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308 jermar 1
#
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# Copyright (C) 2003-2004 Jakub Jermar
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# - Redistributions of source code must retain the above copyright
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#   notice, this list of conditions and the following disclaimer.
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# - Redistributions in binary form must reproduce the above copyright
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#   notice, this list of conditions and the following disclaimer in the
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#   documentation and/or other materials provided with the distribution.
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# - The name of the author may not be used to endorse or promote products
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#   derived from this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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306 palkovsky 29
#include <arch/asm/regname.h>
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#include <arch/mm/page.h>
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#include <arch/asm/boot.h>
317 palkovsky 32
#include <arch/context_offset.h>
306 palkovsky 33
 
1 jermar 34
.text
35
 
36
.set noat
37
.set noreorder
38
.set nomacro
39
 
40
.global kernel_image_start
41
.global tlb_refill_entry
42
.global cache_error_entry
43
.global exception_entry
313 palkovsky 44
.global userspace_asm
1 jermar 45
 
1096 palkovsky 46
# Which status bits should are thread-local
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#define REG_SAVE_MASK 0x1f # KSU(UM), EXL, ERL, IE
48
 
313 palkovsky 49
# Save registers to space defined by \r
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# We will change status: Disable ERL,EXL,UM,IE
51
# These changes will be automatically reversed in REGISTER_LOAD
1102 palkovsky 52
# SP is NOT saved as part of these registers
1096 palkovsky 53
.macro REGISTERS_STORE_AND_EXC_RESET r
306 palkovsky 54
	sw $at,EOFFSET_AT(\r)
55
	sw $v0,EOFFSET_V0(\r)
56
	sw $v1,EOFFSET_V1(\r)
57
	sw $a0,EOFFSET_A0(\r)
58
	sw $a1,EOFFSET_A1(\r)
59
	sw $a2,EOFFSET_A2(\r)
60
	sw $a3,EOFFSET_A3(\r)
317 palkovsky 61
	sw $t0,EOFFSET_T0(\r)
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	sw $t1,EOFFSET_T1(\r)
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	sw $t2,EOFFSET_T2(\r)
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	sw $t3,EOFFSET_T3(\r)
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	sw $t4,EOFFSET_T4(\r)
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	sw $t5,EOFFSET_T5(\r)
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	sw $t6,EOFFSET_T6(\r)
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	sw $t7,EOFFSET_T7(\r)
69
	sw $t8,EOFFSET_T8(\r)
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	sw $t9,EOFFSET_T9(\r)
313 palkovsky 71
 
72
	mflo $at
73
	sw $at, EOFFSET_LO(\r)
74
	mfhi $at
75
	sw $at, EOFFSET_HI(\r)
76
 
1094 palkovsky 77
#ifdef CONFIG_DEBUG_ALLREGS	
306 palkovsky 78
	sw $s0,EOFFSET_S0(\r)
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	sw $s1,EOFFSET_S1(\r)
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	sw $s2,EOFFSET_S2(\r)
81
	sw $s3,EOFFSET_S3(\r)
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	sw $s4,EOFFSET_S4(\r)
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	sw $s5,EOFFSET_S5(\r)
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	sw $s6,EOFFSET_S6(\r)
85
	sw $s7,EOFFSET_S7(\r)
1094 palkovsky 86
	sw $s8,EOFFSET_S8(\r)
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#endif
88
 
306 palkovsky 89
	sw $gp,EOFFSET_GP(\r)
90
	sw $ra,EOFFSET_RA(\r)
1102 palkovsky 91
	sw $k1,EOFFSET_K1(\r)
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1096 palkovsky 93
	mfc0 $t0, $status
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	mfc0 $t1, $epc
95
 
96
	and $t2, $t0, REG_SAVE_MASK  # Save only KSU,EXL,ERL,IE
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	li $t3, ~(0x1f)
98
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL,IE
99
 
100
	sw $t2,EOFFSET_STATUS(\r)
101
	sw $t1,EOFFSET_EPC(\r)
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	mtc0 $t0, $status
306 palkovsky 103
.endm
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105
.macro REGISTERS_LOAD r
1096 palkovsky 106
	# Update only UM,EXR,IE from status, the rest
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	# is controlled by OS and not bound to task
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	mfc0 $t0, $status
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	lw $t1,EOFFSET_STATUS(\r)
110
 
111
	li $t2, ~REG_SAVE_MASK    # Mask UM,EXL,ERL,IE
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	and $t0, $t0, $t2
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114
	or $t0, $t0, $t1   # Copy UM,EXL,ERL,IE from saved status
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	mtc0 $t0, $status
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306 palkovsky 117
	lw $v0,EOFFSET_V0(\r)
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	lw $v1,EOFFSET_V1(\r)
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	lw $a0,EOFFSET_A0(\r)
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	lw $a1,EOFFSET_A1(\r)
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	lw $a2,EOFFSET_A2(\r)
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	lw $a3,EOFFSET_A3(\r)
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	lw $t0,EOFFSET_T0(\r)
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	lw $t1,EOFFSET_T1(\r)
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	lw $t2,EOFFSET_T2(\r)
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	lw $t3,EOFFSET_T3(\r)
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	lw $t4,EOFFSET_T4(\r)
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	lw $t5,EOFFSET_T5(\r)
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	lw $t6,EOFFSET_T6(\r)
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	lw $t7,EOFFSET_T7(\r)
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	lw $t8,EOFFSET_T8(\r)
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	lw $t9,EOFFSET_T9(\r)
1094 palkovsky 133
 
134
#ifdef CONFIG_DEBUG_ALLREGS	
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	lw $s0,EOFFSET_S0(\r)
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	lw $s1,EOFFSET_S1(\r)
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	lw $s2,EOFFSET_S2(\r)
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	lw $s3,EOFFSET_S3(\r)
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	lw $s4,EOFFSET_S4(\r)
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	lw $s5,EOFFSET_S5(\r)
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	lw $s6,EOFFSET_S6(\r)
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	lw $s7,EOFFSET_S7(\r)
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	lw $s8,EOFFSET_S8(\r)
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#endif
306 palkovsky 145
	lw $gp,EOFFSET_GP(\r)
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	lw $ra,EOFFSET_RA(\r)
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	lw $k1,EOFFSET_K1(\r)
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313 palkovsky 149
	lw $at,EOFFSET_LO(\r)
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	mtlo $at
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	lw $at,EOFFSET_HI(\r)
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	mthi $at
153
 
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	lw $at,EOFFSET_EPC(\r)
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	mtc0 $at, $epc
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157
	lw $at,EOFFSET_AT(\r)
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	lw $sp,EOFFSET_SP(\r)
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.endm
160
 
313 palkovsky 161
# Move kernel stack pointer address to register K0
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# - if we are in user mode, load the appropriate stack
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# address
164
.macro KERNEL_STACK_TO_K0
165
	# If we are in user mode
166
	mfc0 $k0, $status
167
	andi $k0, 0x10
306 palkovsky 168
 
313 palkovsky 169
	beq $k0, $0, 1f
170
	add $k0, $sp, 0
171
 
172
	# Move $k0 pointer to kernel stack
173
	lui $k0, %hi(supervisor_sp)
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	ori $k0, $k0, %lo(supervisor_sp)
313 palkovsky 175
	# Move $k0 (superveisor_sp)
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	lw $k0, 0($k0)
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1:		
178
.endm
179
 
1 jermar 180
.org 0x0
306 palkovsky 181
kernel_image_start:
182
	/* Load temporary stack */
313 palkovsky 183
	lui $sp, %hi(end_stack)
320 palkovsky 184
	ori $sp, $sp, %lo(end_stack)
1686 decky 185
 
186
	/* $a1 contains physical address of bootinfo_t */
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	/* $a2 contains size of bootinfo_t */
188
 
189
	beq $a2, $0, bootinfo_end
190
 
306 palkovsky 191
	/* Not sure about this, but might be needed for PIC code???? */
192
	lui $gp, 0x8000
193
 
1686 decky 194
	lui $a3, %hi(bootinfo)
195
	ori $a3, $a3, %lo(bootinfo)
196
 
197
	bootinfo_loop:
198
 
199
		lw $v0, 0($a1)
200
		sw $v0, 0($a3)
201
 
202
		addi $a1, $a1, 4
203
		addi $a3, $a3, 4
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		addi $a2, $a2, -4
205
 
206
		bgtz $a2, bootinfo_loop
207
		nop
208
 
209
	bootinfo_end:
210
 
1222 decky 211
	jal arch_pre_main
306 palkovsky 212
	nop
1222 decky 213
 
214
	j main_bsp
215
	nop
306 palkovsky 216
 
217
	.space TEMP_STACK_SIZE
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end_stack:
219
 
220
tlb_refill_entry:
221
	j tlb_refill_handler
222
	nop
223
 
224
cache_error_entry:
225
	j cache_error_handler
226
	nop
227
 
228
exception_entry:
229
	j exception_handler
230
	nop	
231
 
306 palkovsky 232
 
326 palkovsky 233
 
313 palkovsky 234
exception_handler:
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	KERNEL_STACK_TO_K0
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	sub $k0, REGISTER_SPACE
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	sw $sp,EOFFSET_SP($k0)
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	move $sp, $k0
1096 palkovsky 239
 
1102 palkovsky 240
	mfc0 $k0, $cause
1096 palkovsky 241
 
1102 palkovsky 242
	sra $k0, $k0, 0x2     # cp0_exc_cause() part 1
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	andi $k0, $k0, 0x1f   # cp0_exc_cause() part 2
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	sub $k0, 8            # 8=SYSCALL
1096 palkovsky 245
 
1102 palkovsky 246
	beqz $k0, syscall_shortcut
1386 palkovsky 247
	add $k0, 8            # Revert $k0 back to correct exc number
1096 palkovsky 248
 
1102 palkovsky 249
	REGISTERS_STORE_AND_EXC_RESET $sp
250
 
1096 palkovsky 251
	move $a1, $sp
252
	jal exc_dispatch      # exc_dispatch(excno, register_space)
1102 palkovsky 253
	move $a0, $k0
313 palkovsky 254
 
255
	REGISTERS_LOAD $sp
256
	# The $sp is automatically restored to former value
257
	eret
1096 palkovsky 258
 
259
# it seems that mips reserves some space on stack for varfuncs???
260
#define SS_ARG4   16
1102 palkovsky 261
#define SS_SP     EOFFSET_SP
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#define SS_STATUS EOFFSET_STATUS
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#define SS_EPC    EOFFSET_EPC
1386 palkovsky 264
#define SS_K1     EOFFSET_K1
1100 palkovsky 265
syscall_shortcut:
1096 palkovsky 266
	# We have a lot of space on the stack, with free use
267
	mfc0 $t1, $epc
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	mfc0 $t0, $status
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	sw $t1,SS_EPC($sp)  # Save EPC
1386 palkovsky 270
	sw $k1,SS_K1($sp)   # Save k1, which is not saved during context switch
313 palkovsky 271
 
1096 palkovsky 272
	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
273
	li $t3, ~(0x1f)
274
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL
275
	ori $t0, $t0, 0x1           # Set IE
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277
	sw $t2,SS_STATUS($sp)
278
	mtc0 $t0, $status
279
 
1126 palkovsky 280
	# CALL Syscall handler
1096 palkovsky 281
	jal syscall_handler
282
	sw $v0, SS_ARG4($sp)        # save v0 - arg4 to stack
283
 
284
	# restore status
285
	mfc0 $t0, $status
286
	lw $t1,SS_STATUS($sp)
287
 
1126 palkovsky 288
	# Change back to EXL=1(from last exception), otherwise
289
	# an interrupt could rewrite the CP0-EPC
1096 palkovsky 290
	li $t2, ~REG_SAVE_MASK      # Mask UM,EXL,ERL,IE
291
	and $t0, $t0, $t2
292
	or $t0, $t0, $t1            # Copy UM,EXL,ERL,IE from saved status
293
	mtc0 $t0, $status
294
 
1126 palkovsky 295
	# restore epc+4
296
	lw $t0,SS_EPC($sp)
1386 palkovsky 297
	lw $k1,SS_K1($sp)
1126 palkovsky 298
	addi $t0, $t0, 4
299
	mtc0 $t0, $epc
300
 
1096 palkovsky 301
	lw $sp,SS_SP($sp) # restore sp
302
 
303
	eret
1278 palkovsky 304
 
1 jermar 305
tlb_refill_handler:
313 palkovsky 306
	KERNEL_STACK_TO_K0
307
	sub $k0, REGISTER_SPACE
1096 palkovsky 308
	REGISTERS_STORE_AND_EXC_RESET $k0
1102 palkovsky 309
	sw $sp,EOFFSET_SP($k0)
313 palkovsky 310
	add $sp, $k0, 0
125 jermar 311
 
1769 jermar 312
	jal tlb_refill
317 palkovsky 313
	add $a0, $sp, 0 
125 jermar 314
 
306 palkovsky 315
	REGISTERS_LOAD $sp
125 jermar 316
 
50 jermar 317
	eret
1 jermar 318
 
319
cache_error_handler:
313 palkovsky 320
	KERNEL_STACK_TO_K0
1102 palkovsky 321
	sub $k0, REGISTER_SPACE
322
	REGISTERS_STORE_AND_EXC_RESET $k0
323
	sw $sp,EOFFSET_SP($k0)
313 palkovsky 324
	add $sp, $k0, 0
1 jermar 325
 
50 jermar 326
	jal cache_error
1769 jermar 327
	add $a0, $sp, 0 
125 jermar 328
 
306 palkovsky 329
	REGISTERS_LOAD $sp
1 jermar 330
 
50 jermar 331
	eret
313 palkovsky 332
 
333
userspace_asm:
334
	add $sp, $a0, 0
1122 palkovsky 335
	add $v0, $a1, 0 
336
	add $t9, $a2, 0   # Set up correct entry into PIC code 
313 palkovsky 337
	eret