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>
37 /* Create space for syscalls counting. */
39 .global syscall_debug_table
42 .space (__NR_syscalls * 4)
45 #define C_ENTRY(name) .globl name; .align 4; name
48 * Various ways of setting and clearing BIP in flags reg.
49 * This is mucky, but necessary using microblaze version that
50 * allows msr ops to write to BIP
52 #if CONFIG_XILINX_MICROBLAZE0_USE_MSR_INSTR
92 msrclr r0, MSR_VMS | MSR_UMS
97 andi r11, r11, ~MSR_BIP
103 ori r11, r11, MSR_BIP
109 andi r11, r11, ~MSR_EIP
121 andi r11, r11, ~MSR_IE
133 ori r11, r11, MSR_VMS
134 andni r11, r11, MSR_UMS
140 ori r11, r11, MSR_VMS
141 andni r11, r11, MSR_UMS
147 andni r11, r11, MSR_UMS
153 andni r11, r11, (MSR_VMS|MSR_UMS)
158 /* Define how to call high-level functions. With MMU, virtual mode must be
159 * enabled when calling the high-level function. Clobbers R11.
160 * VM_ON, VM_OFF, DO_JUMP_BIPCLR, DO_CALL
163 /* turn on virtual protected mode save */
170 /* turn off virtual protected mode save and user mode save*/
173 rted r0, TOPHYS(1f); \
178 swi r2, r1, PT_R2; /* Save SDA */ \
186 swi r10, r1, PT_R10; \
187 swi r11, r1, PT_R11; /* save clobbered regs after rval */\
188 swi r12, r1, PT_R12; \
189 swi r13, r1, PT_R13; /* Save SDA2 */ \
190 swi r14, r1, PT_PC; /* PC, before IRQ/trap */ \
191 swi r15, r1, PT_R15; /* Save LP */ \
192 swi r16, r1, PT_R16; \
193 swi r17, r1, PT_R17; \
194 swi r18, r1, PT_R18; /* Save asm scratch reg */ \
195 swi r19, r1, PT_R19; \
196 swi r20, r1, PT_R20; \
197 swi r21, r1, PT_R21; \
198 swi r22, r1, PT_R22; \
199 swi r23, r1, PT_R23; \
200 swi r24, r1, PT_R24; \
201 swi r25, r1, PT_R25; \
202 swi r26, r1, PT_R26; \
203 swi r27, r1, PT_R27; \
204 swi r28, r1, PT_R28; \
205 swi r29, r1, PT_R29; \
206 swi r30, r1, PT_R30; \
207 swi r31, r1, PT_R31; /* Save current task reg */ \
208 mfs r11, rmsr; /* save MSR */ \
211 #define RESTORE_REGS \
212 lwi r11, r1, PT_MSR; \
214 lwi r2, r1, PT_R2; /* restore SDA */ \
222 lwi r10, r1, PT_R10; \
223 lwi r11, r1, PT_R11; /* restore clobbered regs after rval */\
224 lwi r12, r1, PT_R12; \
225 lwi r13, r1, PT_R13; /* restore SDA2 */ \
226 lwi r14, r1, PT_PC; /* RESTORE_LINK PC, before IRQ/trap */\
227 lwi r15, r1, PT_R15; /* restore LP */ \
228 lwi r16, r1, PT_R16; \
229 lwi r17, r1, PT_R17; \
230 lwi r18, r1, PT_R18; /* restore asm scratch reg */ \
231 lwi r19, r1, PT_R19; \
232 lwi r20, r1, PT_R20; \
233 lwi r21, r1, PT_R21; \
234 lwi r22, r1, PT_R22; \
235 lwi r23, r1, PT_R23; \
236 lwi r24, r1, PT_R24; \
237 lwi r25, r1, PT_R25; \
238 lwi r26, r1, PT_R26; \
239 lwi r27, r1, PT_R27; \
240 lwi r28, r1, PT_R28; \
241 lwi r29, r1, PT_R29; \
242 lwi r30, r1, PT_R30; \
243 lwi r31, r1, PT_R31; /* Restore cur task reg */
246 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* save stack */ \
247 /* See if already in kernel mode.*/ \
249 andi r1, r1, MSR_UMS; \
251 /* Kernel-mode state save. */ \
252 /* Reload kernel stack-ptr. */ \
253 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
254 /* FIXME: I can add these two lines to one */ \
255 /* tophys(r1,r1); */ \
256 /* addik r1, r1, -PT_SIZE; */ \
257 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
260 swi r1, r1, PT_MODE; \
261 1: /* User-mode state save. */ \
262 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
264 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */ \
265 /* MS these three instructions can be added to one */ \
266 /* addik r1, r1, THREAD_SIZE; */ \
267 /* tophys(r1,r1); */ \
268 /* addik r1, r1, -PT_SIZE; */ \
269 addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
271 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); \
272 swi r11, r1, PT_R1; /* Store user SP. */ \
273 swi r0, r1, PT_MODE; /* Was in user-mode. */ \
274 /* MS: I am clearing UMS even in case when I come from kernel space */ \
276 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
283 * System calls are handled here.
286 * Syscall number in r12, args in r5-r10
289 * Trap entered via brki instruction, so BIP bit is set, and interrupts
290 * are masked. This is nice, means we don't have to CLI before state save
292 C_ENTRY(_user_exception):
293 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
294 addi r14, r14, 4 /* return address is 4 byte after call */
301 /* Kernel-mode state save - kernel execve */
302 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
305 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
308 swi r1, r1, PT_MODE; /* pt_regs -> kernel mode */
310 nop; /* Fill delay slot */
312 /* User-mode state save. */
314 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
316 lwi r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
317 /* calculate kernel stack pointer from task struct 8k */
318 addik r1, r1, THREAD_SIZE;
321 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
326 swi r0, r1, PT_MODE; /* Was in user-mode. */
327 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
328 swi r11, r1, PT_R1; /* Store user SP. */
330 2: lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
331 /* Save away the syscall number. */
335 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
336 /* Jump to the appropriate function for the system call number in r12
337 * (r12 is not preserved), or return an error if r12 is not valid. The LP
338 * register should point to the location where
339 * the called function should return. [note that MAKE_SYS_CALL uses label 1] */
341 /* Step into virtual mode */
345 lwi r11, CURRENT_TASK, TS_THREAD_INFO /* get thread info */
346 lwi r11, r11, TI_FLAGS /* get flags in thread info */
347 andi r11, r11, _TIF_WORK_SYSCALL_MASK
350 addik r3, r0, -ENOSYS
352 brlid r15, do_syscall_trace_enter
355 # do_syscall_trace_enter returns the new syscall nr.
364 /* Jump to the appropriate function for the system call number in r12
365 * (r12 is not preserved), or return an error if r12 is not valid.
366 * The LP register should point to the location where the called function
367 * should return. [note that MAKE_SYS_CALL uses label 1] */
368 /* See if the system call number is valid */
369 addi r11, r12, -__NR_syscalls;
371 /* Figure out which function to use for this system call. */
372 /* Note Microblaze barrel shift is optional, so don't rely on it */
373 add r12, r12, r12; /* convert num -> ptr */
377 /* Trac syscalls and stored them to syscall_debug_table */
378 /* The first syscall location stores total syscall number */
379 lwi r3, r0, syscall_debug_table
381 swi r3, r0, syscall_debug_table
382 lwi r3, r12, syscall_debug_table
384 swi r3, r12, syscall_debug_table
387 # Find and jump into the syscall handler.
388 lwi r12, r12, sys_call_table
389 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
390 addi r15, r0, ret_from_trap-8
393 /* The syscall number is invalid, return an error. */
395 rtsd r15, 8; /* looks like a normal subroutine return */
396 addi r3, r0, -ENOSYS;
398 /* Entry point used to return from a syscall/trap */
399 /* We re-enable BIP bit before state restore */
400 C_ENTRY(ret_from_trap):
404 lwi r11, r1, PT_MODE;
405 /* See if returning to kernel mode, if so, skip resched &c. */
407 /* We're returning to user mode, so check for various conditions that
408 * trigger rescheduling. */
409 /* FIXME: Restructure all these flag checks. */
410 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
411 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
412 andi r11, r11, _TIF_WORK_SYSCALL_MASK
415 brlid r15, do_syscall_trace_leave
418 /* We're returning to user mode, so check for various conditions that
419 * trigger rescheduling. */
420 /* get thread info from current task */
421 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
422 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
423 andi r11, r11, _TIF_NEED_RESCHED;
426 bralid r15, schedule; /* Call scheduler */
427 nop; /* delay slot */
429 /* Maybe handle a signal */
430 5: /* get thread info from current task*/
431 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
432 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
433 andi r11, r11, _TIF_SIGPENDING;
434 beqi r11, 1f; /* Signals to handle, handle them */
436 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
437 addi r7, r0, 1; /* Arg 3: int in_syscall */
438 bralid r15, do_signal; /* Handle any signals */
439 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
441 /* Finally, return to user state. */
442 1: set_bip; /* Ints masked for state restore */
443 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
447 addik r1, r1, PT_SIZE /* Clean up stack space. */
448 lwi r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
451 /* Return to kernel state. */
452 2: set_bip; /* Ints masked for state restore */
456 addik r1, r1, PT_SIZE /* Clean up stack space. */
459 TRAP_return: /* Make global symbol for debugging */
460 rtbd r14, 0; /* Instructions to return from an IRQ */
464 /* These syscalls need access to the struct pt_regs on the stack, so we
465 implement them in assembly (they're basically all wrappers anyway). */
467 C_ENTRY(sys_fork_wrapper):
468 addi r5, r0, SIGCHLD /* Arg 0: flags */
469 lwi r6, r1, PT_R1 /* Arg 1: child SP (use parent's) */
470 addik r7, r1, 0 /* Arg 2: parent context */
471 add r8, r0, r0 /* Arg 3: (unused) */
472 add r9, r0, r0; /* Arg 4: (unused) */
473 brid do_fork /* Do real work (tail-call) */
474 add r10, r0, r0; /* Arg 5: (unused) */
476 /* This the initial entry point for a new child thread, with an appropriate
477 stack in place that makes it look the the child is in the middle of an
478 syscall. This function is actually `returned to' from switch_thread
479 (copy_thread makes ret_from_fork the return address in each new thread's
481 C_ENTRY(ret_from_fork):
482 bralid r15, schedule_tail; /* ...which is schedule_tail's arg */
483 add r3, r5, r0; /* switch_thread returns the prev task */
484 /* ( in the delay slot ) */
485 brid ret_from_trap; /* Do normal trap return */
486 add r3, r0, r0; /* Child's fork call should return 0. */
489 brid microblaze_vfork /* Do real work (tail-call) */
493 bnei r6, 1f; /* See if child SP arg (arg 1) is 0. */
494 lwi r6, r1, PT_R1; /* If so, use paret's stack ptr */
495 1: addik r7, r1, 0; /* Arg 2: parent context */
496 lwi r9, r1, PT_R8; /* parent tid. */
497 lwi r10, r1, PT_R9; /* child tid. */
498 /* do_fork will pick up TLS from regs->r10. */
499 brid do_fork /* Do real work (tail-call) */
500 add r8, r0, r0; /* Arg 3: (unused) */
503 brid microblaze_execve; /* Do real work (tail-call).*/
504 addik r8, r1, 0; /* add user context as 4th arg */
506 C_ENTRY(sys_rt_sigreturn_wrapper):
507 brid sys_rt_sigreturn /* Do real work */
508 addik r5, r1, 0; /* add user context as 1st arg */
511 * HW EXCEPTION rutine start
513 C_ENTRY(full_exception_trap):
514 /* adjust exception address for privileged instruction
515 * for finding where is it */
517 SAVE_STATE /* Save registers */
518 /* PC, before IRQ/trap - this is one instruction above */
521 /* FIXME this can be store directly in PT_ESR reg.
522 * I tested it but there is a fault */
523 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
524 addik r15, r0, ret_from_exc - 8
526 mfs r7, rfsr; /* save FSR */
527 mts rfsr, r0; /* Clear sticky fsr */
528 rted r0, full_exception
529 addik r5, r1, 0 /* parameter struct pt_regs * regs */
532 * Unaligned data trap.
534 * Unaligned data trap last on 4k page is handled here.
536 * Trap entered via exception, so EE bit is set, and interrupts
537 * are masked. This is nice, means we don't have to CLI before state save
539 * The assembler routine is in "arch/microblaze/kernel/hw_exception_handler.S"
541 C_ENTRY(unaligned_data_trap):
542 /* MS: I have to save r11 value and then restore it because
543 * set_bit, clear_eip, set_ee use r11 as temp register if MSR
544 * instructions are not used. We don't need to do if MSR instructions
545 * are used and they use r0 instead of r11.
546 * I am using ENTRY_SP which should be primary used only for stack
548 swi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
549 set_bip; /* equalize initial state for all possible entries */
552 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
553 SAVE_STATE /* Save registers.*/
554 /* PC, before IRQ/trap - this is one instruction above */
557 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
558 addik r15, r0, ret_from_exc-8
559 mfs r3, resr /* ESR */
560 mfs r4, rear /* EAR */
561 rtbd r0, _unaligned_data_exception
562 addik r7, r1, 0 /* parameter struct pt_regs * regs */
567 * If the real exception handler (from hw_exception_handler.S) didn't find
568 * the mapping for the process, then we're thrown here to handle such situation.
570 * Trap entered via exceptions, so EE bit is set, and interrupts
571 * are masked. This is nice, means we don't have to CLI before state save
573 * Build a standard exception frame for TLB Access errors. All TLB exceptions
574 * will bail out to this point if they can't resolve the lightweight TLB fault.
576 * The C function called is in "arch/microblaze/mm/fault.c", declared as:
577 * void do_page_fault(struct pt_regs *regs,
578 * unsigned long address,
579 * unsigned long error_code)
581 /* data and intruction trap - which is choose is resolved int fault.c */
582 C_ENTRY(page_fault_data_trap):
583 SAVE_STATE /* Save registers.*/
584 /* PC, before IRQ/trap - this is one instruction above */
587 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
588 addik r15, r0, ret_from_exc-8
589 mfs r6, rear /* parameter unsigned long address */
590 mfs r7, resr /* parameter unsigned long error_code */
591 rted r0, do_page_fault
592 addik r5, r1, 0 /* parameter struct pt_regs * regs */
594 C_ENTRY(page_fault_instr_trap):
595 SAVE_STATE /* Save registers.*/
596 /* PC, before IRQ/trap - this is one instruction above */
599 /* where the trap should return need -8 to adjust for rtsd r15, 8 */
600 addik r15, r0, ret_from_exc-8
601 mfs r6, rear /* parameter unsigned long address */
602 ori r7, r0, 0 /* parameter unsigned long error_code */
603 rted r0, do_page_fault
604 addik r5, r1, 0 /* parameter struct pt_regs * regs */
606 /* Entry point used to return from an exception. */
607 C_ENTRY(ret_from_exc):
608 lwi r11, r1, PT_MODE;
609 bnei r11, 2f; /* See if returning to kernel mode, */
610 /* ... if so, skip resched &c. */
612 /* We're returning to user mode, so check for various conditions that
613 trigger rescheduling. */
614 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
615 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
616 andi r11, r11, _TIF_NEED_RESCHED;
619 /* Call the scheduler before returning from a syscall/trap. */
620 bralid r15, schedule; /* Call scheduler */
621 nop; /* delay slot */
623 /* Maybe handle a signal */
624 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
625 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
626 andi r11, r11, _TIF_SIGPENDING;
627 beqi r11, 1f; /* Signals to handle, handle them */
630 * Handle a signal return; Pending signals should be in r18.
632 * Not all registers are saved by the normal trap/interrupt entry
633 * points (for instance, call-saved registers (because the normal
634 * C-compiler calling sequence in the kernel makes sure they're
635 * preserved), and call-clobbered registers in the case of
636 * traps), but signal handlers may want to examine or change the
637 * complete register state. Here we save anything not saved by
638 * the normal entry sequence, so that it may be safely restored
639 * (in a possibly modified form) after do_signal returns. */
640 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
641 addi r7, r0, 0; /* Arg 3: int in_syscall */
642 bralid r15, do_signal; /* Handle any signals */
643 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
645 /* Finally, return to user state. */
646 1: set_bip; /* Ints masked for state restore */
647 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
652 addik r1, r1, PT_SIZE /* Clean up stack space. */
654 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
656 /* Return to kernel state. */
657 2: set_bip; /* Ints masked for state restore */
661 addik r1, r1, PT_SIZE /* Clean up stack space. */
665 EXC_return: /* Make global symbol for debugging */
666 rtbd r14, 0; /* Instructions to return from an IRQ */
670 * HW EXCEPTION rutine end
674 * Hardware maskable interrupts.
676 * The stack-pointer (r1) should have already been saved to the memory
677 * location PER_CPU(ENTRY_SP).
680 /* MS: we are in physical address */
681 /* Save registers, switch to proper stack, convert SP to virtual.*/
682 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
683 /* MS: See if already in kernel mode. */
689 /* Kernel-mode state save. */
690 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
691 tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
693 /* MS: Make room on the stack -> activation record */
694 addik r1, r1, -PT_SIZE;
697 swi r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */
699 /* User-mode state save. */
700 /* MS: get the saved current */
701 lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
703 lwi r1, r1, TS_THREAD_INFO;
704 addik r1, r1, THREAD_SIZE;
707 addik r1, r1, -PT_SIZE;
711 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
715 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
717 addik r15, r0, irq_call;
718 irq_call:rtbd r0, do_IRQ;
721 /* MS: we are in virtual mode */
723 lwi r11, r1, PT_MODE;
726 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
727 lwi r11, r11, TI_FLAGS; /* MS: get flags from thread info */
728 andi r11, r11, _TIF_NEED_RESCHED;
730 bralid r15, schedule;
731 nop; /* delay slot */
733 /* Maybe handle a signal */
734 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* MS: get thread info */
735 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
736 andi r11, r11, _TIF_SIGPENDING;
737 beqid r11, no_intr_resched
738 /* Handle a signal return; Pending signals should be in r18. */
739 addi r7, r0, 0; /* Arg 3: int in_syscall */
740 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
741 bralid r15, do_signal; /* Handle any signals */
742 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
744 /* Finally, return to user state. */
746 /* Disable interrupts, we are now committed to the state restore */
748 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);
752 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
753 lwi r1, r1, PT_R1 - PT_SIZE;
755 /* MS: Return to kernel state. */
757 #ifdef CONFIG_PREEMPT
758 lwi r11, CURRENT_TASK, TS_THREAD_INFO;
759 /* MS: get preempt_count from thread info */
760 lwi r5, r11, TI_PREEMPT_COUNT;
763 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
764 andi r5, r5, _TIF_NEED_RESCHED;
765 beqi r5, restore /* if zero jump over */
768 /* interrupts are off that's why I am calling preempt_chedule_irq */
769 bralid r15, preempt_schedule_irq
771 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
772 lwi r5, r11, TI_FLAGS; /* get flags in thread info */
773 andi r5, r5, _TIF_NEED_RESCHED;
774 bnei r5, preempt /* if non zero jump to resched */
777 VM_OFF /* MS: turn off MMU */
780 addik r1, r1, PT_SIZE /* MS: Clean up stack space. */
783 IRQ_return: /* MS: Make global symbol for debugging */
788 * Debug trap for KGDB. Enter to _debug_exception by brki r16, 0x18
789 * and call handling function with saved pt_regs
791 C_ENTRY(_debug_exception):
792 /* BIP bit is set on entry, no interrupts can occur */
793 swi r1, r0, TOPHYS(PER_CPU(ENTRY_SP))
799 /* MS: Kernel-mode state save - kgdb */
800 lwi r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
802 /* BIP bit is set on entry, no interrupts can occur */
803 addik r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE;
805 /* save all regs to pt_reg structure */
806 swi r0, r1, PT_R0; /* R0 must be saved too */
807 swi r14, r1, PT_R14 /* rewrite saved R14 value */
808 swi r16, r1, PT_PC; /* PC and r16 are the same */
809 /* save special purpose registers to pt_regs */
817 /* stack pointer is in physical address at it is decrease
818 * by PT_SIZE but we need to get correct R1 value */
819 addik r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE;
821 /* MS: r31 - current pointer isn't changed */
824 addi r5, r1, 0 /* pass pt_reg address as the first arg */
825 addik r15, r0, dbtrap_call; /* return address */
826 rtbd r0, microblaze_kgdb_break
829 /* MS: Place handler for brki from kernel space if KGDB is OFF.
830 * It is very unlikely that another brki instruction is called. */
833 /* MS: User-mode state save - gdb */
834 1: lwi r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
836 lwi r1, r1, TS_THREAD_INFO; /* get the thread info */
837 addik r1, r1, THREAD_SIZE; /* calculate kernel stack pointer */
840 addik r1, r1, -PT_SIZE; /* Make room on the stack. */
842 swi r16, r1, PT_PC; /* Save LP */
843 swi r0, r1, PT_MODE; /* Was in user-mode. */
844 lwi r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
845 swi r11, r1, PT_R1; /* Store user SP. */
846 lwi CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
850 addik r15, r0, dbtrap_call;
851 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
852 rtbd r0, sw_exception
855 /* MS: The first instruction for the second part of the gdb/kgdb */
856 set_bip; /* Ints masked for state restore */
857 lwi r11, r1, PT_MODE;
859 /* MS: Return to user space - gdb */
860 /* Get current task ptr into r11 */
861 lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
862 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
863 andi r11, r11, _TIF_NEED_RESCHED;
866 /* Call the scheduler before returning from a syscall/trap. */
867 bralid r15, schedule; /* Call scheduler */
868 nop; /* delay slot */
870 /* Maybe handle a signal */
871 5: lwi r11, CURRENT_TASK, TS_THREAD_INFO; /* get thread info */
872 lwi r11, r11, TI_FLAGS; /* get flags in thread info */
873 andi r11, r11, _TIF_SIGPENDING;
874 beqi r11, 1f; /* Signals to handle, handle them */
876 addik r5, r1, 0; /* Arg 1: struct pt_regs *regs */
877 addi r7, r0, 0; /* Arg 3: int in_syscall */
878 bralid r15, do_signal; /* Handle any signals */
879 add r6, r0, r0; /* Arg 2: sigset_t *oldset */
881 /* Finally, return to user state. */
882 1: swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */
885 /* MS: Restore all regs */
887 addik r1, r1, PT_SIZE /* Clean up stack space */
888 lwi r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
889 DBTRAP_return_user: /* MS: Make global symbol for debugging */
890 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
893 /* MS: Return to kernel state - kgdb */
896 /* MS: Restore all regs */
900 addik r1, r1, PT_SIZE; /* MS: Clean up stack space */
902 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
903 rtbd r16, 0; /* MS: Instructions to return from a debug trap */
908 /* prepare return value */
909 addk r3, r0, CURRENT_TASK
911 /* save registers in cpu_context */
912 /* use r11 and r12, volatile registers, as temp register */
913 /* give start of cpu_context for previous process */
914 addik r11, r5, TI_CPU_CONTEXT
917 /* skip volatile registers.
918 * they are saved on stack when we jumped to _switch_to() */
919 /* dedicated registers */
926 /* save non-volatile registers */
939 /* special purpose registers */
949 /* update r31, the current-give me pointer to task which will be next */
950 lwi CURRENT_TASK, r6, TI_TASK
951 /* stored it to current_save too */
952 swi CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE)
954 /* get new process' cpu context and restore */
955 /* give me start where start context of next task */
956 addik r11, r6, TI_CPU_CONTEXT
958 /* non-volatile registers */
971 /* dedicated registers */
978 /* skip volatile registers */
982 /* special purpose registers */
992 brai 0; /* Jump to reset vector */
994 /* These are compiled and loaded into high memory, then
995 * copied into place in mach_early_setup */
996 .section .init.ivt, "ax"
997 #if CONFIG_MANUAL_RESET_VECTOR
999 brai CONFIG_MANUAL_RESET_VECTOR
1002 brai TOPHYS(_user_exception); /* syscall handler */
1004 brai TOPHYS(_interrupt); /* Interrupt handler */
1006 brai TOPHYS(_debug_exception); /* debug trap handler */
1008 brai TOPHYS(_hw_exception_handler); /* HW exception handler */
1010 .section .rodata,"a"
1011 #include "syscall_table.S"
1013 syscall_table_size=(.-sys_call_table)
1020 .ascii "IRQ (PREEMPTED)\0"
1021 type_SYSCALL_PREEMPT:
1022 .ascii " SYSCALL (PREEMPTED)\0"
1025 * Trap decoding for stack unwinder
1026 * Tuples are (start addr, end addr, string)
1027 * If return address lies on [start addr, end addr],
1028 * unwinder displays 'string'
1032 .global microblaze_trap_handlers
1033 microblaze_trap_handlers:
1034 /* Exact matches come first */
1035 .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
1036 .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
1037 /* Fuzzy matches go here */
1038 .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
1039 .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
1041 .word 0 ; .word 0 ; .word 0