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
89 msrclr r0, MSR_VMS | MSR_UMS
94 andi r11, r11, ~MSR_BIP
100 ori r11, r11, MSR_BIP
106 andi r11, r11, ~MSR_EIP
118 andi r11, r11, ~MSR_IE
130 ori r11, r11, MSR_VMS
131 andni r11, r11, MSR_UMS
137 ori r11, r11, MSR_VMS
138 andni r11, r11, MSR_UMS
144 andni r11, r11, MSR_UMS
150 andni r11, r11, (MSR_VMS|MSR_UMS)
155 /* Define how to call high-level functions. With MMU, virtual mode must be
156 * enabled when calling the high-level function. Clobbers R11.
157 * VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL
160 /* turn on virtual protected mode save */
167 /* turn off virtual protected mode save and user mode save*/
170 rted r0, TOPHYS(1f); \
175 swi r2, r1, PTO+PT_R2; /* Save SDA */ \
176 swi r3, r1, PTO+PT_R3; \
177 swi r4, r1, PTO+PT_R4; \
178 swi r5, r1, PTO+PT_R5; \
179 swi r6, r1, PTO+PT_R6; \
180 swi r7, r1, PTO+PT_R7; \
181 swi r8, r1, PTO+PT_R8; \
182 swi r9, r1, PTO+PT_R9; \
183 swi r10, r1, PTO+PT_R10; \
184 swi r11, r1, PTO+PT_R11; /* save clobbered regs after rval */\
185 swi r12, r1, PTO+PT_R12; \
186 swi r13, r1, PTO+PT_R13; /* Save SDA2 */ \
187 swi r14, r1, PTO+PT_PC; /* PC, before IRQ/trap */ \
188 swi r15, r1, PTO+PT_R15; /* Save LP */ \
189 swi r18, r1, PTO+PT_R18; /* Save asm scratch reg */ \
190 swi r19, r1, PTO+PT_R19; \
191 swi r20, r1, PTO+PT_R20; \
192 swi r21, r1, PTO+PT_R21; \
193 swi r22, r1, PTO+PT_R22; \
194 swi r23, r1, PTO+PT_R23; \
195 swi r24, r1, PTO+PT_R24; \
196 swi r25, r1, PTO+PT_R25; \
197 swi r26, r1, PTO+PT_R26; \
198 swi r27, r1, PTO+PT_R27; \
199 swi r28, r1, PTO+PT_R28; \
200 swi r29, r1, PTO+PT_R29; \
201 swi r30, r1, PTO+PT_R30; \
202 swi r31, r1, PTO+PT_R31; /* Save current task reg */ \
203 mfs r11, rmsr; /* save MSR */ \
204 swi r11, r1, PTO+PT_MSR;
206 #define RESTORE_REGS \
207 lwi r11, r1, PTO+PT_MSR; \
209 lwi r2, r1, PTO+PT_R2; /* restore SDA */ \
210 lwi r3, r1, PTO+PT_R3; \
211 lwi r4, r1, PTO+PT_R4; \
212 lwi r5, r1, PTO+PT_R5; \
213 lwi r6, r1, PTO+PT_R6; \
214 lwi r7, r1, PTO+PT_R7; \
215 lwi r8, r1, PTO+PT_R8; \
216 lwi r9, r1, PTO+PT_R9; \
217 lwi r10, r1, PTO+PT_R10; \
218 lwi r11, r1, PTO+PT_R11; /* restore clobbered regs after rval */\
219 lwi r12, r1, PTO+PT_R12; \
220 lwi r13, r1, PTO+PT_R13; /* restore SDA2 */ \
221 lwi r14, r1, PTO+PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
222 lwi r15, r1, PTO+PT_R15; /* restore LP */ \
223 lwi r18, r1, PTO+PT_R18; /* restore asm scratch reg */ \
224 lwi r19, r1, PTO+PT_R19; \
225 lwi r20, r1, PTO+PT_R20; \
226 lwi r21, r1, PTO+PT_R21; \
227 lwi r22, r1, PTO+PT_R22; \
228 lwi r23, r1, PTO+PT_R23; \
229 lwi r24, r1, PTO+PT_R24; \
230 lwi r25, r1, PTO+PT_R25; \
231 lwi r26, r1, PTO+PT_R26; \
232 lwi r27, r1, PTO+PT_R27; \
233 lwi r28, r1, PTO+PT_R28; \
234 lwi r29, r1, PTO+PT_R29; \
235 lwi r30, r1, PTO+PT_R30; \
236 lwi r31, r1, PTO+PT_R31; /* Restore cur task reg */
239 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \
240 /* See if already in kernel mode.*/ \
242 andi r1, r1, MSR_UMS; \
244 /* Kernel-mode state save. */ \
245 /* Reload kernel stack-ptr. */ \
246 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
247 /* FIXME: I can add these two lines to one */ \
248 /* tophys(r1,r1); */ \
249 /* addik r1, r1, -STATE_SAVE_SIZE; */ \
250 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE; \
253 swi r1, r1, PTO+PT_MODE; \
254 1: /* User-mode state save. */ \
255 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
257 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
258 /* MS these three instructions can be added to one */ \
259 /* addik r1, r1, THREAD_SIZE; */ \
260 /* tophys(r1,r1); */ \
261 /* addik r1, r1, -STATE_SAVE_SIZE; */ \
262 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE; \
264 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
265 swi r11, r1, PTO+PT_R1; /* Store user SP. */ \
266 swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */ \
267 /* MS: I am clearing UMS even in case when I come from kernel space */ \
269 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
276 * System calls are handled here.
279 * Syscall number in r12, args in r5-r10
282 * Trap entered via brki instruction, so BIP bit is set, and interrupts
283 * are masked. This is nice, means we don't have to CLI before state save
285 C_ENTRY(_user_exception):
286 addi r14, r14, 4 /* return address is 4 byte after call */
287 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
289 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
291 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
292 /* MS these three instructions can be added to one */
293 /* addik r1, r1, THREAD_SIZE; */
295 /* addik r1, r1, -STATE_SAVE_SIZE; */
296 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
299 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
300 swi r11, r1, PTO+PT_R1; /* Store user SP. */
302 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
303 /* Save away the syscall number. */
304 swi r12, r1, PTO+PT_R0;
307 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
308 /* Jump to the appropriate function for the system call number in r12
309 * (r12 is not preserved), or return an error if r12 is not valid. The LP
310 * register should point to the location where
311 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */
313 /* Step into virtual mode */
317 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
318 lwi r11, r11, TI_FLAGS /* get flags in thread info */
319 andi r11, r11, _TIF_WORK_SYSCALL_MASK
322 addik r3, r0, -ENOSYS
323 swi r3, r1, PTO + PT_R3
324 brlid r15, do_syscall_trace_enter
325 addik r5, r1, PTO + PT_R0
327 # do_syscall_trace_enter returns the new syscall nr.
329 lwi r5, r1, PTO+PT_R5;
330 lwi r6, r1, PTO+PT_R6;
331 lwi r7, r1, PTO+PT_R7;
332 lwi r8, r1, PTO+PT_R8;
333 lwi r9, r1, PTO+PT_R9;
334 lwi r10, r1, PTO+PT_R10;
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.
338 * The LP register should point to the location where the called function
339 * should return. [note that MAKE_SYS_CALL uses label 1] */
340 /* See if the system call number is valid */
341 addi r11, r12, -__NR_syscalls;
343 /* Figure out which function to use for this system call. */
344 /* Note Microblaze barrel shift is optional, so don't rely on it */
345 add r12, r12, r12; /* convert num -> ptr */
349 /* Trac syscalls and stored them to r0_ram */
350 lwi r3, r12, 0x400 + r0_ram
352 swi r3, r12, 0x400 + r0_ram
355 # Find and jump into the syscall handler.
356 lwi r12, r12, sys_call_table
357 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
358 addi r15, r0, ret_from_trap-8
361 /* The syscall number is invalid, return an error. */
363 rtsd r15, 8; /* looks like a normal subroutine return */
364 addi r3, r0, -ENOSYS;
366 /* Entry point used to return from a syscall/trap */
367 /* We re-enable BIP bit before state restore */
368 C_ENTRY(ret_from_trap):
369 swi r3, r1, PTO + PT_R3
370 swi r4, r1, PTO + PT_R4
372 /* We're returning to user mode, so check for various conditions that
373 * trigger rescheduling. */
374 /* FIXME: Restructure all these flag checks. */
375 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
376 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
377 andi r11, r11, _TIF_WORK_SYSCALL_MASK
380 brlid r15, do_syscall_trace_leave
381 addik r5, r1, PTO + PT_R0
383 /* We're returning to user mode, so check for various conditions that
384 * trigger rescheduling. */
385 /* get thread info from current task */
386 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
387 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
388 andi r11, r11, _TIF_NEED_RESCHED;
391 bralid r15, schedule; /* Call scheduler */
392 nop; /* delay slot */
394 /* Maybe handle a signal */
395 5: /* get thread info from current task*/
396 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
397 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
398 andi r11, r11, _TIF_SIGPENDING;
399 beqi r11, 1f; /* Signals to handle, handle them */
401 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
402 addi r7, r0, 1; /* Arg 3: int in_syscall */
403 bralid r15, do_signal; /* Handle any signals */
404 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
406 /* Finally, return to user state. */
407 1: set_bip; /* Ints masked for state restore */
408 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
412 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
413 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
414 TRAP_return: /* Make global symbol for debugging */
415 rtbd r14, 0; /* Instructions to return from an IRQ */
419 /* These syscalls need access to the struct pt_regs on the stack, so we
420 implement them in assembly (they're basically all wrappers anyway). */
422 C_ENTRY(sys_fork_wrapper):
423 addi r5, r0, SIGCHLD /* Arg 0: flags */
424 lwi r6, r1, PTO+PT_R1 /* Arg 1: child SP (use parent's) */
425 addik r7, r1, PTO /* Arg 2: parent context */
426 add r8. r0, r0 /* Arg 3: (unused) */
427 add r9, r0, r0; /* Arg 4: (unused) */
428 brid do_fork /* Do real work (tail-call) */
429 add r10, r0, r0; /* Arg 5: (unused) */
431 /* This the initial entry point for a new child thread, with an appropriate
432 stack in place that makes it look the the child is in the middle of an
433 syscall. This function is actually `returned to' from switch_thread
434 (copy_thread makes ret_from_fork the return address in each new thread's
436 C_ENTRY(ret_from_fork):
437 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
438 add r3, r5, r0; /* switch_thread returns the prev task */
439 /* ( in the delay slot ) */
440 brid ret_from_trap; /* Do normal trap return */
441 add r3, r0, r0; /* Child's fork call should return 0. */
444 brid microblaze_vfork /* Do real work (tail-call) */
448 bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
449 lwi r6, r1, PTO + PT_R1; /* If so, use paret's stack ptr */
450 1: addik r7, r1, PTO; /* Arg 2: parent context */
451 add r8, r0, r0; /* Arg 3: (unused) */
452 add r9, r0, r0; /* Arg 4: (unused) */
453 brid do_fork /* Do real work (tail-call) */
454 add r10, r0, r0; /* Arg 5: (unused) */
457 brid microblaze_execve; /* Do real work (tail-call).*/
458 addik r8, r1, PTO; /* add user context as 4th arg */
460 C_ENTRY(sys_rt_sigreturn_wrapper):
461 brid sys_rt_sigreturn /* Do real work */
462 addik r5, r1, PTO; /* add user context as 1st arg */
465 * HW EXCEPTION rutine start
467 C_ENTRY(full_exception_trap):
468 /* adjust exception address for privileged instruction
469 * for finding where is it */
471 SAVE_STATE /* Save registers */
472 /* PC, before IRQ/trap - this is one instruction above */
473 swi r17, r1, PTO+PT_PC;
475 /* FIXME this can be store directly in PT_ESR reg.
476 * I tested it but there is a fault */
477 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
478 addik r15, r0, ret_from_exc - 8
480 mfs r7, rfsr; /* save FSR */
481 mts rfsr, r0; /* Clear sticky fsr */
482 rted r0, full_exception
483 addik r5, r1, PTO /* parameter struct pt_regs * regs */
486 * Unaligned data trap.
488 * Unaligned data trap last on 4k page is handled here.
490 * Trap entered via exception, so EE bit is set, and interrupts
491 * are masked. This is nice, means we don't have to CLI before state save
493 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
495 C_ENTRY(unaligned_data_trap):
496 /* MS: I have to save r11 value and then restore it because
497 * set_bit, clear_eip, set_ee use r11 as temp register if MSR
498 * instructions are not used. We don't need to do if MSR instructions
499 * are used and they use r0 instead of r11.
500 * I am using ENTRY_SP which should be primary used only for stack
502 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
503 set_bip; /* equalize initial state for all possible entries */
506 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
507 SAVE_STATE /* Save registers.*/
508 /* PC, before IRQ/trap - this is one instruction above */
509 swi r17, r1, PTO+PT_PC;
511 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
512 addik r15, r0, ret_from_exc-8
513 mfs r3, resr /* ESR */
514 mfs r4, rear /* EAR */
515 rtbd r0, _unaligned_data_exception
516 addik r7, r1, PTO /* parameter struct pt_regs * regs */
521 * If the real exception handler (from hw_exception_handler.S) didn't find
522 * the mapping for the process, then we're thrown here to handle such situation.
524 * Trap entered via exceptions, so EE bit is set, and interrupts
525 * are masked. This is nice, means we don't have to CLI before state save
527 * Build a standard exception frame for TLB Access errors. All TLB exceptions
528 * will bail out to this point if they can't resolve the lightweight TLB fault.
530 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
531 * void do_page_fault(struct pt_regs *regs,
532 * unsigned long address,
533 * unsigned long error_code)
535 /* data and intruction trap - which is choose is resolved int fault.c */
536 C_ENTRY(page_fault_data_trap):
537 SAVE_STATE /* Save registers.*/
538 /* PC, before IRQ/trap - this is one instruction above */
539 swi r17, r1, PTO+PT_PC;
541 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
542 addik r15, r0, ret_from_exc-8
543 mfs r6, rear /* parameter unsigned long address */
544 mfs r7, resr /* parameter unsigned long error_code */
545 rted r0, do_page_fault
546 addik r5, r1, PTO /* parameter struct pt_regs * regs */
548 C_ENTRY(page_fault_instr_trap):
549 SAVE_STATE /* Save registers.*/
550 /* PC, before IRQ/trap - this is one instruction above */
551 swi r17, r1, PTO+PT_PC;
553 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
554 addik r15, r0, ret_from_exc-8
555 mfs r6, rear /* parameter unsigned long address */
556 ori r7, r0, 0 /* parameter unsigned long error_code */
557 rted r0, do_page_fault
558 addik r5, r1, PTO /* parameter struct pt_regs * regs */
560 /* Entry point used to return from an exception. */
561 C_ENTRY(ret_from_exc):
562 lwi r11, r1, PTO + PT_MODE;
563 bnei r11, 2f; /* See if returning to kernel mode, */
564 /* ... if so, skip resched &c. */
566 /* We're returning to user mode, so check for various conditions that
567 trigger rescheduling. */
568 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
569 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
570 andi r11, r11, _TIF_NEED_RESCHED;
573 /* Call the scheduler before returning from a syscall/trap. */
574 bralid r15, schedule; /* Call scheduler */
575 nop; /* delay slot */
577 /* Maybe handle a signal */
578 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
579 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
580 andi r11, r11, _TIF_SIGPENDING;
581 beqi r11, 1f; /* Signals to handle, handle them */
584 * Handle a signal return; Pending signals should be in r18.
586 * Not all registers are saved by the normal trap/interrupt entry
587 * points (for instance, call-saved registers (because the normal
588 * C-compiler calling sequence in the kernel makes sure they're
589 * preserved), and call-clobbered registers in the case of
590 * traps), but signal handlers may want to examine or change the
591 * complete register state. Here we save anything not saved by
592 * the normal entry sequence, so that it may be safely restored
593 * (in a possibly modified form) after do_signal returns. */
594 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
595 addi r7, r0, 0; /* Arg 3: int in_syscall */
596 bralid r15, do_signal; /* Handle any signals */
597 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
599 /* Finally, return to user state. */
600 1: set_bip; /* Ints masked for state restore */
601 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
606 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
608 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
610 /* Return to kernel state. */
611 2: set_bip; /* Ints masked for state restore */
615 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
619 EXC_return: /* Make global symbol for debugging */
620 rtbd r14, 0; /* Instructions to return from an IRQ */
624 * HW EXCEPTION rutine end
628 * Hardware maskable interrupts.
630 * The stack-pointer (r1) should have already been saved to the memory
631 * location PER_CPU(ENTRY_SP).
634 /* MS: we are in physical address */
635 /* Save registers, switch to proper stack, convert SP to virtual.*/
636 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
637 /* MS: See if already in kernel mode. */
643 /* Kernel-mode state save. */
644 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
645 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
647 /* MS: Make room on the stack -> activation record */
648 addik r1, r1, -STATE_SAVE_SIZE;
651 swi r1, r1, PTO + PT_MODE; /* 0 - user mode, 1 - kernel mode */
653 /* User-mode state save. */
654 /* MS: get the saved current */
655 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
657 lwi r1, r1, TS_THREAD_INFO;
658 addik r1, r1, THREAD_SIZE;
661 addik r1, r1, -STATE_SAVE_SIZE;
664 swi r0, r1, PTO + PT_MODE;
665 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
666 swi r11, r1, PTO+PT_R1;
669 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
671 addik r15, r0, irq_call;
672 irq_call:rtbd r0, do_IRQ;
675 /* MS: we are in virtual mode */
677 lwi r11, r1, PTO + PT_MODE;
680 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
681 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
682 andi r11, r11, _TIF_NEED_RESCHED;
684 bralid r15, schedule;
685 nop; /* delay slot */
687 /* Maybe handle a signal */
688 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
689 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
690 andi r11, r11, _TIF_SIGPENDING;
691 beqid r11, no_intr_resched
692 /* Handle a signal return; Pending signals should be in r18. */
693 addi r7, r0, 0; /* Arg 3: int in_syscall */
694 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
695 bralid r15, do_signal; /* Handle any signals */
696 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
698 /* Finally, return to user state. */
700 /* Disable interrupts, we are now committed to the state restore */
702 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
706 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
707 lwi r1, r1, PT_R1 - PT_SIZE;
709 /* MS: Return to kernel state. */
711 #ifdef CONFIG_PREEMPT
712 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
713 /* MS: get preempt_count from thread info */
714 lwi r5, r11, TI_PREEMPT_COUNT;
717 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
718 andi r5, r5, _TIF_NEED_RESCHED;
719 beqi r5, restore /* if zero jump over */
722 /* interrupts are off that's why I am calling preempt_chedule_irq */
723 bralid r15, preempt_schedule_irq
725 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
726 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
727 andi r5, r5, _TIF_NEED_RESCHED;
728 bnei r5, preempt /* if non zero jump to resched */
731 VM_OFF /* MS: turn off MMU */
734 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
737 IRQ_return: /* MS: Make global symbol for debugging */
742 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
743 * and call handling function with saved pt_regs
745 C_ENTRY(_debug_exception):
746 /* BIP bit is set on entry, no interrupts can occur */
747 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
753 /* MS: Kernel-mode state save - kgdb */
754 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
756 /* BIP bit is set on entry, no interrupts can occur */
757 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
759 /* save all regs to pt_reg structure */
760 swi r0, r1, PTO+PT_R0; /* R0 must be saved too */
761 swi r14, r1, PTO+PT_R14 /* rewrite saved R14 value */
762 swi r16, r1, PTO+PT_R16
763 swi r16, r1, PTO+PT_PC; /* PC and r16 are the same */
764 swi r17, r1, PTO+PT_R17
765 /* save special purpose registers to pt_regs */
767 swi r11, r1, PTO+PT_EAR;
769 swi r11, r1, PTO+PT_ESR;
771 swi r11, r1, PTO+PT_FSR;
773 /* stack pointer is in physical address at it is decrease
774 * by STATE_SAVE_SIZE but we need to get correct R1 value */
775 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + STATE_SAVE_SIZE;
776 swi r11, r1, PTO+PT_R1
777 /* MS: r31 - current pointer isn't changed */
780 addi r5, r1, PTO /* pass pt_reg address as the first arg */
781 la r15, r0, dbtrap_call; /* return address */
782 rtbd r0, microblaze_kgdb_break
785 /* MS: Place handler for brki from kernel space if KGDB is OFF.
786 * It is very unlikely that another brki instruction is called. */
789 /* MS: User-mode state save - gdb */
790 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
792 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
793 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
796 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
798 swi r17, r1, PTO+PT_R17;
799 swi r16, r1, PTO+PT_R16;
800 swi r16, r1, PTO+PT_PC; /* Save LP */
801 swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */
802 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
803 swi r11, r1, PTO+PT_R1; /* Store user SP. */
804 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
808 addik r15, r0, dbtrap_call;
809 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
810 rtbd r0, sw_exception
813 /* MS: The first instruction for the second part of the gdb/kgdb */
814 set_bip; /* Ints masked for state restore */
815 lwi r11, r1, PTO + PT_MODE;
817 /* MS: Return to user space - gdb */
818 /* Get current task ptr into r11 */
819 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
820 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
821 andi r11, r11, _TIF_NEED_RESCHED;
824 /* Call the scheduler before returning from a syscall/trap. */
825 bralid r15, schedule; /* Call scheduler */
826 nop; /* delay slot */
828 /* Maybe handle a signal */
829 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
830 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
831 andi r11, r11, _TIF_SIGPENDING;
832 beqi r11, 1f; /* Signals to handle, handle them */
834 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
835 addi r7, r0, 0; /* Arg 3: int in_syscall */
836 bralid r15, do_signal; /* Handle any signals */
837 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
839 /* Finally, return to user state. */
840 1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
843 /* MS: Restore all regs */
845 lwi r17, r1, PTO+PT_R17;
846 lwi r16, r1, PTO+PT_R16;
847 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space */
848 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
849 DBTRAP_return_user: /* MS: Make global symbol for debugging */
850 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
853 /* MS: Return to kernel state - kgdb */
856 /* MS: Restore all regs */
858 lwi r14, r1, PTO+PT_R14;
859 lwi r16, r1, PTO+PT_PC;
860 lwi r17, r1, PTO+PT_R17;
861 addik r1, r1, STATE_SAVE_SIZE; /* MS: Clean up stack space */
863 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
864 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
869 /* prepare return value */
870 addk r3, r0, CURRENT_TASK
872 /* save registers in cpu_context */
873 /* use r11 and r12, volatile registers, as temp register */
874 /* give start of cpu_context for previous process */
875 addik r11, r5, TI_CPU_CONTEXT
878 /* skip volatile registers.
879 * they are saved on stack when we jumped to _switch_to() */
880 /* dedicated registers */
887 /* save non-volatile registers */
900 /* special purpose registers */
910 /* update r31, the current-give me pointer to task which will be next */
911 lwi CURRENT_TASK, r6, TI_TASK
912 /* stored it to current_save too */
913 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
915 /* get new process' cpu context and restore */
916 /* give me start where start context of next task */
917 addik r11, r6, TI_CPU_CONTEXT
919 /* non-volatile registers */
932 /* dedicated registers */
939 /* skip volatile registers */
943 /* special purpose registers */
953 brai 0x70; /* Jump back to FS-boot */
955 /* These are compiled and loaded into high memory, then
956 * copied into place in mach_early_setup */
957 .section .init.ivt, "ax"
959 /* this is very important - here is the reset vector */
960 /* in current MMU branch you don't care what is here - it is
961 * used from bootloader site - but this is correct for FS-BOOT */
964 brai TOPHYS(_user_exception); /* syscall handler */
965 brai TOPHYS(_interrupt); /* Interrupt handler */
966 brai TOPHYS(_debug_exception); /* debug trap handler */
967 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
970 #include "syscall_table.S"
972 syscall_table_size=(.-sys_call_table)
979 .ascii "IRQ (PREEMPTED)\0"
980 type_SYSCALL_PREEMPT:
981 .ascii " SYSCALL (PREEMPTED)\0"
984 * Trap decoding for stack unwinder
985 * Tuples are (start addr, end addr, string)
986 * If return address lies on [start addr, end addr],
987 * unwinder displays 'string'
991 .global microblaze_trap_handlers
992 microblaze_trap_handlers:
993 /* Exact matches come first */
994 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
995 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
996 /* Fuzzy matches go here */
997 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
998 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1000 .word 0 ; .word 0 ; .word 0