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 swi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
462 swi r4, r1, PTO+PT_R4;
463 brlid r15, sys_rt_sigreturn /* Do real work */
464 addik r5, r1, PTO; /* add user context as 1st arg */
465 lwi r3, r1, PTO+PT_R3; /* restore saved r3, r4 registers */
466 lwi r4, r1, PTO+PT_R4;
467 bri ret_from_trap /* fall through will not work here due to align */
471 * HW EXCEPTION rutine start
473 C_ENTRY(full_exception_trap):
474 /* adjust exception address for privileged instruction
475 * for finding where is it */
477 SAVE_STATE /* Save registers */
478 /* PC, before IRQ/trap - this is one instruction above */
479 swi r17, r1, PTO+PT_PC;
481 /* FIXME this can be store directly in PT_ESR reg.
482 * I tested it but there is a fault */
483 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
484 addik r15, r0, ret_from_exc - 8
486 mfs r7, rfsr; /* save FSR */
487 mts rfsr, r0; /* Clear sticky fsr */
488 rted r0, full_exception
489 addik r5, r1, PTO /* parameter struct pt_regs * regs */
492 * Unaligned data trap.
494 * Unaligned data trap last on 4k page is handled here.
496 * Trap entered via exception, so EE bit is set, and interrupts
497 * are masked. This is nice, means we don't have to CLI before state save
499 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
501 C_ENTRY(unaligned_data_trap):
502 /* MS: I have to save r11 value and then restore it because
503 * set_bit, clear_eip, set_ee use r11 as temp register if MSR
504 * instructions are not used. We don't need to do if MSR instructions
505 * are used and they use r0 instead of r11.
506 * I am using ENTRY_SP which should be primary used only for stack
508 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
509 set_bip; /* equalize initial state for all possible entries */
512 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
513 SAVE_STATE /* Save registers.*/
514 /* PC, before IRQ/trap - this is one instruction above */
515 swi r17, r1, PTO+PT_PC;
517 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
518 addik r15, r0, ret_from_exc-8
519 mfs r3, resr /* ESR */
520 mfs r4, rear /* EAR */
521 rtbd r0, _unaligned_data_exception
522 addik r7, r1, PTO /* parameter struct pt_regs * regs */
527 * If the real exception handler (from hw_exception_handler.S) didn't find
528 * the mapping for the process, then we're thrown here to handle such situation.
530 * Trap entered via exceptions, so EE bit is set, and interrupts
531 * are masked. This is nice, means we don't have to CLI before state save
533 * Build a standard exception frame for TLB Access errors. All TLB exceptions
534 * will bail out to this point if they can't resolve the lightweight TLB fault.
536 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
537 * void do_page_fault(struct pt_regs *regs,
538 * unsigned long address,
539 * unsigned long error_code)
541 /* data and intruction trap - which is choose is resolved int fault.c */
542 C_ENTRY(page_fault_data_trap):
543 SAVE_STATE /* Save registers.*/
544 /* PC, before IRQ/trap - this is one instruction above */
545 swi r17, r1, PTO+PT_PC;
547 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
548 addik r15, r0, ret_from_exc-8
549 mfs r6, rear /* parameter unsigned long address */
550 mfs r7, resr /* parameter unsigned long error_code */
551 rted r0, do_page_fault
552 addik r5, r1, PTO /* parameter struct pt_regs * regs */
554 C_ENTRY(page_fault_instr_trap):
555 SAVE_STATE /* Save registers.*/
556 /* PC, before IRQ/trap - this is one instruction above */
557 swi r17, r1, PTO+PT_PC;
559 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
560 addik r15, r0, ret_from_exc-8
561 mfs r6, rear /* parameter unsigned long address */
562 ori r7, r0, 0 /* parameter unsigned long error_code */
563 rted r0, do_page_fault
564 addik r5, r1, PTO /* parameter struct pt_regs * regs */
566 /* Entry point used to return from an exception. */
567 C_ENTRY(ret_from_exc):
568 lwi r11, r1, PTO + PT_MODE;
569 bnei r11, 2f; /* See if returning to kernel mode, */
570 /* ... if so, skip resched &c. */
572 /* We're returning to user mode, so check for various conditions that
573 trigger rescheduling. */
574 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
575 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
576 andi r11, r11, _TIF_NEED_RESCHED;
579 /* Call the scheduler before returning from a syscall/trap. */
580 bralid r15, schedule; /* Call scheduler */
581 nop; /* delay slot */
583 /* Maybe handle a signal */
584 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
585 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
586 andi r11, r11, _TIF_SIGPENDING;
587 beqi r11, 1f; /* Signals to handle, handle them */
590 * Handle a signal return; Pending signals should be in r18.
592 * Not all registers are saved by the normal trap/interrupt entry
593 * points (for instance, call-saved registers (because the normal
594 * C-compiler calling sequence in the kernel makes sure they're
595 * preserved), and call-clobbered registers in the case of
596 * traps), but signal handlers may want to examine or change the
597 * complete register state. Here we save anything not saved by
598 * the normal entry sequence, so that it may be safely restored
599 * (in a possibly modified form) after do_signal returns. */
600 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
601 addi r7, r0, 0; /* Arg 3: int in_syscall */
602 bralid r15, do_signal; /* Handle any signals */
603 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
605 /* Finally, return to user state. */
606 1: set_bip; /* Ints masked for state restore */
607 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
612 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
614 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
616 /* Return to kernel state. */
617 2: set_bip; /* Ints masked for state restore */
621 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
625 EXC_return: /* Make global symbol for debugging */
626 rtbd r14, 0; /* Instructions to return from an IRQ */
630 * HW EXCEPTION rutine end
634 * Hardware maskable interrupts.
636 * The stack-pointer (r1) should have already been saved to the memory
637 * location PER_CPU(ENTRY_SP).
640 /* MS: we are in physical address */
641 /* Save registers, switch to proper stack, convert SP to virtual.*/
642 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
643 /* MS: See if already in kernel mode. */
649 /* Kernel-mode state save. */
650 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
651 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
653 /* MS: Make room on the stack -> activation record */
654 addik r1, r1, -STATE_SAVE_SIZE;
657 swi r1, r1, PTO + PT_MODE; /* 0 - user mode, 1 - kernel mode */
659 /* User-mode state save. */
660 /* MS: get the saved current */
661 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
663 lwi r1, r1, TS_THREAD_INFO;
664 addik r1, r1, THREAD_SIZE;
667 addik r1, r1, -STATE_SAVE_SIZE;
670 swi r0, r1, PTO + PT_MODE;
671 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
672 swi r11, r1, PTO+PT_R1;
675 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
677 addik r15, r0, irq_call;
678 irq_call:rtbd r0, do_IRQ;
681 /* MS: we are in virtual mode */
683 lwi r11, r1, PTO + PT_MODE;
686 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
687 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
688 andi r11, r11, _TIF_NEED_RESCHED;
690 bralid r15, schedule;
691 nop; /* delay slot */
693 /* Maybe handle a signal */
694 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
695 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
696 andi r11, r11, _TIF_SIGPENDING;
697 beqid r11, no_intr_resched
698 /* Handle a signal return; Pending signals should be in r18. */
699 addi r7, r0, 0; /* Arg 3: int in_syscall */
700 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
701 bralid r15, do_signal; /* Handle any signals */
702 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
704 /* Finally, return to user state. */
706 /* Disable interrupts, we are now committed to the state restore */
708 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
712 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
713 lwi r1, r1, PT_R1 - PT_SIZE;
715 /* MS: Return to kernel state. */
717 #ifdef CONFIG_PREEMPT
718 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
719 /* MS: get preempt_count from thread info */
720 lwi r5, r11, TI_PREEMPT_COUNT;
723 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
724 andi r5, r5, _TIF_NEED_RESCHED;
725 beqi r5, restore /* if zero jump over */
728 /* interrupts are off that's why I am calling preempt_chedule_irq */
729 bralid r15, preempt_schedule_irq
731 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
732 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
733 andi r5, r5, _TIF_NEED_RESCHED;
734 bnei r5, preempt /* if non zero jump to resched */
737 VM_OFF /* MS: turn off MMU */
740 addik r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
743 IRQ_return: /* MS: Make global symbol for debugging */
748 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
749 * and call handling function with saved pt_regs
751 C_ENTRY(_debug_exception):
752 /* BIP bit is set on entry, no interrupts can occur */
753 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
759 /* MS: Kernel-mode state save - kgdb */
760 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
762 /* BIP bit is set on entry, no interrupts can occur */
763 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
765 /* save all regs to pt_reg structure */
766 swi r0, r1, PTO+PT_R0; /* R0 must be saved too */
767 swi r14, r1, PTO+PT_R14 /* rewrite saved R14 value */
768 swi r16, r1, PTO+PT_R16
769 swi r16, r1, PTO+PT_PC; /* PC and r16 are the same */
770 swi r17, r1, PTO+PT_R17
771 /* save special purpose registers to pt_regs */
773 swi r11, r1, PTO+PT_EAR;
775 swi r11, r1, PTO+PT_ESR;
777 swi r11, r1, PTO+PT_FSR;
779 /* stack pointer is in physical address at it is decrease
780 * by STATE_SAVE_SIZE but we need to get correct R1 value */
781 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + STATE_SAVE_SIZE;
782 swi r11, r1, PTO+PT_R1
783 /* MS: r31 - current pointer isn't changed */
786 addi r5, r1, PTO /* pass pt_reg address as the first arg */
787 la r15, r0, dbtrap_call; /* return address */
788 rtbd r0, microblaze_kgdb_break
791 /* MS: Place handler for brki from kernel space if KGDB is OFF.
792 * It is very unlikely that another brki instruction is called. */
795 /* MS: User-mode state save - gdb */
796 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
798 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
799 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
802 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
804 swi r17, r1, PTO+PT_R17;
805 swi r16, r1, PTO+PT_R16;
806 swi r16, r1, PTO+PT_PC; /* Save LP */
807 swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */
808 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
809 swi r11, r1, PTO+PT_R1; /* Store user SP. */
810 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
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
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, PTO + PT_MODE;
823 /* MS: Return to user space - gdb */
824 /* Get current task ptr into r11 */
825 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
826 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
827 andi r11, r11, _TIF_NEED_RESCHED;
830 /* Call the scheduler before returning from a syscall/trap. */
831 bralid r15, schedule; /* Call scheduler */
832 nop; /* delay slot */
834 /* Maybe handle a signal */
835 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
836 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
837 andi r11, r11, _TIF_SIGPENDING;
838 beqi r11, 1f; /* Signals to handle, handle them */
840 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
841 addi r7, r0, 0; /* Arg 3: int in_syscall */
842 bralid r15, do_signal; /* Handle any signals */
843 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
845 /* Finally, return to user state. */
846 1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
849 /* MS: Restore all regs */
851 lwi r17, r1, PTO+PT_R17;
852 lwi r16, r1, PTO+PT_R16;
853 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space */
854 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
855 DBTRAP_return_user: /* MS: Make global symbol for debugging */
856 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
859 /* MS: Return to kernel state - kgdb */
862 /* MS: Restore all regs */
864 lwi r14, r1, PTO+PT_R14;
865 lwi r16, r1, PTO+PT_PC;
866 lwi r17, r1, PTO+PT_R17;
867 addik r1, r1, STATE_SAVE_SIZE; /* MS: Clean up stack space */
869 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
870 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
875 /* prepare return value */
876 addk r3, r0, CURRENT_TASK
878 /* save registers in cpu_context */
879 /* use r11 and r12, volatile registers, as temp register */
880 /* give start of cpu_context for previous process */
881 addik r11, r5, TI_CPU_CONTEXT
884 /* skip volatile registers.
885 * they are saved on stack when we jumped to _switch_to() */
886 /* dedicated registers */
893 /* save non-volatile registers */
906 /* special purpose registers */
916 /* update r31, the current-give me pointer to task which will be next */
917 lwi CURRENT_TASK, r6, TI_TASK
918 /* stored it to current_save too */
919 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
921 /* get new process' cpu context and restore */
922 /* give me start where start context of next task */
923 addik r11, r6, TI_CPU_CONTEXT
925 /* non-volatile registers */
938 /* dedicated registers */
945 /* skip volatile registers */
949 /* special purpose registers */
959 brai 0x70; /* Jump back to FS-boot */
961 /* These are compiled and loaded into high memory, then
962 * copied into place in mach_early_setup */
963 .section .init.ivt, "ax"
965 /* this is very important - here is the reset vector */
966 /* in current MMU branch you don't care what is here - it is
967 * used from bootloader site - but this is correct for FS-BOOT */
970 brai TOPHYS(_user_exception); /* syscall handler */
971 brai TOPHYS(_interrupt); /* Interrupt handler */
972 brai TOPHYS(_debug_exception); /* debug trap handler */
973 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
976 #include "syscall_table.S"
978 syscall_table_size=(.-sys_call_table)
985 .ascii "IRQ (PREEMPTED)\0"
986 type_SYSCALL_PREEMPT:
987 .ascii " SYSCALL (PREEMPTED)\0"
990 * Trap decoding for stack unwinder
991 * Tuples are (start addr, end addr, string)
992 * If return address lies on [start addr, end addr],
993 * unwinder displays 'string'
997 .global microblaze_trap_handlers
998 microblaze_trap_handlers:
999 /* Exact matches come first */
1000 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
1001 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
1002 /* Fuzzy matches go here */
1003 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
1004 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1006 .word 0 ; .word 0 ; .word 0