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parisc: split syscall_trace into two halves
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CommitLineData
1da177e4
LT
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
0013a854 10#include <asm/asm-offsets.h>
1da177e4
LT
11#include <asm/unistd.h>
12#include <asm/errno.h>
1c593571 13#include <asm/page.h>
1da177e4
LT
14#include <asm/psw.h>
15#include <asm/thread_info.h>
1da177e4
LT
16#include <asm/assembly.h>
17#include <asm/processor.h>
18
8e9e9844
HD
19#include <linux/linkage.h>
20
1da177e4
LT
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
0b3d643f 27 .level LEVEL
8e9e9844 28
dfcf753b 29 .text
1da177e4
LT
30
31 .import syscall_exit,code
32 .import syscall_exit_rfi,code
1da177e4
LT
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
1c593571 42 .align PAGE_SIZE
8e9e9844 43ENTRY(linux_gateway_page)
1da177e4
LT
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 0xb4, lws uses 1 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 /* Unconditional branch to lws_start, located on the
57 same gateway page */
58 b,n lws_start
59
60 /* Fill from 0xb4 to 0xe0 */
61 .rept 11
62 KILL_INSN
63 .endr
64
65 /* This function MUST be located at 0xe0 for glibc's threading
66 mechanism to work. DO NOT MOVE THIS CODE EVER! */
67set_thread_pointer:
68 gate .+8, %r0 /* increase privilege */
69 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
70 be 0(%sr7,%r31) /* return to user space */
71 mtctl %r26, %cr27 /* move arg0 to the control register */
72
73 /* Increase the chance of trapping if random jumps occur to this
74 address, fill from 0xf0 to 0x100 */
75 .rept 4
76 KILL_INSN
77 .endr
78
79/* This address must remain fixed at 0x100 for glibc's syscalls to work */
80 .align 256
81linux_gateway_entry:
82 gate .+8, %r0 /* become privileged */
83 mtsp %r0,%sr4 /* get kernel space into sr4 */
84 mtsp %r0,%sr5 /* get kernel space into sr5 */
85 mtsp %r0,%sr6 /* get kernel space into sr6 */
86 mfsp %sr7,%r1 /* save user sr7 */
87 mtsp %r1,%sr3 /* and store it in sr3 */
88
413059f2 89#ifdef CONFIG_64BIT
1da177e4
LT
90 /* for now we can *always* set the W bit on entry to the syscall
91 * since we don't support wide userland processes. We could
92 * also save the current SM other than in r0 and restore it on
93 * exit from the syscall, and also use that value to know
94 * whether to do narrow or wide syscalls. -PB
95 */
96 ssm PSW_SM_W, %r1
97 extrd,u %r1,PSW_W_BIT,1,%r1
98 /* sp must be aligned on 4, so deposit the W bit setting into
99 * the bottom of sp temporarily */
100 or,ev %r1,%r30,%r30
101 b,n 1f
102 /* The top halves of argument registers must be cleared on syscall
103 * entry from narrow executable.
104 */
105 depdi 0, 31, 32, %r26
106 depdi 0, 31, 32, %r25
107 depdi 0, 31, 32, %r24
108 depdi 0, 31, 32, %r23
109 depdi 0, 31, 32, %r22
110 depdi 0, 31, 32, %r21
1111:
112#endif
113 mfctl %cr30,%r1
114 xor %r1,%r30,%r30 /* ye olde xor trick */
115 xor %r1,%r30,%r1
116 xor %r1,%r30,%r30
117
118 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */
119
120 /* N.B.: It is critical that we don't set sr7 to 0 until r30
121 * contains a valid kernel stack pointer. It is also
122 * critical that we don't start using the kernel stack
123 * until after sr7 has been set to 0.
124 */
125
126 mtsp %r0,%sr7 /* get kernel space into sr7 */
127 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */
128 mfctl %cr30,%r1 /* get task ptr in %r1 */
129 LDREG TI_TASK(%r1),%r1
130
131 /* Save some registers for sigcontext and potential task
132 switch (see entry.S for the details of which ones are
133 saved/restored). TASK_PT_PSW is zeroed so we can see whether
134 a process is on a syscall or not. For an interrupt the real
135 PSW value is stored. This is needed for gdb and sys_ptrace. */
136 STREG %r0, TASK_PT_PSW(%r1)
137 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */
138 STREG %r19, TASK_PT_GR19(%r1)
139
140 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */
413059f2 141#ifdef CONFIG_64BIT
1da177e4
LT
142 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */
143#if 0
144 xor %r19,%r2,%r2 /* clear bottom bit */
145 depd,z %r19,1,1,%r19
146 std %r19,TASK_PT_PSW(%r1)
147#endif
148#endif
149 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */
150
aa0eecb0 151 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */
1da177e4
LT
152 STREG %r21, TASK_PT_GR21(%r1)
153 STREG %r22, TASK_PT_GR22(%r1)
154 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */
155 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */
156 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */
157 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */
158 STREG %r27, TASK_PT_GR27(%r1) /* user dp */
159 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */
160 STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */
161 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */
162 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */
163
164 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */
165 save_fp %r27 /* or potential task switch */
166
167 mfctl %cr11, %r27 /* i.e. SAR */
168 STREG %r27, TASK_PT_SAR(%r1)
169
170 loadgp
171
413059f2 172#ifdef CONFIG_64BIT
1da177e4
LT
173 ldo -16(%r30),%r29 /* Reference param save area */
174 copy %r19,%r2 /* W bit back to r2 */
175#else
176 /* no need to save these on stack in wide mode because the first 8
177 * args are passed in registers */
178 stw %r22, -52(%r30) /* 5th argument */
179 stw %r21, -56(%r30) /* 6th argument */
180#endif
181
182 /* Are we being ptraced? */
183 mfctl %cr30, %r1
184 LDREG TI_TASK(%r1),%r1
376e210b 185 ldw TASK_PTRACE(%r1), %r1
1da177e4
LT
186 bb,<,n %r1,31,.Ltracesys
187
188 /* Note! We cannot use the syscall table that is mapped
189 nearby since the gateway page is mapped execute-only. */
190
413059f2 191#ifdef CONFIG_64BIT
1da177e4
LT
192 ldil L%sys_call_table, %r1
193 or,= %r2,%r2,%r2
194 addil L%(sys_call_table64-sys_call_table), %r1
195 ldo R%sys_call_table(%r1), %r19
196 or,= %r2,%r2,%r2
197 ldo R%sys_call_table64(%r1), %r19
198#else
199 ldil L%sys_call_table, %r1
200 ldo R%sys_call_table(%r1), %r19
201#endif
3bb457af 202 comiclr,>> __NR_Linux_syscalls, %r20, %r0
1da177e4
LT
203 b,n .Lsyscall_nosys
204
205 LDREGX %r20(%r19), %r19
206
207 /* If this is a sys_rt_sigreturn call, and the signal was received
208 * when not in_syscall, then we want to return via syscall_exit_rfi,
209 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
210 * trampoline code in signal.c).
211 */
212 ldi __NR_rt_sigreturn,%r2
213 comb,= %r2,%r20,.Lrt_sigreturn
214.Lin_syscall:
215 ldil L%syscall_exit,%r2
216 be 0(%sr7,%r19)
217 ldo R%syscall_exit(%r2),%r2
218.Lrt_sigreturn:
219 comib,<> 0,%r25,.Lin_syscall
220 ldil L%syscall_exit_rfi,%r2
221 be 0(%sr7,%r19)
222 ldo R%syscall_exit_rfi(%r2),%r2
223
224 /* Note! Because we are not running where we were linked, any
225 calls to functions external to this file must be indirect. To
226 be safe, we apply the opposite rule to functions within this
227 file, with local labels given to them to ensure correctness. */
228
229.Lsyscall_nosys:
230syscall_nosys:
231 ldil L%syscall_exit,%r1
232 be R%syscall_exit(%sr7,%r1)
233 ldo -ENOSYS(%r0),%r28 /* set errno */
234
235
236/* Warning! This trace code is a virtual duplicate of the code above so be
237 * sure to maintain both! */
238.Ltracesys:
239tracesys:
240 /* Need to save more registers so the debugger can see where we
241 * are. This saves only the lower 8 bits of PSW, so that the C
242 * bit is still clear on syscalls, and the D bit is set if this
243 * full register save path has been executed. We check the D
244 * bit on syscall_return_rfi to determine which registers to
245 * restore. An interrupt results in a full PSW saved with the
246 * C bit set, a non-straced syscall entry results in C and D clear
247 * in the saved PSW.
248 */
249 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
250 LDREG TI_TASK(%r1), %r1
251 ssm 0,%r2
252 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */
253 mfsp %sr0,%r2
254 STREG %r2,TASK_PT_SR0(%r1)
255 mfsp %sr1,%r2
256 STREG %r2,TASK_PT_SR1(%r1)
257 mfsp %sr2,%r2
258 STREG %r2,TASK_PT_SR2(%r1)
259 mfsp %sr3,%r2
260 STREG %r2,TASK_PT_SR3(%r1)
261 STREG %r2,TASK_PT_SR4(%r1)
262 STREG %r2,TASK_PT_SR5(%r1)
263 STREG %r2,TASK_PT_SR6(%r1)
264 STREG %r2,TASK_PT_SR7(%r1)
265 STREG %r2,TASK_PT_IASQ0(%r1)
266 STREG %r2,TASK_PT_IASQ1(%r1)
267 LDREG TASK_PT_GR31(%r1),%r2
268 STREG %r2,TASK_PT_IAOQ0(%r1)
269 ldo 4(%r2),%r2
270 STREG %r2,TASK_PT_IAOQ1(%r1)
271 ldo TASK_REGS(%r1),%r2
272 /* reg_save %r2 */
273 STREG %r3,PT_GR3(%r2)
274 STREG %r4,PT_GR4(%r2)
275 STREG %r5,PT_GR5(%r2)
276 STREG %r6,PT_GR6(%r2)
277 STREG %r7,PT_GR7(%r2)
278 STREG %r8,PT_GR8(%r2)
279 STREG %r9,PT_GR9(%r2)
280 STREG %r10,PT_GR10(%r2)
281 STREG %r11,PT_GR11(%r2)
282 STREG %r12,PT_GR12(%r2)
283 STREG %r13,PT_GR13(%r2)
284 STREG %r14,PT_GR14(%r2)
285 STREG %r15,PT_GR15(%r2)
286 STREG %r16,PT_GR16(%r2)
287 STREG %r17,PT_GR17(%r2)
288 STREG %r18,PT_GR18(%r2)
289 /* Finished saving things for the debugger */
290
2798af1a
KM
291 copy %r2,%r26
292 ldil L%do_syscall_trace_enter,%r1
1da177e4 293 ldil L%tracesys_next,%r2
2798af1a 294 be R%do_syscall_trace_enter(%sr7,%r1)
1da177e4
LT
295 ldo R%tracesys_next(%r2),%r2
296
2798af1a
KM
297tracesys_next:
298 /* do_syscall_trace_enter either returned the syscallno, or -1L,
299 * so we skip restoring the PT_GR20 below, since we pulled it from
300 * task->thread.regs.gr[20] above.
301 */
302 copy %ret0,%r20
1da177e4
LT
303 ldil L%sys_call_table,%r1
304 ldo R%sys_call_table(%r1), %r19
305
306 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
307 LDREG TI_TASK(%r1), %r1
1da177e4
LT
308 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */
309 LDREG TASK_PT_GR25(%r1), %r25
310 LDREG TASK_PT_GR24(%r1), %r24
311 LDREG TASK_PT_GR23(%r1), %r23
413059f2 312#ifdef CONFIG_64BIT
1da177e4
LT
313 LDREG TASK_PT_GR22(%r1), %r22
314 LDREG TASK_PT_GR21(%r1), %r21
315 ldo -16(%r30),%r29 /* Reference param save area */
316#endif
317
318 comiclr,>>= __NR_Linux_syscalls, %r20, %r0
319 b,n .Lsyscall_nosys
320
321 LDREGX %r20(%r19), %r19
322
323 /* If this is a sys_rt_sigreturn call, and the signal was received
324 * when not in_syscall, then we want to return via syscall_exit_rfi,
325 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
326 * trampoline code in signal.c).
327 */
328 ldi __NR_rt_sigreturn,%r2
329 comb,= %r2,%r20,.Ltrace_rt_sigreturn
330.Ltrace_in_syscall:
331 ldil L%tracesys_exit,%r2
332 be 0(%sr7,%r19)
333 ldo R%tracesys_exit(%r2),%r2
334
335 /* Do *not* call this function on the gateway page, because it
336 makes a direct call to syscall_trace. */
337
338tracesys_exit:
339 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
340 LDREG TI_TASK(%r1), %r1
413059f2 341#ifdef CONFIG_64BIT
1da177e4
LT
342 ldo -16(%r30),%r29 /* Reference param save area */
343#endif
2798af1a
KM
344 ldo TASK_REGS(%r1),%r26
345 bl do_syscall_trace_exit,%r2
1da177e4
LT
346 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */
347 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
348 LDREG TI_TASK(%r1), %r1
349 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */
350
351 ldil L%syscall_exit,%r1
352 be,n R%syscall_exit(%sr7,%r1)
353
354.Ltrace_rt_sigreturn:
355 comib,<> 0,%r25,.Ltrace_in_syscall
356 ldil L%tracesys_sigexit,%r2
357 be 0(%sr7,%r19)
358 ldo R%tracesys_sigexit(%r2),%r2
359
360tracesys_sigexit:
361 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
5837d42f 362 LDREG TI_TASK(%r1), %r1
413059f2 363#ifdef CONFIG_64BIT
1da177e4
LT
364 ldo -16(%r30),%r29 /* Reference param save area */
365#endif
2798af1a
KM
366 bl do_syscall_trace_exit,%r2
367 ldo TASK_REGS(%r1),%r26
1da177e4
LT
368
369 ldil L%syscall_exit_rfi,%r1
370 be,n R%syscall_exit_rfi(%sr7,%r1)
371
372
373 /*********************************************************
c84c3a69 374 32/64-bit Light-Weight-Syscall ABI
1da177e4 375
c84c3a69
HD
376 * - Indicates a hint for userspace inline asm
377 implementations.
1da177e4 378
c84c3a69
HD
379 Syscall number (caller-saves)
380 - %r20
381 * In asm clobber.
1da177e4 382
c84c3a69
HD
383 Argument registers (caller-saves)
384 - %r26, %r25, %r24, %r23, %r22
385 * In asm input.
386
387 Return registers (caller-saves)
388 - %r28 (return), %r21 (errno)
389 * In asm output.
390
391 Caller-saves registers
392 - %r1, %r27, %r29
393 - %r2 (return pointer)
394 - %r31 (ble link register)
395 * In asm clobber.
396
397 Callee-saves registers
398 - %r3-%r18
399 - %r30 (stack pointer)
400 * Not in asm clobber.
401
402 If userspace is 32-bit:
403 Callee-saves registers
404 - %r19 (32-bit PIC register)
405
406 Differences from 32-bit calling convention:
407 - Syscall number in %r20
408 - Additional argument register %r22 (arg4)
409 - Callee-saves %r19.
410
411 If userspace is 64-bit:
412 Callee-saves registers
413 - %r27 (64-bit PIC register)
414
415 Differences from 64-bit calling convention:
416 - Syscall number in %r20
417 - Additional argument register %r22 (arg4)
418 - Callee-saves %r27.
1da177e4
LT
419
420 Error codes returned by entry path:
421
422 ENOSYS - r20 was an invalid LWS number.
423
424 *********************************************************/
425lws_start:
426 /* Gate and ensure we return to userspace */
427 gate .+8, %r0
428 depi 3, 31, 2, %r31 /* Ensure we return to userspace */
429
413059f2 430#ifdef CONFIG_64BIT
1da177e4
LT
431 /* FIXME: If we are a 64-bit kernel just
432 * turn this on unconditionally.
433 */
434 ssm PSW_SM_W, %r1
435 extrd,u %r1,PSW_W_BIT,1,%r1
436 /* sp must be aligned on 4, so deposit the W bit setting into
437 * the bottom of sp temporarily */
438 or,ev %r1,%r30,%r30
439
440 /* Clip LWS number to a 32-bit value always */
441 depdi 0, 31, 32, %r20
442#endif
443
444 /* Is the lws entry number valid? */
445 comiclr,>>= __NR_lws_entries, %r20, %r0
446 b,n lws_exit_nosys
447
448 /* WARNING: Trashing sr2 and sr3 */
449 mfsp %sr7,%r1 /* get userspace into sr3 */
450 mtsp %r1,%sr3
451 mtsp %r0,%sr2 /* get kernel space into sr2 */
452
453 /* Load table start */
454 ldil L%lws_table, %r1
455 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
456 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */
457
458 /* Jump to lws, lws table pointers already relocated */
459 be,n 0(%sr2,%r21)
460
461lws_exit_nosys:
462 ldo -ENOSYS(%r0),%r21 /* set errno */
463 /* Fall through: Return to userspace */
464
465lws_exit:
413059f2 466#ifdef CONFIG_64BIT
1da177e4
LT
467 /* decide whether to reset the wide mode bit
468 *
469 * For a syscall, the W bit is stored in the lowest bit
470 * of sp. Extract it and reset W if it is zero */
471 extrd,u,*<> %r30,63,1,%r1
472 rsm PSW_SM_W, %r0
473 /* now reset the lowest bit of sp if it was set */
474 xor %r30,%r1,%r30
475#endif
476 be,n 0(%sr3, %r31)
477
478
479
480 /***************************************************
481 Implementing CAS as an atomic operation:
482
483 %r26 - Address to examine
484 %r25 - Old value to check (old)
485 %r24 - New value to set (new)
486 %r28 - Return prev through this register.
487 %r21 - Kernel error code
488
489 If debugging is DISabled:
490
491 %r21 has the following meanings:
492
493 EAGAIN - CAS is busy, ldcw failed, try again.
494 EFAULT - Read or write failed.
495
496 If debugging is enabled:
497
498 EDEADLOCK - CAS called recursively.
499 EAGAIN && r28 == 1 - CAS is busy. Lock contended.
500 EAGAIN && r28 == 2 - CAS is busy. ldcw failed.
501 EFAULT - Read or write failed.
502
503 Scratch: r20, r28, r1
504
505 ****************************************************/
506
507 /* Do not enable LWS debugging */
508#define ENABLE_LWS_DEBUG 0
509
510 /* ELF64 Process entry path */
511lws_compare_and_swap64:
413059f2 512#ifdef CONFIG_64BIT
1da177e4
LT
513 b,n lws_compare_and_swap
514#else
515 /* If we are not a 64-bit kernel, then we don't
c84c3a69
HD
516 * have 64-bit input registers, and calling
517 * the 64-bit LWS CAS returns ENOSYS.
1da177e4
LT
518 */
519 b,n lws_exit_nosys
520#endif
521
522 /* ELF32 Process entry path */
523lws_compare_and_swap32:
413059f2 524#ifdef CONFIG_64BIT
1da177e4
LT
525 /* Clip all the input registers */
526 depdi 0, 31, 32, %r26
527 depdi 0, 31, 32, %r25
528 depdi 0, 31, 32, %r24
529#endif
530
531lws_compare_and_swap:
532#ifdef CONFIG_SMP
533 /* Load start of lock table */
534 ldil L%lws_lock_start, %r20
535 ldo R%lws_lock_start(%r20), %r28
536
537 /* Extract four bits from r26 and hash lock (Bits 4-7) */
538 extru %r26, 27, 4, %r20
539
540 /* Find lock to use, the hash is either one of 0 to
541 15, multiplied by 16 (keep it 16-byte aligned)
542 and add to the lock table offset. */
543 shlw %r20, 4, %r20
544 add %r20, %r28, %r20
545
b5e8b733 546# if ENABLE_LWS_DEBUG
1da177e4
LT
547 /*
548 DEBUG, check for deadlock!
549 If the thread register values are the same
550 then we were the one that locked it last and
551 this is a recurisve call that will deadlock.
552 We *must* giveup this call and fail.
553 */
554 ldw 4(%sr2,%r20), %r28 /* Load thread register */
aa0eecb0 555 /* WARNING: If cr27 cycles to the same value we have problems */
1da177e4
LT
556 mfctl %cr27, %r21 /* Get current thread register */
557 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */
558 b lws_exit /* Return error! */
559 ldo -EDEADLOCK(%r0), %r21
560cas_lock:
561 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */
562 ldo 1(%r0), %r28 /* 1st case */
563 b lws_exit /* Contended... */
564 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
565cas_nocontend:
566# endif
567/* ENABLE_LWS_DEBUG */
568
64f49532 569 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
1da177e4
LT
570 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */
571cas_wouldblock:
572 ldo 2(%r0), %r28 /* 2nd case */
573 b lws_exit /* Contended... */
574 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
575#endif
576/* CONFIG_SMP */
577
578 /*
579 prev = *addr;
580 if ( prev == old )
581 *addr = new;
582 return prev;
583 */
584
585 /* NOTES:
586 This all works becuse intr_do_signal
587 and schedule both check the return iasq
588 and see that we are on the kernel page
589 so this process is never scheduled off
590 or is ever sent any signal of any sort,
591 thus it is wholly atomic from usrspaces
592 perspective
593 */
594cas_action:
b5e8b733 595#if defined CONFIG_SMP && ENABLE_LWS_DEBUG
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LT
596 /* DEBUG */
597 mfctl %cr27, %r1
598 stw %r1, 4(%sr2,%r20)
599#endif
600 /* The load and store could fail */
6011: ldw 0(%sr3,%r26), %r28
602 sub,<> %r28, %r25, %r0
6032: stw %r24, 0(%sr3,%r26)
604#ifdef CONFIG_SMP
605 /* Free lock */
606 stw %r20, 0(%sr2,%r20)
b5e8b733 607# if ENABLE_LWS_DEBUG
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LT
608 /* Clear thread register indicator */
609 stw %r0, 4(%sr2,%r20)
610# endif
611#endif
612 /* Return to userspace, set no error */
613 b lws_exit
614 copy %r0, %r21
615
6163:
617 /* Error occured on load or store */
618#ifdef CONFIG_SMP
619 /* Free lock */
620 stw %r20, 0(%sr2,%r20)
b5e8b733 621# if ENABLE_LWS_DEBUG
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LT
622 stw %r0, 4(%sr2,%r20)
623# endif
624#endif
625 b lws_exit
626 ldo -EFAULT(%r0),%r21 /* set errno */
627 nop
628 nop
629 nop
630 nop
631
632 /* Two exception table entries, one for the load,
633 the other for the store. Either return -EFAULT.
634 Each of the entries must be relocated. */
635 .section __ex_table,"aw"
0b3d643f
HD
636 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page)
637 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page)
1da177e4
LT
638 .previous
639
1da177e4
LT
640
641 /* Make sure nothing else is placed on this page */
1c593571 642 .align PAGE_SIZE
8e9e9844
HD
643END(linux_gateway_page)
644ENTRY(end_linux_gateway_page)
1da177e4
LT
645
646 /* Relocate symbols assuming linux_gateway_page is mapped
647 to virtual address 0x0 */
8e9e9844 648
0b3d643f 649#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page)
1da177e4 650
1bcdd854
HD
651 .section .rodata,"a"
652
1c593571 653 .align PAGE_SIZE
1da177e4
LT
654 /* Light-weight-syscall table */
655 /* Start of lws table. */
8e9e9844 656ENTRY(lws_table)
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LT
657 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */
658 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */
8e9e9844 659END(lws_table)
1da177e4
LT
660 /* End of lws table */
661
1c593571 662 .align PAGE_SIZE
8e9e9844 663ENTRY(sys_call_table)
1da177e4 664#include "syscall_table.S"
8e9e9844 665END(sys_call_table)
1da177e4 666
413059f2 667#ifdef CONFIG_64BIT
1c593571 668 .align PAGE_SIZE
8e9e9844 669ENTRY(sys_call_table64)
1da177e4
LT
670#define SYSCALL_TABLE_64BIT
671#include "syscall_table.S"
8e9e9844 672END(sys_call_table64)
1da177e4
LT
673#endif
674
675#ifdef CONFIG_SMP
676 /*
677 All light-weight-syscall atomic operations
678 will use this set of locks
c84c3a69
HD
679
680 NOTE: The lws_lock_start symbol must be
681 at least 16-byte aligned for safe use
682 with ldcw.
1da177e4 683 */
dfcf753b 684 .section .data
873d50e2 685 .align PAGE_SIZE
8e9e9844 686ENTRY(lws_lock_start)
1da177e4 687 /* lws locks */
1da177e4
LT
688 .rept 16
689 /* Keep locks aligned at 16-bytes */
690 .word 1
691 .word 0
692 .word 0
693 .word 0
694 .endr
8e9e9844 695END(lws_lock_start)
1da177e4
LT
696 .previous
697#endif
698/* CONFIG_SMP for lws_lock_start */
699
700.end
701
702