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