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 r16, r1, PTO+PT_R16; \
190 swi r17, r1, PTO+PT_R17; \
191 swi r18, r1, PTO+PT_R18; /* Save asm scratch reg */ \
192 swi r19, r1, PTO+PT_R19; \
193 swi r20, r1, PTO+PT_R20; \
194 swi r21, r1, PTO+PT_R21; \
195 swi r22, r1, PTO+PT_R22; \
196 swi r23, r1, PTO+PT_R23; \
197 swi r24, r1, PTO+PT_R24; \
198 swi r25, r1, PTO+PT_R25; \
199 swi r26, r1, PTO+PT_R26; \
200 swi r27, r1, PTO+PT_R27; \
201 swi r28, r1, PTO+PT_R28; \
202 swi r29, r1, PTO+PT_R29; \
203 swi r30, r1, PTO+PT_R30; \
204 swi r31, r1, PTO+PT_R31; /* Save current task reg */ \
205 mfs r11, rmsr; /* save MSR */ \
206 swi r11, r1, PTO+PT_MSR;
208 #define RESTORE_REGS \
209 lwi r11, r1, PTO+PT_MSR; \
211 lwi r2, r1, PTO+PT_R2; /* restore SDA */ \
212 lwi r3, r1, PTO+PT_R3; \
213 lwi r4, r1, PTO+PT_R4; \
214 lwi r5, r1, PTO+PT_R5; \
215 lwi r6, r1, PTO+PT_R6; \
216 lwi r7, r1, PTO+PT_R7; \
217 lwi r8, r1, PTO+PT_R8; \
218 lwi r9, r1, PTO+PT_R9; \
219 lwi r10, r1, PTO+PT_R10; \
220 lwi r11, r1, PTO+PT_R11; /* restore clobbered regs after rval */\
221 lwi r12, r1, PTO+PT_R12; \
222 lwi r13, r1, PTO+PT_R13; /* restore SDA2 */ \
223 lwi r14, r1, PTO+PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
224 lwi r15, r1, PTO+PT_R15; /* restore LP */ \
225 lwi r16, r1, PTO+PT_R16; \
226 lwi r17, r1, PTO+PT_R17; \
227 lwi r18, r1, PTO+PT_R18; /* restore asm scratch reg */ \
228 lwi r19, r1, PTO+PT_R19; \
229 lwi r20, r1, PTO+PT_R20; \
230 lwi r21, r1, PTO+PT_R21; \
231 lwi r22, r1, PTO+PT_R22; \
232 lwi r23, r1, PTO+PT_R23; \
233 lwi r24, r1, PTO+PT_R24; \
234 lwi r25, r1, PTO+PT_R25; \
235 lwi r26, r1, PTO+PT_R26; \
236 lwi r27, r1, PTO+PT_R27; \
237 lwi r28, r1, PTO+PT_R28; \
238 lwi r29, r1, PTO+PT_R29; \
239 lwi r30, r1, PTO+PT_R30; \
240 lwi r31, r1, PTO+PT_R31; /* Restore cur task reg */
243 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \
244 /* See if already in kernel mode.*/ \
246 andi r1, r1, MSR_UMS; \
248 /* Kernel-mode state save. */ \
249 /* Reload kernel stack-ptr. */ \
250 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
251 /* FIXME: I can add these two lines to one */ \
252 /* tophys(r1,r1); */ \
253 /* addik r1, r1, -STATE_SAVE_SIZE; */ \
254 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE; \
257 swi r1, r1, PTO+PT_MODE; \
258 1: /* User-mode state save. */ \
259 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
261 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
262 /* MS these three instructions can be added to one */ \
263 /* addik r1, r1, THREAD_SIZE; */ \
264 /* tophys(r1,r1); */ \
265 /* addik r1, r1, -STATE_SAVE_SIZE; */ \
266 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE; \
268 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
269 swi r11, r1, PTO+PT_R1; /* Store user SP. */ \
270 swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */ \
271 /* MS: I am clearing UMS even in case when I come from kernel space */ \
273 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
280 * System calls are handled here.
283 * Syscall number in r12, args in r5-r10
286 * Trap entered via brki instruction, so BIP bit is set, and interrupts
287 * are masked. This is nice, means we don't have to CLI before state save
289 C_ENTRY(_user_exception):
290 addi r14, r14, 4 /* return address is 4 byte after call */
291 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
293 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
295 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
296 /* MS these three instructions can be added to one */
297 /* addik r1, r1, THREAD_SIZE; */
299 /* addik r1, r1, -STATE_SAVE_SIZE; */
300 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
302 swi r0, r1, PTO + PT_R3
303 swi r0, r1, PTO + PT_R4
305 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
306 swi r11, r1, PTO+PT_R1; /* Store user SP. */
308 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
309 /* Save away the syscall number. */
310 swi r12, r1, PTO+PT_R0;
313 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
314 /* Jump to the appropriate function for the system call number in r12
315 * (r12 is not preserved), or return an error if r12 is not valid. The LP
316 * register should point to the location where
317 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */
319 /* Step into virtual mode */
323 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
324 lwi r11, r11, TI_FLAGS /* get flags in thread info */
325 andi r11, r11, _TIF_WORK_SYSCALL_MASK
328 addik r3, r0, -ENOSYS
329 swi r3, r1, PTO + PT_R3
330 brlid r15, do_syscall_trace_enter
331 addik r5, r1, PTO + PT_R0
333 # do_syscall_trace_enter returns the new syscall nr.
335 lwi r5, r1, PTO+PT_R5;
336 lwi r6, r1, PTO+PT_R6;
337 lwi r7, r1, PTO+PT_R7;
338 lwi r8, r1, PTO+PT_R8;
339 lwi r9, r1, PTO+PT_R9;
340 lwi r10, r1, PTO+PT_R10;
342 /* Jump to the appropriate function for the system call number in r12
343 * (r12 is not preserved), or return an error if r12 is not valid.
344 * The LP register should point to the location where the called function
345 * should return. [note that MAKE_SYS_CALL uses label 1] */
346 /* See if the system call number is valid */
347 addi r11, r12, -__NR_syscalls;
349 /* Figure out which function to use for this system call. */
350 /* Note Microblaze barrel shift is optional, so don't rely on it */
351 add r12, r12, r12; /* convert num -> ptr */
355 /* Trac syscalls and stored them to r0_ram */
356 lwi r3, r12, 0x400 + r0_ram
358 swi r3, r12, 0x400 + r0_ram
361 # Find and jump into the syscall handler.
362 lwi r12, r12, sys_call_table
363 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
364 addi r15, r0, ret_from_trap-8
367 /* The syscall number is invalid, return an error. */
369 rtsd r15, 8; /* looks like a normal subroutine return */
370 addi r3, r0, -ENOSYS;
372 /* Entry point used to return from a syscall/trap */
373 /* We re-enable BIP bit before state restore */
374 C_ENTRY(ret_from_trap):
375 swi r3, r1, PTO + PT_R3
376 swi r4, r1, PTO + PT_R4
378 /* We're returning to user mode, so check for various conditions that
379 * trigger rescheduling. */
380 /* FIXME: Restructure all these flag checks. */
381 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
382 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
383 andi r11, r11, _TIF_WORK_SYSCALL_MASK
386 brlid r15, do_syscall_trace_leave
387 addik r5, r1, PTO + PT_R0
389 /* We're returning to user mode, so check for various conditions that
390 * trigger rescheduling. */
391 /* get thread info from current task */
392 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
393 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
394 andi r11, r11, _TIF_NEED_RESCHED;
397 bralid r15, schedule; /* Call scheduler */
398 nop; /* delay slot */
400 /* Maybe handle a signal */
401 5: /* get thread info from current task*/
402 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
403 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
404 andi r11, r11, _TIF_SIGPENDING;
405 beqi r11, 1f; /* Signals to handle, handle them */
407 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
408 addi r7, r0, 1; /* Arg 3: int in_syscall */
409 bralid r15, do_signal; /* Handle any signals */
410 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
412 /* Finally, return to user state. */
413 1: set_bip; /* Ints masked for state restore */
414 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
418 addik r1, r1, STATE_SAVE_SIZE /* Clean up stack space. */
419 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
420 TRAP_return: /* Make global symbol for debugging */
421 rtbd r14, 0; /* Instructions to return from an IRQ */
425 /* These syscalls need access to the struct pt_regs on the stack, so we
426 implement them in assembly (they're basically all wrappers anyway). */
428 C_ENTRY(sys_fork_wrapper):
429 addi r5, r0, SIGCHLD /* Arg 0: flags */
430 lwi r6, r1, PTO+PT_R1 /* Arg 1: child SP (use parent's) */
431 addik r7, r1, PTO /* Arg 2: parent context */
432 add r8. r0, r0 /* Arg 3: (unused) */
433 add r9, r0, r0; /* Arg 4: (unused) */
434 brid do_fork /* Do real work (tail-call) */
435 add r10, r0, r0; /* Arg 5: (unused) */
437 /* This the initial entry point for a new child thread, with an appropriate
438 stack in place that makes it look the the child is in the middle of an
439 syscall. This function is actually `returned to' from switch_thread
440 (copy_thread makes ret_from_fork the return address in each new thread's
442 C_ENTRY(ret_from_fork):
443 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
444 add r3, r5, r0; /* switch_thread returns the prev task */
445 /* ( in the delay slot ) */
446 brid ret_from_trap; /* Do normal trap return */
447 add r3, r0, r0; /* Child's fork call should return 0. */
450 brid microblaze_vfork /* Do real work (tail-call) */
454 bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
455 lwi r6, r1, PTO + PT_R1; /* If so, use paret's stack ptr */
456 1: addik r7, r1, PTO; /* Arg 2: parent context */
457 add r8, r0, r0; /* Arg 3: (unused) */
458 add r9, r0, r0; /* Arg 4: (unused) */
459 brid do_fork /* Do real work (tail-call) */
460 add r10, r0, r0; /* Arg 5: (unused) */
463 brid microblaze_execve; /* Do real work (tail-call).*/
464 addik r8, r1, PTO; /* add user context as 4th arg */
466 C_ENTRY(sys_rt_sigreturn_wrapper):
467 brid sys_rt_sigreturn /* Do real work */
468 addik r5, r1, PTO; /* add user context as 1st arg */
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_PC; /* PC and r16 are the same */
769 /* save special purpose registers to pt_regs */
771 swi r11, r1, PTO+PT_EAR;
773 swi r11, r1, PTO+PT_ESR;
775 swi r11, r1, PTO+PT_FSR;
777 /* stack pointer is in physical address at it is decrease
778 * by STATE_SAVE_SIZE but we need to get correct R1 value */
779 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + STATE_SAVE_SIZE;
780 swi r11, r1, PTO+PT_R1
781 /* MS: r31 - current pointer isn't changed */
784 addi r5, r1, PTO /* pass pt_reg address as the first arg */
785 la r15, r0, dbtrap_call; /* return address */
786 rtbd r0, microblaze_kgdb_break
789 /* MS: Place handler for brki from kernel space if KGDB is OFF.
790 * It is very unlikely that another brki instruction is called. */
793 /* MS: User-mode state save - gdb */
794 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
796 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
797 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
800 addik r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack. */
802 swi r16, r1, PTO+PT_PC; /* Save LP */
803 swi r0, r1, PTO + PT_MODE; /* Was in user-mode. */
804 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
805 swi r11, r1, PTO+PT_R1; /* Store user SP. */
806 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
810 addik r15, r0, dbtrap_call;
811 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
812 rtbd r0, sw_exception
815 /* MS: The first instruction for the second part of the gdb/kgdb */
816 set_bip; /* Ints masked for state restore */
817 lwi r11, r1, PTO + PT_MODE;
819 /* MS: Return to user space - gdb */
820 /* Get current task ptr into r11 */
821 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
822 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
823 andi r11, r11, _TIF_NEED_RESCHED;
826 /* Call the scheduler before returning from a syscall/trap. */
827 bralid r15, schedule; /* Call scheduler */
828 nop; /* delay slot */
830 /* Maybe handle a signal */
831 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
832 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
833 andi r11, r11, _TIF_SIGPENDING;
834 beqi r11, 1f; /* Signals to handle, handle them */
836 addik r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
837 addi r7, r0, 0; /* Arg 3: int in_syscall */
838 bralid r15, do_signal; /* Handle any signals */
839 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
841 /* Finally, return to user state. */
842 1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
845 /* MS: Restore all regs */
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 addik r1, r1, STATE_SAVE_SIZE; /* MS: Clean up stack space */
862 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
863 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
868 /* prepare return value */
869 addk r3, r0, CURRENT_TASK
871 /* save registers in cpu_context */
872 /* use r11 and r12, volatile registers, as temp register */
873 /* give start of cpu_context for previous process */
874 addik r11, r5, TI_CPU_CONTEXT
877 /* skip volatile registers.
878 * they are saved on stack when we jumped to _switch_to() */
879 /* dedicated registers */
886 /* save non-volatile registers */
899 /* special purpose registers */
909 /* update r31, the current-give me pointer to task which will be next */
910 lwi CURRENT_TASK, r6, TI_TASK
911 /* stored it to current_save too */
912 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
914 /* get new process' cpu context and restore */
915 /* give me start where start context of next task */
916 addik r11, r6, TI_CPU_CONTEXT
918 /* non-volatile registers */
931 /* dedicated registers */
938 /* skip volatile registers */
942 /* special purpose registers */
952 brai 0x70; /* Jump back to FS-boot */
954 /* These are compiled and loaded into high memory, then
955 * copied into place in mach_early_setup */
956 .section .init.ivt, "ax"
958 /* this is very important - here is the reset vector */
959 /* in current MMU branch you don't care what is here - it is
960 * used from bootloader site - but this is correct for FS-BOOT */
963 brai TOPHYS(_user_exception); /* syscall handler */
964 brai TOPHYS(_interrupt); /* Interrupt handler */
965 brai TOPHYS(_debug_exception); /* debug trap handler */
966 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
969 #include "syscall_table.S"
971 syscall_table_size=(.-sys_call_table)
978 .ascii "IRQ (PREEMPTED)\0"
979 type_SYSCALL_PREEMPT:
980 .ascii " SYSCALL (PREEMPTED)\0"
983 * Trap decoding for stack unwinder
984 * Tuples are (start addr, end addr, string)
985 * If return address lies on [start addr, end addr],
986 * unwinder displays 'string'
990 .global microblaze_trap_handlers
991 microblaze_trap_handlers:
992 /* Exact matches come first */
993 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
994 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
995 /* Fuzzy matches go here */
996 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
997 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
999 .word 0 ; .word 0 ; .word 0