2 * Low-level system-call handling, trap handlers and context-switching
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>
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.
14 * Written by Miles Bader <miles@gnu.org>
15 * Heavily modified by John Williams for Microblaze
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>
29 #include <asm/unistd.h>
31 #include <linux/errno.h>
32 #include <asm/signal.h>
36 /* The size of a state save frame. */
37 #define STATE_SAVE_SIZE (PT_SIZE + STATE_SAVE_ARG_SPACE)
39 /* The offset of the struct pt_regs in a `state save frame' on the stack. */
40 #define PTO STATE_SAVE_ARG_SPACE /* 24 the space for args */
42 #define C_ENTRY(name) .globl name; .align 4; name
45 * Various ways of setting and clearing BIP in flags reg.
46 * This is mucky, but necessary using microblaze version that
47 * allows msr ops to write to BIP
49 #if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR
95 msrclr r11, MSR_VMS | MSR_UMS
102 andi r11, r11, ~MSR_BIP
110 ori r11, r11, MSR_BIP
118 andi r11, r11, ~MSR_EIP
134 andi r11, r11, ~MSR_IE
150 ori r11, r11, MSR_VMS
151 andni r11, r11, MSR_UMS
159 ori r11, r11, MSR_VMS
160 andni r11, r11, MSR_UMS
168 andni r11, r11, (MSR_VMS|MSR_UMS)
174 /* Define how to call high-level functions. With MMU, virtual mode must be
175 * enabled when calling the high-level function. Clobbers R11.
176 * VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL
179 /* turn on virtual protected mode save */
186 /* turn off virtual protected mode save and user mode save*/
189 rted r0, TOPHYS(1f); \
194 swi r2, r1, PTO+PT_R2; /* Save SDA */ \
195 swi r3, r1, PTO+PT_R3; \
196 swi r4, r1, PTO+PT_R4; \
197 swi r5, r1, PTO+PT_R5; \
198 swi r6, r1, PTO+PT_R6; \
199 swi r7, r1, PTO+PT_R7; \
200 swi r8, r1, PTO+PT_R8; \
201 swi r9, r1, PTO+PT_R9; \
202 swi r10, r1, PTO+PT_R10; \
203 swi r11, r1, PTO+PT_R11; /* save clobbered regs after rval */\
204 swi r12, r1, PTO+PT_R12; \
205 swi r13, r1, PTO+PT_R13; /* Save SDA2 */ \
206 swi r14, r1, PTO+PT_PC; /* PC, before IRQ/trap */ \
207 swi r15, r1, PTO+PT_R15; /* Save LP */ \
208 swi r18, r1, PTO+PT_R18; /* Save asm scratch reg */ \
209 swi r19, r1, PTO+PT_R19; \
210 swi r20, r1, PTO+PT_R20; \
211 swi r21, r1, PTO+PT_R21; \
212 swi r22, r1, PTO+PT_R22; \
213 swi r23, r1, PTO+PT_R23; \
214 swi r24, r1, PTO+PT_R24; \
215 swi r25, r1, PTO+PT_R25; \
216 swi r26, r1, PTO+PT_R26; \
217 swi r27, r1, PTO+PT_R27; \
218 swi r28, r1, PTO+PT_R28; \
219 swi r29, r1, PTO+PT_R29; \
220 swi r30, r1, PTO+PT_R30; \
221 swi r31, r1, PTO+PT_R31; /* Save current task reg */ \
222 mfs r11, rmsr; /* save MSR */ \
224 swi r11, r1, PTO+PT_MSR;
226 #define RESTORE_REGS \
227 lwi r11, r1, PTO+PT_MSR; \
230 lwi r2, r1, PTO+PT_R2; /* restore SDA */ \
231 lwi r3, r1, PTO+PT_R3; \
232 lwi r4, r1, PTO+PT_R4; \
233 lwi r5, r1, PTO+PT_R5; \
234 lwi r6, r1, PTO+PT_R6; \
235 lwi r7, r1, PTO+PT_R7; \
236 lwi r8, r1, PTO+PT_R8; \
237 lwi r9, r1, PTO+PT_R9; \
238 lwi r10, r1, PTO+PT_R10; \
239 lwi r11, r1, PTO+PT_R11; /* restore clobbered regs after rval */\
240 lwi r12, r1, PTO+PT_R12; \
241 lwi r13, r1, PTO+PT_R13; /* restore SDA2 */ \
242 lwi r14, r1, PTO+PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
243 lwi r15, r1, PTO+PT_R15; /* restore LP */ \
244 lwi r18, r1, PTO+PT_R18; /* restore asm scratch reg */ \
245 lwi r19, r1, PTO+PT_R19; \
246 lwi r20, r1, PTO+PT_R20; \
247 lwi r21, r1, PTO+PT_R21; \
248 lwi r22, r1, PTO+PT_R22; \
249 lwi r23, r1, PTO+PT_R23; \
250 lwi r24, r1, PTO+PT_R24; \
251 lwi r25, r1, PTO+PT_R25; \
252 lwi r26, r1, PTO+PT_R26; \
253 lwi r27, r1, PTO+PT_R27; \
254 lwi r28, r1, PTO+PT_R28; \
255 lwi r29, r1, PTO+PT_R29; \
256 lwi r30, r1, PTO+PT_R30; \
257 lwi r31, r1, PTO+PT_R31; /* Restore cur task reg */
264 * System calls are handled here.
267 * Syscall number in r12, args in r5-r10
270 * Trap entered via brki instruction, so BIP bit is set, and interrupts
271 * are masked. This is nice, means we don't have to CLI before state save
273 C_ENTRY(_user_exception):
274 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
275 addi r14, r14, 4 /* return address is 4 byte after call */
276 swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */
278 lwi r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/
279 beqi r11, 1f; /* Jump ahead if coming from user */
280 /* Kernel-mode state save. */
281 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
283 swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */
284 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
286 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
289 addi r11, r0, 1; /* Was in kernel-mode. */
290 swi r11, r1, PTO+PT_MODE; /* pt_regs -> kernel mode */
292 nop; /* Fill delay slot */
294 /* User-mode state save. */
296 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
297 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
299 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
300 /* calculate kernel stack pointer from task struct 8k */
301 addik r1, r1, THREAD_SIZE;
304 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
307 swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */
308 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
309 swi r11, r1, PTO+PT_R1; /* Store user SP. */
311 swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode. */
312 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
313 /* Save away the syscall number. */
314 swi r12, r1, PTO+PT_R0;
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.
329 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
330 lwi r11, r11, TI_FLAGS /* get flags in thread info */
331 andi r11, r11, _TIF_WORK_SYSCALL_MASK
334 addik r3, r0, -ENOSYS
335 swi r3, r1, PTO + PT_R3
336 brlid r15, do_syscall_trace_enter
337 addik r5, r1, PTO + PT_R0
339 # do_syscall_trace_enter returns the new syscall nr.
341 lwi r5, r1, PTO+PT_R5;
342 lwi r6, r1, PTO+PT_R6;
343 lwi r7, r1, PTO+PT_R7;
344 lwi r8, r1, PTO+PT_R8;
345 lwi r9, r1, PTO+PT_R9;
346 lwi r10, r1, PTO+PT_R10;
348 /* Jump to the appropriate function for the system call number in r12
349 * (r12 is not preserved), or return an error if r12 is not valid.
350 * The LP register should point to the location where the called function
351 * should return. [note that MAKE_SYS_CALL uses label 1] */
352 /* See if the system call number is valid */
353 addi r11, r12, -__NR_syscalls;
355 /* Figure out which function to use for this system call. */
356 /* Note Microblaze barrel shift is optional, so don't rely on it */
357 add r12, r12, r12; /* convert num -> ptr */
361 /* Trac syscalls and stored them to r0_ram */
362 lwi r3, r12, 0x400 + r0_ram
364 swi r3, r12, 0x400 + r0_ram
367 # Find and jump into the syscall handler.
368 lwi r12, r12, sys_call_table
369 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
370 la r15, r0, ret_from_trap-8
373 /* The syscall number is invalid, return an error. */
375 addi r3, r0, -ENOSYS;
376 rtsd r15,8; /* looks like a normal subroutine return */
380 /* Entry point used to return from a syscall/trap */
381 /* We re-enable BIP bit before state restore */
382 C_ENTRY(ret_from_trap):
383 set_bip; /* Ints masked for state restore*/
384 swi r3, r1, PTO + PT_R3
385 swi r4, r1, PTO + PT_R4
387 lwi r11, r1, PTO+PT_MODE;
388 /* See if returning to kernel mode, if so, skip resched &c. */
390 /* We're returning to user mode, so check for various conditions that
391 * trigger rescheduling. */
392 /* FIXME: Restructure all these flag checks. */
393 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
394 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
395 andi r11, r11, _TIF_WORK_SYSCALL_MASK
398 brlid r15, do_syscall_trace_leave
399 addik r5, r1, PTO + PT_R0
401 /* We're returning to user mode, so check for various conditions that
402 * trigger rescheduling. */
403 /* get thread info from current task */
404 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
405 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
406 andi r11, r11, _TIF_NEED_RESCHED;
409 bralid r15, schedule; /* Call scheduler */
410 nop; /* delay slot */
412 /* Maybe handle a signal */
413 5: /* get thread info from current task*/
414 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
415 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
416 andi r11, r11, _TIF_SIGPENDING;
417 beqi r11, 1f; /* Signals to handle, handle them */
419 la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
420 addi r7, r0, 1; /* Arg 3: int in_syscall */
421 bralid r15, do_signal; /* Handle any signals */
422 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
424 /* Finally, return to user state. */
426 swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
427 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
431 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
432 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
435 /* Return to kernel state. */
439 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
442 TRAP_return: /* Make global symbol for debugging */
443 rtbd r14, 0; /* Instructions to return from an IRQ */
447 /* These syscalls need access to the struct pt_regs on the stack, so we
448 implement them in assembly (they're basically all wrappers anyway). */
450 C_ENTRY(sys_fork_wrapper):
451 addi r5, r0, SIGCHLD /* Arg 0: flags */
452 lwi r6, r1, PTO+PT_R1 /* Arg 1: child SP (use parent's) */
453 la r7, r1, PTO /* Arg 2: parent context */
454 add r8. r0, r0 /* Arg 3: (unused) */
455 add r9, r0, r0; /* Arg 4: (unused) */
456 add r10, r0, r0; /* Arg 5: (unused) */
457 brid do_fork /* Do real work (tail-call) */
460 /* This the initial entry point for a new child thread, with an appropriate
461 stack in place that makes it look the the child is in the middle of an
462 syscall. This function is actually `returned to' from switch_thread
463 (copy_thread makes ret_from_fork the return address in each new thread's
465 C_ENTRY(ret_from_fork):
466 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
467 add r3, r5, r0; /* switch_thread returns the prev task */
468 /* ( in the delay slot ) */
469 add r3, r0, r0; /* Child's fork call should return 0. */
470 brid ret_from_trap; /* Do normal trap return */
474 brid microblaze_vfork /* Do real work (tail-call) */
478 bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
479 lwi r6, r1, PTO + PT_R1; /* If so, use paret's stack ptr */
480 1: add r10, r0, r9; /* Arg 6: (child_tidptr) */
481 add r9, r0, r8; /* Arg 5: (parent_tidptr) */
482 add r8, r0, r7; /* Arg 4: (stack_size) */
483 la r7, r1, PTO; /* Arg 3: pt_regs */
484 brid do_fork /* Do real work (tail-call) */
488 la r8, r1, PTO; /* add user context as 4th arg */
489 brid microblaze_execve; /* Do real work (tail-call).*/
492 C_ENTRY(sys_rt_sigreturn_wrapper):
493 swi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
494 swi r4, r1, PTO+PT_R4;
495 la r5, r1, PTO; /* add user context as 1st arg */
496 brlid r15, sys_rt_sigreturn /* Do real work */
498 lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
499 lwi r4, r1, PTO+PT_R4;
500 bri ret_from_trap /* fall through will not work here due to align */
504 * HW EXCEPTION rutine start
508 swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */ \
509 set_bip; /*equalize initial state for all possible entries*/\
513 /* See if already in kernel mode.*/ \
514 lwi r11, r0, TOPHYS(PER_CPU(KM)); \
515 beqi r11, 1f; /* Jump ahead if coming from user */\
516 /* Kernel-mode state save. */ \
517 /* Reload kernel stack-ptr. */ \
518 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
520 swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */ \
521 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */\
522 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */\
524 /* PC, before IRQ/trap - this is one instruction above */ \
525 swi r17, r1, PTO+PT_PC; \
527 addi r11, r0, 1; /* Was in kernel-mode. */ \
528 swi r11, r1, PTO+PT_MODE; \
530 nop; /* Fill delay slot */ \
531 1: /* User-mode state save. */ \
532 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */\
533 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
535 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
536 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */\
539 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */\
541 /* PC, before IRQ/trap - this is one instruction above FIXME*/ \
542 swi r17, r1, PTO+PT_PC; \
544 swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */ \
545 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
546 swi r11, r1, PTO+PT_R1; /* Store user SP. */ \
548 swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode.*/\
549 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); \
550 /* Save away the syscall number. */ \
551 swi r0, r1, PTO+PT_R0; \
554 C_ENTRY(full_exception_trap):
555 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
556 /* adjust exception address for privileged instruction
557 * for finding where is it */
559 SAVE_STATE /* Save registers */
560 /* FIXME this can be store directly in PT_ESR reg.
561 * I tested it but there is a fault */
562 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
563 la r15, r0, ret_from_exc - 8
564 la r5, r1, PTO /* parameter struct pt_regs * regs */
567 mfs r7, rfsr; /* save FSR */
569 mts rfsr, r0; /* Clear sticky fsr */
571 la r12, r0, full_exception
577 * Unaligned data trap.
579 * Unaligned data trap last on 4k page is handled here.
581 * Trap entered via exception, so EE bit is set, and interrupts
582 * are masked. This is nice, means we don't have to CLI before state save
584 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
586 C_ENTRY(unaligned_data_trap):
587 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
588 SAVE_STATE /* Save registers.*/
589 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
590 la r15, r0, ret_from_exc-8
591 mfs r3, resr /* ESR */
593 mfs r4, rear /* EAR */
595 la r7, r1, PTO /* parameter struct pt_regs * regs */
596 la r12, r0, _unaligned_data_exception
598 rtbd r12, 0; /* interrupts enabled */
604 * If the real exception handler (from hw_exception_handler.S) didn't find
605 * the mapping for the process, then we're thrown here to handle such situation.
607 * Trap entered via exceptions, so EE bit is set, and interrupts
608 * are masked. This is nice, means we don't have to CLI before state save
610 * Build a standard exception frame for TLB Access errors. All TLB exceptions
611 * will bail out to this point if they can't resolve the lightweight TLB fault.
613 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
614 * void do_page_fault(struct pt_regs *regs,
615 * unsigned long address,
616 * unsigned long error_code)
618 /* data and intruction trap - which is choose is resolved int fault.c */
619 C_ENTRY(page_fault_data_trap):
620 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
621 SAVE_STATE /* Save registers.*/
622 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
623 la r15, r0, ret_from_exc-8
624 la r5, r1, PTO /* parameter struct pt_regs * regs */
625 mfs r6, rear /* parameter unsigned long address */
627 mfs r7, resr /* parameter unsigned long error_code */
629 la r12, r0, do_page_fault
631 rtbd r12, 0; /* interrupts enabled */
634 C_ENTRY(page_fault_instr_trap):
635 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
636 SAVE_STATE /* Save registers.*/
637 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
638 la r15, r0, ret_from_exc-8
639 la r5, r1, PTO /* parameter struct pt_regs * regs */
640 mfs r6, rear /* parameter unsigned long address */
642 ori r7, r0, 0 /* parameter unsigned long error_code */
643 la r12, r0, do_page_fault
645 rtbd r12, 0; /* interrupts enabled */
648 /* Entry point used to return from an exception. */
649 C_ENTRY(ret_from_exc):
650 set_bip; /* Ints masked for state restore*/
651 lwi r11, r1, PTO+PT_MODE;
652 bnei r11, 2f; /* See if returning to kernel mode, */
653 /* ... if so, skip resched &c. */
655 /* We're returning to user mode, so check for various conditions that
656 trigger rescheduling. */
657 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
658 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
659 andi r11, r11, _TIF_NEED_RESCHED;
662 /* Call the scheduler before returning from a syscall/trap. */
663 bralid r15, schedule; /* Call scheduler */
664 nop; /* delay slot */
666 /* Maybe handle a signal */
667 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
668 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
669 andi r11, r11, _TIF_SIGPENDING;
670 beqi r11, 1f; /* Signals to handle, handle them */
673 * Handle a signal return; Pending signals should be in r18.
675 * Not all registers are saved by the normal trap/interrupt entry
676 * points (for instance, call-saved registers (because the normal
677 * C-compiler calling sequence in the kernel makes sure they're
678 * preserved), and call-clobbered registers in the case of
679 * traps), but signal handlers may want to examine or change the
680 * complete register state. Here we save anything not saved by
681 * the normal entry sequence, so that it may be safely restored
682 * (in a possibly modified form) after do_signal returns. */
683 la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
684 addi r7, r0, 0; /* Arg 3: int in_syscall */
685 bralid r15, do_signal; /* Handle any signals */
686 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
688 /* Finally, return to user state. */
689 1: swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
690 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
695 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
697 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
699 /* Return to kernel state. */
703 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
707 EXC_return: /* Make global symbol for debugging */
708 rtbd r14, 0; /* Instructions to return from an IRQ */
712 * HW EXCEPTION rutine end
716 * Hardware maskable interrupts.
718 * The stack-pointer (r1) should have already been saved to the memory
719 * location PER_CPU(ENTRY_SP).
722 /* MS: we are in physical address */
723 /* Save registers, switch to proper stack, convert SP to virtual.*/
724 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
725 swi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
726 /* MS: See if already in kernel mode. */
727 lwi r11, r0, TOPHYS(PER_CPU(KM));
728 beqi r11, 1f; /* MS: Jump ahead if coming from user */
730 /* Kernel-mode state save. */
732 tophys(r1,r11); /* MS: I have in r1 physical address where stack is */
733 /* MS: Save original SP - position PT_R1 to next stack frame 4 *1 - 152*/
734 swi r11, r1, (PT_R1 - PT_SIZE);
735 /* MS: restore r11 because of saving in SAVE_REGS */
736 lwi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
738 /* MS: Make room on the stack -> activation record */
739 addik r1, r1, -STATE_SAVE_SIZE;
742 addi r11, r0, 1; /* MS: Was in kernel-mode. */
743 swi r11, r1, PTO + PT_MODE; /* MS: and save it */
745 nop; /* MS: Fill delay slot */
748 /* User-mode state save. */
749 /* MS: restore r11 -> FIXME move before SAVE_REG */
750 lwi r11, r0, TOPHYS(PER_CPU(R11_SAVE));
751 /* MS: get the saved current */
752 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
754 lwi r1, r1, TS_THREAD_INFO;
755 addik r1, r1, THREAD_SIZE;
758 addik r1, r1, -STATE_SAVE_SIZE;
761 swi r0, r1, PTO + PT_MODE;
762 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
763 swi r11, r1, PTO+PT_R1;
764 /* setup kernel mode to KM */
766 swi r11, r0, TOPHYS(PER_CPU(KM));
769 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
770 swi r0, r1, PTO + PT_R0;
775 la r15, r0, irq_call;
776 irq_call:rtbd r11, 0;
779 /* MS: we are in virtual mode */
781 lwi r11, r1, PTO + PT_MODE;
784 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
785 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
786 andi r11, r11, _TIF_NEED_RESCHED;
788 bralid r15, schedule;
789 nop; /* delay slot */
791 /* Maybe handle a signal */
792 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
793 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
794 andi r11, r11, _TIF_SIGPENDING;
795 beqid r11, no_intr_resched
796 /* Handle a signal return; Pending signals should be in r18. */
797 addi r7, r0, 0; /* Arg 3: int in_syscall */
798 la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
799 bralid r15, do_signal; /* Handle any signals */
800 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
802 /* Finally, return to user state. */
804 /* Disable interrupts, we are now committed to the state restore */
806 swi r0, r0, PER_CPU(KM); /* MS: Now officially in user state. */
807 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
811 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
812 lwi r1, r1, PT_R1 - PT_SIZE;
814 /* MS: Return to kernel state. */
816 #ifdef CONFIG_PREEMPT
817 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
818 /* MS: get preempt_count from thread info */
819 lwi r5, r11, TI_PREEMPT_COUNT;
822 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
823 andi r5, r5, _TIF_NEED_RESCHED;
824 beqi r5, restore /* if zero jump over */
827 /* interrupts are off that's why I am calling preempt_chedule_irq */
828 bralid r15, preempt_schedule_irq
830 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
831 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
832 andi r5, r5, _TIF_NEED_RESCHED;
833 bnei r5, preempt /* if non zero jump to resched */
836 VM_OFF /* MS: turn off MMU */
839 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
842 IRQ_return: /* MS: Make global symbol for debugging */
848 * We enter dbtrap in "BIP" (breakpoint) mode.
849 * So we exit the breakpoint mode with an 'rtbd' and proceed with the
851 * however, wait to save state first
853 C_ENTRY(_debug_exception):
854 /* BIP bit is set on entry, no interrupts can occur */
855 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
857 swi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* Save r11 */
858 set_bip; /*equalize initial state for all possible entries*/
861 lwi r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/
862 beqi r11, 1f; /* Jump ahead if coming from user */
863 /* Kernel-mode state save. */
864 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
866 swi r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */
867 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
869 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
872 addi r11, r0, 1; /* Was in kernel-mode. */
873 swi r11, r1, PTO + PT_MODE;
875 nop; /* Fill delay slot */
876 1: /* User-mode state save. */
877 lwi r11, r0, TOPHYS(r0_ram + PTO + PT_R11); /* restore r11 */
878 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
880 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
881 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
884 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
887 swi r0, r1, PTO+PT_MODE; /* Was in user-mode. */
888 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
889 swi r11, r1, PTO+PT_R1; /* Store user SP. */
891 swi r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode. */
892 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
893 /* Save away the syscall number. */
894 swi r0, r1, PTO+PT_R0;
897 addi r5, r0, SIGTRAP /* send the trap signal */
898 add r6, r0, CURRENT_TASK; /* Get current task ptr into r11 */
899 addk r7, r0, r0 /* 3rd param zero */
902 la r11, r0, send_sig;
903 la r15, r0, dbtrap_call;
904 dbtrap_call: rtbd r11, 0;
907 set_bip; /* Ints masked for state restore*/
908 lwi r11, r1, PTO+PT_MODE;
911 /* Get current task ptr into r11 */
912 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
913 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
914 andi r11, r11, _TIF_NEED_RESCHED;
917 /* Call the scheduler before returning from a syscall/trap. */
919 bralid r15, schedule; /* Call scheduler */
920 nop; /* delay slot */
921 /* XXX Is PT_DTRACE handling needed here? */
922 /* XXX m68knommu also checks TASK_STATE & TASK_COUNTER here. */
924 /* Maybe handle a signal */
925 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
926 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
927 andi r11, r11, _TIF_SIGPENDING;
928 beqi r11, 1f; /* Signals to handle, handle them */
930 /* Handle a signal return; Pending signals should be in r18. */
931 /* Not all registers are saved by the normal trap/interrupt entry
932 points (for instance, call-saved registers (because the normal
933 C-compiler calling sequence in the kernel makes sure they're
934 preserved), and call-clobbered registers in the case of
935 traps), but signal handlers may want to examine or change the
936 complete register state. Here we save anything not saved by
937 the normal entry sequence, so that it may be safely restored
938 (in a possibly modified form) after do_signal returns. */
940 la r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
941 addi r7, r0, 0; /* Arg 3: int in_syscall */
942 bralid r15, do_signal; /* Handle any signals */
943 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
946 /* Finally, return to user state. */
947 1: swi r0, r0, PER_CPU(KM); /* Now officially in user state. */
948 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
953 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
956 lwi r1, r1, PT_R1 - PT_SIZE;
957 /* Restore user stack pointer. */
960 /* Return to kernel state. */
964 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
968 DBTRAP_return: /* Make global symbol for debugging */
969 rtbd r14, 0; /* Instructions to return from an IRQ */
975 /* prepare return value */
976 addk r3, r0, CURRENT_TASK
978 /* save registers in cpu_context */
979 /* use r11 and r12, volatile registers, as temp register */
980 /* give start of cpu_context for previous process */
981 addik r11, r5, TI_CPU_CONTEXT
984 /* skip volatile registers.
985 * they are saved on stack when we jumped to _switch_to() */
986 /* dedicated registers */
993 /* save non-volatile registers */
1000 swi r25, r11, CC_R25
1001 swi r26, r11, CC_R26
1002 swi r27, r11, CC_R27
1003 swi r28, r11, CC_R28
1004 swi r29, r11, CC_R29
1005 swi r30, r11, CC_R30
1006 /* special purpose registers */
1009 swi r12, r11, CC_MSR
1012 swi r12, r11, CC_EAR
1015 swi r12, r11, CC_ESR
1018 swi r12, r11, CC_FSR
1020 /* update r31, the current-give me pointer to task which will be next */
1021 lwi CURRENT_TASK, r6, TI_TASK
1022 /* stored it to current_save too */
1023 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
1025 /* get new process' cpu context and restore */
1026 /* give me start where start context of next task */
1027 addik r11, r6, TI_CPU_CONTEXT
1029 /* non-volatile registers */
1030 lwi r30, r11, CC_R30
1031 lwi r29, r11, CC_R29
1032 lwi r28, r11, CC_R28
1033 lwi r27, r11, CC_R27
1034 lwi r26, r11, CC_R26
1035 lwi r25, r11, CC_R25
1036 lwi r24, r11, CC_R24
1037 lwi r23, r11, CC_R23
1038 lwi r22, r11, CC_R22
1039 lwi r21, r11, CC_R21
1040 lwi r20, r11, CC_R20
1041 lwi r19, r11, CC_R19
1042 /* dedicated registers */
1043 lwi r18, r11, CC_R18
1044 lwi r17, r11, CC_R17
1045 lwi r16, r11, CC_R16
1046 lwi r15, r11, CC_R15
1047 lwi r14, r11, CC_R14
1048 lwi r13, r11, CC_R13
1049 /* skip volatile registers */
1053 /* special purpose registers */
1054 lwi r12, r11, CC_FSR
1057 lwi r12, r11, CC_MSR
1065 brai 0x70; /* Jump back to FS-boot */
1070 swi r5, r0, 0x250 + TOPHYS(r0_ram)
1073 swi r5, r0, 0x254 + TOPHYS(r0_ram)
1076 /* These are compiled and loaded into high memory, then
1077 * copied into place in mach_early_setup */
1078 .section .init.ivt, "ax"
1080 /* this is very important - here is the reset vector */
1081 /* in current MMU branch you don't care what is here - it is
1082 * used from bootloader site - but this is correct for FS-BOOT */
1085 brai TOPHYS(_user_exception); /* syscall handler */
1086 brai TOPHYS(_interrupt); /* Interrupt handler */
1087 brai TOPHYS(_break); /* nmi trap handler */
1088 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
1091 brai TOPHYS(_debug_exception); /* debug trap handler*/
1093 .section .rodata,"a"
1094 #include "syscall_table.S"
1096 syscall_table_size=(.-sys_call_table)
1103 .ascii "IRQ (PREEMPTED)\0"
1104 type_SYSCALL_PREEMPT:
1105 .ascii " SYSCALL (PREEMPTED)\0"
1108 * Trap decoding for stack unwinder
1109 * Tuples are (start addr, end addr, string)
1110 * If return address lies on [start addr, end addr],
1111 * unwinder displays 'string'
1115 .global microblaze_trap_handlers
1116 microblaze_trap_handlers:
1117 /* Exact matches come first */
1118 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
1119 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
1120 /* Fuzzy matches go here */
1121 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
1122 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1124 .word 0 ; .word 0 ; .word 0