| blob | ff949e362968db6881481abab10d48217020f6df |
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 mfs r1, rmsr
297 nop
298 andi r1, r1, MSR_UMS
299 bnei r1, 1f
301 /* Kernel-mode state save - kernel execve */
302 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
303 tophys(r1,r1);
305 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
306 SAVE_REGS
308 swi r1, r1, PT_MODE; /* pt_regs -> kernel mode */
309 brid 2f;
310 nop; /* Fill delay slot */
312 /* User-mode state save. */
313 1:
314 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
315 tophys(r1,r1);
316 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
317 /* calculate kernel stack pointer from task struct 8k */
318 addik r1, r1, THREAD_SIZE;
319 tophys(r1,r1);
321 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
322 SAVE_REGS
323 swi r0, r1, PT_R3
324 swi r0, r1, PT_R4
326 swi r0, r1, PT_MODE; /* Was in user-mode. */
327 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
328 swi r11, r1, PT_R1; /* Store user SP. */
329 clear_ums;
330 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
331 /* Save away the syscall number. */
332 swi r12, r1, PT_R0;
333 tovirt(r1,r1)
335 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
336 /* Jump to the appropriate function for the system call number in r12
337 * (r12 is not preserved), or return an error if r12 is not valid. The LP
338 * register should point to the location where
339 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */
341 /* Step into virtual mode */
342 rtbd r0, 3f
343 nop
344 3:
345 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
346 lwi r11, r11, TI_FLAGS /* get flags in thread info */
347 andi r11, r11, _TIF_WORK_SYSCALL_MASK
348 beqi r11, 4f
350 addik r3, r0, -ENOSYS
351 swi r3, r1, PT_R3
352 brlid r15, do_syscall_trace_enter
353 addik r5, r1, PT_R0
355 # do_syscall_trace_enter returns the new syscall nr.
356 addk r12, r0, r3
357 lwi r5, r1, PT_R5;
358 lwi r6, r1, PT_R6;
359 lwi r7, r1, PT_R7;
360 lwi r8, r1, PT_R8;
361 lwi r9, r1, PT_R9;
362 lwi r10, r1, PT_R10;
363 4:
364 /* Jump to the appropriate function for the system call number in r12
365 * (r12 is not preserved), or return an error if r12 is not valid.
366 * The LP register should point to the location where the called function
367 * should return. [note that MAKE_SYS_CALL uses label 1] */
368 /* See if the system call number is valid */
369 addi r11, r12, -__NR_syscalls;
370 bgei r11,5f;
371 /* Figure out which function to use for this system call. */
372 /* Note Microblaze barrel shift is optional, so don't rely on it */
373 add r12, r12, r12; /* convert num -> ptr */
374 add r12, r12, r12;
376 #ifdef DEBUG
377 /* Trac syscalls and stored them to syscall_debug_table */
378 /* The first syscall location stores total syscall number */
379 lwi r3, r0, syscall_debug_table
380 addi r3, r3, 1
381 swi r3, r0, syscall_debug_table
382 lwi r3, r12, syscall_debug_table
383 addi r3, r3, 1
384 swi r3, r12, syscall_debug_table
385 #endif
387 # Find and jump into the syscall handler.
388 lwi r12, r12, sys_call_table
389 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
390 addi r15, r0, ret_from_trap-8
391 bra r12
393 /* The syscall number is invalid, return an error. */
394 5:
395 rtsd r15, 8; /* looks like a normal subroutine return */
396 addi r3, r0, -ENOSYS;
398 /* Entry point used to return from a syscall/trap */
399 /* We re-enable BIP bit before state restore */
400 C_ENTRY(ret_from_trap):
401 swi r3, r1, PT_R3
402 swi r4, r1, PT_R4
404 lwi r11, r1, PT_MODE;
405 /* See if returning to kernel mode, if so, skip resched &c. */
406 bnei r11, 2f;
407 /* We're returning to user mode, so check for various conditions that
408 * trigger rescheduling. */
409 /* FIXME: Restructure all these flag checks. */
410 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
411 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
412 andi r11, r11, _TIF_WORK_SYSCALL_MASK
413 beqi r11, 1f
415 brlid r15, do_syscall_trace_leave
416 addik r5, r1, PT_R0
417 1:
418 /* We're returning to user mode, so check for various conditions that
419 * trigger rescheduling. */
420 /* get thread info from current task */
421 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
422 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
423 andi r11, r11, _TIF_NEED_RESCHED;
424 beqi r11, 5f;
426 bralid r15, schedule; /* Call scheduler */
427 nop; /* delay slot */
429 /* Maybe handle a signal */
430 5: /* get thread info from current task*/
431 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
432 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
433 andi r11, r11, _TIF_SIGPENDING;
434 beqi r11, 1f; /* Signals to handle, handle them */
436 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
437 addi r7, r0, 1; /* Arg 3: int in_syscall */
438 bralid r15, do_signal; /* Handle any signals */
439 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
441 /* Finally, return to user state. */
442 1: set_bip; /* Ints masked for state restore */
443 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
444 VM_OFF;
445 tophys(r1,r1);
446 RESTORE_REGS;
447 addik r1, r1, PT_SIZE /* Clean up stack space. */
448 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
449 bri 6f;
451 /* Return to kernel state. */
452 2: set_bip; /* Ints masked for state restore */
453 VM_OFF;
454 tophys(r1,r1);
455 RESTORE_REGS;
456 addik r1, r1, PT_SIZE /* Clean up stack space. */
457 tovirt(r1,r1);
458 6:
459 TRAP_return: /* Make global symbol for debugging */
460 rtbd r14, 0; /* Instructions to return from an IRQ */
461 nop;
464 /* These syscalls need access to the struct pt_regs on the stack, so we
465 implement them in assembly (they're basically all wrappers anyway). */
467 C_ENTRY(sys_fork_wrapper):
468 addi r5, r0, SIGCHLD /* Arg 0: flags */
469 lwi r6, r1, PT_R1 /* Arg 1: child SP (use parent's) */
470 addik r7, r1, 0 /* Arg 2: parent context */
471 add r8. r0, r0 /* Arg 3: (unused) */
472 add r9, r0, r0; /* Arg 4: (unused) */
473 brid do_fork /* Do real work (tail-call) */
474 add r10, r0, r0; /* Arg 5: (unused) */
476 /* This the initial entry point for a new child thread, with an appropriate
477 stack in place that makes it look the the child is in the middle of an
478 syscall. This function is actually `returned to' from switch_thread
479 (copy_thread makes ret_from_fork the return address in each new thread's
480 saved context). */
481 C_ENTRY(ret_from_fork):
482 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
483 add r3, r5, r0; /* switch_thread returns the prev task */
484 /* ( in the delay slot ) */
485 brid ret_from_trap; /* Do normal trap return */
486 add r3, r0, r0; /* Child's fork call should return 0. */
488 C_ENTRY(sys_vfork):
489 brid microblaze_vfork /* Do real work (tail-call) */
490 addik r5, r1, 0
492 C_ENTRY(sys_clone):
493 bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
494 lwi r6, r1, PT_R1; /* If so, use paret's stack ptr */
495 1: addik r7, r1, 0; /* Arg 2: parent context */
496 add r8, r0, r0; /* Arg 3: (unused) */
497 add r9, r0, r0; /* Arg 4: (unused) */
498 brid do_fork /* Do real work (tail-call) */
499 add r10, r0, r0; /* Arg 5: (unused) */
501 C_ENTRY(sys_execve):
502 brid microblaze_execve; /* Do real work (tail-call).*/
503 addik r8, r1, 0; /* add user context as 4th arg */
505 C_ENTRY(sys_rt_sigreturn_wrapper):
506 brid sys_rt_sigreturn /* Do real work */
507 addik r5, r1, 0; /* add user context as 1st arg */
509 /*
510 * HW EXCEPTION rutine start
511 */
512 C_ENTRY(full_exception_trap):
513 /* adjust exception address for privileged instruction
514 * for finding where is it */
515 addik r17, r17, -4
516 SAVE_STATE /* Save registers */
517 /* PC, before IRQ/trap - this is one instruction above */
518 swi r17, r1, PT_PC;
519 tovirt(r1,r1)
520 /* FIXME this can be store directly in PT_ESR reg.
521 * I tested it but there is a fault */
522 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
523 addik r15, r0, ret_from_exc - 8
524 mfs r6, resr
525 mfs r7, rfsr; /* save FSR */
526 mts rfsr, r0; /* Clear sticky fsr */
527 rted r0, full_exception
528 addik r5, r1, 0 /* parameter struct pt_regs * regs */
530 /*
531 * Unaligned data trap.
532 *
533 * Unaligned data trap last on 4k page is handled here.
534 *
535 * Trap entered via exception, so EE bit is set, and interrupts
536 * are masked. This is nice, means we don't have to CLI before state save
537 *
538 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
539 */
540 C_ENTRY(unaligned_data_trap):
541 /* MS: I have to save r11 value and then restore it because
542 * set_bit, clear_eip, set_ee use r11 as temp register if MSR
543 * instructions are not used. We don't need to do if MSR instructions
544 * are used and they use r0 instead of r11.
545 * I am using ENTRY_SP which should be primary used only for stack
546 * pointer saving. */
547 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
548 set_bip; /* equalize initial state for all possible entries */
549 clear_eip;
550 set_ee;
551 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
552 SAVE_STATE /* Save registers.*/
553 /* PC, before IRQ/trap - this is one instruction above */
554 swi r17, r1, PT_PC;
555 tovirt(r1,r1)
556 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
557 addik r15, r0, ret_from_exc-8
558 mfs r3, resr /* ESR */
559 mfs r4, rear /* EAR */
560 rtbd r0, _unaligned_data_exception
561 addik r7, r1, 0 /* parameter struct pt_regs * regs */
563 /*
564 * Page fault traps.
565 *
566 * If the real exception handler (from hw_exception_handler.S) didn't find
567 * the mapping for the process, then we're thrown here to handle such situation.
568 *
569 * Trap entered via exceptions, so EE bit is set, and interrupts
570 * are masked. This is nice, means we don't have to CLI before state save
571 *
572 * Build a standard exception frame for TLB Access errors. All TLB exceptions
573 * will bail out to this point if they can't resolve the lightweight TLB fault.
574 *
575 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
576 * void do_page_fault(struct pt_regs *regs,
577 * unsigned long address,
578 * unsigned long error_code)
579 */
580 /* data and intruction trap - which is choose is resolved int fault.c */
581 C_ENTRY(page_fault_data_trap):
582 SAVE_STATE /* Save registers.*/
583 /* PC, before IRQ/trap - this is one instruction above */
584 swi r17, r1, PT_PC;
585 tovirt(r1,r1)
586 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
587 addik r15, r0, ret_from_exc-8
588 mfs r6, rear /* parameter unsigned long address */
589 mfs r7, resr /* parameter unsigned long error_code */
590 rted r0, do_page_fault
591 addik r5, r1, 0 /* parameter struct pt_regs * regs */
593 C_ENTRY(page_fault_instr_trap):
594 SAVE_STATE /* Save registers.*/
595 /* PC, before IRQ/trap - this is one instruction above */
596 swi r17, r1, PT_PC;
597 tovirt(r1,r1)
598 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
599 addik r15, r0, ret_from_exc-8
600 mfs r6, rear /* parameter unsigned long address */
601 ori r7, r0, 0 /* parameter unsigned long error_code */
602 rted r0, do_page_fault
603 addik r5, r1, 0 /* parameter struct pt_regs * regs */
605 /* Entry point used to return from an exception. */
606 C_ENTRY(ret_from_exc):
607 lwi r11, r1, PT_MODE;
608 bnei r11, 2f; /* See if returning to kernel mode, */
609 /* ... if so, skip resched &c. */
611 /* We're returning to user mode, so check for various conditions that
612 trigger rescheduling. */
613 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
614 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
615 andi r11, r11, _TIF_NEED_RESCHED;
616 beqi r11, 5f;
618 /* Call the scheduler before returning from a syscall/trap. */
619 bralid r15, schedule; /* Call scheduler */
620 nop; /* delay slot */
622 /* Maybe handle a signal */
623 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
624 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
625 andi r11, r11, _TIF_SIGPENDING;
626 beqi r11, 1f; /* Signals to handle, handle them */
628 /*
629 * Handle a signal return; Pending signals should be in r18.
630 *
631 * Not all registers are saved by the normal trap/interrupt entry
632 * points (for instance, call-saved registers (because the normal
633 * C-compiler calling sequence in the kernel makes sure they're
634 * preserved), and call-clobbered registers in the case of
635 * traps), but signal handlers may want to examine or change the
636 * complete register state. Here we save anything not saved by
637 * the normal entry sequence, so that it may be safely restored
638 * (in a possibly modified form) after do_signal returns. */
639 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
640 addi r7, r0, 0; /* Arg 3: int in_syscall */
641 bralid r15, do_signal; /* Handle any signals */
642 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
644 /* Finally, return to user state. */
645 1: set_bip; /* Ints masked for state restore */
646 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
647 VM_OFF;
648 tophys(r1,r1);
650 RESTORE_REGS;
651 addik r1, r1, PT_SIZE /* Clean up stack space. */
653 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
654 bri 6f;
655 /* Return to kernel state. */
656 2: set_bip; /* Ints masked for state restore */
657 VM_OFF;
658 tophys(r1,r1);
659 RESTORE_REGS;
660 addik r1, r1, PT_SIZE /* Clean up stack space. */
662 tovirt(r1,r1);
663 6:
664 EXC_return: /* Make global symbol for debugging */
665 rtbd r14, 0; /* Instructions to return from an IRQ */
666 nop;
668 /*
669 * HW EXCEPTION rutine end
670 */
672 /*
673 * Hardware maskable interrupts.
674 *
675 * The stack-pointer (r1) should have already been saved to the memory
676 * location PER_CPU(ENTRY_SP).
677 */
678 C_ENTRY(_interrupt):
679 /* MS: we are in physical address */
680 /* Save registers, switch to proper stack, convert SP to virtual.*/
681 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
682 /* MS: See if already in kernel mode. */
683 mfs r1, rmsr
684 nop
685 andi r1, r1, MSR_UMS
686 bnei r1, 1f
688 /* Kernel-mode state save. */
689 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
690 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
691 /* save registers */
692 /* MS: Make room on the stack -> activation record */
693 addik r1, r1, -PT_SIZE;
694 SAVE_REGS
695 brid 2f;
696 swi r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */
697 1:
698 /* User-mode state save. */
699 /* MS: get the saved current */
700 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
701 tophys(r1,r1);
702 lwi r1, r1, TS_THREAD_INFO;
703 addik r1, r1, THREAD_SIZE;
704 tophys(r1,r1);
705 /* save registers */
706 addik r1, r1, -PT_SIZE;
707 SAVE_REGS
708 /* calculate mode */
709 swi r0, r1, PT_MODE;
710 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
711 swi r11, r1, PT_R1;
712 clear_ums;
713 2:
714 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
715 tovirt(r1,r1)
716 addik r15, r0, irq_call;
717 irq_call:rtbd r0, do_IRQ;
718 addik r5, r1, 0;
720 /* MS: we are in virtual mode */
721 ret_from_irq:
722 lwi r11, r1, PT_MODE;
723 bnei r11, 2f;
725 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
726 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
727 andi r11, r11, _TIF_NEED_RESCHED;
728 beqi r11, 5f
729 bralid r15, schedule;
730 nop; /* delay slot */
732 /* Maybe handle a signal */
733 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
734 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
735 andi r11, r11, _TIF_SIGPENDING;
736 beqid r11, no_intr_resched
737 /* Handle a signal return; Pending signals should be in r18. */
738 addi r7, r0, 0; /* Arg 3: int in_syscall */
739 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
740 bralid r15, do_signal; /* Handle any signals */
741 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
743 /* Finally, return to user state. */
744 no_intr_resched:
745 /* Disable interrupts, we are now committed to the state restore */
746 disable_irq
747 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
748 VM_OFF;
749 tophys(r1,r1);
750 RESTORE_REGS
751 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
752 lwi r1, r1, PT_R1 - PT_SIZE;
753 bri 6f;
754 /* MS: Return to kernel state. */
755 2:
756 #ifdef CONFIG_PREEMPT
757 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
758 /* MS: get preempt_count from thread info */
759 lwi r5, r11, TI_PREEMPT_COUNT;
760 bgti r5, restore;
762 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
763 andi r5, r5, _TIF_NEED_RESCHED;
764 beqi r5, restore /* if zero jump over */
766 preempt:
767 /* interrupts are off that's why I am calling preempt_chedule_irq */
768 bralid r15, preempt_schedule_irq
769 nop
770 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
771 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
772 andi r5, r5, _TIF_NEED_RESCHED;
773 bnei r5, preempt /* if non zero jump to resched */
774 restore:
775 #endif
776 VM_OFF /* MS: turn off MMU */
777 tophys(r1,r1)
778 RESTORE_REGS
779 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
780 tovirt(r1,r1);
781 6:
782 IRQ_return: /* MS: Make global symbol for debugging */
783 rtid r14, 0
784 nop
786 /*
787 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
788 * and call handling function with saved pt_regs
789 */
790 C_ENTRY(_debug_exception):
791 /* BIP bit is set on entry, no interrupts can occur */
792 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
794 mfs r1, rmsr
795 nop
796 andi r1, r1, MSR_UMS
797 bnei r1, 1f
798 /* MS: Kernel-mode state save - kgdb */
799 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
801 /* BIP bit is set on entry, no interrupts can occur */
802 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE;
803 SAVE_REGS;
804 /* save all regs to pt_reg structure */
805 swi r0, r1, PT_R0; /* R0 must be saved too */
806 swi r14, r1, PT_R14 /* rewrite saved R14 value */
807 swi r16, r1, PT_PC; /* PC and r16 are the same */
808 /* save special purpose registers to pt_regs */
809 mfs r11, rear;
810 swi r11, r1, PT_EAR;
811 mfs r11, resr;
812 swi r11, r1, PT_ESR;
813 mfs r11, rfsr;
814 swi r11, r1, PT_FSR;
816 /* stack pointer is in physical address at it is decrease
817 * by PT_SIZE but we need to get correct R1 value */
818 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE;
819 swi r11, r1, PT_R1
820 /* MS: r31 - current pointer isn't changed */
821 tovirt(r1,r1)
822 #ifdef CONFIG_KGDB
823 addi r5, r1, 0 /* pass pt_reg address as the first arg */
824 la r15, r0, dbtrap_call; /* return address */
825 rtbd r0, microblaze_kgdb_break
826 nop;
827 #endif
828 /* MS: Place handler for brki from kernel space if KGDB is OFF.
829 * It is very unlikely that another brki instruction is called. */
830 bri 0
832 /* MS: User-mode state save - gdb */
833 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
834 tophys(r1,r1);
835 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
836 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
837 tophys(r1,r1);
839 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
840 SAVE_REGS;
841 swi r16, r1, PT_PC; /* Save LP */
842 swi r0, r1, PT_MODE; /* Was in user-mode. */
843 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
844 swi r11, r1, PT_R1; /* Store user SP. */
845 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
846 tovirt(r1,r1)
847 set_vms;
848 addik r5, r1, 0;
849 addik r15, r0, dbtrap_call;
850 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
851 rtbd r0, sw_exception
852 nop
854 /* MS: The first instruction for the second part of the gdb/kgdb */
855 set_bip; /* Ints masked for state restore */
856 lwi r11, r1, PT_MODE;
857 bnei r11, 2f;
858 /* MS: Return to user space - gdb */
859 /* Get current task ptr into r11 */
860 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
861 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
862 andi r11, r11, _TIF_NEED_RESCHED;
863 beqi r11, 5f;
865 /* Call the scheduler before returning from a syscall/trap. */
866 bralid r15, schedule; /* Call scheduler */
867 nop; /* delay slot */
869 /* Maybe handle a signal */
870 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
871 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
872 andi r11, r11, _TIF_SIGPENDING;
873 beqi r11, 1f; /* Signals to handle, handle them */
875 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
876 addi r7, r0, 0; /* Arg 3: int in_syscall */
877 bralid r15, do_signal; /* Handle any signals */
878 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
880 /* Finally, return to user state. */
881 1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
882 VM_OFF;
883 tophys(r1,r1);
884 /* MS: Restore all regs */
885 RESTORE_REGS
886 addik r1, r1, PT_SIZE /* Clean up stack space */
887 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
888 DBTRAP_return_user: /* MS: Make global symbol for debugging */
889 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
890 nop;
892 /* MS: Return to kernel state - kgdb */
893 2: VM_OFF;
894 tophys(r1,r1);
895 /* MS: Restore all regs */
896 RESTORE_REGS
897 lwi r14, r1, PT_R14;
898 lwi r16, r1, PT_PC;
899 addik r1, r1, PT_SIZE; /* MS: Clean up stack space */
900 tovirt(r1,r1);
901 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
902 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
903 nop;
906 ENTRY(_switch_to)
907 /* prepare return value */
908 addk r3, r0, CURRENT_TASK
910 /* save registers in cpu_context */
911 /* use r11 and r12, volatile registers, as temp register */
912 /* give start of cpu_context for previous process */
913 addik r11, r5, TI_CPU_CONTEXT
914 swi r1, r11, CC_R1
915 swi r2, r11, CC_R2
916 /* skip volatile registers.
917 * they are saved on stack when we jumped to _switch_to() */
918 /* dedicated registers */
919 swi r13, r11, CC_R13
920 swi r14, r11, CC_R14
921 swi r15, r11, CC_R15
922 swi r16, r11, CC_R16
923 swi r17, r11, CC_R17
924 swi r18, r11, CC_R18
925 /* save non-volatile registers */
926 swi r19, r11, CC_R19
927 swi r20, r11, CC_R20
928 swi r21, r11, CC_R21
929 swi r22, r11, CC_R22
930 swi r23, r11, CC_R23
931 swi r24, r11, CC_R24
932 swi r25, r11, CC_R25
933 swi r26, r11, CC_R26
934 swi r27, r11, CC_R27
935 swi r28, r11, CC_R28
936 swi r29, r11, CC_R29
937 swi r30, r11, CC_R30
938 /* special purpose registers */
939 mfs r12, rmsr
940 swi r12, r11, CC_MSR
941 mfs r12, rear
942 swi r12, r11, CC_EAR
943 mfs r12, resr
944 swi r12, r11, CC_ESR
945 mfs r12, rfsr
946 swi r12, r11, CC_FSR
948 /* update r31, the current-give me pointer to task which will be next */
949 lwi CURRENT_TASK, r6, TI_TASK
950 /* stored it to current_save too */
951 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
953 /* get new process' cpu context and restore */
954 /* give me start where start context of next task */
955 addik r11, r6, TI_CPU_CONTEXT
957 /* non-volatile registers */
958 lwi r30, r11, CC_R30
959 lwi r29, r11, CC_R29
960 lwi r28, r11, CC_R28
961 lwi r27, r11, CC_R27
962 lwi r26, r11, CC_R26
963 lwi r25, r11, CC_R25
964 lwi r24, r11, CC_R24
965 lwi r23, r11, CC_R23
966 lwi r22, r11, CC_R22
967 lwi r21, r11, CC_R21
968 lwi r20, r11, CC_R20
969 lwi r19, r11, CC_R19
970 /* dedicated registers */
971 lwi r18, r11, CC_R18
972 lwi r17, r11, CC_R17
973 lwi r16, r11, CC_R16
974 lwi r15, r11, CC_R15
975 lwi r14, r11, CC_R14
976 lwi r13, r11, CC_R13
977 /* skip volatile registers */
978 lwi r2, r11, CC_R2
979 lwi r1, r11, CC_R1
981 /* special purpose registers */
982 lwi r12, r11, CC_FSR
983 mts rfsr, r12
984 lwi r12, r11, CC_MSR
985 mts rmsr, r12
987 rtsd r15, 8
988 nop
990 ENTRY(_reset)
991 brai 0x70; /* Jump back to FS-boot */
993 /* These are compiled and loaded into high memory, then
994 * copied into place in mach_early_setup */
995 .section .init.ivt, "ax"
996 .org 0x0
997 /* this is very important - here is the reset vector */
998 /* in current MMU branch you don't care what is here - it is
999 * used from bootloader site - but this is correct for FS-BOOT */
1000 brai 0x70
1001 nop
1002 brai TOPHYS(_user_exception); /* syscall handler */
1003 brai TOPHYS(_interrupt); /* Interrupt handler */
1004 brai TOPHYS(_debug_exception); /* debug trap handler */
1005 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
1007 .section .rodata,"a"
1008 #include "syscall_table.S"
1010 syscall_table_size=(.-sys_call_table)
1012 type_SYSCALL:
1013 .ascii "SYSCALL\0"
1014 type_IRQ:
1015 .ascii "IRQ\0"
1016 type_IRQ_PREEMPT:
1017 .ascii "IRQ (PREEMPTED)\0"
1018 type_SYSCALL_PREEMPT:
1019 .ascii " SYSCALL (PREEMPTED)\0"
1021 /*
1022 * Trap decoding for stack unwinder
1023 * Tuples are (start addr, end addr, string)
1024 * If return address lies on [start addr, end addr],
1025 * unwinder displays 'string'
1026 */
1028 .align 4
1029 .global microblaze_trap_handlers
1030 microblaze_trap_handlers:
1031 /* Exact matches come first */
1032 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
1033 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
1034 /* Fuzzy matches go here */
1035 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
1036 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1037 /* End of table */
1038 .word 0 ; .word 0 ; .word 0