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 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
 
	jal syscall_handler
	sw $v0, SS_ARG4($sp)        # save v0 - arg4 to stack
 
	# restore epc+4
	lw $t0,SS_EPC($sp)
	addi $t0, $t0, 4
	mtc0 $t0, $epc
	
	# restore status
	mfc0 $t0, $status
	lw $t1,SS_STATUS($sp)
 
	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 $sp,SS_SP($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
	eret
 
 

Rev 1100	Rev 1102
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	.macro REGISTERS_STORE_AND_EXC_RESET r	53	.macro REGISTERS_STORE_AND_EXC_RESET r
53	sw $at,EOFFSET_AT(\r)	54	sw $at,EOFFSET_AT(\r)
54	sw $v0,EOFFSET_V0(\r)	55	sw $v0,EOFFSET_V0(\r)
55	sw $v1,EOFFSET_V1(\r)	56	sw $v1,EOFFSET_V1(\r)
56	sw $a0,EOFFSET_A0(\r)	57	sw $a0,EOFFSET_A0(\r)
57	sw $a1,EOFFSET_A1(\r)	58	sw $a1,EOFFSET_A1(\r)
58	sw $a2,EOFFSET_A2(\r)	59	sw $a2,EOFFSET_A2(\r)
59	sw $a3,EOFFSET_A3(\r)	60	sw $a3,EOFFSET_A3(\r)
60	sw $t0,EOFFSET_T0(\r)	61	sw $t0,EOFFSET_T0(\r)
61	sw $t1,EOFFSET_T1(\r)	62	sw $t1,EOFFSET_T1(\r)
62	sw $t2,EOFFSET_T2(\r)	63	sw $t2,EOFFSET_T2(\r)
63	sw $t3,EOFFSET_T3(\r)	64	sw $t3,EOFFSET_T3(\r)
64	sw $t4,EOFFSET_T4(\r)	65	sw $t4,EOFFSET_T4(\r)
65	sw $t5,EOFFSET_T5(\r)	66	sw $t5,EOFFSET_T5(\r)
66	sw $t6,EOFFSET_T6(\r)	67	sw $t6,EOFFSET_T6(\r)
67	sw $t7,EOFFSET_T7(\r)	68	sw $t7,EOFFSET_T7(\r)
68	sw $t8,EOFFSET_T8(\r)	69	sw $t8,EOFFSET_T8(\r)
69	sw $t9,EOFFSET_T9(\r)	70	sw $t9,EOFFSET_T9(\r)
70		71
71	mflo $at	72	mflo $at
72	sw $at, EOFFSET_LO(\r)	73	sw $at, EOFFSET_LO(\r)
73	mfhi $at	74	mfhi $at
74	sw $at, EOFFSET_HI(\r)	75	sw $at, EOFFSET_HI(\r)
75		76
76	#ifdef CONFIG_DEBUG_ALLREGS	77	#ifdef CONFIG_DEBUG_ALLREGS
77	sw $s0,EOFFSET_S0(\r)	78	sw $s0,EOFFSET_S0(\r)
78	sw $s1,EOFFSET_S1(\r)	79	sw $s1,EOFFSET_S1(\r)
79	sw $s2,EOFFSET_S2(\r)	80	sw $s2,EOFFSET_S2(\r)
80	sw $s3,EOFFSET_S3(\r)	81	sw $s3,EOFFSET_S3(\r)
81	sw $s4,EOFFSET_S4(\r)	82	sw $s4,EOFFSET_S4(\r)
82	sw $s5,EOFFSET_S5(\r)	83	sw $s5,EOFFSET_S5(\r)
83	sw $s6,EOFFSET_S6(\r)	84	sw $s6,EOFFSET_S6(\r)
84	sw $s7,EOFFSET_S7(\r)	85	sw $s7,EOFFSET_S7(\r)
85	sw $s8,EOFFSET_S8(\r)	86	sw $s8,EOFFSET_S8(\r)
86	#endif	87	#endif
87		88
88	sw $gp,EOFFSET_GP(\r)	89	sw $gp,EOFFSET_GP(\r)
89	sw $ra,EOFFSET_RA(\r)	90	sw $ra,EOFFSET_RA(\r)
90	sw $sp,EOFFSET_SP(\r)	91	sw $k1,EOFFSET_K1(\r)
91		92
92	mfc0 $t0, $status	93	mfc0 $t0, $status
93	mfc0 $t1, $epc	94	mfc0 $t1, $epc
94		95
95	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
96	li $t3, ~(0x1f)	97	li $t3, ~(0x1f)
97	and $t0, $t0, $t3 # Clear KSU,EXL,ERL,IE	98	and $t0, $t0, $t3 # Clear KSU,EXL,ERL,IE
98		99
99	sw $t2,EOFFSET_STATUS(\r)	100	sw $t2,EOFFSET_STATUS(\r)
100	sw $t1,EOFFSET_EPC(\r)	101	sw $t1,EOFFSET_EPC(\r)
101	mtc0 $t0, $status	102	mtc0 $t0, $status
102	.endm	103	.endm
103		104
104	.macro REGISTERS_LOAD r	105	.macro REGISTERS_LOAD r
105	# Update only UM,EXR,IE from status, the rest	106	# Update only UM,EXR,IE from status, the rest
106	# is controlled by OS and not bound to task	107	# is controlled by OS and not bound to task
107	mfc0 $t0, $status	108	mfc0 $t0, $status
108	lw $t1,EOFFSET_STATUS(\r)	109	lw $t1,EOFFSET_STATUS(\r)
109		110
110	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE	111	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE
111	and $t0, $t0, $t2	112	and $t0, $t0, $t2
112		113
113	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
114	mtc0 $t0, $status	115	mtc0 $t0, $status
115		116
116	lw $v0,EOFFSET_V0(\r)	117	lw $v0,EOFFSET_V0(\r)
117	lw $v1,EOFFSET_V1(\r)	118	lw $v1,EOFFSET_V1(\r)
118	lw $a0,EOFFSET_A0(\r)	119	lw $a0,EOFFSET_A0(\r)
119	lw $a1,EOFFSET_A1(\r)	120	lw $a1,EOFFSET_A1(\r)
120	lw $a2,EOFFSET_A2(\r)	121	lw $a2,EOFFSET_A2(\r)
121	lw $a3,EOFFSET_A3(\r)	122	lw $a3,EOFFSET_A3(\r)
122	lw $t0,EOFFSET_T0(\r)	123	lw $t0,EOFFSET_T0(\r)
123	lw $t1,EOFFSET_T1(\r)	124	lw $t1,EOFFSET_T1(\r)
124	lw $t2,EOFFSET_T2(\r)	125	lw $t2,EOFFSET_T2(\r)
125	lw $t3,EOFFSET_T3(\r)	126	lw $t3,EOFFSET_T3(\r)
126	lw $t4,EOFFSET_T4(\r)	127	lw $t4,EOFFSET_T4(\r)
127	lw $t5,EOFFSET_T5(\r)	128	lw $t5,EOFFSET_T5(\r)
128	lw $t6,EOFFSET_T6(\r)	129	lw $t6,EOFFSET_T6(\r)
129	lw $t7,EOFFSET_T7(\r)	130	lw $t7,EOFFSET_T7(\r)
130	lw $t8,EOFFSET_T8(\r)	131	lw $t8,EOFFSET_T8(\r)
131	lw $t9,EOFFSET_T9(\r)	132	lw $t9,EOFFSET_T9(\r)
132		133
133	#ifdef CONFIG_DEBUG_ALLREGS	134	#ifdef CONFIG_DEBUG_ALLREGS
134	lw $s0,EOFFSET_S0(\r)	135	lw $s0,EOFFSET_S0(\r)
135	lw $s1,EOFFSET_S1(\r)	136	lw $s1,EOFFSET_S1(\r)
136	lw $s2,EOFFSET_S2(\r)	137	lw $s2,EOFFSET_S2(\r)
137	lw $s3,EOFFSET_S3(\r)	138	lw $s3,EOFFSET_S3(\r)
138	lw $s4,EOFFSET_S4(\r)	139	lw $s4,EOFFSET_S4(\r)
139	lw $s5,EOFFSET_S5(\r)	140	lw $s5,EOFFSET_S5(\r)
140	lw $s6,EOFFSET_S6(\r)	141	lw $s6,EOFFSET_S6(\r)
141	lw $s7,EOFFSET_S7(\r)	142	lw $s7,EOFFSET_S7(\r)
142	lw $s8,EOFFSET_S8(\r)	143	lw $s8,EOFFSET_S8(\r)
143	#endif	144	#endif
144	lw $gp,EOFFSET_GP(\r)	145	lw $gp,EOFFSET_GP(\r)
145	lw $ra,EOFFSET_RA(\r)	146	lw $ra,EOFFSET_RA(\r)
-		147	lw $k1,EOFFSET_K1(\r)
146		148
147	lw $at,EOFFSET_LO(\r)	149	lw $at,EOFFSET_LO(\r)
148	mtlo $at	150	mtlo $at
149	lw $at,EOFFSET_HI(\r)	151	lw $at,EOFFSET_HI(\r)
150	mthi $at	152	mthi $at
151		153
152	lw $at,EOFFSET_EPC(\r)	154	lw $at,EOFFSET_EPC(\r)
153	mtc0 $at, $epc	155	mtc0 $at, $epc
154		156
155	lw $at,EOFFSET_AT(\r)	157	lw $at,EOFFSET_AT(\r)
156	lw $sp,EOFFSET_SP(\r)	158	lw $sp,EOFFSET_SP(\r)
157	.endm	159	.endm
158		160
159	# Move kernel stack pointer address to register K0	161	# Move kernel stack pointer address to register K0
160	# - if we are in user mode, load the appropriate stack	162	# - if we are in user mode, load the appropriate stack
161	# address	163	# address
162	.macro KERNEL_STACK_TO_K0	164	.macro KERNEL_STACK_TO_K0
163	# If we are in user mode	165	# If we are in user mode
164	mfc0 $k0, $status	166	mfc0 $k0, $status
165	andi $k0, 0x10	167	andi $k0, 0x10
166		168
167	beq $k0, $0, 1f	169	beq $k0, $0, 1f
168	add $k0, $sp, 0	170	add $k0, $sp, 0
169		171
170	# Move $k0 pointer to kernel stack	172	# Move $k0 pointer to kernel stack
171	lui $k0, %hi(supervisor_sp)	173	lui $k0, %hi(supervisor_sp)
172	ori $k0, $k0, %lo(supervisor_sp)	174	ori $k0, $k0, %lo(supervisor_sp)
173	# Move $k0 (superveisor_sp)	175	# Move $k0 (superveisor_sp)
174	lw $k0, 0($k0)	176	lw $k0, 0($k0)
175	1:	177	1:
176	.endm	178	.endm
177		179
178	.org 0x0	180	.org 0x0
179	kernel_image_start:	181	kernel_image_start:
180	/* Load temporary stack */	182	/* Load temporary stack */
181	lui $sp, %hi(end_stack)	183	lui $sp, %hi(end_stack)
182	ori $sp, $sp, %lo(end_stack)	184	ori $sp, $sp, %lo(end_stack)
183		185
184	/* Not sure about this, but might be needed for PIC code???? */	186	/* Not sure about this, but might be needed for PIC code???? */
185	lui $gp, 0x8000	187	lui $gp, 0x8000
186		188
187	jal main_bsp	189	jal main_bsp
188	nop	190	nop
189		191
190		192
191	.space TEMP_STACK_SIZE	193	.space TEMP_STACK_SIZE
192	end_stack:	194	end_stack:
193		195
194	tlb_refill_entry:	196	tlb_refill_entry:
195	j tlb_refill_handler	197	j tlb_refill_handler
196	nop	198	nop
197		199
198	cache_error_entry:	200	cache_error_entry:
199	j cache_error_handler	201	j cache_error_handler
200	nop	202	nop
201		203
202	exception_entry:	204	exception_entry:
203	j exception_handler	205	j exception_handler
204	nop	206	nop
205		207
206		208
207		209
208	exception_handler:	210	exception_handler:
209	KERNEL_STACK_TO_K0	211	KERNEL_STACK_TO_K0
210		-
211	mfc0 $k1, $cause	-
212	sub $k0, REGISTER_SPACE	212	sub $k0, REGISTER_SPACE
-		213	sw $sp,EOFFSET_SP($k0)
-		214	move $sp, $k0
213		215
214	sra $k1, $k1, 0x2 # cp0_exc_cause() part 1	-
215	andi $k1, $k1, 0x1f # cp0_exc_cause() part 2	216	mfc0 $k0, $cause
216	sub $k1, 8 # 8=SYSCALL	-
217		217
218	beqz $k1, syscall_shortcut	218	sra $k0, $k0, 0x2 # cp0_exc_cause() part 1
219	add $k1, 8 # Revert $k1 back to correct exc number	219	andi $k0, $k0, 0x1f # cp0_exc_cause() part 2
-		220	sub $k0, 8 # 8=SYSCALL
220		221
-		222	beqz $k0, syscall_shortcut
-		223	add $k0, 8 # Revert $k1 back to correct exc number
-		224
221	REGISTERS_STORE_AND_EXC_RESET $k0	225	REGISTERS_STORE_AND_EXC_RESET $sp
222	move $sp, $k0	-
223		226
224	move $a1, $sp	227	move $a1, $sp
225	jal exc_dispatch # exc_dispatch(excno, register_space)	228	jal exc_dispatch # exc_dispatch(excno, register_space)
226	move $a0, $k1	229	move $a0, $k0
227		230
228	REGISTERS_LOAD $sp	231	REGISTERS_LOAD $sp
229	# The $sp is automatically restored to former value	232	# The $sp is automatically restored to former value
230	eret	233	eret
231		234
232	# it seems that mips reserves some space on stack for varfuncs???	235	# it seems that mips reserves some space on stack for varfuncs???
233	#define SS_ARG4 16	236	#define SS_ARG4 16
234	#define SS_SP 20	237	#define SS_SP EOFFSET_SP
235	#define SS_STATUS 24	238	#define SS_STATUS EOFFSET_STATUS
236	#define SS_EPC 28	239	#define SS_EPC EOFFSET_EPC
237	syscall_shortcut:	240	syscall_shortcut:
238	# We have a lot of space on the stack, with free use	241	# We have a lot of space on the stack, with free use
239	sw $sp, SS_SP($k0)	-
240	move $sp, $k0	-
241		-
242	mfc0 $t1, $epc	242	mfc0 $t1, $epc
243	mfc0 $t0, $status	243	mfc0 $t0, $status
244	sw $t1,SS_EPC($sp) # Save EPC	244	sw $t1,SS_EPC($sp) # Save EPC
245		245
246	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE	246	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
247	li $t3, ~(0x1f)	247	li $t3, ~(0x1f)
248	and $t0, $t0, $t3 # Clear KSU,EXL,ERL	248	and $t0, $t0, $t3 # Clear KSU,EXL,ERL
249	ori $t0, $t0, 0x1 # Set IE	249	ori $t0, $t0, 0x1 # Set IE
250		250
251	sw $t2,SS_STATUS($sp)	251	sw $t2,SS_STATUS($sp)
252	mtc0 $t0, $status	252	mtc0 $t0, $status
253		253
254	jal syscall_handler	254	jal syscall_handler
255	sw $v0, SS_ARG4($sp) # save v0 - arg4 to stack	255	sw $v0, SS_ARG4($sp) # save v0 - arg4 to stack
256		256
257	# restore epc+4	257	# restore epc+4
258	lw $t0,SS_EPC($sp)	258	lw $t0,SS_EPC($sp)
259	addi $t0, $t0, 4	259	addi $t0, $t0, 4
260	mtc0 $t0, $epc	260	mtc0 $t0, $epc
261		261
262	# restore status	262	# restore status
263	mfc0 $t0, $status	263	mfc0 $t0, $status
264	lw $t1,SS_STATUS($sp)	264	lw $t1,SS_STATUS($sp)
265		265
266	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE	266	li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE
267	and $t0, $t0, $t2	267	and $t0, $t0, $t2
268	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
269	mtc0 $t0, $status	269	mtc0 $t0, $status
270		270
271	lw $sp,SS_SP($sp) # restore sp	271	lw $sp,SS_SP($sp) # restore sp
272		272
273	eret	273	eret
274		274
275	tlb_refill_handler:	275	tlb_refill_handler:
276	KERNEL_STACK_TO_K0	276	KERNEL_STACK_TO_K0
277	sub $k0, REGISTER_SPACE	277	sub $k0, REGISTER_SPACE
278	REGISTERS_STORE_AND_EXC_RESET $k0	278	REGISTERS_STORE_AND_EXC_RESET $k0
-		279	sw $sp,EOFFSET_SP($k0)
279	add $sp, $k0, 0	280	add $sp, $k0, 0
280		281
281	add $a0, $sp, 0	282	add $a0, $sp, 0
282	jal tlb_refill /* tlb_refill(register_space) */	283	jal tlb_refill /* tlb_refill(register_space) */
283	nop	284	nop
284		285
285	REGISTERS_LOAD $sp	286	REGISTERS_LOAD $sp
286		287
287	eret	288	eret
288		289
289	cache_error_handler:	290	cache_error_handler:
290	KERNEL_STACK_TO_K0	291	KERNEL_STACK_TO_K0
291	sub $sp, REGISTER_SPACE	292	sub $k0, REGISTER_SPACE
292	REGISTERS_STORE_AND_EXC_RESET $sp	293	REGISTERS_STORE_AND_EXC_RESET $k0
-		294	sw $sp,EOFFSET_SP($k0)
293	add $sp, $k0, 0	295	add $sp, $k0, 0
294		296
295	jal cache_error	297	jal cache_error
296	nop	298	nop
297		299
298	REGISTERS_LOAD $sp	300	REGISTERS_LOAD $sp
299		301
300	eret	302	eret
301		303
302	userspace_asm:	304	userspace_asm:
303	add $sp, $a0, 0	305	add $sp, $a0, 0
304	add $v0, $a1, 0	306	add $v0, $a1, 0
305	eret	307	eret
306		308
307		309

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(root)/kernel/trunk/arch/mips32/src/start.S – Rev 1100 → 1102