| blob | ef548510b951b306d7b70cb941d08dc0dec3e4dd |
1 /*
2 * Low-level system-call handling, trap handlers and context-switching
3 *
4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2008-2009 PetaLogix
6 * Copyright (C) 2003 John Williams <jwilliams@itee.uq.edu.au>
7 * Copyright (C) 2001,2002 NEC Corporation
8 * Copyright (C) 2001,2002 Miles Bader <miles@gnu.org>
9 *
10 * This file is subject to the terms and conditions of the GNU General
11 * Public License. See the file COPYING in the main directory of this
12 * archive for more details.
13 *
14 * Written by Miles Bader <miles@gnu.org>
15 * Heavily modified by John Williams for Microblaze
16 */
18 #include <linux/sys.h>
19 #include <linux/linkage.h>
21 #include <asm/entry.h>
22 #include <asm/current.h>
23 #include <asm/processor.h>
24 #include <asm/exceptions.h>
25 #include <asm/asm-offsets.h>
26 #include <asm/thread_info.h>
28 #include <asm/page.h>
29 #include <asm/unistd.h>
31 #include <linux/errno.h>
32 #include <asm/signal.h>
34 #undef DEBUG
36 #ifdef DEBUG
37 /* Create space for syscalls counting. */
38 .section .data
39 .global syscall_debug_table
40 .align 4
41 syscall_debug_table:
42 .space (__NR_syscalls * 4)
43 #endif /* DEBUG */
45 #define C_ENTRY(name) .globl name; .align 4; name
47 /*
48 * Various ways of setting and clearing BIP in flags reg.
49 * This is mucky, but necessary using microblaze version that
50 * allows msr ops to write to BIP
51 */
52 #if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR
53 .macro clear_bip
54 msrclr r0, MSR_BIP
55 .endm
57 .macro set_bip
58 msrset r0, MSR_BIP
59 .endm
61 .macro clear_eip
62 msrclr r0, MSR_EIP
63 .endm
65 .macro set_ee
66 msrset r0, MSR_EE
67 .endm
69 .macro disable_irq
70 msrclr r0, MSR_IE
71 .endm
73 .macro enable_irq
74 msrset r0, MSR_IE
75 .endm
77 .macro set_ums
78 msrset r0, MSR_UMS
79 msrclr r0, MSR_VMS
80 .endm
82 .macro set_vms
83 msrclr r0, MSR_UMS
84 msrset r0, MSR_VMS
85 .endm
87 .macro clear_ums
88 msrclr r0, MSR_UMS
89 .endm
91 .macro clear_vms_ums
92 msrclr r0, MSR_VMS | MSR_UMS
93 .endm
94 #else
95 .macro clear_bip
96 mfs r11, rmsr
97 andi r11, r11, ~MSR_BIP
98 mts rmsr, r11
99 .endm
101 .macro set_bip
102 mfs r11, rmsr
103 ori r11, r11, MSR_BIP
104 mts rmsr, r11
105 .endm
107 .macro clear_eip
108 mfs r11, rmsr
109 andi r11, r11, ~MSR_EIP
110 mts rmsr, r11
111 .endm
113 .macro set_ee
114 mfs r11, rmsr
115 ori r11, r11, MSR_EE
116 mts rmsr, r11
117 .endm
119 .macro disable_irq
120 mfs r11, rmsr
121 andi r11, r11, ~MSR_IE
122 mts rmsr, r11
123 .endm
125 .macro enable_irq
126 mfs r11, rmsr
127 ori r11, r11, MSR_IE
128 mts rmsr, r11
129 .endm
131 .macro set_ums
132 mfs r11, rmsr
133 ori r11, r11, MSR_VMS
134 andni r11, r11, MSR_UMS
135 mts rmsr, r11
136 .endm
138 .macro set_vms
139 mfs r11, rmsr
140 ori r11, r11, MSR_VMS
141 andni r11, r11, MSR_UMS
142 mts rmsr, r11
143 .endm
145 .macro clear_ums
146 mfs r11, rmsr
147 andni r11, r11, MSR_UMS
148 mts rmsr,r11
149 .endm
151 .macro clear_vms_ums
152 mfs r11, rmsr
153 andni r11, r11, (MSR_VMS|MSR_UMS)
154 mts rmsr,r11
155 .endm
156 #endif
158 /* Define how to call high-level functions. With MMU, virtual mode must be
159 * enabled when calling the high-level function. Clobbers R11.
160 * VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL
161 */
163 /* turn on virtual protected mode save */
164 #define VM_ON \
165 set_ums; \
166 rted r0, 2f; \
167 nop; \
168 2:
170 /* turn off virtual protected mode save and user mode save*/
171 #define VM_OFF \
172 clear_vms_ums; \
173 rted r0, TOPHYS(1f); \
174 nop; \
175 1:
177 #define SAVE_REGS \
178 swi r2, r1, PT_R2; /* Save SDA */ \
179 swi r3, r1, PT_R3; \
180 swi r4, r1, PT_R4; \
181 swi r5, r1, PT_R5; \
182 swi r6, r1, PT_R6; \
183 swi r7, r1, PT_R7; \
184 swi r8, r1, PT_R8; \
185 swi r9, r1, PT_R9; \
186 swi r10, r1, PT_R10; \
187 swi r11, r1, PT_R11; /* save clobbered regs after rval */\
188 swi r12, r1, PT_R12; \
189 swi r13, r1, PT_R13; /* Save SDA2 */ \
190 swi r14, r1, PT_PC; /* PC, before IRQ/trap */ \
191 swi r15, r1, PT_R15; /* Save LP */ \
192 swi r16, r1, PT_R16; \
193 swi r17, r1, PT_R17; \
194 swi r18, r1, PT_R18; /* Save asm scratch reg */ \
195 swi r19, r1, PT_R19; \
196 swi r20, r1, PT_R20; \
197 swi r21, r1, PT_R21; \
198 swi r22, r1, PT_R22; \
199 swi r23, r1, PT_R23; \
200 swi r24, r1, PT_R24; \
201 swi r25, r1, PT_R25; \
202 swi r26, r1, PT_R26; \
203 swi r27, r1, PT_R27; \
204 swi r28, r1, PT_R28; \
205 swi r29, r1, PT_R29; \
206 swi r30, r1, PT_R30; \
207 swi r31, r1, PT_R31; /* Save current task reg */ \
208 mfs r11, rmsr; /* save MSR */ \
209 swi r11, r1, PT_MSR;
211 #define RESTORE_REGS \
212 lwi r11, r1, PT_MSR; \
213 mts rmsr , r11; \
214 lwi r2, r1, PT_R2; /* restore SDA */ \
215 lwi r3, r1, PT_R3; \
216 lwi r4, r1, PT_R4; \
217 lwi r5, r1, PT_R5; \
218 lwi r6, r1, PT_R6; \
219 lwi r7, r1, PT_R7; \
220 lwi r8, r1, PT_R8; \
221 lwi r9, r1, PT_R9; \
222 lwi r10, r1, PT_R10; \
223 lwi r11, r1, PT_R11; /* restore clobbered regs after rval */\
224 lwi r12, r1, PT_R12; \
225 lwi r13, r1, PT_R13; /* restore SDA2 */ \
226 lwi r14, r1, PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
227 lwi r15, r1, PT_R15; /* restore LP */ \
228 lwi r16, r1, PT_R16; \
229 lwi r17, r1, PT_R17; \
230 lwi r18, r1, PT_R18; /* restore asm scratch reg */ \
231 lwi r19, r1, PT_R19; \
232 lwi r20, r1, PT_R20; \
233 lwi r21, r1, PT_R21; \
234 lwi r22, r1, PT_R22; \
235 lwi r23, r1, PT_R23; \
236 lwi r24, r1, PT_R24; \
237 lwi r25, r1, PT_R25; \
238 lwi r26, r1, PT_R26; \
239 lwi r27, r1, PT_R27; \
240 lwi r28, r1, PT_R28; \
241 lwi r29, r1, PT_R29; \
242 lwi r30, r1, PT_R30; \
243 lwi r31, r1, PT_R31; /* Restore cur task reg */
245 #define SAVE_STATE \
246 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \
247 /* See if already in kernel mode.*/ \
248 mfs r1, rmsr; \
249 andi r1, r1, MSR_UMS; \
250 bnei r1, 1f; \
251 /* Kernel-mode state save. */ \
252 /* Reload kernel stack-ptr. */ \
253 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
254 /* FIXME: I can add these two lines to one */ \
255 /* tophys(r1,r1); */ \
256 /* addik r1, r1, -PT_SIZE; */ \
257 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
258 SAVE_REGS \
259 brid 2f; \
260 swi r1, r1, PT_MODE; \
261 1: /* User-mode state save. */ \
262 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
263 tophys(r1,r1); \
264 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
265 /* MS these three instructions can be added to one */ \
266 /* addik r1, r1, THREAD_SIZE; */ \
267 /* tophys(r1,r1); */ \
268 /* addik r1, r1, -PT_SIZE; */ \
269 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
270 SAVE_REGS \
271 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
272 swi r11, r1, PT_R1; /* Store user SP. */ \
273 swi r0, r1, PT_MODE; /* Was in user-mode. */ \
274 /* MS: I am clearing UMS even in case when I come from kernel space */ \
275 clear_ums; \
276 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
278 .text
280 /*
281 * User trap.
282 *
283 * System calls are handled here.
284 *
285 * Syscall protocol:
286 * Syscall number in r12, args in r5-r10
287 * Return value in r3
288 *
289 * Trap entered via brki instruction, so BIP bit is set, and interrupts
290 * are masked. This is nice, means we don't have to CLI before state save
291 */
292 C_ENTRY(_user_exception):
293 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
294 addi r14, r14, 4 /* return address is 4 byte after call */
296 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
297 tophys(r1,r1);
298 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
299 /* calculate kernel stack pointer from task struct 8k */
300 addik r1, r1, THREAD_SIZE;
301 tophys(r1,r1);
303 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
304 SAVE_REGS
305 swi r0, r1, PT_R3
306 swi r0, r1, PT_R4
308 swi r0, r1, PT_MODE; /* Was in user-mode. */
309 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
310 swi r11, r1, PT_R1; /* Store user SP. */
311 clear_ums;
312 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
313 /* Save away the syscall number. */
314 swi r12, r1, PT_R0;
315 tovirt(r1,r1)
317 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
318 /* Jump to the appropriate function for the system call number in r12
319 * (r12 is not preserved), or return an error if r12 is not valid. The LP
320 * register should point to the location where
321 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */
323 /* Step into virtual mode */
324 rtbd r0, 3f
325 nop
326 3:
327 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
328 lwi r11, r11, TI_FLAGS /* get flags in thread info */
329 andi r11, r11, _TIF_WORK_SYSCALL_MASK
330 beqi r11, 4f
332 addik r3, r0, -ENOSYS
333 swi r3, r1, PT_R3
334 brlid r15, do_syscall_trace_enter
335 addik r5, r1, PT_R0
337 # do_syscall_trace_enter returns the new syscall nr.
338 addk r12, r0, r3
339 lwi r5, r1, PT_R5;
340 lwi r6, r1, PT_R6;
341 lwi r7, r1, PT_R7;
342 lwi r8, r1, PT_R8;
343 lwi r9, r1, PT_R9;
344 lwi r10, r1, PT_R10;
345 4:
346 /* Jump to the appropriate function for the system call number in r12
347 * (r12 is not preserved), or return an error if r12 is not valid.
348 * The LP register should point to the location where the called function
349 * should return. [note that MAKE_SYS_CALL uses label 1] */
350 /* See if the system call number is valid */
351 blti r12, 5f
352 addi r11, r12, -__NR_syscalls;
353 bgei r11, 5f;
354 /* Figure out which function to use for this system call. */
355 /* Note Microblaze barrel shift is optional, so don't rely on it */
356 add r12, r12, r12; /* convert num -> ptr */
357 add r12, r12, r12;
358 addi r30, r0, 1 /* restarts allowed */
360 #ifdef DEBUG
361 /* Trac syscalls and stored them to syscall_debug_table */
362 /* The first syscall location stores total syscall number */
363 lwi r3, r0, syscall_debug_table
364 addi r3, r3, 1
365 swi r3, r0, syscall_debug_table
366 lwi r3, r12, syscall_debug_table
367 addi r3, r3, 1
368 swi r3, r12, syscall_debug_table
369 #endif
371 # Find and jump into the syscall handler.
372 lwi r12, r12, sys_call_table
373 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
374 addi r15, r0, ret_from_trap-8
375 bra r12
377 /* The syscall number is invalid, return an error. */
378 5:
379 braid ret_from_trap
380 addi r3, r0, -ENOSYS;
382 /* Entry point used to return from a syscall/trap */
383 /* We re-enable BIP bit before state restore */
384 C_ENTRY(ret_from_trap):
385 swi r3, r1, PT_R3
386 swi r4, r1, PT_R4
388 lwi r11, r1, PT_MODE;
389 /* See if returning to kernel mode, if so, skip resched &c. */
390 bnei r11, 2f;
391 /* We're returning to user mode, so check for various conditions that
392 * trigger rescheduling. */
393 /* FIXME: Restructure all these flag checks. */
394 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
395 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
396 andi r11, r11, _TIF_WORK_SYSCALL_MASK
397 beqi r11, 1f
399 brlid r15, do_syscall_trace_leave
400 addik r5, r1, PT_R0
401 1:
402 /* We're returning to user mode, so check for various conditions that
403 * trigger rescheduling. */
404 /* get thread info from current task */
405 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
406 lwi r19, r11, TI_FLAGS; /* get flags in thread info */
407 andi r11, r19, _TIF_NEED_RESCHED;
408 beqi r11, 5f;
410 bralid r15, schedule; /* Call scheduler */
411 nop; /* delay slot */
412 bri 1b
414 /* Maybe handle a signal */
415 5:
416 andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
417 beqi r11, 4f; /* Signals to handle, handle them */
419 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
420 bralid r15, do_notify_resume; /* Handle any signals */
421 add r6, r30, r0; /* Arg 2: int in_syscall */
422 add r30, r0, r0 /* no more restarts */
423 bri 1b
425 /* Finally, return to user state. */
426 4: set_bip; /* Ints masked for state restore */
427 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
428 VM_OFF;
429 tophys(r1,r1);
430 RESTORE_REGS;
431 addik r1, r1, PT_SIZE /* Clean up stack space. */
432 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
433 bri 6f;
435 /* Return to kernel state. */
436 2: set_bip; /* Ints masked for state restore */
437 VM_OFF;
438 tophys(r1,r1);
439 RESTORE_REGS;
440 addik r1, r1, PT_SIZE /* Clean up stack space. */
441 tovirt(r1,r1);
442 6:
443 TRAP_return: /* Make global symbol for debugging */
444 rtbd r14, 0; /* Instructions to return from an IRQ */
445 nop;
448 /* This the initial entry point for a new child thread, with an appropriate
449 stack in place that makes it look the the child is in the middle of an
450 syscall. This function is actually `returned to' from switch_thread
451 (copy_thread makes ret_from_fork the return address in each new thread's
452 saved context). */
453 C_ENTRY(ret_from_fork):
454 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
455 add r5, r3, r0; /* switch_thread returns the prev task */
456 /* ( in the delay slot ) */
457 brid ret_from_trap; /* Do normal trap return */
458 add r3, r0, r0; /* Child's fork call should return 0. */
460 C_ENTRY(ret_from_kernel_thread):
461 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
462 add r5, r3, r0; /* switch_thread returns the prev task */
463 /* ( in the delay slot ) */
464 brald r15, r20 /* fn was left in r20 */
465 addk r5, r0, r19 /* ... and argument - in r19 */
466 brid ret_from_trap
467 add r3, r0, r0
469 C_ENTRY(sys_rt_sigreturn_wrapper):
470 addik r30, r0, 0 /* no restarts */
471 brid sys_rt_sigreturn /* Do real work */
472 addik r5, r1, 0; /* add user context as 1st arg */
474 /*
475 * HW EXCEPTION rutine start
476 */
477 C_ENTRY(full_exception_trap):
478 /* adjust exception address for privileged instruction
479 * for finding where is it */
480 addik r17, r17, -4
481 SAVE_STATE /* Save registers */
482 /* PC, before IRQ/trap - this is one instruction above */
483 swi r17, r1, PT_PC;
484 tovirt(r1,r1)
485 /* FIXME this can be store directly in PT_ESR reg.
486 * I tested it but there is a fault */
487 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
488 addik r15, r0, ret_from_exc - 8
489 mfs r6, resr
490 mfs r7, rfsr; /* save FSR */
491 mts rfsr, r0; /* Clear sticky fsr */
492 rted r0, full_exception
493 addik r5, r1, 0 /* parameter struct pt_regs * regs */
495 /*
496 * Unaligned data trap.
497 *
498 * Unaligned data trap last on 4k page is handled here.
499 *
500 * Trap entered via exception, so EE bit is set, and interrupts
501 * are masked. This is nice, means we don't have to CLI before state save
502 *
503 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
504 */
505 C_ENTRY(unaligned_data_trap):
506 /* MS: I have to save r11 value and then restore it because
507 * set_bit, clear_eip, set_ee use r11 as temp register if MSR
508 * instructions are not used. We don't need to do if MSR instructions
509 * are used and they use r0 instead of r11.
510 * I am using ENTRY_SP which should be primary used only for stack
511 * pointer saving. */
512 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
513 set_bip; /* equalize initial state for all possible entries */
514 clear_eip;
515 set_ee;
516 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
517 SAVE_STATE /* Save registers.*/
518 /* PC, before IRQ/trap - this is one instruction above */
519 swi r17, r1, PT_PC;
520 tovirt(r1,r1)
521 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
522 addik r15, r0, ret_from_exc-8
523 mfs r3, resr /* ESR */
524 mfs r4, rear /* EAR */
525 rtbd r0, _unaligned_data_exception
526 addik r7, r1, 0 /* parameter struct pt_regs * regs */
528 /*
529 * Page fault traps.
530 *
531 * If the real exception handler (from hw_exception_handler.S) didn't find
532 * the mapping for the process, then we're thrown here to handle such situation.
533 *
534 * Trap entered via exceptions, so EE bit is set, and interrupts
535 * are masked. This is nice, means we don't have to CLI before state save
536 *
537 * Build a standard exception frame for TLB Access errors. All TLB exceptions
538 * will bail out to this point if they can't resolve the lightweight TLB fault.
539 *
540 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
541 * void do_page_fault(struct pt_regs *regs,
542 * unsigned long address,
543 * unsigned long error_code)
544 */
545 /* data and intruction trap - which is choose is resolved int fault.c */
546 C_ENTRY(page_fault_data_trap):
547 SAVE_STATE /* Save registers.*/
548 /* PC, before IRQ/trap - this is one instruction above */
549 swi r17, r1, PT_PC;
550 tovirt(r1,r1)
551 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
552 addik r15, r0, ret_from_exc-8
553 mfs r6, rear /* parameter unsigned long address */
554 mfs r7, resr /* parameter unsigned long error_code */
555 rted r0, do_page_fault
556 addik r5, r1, 0 /* parameter struct pt_regs * regs */
558 C_ENTRY(page_fault_instr_trap):
559 SAVE_STATE /* Save registers.*/
560 /* PC, before IRQ/trap - this is one instruction above */
561 swi r17, r1, PT_PC;
562 tovirt(r1,r1)
563 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
564 addik r15, r0, ret_from_exc-8
565 mfs r6, rear /* parameter unsigned long address */
566 ori r7, r0, 0 /* parameter unsigned long error_code */
567 rted r0, do_page_fault
568 addik r5, r1, 0 /* parameter struct pt_regs * regs */
570 /* Entry point used to return from an exception. */
571 C_ENTRY(ret_from_exc):
572 lwi r11, r1, PT_MODE;
573 bnei r11, 2f; /* See if returning to kernel mode, */
574 /* ... if so, skip resched &c. */
576 /* We're returning to user mode, so check for various conditions that
577 trigger rescheduling. */
578 1:
579 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
580 lwi r19, r11, TI_FLAGS; /* get flags in thread info */
581 andi r11, r19, _TIF_NEED_RESCHED;
582 beqi r11, 5f;
584 /* Call the scheduler before returning from a syscall/trap. */
585 bralid r15, schedule; /* Call scheduler */
586 nop; /* delay slot */
587 bri 1b
589 /* Maybe handle a signal */
590 5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
591 beqi r11, 4f; /* Signals to handle, handle them */
593 /*
594 * Handle a signal return; Pending signals should be in r18.
595 *
596 * Not all registers are saved by the normal trap/interrupt entry
597 * points (for instance, call-saved registers (because the normal
598 * C-compiler calling sequence in the kernel makes sure they're
599 * preserved), and call-clobbered registers in the case of
600 * traps), but signal handlers may want to examine or change the
601 * complete register state. Here we save anything not saved by
602 * the normal entry sequence, so that it may be safely restored
603 * (in a possibly modified form) after do_notify_resume returns. */
604 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
605 bralid r15, do_notify_resume; /* Handle any signals */
606 addi r6, r0, 0; /* Arg 2: int in_syscall */
607 bri 1b
609 /* Finally, return to user state. */
610 4: set_bip; /* Ints masked for state restore */
611 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
612 VM_OFF;
613 tophys(r1,r1);
615 RESTORE_REGS;
616 addik r1, r1, PT_SIZE /* Clean up stack space. */
618 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
619 bri 6f;
620 /* Return to kernel state. */
621 2: set_bip; /* Ints masked for state restore */
622 VM_OFF;
623 tophys(r1,r1);
624 RESTORE_REGS;
625 addik r1, r1, PT_SIZE /* Clean up stack space. */
627 tovirt(r1,r1);
628 6:
629 EXC_return: /* Make global symbol for debugging */
630 rtbd r14, 0; /* Instructions to return from an IRQ */
631 nop;
633 /*
634 * HW EXCEPTION rutine end
635 */
637 /*
638 * Hardware maskable interrupts.
639 *
640 * The stack-pointer (r1) should have already been saved to the memory
641 * location PER_CPU(ENTRY_SP).
642 */
643 C_ENTRY(_interrupt):
644 /* MS: we are in physical address */
645 /* Save registers, switch to proper stack, convert SP to virtual.*/
646 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
647 /* MS: See if already in kernel mode. */
648 mfs r1, rmsr
649 nop
650 andi r1, r1, MSR_UMS
651 bnei r1, 1f
653 /* Kernel-mode state save. */
654 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
655 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
656 /* save registers */
657 /* MS: Make room on the stack -> activation record */
658 addik r1, r1, -PT_SIZE;
659 SAVE_REGS
660 brid 2f;
661 swi r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */
662 1:
663 /* User-mode state save. */
664 /* MS: get the saved current */
665 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
666 tophys(r1,r1);
667 lwi r1, r1, TS_THREAD_INFO;
668 addik r1, r1, THREAD_SIZE;
669 tophys(r1,r1);
670 /* save registers */
671 addik r1, r1, -PT_SIZE;
672 SAVE_REGS
673 /* calculate mode */
674 swi r0, r1, PT_MODE;
675 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
676 swi r11, r1, PT_R1;
677 clear_ums;
678 2:
679 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
680 tovirt(r1,r1)
681 addik r15, r0, irq_call;
682 irq_call:rtbd r0, do_IRQ;
683 addik r5, r1, 0;
685 /* MS: we are in virtual mode */
686 ret_from_irq:
687 lwi r11, r1, PT_MODE;
688 bnei r11, 2f;
690 1:
691 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
692 lwi r19, r11, TI_FLAGS; /* MS: get flags from thread info */
693 andi r11, r19, _TIF_NEED_RESCHED;
694 beqi r11, 5f
695 bralid r15, schedule;
696 nop; /* delay slot */
697 bri 1b
699 /* Maybe handle a signal */
700 5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
701 beqid r11, no_intr_resched
702 /* Handle a signal return; Pending signals should be in r18. */
703 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
704 bralid r15, do_notify_resume; /* Handle any signals */
705 addi r6, r0, 0; /* Arg 2: int in_syscall */
706 bri 1b
708 /* Finally, return to user state. */
709 no_intr_resched:
710 /* Disable interrupts, we are now committed to the state restore */
711 disable_irq
712 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
713 VM_OFF;
714 tophys(r1,r1);
715 RESTORE_REGS
716 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
717 lwi r1, r1, PT_R1 - PT_SIZE;
718 bri 6f;
719 /* MS: Return to kernel state. */
720 2:
721 #ifdef CONFIG_PREEMPT
722 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
723 /* MS: get preempt_count from thread info */
724 lwi r5, r11, TI_PREEMPT_COUNT;
725 bgti r5, restore;
727 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
728 andi r5, r5, _TIF_NEED_RESCHED;
729 beqi r5, restore /* if zero jump over */
731 preempt:
732 /* interrupts are off that's why I am calling preempt_chedule_irq */
733 bralid r15, preempt_schedule_irq
734 nop
735 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
736 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
737 andi r5, r5, _TIF_NEED_RESCHED;
738 bnei r5, preempt /* if non zero jump to resched */
739 restore:
740 #endif
741 VM_OFF /* MS: turn off MMU */
742 tophys(r1,r1)
743 RESTORE_REGS
744 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
745 tovirt(r1,r1);
746 6:
747 IRQ_return: /* MS: Make global symbol for debugging */
748 rtid r14, 0
749 nop
751 /*
752 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
753 * and call handling function with saved pt_regs
754 */
755 C_ENTRY(_debug_exception):
756 /* BIP bit is set on entry, no interrupts can occur */
757 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
759 mfs r1, rmsr
760 nop
761 andi r1, r1, MSR_UMS
762 bnei r1, 1f
763 /* MS: Kernel-mode state save - kgdb */
764 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
766 /* BIP bit is set on entry, no interrupts can occur */
767 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE;
768 SAVE_REGS;
769 /* save all regs to pt_reg structure */
770 swi r0, r1, PT_R0; /* R0 must be saved too */
771 swi r14, r1, PT_R14 /* rewrite saved R14 value */
772 swi r16, r1, PT_PC; /* PC and r16 are the same */
773 /* save special purpose registers to pt_regs */
774 mfs r11, rear;
775 swi r11, r1, PT_EAR;
776 mfs r11, resr;
777 swi r11, r1, PT_ESR;
778 mfs r11, rfsr;
779 swi r11, r1, PT_FSR;
781 /* stack pointer is in physical address at it is decrease
782 * by PT_SIZE but we need to get correct R1 value */
783 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE;
784 swi r11, r1, PT_R1
785 /* MS: r31 - current pointer isn't changed */
786 tovirt(r1,r1)
787 #ifdef CONFIG_KGDB
788 addi r5, r1, 0 /* pass pt_reg address as the first arg */
789 addik r15, r0, dbtrap_call; /* return address */
790 rtbd r0, microblaze_kgdb_break
791 nop;
792 #endif
793 /* MS: Place handler for brki from kernel space if KGDB is OFF.
794 * It is very unlikely that another brki instruction is called. */
795 bri 0
797 /* MS: User-mode state save - gdb */
798 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
799 tophys(r1,r1);
800 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
801 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
802 tophys(r1,r1);
804 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
805 SAVE_REGS;
806 swi r16, r1, PT_PC; /* Save LP */
807 swi r0, r1, PT_MODE; /* Was in user-mode. */
808 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
809 swi r11, r1, PT_R1; /* Store user SP. */
810 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
811 tovirt(r1,r1)
812 set_vms;
813 addik r5, r1, 0;
814 addik r15, r0, dbtrap_call;
815 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
816 rtbd r0, sw_exception
817 nop
819 /* MS: The first instruction for the second part of the gdb/kgdb */
820 set_bip; /* Ints masked for state restore */
821 lwi r11, r1, PT_MODE;
822 bnei r11, 2f;
823 /* MS: Return to user space - gdb */
824 1:
825 /* Get current task ptr into r11 */
826 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
827 lwi r19, r11, TI_FLAGS; /* get flags in thread info */
828 andi r11, r19, _TIF_NEED_RESCHED;
829 beqi r11, 5f;
831 /* Call the scheduler before returning from a syscall/trap. */
832 bralid r15, schedule; /* Call scheduler */
833 nop; /* delay slot */
834 bri 1b
836 /* Maybe handle a signal */
837 5: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
838 beqi r11, 4f; /* Signals to handle, handle them */
840 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
841 bralid r15, do_notify_resume; /* Handle any signals */
842 addi r6, r0, 0; /* Arg 2: int in_syscall */
843 bri 1b
845 /* Finally, return to user state. */
846 4: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
847 VM_OFF;
848 tophys(r1,r1);
849 /* MS: Restore all regs */
850 RESTORE_REGS
851 addik r1, r1, PT_SIZE /* Clean up stack space */
852 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
853 DBTRAP_return_user: /* MS: Make global symbol for debugging */
854 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
855 nop;
857 /* MS: Return to kernel state - kgdb */
858 2: VM_OFF;
859 tophys(r1,r1);
860 /* MS: Restore all regs */
861 RESTORE_REGS
862 lwi r14, r1, PT_R14;
863 lwi r16, r1, PT_PC;
864 addik r1, r1, PT_SIZE; /* MS: Clean up stack space */
865 tovirt(r1,r1);
866 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
867 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
868 nop;
871 ENTRY(_switch_to)
872 /* prepare return value */
873 addk r3, r0, CURRENT_TASK
875 /* save registers in cpu_context */
876 /* use r11 and r12, volatile registers, as temp register */
877 /* give start of cpu_context for previous process */
878 addik r11, r5, TI_CPU_CONTEXT
879 swi r1, r11, CC_R1
880 swi r2, r11, CC_R2
881 /* skip volatile registers.
882 * they are saved on stack when we jumped to _switch_to() */
883 /* dedicated registers */
884 swi r13, r11, CC_R13
885 swi r14, r11, CC_R14
886 swi r15, r11, CC_R15
887 swi r16, r11, CC_R16
888 swi r17, r11, CC_R17
889 swi r18, r11, CC_R18
890 /* save non-volatile registers */
891 swi r19, r11, CC_R19
892 swi r20, r11, CC_R20
893 swi r21, r11, CC_R21
894 swi r22, r11, CC_R22
895 swi r23, r11, CC_R23
896 swi r24, r11, CC_R24
897 swi r25, r11, CC_R25
898 swi r26, r11, CC_R26
899 swi r27, r11, CC_R27
900 swi r28, r11, CC_R28
901 swi r29, r11, CC_R29
902 swi r30, r11, CC_R30
903 /* special purpose registers */
904 mfs r12, rmsr
905 swi r12, r11, CC_MSR
906 mfs r12, rear
907 swi r12, r11, CC_EAR
908 mfs r12, resr
909 swi r12, r11, CC_ESR
910 mfs r12, rfsr
911 swi r12, r11, CC_FSR
913 /* update r31, the current-give me pointer to task which will be next */
914 lwi CURRENT_TASK, r6, TI_TASK
915 /* stored it to current_save too */
916 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
918 /* get new process' cpu context and restore */
919 /* give me start where start context of next task */
920 addik r11, r6, TI_CPU_CONTEXT
922 /* non-volatile registers */
923 lwi r30, r11, CC_R30
924 lwi r29, r11, CC_R29
925 lwi r28, r11, CC_R28
926 lwi r27, r11, CC_R27
927 lwi r26, r11, CC_R26
928 lwi r25, r11, CC_R25
929 lwi r24, r11, CC_R24
930 lwi r23, r11, CC_R23
931 lwi r22, r11, CC_R22
932 lwi r21, r11, CC_R21
933 lwi r20, r11, CC_R20
934 lwi r19, r11, CC_R19
935 /* dedicated registers */
936 lwi r18, r11, CC_R18
937 lwi r17, r11, CC_R17
938 lwi r16, r11, CC_R16
939 lwi r15, r11, CC_R15
940 lwi r14, r11, CC_R14
941 lwi r13, r11, CC_R13
942 /* skip volatile registers */
943 lwi r2, r11, CC_R2
944 lwi r1, r11, CC_R1
946 /* special purpose registers */
947 lwi r12, r11, CC_FSR
948 mts rfsr, r12
949 lwi r12, r11, CC_MSR
950 mts rmsr, r12
952 rtsd r15, 8
953 nop
955 ENTRY(_reset)
956 brai 0; /* Jump to reset vector */
958 /* These are compiled and loaded into high memory, then
959 * copied into place in mach_early_setup */
960 .section .init.ivt, "ax"
961 #if CONFIG_MANUAL_RESET_VECTOR
962 .org 0x0
963 brai CONFIG_MANUAL_RESET_VECTOR
964 #endif
965 .org 0x8
966 brai TOPHYS(_user_exception); /* syscall handler */
967 .org 0x10
968 brai TOPHYS(_interrupt); /* Interrupt handler */
969 .org 0x18
970 brai TOPHYS(_debug_exception); /* debug trap handler */
971 .org 0x20
972 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
974 .section .rodata,"a"
975 #include "syscall_table.S"
977 syscall_table_size=(.-sys_call_table)
979 type_SYSCALL:
980 .ascii "SYSCALL\0"
981 type_IRQ:
982 .ascii "IRQ\0"
983 type_IRQ_PREEMPT:
984 .ascii "IRQ (PREEMPTED)\0"
985 type_SYSCALL_PREEMPT:
986 .ascii " SYSCALL (PREEMPTED)\0"
988 /*
989 * Trap decoding for stack unwinder
990 * Tuples are (start addr, end addr, string)
991 * If return address lies on [start addr, end addr],
992 * unwinder displays 'string'
993 */
995 .align 4
996 .global microblaze_trap_handlers
997 microblaze_trap_handlers:
998 /* Exact matches come first */
999 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
1000 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
1001 /* Fuzzy matches go here */
1002 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
1003 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1004 /* End of table */
1005 .word 0 ; .word 0 ; .word 0