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1/*
2 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
3 *
4 * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai>
5 * Licensed under the GNU GPL.
6 * thanks to Philipp Rumpf, Mike Shaver and various others
7 * sorry about the wall, puffin..
8 */
9
10#include <asm/asm-offsets.h>
11#include <asm/unistd.h>
12#include <asm/errno.h>
13#include <asm/page.h>
14#include <asm/psw.h>
15#include <asm/thread_info.h>
16#include <asm/assembly.h>
17#include <asm/processor.h>
18
19#include <linux/linkage.h>
20
21 /* We fill the empty parts of the gateway page with
22 * something that will kill the kernel or a
23 * userspace application.
24 */
25#define KILL_INSN break 0,0
26
27 .level LEVEL
28
29 .text
30
31 .import syscall_exit,code
32 .import syscall_exit_rfi,code
33
34 /* Linux gateway page is aliased to virtual page 0 in the kernel
35 * address space. Since it is a gateway page it cannot be
36 * dereferenced, so null pointers will still fault. We start
37 * the actual entry point at 0x100. We put break instructions
38 * at the beginning of the page to trap null indirect function
39 * pointers.
40 */
41
42 .align PAGE_SIZE
43ENTRY(linux_gateway_page)
44
45 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */
46 .rept 44
47 KILL_INSN
48 .endr
49
50 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */
51 /* Light-weight-syscall entry must always be located at 0xb0 */
52 /* WARNING: Keep this number updated with table size changes */
53#define __NR_lws_entries (2)
54
55lws_entry:
56 gate lws_start, %r0 /* increase privilege */
57 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
58
59 /* Fill from 0xb8 to 0xe0 */
60 .rept 10
61 KILL_INSN
62 .endr
63
64 /* This function MUST be located at 0xe0 for glibc's threading
65 mechanism to work. DO NOT MOVE THIS CODE EVER! */
66set_thread_pointer:
67 gate .+8, %r0 /* increase privilege */
68 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
69 be 0(%sr7,%r31) /* return to user space */
70 mtctl %r26, %cr27 /* move arg0 to the control register */
71
72 /* Increase the chance of trapping if random jumps occur to this
73 address, fill from 0xf0 to 0x100 */
74 .rept 4
75 KILL_INSN
76 .endr
77
78/* This address must remain fixed at 0x100 for glibc's syscalls to work */
79 .align 256
80linux_gateway_entry:
81 gate .+8, %r0 /* become privileged */
82 mtsp %r0,%sr4 /* get kernel space into sr4 */
83 mtsp %r0,%sr5 /* get kernel space into sr5 */
84 mtsp %r0,%sr6 /* get kernel space into sr6 */
85 mfsp %sr7,%r1 /* save user sr7 */
86 mtsp %r1,%sr3 /* and store it in sr3 */
87
88#ifdef CONFIG_64BIT
89 /* for now we can *always* set the W bit on entry to the syscall
90 * since we don't support wide userland processes. We could
91 * also save the current SM other than in r0 and restore it on
92 * exit from the syscall, and also use that value to know
93 * whether to do narrow or wide syscalls. -PB
94 */
95 ssm PSW_SM_W, %r1
96 extrd,u %r1,PSW_W_BIT,1,%r1
97 /* sp must be aligned on 4, so deposit the W bit setting into
98 * the bottom of sp temporarily */
99 or,ev %r1,%r30,%r30
100 b,n 1f
101 /* The top halves of argument registers must be cleared on syscall
102 * entry from narrow executable.
103 */
104 depdi 0, 31, 32, %r26
105 depdi 0, 31, 32, %r25
106 depdi 0, 31, 32, %r24
107 depdi 0, 31, 32, %r23
108 depdi 0, 31, 32, %r22
109 depdi 0, 31, 32, %r21
1101:
111#endif
112 mfctl %cr30,%r1
113 xor %r1,%r30,%r30 /* ye olde xor trick */
114 xor %r1,%r30,%r1
115 xor %r1,%r30,%r30
116
117 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */
118
119 /* N.B.: It is critical that we don't set sr7 to 0 until r30
120 * contains a valid kernel stack pointer. It is also
121 * critical that we don't start using the kernel stack
122 * until after sr7 has been set to 0.
123 */
124
125 mtsp %r0,%sr7 /* get kernel space into sr7 */
126 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */
127 mfctl %cr30,%r1 /* get task ptr in %r1 */
128 LDREG TI_TASK(%r1),%r1
129
130 /* Save some registers for sigcontext and potential task
131 switch (see entry.S for the details of which ones are
132 saved/restored). TASK_PT_PSW is zeroed so we can see whether
133 a process is on a syscall or not. For an interrupt the real
134 PSW value is stored. This is needed for gdb and sys_ptrace. */
135 STREG %r0, TASK_PT_PSW(%r1)
136 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */
137 STREG %r19, TASK_PT_GR19(%r1)
138
139 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */
140#ifdef CONFIG_64BIT
141 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */
142#if 0
143 xor %r19,%r2,%r2 /* clear bottom bit */
144 depd,z %r19,1,1,%r19
145 std %r19,TASK_PT_PSW(%r1)
146#endif
147#endif
148 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */
149
150 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */
151 STREG %r21, TASK_PT_GR21(%r1)
152 STREG %r22, TASK_PT_GR22(%r1)
153 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */
154 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */
155 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */
156 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */
157 STREG %r27, TASK_PT_GR27(%r1) /* user dp */
158 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */
159 STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */
160 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */
161 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */
162
163 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */
164 save_fp %r27 /* or potential task switch */
165
166 mfctl %cr11, %r27 /* i.e. SAR */
167 STREG %r27, TASK_PT_SAR(%r1)
168
169 loadgp
170
171#ifdef CONFIG_64BIT
172 ldo -16(%r30),%r29 /* Reference param save area */
173 copy %r19,%r2 /* W bit back to r2 */
174#else
175 /* no need to save these on stack in wide mode because the first 8
176 * args are passed in registers */
177 stw %r22, -52(%r30) /* 5th argument */
178 stw %r21, -56(%r30) /* 6th argument */
179#endif
180
181 /* Are we being ptraced? */
182 mfctl %cr30, %r1
183 LDREG TI_TASK(%r1),%r1
184 ldw TASK_PTRACE(%r1), %r1
185 bb,<,n %r1,31,.Ltracesys
186
187 /* Note! We cannot use the syscall table that is mapped
188 nearby since the gateway page is mapped execute-only. */
189
190#ifdef CONFIG_64BIT
191 ldil L%sys_call_table, %r1
192 or,= %r2,%r2,%r2
193 addil L%(sys_call_table64-sys_call_table), %r1
194 ldo R%sys_call_table(%r1), %r19
195 or,= %r2,%r2,%r2
196 ldo R%sys_call_table64(%r1), %r19
197#else
198 ldil L%sys_call_table, %r1
199 ldo R%sys_call_table(%r1), %r19
200#endif
201 comiclr,>> __NR_Linux_syscalls, %r20, %r0
202 b,n .Lsyscall_nosys
203
204 LDREGX %r20(%r19), %r19
205
206 /* If this is a sys_rt_sigreturn call, and the signal was received
207 * when not in_syscall, then we want to return via syscall_exit_rfi,
208 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
209 * trampoline code in signal.c).
210 */
211 ldi __NR_rt_sigreturn,%r2
212 comb,= %r2,%r20,.Lrt_sigreturn
213.Lin_syscall:
214 ldil L%syscall_exit,%r2
215 be 0(%sr7,%r19)
216 ldo R%syscall_exit(%r2),%r2
217.Lrt_sigreturn:
218 comib,<> 0,%r25,.Lin_syscall
219 ldil L%syscall_exit_rfi,%r2
220 be 0(%sr7,%r19)
221 ldo R%syscall_exit_rfi(%r2),%r2
222
223 /* Note! Because we are not running where we were linked, any
224 calls to functions external to this file must be indirect. To
225 be safe, we apply the opposite rule to functions within this
226 file, with local labels given to them to ensure correctness. */
227
228.Lsyscall_nosys:
229syscall_nosys:
230 ldil L%syscall_exit,%r1
231 be R%syscall_exit(%sr7,%r1)
232 ldo -ENOSYS(%r0),%r28 /* set errno */
233
234
235/* Warning! This trace code is a virtual duplicate of the code above so be
236 * sure to maintain both! */
237.Ltracesys:
238tracesys:
239 /* Need to save more registers so the debugger can see where we
240 * are. This saves only the lower 8 bits of PSW, so that the C
241 * bit is still clear on syscalls, and the D bit is set if this
242 * full register save path has been executed. We check the D
243 * bit on syscall_return_rfi to determine which registers to
244 * restore. An interrupt results in a full PSW saved with the
245 * C bit set, a non-straced syscall entry results in C and D clear
246 * in the saved PSW.
247 */
248 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
249 LDREG TI_TASK(%r1), %r1
250 ssm 0,%r2
251 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */
252 mfsp %sr0,%r2
253 STREG %r2,TASK_PT_SR0(%r1)
254 mfsp %sr1,%r2
255 STREG %r2,TASK_PT_SR1(%r1)
256 mfsp %sr2,%r2
257 STREG %r2,TASK_PT_SR2(%r1)
258 mfsp %sr3,%r2
259 STREG %r2,TASK_PT_SR3(%r1)
260 STREG %r2,TASK_PT_SR4(%r1)
261 STREG %r2,TASK_PT_SR5(%r1)
262 STREG %r2,TASK_PT_SR6(%r1)
263 STREG %r2,TASK_PT_SR7(%r1)
264 STREG %r2,TASK_PT_IASQ0(%r1)
265 STREG %r2,TASK_PT_IASQ1(%r1)
266 LDREG TASK_PT_GR31(%r1),%r2
267 STREG %r2,TASK_PT_IAOQ0(%r1)
268 ldo 4(%r2),%r2
269 STREG %r2,TASK_PT_IAOQ1(%r1)
270 ldo TASK_REGS(%r1),%r2
271 /* reg_save %r2 */
272 STREG %r3,PT_GR3(%r2)
273 STREG %r4,PT_GR4(%r2)
274 STREG %r5,PT_GR5(%r2)
275 STREG %r6,PT_GR6(%r2)
276 STREG %r7,PT_GR7(%r2)
277 STREG %r8,PT_GR8(%r2)
278 STREG %r9,PT_GR9(%r2)
279 STREG %r10,PT_GR10(%r2)
280 STREG %r11,PT_GR11(%r2)
281 STREG %r12,PT_GR12(%r2)
282 STREG %r13,PT_GR13(%r2)
283 STREG %r14,PT_GR14(%r2)
284 STREG %r15,PT_GR15(%r2)
285 STREG %r16,PT_GR16(%r2)
286 STREG %r17,PT_GR17(%r2)
287 STREG %r18,PT_GR18(%r2)
288 /* Finished saving things for the debugger */
289
290 copy %r2,%r26
291 ldil L%do_syscall_trace_enter,%r1
292 ldil L%tracesys_next,%r2
293 be R%do_syscall_trace_enter(%sr7,%r1)
294 ldo R%tracesys_next(%r2),%r2
295
296tracesys_next:
297 /* do_syscall_trace_enter either returned the syscallno, or -1L,
298 * so we skip restoring the PT_GR20 below, since we pulled it from
299 * task->thread.regs.gr[20] above.
300 */
301 copy %ret0,%r20
302 ldil L%sys_call_table,%r1
303 ldo R%sys_call_table(%r1), %r19
304
305 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
306 LDREG TI_TASK(%r1), %r1
307 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */
308 LDREG TASK_PT_GR25(%r1), %r25
309 LDREG TASK_PT_GR24(%r1), %r24
310 LDREG TASK_PT_GR23(%r1), %r23
311#ifdef CONFIG_64BIT
312 LDREG TASK_PT_GR22(%r1), %r22
313 LDREG TASK_PT_GR21(%r1), %r21
314 ldo -16(%r30),%r29 /* Reference param save area */
315#endif
316
317 comiclr,>>= __NR_Linux_syscalls, %r20, %r0
318 b,n .Lsyscall_nosys
319
320 LDREGX %r20(%r19), %r19
321
322 /* If this is a sys_rt_sigreturn call, and the signal was received
323 * when not in_syscall, then we want to return via syscall_exit_rfi,
324 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
325 * trampoline code in signal.c).
326 */
327 ldi __NR_rt_sigreturn,%r2
328 comb,= %r2,%r20,.Ltrace_rt_sigreturn
329.Ltrace_in_syscall:
330 ldil L%tracesys_exit,%r2
331 be 0(%sr7,%r19)
332 ldo R%tracesys_exit(%r2),%r2
333
334 /* Do *not* call this function on the gateway page, because it
335 makes a direct call to syscall_trace. */
336
337tracesys_exit:
338 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
339 LDREG TI_TASK(%r1), %r1
340#ifdef CONFIG_64BIT
341 ldo -16(%r30),%r29 /* Reference param save area */
342#endif
343 ldo TASK_REGS(%r1),%r26
344 bl do_syscall_trace_exit,%r2
345 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */
346 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
347 LDREG TI_TASK(%r1), %r1
348 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */
349
350 ldil L%syscall_exit,%r1
351 be,n R%syscall_exit(%sr7,%r1)
352
353.Ltrace_rt_sigreturn:
354 comib,<> 0,%r25,.Ltrace_in_syscall
355 ldil L%tracesys_sigexit,%r2
356 be 0(%sr7,%r19)
357 ldo R%tracesys_sigexit(%r2),%r2
358
359tracesys_sigexit:
360 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
361 LDREG TI_TASK(%r1), %r1
362#ifdef CONFIG_64BIT
363 ldo -16(%r30),%r29 /* Reference param save area */
364#endif
365 bl do_syscall_trace_exit,%r2
366 ldo TASK_REGS(%r1),%r26
367
368 ldil L%syscall_exit_rfi,%r1
369 be,n R%syscall_exit_rfi(%sr7,%r1)
370
371
372 /*********************************************************
373 32/64-bit Light-Weight-Syscall ABI
374
375 * - Indicates a hint for userspace inline asm
376 implementations.
377
378 Syscall number (caller-saves)
379 - %r20
380 * In asm clobber.
381
382 Argument registers (caller-saves)
383 - %r26, %r25, %r24, %r23, %r22
384 * In asm input.
385
386 Return registers (caller-saves)
387 - %r28 (return), %r21 (errno)
388 * In asm output.
389
390 Caller-saves registers
391 - %r1, %r27, %r29
392 - %r2 (return pointer)
393 - %r31 (ble link register)
394 * In asm clobber.
395
396 Callee-saves registers
397 - %r3-%r18
398 - %r30 (stack pointer)
399 * Not in asm clobber.
400
401 If userspace is 32-bit:
402 Callee-saves registers
403 - %r19 (32-bit PIC register)
404
405 Differences from 32-bit calling convention:
406 - Syscall number in %r20
407 - Additional argument register %r22 (arg4)
408 - Callee-saves %r19.
409
410 If userspace is 64-bit:
411 Callee-saves registers
412 - %r27 (64-bit PIC register)
413
414 Differences from 64-bit calling convention:
415 - Syscall number in %r20
416 - Additional argument register %r22 (arg4)
417 - Callee-saves %r27.
418
419 Error codes returned by entry path:
420
421 ENOSYS - r20 was an invalid LWS number.
422
423 *********************************************************/
424lws_start:
425
426#ifdef CONFIG_64BIT
427 /* FIXME: If we are a 64-bit kernel just
428 * turn this on unconditionally.
429 */
430 ssm PSW_SM_W, %r1
431 extrd,u %r1,PSW_W_BIT,1,%r1
432 /* sp must be aligned on 4, so deposit the W bit setting into
433 * the bottom of sp temporarily */
434 or,ev %r1,%r30,%r30
435
436 /* Clip LWS number to a 32-bit value always */
437 depdi 0, 31, 32, %r20
438#endif
439
440 /* Is the lws entry number valid? */
441 comiclr,>> __NR_lws_entries, %r20, %r0
442 b,n lws_exit_nosys
443
444 /* WARNING: Trashing sr2 and sr3 */
445 mfsp %sr7,%r1 /* get userspace into sr3 */
446 mtsp %r1,%sr3
447 mtsp %r0,%sr2 /* get kernel space into sr2 */
448
449 /* Load table start */
450 ldil L%lws_table, %r1
451 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
452 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */
453
454 /* Jump to lws, lws table pointers already relocated */
455 be,n 0(%sr2,%r21)
456
457lws_exit_nosys:
458 ldo -ENOSYS(%r0),%r21 /* set errno */
459 /* Fall through: Return to userspace */
460
461lws_exit:
462#ifdef CONFIG_64BIT
463 /* decide whether to reset the wide mode bit
464 *
465 * For a syscall, the W bit is stored in the lowest bit
466 * of sp. Extract it and reset W if it is zero */
467 extrd,u,*<> %r30,63,1,%r1
468 rsm PSW_SM_W, %r0
469 /* now reset the lowest bit of sp if it was set */
470 xor %r30,%r1,%r30
471#endif
472 be,n 0(%sr7, %r31)
473
474
475
476 /***************************************************
477 Implementing CAS as an atomic operation:
478
479 %r26 - Address to examine
480 %r25 - Old value to check (old)
481 %r24 - New value to set (new)
482 %r28 - Return prev through this register.
483 %r21 - Kernel error code
484
485 If debugging is DISabled:
486
487 %r21 has the following meanings:
488
489 EAGAIN - CAS is busy, ldcw failed, try again.
490 EFAULT - Read or write failed.
491
492 If debugging is enabled:
493
494 EDEADLOCK - CAS called recursively.
495 EAGAIN && r28 == 1 - CAS is busy. Lock contended.
496 EAGAIN && r28 == 2 - CAS is busy. ldcw failed.
497 EFAULT - Read or write failed.
498
499 Scratch: r20, r28, r1
500
501 ****************************************************/
502
503 /* Do not enable LWS debugging */
504#define ENABLE_LWS_DEBUG 0
505
506 /* ELF64 Process entry path */
507lws_compare_and_swap64:
508#ifdef CONFIG_64BIT
509 b,n lws_compare_and_swap
510#else
511 /* If we are not a 64-bit kernel, then we don't
512 * have 64-bit input registers, and calling
513 * the 64-bit LWS CAS returns ENOSYS.
514 */
515 b,n lws_exit_nosys
516#endif
517
518 /* ELF32 Process entry path */
519lws_compare_and_swap32:
520#ifdef CONFIG_64BIT
521 /* Clip all the input registers */
522 depdi 0, 31, 32, %r26
523 depdi 0, 31, 32, %r25
524 depdi 0, 31, 32, %r24
525#endif
526
527lws_compare_and_swap:
528 /* Load start of lock table */
529 ldil L%lws_lock_start, %r20
530 ldo R%lws_lock_start(%r20), %r28
531
532 /* Extract four bits from r26 and hash lock (Bits 4-7) */
533 extru %r26, 27, 4, %r20
534
535 /* Find lock to use, the hash is either one of 0 to
536 15, multiplied by 16 (keep it 16-byte aligned)
537 and add to the lock table offset. */
538 shlw %r20, 4, %r20
539 add %r20, %r28, %r20
540
541# if ENABLE_LWS_DEBUG
542 /*
543 DEBUG, check for deadlock!
544 If the thread register values are the same
545 then we were the one that locked it last and
546 this is a recurisve call that will deadlock.
547 We *must* giveup this call and fail.
548 */
549 ldw 4(%sr2,%r20), %r28 /* Load thread register */
550 /* WARNING: If cr27 cycles to the same value we have problems */
551 mfctl %cr27, %r21 /* Get current thread register */
552 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */
553 b lws_exit /* Return error! */
554 ldo -EDEADLOCK(%r0), %r21
555cas_lock:
556 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */
557 ldo 1(%r0), %r28 /* 1st case */
558 b lws_exit /* Contended... */
559 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
560cas_nocontend:
561# endif
562/* ENABLE_LWS_DEBUG */
563
564 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
565 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */
566cas_wouldblock:
567 ldo 2(%r0), %r28 /* 2nd case */
568 b lws_exit /* Contended... */
569 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
570
571 /*
572 prev = *addr;
573 if ( prev == old )
574 *addr = new;
575 return prev;
576 */
577
578 /* NOTES:
579 This all works becuse intr_do_signal
580 and schedule both check the return iasq
581 and see that we are on the kernel page
582 so this process is never scheduled off
583 or is ever sent any signal of any sort,
584 thus it is wholly atomic from usrspaces
585 perspective
586 */
587cas_action:
588#if defined CONFIG_SMP && ENABLE_LWS_DEBUG
589 /* DEBUG */
590 mfctl %cr27, %r1
591 stw %r1, 4(%sr2,%r20)
592#endif
593 /* The load and store could fail */
5941: ldw 0(%sr3,%r26), %r28
595 sub,<> %r28, %r25, %r0
5962: stw %r24, 0(%sr3,%r26)
597 /* Free lock */
598 stw %r20, 0(%sr2,%r20)
599#if ENABLE_LWS_DEBUG
600 /* Clear thread register indicator */
601 stw %r0, 4(%sr2,%r20)
602#endif
603 /* Return to userspace, set no error */
604 b lws_exit
605 copy %r0, %r21
606
6073:
608 /* Error occurred on load or store */
609 /* Free lock */
610 stw %r20, 0(%sr2,%r20)
611#if ENABLE_LWS_DEBUG
612 stw %r0, 4(%sr2,%r20)
613#endif
614 b lws_exit
615 ldo -EFAULT(%r0),%r21 /* set errno */
616 nop
617 nop
618 nop
619 nop
620
621 /* Two exception table entries, one for the load,
622 the other for the store. Either return -EFAULT.
623 Each of the entries must be relocated. */
624 .section __ex_table,"aw"
625 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page)
626 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page)
627 .previous
628
629
630 /* Make sure nothing else is placed on this page */
631 .align PAGE_SIZE
632END(linux_gateway_page)
633ENTRY(end_linux_gateway_page)
634
635 /* Relocate symbols assuming linux_gateway_page is mapped
636 to virtual address 0x0 */
637
638#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page)
639
640 .section .rodata,"a"
641
642 .align PAGE_SIZE
643 /* Light-weight-syscall table */
644 /* Start of lws table. */
645ENTRY(lws_table)
646 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */
647 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */
648END(lws_table)
649 /* End of lws table */
650
651 .align PAGE_SIZE
652ENTRY(sys_call_table)
653#include "syscall_table.S"
654END(sys_call_table)
655
656#ifdef CONFIG_64BIT
657 .align PAGE_SIZE
658ENTRY(sys_call_table64)
659#define SYSCALL_TABLE_64BIT
660#include "syscall_table.S"
661END(sys_call_table64)
662#endif
663
664 /*
665 All light-weight-syscall atomic operations
666 will use this set of locks
667
668 NOTE: The lws_lock_start symbol must be
669 at least 16-byte aligned for safe use
670 with ldcw.
671 */
672 .section .data
673 .align PAGE_SIZE
674ENTRY(lws_lock_start)
675 /* lws locks */
676 .rept 16
677 /* Keep locks aligned at 16-bytes */
678 .word 1
679 .word 0
680 .word 0
681 .word 0
682 .endr
683END(lws_lock_start)
684 .previous
685
686.end
687
688
1/*
2 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
3 *
4 * System call entry code / Linux gateway page
5 * Copyright (c) Matthew Wilcox 1999 <willy@infradead.org>
6 * Licensed under the GNU GPL.
7 * thanks to Philipp Rumpf, Mike Shaver and various others
8 * sorry about the wall, puffin..
9 */
10
11/*
12How does the Linux gateway page on PA-RISC work?
13------------------------------------------------
14The Linux gateway page on PA-RISC is "special".
15It actually has PAGE_GATEWAY bits set (this is linux terminology; in parisc
16terminology it's Execute, promote to PL0) in the page map. So anything
17executing on this page executes with kernel level privilege (there's more to it
18than that: to have this happen, you also have to use a branch with a ,gate
19completer to activate the privilege promotion). The upshot is that everything
20that runs on the gateway page runs at kernel privilege but with the current
21user process address space (although you have access to kernel space via %sr2).
22For the 0x100 syscall entry, we redo the space registers to point to the kernel
23address space (preserving the user address space in %sr3), move to wide mode if
24required, save the user registers and branch into the kernel syscall entry
25point. For all the other functions, we execute at kernel privilege but don't
26flip address spaces. The basic upshot of this is that these code snippets are
27executed atomically (because the kernel can't be pre-empted) and they may
28perform architecturally forbidden (to PL3) operations (like setting control
29registers).
30*/
31
32
33#include <asm/asm-offsets.h>
34#include <asm/unistd.h>
35#include <asm/errno.h>
36#include <asm/page.h>
37#include <asm/psw.h>
38#include <asm/thread_info.h>
39#include <asm/assembly.h>
40#include <asm/processor.h>
41#include <asm/cache.h>
42#include <asm/spinlock_types.h>
43
44#include <linux/linkage.h>
45
46 /* We fill the empty parts of the gateway page with
47 * something that will kill the kernel or a
48 * userspace application.
49 */
50#define KILL_INSN break 0,0
51
52 .level PA_ASM_LEVEL
53
54 .macro lws_pagefault_disable reg1,reg2
55 mfctl %cr30, \reg2
56 ldo TASK_PAGEFAULT_DISABLED(\reg2), \reg2
57 ldw 0(%sr2,\reg2), \reg1
58 ldo 1(\reg1), \reg1
59 stw \reg1, 0(%sr2,\reg2)
60 .endm
61
62 .macro lws_pagefault_enable reg1,reg2
63 mfctl %cr30, \reg2
64 ldo TASK_PAGEFAULT_DISABLED(\reg2), \reg2
65 ldw 0(%sr2,\reg2), \reg1
66 ldo -1(\reg1), \reg1
67 stw \reg1, 0(%sr2,\reg2)
68 .endm
69
70 /* raise exception if spinlock content is not zero or
71 * __ARCH_SPIN_LOCK_UNLOCKED_VAL */
72 .macro spinlock_check spin_val,tmpreg
73#ifdef CONFIG_LIGHTWEIGHT_SPINLOCK_CHECK
74 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, \tmpreg
75 andcm,= \spin_val, \tmpreg, %r0
76 .word SPINLOCK_BREAK_INSN
77#endif
78 .endm
79
80 .text
81
82 .import syscall_exit,code
83 .import syscall_exit_rfi,code
84
85 /* Linux gateway page is aliased to virtual page 0 in the kernel
86 * address space. Since it is a gateway page it cannot be
87 * dereferenced, so null pointers will still fault. We start
88 * the actual entry point at 0x100. We put break instructions
89 * at the beginning of the page to trap null indirect function
90 * pointers.
91 */
92
93 .align PAGE_SIZE
94ENTRY(linux_gateway_page)
95
96 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */
97 .rept 44
98 KILL_INSN
99 .endr
100
101 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */
102 /* Light-weight-syscall entry must always be located at 0xb0 */
103 /* WARNING: Keep this number updated with table size changes */
104#define __NR_lws_entries (5)
105
106lws_entry:
107 gate lws_start, %r0 /* increase privilege */
108 depi PRIV_USER, 31, 2, %r31 /* Ensure we return into user mode. */
109
110 /* Fill from 0xb8 to 0xe0 */
111 .rept 10
112 KILL_INSN
113 .endr
114
115 /* This function MUST be located at 0xe0 for glibc's threading
116 mechanism to work. DO NOT MOVE THIS CODE EVER! */
117set_thread_pointer:
118 gate .+8, %r0 /* increase privilege */
119 depi PRIV_USER, 31, 2, %r31 /* Ensure we return into user mode. */
120 be 0(%sr7,%r31) /* return to user space */
121 mtctl %r26, %cr27 /* move arg0 to the control register */
122
123 /* Increase the chance of trapping if random jumps occur to this
124 address, fill from 0xf0 to 0x100 */
125 .rept 4
126 KILL_INSN
127 .endr
128
129/* This address must remain fixed at 0x100 for glibc's syscalls to work */
130 .align LINUX_GATEWAY_ADDR
131linux_gateway_entry:
132 gate .+8, %r0 /* become privileged */
133 mtsp %r0,%sr4 /* get kernel space into sr4 */
134 mtsp %r0,%sr5 /* get kernel space into sr5 */
135 mtsp %r0,%sr6 /* get kernel space into sr6 */
136
137#ifdef CONFIG_64BIT
138 /* Store W bit on entry to the syscall in case it's a wide userland
139 * process. */
140 ssm PSW_SM_W, %r1
141 extrd,u %r1,PSW_W_BIT,1,%r1
142 /* sp must be aligned on 4, so deposit the W bit setting into
143 * the bottom of sp temporarily */
144 or,ev %r1,%r30,%r30
145 b,n 1f
146 /* The top halves of argument registers must be cleared on syscall
147 * entry from narrow executable.
148 */
149 depdi 0, 31, 32, %r26
150 depdi 0, 31, 32, %r25
151 depdi 0, 31, 32, %r24
152 depdi 0, 31, 32, %r23
153 depdi 0, 31, 32, %r22
154 depdi 0, 31, 32, %r21
1551:
156#endif
157
158 /* We use a rsm/ssm pair to prevent sr3 from being clobbered
159 * by external interrupts.
160 */
161 mfsp %sr7,%r1 /* save user sr7 */
162 rsm PSW_SM_I, %r0 /* disable interrupts */
163 mtsp %r1,%sr3 /* and store it in sr3 */
164
165 mfctl %cr30,%r1
166 xor %r1,%r30,%r30 /* ye olde xor trick */
167 xor %r1,%r30,%r1
168 xor %r1,%r30,%r30
169
170 LDREG TASK_STACK(%r30),%r30 /* set up kernel stack */
171 ldo FRAME_SIZE(%r30),%r30
172 /* N.B.: It is critical that we don't set sr7 to 0 until r30
173 * contains a valid kernel stack pointer. It is also
174 * critical that we don't start using the kernel stack
175 * until after sr7 has been set to 0.
176 */
177
178 mtsp %r0,%sr7 /* get kernel space into sr7 */
179 ssm PSW_SM_I, %r0 /* enable interrupts */
180 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */
181 mfctl %cr30,%r1 /* get task ptr in %r1 */
182
183 /* Save some registers for sigcontext and potential task
184 switch (see entry.S for the details of which ones are
185 saved/restored). TASK_PT_PSW is zeroed so we can see whether
186 a process is on a syscall or not. For an interrupt the real
187 PSW value is stored. This is needed for gdb and sys_ptrace. */
188 STREG %r0, TASK_PT_PSW(%r1)
189 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */
190 STREG %r19, TASK_PT_GR19(%r1)
191
192 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */
193#ifdef CONFIG_64BIT
194 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */
195#if 0
196 xor %r19,%r2,%r2 /* clear bottom bit */
197 depd,z %r19,1,1,%r19
198 std %r19,TASK_PT_PSW(%r1)
199#endif
200#endif
201 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */
202
203 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */
204 STREG %r21, TASK_PT_GR21(%r1)
205 STREG %r22, TASK_PT_GR22(%r1)
206 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */
207 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */
208 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */
209 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */
210 STREG %r27, TASK_PT_GR27(%r1) /* user dp */
211 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */
212 STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */
213 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */
214 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */
215
216 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */
217 save_fp %r27 /* or potential task switch */
218
219 mfctl %cr11, %r27 /* i.e. SAR */
220 STREG %r27, TASK_PT_SAR(%r1)
221
222 loadgp
223
224#ifdef CONFIG_64BIT
225 ldo -16(%r30),%r29 /* Reference param save area */
226 copy %r19,%r2 /* W bit back to r2 */
227#else
228 /* no need to save these on stack in wide mode because the first 8
229 * args are passed in registers */
230 stw %r22, -52(%r30) /* 5th argument */
231 stw %r21, -56(%r30) /* 6th argument */
232#endif
233
234 /* Are we being ptraced? */
235 mfctl %cr30, %r1
236 LDREG TASK_TI_FLAGS(%r1),%r1
237 ldi _TIF_SYSCALL_TRACE_MASK, %r19
238 and,COND(=) %r1, %r19, %r0
239 b,n .Ltracesys
240
241 /* Note! We cannot use the syscall table that is mapped
242 nearby since the gateway page is mapped execute-only. */
243
244#ifdef CONFIG_64BIT
245 ldil L%sys_call_table, %r1
246 or,ev %r2,%r2,%r2
247 ldil L%sys_call_table64, %r1
248 ldo R%sys_call_table(%r1), %r19
249 or,ev %r2,%r2,%r2
250 ldo R%sys_call_table64(%r1), %r19
251#else
252 load32 sys_call_table, %r19
253#endif
254 comiclr,>> __NR_Linux_syscalls, %r20, %r0
255 b,n .Lsyscall_nosys
256
257 LDREGX %r20(%r19), %r19
258
259 /* If this is a sys_rt_sigreturn call, and the signal was received
260 * when not in_syscall, then we want to return via syscall_exit_rfi,
261 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
262 * trampoline code in signal.c).
263 */
264 ldi __NR_rt_sigreturn,%r2
265 comb,= %r2,%r20,.Lrt_sigreturn
266.Lin_syscall:
267 ldil L%syscall_exit,%r2
268 be 0(%sr7,%r19)
269 ldo R%syscall_exit(%r2),%r2
270.Lrt_sigreturn:
271 comib,<> 0,%r25,.Lin_syscall
272 ldil L%syscall_exit_rfi,%r2
273 be 0(%sr7,%r19)
274 ldo R%syscall_exit_rfi(%r2),%r2
275
276 /* Note! Because we are not running where we were linked, any
277 calls to functions external to this file must be indirect. To
278 be safe, we apply the opposite rule to functions within this
279 file, with local labels given to them to ensure correctness. */
280
281.Lsyscall_nosys:
282syscall_nosys:
283 ldil L%syscall_exit,%r1
284 be R%syscall_exit(%sr7,%r1)
285 ldo -ENOSYS(%r0),%r28 /* set errno */
286
287
288/* Warning! This trace code is a virtual duplicate of the code above so be
289 * sure to maintain both! */
290.Ltracesys:
291tracesys:
292 /* Need to save more registers so the debugger can see where we
293 * are. This saves only the lower 8 bits of PSW, so that the C
294 * bit is still clear on syscalls, and the D bit is set if this
295 * full register save path has been executed. We check the D
296 * bit on syscall_return_rfi to determine which registers to
297 * restore. An interrupt results in a full PSW saved with the
298 * C bit set, a non-straced syscall entry results in C and D clear
299 * in the saved PSW.
300 */
301 mfctl %cr30,%r1 /* get task ptr */
302 ssm 0,%r2
303 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */
304 mfsp %sr0,%r2
305 STREG %r2,TASK_PT_SR0(%r1)
306 mfsp %sr1,%r2
307 STREG %r2,TASK_PT_SR1(%r1)
308 mfsp %sr2,%r2
309 STREG %r2,TASK_PT_SR2(%r1)
310 mfsp %sr3,%r2
311 STREG %r2,TASK_PT_SR3(%r1)
312 STREG %r2,TASK_PT_SR4(%r1)
313 STREG %r2,TASK_PT_SR5(%r1)
314 STREG %r2,TASK_PT_SR6(%r1)
315 STREG %r2,TASK_PT_SR7(%r1)
316 STREG %r2,TASK_PT_IASQ0(%r1)
317 STREG %r2,TASK_PT_IASQ1(%r1)
318 LDREG TASK_PT_GR31(%r1),%r2
319 STREG %r2,TASK_PT_IAOQ0(%r1)
320 ldo 4(%r2),%r2
321 STREG %r2,TASK_PT_IAOQ1(%r1)
322 ldo TASK_REGS(%r1),%r2
323 /* reg_save %r2 */
324 STREG %r3,PT_GR3(%r2)
325 STREG %r4,PT_GR4(%r2)
326 STREG %r5,PT_GR5(%r2)
327 STREG %r6,PT_GR6(%r2)
328 STREG %r7,PT_GR7(%r2)
329 STREG %r8,PT_GR8(%r2)
330 STREG %r9,PT_GR9(%r2)
331 STREG %r10,PT_GR10(%r2)
332 STREG %r11,PT_GR11(%r2)
333 STREG %r12,PT_GR12(%r2)
334 STREG %r13,PT_GR13(%r2)
335 STREG %r14,PT_GR14(%r2)
336 STREG %r15,PT_GR15(%r2)
337 STREG %r16,PT_GR16(%r2)
338 STREG %r17,PT_GR17(%r2)
339 STREG %r18,PT_GR18(%r2)
340 /* Finished saving things for the debugger */
341
342 copy %r2,%r26
343 ldil L%do_syscall_trace_enter,%r1
344 ldil L%tracesys_next,%r2
345 be R%do_syscall_trace_enter(%sr7,%r1)
346 ldo R%tracesys_next(%r2),%r2
347
348tracesys_next:
349 /* do_syscall_trace_enter either returned the syscallno, or -1L,
350 * so we skip restoring the PT_GR20 below, since we pulled it from
351 * task->thread.regs.gr[20] above.
352 */
353 copy %ret0,%r20
354
355 mfctl %cr30,%r1 /* get task ptr */
356 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return value */
357 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */
358 LDREG TASK_PT_GR25(%r1), %r25
359 LDREG TASK_PT_GR24(%r1), %r24
360 LDREG TASK_PT_GR23(%r1), %r23
361 LDREG TASK_PT_GR22(%r1), %r22
362 LDREG TASK_PT_GR21(%r1), %r21
363#ifdef CONFIG_64BIT
364 ldo -16(%r30),%r29 /* Reference param save area */
365#else
366 stw %r22, -52(%r30) /* 5th argument */
367 stw %r21, -56(%r30) /* 6th argument */
368#endif
369
370 cmpib,COND(=),n -1,%r20,tracesys_exit /* seccomp may have returned -1 */
371 comiclr,>> __NR_Linux_syscalls, %r20, %r0
372 b,n .Ltracesys_nosys
373
374 /* Note! We cannot use the syscall table that is mapped
375 nearby since the gateway page is mapped execute-only. */
376
377#ifdef CONFIG_64BIT
378 LDREG TASK_PT_GR30(%r1), %r19 /* get users sp back */
379 extrd,u %r19,63,1,%r2 /* W hidden in bottom bit */
380
381 ldil L%sys_call_table, %r1
382 or,ev %r2,%r2,%r2
383 ldil L%sys_call_table64, %r1
384 ldo R%sys_call_table(%r1), %r19
385 or,ev %r2,%r2,%r2
386 ldo R%sys_call_table64(%r1), %r19
387#else
388 load32 sys_call_table, %r19
389#endif
390
391 LDREGX %r20(%r19), %r19
392
393 /* If this is a sys_rt_sigreturn call, and the signal was received
394 * when not in_syscall, then we want to return via syscall_exit_rfi,
395 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
396 * trampoline code in signal.c).
397 */
398 ldi __NR_rt_sigreturn,%r2
399 comb,= %r2,%r20,.Ltrace_rt_sigreturn
400.Ltrace_in_syscall:
401 ldil L%tracesys_exit,%r2
402 be 0(%sr7,%r19)
403 ldo R%tracesys_exit(%r2),%r2
404
405.Ltracesys_nosys:
406 ldo -ENOSYS(%r0),%r28 /* set errno */
407
408 /* Do *not* call this function on the gateway page, because it
409 makes a direct call to syscall_trace. */
410
411tracesys_exit:
412 mfctl %cr30,%r1 /* get task ptr */
413#ifdef CONFIG_64BIT
414 ldo -16(%r30),%r29 /* Reference param save area */
415#endif
416 ldo TASK_REGS(%r1),%r26
417 BL do_syscall_trace_exit,%r2
418 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */
419 mfctl %cr30,%r1 /* get task ptr */
420 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */
421
422 ldil L%syscall_exit,%r1
423 be,n R%syscall_exit(%sr7,%r1)
424
425.Ltrace_rt_sigreturn:
426 comib,<> 0,%r25,.Ltrace_in_syscall
427 ldil L%tracesys_sigexit,%r2
428 be 0(%sr7,%r19)
429 ldo R%tracesys_sigexit(%r2),%r2
430
431tracesys_sigexit:
432 mfctl %cr30,%r1 /* get task ptr */
433#ifdef CONFIG_64BIT
434 ldo -16(%r30),%r29 /* Reference param save area */
435#endif
436 BL do_syscall_trace_exit,%r2
437 ldo TASK_REGS(%r1),%r26
438
439 ldil L%syscall_exit_rfi,%r1
440 be,n R%syscall_exit_rfi(%sr7,%r1)
441
442
443 /*********************************************************
444 32/64-bit Light-Weight-Syscall ABI
445
446 * - Indicates a hint for userspace inline asm
447 implementations.
448
449 Syscall number (caller-saves)
450 - %r20
451 * In asm clobber.
452
453 Argument registers (caller-saves)
454 - %r26, %r25, %r24, %r23, %r22
455 * In asm input.
456
457 Return registers (caller-saves)
458 - %r28 (return), %r21 (errno)
459 * In asm output.
460
461 Caller-saves registers
462 - %r1, %r27, %r29
463 - %r2 (return pointer)
464 - %r31 (ble link register)
465 * In asm clobber.
466
467 Callee-saves registers
468 - %r3-%r18
469 - %r30 (stack pointer)
470 * Not in asm clobber.
471
472 If userspace is 32-bit:
473 Callee-saves registers
474 - %r19 (32-bit PIC register)
475
476 Differences from 32-bit calling convention:
477 - Syscall number in %r20
478 - Additional argument register %r22 (arg4)
479 - Callee-saves %r19.
480
481 If userspace is 64-bit:
482 Callee-saves registers
483 - %r27 (64-bit PIC register)
484
485 Differences from 64-bit calling convention:
486 - Syscall number in %r20
487 - Additional argument register %r22 (arg4)
488 - Callee-saves %r27.
489
490 Error codes returned by entry path:
491
492 ENOSYS - r20 was an invalid LWS number.
493
494 *********************************************************/
495lws_start:
496
497#ifdef CONFIG_64BIT
498 ssm PSW_SM_W, %r1
499 extrd,u %r1,PSW_W_BIT,1,%r1
500 /* sp must be aligned on 4, so deposit the W bit setting into
501 * the bottom of sp temporarily */
502 or,od %r1,%r30,%r30
503
504 /* Clip LWS number to a 32-bit value for 32-bit processes */
505 depdi 0, 31, 32, %r20
506#endif
507
508 /* Is the lws entry number valid? */
509 comiclr,>> __NR_lws_entries, %r20, %r0
510 b,n lws_exit_nosys
511
512 /* Load table start */
513 ldil L%lws_table, %r1
514 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
515 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */
516
517 /* Jump to lws, lws table pointers already relocated */
518 be,n 0(%sr2,%r21)
519
520lws_exit_noerror:
521 lws_pagefault_enable %r1,%r21
522 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, %r21
523 stw,ma %r21, 0(%sr2,%r20)
524 ssm PSW_SM_I, %r0
525 b lws_exit
526 copy %r0, %r21
527
528lws_wouldblock:
529 ssm PSW_SM_I, %r0
530 ldo 2(%r0), %r28
531 b lws_exit
532 ldo -EAGAIN(%r0), %r21
533
534lws_pagefault:
535 lws_pagefault_enable %r1,%r21
536 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, %r21
537 stw,ma %r21, 0(%sr2,%r20)
538 ssm PSW_SM_I, %r0
539 ldo 3(%r0),%r28
540 b lws_exit
541 ldo -EAGAIN(%r0),%r21
542
543lws_fault:
544 ldo 1(%r0),%r28
545 b lws_exit
546 ldo -EFAULT(%r0),%r21
547
548lws_exit_nosys:
549 ldo -ENOSYS(%r0),%r21
550 /* Fall through: Return to userspace */
551
552lws_exit:
553#ifdef CONFIG_64BIT
554 /* decide whether to reset the wide mode bit
555 *
556 * For a syscall, the W bit is stored in the lowest bit
557 * of sp. Extract it and reset W if it is zero */
558 extrd,u,*<> %r30,63,1,%r1
559 rsm PSW_SM_W, %r0
560 /* now reset the lowest bit of sp if it was set */
561 xor %r30,%r1,%r30
562#endif
563 be,n 0(%sr7, %r31)
564
565
566
567 /***************************************************
568 Implementing 32bit CAS as an atomic operation:
569
570 %r26 - Address to examine
571 %r25 - Old value to check (old)
572 %r24 - New value to set (new)
573 %r28 - Return prev through this register.
574 %r21 - Kernel error code
575
576 %r21 returns the following error codes:
577 EAGAIN - CAS is busy, ldcw failed, try again.
578 EFAULT - Read or write failed.
579
580 If EAGAIN is returned, %r28 indicates the busy reason:
581 r28 == 1 - CAS is busy. lock contended.
582 r28 == 2 - CAS is busy. ldcw failed.
583 r28 == 3 - CAS is busy. page fault.
584
585 Scratch: r20, r28, r1
586
587 ****************************************************/
588
589 /* ELF64 Process entry path */
590lws_compare_and_swap64:
591#ifdef CONFIG_64BIT
592 b,n lws_compare_and_swap
593#else
594 /* If we are not a 64-bit kernel, then we don't
595 * have 64-bit input registers, and calling
596 * the 64-bit LWS CAS returns ENOSYS.
597 */
598 b,n lws_exit_nosys
599#endif
600
601 /* ELF32/ELF64 Process entry path */
602lws_compare_and_swap32:
603#ifdef CONFIG_64BIT
604 /* Wide mode user process? */
605 bb,<,n %sp, 31, lws_compare_and_swap
606
607 /* Clip all the input registers for 32-bit processes */
608 depdi 0, 31, 32, %r26
609 depdi 0, 31, 32, %r25
610 depdi 0, 31, 32, %r24
611#endif
612
613lws_compare_and_swap:
614 /* Trigger memory reference interruptions without writing to memory */
6151: ldw 0(%r26), %r28
6162: stbys,e %r0, 0(%r26)
617
618 /* Calculate 8-bit hash index from virtual address */
619 extru_safe %r26, 27, 8, %r20
620
621 /* Load start of lock table */
622 ldil L%lws_lock_start, %r28
623 ldo R%lws_lock_start(%r28), %r28
624
625 /* Find lock to use, the hash index is one of 0 to
626 255, multiplied by 16 (keep it 16-byte aligned)
627 and add to the lock table offset. */
628 shlw %r20, 4, %r20
629 add %r20, %r28, %r20
630
631 rsm PSW_SM_I, %r0 /* Disable interrupts */
632
633 /* Try to acquire the lock */
634 LDCW 0(%sr2,%r20), %r28
635 spinlock_check %r28, %r21
636 comclr,<> %r0, %r28, %r0
637 b,n lws_wouldblock
638
639 /* Disable page faults to prevent sleeping in critical region */
640 lws_pagefault_disable %r21,%r28
641
642 /*
643 prev = *addr;
644 if ( prev == old )
645 *addr = new;
646 return prev;
647 */
648
649 /* NOTES:
650 This all works because intr_do_signal
651 and schedule both check the return iasq
652 and see that we are on the kernel page
653 so this process is never scheduled off
654 or is ever sent any signal of any sort,
655 thus it is wholly atomic from usrspace's
656 perspective
657 */
658 /* The load and store could fail */
6593: ldw 0(%r26), %r28
660 sub,<> %r28, %r25, %r0
6614: stw %r24, 0(%r26)
662 b,n lws_exit_noerror
663
664 /* A fault occurred on load or stbys,e store */
6655: b,n lws_fault
666 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 5b-linux_gateway_page)
667 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 5b-linux_gateway_page)
668
669 /* A page fault occurred in critical region */
6706: b,n lws_pagefault
671 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 6b-linux_gateway_page)
672 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 6b-linux_gateway_page)
673
674
675 /***************************************************
676 New CAS implementation which uses pointers and variable size
677 information. The value pointed by old and new MUST NOT change
678 while performing CAS. The lock only protects the value at %r26.
679
680 %r26 - Address to examine
681 %r25 - Pointer to the value to check (old)
682 %r24 - Pointer to the value to set (new)
683 %r23 - Size of the variable (0/1/2/3 for 8/16/32/64 bit)
684 %r28 - Return non-zero on failure
685 %r21 - Kernel error code
686
687 %r21 returns the following error codes:
688 EAGAIN - CAS is busy, ldcw failed, try again.
689 EFAULT - Read or write failed.
690
691 If EAGAIN is returned, %r28 indicates the busy reason:
692 r28 == 1 - CAS is busy. lock contended.
693 r28 == 2 - CAS is busy. ldcw failed.
694 r28 == 3 - CAS is busy. page fault.
695
696 Scratch: r20, r22, r28, r29, r1, fr4 (32bit for 64bit CAS only)
697
698 ****************************************************/
699
700lws_compare_and_swap_2:
701#ifdef CONFIG_64BIT
702 /* Wide mode user process? */
703 bb,<,n %sp, 31, cas2_begin
704
705 /* Clip the input registers for 32-bit processes. We don't
706 need to clip %r23 as we only use it for word operations */
707 depdi 0, 31, 32, %r26
708 depdi 0, 31, 32, %r25
709 depdi 0, 31, 32, %r24
710#endif
711
712cas2_begin:
713 /* Check the validity of the size pointer */
714 subi,>>= 3, %r23, %r0
715 b,n lws_exit_nosys
716
717 /* Jump to the functions which will load the old and new values into
718 registers depending on the their size */
719 shlw %r23, 2, %r29
720 blr %r29, %r0
721 nop
722
723 /* 8-bit load */
7241: ldb 0(%r25), %r25
725 b cas2_lock_start
7262: ldb 0(%r24), %r24
727 nop
728 nop
729 nop
730 nop
731 nop
732
733 /* 16-bit load */
7343: ldh 0(%r25), %r25
735 b cas2_lock_start
7364: ldh 0(%r24), %r24
737 nop
738 nop
739 nop
740 nop
741 nop
742
743 /* 32-bit load */
7445: ldw 0(%r25), %r25
745 b cas2_lock_start
7466: ldw 0(%r24), %r24
747 nop
748 nop
749 nop
750 nop
751 nop
752
753 /* 64-bit load */
754#ifdef CONFIG_64BIT
7557: ldd 0(%r25), %r25
7568: ldd 0(%r24), %r24
757#else
758 /* Load old value into r22/r23 - high/low */
7597: ldw 0(%r25), %r22
7608: ldw 4(%r25), %r23
761 /* Load new value into fr4 for atomic store later */
7629: flddx 0(%r24), %fr4
763#endif
764
765cas2_lock_start:
766 /* Trigger memory reference interruptions without writing to memory */
767 copy %r26, %r28
768 depi_safe 0, 31, 2, %r28
76910: ldw 0(%r28), %r1
77011: stbys,e %r0, 0(%r28)
771
772 /* Calculate 8-bit hash index from virtual address */
773 extru_safe %r26, 27, 8, %r20
774
775 /* Load start of lock table */
776 ldil L%lws_lock_start, %r28
777 ldo R%lws_lock_start(%r28), %r28
778
779 /* Find lock to use, the hash index is one of 0 to
780 255, multiplied by 16 (keep it 16-byte aligned)
781 and add to the lock table offset. */
782 shlw %r20, 4, %r20
783 add %r20, %r28, %r20
784
785 rsm PSW_SM_I, %r0 /* Disable interrupts */
786
787 /* Try to acquire the lock */
788 LDCW 0(%sr2,%r20), %r28
789 spinlock_check %r28, %r21
790 comclr,<> %r0, %r28, %r0
791 b,n lws_wouldblock
792
793 /* Disable page faults to prevent sleeping in critical region */
794 lws_pagefault_disable %r21,%r28
795
796 /*
797 prev = *addr;
798 if ( prev == old )
799 *addr = new;
800 return prev;
801 */
802
803 /* NOTES:
804 This all works because intr_do_signal
805 and schedule both check the return iasq
806 and see that we are on the kernel page
807 so this process is never scheduled off
808 or is ever sent any signal of any sort,
809 thus it is wholly atomic from usrspace's
810 perspective
811 */
812
813 /* Jump to the correct function */
814 blr %r29, %r0
815 /* Set %r28 as non-zero for now */
816 ldo 1(%r0),%r28
817
818 /* 8-bit CAS */
81912: ldb 0(%r26), %r29
820 sub,= %r29, %r25, %r0
821 b,n lws_exit_noerror
82213: stb %r24, 0(%r26)
823 b lws_exit_noerror
824 copy %r0, %r28
825 nop
826 nop
827
828 /* 16-bit CAS */
82914: ldh 0(%r26), %r29
830 sub,= %r29, %r25, %r0
831 b,n lws_exit_noerror
83215: sth %r24, 0(%r26)
833 b lws_exit_noerror
834 copy %r0, %r28
835 nop
836 nop
837
838 /* 32-bit CAS */
83916: ldw 0(%r26), %r29
840 sub,= %r29, %r25, %r0
841 b,n lws_exit_noerror
84217: stw %r24, 0(%r26)
843 b lws_exit_noerror
844 copy %r0, %r28
845 nop
846 nop
847
848 /* 64-bit CAS */
849#ifdef CONFIG_64BIT
85018: ldd 0(%r26), %r29
851 sub,*= %r29, %r25, %r0
852 b,n lws_exit_noerror
85319: std %r24, 0(%r26)
854 copy %r0, %r28
855#else
856 /* Compare first word */
85718: ldw 0(%r26), %r29
858 sub,= %r29, %r22, %r0
859 b,n lws_exit_noerror
860 /* Compare second word */
86119: ldw 4(%r26), %r29
862 sub,= %r29, %r23, %r0
863 b,n lws_exit_noerror
864 /* Perform the store */
86520: fstdx %fr4, 0(%r26)
866 copy %r0, %r28
867#endif
868 b lws_exit_noerror
869 copy %r0, %r28
870
871 /* A fault occurred on load or stbys,e store */
87230: b,n lws_fault
873 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page)
874 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page)
875 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page)
876 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page)
877 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page)
878 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page)
879 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page)
880 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 30b-linux_gateway_page)
881#ifndef CONFIG_64BIT
882 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 30b-linux_gateway_page)
883#endif
884
885 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 30b-linux_gateway_page)
886 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 30b-linux_gateway_page)
887
888 /* A page fault occurred in critical region */
88931: b,n lws_pagefault
890 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 31b-linux_gateway_page)
891 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 31b-linux_gateway_page)
892 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page)
893 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page)
894 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page)
895 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 31b-linux_gateway_page)
896 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 31b-linux_gateway_page)
897 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 31b-linux_gateway_page)
898#ifndef CONFIG_64BIT
899 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 31b-linux_gateway_page)
900#endif
901
902
903 /***************************************************
904 LWS atomic exchange.
905
906 %r26 - Exchange address
907 %r25 - Size of the variable (0/1/2/3 for 8/16/32/64 bit)
908 %r24 - Address of new value
909 %r23 - Address of old value
910 %r28 - Return non-zero on failure
911 %r21 - Kernel error code
912
913 %r21 returns the following error codes:
914 EAGAIN - CAS is busy, ldcw failed, try again.
915 EFAULT - Read or write failed.
916
917 If EAGAIN is returned, %r28 indicates the busy reason:
918 r28 == 1 - CAS is busy. lock contended.
919 r28 == 2 - CAS is busy. ldcw failed.
920 r28 == 3 - CAS is busy. page fault.
921
922 Scratch: r20, r1
923
924 ****************************************************/
925
926lws_atomic_xchg:
927#ifdef CONFIG_64BIT
928 /* Wide mode user process? */
929 bb,<,n %sp, 31, atomic_xchg_begin
930
931 /* Clip the input registers for 32-bit processes. We don't
932 need to clip %r23 as we only use it for word operations */
933 depdi 0, 31, 32, %r26
934 depdi 0, 31, 32, %r25
935 depdi 0, 31, 32, %r24
936 depdi 0, 31, 32, %r23
937#endif
938
939atomic_xchg_begin:
940 /* Check the validity of the size pointer */
941 subi,>>= 3, %r25, %r0
942 b,n lws_exit_nosys
943
944 /* Jump to the functions which will load the old and new values into
945 registers depending on the their size */
946 shlw %r25, 2, %r1
947 blr %r1, %r0
948 nop
949
950 /* Perform exception checks */
951
952 /* 8-bit exchange */
9531: ldb 0(%r24), %r20
954 copy %r23, %r20
955 depi_safe 0, 31, 2, %r20
956 b atomic_xchg_start
9572: stbys,e %r0, 0(%r20)
958 nop
959 nop
960 nop
961
962 /* 16-bit exchange */
9633: ldh 0(%r24), %r20
964 copy %r23, %r20
965 depi_safe 0, 31, 2, %r20
966 b atomic_xchg_start
9674: stbys,e %r0, 0(%r20)
968 nop
969 nop
970 nop
971
972 /* 32-bit exchange */
9735: ldw 0(%r24), %r20
974 b atomic_xchg_start
9756: stbys,e %r0, 0(%r23)
976 nop
977 nop
978 nop
979 nop
980 nop
981
982 /* 64-bit exchange */
983#ifdef CONFIG_64BIT
9847: ldd 0(%r24), %r20
9858: stdby,e %r0, 0(%r23)
986#else
9877: ldw 0(%r24), %r20
9888: ldw 4(%r24), %r20
989 copy %r23, %r20
990 depi_safe 0, 31, 2, %r20
9919: stbys,e %r0, 0(%r20)
99210: stbys,e %r0, 4(%r20)
993#endif
994
995atomic_xchg_start:
996 /* Trigger memory reference interruptions without writing to memory */
997 copy %r26, %r28
998 depi_safe 0, 31, 2, %r28
99911: ldw 0(%r28), %r1
100012: stbys,e %r0, 0(%r28)
1001
1002 /* Calculate 8-bit hash index from virtual address */
1003 extru_safe %r26, 27, 8, %r20
1004
1005 /* Load start of lock table */
1006 ldil L%lws_lock_start, %r28
1007 ldo R%lws_lock_start(%r28), %r28
1008
1009 /* Find lock to use, the hash index is one of 0 to
1010 255, multiplied by 16 (keep it 16-byte aligned)
1011 and add to the lock table offset. */
1012 shlw %r20, 4, %r20
1013 add %r20, %r28, %r20
1014
1015 rsm PSW_SM_I, %r0 /* Disable interrupts */
1016
1017 /* Try to acquire the lock */
1018 LDCW 0(%sr2,%r20), %r28
1019 spinlock_check %r28, %r21
1020 comclr,<> %r0, %r28, %r0
1021 b,n lws_wouldblock
1022
1023 /* Disable page faults to prevent sleeping in critical region */
1024 lws_pagefault_disable %r21,%r28
1025
1026 /* NOTES:
1027 This all works because intr_do_signal
1028 and schedule both check the return iasq
1029 and see that we are on the kernel page
1030 so this process is never scheduled off
1031 or is ever sent any signal of any sort,
1032 thus it is wholly atomic from userspace's
1033 perspective
1034 */
1035
1036 /* Jump to the correct function */
1037 blr %r1, %r0
1038 /* Set %r28 as non-zero for now */
1039 ldo 1(%r0),%r28
1040
1041 /* 8-bit exchange */
104214: ldb 0(%r26), %r1
104315: stb %r1, 0(%r23)
104415: ldb 0(%r24), %r1
104517: stb %r1, 0(%r26)
1046 b lws_exit_noerror
1047 copy %r0, %r28
1048 nop
1049 nop
1050
1051 /* 16-bit exchange */
105218: ldh 0(%r26), %r1
105319: sth %r1, 0(%r23)
105420: ldh 0(%r24), %r1
105521: sth %r1, 0(%r26)
1056 b lws_exit_noerror
1057 copy %r0, %r28
1058 nop
1059 nop
1060
1061 /* 32-bit exchange */
106222: ldw 0(%r26), %r1
106323: stw %r1, 0(%r23)
106424: ldw 0(%r24), %r1
106525: stw %r1, 0(%r26)
1066 b lws_exit_noerror
1067 copy %r0, %r28
1068 nop
1069 nop
1070
1071 /* 64-bit exchange */
1072#ifdef CONFIG_64BIT
107326: ldd 0(%r26), %r1
107427: std %r1, 0(%r23)
107528: ldd 0(%r24), %r1
107629: std %r1, 0(%r26)
1077#else
107826: flddx 0(%r26), %fr4
107927: fstdx %fr4, 0(%r23)
108028: flddx 0(%r24), %fr4
108129: fstdx %fr4, 0(%r26)
1082#endif
1083 b lws_exit_noerror
1084 copy %r0, %r28
1085
1086 /* A fault occurred on load or stbys,e store */
108730: b,n lws_fault
1088 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page)
1089 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page)
1090 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page)
1091 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page)
1092 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page)
1093 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page)
1094 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page)
1095 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 30b-linux_gateway_page)
1096#ifndef CONFIG_64BIT
1097 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 30b-linux_gateway_page)
1098 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 30b-linux_gateway_page)
1099#endif
1100
1101 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 30b-linux_gateway_page)
1102 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 30b-linux_gateway_page)
1103
1104 /* A page fault occurred in critical region */
110531: b,n lws_pagefault
1106 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page)
1107 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page)
1108 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page)
1109 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 31b-linux_gateway_page)
1110 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 31b-linux_gateway_page)
1111 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 31b-linux_gateway_page)
1112 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 31b-linux_gateway_page)
1113 ASM_EXCEPTIONTABLE_ENTRY(21b-linux_gateway_page, 31b-linux_gateway_page)
1114 ASM_EXCEPTIONTABLE_ENTRY(22b-linux_gateway_page, 31b-linux_gateway_page)
1115 ASM_EXCEPTIONTABLE_ENTRY(23b-linux_gateway_page, 31b-linux_gateway_page)
1116 ASM_EXCEPTIONTABLE_ENTRY(24b-linux_gateway_page, 31b-linux_gateway_page)
1117 ASM_EXCEPTIONTABLE_ENTRY(25b-linux_gateway_page, 31b-linux_gateway_page)
1118 ASM_EXCEPTIONTABLE_ENTRY(26b-linux_gateway_page, 31b-linux_gateway_page)
1119 ASM_EXCEPTIONTABLE_ENTRY(27b-linux_gateway_page, 31b-linux_gateway_page)
1120 ASM_EXCEPTIONTABLE_ENTRY(28b-linux_gateway_page, 31b-linux_gateway_page)
1121 ASM_EXCEPTIONTABLE_ENTRY(29b-linux_gateway_page, 31b-linux_gateway_page)
1122
1123 /***************************************************
1124 LWS atomic store.
1125
1126 %r26 - Address to store
1127 %r25 - Size of the variable (0/1/2/3 for 8/16/32/64 bit)
1128 %r24 - Address of value to store
1129 %r28 - Return non-zero on failure
1130 %r21 - Kernel error code
1131
1132 %r21 returns the following error codes:
1133 EAGAIN - CAS is busy, ldcw failed, try again.
1134 EFAULT - Read or write failed.
1135
1136 If EAGAIN is returned, %r28 indicates the busy reason:
1137 r28 == 1 - CAS is busy. lock contended.
1138 r28 == 2 - CAS is busy. ldcw failed.
1139 r28 == 3 - CAS is busy. page fault.
1140
1141 Scratch: r20, r1
1142
1143 ****************************************************/
1144
1145lws_atomic_store:
1146#ifdef CONFIG_64BIT
1147 /* Wide mode user process? */
1148 bb,<,n %sp, 31, atomic_store_begin
1149
1150 /* Clip the input registers for 32-bit processes. We don't
1151 need to clip %r23 as we only use it for word operations */
1152 depdi 0, 31, 32, %r26
1153 depdi 0, 31, 32, %r25
1154 depdi 0, 31, 32, %r24
1155#endif
1156
1157atomic_store_begin:
1158 /* Check the validity of the size pointer */
1159 subi,>>= 3, %r25, %r0
1160 b,n lws_exit_nosys
1161
1162 shlw %r25, 1, %r1
1163 blr %r1, %r0
1164 nop
1165
1166 /* Perform exception checks */
1167
1168 /* 8-bit store */
11691: ldb 0(%r24), %r20
1170 b,n atomic_store_start
1171 nop
1172 nop
1173
1174 /* 16-bit store */
11752: ldh 0(%r24), %r20
1176 b,n atomic_store_start
1177 nop
1178 nop
1179
1180 /* 32-bit store */
11813: ldw 0(%r24), %r20
1182 b,n atomic_store_start
1183 nop
1184 nop
1185
1186 /* 64-bit store */
1187#ifdef CONFIG_64BIT
11884: ldd 0(%r24), %r20
1189#else
11904: ldw 0(%r24), %r20
11915: ldw 4(%r24), %r20
1192#endif
1193
1194atomic_store_start:
1195 /* Trigger memory reference interruptions without writing to memory */
1196 copy %r26, %r28
1197 depi_safe 0, 31, 2, %r28
11986: ldw 0(%r28), %r1
11997: stbys,e %r0, 0(%r28)
1200
1201 /* Calculate 8-bit hash index from virtual address */
1202 extru_safe %r26, 27, 8, %r20
1203
1204 /* Load start of lock table */
1205 ldil L%lws_lock_start, %r28
1206 ldo R%lws_lock_start(%r28), %r28
1207
1208 /* Find lock to use, the hash index is one of 0 to
1209 255, multiplied by 16 (keep it 16-byte aligned)
1210 and add to the lock table offset. */
1211 shlw %r20, 4, %r20
1212 add %r20, %r28, %r20
1213
1214 rsm PSW_SM_I, %r0 /* Disable interrupts */
1215
1216 /* Try to acquire the lock */
1217 LDCW 0(%sr2,%r20), %r28
1218 spinlock_check %r28, %r21
1219 comclr,<> %r0, %r28, %r0
1220 b,n lws_wouldblock
1221
1222 /* Disable page faults to prevent sleeping in critical region */
1223 lws_pagefault_disable %r21,%r28
1224
1225 /* NOTES:
1226 This all works because intr_do_signal
1227 and schedule both check the return iasq
1228 and see that we are on the kernel page
1229 so this process is never scheduled off
1230 or is ever sent any signal of any sort,
1231 thus it is wholly atomic from userspace's
1232 perspective
1233 */
1234
1235 /* Jump to the correct function */
1236 blr %r1, %r0
1237 /* Set %r28 as non-zero for now */
1238 ldo 1(%r0),%r28
1239
1240 /* 8-bit store */
12419: ldb 0(%r24), %r1
124210: stb %r1, 0(%r26)
1243 b lws_exit_noerror
1244 copy %r0, %r28
1245
1246 /* 16-bit store */
124711: ldh 0(%r24), %r1
124812: sth %r1, 0(%r26)
1249 b lws_exit_noerror
1250 copy %r0, %r28
1251
1252 /* 32-bit store */
125313: ldw 0(%r24), %r1
125414: stw %r1, 0(%r26)
1255 b lws_exit_noerror
1256 copy %r0, %r28
1257
1258 /* 64-bit store */
1259#ifdef CONFIG_64BIT
126015: ldd 0(%r24), %r1
126116: std %r1, 0(%r26)
1262#else
126315: flddx 0(%r24), %fr4
126416: fstdx %fr4, 0(%r26)
1265#endif
1266 b lws_exit_noerror
1267 copy %r0, %r28
1268
1269 /* A fault occurred on load or stbys,e store */
127030: b,n lws_fault
1271 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page)
1272 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page)
1273 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page)
1274 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page)
1275#ifndef CONFIG_64BIT
1276 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page)
1277#endif
1278
1279 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page)
1280 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page)
1281
1282 /* A page fault occurred in critical region */
128331: b,n lws_pagefault
1284 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 31b-linux_gateway_page)
1285 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 31b-linux_gateway_page)
1286 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 31b-linux_gateway_page)
1287 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 31b-linux_gateway_page)
1288 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 31b-linux_gateway_page)
1289 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page)
1290 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page)
1291 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page)
1292
1293 /* Make sure nothing else is placed on this page */
1294 .align PAGE_SIZE
1295END(linux_gateway_page)
1296ENTRY(end_linux_gateway_page)
1297
1298 /* Relocate symbols assuming linux_gateway_page is mapped
1299 to virtual address 0x0 */
1300
1301#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page)
1302
1303 .section .rodata,"a"
1304
1305 .align 8
1306 /* Light-weight-syscall table */
1307 /* Start of lws table. */
1308ENTRY(lws_table)
1309 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic 32bit CAS */
1310 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic 32bit CAS */
1311 LWS_ENTRY(compare_and_swap_2) /* 2 - Atomic 64bit CAS */
1312 LWS_ENTRY(atomic_xchg) /* 3 - Atomic Exchange */
1313 LWS_ENTRY(atomic_store) /* 4 - Atomic Store */
1314END(lws_table)
1315 /* End of lws table */
1316
1317#ifdef CONFIG_64BIT
1318#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat)
1319#else
1320#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
1321#endif
1322#define __SYSCALL(nr, entry) ASM_ULONG_INSN entry
1323 .align 8
1324ENTRY(sys_call_table)
1325 .export sys_call_table,data
1326#include <asm/syscall_table_32.h> /* 32-bit syscalls */
1327END(sys_call_table)
1328
1329#ifdef CONFIG_64BIT
1330#undef __SYSCALL_WITH_COMPAT
1331#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
1332 .align 8
1333ENTRY(sys_call_table64)
1334#include <asm/syscall_table_64.h> /* 64-bit syscalls */
1335END(sys_call_table64)
1336#endif
1337
1338 /*
1339 All light-weight-syscall atomic operations
1340 will use this set of locks
1341
1342 NOTE: The lws_lock_start symbol must be
1343 at least 16-byte aligned for safe use
1344 with ldcw.
1345 */
1346 .section .data
1347 .align L1_CACHE_BYTES
1348ENTRY(lws_lock_start)
1349 /* lws locks */
1350 .rept 256
1351 /* Keep locks aligned at 16-bytes */
1352 .word __ARCH_SPIN_LOCK_UNLOCKED_VAL
1353 .word 0
1354 .word 0
1355 .word 0
1356 .endr
1357END(lws_lock_start)
1358 .previous
1359
1360.end