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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
43#include <linux/linkage.h>
44
45 /* We fill the empty parts of the gateway page with
46 * something that will kill the kernel or a
47 * userspace application.
48 */
49#define KILL_INSN break 0,0
50
51 .level PA_ASM_LEVEL
52
53 .text
54
55 .import syscall_exit,code
56 .import syscall_exit_rfi,code
57
58 /* Linux gateway page is aliased to virtual page 0 in the kernel
59 * address space. Since it is a gateway page it cannot be
60 * dereferenced, so null pointers will still fault. We start
61 * the actual entry point at 0x100. We put break instructions
62 * at the beginning of the page to trap null indirect function
63 * pointers.
64 */
65
66 .align PAGE_SIZE
67ENTRY(linux_gateway_page)
68
69 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */
70 .rept 44
71 KILL_INSN
72 .endr
73
74 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */
75 /* Light-weight-syscall entry must always be located at 0xb0 */
76 /* WARNING: Keep this number updated with table size changes */
77#define __NR_lws_entries (3)
78
79lws_entry:
80 gate lws_start, %r0 /* increase privilege */
81 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
82
83 /* Fill from 0xb8 to 0xe0 */
84 .rept 10
85 KILL_INSN
86 .endr
87
88 /* This function MUST be located at 0xe0 for glibc's threading
89 mechanism to work. DO NOT MOVE THIS CODE EVER! */
90set_thread_pointer:
91 gate .+8, %r0 /* increase privilege */
92 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
93 be 0(%sr7,%r31) /* return to user space */
94 mtctl %r26, %cr27 /* move arg0 to the control register */
95
96 /* Increase the chance of trapping if random jumps occur to this
97 address, fill from 0xf0 to 0x100 */
98 .rept 4
99 KILL_INSN
100 .endr
101
102/* This address must remain fixed at 0x100 for glibc's syscalls to work */
103 .align LINUX_GATEWAY_ADDR
104linux_gateway_entry:
105 gate .+8, %r0 /* become privileged */
106 mtsp %r0,%sr4 /* get kernel space into sr4 */
107 mtsp %r0,%sr5 /* get kernel space into sr5 */
108 mtsp %r0,%sr6 /* get kernel space into sr6 */
109
110#ifdef CONFIG_64BIT
111 /* Store W bit on entry to the syscall in case it's a wide userland
112 * process. */
113 ssm PSW_SM_W, %r1
114 extrd,u %r1,PSW_W_BIT,1,%r1
115 /* sp must be aligned on 4, so deposit the W bit setting into
116 * the bottom of sp temporarily */
117 or,ev %r1,%r30,%r30
118 b,n 1f
119 /* The top halves of argument registers must be cleared on syscall
120 * entry from narrow executable.
121 */
122 depdi 0, 31, 32, %r26
123 depdi 0, 31, 32, %r25
124 depdi 0, 31, 32, %r24
125 depdi 0, 31, 32, %r23
126 depdi 0, 31, 32, %r22
127 depdi 0, 31, 32, %r21
1281:
129#endif
130
131 /* We use a rsm/ssm pair to prevent sr3 from being clobbered
132 * by external interrupts.
133 */
134 mfsp %sr7,%r1 /* save user sr7 */
135 rsm PSW_SM_I, %r0 /* disable interrupts */
136 mtsp %r1,%sr3 /* and store it in sr3 */
137
138 mfctl %cr30,%r1
139 xor %r1,%r30,%r30 /* ye olde xor trick */
140 xor %r1,%r30,%r1
141 xor %r1,%r30,%r30
142
143 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */
144
145 /* N.B.: It is critical that we don't set sr7 to 0 until r30
146 * contains a valid kernel stack pointer. It is also
147 * critical that we don't start using the kernel stack
148 * until after sr7 has been set to 0.
149 */
150
151 mtsp %r0,%sr7 /* get kernel space into sr7 */
152 ssm PSW_SM_I, %r0 /* enable interrupts */
153 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */
154 mfctl %cr30,%r1 /* get task ptr in %r1 */
155 LDREG TI_TASK(%r1),%r1
156
157 /* Save some registers for sigcontext and potential task
158 switch (see entry.S for the details of which ones are
159 saved/restored). TASK_PT_PSW is zeroed so we can see whether
160 a process is on a syscall or not. For an interrupt the real
161 PSW value is stored. This is needed for gdb and sys_ptrace. */
162 STREG %r0, TASK_PT_PSW(%r1)
163 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */
164 STREG %r19, TASK_PT_GR19(%r1)
165
166 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */
167#ifdef CONFIG_64BIT
168 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */
169#if 0
170 xor %r19,%r2,%r2 /* clear bottom bit */
171 depd,z %r19,1,1,%r19
172 std %r19,TASK_PT_PSW(%r1)
173#endif
174#endif
175 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */
176
177 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */
178 STREG %r21, TASK_PT_GR21(%r1)
179 STREG %r22, TASK_PT_GR22(%r1)
180 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */
181 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */
182 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */
183 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */
184 STREG %r27, TASK_PT_GR27(%r1) /* user dp */
185 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */
186 STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */
187 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */
188 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */
189
190 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */
191 save_fp %r27 /* or potential task switch */
192
193 mfctl %cr11, %r27 /* i.e. SAR */
194 STREG %r27, TASK_PT_SAR(%r1)
195
196 loadgp
197
198#ifdef CONFIG_64BIT
199 ldo -16(%r30),%r29 /* Reference param save area */
200 copy %r19,%r2 /* W bit back to r2 */
201#else
202 /* no need to save these on stack in wide mode because the first 8
203 * args are passed in registers */
204 stw %r22, -52(%r30) /* 5th argument */
205 stw %r21, -56(%r30) /* 6th argument */
206#endif
207
208 /* Are we being ptraced? */
209 mfctl %cr30, %r1
210 LDREG TI_FLAGS(%r1),%r1
211 ldi _TIF_SYSCALL_TRACE_MASK, %r19
212 and,COND(=) %r1, %r19, %r0
213 b,n .Ltracesys
214
215 /* Note! We cannot use the syscall table that is mapped
216 nearby since the gateway page is mapped execute-only. */
217
218#ifdef CONFIG_64BIT
219 ldil L%sys_call_table, %r1
220 or,= %r2,%r2,%r2
221 addil L%(sys_call_table64-sys_call_table), %r1
222 ldo R%sys_call_table(%r1), %r19
223 or,= %r2,%r2,%r2
224 ldo R%sys_call_table64(%r1), %r19
225#else
226 load32 sys_call_table, %r19
227#endif
228 comiclr,>> __NR_Linux_syscalls, %r20, %r0
229 b,n .Lsyscall_nosys
230
231 LDREGX %r20(%r19), %r19
232
233 /* If this is a sys_rt_sigreturn call, and the signal was received
234 * when not in_syscall, then we want to return via syscall_exit_rfi,
235 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
236 * trampoline code in signal.c).
237 */
238 ldi __NR_rt_sigreturn,%r2
239 comb,= %r2,%r20,.Lrt_sigreturn
240.Lin_syscall:
241 ldil L%syscall_exit,%r2
242 be 0(%sr7,%r19)
243 ldo R%syscall_exit(%r2),%r2
244.Lrt_sigreturn:
245 comib,<> 0,%r25,.Lin_syscall
246 ldil L%syscall_exit_rfi,%r2
247 be 0(%sr7,%r19)
248 ldo R%syscall_exit_rfi(%r2),%r2
249
250 /* Note! Because we are not running where we were linked, any
251 calls to functions external to this file must be indirect. To
252 be safe, we apply the opposite rule to functions within this
253 file, with local labels given to them to ensure correctness. */
254
255.Lsyscall_nosys:
256syscall_nosys:
257 ldil L%syscall_exit,%r1
258 be R%syscall_exit(%sr7,%r1)
259 ldo -ENOSYS(%r0),%r28 /* set errno */
260
261
262/* Warning! This trace code is a virtual duplicate of the code above so be
263 * sure to maintain both! */
264.Ltracesys:
265tracesys:
266 /* Need to save more registers so the debugger can see where we
267 * are. This saves only the lower 8 bits of PSW, so that the C
268 * bit is still clear on syscalls, and the D bit is set if this
269 * full register save path has been executed. We check the D
270 * bit on syscall_return_rfi to determine which registers to
271 * restore. An interrupt results in a full PSW saved with the
272 * C bit set, a non-straced syscall entry results in C and D clear
273 * in the saved PSW.
274 */
275 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
276 LDREG TI_TASK(%r1), %r1
277 ssm 0,%r2
278 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */
279 mfsp %sr0,%r2
280 STREG %r2,TASK_PT_SR0(%r1)
281 mfsp %sr1,%r2
282 STREG %r2,TASK_PT_SR1(%r1)
283 mfsp %sr2,%r2
284 STREG %r2,TASK_PT_SR2(%r1)
285 mfsp %sr3,%r2
286 STREG %r2,TASK_PT_SR3(%r1)
287 STREG %r2,TASK_PT_SR4(%r1)
288 STREG %r2,TASK_PT_SR5(%r1)
289 STREG %r2,TASK_PT_SR6(%r1)
290 STREG %r2,TASK_PT_SR7(%r1)
291 STREG %r2,TASK_PT_IASQ0(%r1)
292 STREG %r2,TASK_PT_IASQ1(%r1)
293 LDREG TASK_PT_GR31(%r1),%r2
294 STREG %r2,TASK_PT_IAOQ0(%r1)
295 ldo 4(%r2),%r2
296 STREG %r2,TASK_PT_IAOQ1(%r1)
297 ldo TASK_REGS(%r1),%r2
298 /* reg_save %r2 */
299 STREG %r3,PT_GR3(%r2)
300 STREG %r4,PT_GR4(%r2)
301 STREG %r5,PT_GR5(%r2)
302 STREG %r6,PT_GR6(%r2)
303 STREG %r7,PT_GR7(%r2)
304 STREG %r8,PT_GR8(%r2)
305 STREG %r9,PT_GR9(%r2)
306 STREG %r10,PT_GR10(%r2)
307 STREG %r11,PT_GR11(%r2)
308 STREG %r12,PT_GR12(%r2)
309 STREG %r13,PT_GR13(%r2)
310 STREG %r14,PT_GR14(%r2)
311 STREG %r15,PT_GR15(%r2)
312 STREG %r16,PT_GR16(%r2)
313 STREG %r17,PT_GR17(%r2)
314 STREG %r18,PT_GR18(%r2)
315 /* Finished saving things for the debugger */
316
317 copy %r2,%r26
318 ldil L%do_syscall_trace_enter,%r1
319 ldil L%tracesys_next,%r2
320 be R%do_syscall_trace_enter(%sr7,%r1)
321 ldo R%tracesys_next(%r2),%r2
322
323tracesys_next:
324 /* do_syscall_trace_enter either returned the syscallno, or -1L,
325 * so we skip restoring the PT_GR20 below, since we pulled it from
326 * task->thread.regs.gr[20] above.
327 */
328 copy %ret0,%r20
329
330 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
331 LDREG TI_TASK(%r1), %r1
332 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return value */
333 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */
334 LDREG TASK_PT_GR25(%r1), %r25
335 LDREG TASK_PT_GR24(%r1), %r24
336 LDREG TASK_PT_GR23(%r1), %r23
337 LDREG TASK_PT_GR22(%r1), %r22
338 LDREG TASK_PT_GR21(%r1), %r21
339#ifdef CONFIG_64BIT
340 ldo -16(%r30),%r29 /* Reference param save area */
341#else
342 stw %r22, -52(%r30) /* 5th argument */
343 stw %r21, -56(%r30) /* 6th argument */
344#endif
345
346 cmpib,COND(=),n -1,%r20,tracesys_exit /* seccomp may have returned -1 */
347 comiclr,>> __NR_Linux_syscalls, %r20, %r0
348 b,n .Ltracesys_nosys
349
350 /* Note! We cannot use the syscall table that is mapped
351 nearby since the gateway page is mapped execute-only. */
352
353#ifdef CONFIG_64BIT
354 LDREG TASK_PT_GR30(%r1), %r19 /* get users sp back */
355 extrd,u %r19,63,1,%r2 /* W hidden in bottom bit */
356
357 ldil L%sys_call_table, %r1
358 or,= %r2,%r2,%r2
359 addil L%(sys_call_table64-sys_call_table), %r1
360 ldo R%sys_call_table(%r1), %r19
361 or,= %r2,%r2,%r2
362 ldo R%sys_call_table64(%r1), %r19
363#else
364 load32 sys_call_table, %r19
365#endif
366
367 LDREGX %r20(%r19), %r19
368
369 /* If this is a sys_rt_sigreturn call, and the signal was received
370 * when not in_syscall, then we want to return via syscall_exit_rfi,
371 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
372 * trampoline code in signal.c).
373 */
374 ldi __NR_rt_sigreturn,%r2
375 comb,= %r2,%r20,.Ltrace_rt_sigreturn
376.Ltrace_in_syscall:
377 ldil L%tracesys_exit,%r2
378 be 0(%sr7,%r19)
379 ldo R%tracesys_exit(%r2),%r2
380
381.Ltracesys_nosys:
382 ldo -ENOSYS(%r0),%r28 /* set errno */
383
384 /* Do *not* call this function on the gateway page, because it
385 makes a direct call to syscall_trace. */
386
387tracesys_exit:
388 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
389 LDREG TI_TASK(%r1), %r1
390#ifdef CONFIG_64BIT
391 ldo -16(%r30),%r29 /* Reference param save area */
392#endif
393 ldo TASK_REGS(%r1),%r26
394 BL do_syscall_trace_exit,%r2
395 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */
396 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
397 LDREG TI_TASK(%r1), %r1
398 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */
399
400 ldil L%syscall_exit,%r1
401 be,n R%syscall_exit(%sr7,%r1)
402
403.Ltrace_rt_sigreturn:
404 comib,<> 0,%r25,.Ltrace_in_syscall
405 ldil L%tracesys_sigexit,%r2
406 be 0(%sr7,%r19)
407 ldo R%tracesys_sigexit(%r2),%r2
408
409tracesys_sigexit:
410 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
411 LDREG TI_TASK(%r1), %r1
412#ifdef CONFIG_64BIT
413 ldo -16(%r30),%r29 /* Reference param save area */
414#endif
415 BL do_syscall_trace_exit,%r2
416 ldo TASK_REGS(%r1),%r26
417
418 ldil L%syscall_exit_rfi,%r1
419 be,n R%syscall_exit_rfi(%sr7,%r1)
420
421
422 /*********************************************************
423 32/64-bit Light-Weight-Syscall ABI
424
425 * - Indicates a hint for userspace inline asm
426 implementations.
427
428 Syscall number (caller-saves)
429 - %r20
430 * In asm clobber.
431
432 Argument registers (caller-saves)
433 - %r26, %r25, %r24, %r23, %r22
434 * In asm input.
435
436 Return registers (caller-saves)
437 - %r28 (return), %r21 (errno)
438 * In asm output.
439
440 Caller-saves registers
441 - %r1, %r27, %r29
442 - %r2 (return pointer)
443 - %r31 (ble link register)
444 * In asm clobber.
445
446 Callee-saves registers
447 - %r3-%r18
448 - %r30 (stack pointer)
449 * Not in asm clobber.
450
451 If userspace is 32-bit:
452 Callee-saves registers
453 - %r19 (32-bit PIC register)
454
455 Differences from 32-bit calling convention:
456 - Syscall number in %r20
457 - Additional argument register %r22 (arg4)
458 - Callee-saves %r19.
459
460 If userspace is 64-bit:
461 Callee-saves registers
462 - %r27 (64-bit PIC register)
463
464 Differences from 64-bit calling convention:
465 - Syscall number in %r20
466 - Additional argument register %r22 (arg4)
467 - Callee-saves %r27.
468
469 Error codes returned by entry path:
470
471 ENOSYS - r20 was an invalid LWS number.
472
473 *********************************************************/
474lws_start:
475
476#ifdef CONFIG_64BIT
477 ssm PSW_SM_W, %r1
478 extrd,u %r1,PSW_W_BIT,1,%r1
479 /* sp must be aligned on 4, so deposit the W bit setting into
480 * the bottom of sp temporarily */
481 or,ev %r1,%r30,%r30
482
483 /* Clip LWS number to a 32-bit value for 32-bit processes */
484 depdi 0, 31, 32, %r20
485#endif
486
487 /* Is the lws entry number valid? */
488 comiclr,>> __NR_lws_entries, %r20, %r0
489 b,n lws_exit_nosys
490
491 /* Load table start */
492 ldil L%lws_table, %r1
493 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
494 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */
495
496 /* Jump to lws, lws table pointers already relocated */
497 be,n 0(%sr2,%r21)
498
499lws_exit_nosys:
500 ldo -ENOSYS(%r0),%r21 /* set errno */
501 /* Fall through: Return to userspace */
502
503lws_exit:
504#ifdef CONFIG_64BIT
505 /* decide whether to reset the wide mode bit
506 *
507 * For a syscall, the W bit is stored in the lowest bit
508 * of sp. Extract it and reset W if it is zero */
509 extrd,u,*<> %r30,63,1,%r1
510 rsm PSW_SM_W, %r0
511 /* now reset the lowest bit of sp if it was set */
512 xor %r30,%r1,%r30
513#endif
514 be,n 0(%sr7, %r31)
515
516
517
518 /***************************************************
519 Implementing 32bit CAS as an atomic operation:
520
521 %r26 - Address to examine
522 %r25 - Old value to check (old)
523 %r24 - New value to set (new)
524 %r28 - Return prev through this register.
525 %r21 - Kernel error code
526
527 If debugging is DISabled:
528
529 %r21 has the following meanings:
530
531 EAGAIN - CAS is busy, ldcw failed, try again.
532 EFAULT - Read or write failed.
533
534 If debugging is enabled:
535
536 EDEADLOCK - CAS called recursively.
537 EAGAIN && r28 == 1 - CAS is busy. Lock contended.
538 EAGAIN && r28 == 2 - CAS is busy. ldcw failed.
539 EFAULT - Read or write failed.
540
541 Scratch: r20, r28, r1
542
543 ****************************************************/
544
545 /* Do not enable LWS debugging */
546#define ENABLE_LWS_DEBUG 0
547
548 /* ELF64 Process entry path */
549lws_compare_and_swap64:
550#ifdef CONFIG_64BIT
551 b,n lws_compare_and_swap
552#else
553 /* If we are not a 64-bit kernel, then we don't
554 * have 64-bit input registers, and calling
555 * the 64-bit LWS CAS returns ENOSYS.
556 */
557 b,n lws_exit_nosys
558#endif
559
560 /* ELF32 Process entry path */
561lws_compare_and_swap32:
562#ifdef CONFIG_64BIT
563 /* Clip all the input registers */
564 depdi 0, 31, 32, %r26
565 depdi 0, 31, 32, %r25
566 depdi 0, 31, 32, %r24
567#endif
568
569lws_compare_and_swap:
570 /* Load start of lock table */
571 ldil L%lws_lock_start, %r20
572 ldo R%lws_lock_start(%r20), %r28
573
574 /* Extract four bits from r26 and hash lock (Bits 4-7) */
575 extru %r26, 27, 4, %r20
576
577 /* Find lock to use, the hash is either one of 0 to
578 15, multiplied by 16 (keep it 16-byte aligned)
579 and add to the lock table offset. */
580 shlw %r20, 4, %r20
581 add %r20, %r28, %r20
582
583# if ENABLE_LWS_DEBUG
584 /*
585 DEBUG, check for deadlock!
586 If the thread register values are the same
587 then we were the one that locked it last and
588 this is a recurisve call that will deadlock.
589 We *must* giveup this call and fail.
590 */
591 ldw 4(%sr2,%r20), %r28 /* Load thread register */
592 /* WARNING: If cr27 cycles to the same value we have problems */
593 mfctl %cr27, %r21 /* Get current thread register */
594 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */
595 b lws_exit /* Return error! */
596 ldo -EDEADLOCK(%r0), %r21
597cas_lock:
598 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */
599 ldo 1(%r0), %r28 /* 1st case */
600 b lws_exit /* Contended... */
601 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
602cas_nocontend:
603# endif
604/* ENABLE_LWS_DEBUG */
605
606 rsm PSW_SM_I, %r0 /* Disable interrupts */
607 /* COW breaks can cause contention on UP systems */
608 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
609 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */
610cas_wouldblock:
611 ldo 2(%r0), %r28 /* 2nd case */
612 ssm PSW_SM_I, %r0
613 b lws_exit /* Contended... */
614 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
615
616 /*
617 prev = *addr;
618 if ( prev == old )
619 *addr = new;
620 return prev;
621 */
622
623 /* NOTES:
624 This all works becuse intr_do_signal
625 and schedule both check the return iasq
626 and see that we are on the kernel page
627 so this process is never scheduled off
628 or is ever sent any signal of any sort,
629 thus it is wholly atomic from usrspaces
630 perspective
631 */
632cas_action:
633#if defined CONFIG_SMP && ENABLE_LWS_DEBUG
634 /* DEBUG */
635 mfctl %cr27, %r1
636 stw %r1, 4(%sr2,%r20)
637#endif
638 /* The load and store could fail */
6391: ldw 0(%r26), %r28
640 sub,<> %r28, %r25, %r0
6412: stw %r24, 0(%r26)
642 /* Free lock */
643#ifdef CONFIG_SMP
64498: LDCW 0(%sr2,%r20), %r1 /* Barrier */
64599: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
646#endif
647 stw %r20, 0(%sr2,%r20)
648#if ENABLE_LWS_DEBUG
649 /* Clear thread register indicator */
650 stw %r0, 4(%sr2,%r20)
651#endif
652 /* Enable interrupts */
653 ssm PSW_SM_I, %r0
654 /* Return to userspace, set no error */
655 b lws_exit
656 copy %r0, %r21
657
6583:
659 /* Error occurred on load or store */
660 /* Free lock */
661#ifdef CONFIG_SMP
66298: LDCW 0(%sr2,%r20), %r1 /* Barrier */
66399: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
664#endif
665 stw %r20, 0(%sr2,%r20)
666#if ENABLE_LWS_DEBUG
667 stw %r0, 4(%sr2,%r20)
668#endif
669 ssm PSW_SM_I, %r0
670 b lws_exit
671 ldo -EFAULT(%r0),%r21 /* set errno */
672 nop
673 nop
674 nop
675 nop
676
677 /* Two exception table entries, one for the load,
678 the other for the store. Either return -EFAULT.
679 Each of the entries must be relocated. */
680 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 3b-linux_gateway_page)
681 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 3b-linux_gateway_page)
682
683
684 /***************************************************
685 New CAS implementation which uses pointers and variable size
686 information. The value pointed by old and new MUST NOT change
687 while performing CAS. The lock only protect the value at %r26.
688
689 %r26 - Address to examine
690 %r25 - Pointer to the value to check (old)
691 %r24 - Pointer to the value to set (new)
692 %r23 - Size of the variable (0/1/2/3 for 8/16/32/64 bit)
693 %r28 - Return non-zero on failure
694 %r21 - Kernel error code
695
696 %r21 has the following meanings:
697
698 EAGAIN - CAS is busy, ldcw failed, try again.
699 EFAULT - Read or write failed.
700
701 Scratch: r20, r22, r28, r29, r1, fr4 (32bit for 64bit CAS only)
702
703 ****************************************************/
704
705 /* ELF32 Process entry path */
706lws_compare_and_swap_2:
707#ifdef CONFIG_64BIT
708 /* Clip the input registers. We don't need to clip %r23 as we
709 only use it for word operations */
710 depdi 0, 31, 32, %r26
711 depdi 0, 31, 32, %r25
712 depdi 0, 31, 32, %r24
713#endif
714
715 /* Check the validity of the size pointer */
716 subi,>>= 3, %r23, %r0
717 b,n lws_exit_nosys
718
719 /* Jump to the functions which will load the old and new values into
720 registers depending on the their size */
721 shlw %r23, 2, %r29
722 blr %r29, %r0
723 nop
724
725 /* 8bit load */
7264: ldb 0(%r25), %r25
727 b cas2_lock_start
7285: ldb 0(%r24), %r24
729 nop
730 nop
731 nop
732 nop
733 nop
734
735 /* 16bit load */
7366: ldh 0(%r25), %r25
737 b cas2_lock_start
7387: ldh 0(%r24), %r24
739 nop
740 nop
741 nop
742 nop
743 nop
744
745 /* 32bit load */
7468: ldw 0(%r25), %r25
747 b cas2_lock_start
7489: ldw 0(%r24), %r24
749 nop
750 nop
751 nop
752 nop
753 nop
754
755 /* 64bit load */
756#ifdef CONFIG_64BIT
75710: ldd 0(%r25), %r25
75811: ldd 0(%r24), %r24
759#else
760 /* Load old value into r22/r23 - high/low */
76110: ldw 0(%r25), %r22
76211: ldw 4(%r25), %r23
763 /* Load new value into fr4 for atomic store later */
76412: flddx 0(%r24), %fr4
765#endif
766
767cas2_lock_start:
768 /* Load start of lock table */
769 ldil L%lws_lock_start, %r20
770 ldo R%lws_lock_start(%r20), %r28
771
772 /* Extract four bits from r26 and hash lock (Bits 4-7) */
773 extru %r26, 27, 4, %r20
774
775 /* Find lock to use, the hash is either one of 0 to
776 15, multiplied by 16 (keep it 16-byte aligned)
777 and add to the lock table offset. */
778 shlw %r20, 4, %r20
779 add %r20, %r28, %r20
780
781 rsm PSW_SM_I, %r0 /* Disable interrupts */
782 /* COW breaks can cause contention on UP systems */
783 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
784 cmpb,<>,n %r0, %r28, cas2_action /* Did we get it? */
785cas2_wouldblock:
786 ldo 2(%r0), %r28 /* 2nd case */
787 ssm PSW_SM_I, %r0
788 b lws_exit /* Contended... */
789 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
790
791 /*
792 prev = *addr;
793 if ( prev == old )
794 *addr = new;
795 return prev;
796 */
797
798 /* NOTES:
799 This all works becuse intr_do_signal
800 and schedule both check the return iasq
801 and see that we are on the kernel page
802 so this process is never scheduled off
803 or is ever sent any signal of any sort,
804 thus it is wholly atomic from usrspaces
805 perspective
806 */
807cas2_action:
808 /* Jump to the correct function */
809 blr %r29, %r0
810 /* Set %r28 as non-zero for now */
811 ldo 1(%r0),%r28
812
813 /* 8bit CAS */
81413: ldb 0(%r26), %r29
815 sub,= %r29, %r25, %r0
816 b,n cas2_end
81714: stb %r24, 0(%r26)
818 b cas2_end
819 copy %r0, %r28
820 nop
821 nop
822
823 /* 16bit CAS */
82415: ldh 0(%r26), %r29
825 sub,= %r29, %r25, %r0
826 b,n cas2_end
82716: sth %r24, 0(%r26)
828 b cas2_end
829 copy %r0, %r28
830 nop
831 nop
832
833 /* 32bit CAS */
83417: ldw 0(%r26), %r29
835 sub,= %r29, %r25, %r0
836 b,n cas2_end
83718: stw %r24, 0(%r26)
838 b cas2_end
839 copy %r0, %r28
840 nop
841 nop
842
843 /* 64bit CAS */
844#ifdef CONFIG_64BIT
84519: ldd 0(%r26), %r29
846 sub,*= %r29, %r25, %r0
847 b,n cas2_end
84820: std %r24, 0(%r26)
849 copy %r0, %r28
850#else
851 /* Compare first word */
85219: ldw 0(%r26), %r29
853 sub,= %r29, %r22, %r0
854 b,n cas2_end
855 /* Compare second word */
85620: ldw 4(%r26), %r29
857 sub,= %r29, %r23, %r0
858 b,n cas2_end
859 /* Perform the store */
86021: fstdx %fr4, 0(%r26)
861 copy %r0, %r28
862#endif
863
864cas2_end:
865 /* Free lock */
866#ifdef CONFIG_SMP
86798: LDCW 0(%sr2,%r20), %r1 /* Barrier */
86899: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
869#endif
870 stw %r20, 0(%sr2,%r20)
871 /* Enable interrupts */
872 ssm PSW_SM_I, %r0
873 /* Return to userspace, set no error */
874 b lws_exit
875 copy %r0, %r21
876
87722:
878 /* Error occurred on load or store */
879 /* Free lock */
880#ifdef CONFIG_SMP
88198: LDCW 0(%sr2,%r20), %r1 /* Barrier */
88299: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
883#endif
884 stw %r20, 0(%sr2,%r20)
885 ssm PSW_SM_I, %r0
886 ldo 1(%r0),%r28
887 b lws_exit
888 ldo -EFAULT(%r0),%r21 /* set errno */
889 nop
890 nop
891 nop
892
893 /* Exception table entries, for the load and store, return EFAULT.
894 Each of the entries must be relocated. */
895 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 22b-linux_gateway_page)
896 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 22b-linux_gateway_page)
897 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 22b-linux_gateway_page)
898 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 22b-linux_gateway_page)
899 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 22b-linux_gateway_page)
900 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 22b-linux_gateway_page)
901 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 22b-linux_gateway_page)
902 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 22b-linux_gateway_page)
903 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 22b-linux_gateway_page)
904 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 22b-linux_gateway_page)
905 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 22b-linux_gateway_page)
906 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 22b-linux_gateway_page)
907 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 22b-linux_gateway_page)
908 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 22b-linux_gateway_page)
909 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 22b-linux_gateway_page)
910 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 22b-linux_gateway_page)
911#ifndef CONFIG_64BIT
912 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 22b-linux_gateway_page)
913 ASM_EXCEPTIONTABLE_ENTRY(21b-linux_gateway_page, 22b-linux_gateway_page)
914#endif
915
916 /* Make sure nothing else is placed on this page */
917 .align PAGE_SIZE
918END(linux_gateway_page)
919ENTRY(end_linux_gateway_page)
920
921 /* Relocate symbols assuming linux_gateway_page is mapped
922 to virtual address 0x0 */
923
924#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page)
925
926 .section .rodata,"a"
927
928 .align 8
929 /* Light-weight-syscall table */
930 /* Start of lws table. */
931ENTRY(lws_table)
932 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic 32bit CAS */
933 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic 32bit CAS */
934 LWS_ENTRY(compare_and_swap_2) /* 2 - ELF32 Atomic 64bit CAS */
935END(lws_table)
936 /* End of lws table */
937
938#define __SYSCALL(nr, entry, nargs) ASM_ULONG_INSN entry
939 .align 8
940ENTRY(sys_call_table)
941 .export sys_call_table,data
942#ifdef CONFIG_64BIT
943#include <asm/syscall_table_c32.h> /* Compat syscalls */
944#else
945#include <asm/syscall_table_32.h> /* 32-bit native syscalls */
946#endif
947END(sys_call_table)
948
949#ifdef CONFIG_64BIT
950 .align 8
951ENTRY(sys_call_table64)
952#include <asm/syscall_table_64.h> /* 64-bit native syscalls */
953END(sys_call_table64)
954#endif
955#undef __SYSCALL
956
957 /*
958 All light-weight-syscall atomic operations
959 will use this set of locks
960
961 NOTE: The lws_lock_start symbol must be
962 at least 16-byte aligned for safe use
963 with ldcw.
964 */
965 .section .data
966 .align L1_CACHE_BYTES
967ENTRY(lws_lock_start)
968 /* lws locks */
969 .rept 16
970 /* Keep locks aligned at 16-bytes */
971 .word 1
972 .word 0
973 .word 0
974 .word 0
975 .endr
976END(lws_lock_start)
977 .previous
978
979.end
980
981
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@bofh.ai>
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
43#include <linux/linkage.h>
44
45 /* We fill the empty parts of the gateway page with
46 * something that will kill the kernel or a
47 * userspace application.
48 */
49#define KILL_INSN break 0,0
50
51 .level LEVEL
52
53 .text
54
55 .import syscall_exit,code
56 .import syscall_exit_rfi,code
57
58 /* Linux gateway page is aliased to virtual page 0 in the kernel
59 * address space. Since it is a gateway page it cannot be
60 * dereferenced, so null pointers will still fault. We start
61 * the actual entry point at 0x100. We put break instructions
62 * at the beginning of the page to trap null indirect function
63 * pointers.
64 */
65
66 .align PAGE_SIZE
67ENTRY(linux_gateway_page)
68
69 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */
70 .rept 44
71 KILL_INSN
72 .endr
73
74 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */
75 /* Light-weight-syscall entry must always be located at 0xb0 */
76 /* WARNING: Keep this number updated with table size changes */
77#define __NR_lws_entries (3)
78
79lws_entry:
80 gate lws_start, %r0 /* increase privilege */
81 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
82
83 /* Fill from 0xb8 to 0xe0 */
84 .rept 10
85 KILL_INSN
86 .endr
87
88 /* This function MUST be located at 0xe0 for glibc's threading
89 mechanism to work. DO NOT MOVE THIS CODE EVER! */
90set_thread_pointer:
91 gate .+8, %r0 /* increase privilege */
92 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */
93 be 0(%sr7,%r31) /* return to user space */
94 mtctl %r26, %cr27 /* move arg0 to the control register */
95
96 /* Increase the chance of trapping if random jumps occur to this
97 address, fill from 0xf0 to 0x100 */
98 .rept 4
99 KILL_INSN
100 .endr
101
102/* This address must remain fixed at 0x100 for glibc's syscalls to work */
103 .align LINUX_GATEWAY_ADDR
104linux_gateway_entry:
105 gate .+8, %r0 /* become privileged */
106 mtsp %r0,%sr4 /* get kernel space into sr4 */
107 mtsp %r0,%sr5 /* get kernel space into sr5 */
108 mtsp %r0,%sr6 /* get kernel space into sr6 */
109
110#ifdef CONFIG_64BIT
111 /* for now we can *always* set the W bit on entry to the syscall
112 * since we don't support wide userland processes. We could
113 * also save the current SM other than in r0 and restore it on
114 * exit from the syscall, and also use that value to know
115 * whether to do narrow or wide syscalls. -PB
116 */
117 ssm PSW_SM_W, %r1
118 extrd,u %r1,PSW_W_BIT,1,%r1
119 /* sp must be aligned on 4, so deposit the W bit setting into
120 * the bottom of sp temporarily */
121 or,ev %r1,%r30,%r30
122 b,n 1f
123 /* The top halves of argument registers must be cleared on syscall
124 * entry from narrow executable.
125 */
126 depdi 0, 31, 32, %r26
127 depdi 0, 31, 32, %r25
128 depdi 0, 31, 32, %r24
129 depdi 0, 31, 32, %r23
130 depdi 0, 31, 32, %r22
131 depdi 0, 31, 32, %r21
1321:
133#endif
134
135 /* We use a rsm/ssm pair to prevent sr3 from being clobbered
136 * by external interrupts.
137 */
138 mfsp %sr7,%r1 /* save user sr7 */
139 rsm PSW_SM_I, %r0 /* disable interrupts */
140 mtsp %r1,%sr3 /* and store it in sr3 */
141
142 mfctl %cr30,%r1
143 xor %r1,%r30,%r30 /* ye olde xor trick */
144 xor %r1,%r30,%r1
145 xor %r1,%r30,%r30
146
147 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */
148
149 /* N.B.: It is critical that we don't set sr7 to 0 until r30
150 * contains a valid kernel stack pointer. It is also
151 * critical that we don't start using the kernel stack
152 * until after sr7 has been set to 0.
153 */
154
155 mtsp %r0,%sr7 /* get kernel space into sr7 */
156 ssm PSW_SM_I, %r0 /* enable interrupts */
157 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */
158 mfctl %cr30,%r1 /* get task ptr in %r1 */
159 LDREG TI_TASK(%r1),%r1
160
161 /* Save some registers for sigcontext and potential task
162 switch (see entry.S for the details of which ones are
163 saved/restored). TASK_PT_PSW is zeroed so we can see whether
164 a process is on a syscall or not. For an interrupt the real
165 PSW value is stored. This is needed for gdb and sys_ptrace. */
166 STREG %r0, TASK_PT_PSW(%r1)
167 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */
168 STREG %r19, TASK_PT_GR19(%r1)
169
170 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */
171#ifdef CONFIG_64BIT
172 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */
173#if 0
174 xor %r19,%r2,%r2 /* clear bottom bit */
175 depd,z %r19,1,1,%r19
176 std %r19,TASK_PT_PSW(%r1)
177#endif
178#endif
179 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */
180
181 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */
182 STREG %r21, TASK_PT_GR21(%r1)
183 STREG %r22, TASK_PT_GR22(%r1)
184 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */
185 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */
186 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */
187 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */
188 STREG %r27, TASK_PT_GR27(%r1) /* user dp */
189 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */
190 STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */
191 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */
192 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */
193
194 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */
195 save_fp %r27 /* or potential task switch */
196
197 mfctl %cr11, %r27 /* i.e. SAR */
198 STREG %r27, TASK_PT_SAR(%r1)
199
200 loadgp
201
202#ifdef CONFIG_64BIT
203 ldo -16(%r30),%r29 /* Reference param save area */
204 copy %r19,%r2 /* W bit back to r2 */
205#else
206 /* no need to save these on stack in wide mode because the first 8
207 * args are passed in registers */
208 stw %r22, -52(%r30) /* 5th argument */
209 stw %r21, -56(%r30) /* 6th argument */
210#endif
211
212 /* Are we being ptraced? */
213 mfctl %cr30, %r1
214 LDREG TI_FLAGS(%r1),%r1
215 ldi _TIF_SYSCALL_TRACE_MASK, %r19
216 and,COND(=) %r1, %r19, %r0
217 b,n .Ltracesys
218
219 /* Note! We cannot use the syscall table that is mapped
220 nearby since the gateway page is mapped execute-only. */
221
222#ifdef CONFIG_64BIT
223 ldil L%sys_call_table, %r1
224 or,= %r2,%r2,%r2
225 addil L%(sys_call_table64-sys_call_table), %r1
226 ldo R%sys_call_table(%r1), %r19
227 or,= %r2,%r2,%r2
228 ldo R%sys_call_table64(%r1), %r19
229#else
230 ldil L%sys_call_table, %r1
231 ldo R%sys_call_table(%r1), %r19
232#endif
233 comiclr,>> __NR_Linux_syscalls, %r20, %r0
234 b,n .Lsyscall_nosys
235
236 LDREGX %r20(%r19), %r19
237
238 /* If this is a sys_rt_sigreturn call, and the signal was received
239 * when not in_syscall, then we want to return via syscall_exit_rfi,
240 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
241 * trampoline code in signal.c).
242 */
243 ldi __NR_rt_sigreturn,%r2
244 comb,= %r2,%r20,.Lrt_sigreturn
245.Lin_syscall:
246 ldil L%syscall_exit,%r2
247 be 0(%sr7,%r19)
248 ldo R%syscall_exit(%r2),%r2
249.Lrt_sigreturn:
250 comib,<> 0,%r25,.Lin_syscall
251 ldil L%syscall_exit_rfi,%r2
252 be 0(%sr7,%r19)
253 ldo R%syscall_exit_rfi(%r2),%r2
254
255 /* Note! Because we are not running where we were linked, any
256 calls to functions external to this file must be indirect. To
257 be safe, we apply the opposite rule to functions within this
258 file, with local labels given to them to ensure correctness. */
259
260.Lsyscall_nosys:
261syscall_nosys:
262 ldil L%syscall_exit,%r1
263 be R%syscall_exit(%sr7,%r1)
264 ldo -ENOSYS(%r0),%r28 /* set errno */
265
266
267/* Warning! This trace code is a virtual duplicate of the code above so be
268 * sure to maintain both! */
269.Ltracesys:
270tracesys:
271 /* Need to save more registers so the debugger can see where we
272 * are. This saves only the lower 8 bits of PSW, so that the C
273 * bit is still clear on syscalls, and the D bit is set if this
274 * full register save path has been executed. We check the D
275 * bit on syscall_return_rfi to determine which registers to
276 * restore. An interrupt results in a full PSW saved with the
277 * C bit set, a non-straced syscall entry results in C and D clear
278 * in the saved PSW.
279 */
280 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
281 LDREG TI_TASK(%r1), %r1
282 ssm 0,%r2
283 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */
284 mfsp %sr0,%r2
285 STREG %r2,TASK_PT_SR0(%r1)
286 mfsp %sr1,%r2
287 STREG %r2,TASK_PT_SR1(%r1)
288 mfsp %sr2,%r2
289 STREG %r2,TASK_PT_SR2(%r1)
290 mfsp %sr3,%r2
291 STREG %r2,TASK_PT_SR3(%r1)
292 STREG %r2,TASK_PT_SR4(%r1)
293 STREG %r2,TASK_PT_SR5(%r1)
294 STREG %r2,TASK_PT_SR6(%r1)
295 STREG %r2,TASK_PT_SR7(%r1)
296 STREG %r2,TASK_PT_IASQ0(%r1)
297 STREG %r2,TASK_PT_IASQ1(%r1)
298 LDREG TASK_PT_GR31(%r1),%r2
299 STREG %r2,TASK_PT_IAOQ0(%r1)
300 ldo 4(%r2),%r2
301 STREG %r2,TASK_PT_IAOQ1(%r1)
302 ldo TASK_REGS(%r1),%r2
303 /* reg_save %r2 */
304 STREG %r3,PT_GR3(%r2)
305 STREG %r4,PT_GR4(%r2)
306 STREG %r5,PT_GR5(%r2)
307 STREG %r6,PT_GR6(%r2)
308 STREG %r7,PT_GR7(%r2)
309 STREG %r8,PT_GR8(%r2)
310 STREG %r9,PT_GR9(%r2)
311 STREG %r10,PT_GR10(%r2)
312 STREG %r11,PT_GR11(%r2)
313 STREG %r12,PT_GR12(%r2)
314 STREG %r13,PT_GR13(%r2)
315 STREG %r14,PT_GR14(%r2)
316 STREG %r15,PT_GR15(%r2)
317 STREG %r16,PT_GR16(%r2)
318 STREG %r17,PT_GR17(%r2)
319 STREG %r18,PT_GR18(%r2)
320 /* Finished saving things for the debugger */
321
322 copy %r2,%r26
323 ldil L%do_syscall_trace_enter,%r1
324 ldil L%tracesys_next,%r2
325 be R%do_syscall_trace_enter(%sr7,%r1)
326 ldo R%tracesys_next(%r2),%r2
327
328tracesys_next:
329 /* do_syscall_trace_enter either returned the syscallno, or -1L,
330 * so we skip restoring the PT_GR20 below, since we pulled it from
331 * task->thread.regs.gr[20] above.
332 */
333 copy %ret0,%r20
334 ldil L%sys_call_table,%r1
335 ldo R%sys_call_table(%r1), %r19
336
337 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
338 LDREG TI_TASK(%r1), %r1
339 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return value */
340 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */
341 LDREG TASK_PT_GR25(%r1), %r25
342 LDREG TASK_PT_GR24(%r1), %r24
343 LDREG TASK_PT_GR23(%r1), %r23
344 LDREG TASK_PT_GR22(%r1), %r22
345 LDREG TASK_PT_GR21(%r1), %r21
346#ifdef CONFIG_64BIT
347 ldo -16(%r30),%r29 /* Reference param save area */
348#else
349 stw %r22, -52(%r30) /* 5th argument */
350 stw %r21, -56(%r30) /* 6th argument */
351#endif
352
353 cmpib,COND(=),n -1,%r20,tracesys_exit /* seccomp may have returned -1 */
354 comiclr,>> __NR_Linux_syscalls, %r20, %r0
355 b,n .Ltracesys_nosys
356
357 LDREGX %r20(%r19), %r19
358
359 /* If this is a sys_rt_sigreturn call, and the signal was received
360 * when not in_syscall, then we want to return via syscall_exit_rfi,
361 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see
362 * trampoline code in signal.c).
363 */
364 ldi __NR_rt_sigreturn,%r2
365 comb,= %r2,%r20,.Ltrace_rt_sigreturn
366.Ltrace_in_syscall:
367 ldil L%tracesys_exit,%r2
368 be 0(%sr7,%r19)
369 ldo R%tracesys_exit(%r2),%r2
370
371.Ltracesys_nosys:
372 ldo -ENOSYS(%r0),%r28 /* set errno */
373
374 /* Do *not* call this function on the gateway page, because it
375 makes a direct call to syscall_trace. */
376
377tracesys_exit:
378 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
379 LDREG TI_TASK(%r1), %r1
380#ifdef CONFIG_64BIT
381 ldo -16(%r30),%r29 /* Reference param save area */
382#endif
383 ldo TASK_REGS(%r1),%r26
384 BL do_syscall_trace_exit,%r2
385 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */
386 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
387 LDREG TI_TASK(%r1), %r1
388 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */
389
390 ldil L%syscall_exit,%r1
391 be,n R%syscall_exit(%sr7,%r1)
392
393.Ltrace_rt_sigreturn:
394 comib,<> 0,%r25,.Ltrace_in_syscall
395 ldil L%tracesys_sigexit,%r2
396 be 0(%sr7,%r19)
397 ldo R%tracesys_sigexit(%r2),%r2
398
399tracesys_sigexit:
400 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */
401 LDREG TI_TASK(%r1), %r1
402#ifdef CONFIG_64BIT
403 ldo -16(%r30),%r29 /* Reference param save area */
404#endif
405 BL do_syscall_trace_exit,%r2
406 ldo TASK_REGS(%r1),%r26
407
408 ldil L%syscall_exit_rfi,%r1
409 be,n R%syscall_exit_rfi(%sr7,%r1)
410
411
412 /*********************************************************
413 32/64-bit Light-Weight-Syscall ABI
414
415 * - Indicates a hint for userspace inline asm
416 implementations.
417
418 Syscall number (caller-saves)
419 - %r20
420 * In asm clobber.
421
422 Argument registers (caller-saves)
423 - %r26, %r25, %r24, %r23, %r22
424 * In asm input.
425
426 Return registers (caller-saves)
427 - %r28 (return), %r21 (errno)
428 * In asm output.
429
430 Caller-saves registers
431 - %r1, %r27, %r29
432 - %r2 (return pointer)
433 - %r31 (ble link register)
434 * In asm clobber.
435
436 Callee-saves registers
437 - %r3-%r18
438 - %r30 (stack pointer)
439 * Not in asm clobber.
440
441 If userspace is 32-bit:
442 Callee-saves registers
443 - %r19 (32-bit PIC register)
444
445 Differences from 32-bit calling convention:
446 - Syscall number in %r20
447 - Additional argument register %r22 (arg4)
448 - Callee-saves %r19.
449
450 If userspace is 64-bit:
451 Callee-saves registers
452 - %r27 (64-bit PIC register)
453
454 Differences from 64-bit calling convention:
455 - Syscall number in %r20
456 - Additional argument register %r22 (arg4)
457 - Callee-saves %r27.
458
459 Error codes returned by entry path:
460
461 ENOSYS - r20 was an invalid LWS number.
462
463 *********************************************************/
464lws_start:
465
466#ifdef CONFIG_64BIT
467 /* FIXME: If we are a 64-bit kernel just
468 * turn this on unconditionally.
469 */
470 ssm PSW_SM_W, %r1
471 extrd,u %r1,PSW_W_BIT,1,%r1
472 /* sp must be aligned on 4, so deposit the W bit setting into
473 * the bottom of sp temporarily */
474 or,ev %r1,%r30,%r30
475
476 /* Clip LWS number to a 32-bit value always */
477 depdi 0, 31, 32, %r20
478#endif
479
480 /* Is the lws entry number valid? */
481 comiclr,>> __NR_lws_entries, %r20, %r0
482 b,n lws_exit_nosys
483
484 /* Load table start */
485 ldil L%lws_table, %r1
486 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
487 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */
488
489 /* Jump to lws, lws table pointers already relocated */
490 be,n 0(%sr2,%r21)
491
492lws_exit_nosys:
493 ldo -ENOSYS(%r0),%r21 /* set errno */
494 /* Fall through: Return to userspace */
495
496lws_exit:
497#ifdef CONFIG_64BIT
498 /* decide whether to reset the wide mode bit
499 *
500 * For a syscall, the W bit is stored in the lowest bit
501 * of sp. Extract it and reset W if it is zero */
502 extrd,u,*<> %r30,63,1,%r1
503 rsm PSW_SM_W, %r0
504 /* now reset the lowest bit of sp if it was set */
505 xor %r30,%r1,%r30
506#endif
507 be,n 0(%sr7, %r31)
508
509
510
511 /***************************************************
512 Implementing 32bit CAS as an atomic operation:
513
514 %r26 - Address to examine
515 %r25 - Old value to check (old)
516 %r24 - New value to set (new)
517 %r28 - Return prev through this register.
518 %r21 - Kernel error code
519
520 If debugging is DISabled:
521
522 %r21 has the following meanings:
523
524 EAGAIN - CAS is busy, ldcw failed, try again.
525 EFAULT - Read or write failed.
526
527 If debugging is enabled:
528
529 EDEADLOCK - CAS called recursively.
530 EAGAIN && r28 == 1 - CAS is busy. Lock contended.
531 EAGAIN && r28 == 2 - CAS is busy. ldcw failed.
532 EFAULT - Read or write failed.
533
534 Scratch: r20, r28, r1
535
536 ****************************************************/
537
538 /* Do not enable LWS debugging */
539#define ENABLE_LWS_DEBUG 0
540
541 /* ELF64 Process entry path */
542lws_compare_and_swap64:
543#ifdef CONFIG_64BIT
544 b,n lws_compare_and_swap
545#else
546 /* If we are not a 64-bit kernel, then we don't
547 * have 64-bit input registers, and calling
548 * the 64-bit LWS CAS returns ENOSYS.
549 */
550 b,n lws_exit_nosys
551#endif
552
553 /* ELF32 Process entry path */
554lws_compare_and_swap32:
555#ifdef CONFIG_64BIT
556 /* Clip all the input registers */
557 depdi 0, 31, 32, %r26
558 depdi 0, 31, 32, %r25
559 depdi 0, 31, 32, %r24
560#endif
561
562lws_compare_and_swap:
563 /* Load start of lock table */
564 ldil L%lws_lock_start, %r20
565 ldo R%lws_lock_start(%r20), %r28
566
567 /* Extract four bits from r26 and hash lock (Bits 4-7) */
568 extru %r26, 27, 4, %r20
569
570 /* Find lock to use, the hash is either one of 0 to
571 15, multiplied by 16 (keep it 16-byte aligned)
572 and add to the lock table offset. */
573 shlw %r20, 4, %r20
574 add %r20, %r28, %r20
575
576# if ENABLE_LWS_DEBUG
577 /*
578 DEBUG, check for deadlock!
579 If the thread register values are the same
580 then we were the one that locked it last and
581 this is a recurisve call that will deadlock.
582 We *must* giveup this call and fail.
583 */
584 ldw 4(%sr2,%r20), %r28 /* Load thread register */
585 /* WARNING: If cr27 cycles to the same value we have problems */
586 mfctl %cr27, %r21 /* Get current thread register */
587 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */
588 b lws_exit /* Return error! */
589 ldo -EDEADLOCK(%r0), %r21
590cas_lock:
591 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */
592 ldo 1(%r0), %r28 /* 1st case */
593 b lws_exit /* Contended... */
594 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
595cas_nocontend:
596# endif
597/* ENABLE_LWS_DEBUG */
598
599 rsm PSW_SM_I, %r0 /* Disable interrupts */
600 /* COW breaks can cause contention on UP systems */
601 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
602 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */
603cas_wouldblock:
604 ldo 2(%r0), %r28 /* 2nd case */
605 ssm PSW_SM_I, %r0
606 b lws_exit /* Contended... */
607 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
608
609 /*
610 prev = *addr;
611 if ( prev == old )
612 *addr = new;
613 return prev;
614 */
615
616 /* NOTES:
617 This all works becuse intr_do_signal
618 and schedule both check the return iasq
619 and see that we are on the kernel page
620 so this process is never scheduled off
621 or is ever sent any signal of any sort,
622 thus it is wholly atomic from usrspaces
623 perspective
624 */
625cas_action:
626#if defined CONFIG_SMP && ENABLE_LWS_DEBUG
627 /* DEBUG */
628 mfctl %cr27, %r1
629 stw %r1, 4(%sr2,%r20)
630#endif
631 /* The load and store could fail */
6321: ldw,ma 0(%r26), %r28
633 sub,<> %r28, %r25, %r0
6342: stw,ma %r24, 0(%r26)
635 /* Free lock */
636 stw,ma %r20, 0(%sr2,%r20)
637#if ENABLE_LWS_DEBUG
638 /* Clear thread register indicator */
639 stw %r0, 4(%sr2,%r20)
640#endif
641 /* Enable interrupts */
642 ssm PSW_SM_I, %r0
643 /* Return to userspace, set no error */
644 b lws_exit
645 copy %r0, %r21
646
6473:
648 /* Error occurred on load or store */
649 /* Free lock */
650 stw %r20, 0(%sr2,%r20)
651#if ENABLE_LWS_DEBUG
652 stw %r0, 4(%sr2,%r20)
653#endif
654 ssm PSW_SM_I, %r0
655 b lws_exit
656 ldo -EFAULT(%r0),%r21 /* set errno */
657 nop
658 nop
659 nop
660 nop
661
662 /* Two exception table entries, one for the load,
663 the other for the store. Either return -EFAULT.
664 Each of the entries must be relocated. */
665 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 3b-linux_gateway_page)
666 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 3b-linux_gateway_page)
667
668
669 /***************************************************
670 New CAS implementation which uses pointers and variable size
671 information. The value pointed by old and new MUST NOT change
672 while performing CAS. The lock only protect the value at %r26.
673
674 %r26 - Address to examine
675 %r25 - Pointer to the value to check (old)
676 %r24 - Pointer to the value to set (new)
677 %r23 - Size of the variable (0/1/2/3 for 8/16/32/64 bit)
678 %r28 - Return non-zero on failure
679 %r21 - Kernel error code
680
681 %r21 has the following meanings:
682
683 EAGAIN - CAS is busy, ldcw failed, try again.
684 EFAULT - Read or write failed.
685
686 Scratch: r20, r22, r28, r29, r1, fr4 (32bit for 64bit CAS only)
687
688 ****************************************************/
689
690 /* ELF32 Process entry path */
691lws_compare_and_swap_2:
692#ifdef CONFIG_64BIT
693 /* Clip the input registers */
694 depdi 0, 31, 32, %r26
695 depdi 0, 31, 32, %r25
696 depdi 0, 31, 32, %r24
697 depdi 0, 31, 32, %r23
698#endif
699
700 /* Check the validity of the size pointer */
701 subi,>>= 4, %r23, %r0
702 b,n lws_exit_nosys
703
704 /* Jump to the functions which will load the old and new values into
705 registers depending on the their size */
706 shlw %r23, 2, %r29
707 blr %r29, %r0
708 nop
709
710 /* 8bit load */
7114: ldb 0(%r25), %r25
712 b cas2_lock_start
7135: ldb 0(%r24), %r24
714 nop
715 nop
716 nop
717 nop
718 nop
719
720 /* 16bit load */
7216: ldh 0(%r25), %r25
722 b cas2_lock_start
7237: ldh 0(%r24), %r24
724 nop
725 nop
726 nop
727 nop
728 nop
729
730 /* 32bit load */
7318: ldw 0(%r25), %r25
732 b cas2_lock_start
7339: ldw 0(%r24), %r24
734 nop
735 nop
736 nop
737 nop
738 nop
739
740 /* 64bit load */
741#ifdef CONFIG_64BIT
74210: ldd 0(%r25), %r25
74311: ldd 0(%r24), %r24
744#else
745 /* Load new value into r22/r23 - high/low */
74610: ldw 0(%r25), %r22
74711: ldw 4(%r25), %r23
748 /* Load new value into fr4 for atomic store later */
74912: flddx 0(%r24), %fr4
750#endif
751
752cas2_lock_start:
753 /* Load start of lock table */
754 ldil L%lws_lock_start, %r20
755 ldo R%lws_lock_start(%r20), %r28
756
757 /* Extract four bits from r26 and hash lock (Bits 4-7) */
758 extru %r26, 27, 4, %r20
759
760 /* Find lock to use, the hash is either one of 0 to
761 15, multiplied by 16 (keep it 16-byte aligned)
762 and add to the lock table offset. */
763 shlw %r20, 4, %r20
764 add %r20, %r28, %r20
765
766 rsm PSW_SM_I, %r0 /* Disable interrupts */
767 /* COW breaks can cause contention on UP systems */
768 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */
769 cmpb,<>,n %r0, %r28, cas2_action /* Did we get it? */
770cas2_wouldblock:
771 ldo 2(%r0), %r28 /* 2nd case */
772 ssm PSW_SM_I, %r0
773 b lws_exit /* Contended... */
774 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */
775
776 /*
777 prev = *addr;
778 if ( prev == old )
779 *addr = new;
780 return prev;
781 */
782
783 /* NOTES:
784 This all works becuse intr_do_signal
785 and schedule both check the return iasq
786 and see that we are on the kernel page
787 so this process is never scheduled off
788 or is ever sent any signal of any sort,
789 thus it is wholly atomic from usrspaces
790 perspective
791 */
792cas2_action:
793 /* Jump to the correct function */
794 blr %r29, %r0
795 /* Set %r28 as non-zero for now */
796 ldo 1(%r0),%r28
797
798 /* 8bit CAS */
79913: ldb,ma 0(%r26), %r29
800 sub,= %r29, %r25, %r0
801 b,n cas2_end
80214: stb,ma %r24, 0(%r26)
803 b cas2_end
804 copy %r0, %r28
805 nop
806 nop
807
808 /* 16bit CAS */
80915: ldh,ma 0(%r26), %r29
810 sub,= %r29, %r25, %r0
811 b,n cas2_end
81216: sth,ma %r24, 0(%r26)
813 b cas2_end
814 copy %r0, %r28
815 nop
816 nop
817
818 /* 32bit CAS */
81917: ldw,ma 0(%r26), %r29
820 sub,= %r29, %r25, %r0
821 b,n cas2_end
82218: stw,ma %r24, 0(%r26)
823 b cas2_end
824 copy %r0, %r28
825 nop
826 nop
827
828 /* 64bit CAS */
829#ifdef CONFIG_64BIT
83019: ldd,ma 0(%r26), %r29
831 sub,*= %r29, %r25, %r0
832 b,n cas2_end
83320: std,ma %r24, 0(%r26)
834 copy %r0, %r28
835#else
836 /* Compare first word */
83719: ldw,ma 0(%r26), %r29
838 sub,= %r29, %r22, %r0
839 b,n cas2_end
840 /* Compare second word */
84120: ldw,ma 4(%r26), %r29
842 sub,= %r29, %r23, %r0
843 b,n cas2_end
844 /* Perform the store */
84521: fstdx %fr4, 0(%r26)
846 copy %r0, %r28
847#endif
848
849cas2_end:
850 /* Free lock */
851 stw,ma %r20, 0(%sr2,%r20)
852 /* Enable interrupts */
853 ssm PSW_SM_I, %r0
854 /* Return to userspace, set no error */
855 b lws_exit
856 copy %r0, %r21
857
85822:
859 /* Error occurred on load or store */
860 /* Free lock */
861 stw %r20, 0(%sr2,%r20)
862 ssm PSW_SM_I, %r0
863 ldo 1(%r0),%r28
864 b lws_exit
865 ldo -EFAULT(%r0),%r21 /* set errno */
866 nop
867 nop
868 nop
869
870 /* Exception table entries, for the load and store, return EFAULT.
871 Each of the entries must be relocated. */
872 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 22b-linux_gateway_page)
873 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 22b-linux_gateway_page)
874 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 22b-linux_gateway_page)
875 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 22b-linux_gateway_page)
876 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 22b-linux_gateway_page)
877 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 22b-linux_gateway_page)
878 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 22b-linux_gateway_page)
879 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 22b-linux_gateway_page)
880 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 22b-linux_gateway_page)
881 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 22b-linux_gateway_page)
882 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 22b-linux_gateway_page)
883 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 22b-linux_gateway_page)
884 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 22b-linux_gateway_page)
885 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 22b-linux_gateway_page)
886 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 22b-linux_gateway_page)
887 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 22b-linux_gateway_page)
888#ifndef CONFIG_64BIT
889 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 22b-linux_gateway_page)
890 ASM_EXCEPTIONTABLE_ENTRY(21b-linux_gateway_page, 22b-linux_gateway_page)
891#endif
892
893 /* Make sure nothing else is placed on this page */
894 .align PAGE_SIZE
895END(linux_gateway_page)
896ENTRY(end_linux_gateway_page)
897
898 /* Relocate symbols assuming linux_gateway_page is mapped
899 to virtual address 0x0 */
900
901#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page)
902
903 .section .rodata,"a"
904
905 .align 8
906 /* Light-weight-syscall table */
907 /* Start of lws table. */
908ENTRY(lws_table)
909 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic 32bit CAS */
910 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic 32bit CAS */
911 LWS_ENTRY(compare_and_swap_2) /* 2 - ELF32 Atomic 64bit CAS */
912END(lws_table)
913 /* End of lws table */
914
915 .align 8
916ENTRY(sys_call_table)
917 .export sys_call_table,data
918#include "syscall_table.S"
919END(sys_call_table)
920
921#ifdef CONFIG_64BIT
922 .align 8
923ENTRY(sys_call_table64)
924#define SYSCALL_TABLE_64BIT
925#include "syscall_table.S"
926END(sys_call_table64)
927#endif
928
929 /*
930 All light-weight-syscall atomic operations
931 will use this set of locks
932
933 NOTE: The lws_lock_start symbol must be
934 at least 16-byte aligned for safe use
935 with ldcw.
936 */
937 .section .data
938 .align L1_CACHE_BYTES
939ENTRY(lws_lock_start)
940 /* lws locks */
941 .rept 16
942 /* Keep locks aligned at 16-bytes */
943 .word 1
944 .word 0
945 .word 0
946 .word 0
947 .endr
948END(lws_lock_start)
949 .previous
950
951.end
952
953