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| Rev 2071 | Rev 2607 | ||
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| 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 | #include <arch/stack.h> |
|
| 33 | 34 | ||
| 34 | .text |
35 | .text |
| 35 | 36 | ||
| 36 | .set noat |
37 | .set noat |
| 37 | .set noreorder |
38 | .set noreorder |
| Line 227... | Line 228... | ||
| 227 | 228 | ||
| 228 | exception_entry: |
229 | exception_entry: |
| 229 | j exception_handler |
230 | j exception_handler |
| 230 | nop |
231 | nop |
| 231 | 232 | ||
| 232 | - | ||
| 233 | - | ||
| 234 | exception_handler: |
233 | exception_handler: |
| 235 | KERNEL_STACK_TO_K0 |
234 | KERNEL_STACK_TO_K0 |
| 236 | sub $k0, REGISTER_SPACE |
235 | sub $k0, REGISTER_SPACE |
| 237 | sw $sp,EOFFSET_SP($k0) |
236 | sw $sp, EOFFSET_SP($k0) |
| 238 | move $sp, $k0 |
237 | move $sp, $k0 |
| Line 254... | Line 253... | ||
| 254 | 253 | ||
| 255 | REGISTERS_LOAD $sp |
254 | REGISTERS_LOAD $sp |
| 256 | # The $sp is automatically restored to former value |
255 | # The $sp is automatically restored to former value |
| 257 | eret |
256 | eret |
| 258 | 257 | ||
| - | 258 | ## Syscall entry |
|
| - | 259 | # |
|
| - | 260 | # Registers: |
|
| - | 261 | # |
|
| - | 262 | # @param v0 Syscall number. |
|
| 259 | # it seems that mips reserves some space on stack for varfuncs??? |
263 | # @param a0 1st argument. |
| 260 | #define SS_ARG4 16 |
264 | # @param a1 2nd argument. |
| - | 265 | # @param a2 3rd argument. |
|
| - | 266 | # @param a3 4th argument. |
|
| - | 267 | # @param t0 5th argument. |
|
| - | 268 | # @param t1 6th argument. |
|
| - | 269 | # |
|
| - | 270 | # @return The return value will be stored in v0. |
|
| - | 271 | # |
|
| 261 | #define SS_SP EOFFSET_SP |
272 | #define SS_SP EOFFSET_SP |
| 262 | #define SS_STATUS EOFFSET_STATUS |
273 | #define SS_STATUS EOFFSET_STATUS |
| 263 | #define SS_EPC EOFFSET_EPC |
274 | #define SS_EPC EOFFSET_EPC |
| 264 | #define SS_K1 EOFFSET_K1 |
275 | #define SS_K1 EOFFSET_K1 |
| 265 | syscall_shortcut: |
276 | syscall_shortcut: |
| 266 | # We have a lot of space on the stack, with free use |
277 | # We have a lot of space on the stack, with free use |
| 267 | mfc0 $t1, $epc |
278 | mfc0 $t3, $epc |
| 268 | mfc0 $t0, $status |
279 | mfc0 $t2, $status |
| 269 | sw $t1,SS_EPC($sp) # Save EPC |
280 | sw $t3, SS_EPC($sp) # Save EPC |
| 270 | sw $k1,SS_K1($sp) # Save k1, which is not saved during context switch |
281 | sw $k1, SS_K1($sp) # Save k1 not saved on context switch |
| 271 | 282 | ||
| 272 | and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE |
283 | and $t4, $t2, REG_SAVE_MASK # Save only KSU, EXL, ERL, IE |
| 273 | li $t3, ~(0x1f) |
284 | li $t5, ~(0x1f) |
| 274 | and $t0, $t0, $t3 # Clear KSU,EXL,ERL |
285 | and $t2, $t2, $t5 # Clear KSU, EXL, ERL |
| 275 | ori $t0, $t0, 0x1 # Set IE |
286 | ori $t2, $t2, 0x1 # Set IE |
| 276 | 287 | ||
| 277 | sw $t2,SS_STATUS($sp) |
288 | sw $t4, SS_STATUS($sp) |
| 278 | mtc0 $t0, $status |
289 | mtc0 $t2, $status |
| 279 | 290 | ||
| - | 291 | # |
|
| 280 | # CALL Syscall handler |
292 | # Call the higher level system call handler |
| - | 293 | # We are going to reuse part of the unused exception stack frame |
|
| - | 294 | # |
|
| - | 295 | sw $t0, STACK_ARG4($sp) # save the 5th argument on the stack |
|
| - | 296 | sw $t1, STACK_ARG5($sp) # save the 6th argument on the stack |
|
| 281 | jal syscall_handler |
297 | jal syscall_handler |
| 282 | sw $v0, SS_ARG4($sp) # save v0 - arg4 to stack |
298 | sw $v0, STACK_ARG6($sp) # save the syscall number on the stack |
| 283 | 299 | ||
| 284 | # restore status |
300 | # restore status |
| 285 | mfc0 $t0, $status |
301 | mfc0 $t2, $status |
| 286 | lw $t1,SS_STATUS($sp) |
302 | lw $t3, SS_STATUS($sp) |
| 287 | 303 | ||
| 288 | # Change back to EXL=1(from last exception), otherwise |
304 | # Change back to EXL = 1 (from last exception), otherwise |
| 289 | # an interrupt could rewrite the CP0-EPC |
305 | # an interrupt could rewrite the CP0 - EPC |
| 290 | li $t2, ~REG_SAVE_MASK # Mask UM,EXL,ERL,IE |
306 | li $t4, ~REG_SAVE_MASK # Mask UM, EXL, ERL, IE |
| 291 | and $t0, $t0, $t2 |
307 | and $t2, $t2, $t4 |
| 292 | or $t0, $t0, $t1 # Copy UM,EXL,ERL,IE from saved status |
308 | or $t2, $t2, $t3 # Copy saved UM, EXL, ERL, IE |
| 293 | mtc0 $t0, $status |
309 | mtc0 $t2, $status |
| 294 | 310 | ||
| 295 | # restore epc+4 |
311 | # restore epc + 4 |
| 296 | lw $t0,SS_EPC($sp) |
312 | lw $t2, SS_EPC($sp) |
| 297 | lw $k1,SS_K1($sp) |
313 | lw $k1, SS_K1($sp) |
| 298 | addi $t0, $t0, 4 |
314 | addi $t2, $t2, 4 |
| 299 | mtc0 $t0, $epc |
315 | mtc0 $t2, $epc |
| 300 | 316 | ||
| 301 | lw $sp,SS_SP($sp) # restore sp |
317 | lw $sp, SS_SP($sp) # restore sp |
| 302 | 318 | ||
| 303 | eret |
319 | eret |
| 304 | 320 | ||