ERL,IE from saved status
115	mtc0 $t0, $status	115	mtc0 $t0, $status
116		116
117	lw $v0,EOFFSET_V0(\r)	117	lw $v0,EOFFSET_V0(\r)
118	lw $v1,EOFFSET_V1(\r)	118	lw $v1,EOFFSET_V1(\r)
119	lw $a0,EOFFSET_A0(\r)	119	lw $a0,EOFFSET_A0(\r)
120	lw $a1,EOFFSET_A1(\r)	120	lw $a1,EOFFSET_A1(\r)
121	lw $a2,EOFFSET_A2(\r)	121	lw $a2,EOFFSET_A2(\r)
122	lw $a3,EOFFSET_A3(\r)	122	lw $a3,EOFFSET_A3(\r)
123	lw $t0,EOFFSET_T0(\r)	123	lw $t0,EOFFSET_T0(\r)
124	lw $t1,EOFFSET_T1(\r)	124	lw $t1,EOFFSET_T1(\r)
125	lw $t2,EOFFSET_T2(\r)	125	lw $t2,EOFFSET_T2(\r)
126	lw $t3,EOFFSET_T3(\r)	126	lw $t3,EOFFSET_T3(\r)
127	lw $t4,EOFFSET_T4(\r)	127	lw $t4,EOFFSET_T4(\r)
128	lw $t5,EOFFSET_T5(\r)	128	lw $t5,EOFFSET_T5(\r)
129	lw $t6,EOFFSET_T6(\r)	129	lw $t6,EOFFSET_T6(\r)
130	lw $t7,EOFFSET_T7(\r)	130	lw $t7,EOFFSET_T7(\r)
131	lw $t8,EOFFSET_T8(\r)	131	lw $t8,EOFFSET_T8(\r)
132	lw $t9,EOFFSET_T9(\r)	132	lw $t9,EOFFSET_T9(\r)
133		133
134	#ifdef CONFIG_DEBUG_ALLREGS	134	#ifdef CONFIG_DEBUG_ALLREGS
135	lw $s0,EOFFSET_S0(\r)	135	lw $s0,EOFFSET_S0(\r)
136	lw $s1,EOFFSET_S1(\r)	136	lw $s1,EOFFSET_S1(\r)
137	lw $s2,EOFFSET_S2(\r)	137	lw $s2,EOFFSET_S2(\r)
138	lw $s3,EOFFSET_S3(\r)	138	lw $s3,EOFFSET_S3(\r)
139	lw $s4,EOFFSET_S4(\r)	139	lw $s4,EOFFSET_S4(\r)
140	lw $s5,EOFFSET_S5(\r)	140	lw $s5,EOFFSET_S5(\r)
141	lw $s6,EOFFSET_S6(\r)	141	lw $s6,EOFFSET_S6(\r)
142	lw $s7,EOFFSET_S7(\r)	142	lw $s7,EOFFSET_S7(\r)
143	lw $s8,EOFFSET_S8(\r)	143	lw $s8,EOFFSET_S8(\r)
144	#endif	144	#endif
145	lw $gp,EOFFSET_GP(\r)	145	lw $gp,EOFFSET_GP(\r)
146	lw $ra,EOFFSET_RA(\r)	146	lw $ra,EOFFSET_RA(\r)
147	lw $k1,EOFFSET_K1(\r)	147	lw $k1,EOFFSET_K1(\r)
148		148
149	lw $at,EOFFSET_LO(\r)	149	lw $at,EOFFSET_LO(\r)
150	mtlo $at	150	mtlo $at
151	lw $at,EOFFSET_HI(\r)	151	lw $at,EOFFSET_HI(\r)
152	mthi $at	152	mthi $at
153		153
154	lw $at,EOFFSET_EPC(\r)	154	lw $at,EOFFSET_EPC(\r)
155	mtc0 $at, $epc	155	mtc0 $at, $epc
156		156
157	lw $at,EOFFSET_AT(\r)	157	lw $at,EOFFSET_AT(\r)
158	lw $sp,EOFFSET_SP(\r)	158	lw $sp,EOFFSET_SP(\r)
159	.endm	159	.endm
160		160
161	# Move kernel stack pointer address to register K0	161	# Move kernel stack pointer address to register K0
162	# - if we are in user mode, load the appropriate stack	162	# - if we are in user mode, load the appropriate stack
163	# address	163	# address
164	.macro KERNEL_STACK_TO_K0	164	.macro KERNEL_STACK_TO_K0
165	# If we are in user mode	165	# If we are in user mode
166	mfc0 $k0, $status	166	mfc0 $k0, $status
167	andi $k0, 0x10	167	andi $k0, 0x10
168		168
169	beq $k0, $0, 1f	169	beq $k0, $0, 1f
170	add $k0, $sp, 0	170	add $k0, $sp, 0
171		171
172	# Move $k0 pointer to kernel stack	172	# Move $k0 pointer to kernel stack
173	lui $k0, %hi(supervisor_sp)	173	lui $k0, %hi(supervisor_sp)
174	ori $k0, $k0, %lo(supervisor_sp)	174	ori $k0, $k0, %lo(supervisor_sp)
175	# Move $k0 (superveisor_sp)	175	# Move $k0 (superveisor_sp)
176	lw $k0, 0($k0)	176	lw $k0, 0($k0)
177	1:	177	1:
178	.endm	178	.endm
179		179
180	.org 0x0	180	.org 0x0
181	kernel_image_start:	181	kernel_image_start:
182	/* Load temporary stack */	182	/* Load temporary stack */
183	lui $sp, %hi(end_stack)	183	lui $sp, %hi(end_stack)
184	ori $sp, $sp, %lo(end_stack)	184	ori $sp, $sp, %lo(end_stack)
185		185
186	/* Not sure about this, but might be needed for PIC code???? */	186	/* Not sure about this, but might be needed for PIC code???? */
187	lui $gp, 0x8000	187	lui $gp, 0x8000
188		188
189	jal arch_pre_main	189	jal arch_pre_main
190	nop	190	nop
191		191
192	j main_bsp	192	j main_bsp
193	nop	193	nop
194		194
195	.space TEMP_STACK_SIZE	195	.space TEMP_STACK_SIZE
196	end_stack:	196	end_stack:
197		197
198	tlb_refill_entry:	198	tlb_refill_entry:
199	j tlb_refill_handler	199	j tlb_refill_handler
200	nop	200	nop
201		201
202	cache_error_entry:	202	cache_error_entry:
203	j cache_error_handler	203	j cache_error_handler
204	nop	204	nop
205		205
206	exception_entry:	206	exception_entry:
207	j exception_handler	207	j exception_handler
208	nop	208	nop
209		209
210		210
211		211
212	exception_handler:	212	exception_handler:
213	KERNEL_STACK_TO_K0	213	KERNEL_STACK_TO_K0
214	sub $k0, REGISTER_SPACE	214	sub $k0, REGISTER_SPACE
215	sw $sp,EOFFSET_SP($k0)	215	sw $sp,EOFFSET_SP($k0)
216	move $sp, $k0	216	move $sp, $k0
217		217
218	mfc0 $k0, $cause	218	mfc0 $k0, $cause
219		219
220	sra $k0, $k0, 0x2 # cp0_exc_cause() part 1	220	sra $k0, $k0, 0x2 # cp0_exc_cause() part 1
221	andi $k0, $k0, 0x1f # cp0_exc_cause() part 2	221	andi $k0, $k0, 0x1f # cp0_exc_cause() part 2
222	sub $k0, 8 # 8=SYSCALL	222	sub $k0, 8 # 8=SYSCALL
223		223
224	beqz $k0, syscall_shortcut	224	beqz $k0, syscall_shortcut
225	add $k0, 8 # Revert $k1 back to correct exc number	225	add $k0, 8 # Revert $k1 back to correct exc number
226		226
227	REGISTERS_STORE_AND_EXC_RESET $sp	227	REGISTERS_STORE_AND_EXC_RESET $sp
228		228
229	move $a1, $sp	229	move $a1, $sp
230	jal exc_dispatch # exc_dispatch(excno, register_space)	230	jal exc_dispatch # exc_dispatch(excno, register_space)
231	move $a0, $k0	231	move $a0, $k0
232		232
233	REGISTERS_LOAD $sp	233	REGISTERS_LOAD $sp
234	# The $sp is automatically restored to former value	234	# The $sp is automatically restored to former value
235	eret	235	eret
236		236
237	# it seems that mips reserves some space on stack for varfuncs???	237	# it seems that mips reserves some space on stack for varfuncs???
238	#define SS_ARG4 16	238	#define SS_ARG4 16
239	#define SS_SP EOFFSET_SP	239	#define SS_SP EOFFSET_SP
240	#define SS_STATUS EOFFSET_STATUS	240	#define SS_STATUS EOFFSET_STATUS
241	#define SS_EPC EOFFSET_EPC	241	#define SS_EPC EOFFSET_EPC
242	syscall_shortcut:	242	syscall_shortcut:
243	# We have a lot of space on the stack, with free use	243	# We have a lot of space on the stack, with free use
244	mfc0 $t1, $epc	244	mfc0 $t1, $epc
245	mfc0 $t0, $status	245	mfc0 $t0, $status
246	sw $t1,SS_EPC($sp) # Save EPC	246	sw $t1,SS_EPC($sp) # Save EPC
247		247
248	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE	248	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
249	li $t3, ~(0x1f)	249	li $t3, ~(0x1f)
250	and $t0, $t0, $t3 # Clear KSU,EXL,ERL	250	and $t0, $t0, $t3 # Clear KSU,EXL,ERL
251	ori $t0, $t0, 0x1 # Set IE	251	ori $t0, $t0, 0x1 # Set IE
252		252
253	sw $t2,SS_STATUS($sp)	253	sw $t2,SS_STATUS($sp)
254	mtc0 $t0, $status	254	mtc0 $t0, $status
255		255
256	li $t4, 2 # SYS_INT_CONTROL	-
257	beq $t4, $v0, sysc_int_control	-
258	nop	-
259		-
260	# CALL Syscall handler	256	# CALL Syscall handler
261	jal syscall_handler	257	jal syscall_handler
262	sw $v0, SS_ARG4($sp) # save v0 - arg4 to stack	258	sw $v0, SS_ARG4($sp) # save v0 - arg4 to stack
263		259
264	sysc_exit:	-
265	# restore status	260	# restore status
266	mfc0 $t0, $status	261	mfc0 $t0, $status
267	lw $t1,SS_STATUS($sp)	262	lw $t1,SS_STATUS($sp)
268		263
269	# Change back to EXL=1(from last exception), otherwise	264	# Change back to EXL=1(from last exception), otherwise
270	# an interrupt could rewrite the CP0-EPC	265	# an interrupt could rewrite the CP0-EPC
271	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE	266	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE
272	and $t0, $t0, $t2	267	and $t0, $t0, $t2
273	or $t0, $t0, $t1 # Copy UM,EXL,ERL,IE from saved status	268	or $t0, $t0, $t1 # Copy UM,EXL,ERL,IE from saved status
274	mtc0 $t0, $status	269	mtc0 $t0, $status
275		270
276	# restore epc+4	271	# restore epc+4
277	lw $t0,SS_EPC($sp)	272	lw $t0,SS_EPC($sp)
278	addi $t0, $t0, 4	273	addi $t0, $t0, 4
279	mtc0 $t0, $epc	274	mtc0 $t0, $epc
280		275
281	lw $sp,SS_SP($sp) # restore sp	276	lw $sp,SS_SP($sp) # restore sp
282		277
283	eret	278	eret
284		279
285	sysc_int_control:	-
286	jal ddi_int_control	-
287	addi $a1, $sp, SS_STATUS	-
288		-
289	j sysc_exit	-
290	nop	-
291		-
292	tlb_refill_handler:	280	tlb_refill_handler:
293	KERNEL_STACK_TO_K0	281	KERNEL_STACK_TO_K0
294	sub $k0, REGISTER_SPACE	282	sub $k0, REGISTER_SPACE
295	REGISTERS_STORE_AND_EXC_RESET $k0	283	REGISTERS_STORE_AND_EXC_RESET $k0
296	sw $sp,EOFFSET_SP($k0)	284	sw $sp,EOFFSET_SP($k0)
297	add $sp, $k0, 0	285	add $sp, $k0, 0
298		286
299	add $a0, $sp, 0	287	add $a0, $sp, 0
300	jal tlb_refill /* tlb_refill(register_space) */	288	jal tlb_refill /* tlb_refill(register_space) */
301	nop	289	nop
302		290
303	REGISTERS_LOAD $sp	291	REGISTERS_LOAD $sp
304		292
305	eret	293	eret
306		294
307	cache_error_handler:	295	cache_error_handler:
308	KERNEL_STACK_TO_K0	296	KERNEL_STACK_TO_K0
309	sub $k0, REGISTER_SPACE	297	sub $k0, REGISTER_SPACE
310	REGISTERS_STORE_AND_EXC_RESET $k0	298	REGISTERS_STORE_AND_EXC_RESET $k0
311	sw $sp,EOFFSET_SP($k0)	299	sw $sp,EOFFSET_SP($k0)
312	add $sp, $k0, 0	300	add $sp, $k0, 0
313		301
314	jal cache_error	302	jal cache_error
315	nop	303	nop
316		304
317	REGISTERS_LOAD $sp	305	REGISTERS_LOAD $sp
318		306
319	eret	307	eret
320		308
321	userspace_asm:	309	userspace_asm:
322	add $sp, $a0, 0	310	add $sp, $a0, 0
323	add $v0, $a1, 0	311	add $v0, $a1, 0
324	add $t9, $a2, 0 # Set up correct entry into PIC code	312	add $t9, $a2, 0 # Set up correct entry into PIC code
325	eret	313	eret
326		314

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/arch/mips32/src/start.S – Rev 1222 → 1278