2 * arch/v850/kernel/entry.S -- Low-level system-call handling, trap handlers,
3 * and context-switching
5 * Copyright (C) 2001,02,03 NEC Electronics Corporation
6 * Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
8 * This file is subject to the terms and conditions of the GNU General
9 * Public License. See the file COPYING in the main directory of this
10 * archive for more details.
12 * Written by Miles Bader <miles@gnu.org>
15 #include <linux/sys.h>
17 #include <asm/entry.h>
18 #include <asm/current.h>
19 #include <asm/thread_info.h>
20 #include <asm/clinkage.h>
21 #include <asm/processor.h>
23 #include <asm/errno.h>
25 #include <asm/asm-offsets.h>
28 /* Make a slightly more convenient alias for C_SYMBOL_NAME. */
29 #define CSYM C_SYMBOL_NAME
32 /* The offset of the struct pt_regs in a state-save-frame on the stack. */
33 #define PTO STATE_SAVE_PT_OFFSET
36 /* Save argument registers to the state-save-frame pointed to by EP. */
37 #define SAVE_ARG_REGS \
38 sst.w r6, PTO+PT_GPR(6)[ep]; \
39 sst.w r7, PTO+PT_GPR(7)[ep]; \
40 sst.w r8, PTO+PT_GPR(8)[ep]; \
41 sst.w r9, PTO+PT_GPR(9)[ep]
42 /* Restore argument registers from the state-save-frame pointed to by EP. */
43 #define RESTORE_ARG_REGS \
44 sld.w PTO+PT_GPR(6)[ep], r6; \
45 sld.w PTO+PT_GPR(7)[ep], r7; \
46 sld.w PTO+PT_GPR(8)[ep], r8; \
47 sld.w PTO+PT_GPR(9)[ep], r9
49 /* Save value return registers to the state-save-frame pointed to by EP. */
50 #define SAVE_RVAL_REGS \
51 sst.w r10, PTO+PT_GPR(10)[ep]; \
52 sst.w r11, PTO+PT_GPR(11)[ep]
53 /* Restore value return registers from the state-save-frame pointed to by EP. */
54 #define RESTORE_RVAL_REGS \
55 sld.w PTO+PT_GPR(10)[ep], r10; \
56 sld.w PTO+PT_GPR(11)[ep], r11
59 #define SAVE_CALL_CLOBBERED_REGS_BEFORE_ARGS \
60 sst.w r1, PTO+PT_GPR(1)[ep]; \
61 sst.w r5, PTO+PT_GPR(5)[ep]
62 #define SAVE_CALL_CLOBBERED_REGS_AFTER_RVAL \
63 sst.w r12, PTO+PT_GPR(12)[ep]; \
64 sst.w r13, PTO+PT_GPR(13)[ep]; \
65 sst.w r14, PTO+PT_GPR(14)[ep]; \
66 sst.w r15, PTO+PT_GPR(15)[ep]; \
67 sst.w r16, PTO+PT_GPR(16)[ep]; \
68 sst.w r17, PTO+PT_GPR(17)[ep]; \
69 sst.w r18, PTO+PT_GPR(18)[ep]; \
70 sst.w r19, PTO+PT_GPR(19)[ep]
71 #define RESTORE_CALL_CLOBBERED_REGS_BEFORE_ARGS \
72 sld.w PTO+PT_GPR(1)[ep], r1; \
73 sld.w PTO+PT_GPR(5)[ep], r5
74 #define RESTORE_CALL_CLOBBERED_REGS_AFTER_RVAL \
75 sld.w PTO+PT_GPR(12)[ep], r12; \
76 sld.w PTO+PT_GPR(13)[ep], r13; \
77 sld.w PTO+PT_GPR(14)[ep], r14; \
78 sld.w PTO+PT_GPR(15)[ep], r15; \
79 sld.w PTO+PT_GPR(16)[ep], r16; \
80 sld.w PTO+PT_GPR(17)[ep], r17; \
81 sld.w PTO+PT_GPR(18)[ep], r18; \
82 sld.w PTO+PT_GPR(19)[ep], r19
84 /* Save `call clobbered' registers to the state-save-frame pointed to by EP. */
85 #define SAVE_CALL_CLOBBERED_REGS \
86 SAVE_CALL_CLOBBERED_REGS_BEFORE_ARGS; \
89 SAVE_CALL_CLOBBERED_REGS_AFTER_RVAL
90 /* Restore `call clobbered' registers from the state-save-frame pointed to
92 #define RESTORE_CALL_CLOBBERED_REGS \
93 RESTORE_CALL_CLOBBERED_REGS_BEFORE_ARGS; \
96 RESTORE_CALL_CLOBBERED_REGS_AFTER_RVAL
98 /* Save `call clobbered' registers except for the return-value registers
99 to the state-save-frame pointed to by EP. */
100 #define SAVE_CALL_CLOBBERED_REGS_NO_RVAL \
101 SAVE_CALL_CLOBBERED_REGS_BEFORE_ARGS; \
103 SAVE_CALL_CLOBBERED_REGS_AFTER_RVAL
104 /* Restore `call clobbered' registers except for the return-value registers
105 from the state-save-frame pointed to by EP. */
106 #define RESTORE_CALL_CLOBBERED_REGS_NO_RVAL \
107 RESTORE_CALL_CLOBBERED_REGS_BEFORE_ARGS; \
109 RESTORE_CALL_CLOBBERED_REGS_AFTER_RVAL
111 /* Save `call saved' registers to the state-save-frame pointed to by EP. */
112 #define SAVE_CALL_SAVED_REGS \
113 sst.w r2, PTO+PT_GPR(2)[ep]; \
114 sst.w r20, PTO+PT_GPR(20)[ep]; \
115 sst.w r21, PTO+PT_GPR(21)[ep]; \
116 sst.w r22, PTO+PT_GPR(22)[ep]; \
117 sst.w r23, PTO+PT_GPR(23)[ep]; \
118 sst.w r24, PTO+PT_GPR(24)[ep]; \
119 sst.w r25, PTO+PT_GPR(25)[ep]; \
120 sst.w r26, PTO+PT_GPR(26)[ep]; \
121 sst.w r27, PTO+PT_GPR(27)[ep]; \
122 sst.w r28, PTO+PT_GPR(28)[ep]; \
123 sst.w r29, PTO+PT_GPR(29)[ep]
124 /* Restore `call saved' registers from the state-save-frame pointed to by EP. */
125 #define RESTORE_CALL_SAVED_REGS \
126 sld.w PTO+PT_GPR(2)[ep], r2; \
127 sld.w PTO+PT_GPR(20)[ep], r20; \
128 sld.w PTO+PT_GPR(21)[ep], r21; \
129 sld.w PTO+PT_GPR(22)[ep], r22; \
130 sld.w PTO+PT_GPR(23)[ep], r23; \
131 sld.w PTO+PT_GPR(24)[ep], r24; \
132 sld.w PTO+PT_GPR(25)[ep], r25; \
133 sld.w PTO+PT_GPR(26)[ep], r26; \
134 sld.w PTO+PT_GPR(27)[ep], r27; \
135 sld.w PTO+PT_GPR(28)[ep], r28; \
136 sld.w PTO+PT_GPR(29)[ep], r29
139 /* Save the PC stored in the special register SAVEREG to the state-save-frame
140 pointed to by EP. r19 is clobbered. */
141 #define SAVE_PC(savereg) \
142 stsr SR_ ## savereg, r19; \
143 sst.w r19, PTO+PT_PC[ep]
144 /* Restore the PC from the state-save-frame pointed to by EP, to the special
145 register SAVEREG. LP is clobbered (it is used as a scratch register
146 because the POP_STATE macro restores it, and this macro is usually used
147 inside POP_STATE). */
148 #define RESTORE_PC(savereg) \
149 sld.w PTO+PT_PC[ep], lp; \
150 ldsr lp, SR_ ## savereg
151 /* Save the PSW register stored in the special register SAVREG to the
152 state-save-frame pointed to by EP. r19 is clobbered. */
153 #define SAVE_PSW(savereg) \
154 stsr SR_ ## savereg, r19; \
155 sst.w r19, PTO+PT_PSW[ep]
156 /* Restore the PSW register from the state-save-frame pointed to by EP, to
157 the special register SAVEREG. LP is clobbered (it is used as a scratch
158 register because the POP_STATE macro restores it, and this macro is
159 usually used inside POP_STATE). */
160 #define RESTORE_PSW(savereg) \
161 sld.w PTO+PT_PSW[ep], lp; \
162 ldsr lp, SR_ ## savereg
164 /* Save CTPC/CTPSW/CTBP registers to the state-save-frame pointed to by REG.
166 #define SAVE_CT_REGS \
168 sst.w r19, PTO+PT_CTPC[ep]; \
169 stsr SR_CTPSW, r19; \
170 sst.w r19, PTO+PT_CTPSW[ep]; \
172 sst.w r19, PTO+PT_CTBP[ep]
173 /* Restore CTPC/CTPSW/CTBP registers from the state-save-frame pointed to by EP.
174 LP is clobbered (it is used as a scratch register because the POP_STATE
175 macro restores it, and this macro is usually used inside POP_STATE). */
176 #define RESTORE_CT_REGS \
177 sld.w PTO+PT_CTPC[ep], lp; \
179 sld.w PTO+PT_CTPSW[ep], lp; \
181 sld.w PTO+PT_CTBP[ep], lp; \
185 /* Push register state, except for the stack pointer, on the stack in the
186 form of a state-save-frame (plus some extra padding), in preparation for
187 a system call. This macro makes sure that the EP, GP, and LP
188 registers are saved, and TYPE identifies the set of extra registers to
189 be saved as well. Also copies (the new value of) SP to EP. */
190 #define PUSH_STATE(type) \
191 addi -STATE_SAVE_SIZE, sp, sp; /* Make room on the stack. */ \
192 st.w ep, PTO+PT_GPR(GPR_EP)[sp]; \
194 sst.w gp, PTO+PT_GPR(GPR_GP)[ep]; \
195 sst.w lp, PTO+PT_GPR(GPR_LP)[ep]; \
197 /* Pop a register state pushed by PUSH_STATE, except for the stack pointer,
198 from the the stack. */
199 #define POP_STATE(type) \
201 type ## _STATE_RESTORER; \
202 sld.w PTO+PT_GPR(GPR_GP)[ep], gp; \
203 sld.w PTO+PT_GPR(GPR_LP)[ep], lp; \
204 sld.w PTO+PT_GPR(GPR_EP)[ep], ep; \
205 addi STATE_SAVE_SIZE, sp, sp /* Clean up our stack space. */
208 /* Switch to the kernel stack if necessary, and push register state on the
209 stack in the form of a state-save-frame. Also load the current task
210 pointer if switching from user mode. The stack-pointer (r3) should have
211 already been saved to the memory location SP_SAVE_LOC (the reason for
212 this is that the interrupt vectors may be beyond a 22-bit signed offset
213 jump from the actual interrupt handler, and this allows them to save the
214 stack-pointer and use that register to do an indirect jump). This macro
215 makes sure that `special' registers, system registers, and the stack
216 pointer are saved; TYPE identifies the set of extra registers to be
217 saved as well. SYSCALL_NUM is the register in which the system-call
218 number this state is for is stored (r0 if this isn't a system call).
219 Interrupts should already be disabled when calling this. */
220 #define SAVE_STATE(type, syscall_num, sp_save_loc) \
221 tst1 0, KM; /* See if already in kernel mode. */ \
223 ld.w sp_save_loc, sp; /* ... yes, use saved SP. */ \
225 1: ld.w KSP, sp; /* ... no, switch to kernel stack. */ \
226 2: PUSH_STATE(type); \
227 ld.b KM, r19; /* Remember old kernel-mode. */ \
228 sst.w r19, PTO+PT_KERNEL_MODE[ep]; \
229 ld.w sp_save_loc, r19; /* Remember old SP. */ \
230 sst.w r19, PTO+PT_GPR(GPR_SP)[ep]; \
231 mov 1, r19; /* Now definitely in kernel-mode. */ \
233 GET_CURRENT_TASK(CURRENT_TASK); /* Fetch the current task pointer. */ \
234 /* Save away the syscall number. */ \
235 sst.w syscall_num, PTO+PT_CUR_SYSCALL[ep]
238 /* Save register state not normally saved by PUSH_STATE for TYPE, to the
239 state-save-frame on the stack; also copies SP to EP. r19 may be trashed. */
240 #define SAVE_EXTRA_STATE(type) \
242 type ## _EXTRA_STATE_SAVER
243 /* Restore register state not normally restored by POP_STATE for TYPE,
244 from the state-save-frame on the stack; also copies SP to EP.
245 r19 may be trashed. */
246 #define RESTORE_EXTRA_STATE(type) \
248 type ## _EXTRA_STATE_RESTORER
250 /* Save any call-clobbered registers not normally saved by PUSH_STATE for
251 TYPE, to the state-save-frame on the stack.
252 EP may be trashed, but is not guaranteed to contain a copy of SP
253 (unlike after most SAVE_... macros). r19 may be trashed. */
254 #define SAVE_EXTRA_STATE_FOR_SCHEDULE(type) \
255 type ## _SCHEDULE_EXTRA_STATE_SAVER
256 /* Restore any call-clobbered registers not normally restored by
257 POP_STATE for TYPE, to the state-save-frame on the stack.
258 EP may be trashed, but is not guaranteed to contain a copy of SP
259 (unlike after most RESTORE_... macros). r19 may be trashed. */
260 #define RESTORE_EXTRA_STATE_FOR_SCHEDULE(type) \
261 type ## _SCHEDULE_EXTRA_STATE_RESTORER
264 /* These are extra_state_saver/restorer values for a user trap. Note
265 that we save the argument registers so that restarted syscalls will
266 function properly (otherwise it wouldn't be necessary), and we must
267 _not_ restore the return-value registers (so that traps can return a
268 value!), but call-clobbered registers are not saved at all, as the
269 caller of the syscall function should have saved them. */
271 #define TRAP_RET reti
272 /* Traps don't save call-clobbered registers (but do still save arg regs).
273 We preserve PSw to keep long-term state, namely interrupt status (for traps
274 from kernel-mode), and the single-step flag (for user traps). */
275 #define TRAP_STATE_SAVER \
279 /* When traps return, they just leave call-clobbered registers (except for arg
280 regs) with whatever value they have from the kernel. Traps don't preserve
281 the PSW, but we zero EIPSW to ensure it doesn't contain anything dangerous
282 (in particular, the single-step flag). */
283 #define TRAP_STATE_RESTORER \
287 /* Save registers not normally saved by traps. We need to save r12, even
288 though it's nominally call-clobbered, because it's used when restarting
289 a system call (the signal-handling path uses SAVE_EXTRA_STATE, and
290 expects r12 to be restored when the trap returns). */
291 #define TRAP_EXTRA_STATE_SAVER \
293 sst.w r12, PTO+PT_GPR(12)[ep]; \
294 SAVE_CALL_SAVED_REGS; \
296 #define TRAP_EXTRA_STATE_RESTORER \
298 sld.w PTO+PT_GPR(12)[ep], r12; \
299 RESTORE_CALL_SAVED_REGS; \
301 /* Save registers prior to calling scheduler (just before trap returns).
302 We have to save the return-value registers to preserve the trap's return
303 value. Note that ..._SCHEDULE_EXTRA_STATE_SAVER, unlike most ..._SAVER
304 macros, is required to setup EP itself if EP is needed (this is because
305 in many cases, the macro is empty). */
306 #define TRAP_SCHEDULE_EXTRA_STATE_SAVER \
309 /* Note that ..._SCHEDULE_EXTRA_STATE_RESTORER, unlike most ..._RESTORER
310 macros, is required to setup EP itself if EP is needed (this is because
311 in many cases, the macro is empty). */
312 #define TRAP_SCHEDULE_EXTRA_STATE_RESTORER \
316 /* Register saving/restoring for maskable interrupts. */
318 #define IRQ_STATE_SAVER \
319 SAVE_CALL_CLOBBERED_REGS; \
322 #define IRQ_STATE_RESTORER \
323 RESTORE_CALL_CLOBBERED_REGS; \
326 #define IRQ_EXTRA_STATE_SAVER \
327 SAVE_CALL_SAVED_REGS; \
329 #define IRQ_EXTRA_STATE_RESTORER \
330 RESTORE_CALL_SAVED_REGS; \
332 #define IRQ_SCHEDULE_EXTRA_STATE_SAVER /* nothing */
333 #define IRQ_SCHEDULE_EXTRA_STATE_RESTORER /* nothing */
335 /* Register saving/restoring for non-maskable interrupts. */
337 #define NMI_STATE_SAVER \
338 SAVE_CALL_CLOBBERED_REGS; \
341 #define NMI_STATE_RESTORER \
342 RESTORE_CALL_CLOBBERED_REGS; \
345 #define NMI_EXTRA_STATE_SAVER \
346 SAVE_CALL_SAVED_REGS; \
348 #define NMI_EXTRA_STATE_RESTORER \
349 RESTORE_CALL_SAVED_REGS; \
351 #define NMI_SCHEDULE_EXTRA_STATE_SAVER /* nothing */
352 #define NMI_SCHEDULE_EXTRA_STATE_RESTORER /* nothing */
354 /* Register saving/restoring for debug traps. */
355 #define DBTRAP_RET .long 0x014607E0 /* `dbret', but gas doesn't support it. */
356 #define DBTRAP_STATE_SAVER \
357 SAVE_CALL_CLOBBERED_REGS; \
360 #define DBTRAP_STATE_RESTORER \
361 RESTORE_CALL_CLOBBERED_REGS; \
364 #define DBTRAP_EXTRA_STATE_SAVER \
365 SAVE_CALL_SAVED_REGS; \
367 #define DBTRAP_EXTRA_STATE_RESTORER \
368 RESTORE_CALL_SAVED_REGS; \
370 #define DBTRAP_SCHEDULE_EXTRA_STATE_SAVER /* nothing */
371 #define DBTRAP_SCHEDULE_EXTRA_STATE_RESTORER /* nothing */
373 /* Register saving/restoring for a context switch. We don't need to save
374 too many registers, because context-switching looks like a function call
375 (via the function `switch_thread'), so callers will save any
376 call-clobbered registers themselves. We do need to save the CT regs, as
377 they're normally not saved during kernel entry (the kernel doesn't use
378 them). We save PSW so that interrupt-status state will correctly follow
379 each thread (mostly NMI vs. normal-IRQ/trap), though for the most part
380 it doesn't matter since threads are always in almost exactly the same
381 processor state during a context switch. The stack pointer and return
382 value are handled by switch_thread itself. */
383 #define SWITCH_STATE_SAVER \
384 SAVE_CALL_SAVED_REGS; \
387 #define SWITCH_STATE_RESTORER \
388 RESTORE_CALL_SAVED_REGS; \
393 /* Restore register state from the state-save-frame on the stack, switch back
394 to the user stack if necessary, and return from the trap/interrupt.
395 EXTRA_STATE_RESTORER is a sequence of assembly language statements to
396 restore anything not restored by this macro. Only registers not saved by
397 the C compiler are restored (that is, R3(sp), R4(gp), R31(lp), and
398 anything restored by EXTRA_STATE_RESTORER). */
399 #define RETURN(type) \
400 ld.b PTO+PT_KERNEL_MODE[sp], r19; \
401 di; /* Disable interrupts */ \
402 cmp r19, r0; /* See if returning to kernel mode, */\
403 bne 2f; /* ... if so, skip resched &c. */ \
405 /* We're returning to user mode, so check for various conditions that \
406 trigger rescheduling. */ \
407 GET_CURRENT_THREAD(r18); \
408 ld.w TI_FLAGS[r18], r19; \
409 andi _TIF_NEED_RESCHED, r19, r0; \
410 bnz 3f; /* Call the scheduler. */ \
411 5: andi _TIF_SIGPENDING, r19, r18; \
412 ld.w TASK_PTRACE[CURRENT_TASK], r19; /* ptrace flags */ \
413 or r18, r19; /* see if either is non-zero */ \
414 bnz 4f; /* if so, handle them */ \
416 /* Return to user state. */ \
417 1: st.b r0, KM; /* Now officially in user state. */ \
419 /* Final return. The stack-pointer fiddling is not needed when returning \
420 to kernel-mode, but they don't hurt, and this way we can share the \
421 (sometimes rather lengthy) POP_STATE macro. */ \
422 2: POP_STATE(type); \
423 st.w sp, KSP; /* Save the kernel stack pointer. */ \
424 ld.w PT_GPR(GPR_SP)-PT_SIZE[sp], sp; /* Restore stack pointer. */ \
425 type ## _RET; /* Return from the trap/interrupt. */ \
427 /* Call the scheduler before returning from a syscall/trap. */ \
428 3: SAVE_EXTRA_STATE_FOR_SCHEDULE(type); /* Prepare to call scheduler. */ \
429 jarl call_scheduler, lp; /* Call scheduler */ \
430 di; /* The scheduler enables interrupts */\
431 RESTORE_EXTRA_STATE_FOR_SCHEDULE(type); \
432 GET_CURRENT_THREAD(r18); \
433 ld.w TI_FLAGS[r18], r19; \
434 br 5b; /* Continue with return path. */ \
436 /* Handle a signal or ptraced process return. \
437 r18 should be non-zero if there are pending signals. */ \
438 4: /* Not all registers are saved by the normal trap/interrupt entry \
439 points (for instance, call-saved registers (because the normal \
440 C-compiler calling sequence in the kernel makes sure they're \
441 preserved), and call-clobbered registers in the case of \
442 traps), but signal handlers may want to examine or change the \
443 complete register state. Here we save anything not saved by \
444 the normal entry sequence, so that it may be safely restored \
445 (in a possibly modified form) after do_signal returns. */ \
446 SAVE_EXTRA_STATE(type); /* Save state not saved by entry. */ \
447 jarl handle_signal_or_ptrace_return, lp; \
448 RESTORE_EXTRA_STATE(type); /* Restore extra regs. */ \
452 /* Jump to the appropriate function for the system call number in r12
453 (r12 is not preserved), or return an error if r12 is not valid. The
454 LP register should point to the location where the called function
455 should return. [note that MAKE_SYS_CALL uses label 1] */
456 #define MAKE_SYS_CALL \
457 /* Figure out which function to use for this system call. */ \
459 /* See if the system call number is valid. */ \
460 addi lo(CSYM(sys_call_table) - sys_call_table_end), r12, r0; \
462 mov hilo(CSYM(sys_call_table)), r19; \
465 /* Make the system call. */ \
467 /* The syscall number is invalid, return an error. */ \
468 1: addi -ENOSYS, r0, r10; \
477 * Trap 0 system calls are also handled here.
479 * The stack-pointer (r3) should have already been saved to the memory
480 * location ENTRY_SP (the reason for this is that the interrupt vectors may be
481 * beyond a 22-bit signed offset jump from the actual interrupt handler, and
482 * this allows them to save the stack-pointer and use that register to do an
486 * Syscall number in r12, args in r6-r9
487 * Return value in r10
490 SAVE_STATE (TRAP, r12, ENTRY_SP) // Save registers.
491 stsr SR_ECR, r19 // Find out which trap it was.
492 ei // Enable interrupts.
493 mov hilo(ret_from_trap), lp // where the trap should return
495 // The following two shifts (1) clear out extraneous NMI data in the
496 // upper 16-bits, (2) convert the 0x40 - 0x5f range of trap ECR
497 // numbers into the (0-31) << 2 range we want, (3) set the flags.
498 shl 27, r19 // chop off all high bits
499 shr 25, r19 // scale back down and then << 2
500 bnz 2f // See if not trap 0.
502 // Trap 0 is a `short' system call, skip general trap table.
503 MAKE_SYS_CALL // Jump to the syscall function.
505 2: // For other traps, use a table lookup.
506 mov hilo(CSYM(trap_table)), r18
509 jmp [r18] // Jump to the trap handler.
512 /* This is just like ret_from_trap, but first restores extra registers
513 saved by some wrappers. */
514 L_ENTRY(restore_extra_regs_and_ret_from_trap):
515 RESTORE_EXTRA_STATE(TRAP)
517 END(restore_extra_regs_and_ret_from_trap)
519 /* Entry point used to return from a syscall/trap. */
520 L_ENTRY(ret_from_trap):
525 /* This the initial entry point for a new child thread, with an appropriate
526 stack in place that makes it look the the child is in the middle of an
527 syscall. This function is actually `returned to' from switch_thread
528 (copy_thread makes ret_from_fork the return address in each new thread's
530 C_ENTRY(ret_from_fork):
531 mov r10, r6 // switch_thread returns the prev task.
532 jarl CSYM(schedule_tail), lp // ...which is schedule_tail's arg
533 mov r0, r10 // Child's fork call should return 0.
534 br ret_from_trap // Do normal trap return.
539 * Trap 1: `long' system calls
540 * `Long' syscall protocol:
541 * Syscall number in r12, args in r6-r9, r13-r14
542 * Return value in r10
544 L_ENTRY(syscall_long):
545 // Push extra arguments on the stack. Note that by default, the trap
546 // handler reserves enough stack space for 6 arguments, so we don't
547 // have to make any additional room.
548 st.w r13, 16[sp] // arg 5
549 st.w r14, 20[sp] // arg 6
551 // Make sure r13 and r14 are preserved, in case we have to restart a
552 // system call because of a signal (ep has already been set by caller).
553 st.w r13, PTO+PT_GPR(13)[sp]
554 st.w r14, PTO+PT_GPR(13)[sp]
555 mov hilo(ret_from_long_syscall), lp
557 MAKE_SYS_CALL // Jump to the syscall function.
560 /* Entry point used to return from a long syscall. Only needed to restore
561 r13/r14 if the general trap mechanism doesnt' do so. */
562 L_ENTRY(ret_from_long_syscall):
563 ld.w PTO+PT_GPR(13)[sp], r13 // Restore the extra registers
564 ld.w PTO+PT_GPR(13)[sp], r14
565 br ret_from_trap // The rest is the same as other traps
566 END(ret_from_long_syscall)
569 /* These syscalls need access to the struct pt_regs on the stack, so we
570 implement them in assembly (they're basically all wrappers anyway). */
572 L_ENTRY(sys_fork_wrapper):
574 addi SIGCHLD, r0, r6 // Arg 0: flags
575 ld.w PTO+PT_GPR(GPR_SP)[sp], r7 // Arg 1: child SP (use parent's)
576 movea PTO, sp, r8 // Arg 2: parent context
577 mov r0, r9 // Arg 3/4/5: 0
580 mov hilo(CSYM(do_fork)), r18 // Where the real work gets done
581 br save_extra_state_tramp // Save state and go there
583 // fork almost works, enough to trick you into looking elsewhere :-(
584 addi -EINVAL, r0, r10
587 END(sys_fork_wrapper)
589 L_ENTRY(sys_vfork_wrapper):
590 addi CLONE_VFORK | CLONE_VM | SIGCHLD, r0, r6 // Arg 0: flags
591 ld.w PTO+PT_GPR(GPR_SP)[sp], r7 // Arg 1: child SP (use parent's)
592 movea PTO, sp, r8 // Arg 2: parent context
593 mov r0, r9 // Arg 3/4/5: 0
596 mov hilo(CSYM(do_fork)), r18 // Where the real work gets done
597 br save_extra_state_tramp // Save state and go there
598 END(sys_vfork_wrapper)
600 L_ENTRY(sys_clone_wrapper):
601 ld.w PTO+PT_GPR(GPR_SP)[sp], r19// parent's stack pointer
602 cmp r7, r0 // See if child SP arg (arg 1) is 0.
603 cmov z, r19, r7, r7 // ... and use the parent's if so.
604 movea PTO, sp, r8 // Arg 2: parent context
605 mov r0, r9 // Arg 3/4/5: 0
608 mov hilo(CSYM(do_fork)), r18 // Where the real work gets done
609 br save_extra_state_tramp // Save state and go there
610 END(sys_clone_wrapper)
613 L_ENTRY(sys_execve_wrapper):
614 movea PTO, sp, r9 // add user context as 4th arg
615 jr CSYM(sys_execve) // Do real work (tail-call).
616 END(sys_execve_wrapper)
619 L_ENTRY(sys_sigsuspend_wrapper):
620 movea PTO, sp, r7 // add user context as 2nd arg
621 mov hilo(CSYM(sys_sigsuspend)), r18 // syscall function
622 jarl save_extra_state_tramp, lp // Save state and do it
623 br restore_extra_regs_and_ret_from_trap
624 END(sys_sigsuspend_wrapper)
625 L_ENTRY(sys_rt_sigsuspend_wrapper):
626 movea PTO, sp, r8 // add user context as 3rd arg
627 mov hilo(CSYM(sys_rt_sigsuspend)), r18 // syscall function
628 jarl save_extra_state_tramp, lp // Save state and do it
629 br restore_extra_regs_and_ret_from_trap
630 END(sys_rt_sigsuspend_wrapper)
632 L_ENTRY(sys_sigreturn_wrapper):
633 movea PTO, sp, r6 // add user context as 1st arg
634 mov hilo(CSYM(sys_sigreturn)), r18 // syscall function
635 jarl save_extra_state_tramp, lp // Save state and do it
636 br restore_extra_regs_and_ret_from_trap
637 END(sys_sigreturn_wrapper)
638 L_ENTRY(sys_rt_sigreturn_wrapper):
639 movea PTO, sp, r6 // add user context as 1st arg
640 mov hilo(CSYM(sys_rt_sigreturn)), r18// syscall function
641 jarl save_extra_state_tramp, lp // Save state and do it
642 br restore_extra_regs_and_ret_from_trap
643 END(sys_rt_sigreturn_wrapper)
646 /* Save any state not saved by SAVE_STATE(TRAP), and jump to r18.
647 It's main purpose is to share the rather lengthy code sequence that
648 SAVE_STATE expands into among the above wrapper functions. */
649 L_ENTRY(save_extra_state_tramp):
650 SAVE_EXTRA_STATE(TRAP) // Save state not saved by entry.
651 jmp [r18] // Do the work the caller wants
652 END(save_extra_state_tramp)
656 * Hardware maskable interrupts.
658 * The stack-pointer (r3) should have already been saved to the memory
659 * location ENTRY_SP (the reason for this is that the interrupt vectors may be
660 * beyond a 22-bit signed offset jump from the actual interrupt handler, and
661 * this allows them to save the stack-pointer and use that register to do an
665 SAVE_STATE (IRQ, r0, ENTRY_SP) // Save registers.
667 stsr SR_ECR, r6 // Find out which interrupt it was.
668 movea PTO, sp, r7 // User regs are arg2
670 // All v850 implementations I know about encode their interrupts as
671 // multiples of 0x10, starting at 0x80 (after NMIs and software
672 // interrupts). Convert this number into a simple IRQ index for the
673 // rest of the kernel. We also clear the upper 16 bits, which hold
674 // NMI info, and don't appear to be cleared when a NMI returns.
675 shl 16, r6 // clear upper 16 bits
676 shr 20, r6 // shift back, and remove lower nibble
677 add -8, r6 // remove bias for irqs
679 // Call the high-level interrupt handling code.
680 jarl CSYM(handle_irq), lp
687 * Debug trap / illegal-instruction exception
689 * The stack-pointer (r3) should have already been saved to the memory
690 * location ENTRY_SP (the reason for this is that the interrupt vectors may be
691 * beyond a 22-bit signed offset jump from the actual interrupt handler, and
692 * this allows them to save the stack-pointer and use that register to do an
696 SAVE_STATE (DBTRAP, r0, ENTRY_SP)// Save registers.
698 /* First see if we came from kernel mode; if so, the dbtrap
699 instruction has a special meaning, to set the DIR (`debug
700 information register') register. This is because the DIR register
701 can _only_ be manipulated/read while in `debug mode,' and debug
702 mode is only active while we're inside the dbtrap handler. The
703 exact functionality is: { DIR = (DIR | r6) & ~r7; return DIR; }. */
704 ld.b PTO+PT_KERNEL_MODE[sp], r19
713 stsr SR_DIR, r10 // Confirm the value we set
714 st.w r10, PTO+PT_GPR(10)[sp] // return it
717 1: ei // Enable interrupts.
719 /* The default signal type we raise. */
722 /* See if it's a single-step trap. */
724 andi 0x0800, r19, r19
727 /* Look to see if the preceding instruction was is a dbtrap or not,
728 to decide which signal we should use. */
729 stsr SR_DBPC, r19 // PC following trapping insn
731 ori 0xf840, r0, r20 // DBTRAP insn
732 cmp r19, r20 // Was this trap caused by DBTRAP?
733 cmov ne, SIGILL, r6, r6 // Choose signal appropriately
735 /* Raise the desired signal. */
736 2: mov CURRENT_TASK, r7 // Arg 1: task
737 jarl CSYM(send_sig), lp // tail call
744 * Hardware non-maskable interrupts.
746 * The stack-pointer (r3) should have already been saved to the memory
747 * location ENTRY_SP (the reason for this is that the interrupt vectors may be
748 * beyond a 22-bit signed offset jump from the actual interrupt handler, and
749 * this allows them to save the stack-pointer and use that register to do an
753 SAVE_STATE (NMI, r0, NMI_ENTRY_SP); /* Save registers. */
755 stsr SR_ECR, r6; /* Find out which nmi it was. */
756 shr 20, r6; /* Extract NMI code in bits 20-24. */
757 movea PTO, sp, r7; /* User regs are arg2. */
759 /* Non-maskable interrupts always lie right after maskable interrupts.
760 Call the generic IRQ handler, with two arguments, the IRQ number,
761 and a pointer to the user registers, to handle the specifics.
762 (we subtract one because the first NMI has code 1). */
763 addi FIRST_NMI - 1, r6, r6
764 jarl CSYM(handle_irq), lp
771 * Trap with no handler
773 L_ENTRY(bad_trap_wrapper):
774 mov r19, r6 // Arg 0: trap number
775 movea PTO, sp, r7 // Arg 1: user regs
776 jr CSYM(bad_trap) // tail call handler
777 END(bad_trap_wrapper)
781 * Invoke the scheduler, called from the trap/irq kernel exit path.
783 * This basically just calls `schedule', but also arranges for extra
784 * registers to be saved for ptrace'd processes, so ptrace can modify them.
786 L_ENTRY(call_scheduler):
787 ld.w TASK_PTRACE[CURRENT_TASK], r19 // See if task is ptrace'd
789 bnz 1f // ... yes, do special stuff
790 jr CSYM(schedule) // ... no, just tail-call scheduler
792 // Save extra regs for ptrace'd task. We want to save anything
793 // that would otherwise only be `implicitly' saved by the normal
794 // compiler calling-convention.
795 1: mov sp, ep // Setup EP for SAVE_CALL_SAVED_REGS
796 SAVE_CALL_SAVED_REGS // Save call-saved registers to stack
797 mov lp, r20 // Save LP in a callee-saved register
799 jarl CSYM(schedule), lp // Call scheduler
802 mov sp, ep // We can't rely on EP after return
803 RESTORE_CALL_SAVED_REGS // Restore (possibly modified) regs
804 jmp [lp] // Return to the return path
809 * This is an out-of-line handler for two special cases during the kernel
810 * trap/irq exit sequence:
812 * (1) If r18 is non-zero then a signal needs to be handled, which is
813 * done, and then the caller returned to.
815 * (2) If r18 is non-zero then we're returning to a ptraced process, which
816 * has several special cases -- single-stepping and trap tracing, both
817 * of which require using the `dbret' instruction to exit the kernel
818 * instead of the normal `reti' (this is because the CPU not correctly
819 * single-step after a reti). In this case, of course, this handler
820 * never returns to the caller.
822 * In either case, all registers should have been saved to the current
823 * state-save-frame on the stack, except for callee-saved registers.
825 * [These two different cases are combined merely to avoid bloating the
826 * macro-inlined code, not because they really make much sense together!]
828 L_ENTRY(handle_signal_or_ptrace_return):
829 cmp r18, r0 // See if handling a signal
830 bz 1f // ... nope, go do ptrace return
833 mov lp, r20 // Save link-pointer
834 mov r10, r21 // Save return-values (for trap)
837 movea PTO, sp, r6 // Arg 1: struct pt_regs *regs
838 mov r0, r7 // Arg 2: sigset_t *oldset
839 jarl CSYM(do_signal), lp // Handle the signal
840 di // sig handling enables interrupts
842 mov r20, lp // Restore link-pointer
843 mov r21, r10 // Restore return-values (for trap)
845 ld.w TASK_PTRACE[CURRENT_TASK], r19 // check ptrace flags too
847 bnz 1f // ... some set, so look more
848 2: jmp [lp] // ... none set, so return normally
851 1: ld.w PTO+PT_PSW[sp], r19 // Look at user-processes's flags
852 andi 0x0800, r19, r19 // See if single-step flag is set
853 bz 2b // ... nope, return normally
855 // Return as if from a dbtrap insn
856 st.b r0, KM // Now officially in user state.
857 POP_STATE(DBTRAP) // Restore regs
858 st.w sp, KSP // Save the kernel stack pointer.
859 ld.w PT_GPR(GPR_SP)-PT_SIZE[sp], sp // Restore user stack pointer.
860 DBTRAP_RET // Return from the trap/interrupt.
861 END(handle_signal_or_ptrace_return)
865 * This is where we switch between two threads. The arguments are:
866 * r6 -- pointer to the struct thread for the `current' process
867 * r7 -- pointer to the struct thread for the `new' process.
868 * when this function returns, it will return to the new thread.
870 C_ENTRY(switch_thread):
871 // Return the previous task (r10 is not clobbered by restore below)
872 mov CURRENT_TASK, r10
873 // First, push the current processor state on the stack
875 // Now save the location of the kernel stack pointer for this thread;
876 // since we've pushed all other state on the stack, this is enough to
877 // restore it all later.
878 st.w sp, THREAD_KSP[r6]
879 // Now restore the stack pointer from the new process
880 ld.w THREAD_KSP[r7], sp
881 // ... and restore all state from that
883 // Update the current task pointer
884 GET_CURRENT_TASK(CURRENT_TASK)
885 // Now return into the new thread
894 .long bad_trap_wrapper // trap 0, doesn't use trap table.
895 .long syscall_long // trap 1, `long' syscall.
896 .long bad_trap_wrapper
897 .long bad_trap_wrapper
898 .long bad_trap_wrapper
899 .long bad_trap_wrapper
900 .long bad_trap_wrapper
901 .long bad_trap_wrapper
902 .long bad_trap_wrapper
903 .long bad_trap_wrapper
904 .long bad_trap_wrapper
905 .long bad_trap_wrapper
906 .long bad_trap_wrapper
907 .long bad_trap_wrapper
908 .long bad_trap_wrapper
909 .long bad_trap_wrapper
916 C_DATA(sys_call_table):
917 .long CSYM(sys_restart_syscall) // 0
919 .long sys_fork_wrapper
921 .long CSYM(sys_write)
922 .long CSYM(sys_open) // 5
923 .long CSYM(sys_close)
924 .long CSYM(sys_waitpid)
925 .long CSYM(sys_creat)
927 .long CSYM(sys_unlink) // 10
928 .long sys_execve_wrapper
929 .long CSYM(sys_chdir)
931 .long CSYM(sys_mknod)
932 .long CSYM(sys_chmod) // 15
933 .long CSYM(sys_chown)
934 .long CSYM(sys_ni_syscall) // was: break
935 .long CSYM(sys_ni_syscall) // was: oldstat (aka stat)
936 .long CSYM(sys_lseek)
937 .long CSYM(sys_getpid) // 20
938 .long CSYM(sys_mount)
939 .long CSYM(sys_oldumount)
940 .long CSYM(sys_setuid)
941 .long CSYM(sys_getuid)
942 .long CSYM(sys_stime) // 25
943 .long CSYM(sys_ptrace)
944 .long CSYM(sys_alarm)
945 .long CSYM(sys_ni_syscall) // was: oldfstat (aka fstat)
946 .long CSYM(sys_pause)
947 .long CSYM(sys_utime) // 30
948 .long CSYM(sys_ni_syscall) // was: stty
949 .long CSYM(sys_ni_syscall) // was: gtty
950 .long CSYM(sys_access)
952 .long CSYM(sys_ni_syscall) // 35, was: ftime
955 .long CSYM(sys_rename)
956 .long CSYM(sys_mkdir)
957 .long CSYM(sys_rmdir) // 40
960 .long CSYM(sys_times)
961 .long CSYM(sys_ni_syscall) // was: prof
962 .long CSYM(sys_brk) // 45
963 .long CSYM(sys_setgid)
964 .long CSYM(sys_getgid)
965 .long CSYM(sys_signal)
966 .long CSYM(sys_geteuid)
967 .long CSYM(sys_getegid) // 50
969 .long CSYM(sys_umount) // recycled never used phys()
970 .long CSYM(sys_ni_syscall) // was: lock
971 .long CSYM(sys_ioctl)
972 .long CSYM(sys_fcntl) // 55
973 .long CSYM(sys_ni_syscall) // was: mpx
974 .long CSYM(sys_setpgid)
975 .long CSYM(sys_ni_syscall) // was: ulimit
976 .long CSYM(sys_ni_syscall)
977 .long CSYM(sys_umask) // 60
978 .long CSYM(sys_chroot)
979 .long CSYM(sys_ustat)
981 .long CSYM(sys_getppid)
982 .long CSYM(sys_getpgrp) // 65
983 .long CSYM(sys_setsid)
984 .long CSYM(sys_sigaction)
985 .long CSYM(sys_sgetmask)
986 .long CSYM(sys_ssetmask)
987 .long CSYM(sys_setreuid) // 70
988 .long CSYM(sys_setregid)
989 .long sys_sigsuspend_wrapper
990 .long CSYM(sys_sigpending)
991 .long CSYM(sys_sethostname)
992 .long CSYM(sys_setrlimit) // 75
993 .long CSYM(sys_getrlimit)
994 .long CSYM(sys_getrusage)
995 .long CSYM(sys_gettimeofday)
996 .long CSYM(sys_settimeofday)
997 .long CSYM(sys_getgroups) // 80
998 .long CSYM(sys_setgroups)
999 .long CSYM(sys_select)
1000 .long CSYM(sys_symlink)
1001 .long CSYM(sys_ni_syscall) // was: oldlstat (aka lstat)
1002 .long CSYM(sys_readlink) // 85
1003 .long CSYM(sys_uselib)
1004 .long CSYM(sys_swapon)
1005 .long CSYM(sys_reboot)
1006 .long CSYM(old_readdir)
1007 .long CSYM(sys_mmap) // 90
1008 .long CSYM(sys_munmap)
1009 .long CSYM(sys_truncate)
1010 .long CSYM(sys_ftruncate)
1011 .long CSYM(sys_fchmod)
1012 .long CSYM(sys_fchown) // 95
1013 .long CSYM(sys_getpriority)
1014 .long CSYM(sys_setpriority)
1015 .long CSYM(sys_ni_syscall) // was: profil
1016 .long CSYM(sys_statfs)
1017 .long CSYM(sys_fstatfs) // 100
1018 .long CSYM(sys_ni_syscall) // i386: ioperm
1019 .long CSYM(sys_socketcall)
1020 .long CSYM(sys_syslog)
1021 .long CSYM(sys_setitimer)
1022 .long CSYM(sys_getitimer) // 105
1023 .long CSYM(sys_newstat)
1024 .long CSYM(sys_newlstat)
1025 .long CSYM(sys_newfstat)
1026 .long CSYM(sys_ni_syscall) // was: olduname (aka uname)
1027 .long CSYM(sys_ni_syscall) // 110, i386: iopl
1028 .long CSYM(sys_vhangup)
1029 .long CSYM(sys_ni_syscall) // was: idle
1030 .long CSYM(sys_ni_syscall) // i386: vm86old
1031 .long CSYM(sys_wait4)
1032 .long CSYM(sys_swapoff) // 115
1033 .long CSYM(sys_sysinfo)
1035 .long CSYM(sys_fsync)
1036 .long sys_sigreturn_wrapper
1037 .long sys_clone_wrapper // 120
1038 .long CSYM(sys_setdomainname)
1039 .long CSYM(sys_newuname)
1040 .long CSYM(sys_ni_syscall) // i386: modify_ldt, m68k: cacheflush
1041 .long CSYM(sys_adjtimex)
1042 .long CSYM(sys_ni_syscall) // 125 - sys_mprotect
1043 .long CSYM(sys_sigprocmask)
1044 .long CSYM(sys_ni_syscall) // sys_create_module
1045 .long CSYM(sys_init_module)
1046 .long CSYM(sys_delete_module)
1047 .long CSYM(sys_ni_syscall) // 130 - sys_get_kernel_syms
1048 .long CSYM(sys_quotactl)
1049 .long CSYM(sys_getpgid)
1050 .long CSYM(sys_fchdir)
1051 .long CSYM(sys_bdflush)
1052 .long CSYM(sys_sysfs) // 135
1053 .long CSYM(sys_personality)
1054 .long CSYM(sys_ni_syscall) // for afs_syscall
1055 .long CSYM(sys_setfsuid)
1056 .long CSYM(sys_setfsgid)
1057 .long CSYM(sys_llseek) // 140
1058 .long CSYM(sys_getdents)
1059 .long CSYM(sys_select) // for backward compat; remove someday
1060 .long CSYM(sys_flock)
1061 .long CSYM(sys_ni_syscall) // sys_msync
1062 .long CSYM(sys_readv) // 145
1063 .long CSYM(sys_writev)
1064 .long CSYM(sys_getsid)
1065 .long CSYM(sys_fdatasync)
1066 .long CSYM(sys_sysctl)
1067 .long CSYM(sys_ni_syscall) // 150 - sys_mlock
1068 .long CSYM(sys_ni_syscall) // sys_munlock
1069 .long CSYM(sys_ni_syscall) // sys_mlockall
1070 .long CSYM(sys_ni_syscall) // sys_munlockall
1071 .long CSYM(sys_sched_setparam)
1072 .long CSYM(sys_sched_getparam) // 155
1073 .long CSYM(sys_sched_setscheduler)
1074 .long CSYM(sys_sched_getscheduler)
1075 .long CSYM(sys_sched_yield)
1076 .long CSYM(sys_sched_get_priority_max)
1077 .long CSYM(sys_sched_get_priority_min) // 160
1078 .long CSYM(sys_sched_rr_get_interval)
1079 .long CSYM(sys_nanosleep)
1080 .long CSYM(sys_ni_syscall) // sys_mremap
1081 .long CSYM(sys_setresuid)
1082 .long CSYM(sys_getresuid) // 165
1083 .long CSYM(sys_ni_syscall) // for vm86
1084 .long CSYM(sys_ni_syscall) // sys_query_module
1085 .long CSYM(sys_poll)
1086 .long CSYM(sys_nfsservctl)
1087 .long CSYM(sys_setresgid) // 170
1088 .long CSYM(sys_getresgid)
1089 .long CSYM(sys_prctl)
1090 .long sys_rt_sigreturn_wrapper
1091 .long CSYM(sys_rt_sigaction)
1092 .long CSYM(sys_rt_sigprocmask) // 175
1093 .long CSYM(sys_rt_sigpending)
1094 .long CSYM(sys_rt_sigtimedwait)
1095 .long CSYM(sys_rt_sigqueueinfo)
1096 .long sys_rt_sigsuspend_wrapper
1097 .long CSYM(sys_pread64) // 180
1098 .long CSYM(sys_pwrite64)
1099 .long CSYM(sys_lchown)
1100 .long CSYM(sys_getcwd)
1101 .long CSYM(sys_capget)
1102 .long CSYM(sys_capset) // 185
1103 .long CSYM(sys_sigaltstack)
1104 .long CSYM(sys_sendfile)
1105 .long CSYM(sys_ni_syscall) // streams1
1106 .long CSYM(sys_ni_syscall) // streams2
1107 .long sys_vfork_wrapper // 190
1108 .long CSYM(sys_ni_syscall)
1109 .long CSYM(sys_mmap2)
1110 .long CSYM(sys_truncate64)
1111 .long CSYM(sys_ftruncate64)
1112 .long CSYM(sys_stat64) // 195
1113 .long CSYM(sys_lstat64)
1114 .long CSYM(sys_fstat64)
1115 .long CSYM(sys_fcntl64)
1116 .long CSYM(sys_getdents64)
1117 .long CSYM(sys_pivot_root) // 200
1118 .long CSYM(sys_gettid)
1119 .long CSYM(sys_tkill)
1121 C_END(sys_call_table)
projects / linux-2.6 / blob