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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> | |
13 | #include <asm/psw.h> | |
14 | #include <asm/thread_info.h> | |
15 | ||
16 | #include <asm/assembly.h> | |
17 | #include <asm/processor.h> | |
18 | ||
19 | /* We fill the empty parts of the gateway page with | |
20 | * something that will kill the kernel or a | |
21 | * userspace application. | |
22 | */ | |
23 | #define KILL_INSN break 0,0 | |
24 | ||
413059f2 | 25 | #ifdef CONFIG_64BIT |
1da177e4 LT |
26 | .level 2.0w |
27 | #else | |
28 | .level 1.1 | |
29 | #endif | |
30 | ||
1da177e4 LT |
31 | .text |
32 | ||
33 | .import syscall_exit,code | |
34 | .import syscall_exit_rfi,code | |
35 | .export linux_gateway_page | |
36 | ||
37 | /* Linux gateway page is aliased to virtual page 0 in the kernel | |
38 | * address space. Since it is a gateway page it cannot be | |
39 | * dereferenced, so null pointers will still fault. We start | |
40 | * the actual entry point at 0x100. We put break instructions | |
41 | * at the beginning of the page to trap null indirect function | |
42 | * pointers. | |
43 | */ | |
44 | ||
2fd83038 | 45 | .align ASM_PAGE_SIZE |
1da177e4 LT |
46 | linux_gateway_page: |
47 | ||
48 | /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ | |
49 | .rept 44 | |
50 | KILL_INSN | |
51 | .endr | |
52 | ||
53 | /* ADDRESS 0xb0 to 0xb4, lws uses 1 insns for entry */ | |
54 | /* Light-weight-syscall entry must always be located at 0xb0 */ | |
55 | /* WARNING: Keep this number updated with table size changes */ | |
56 | #define __NR_lws_entries (2) | |
57 | ||
58 | lws_entry: | |
59 | /* Unconditional branch to lws_start, located on the | |
60 | same gateway page */ | |
61 | b,n lws_start | |
62 | ||
63 | /* Fill from 0xb4 to 0xe0 */ | |
64 | .rept 11 | |
65 | KILL_INSN | |
66 | .endr | |
67 | ||
68 | /* This function MUST be located at 0xe0 for glibc's threading | |
69 | mechanism to work. DO NOT MOVE THIS CODE EVER! */ | |
70 | set_thread_pointer: | |
71 | gate .+8, %r0 /* increase privilege */ | |
72 | depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ | |
73 | be 0(%sr7,%r31) /* return to user space */ | |
74 | mtctl %r26, %cr27 /* move arg0 to the control register */ | |
75 | ||
76 | /* Increase the chance of trapping if random jumps occur to this | |
77 | address, fill from 0xf0 to 0x100 */ | |
78 | .rept 4 | |
79 | KILL_INSN | |
80 | .endr | |
81 | ||
82 | /* This address must remain fixed at 0x100 for glibc's syscalls to work */ | |
83 | .align 256 | |
84 | linux_gateway_entry: | |
85 | gate .+8, %r0 /* become privileged */ | |
86 | mtsp %r0,%sr4 /* get kernel space into sr4 */ | |
87 | mtsp %r0,%sr5 /* get kernel space into sr5 */ | |
88 | mtsp %r0,%sr6 /* get kernel space into sr6 */ | |
89 | mfsp %sr7,%r1 /* save user sr7 */ | |
90 | mtsp %r1,%sr3 /* and store it in sr3 */ | |
91 | ||
413059f2 | 92 | #ifdef CONFIG_64BIT |
1da177e4 LT |
93 | /* for now we can *always* set the W bit on entry to the syscall |
94 | * since we don't support wide userland processes. We could | |
95 | * also save the current SM other than in r0 and restore it on | |
96 | * exit from the syscall, and also use that value to know | |
97 | * whether to do narrow or wide syscalls. -PB | |
98 | */ | |
99 | ssm PSW_SM_W, %r1 | |
100 | extrd,u %r1,PSW_W_BIT,1,%r1 | |
101 | /* sp must be aligned on 4, so deposit the W bit setting into | |
102 | * the bottom of sp temporarily */ | |
103 | or,ev %r1,%r30,%r30 | |
104 | b,n 1f | |
105 | /* The top halves of argument registers must be cleared on syscall | |
106 | * entry from narrow executable. | |
107 | */ | |
108 | depdi 0, 31, 32, %r26 | |
109 | depdi 0, 31, 32, %r25 | |
110 | depdi 0, 31, 32, %r24 | |
111 | depdi 0, 31, 32, %r23 | |
112 | depdi 0, 31, 32, %r22 | |
113 | depdi 0, 31, 32, %r21 | |
114 | 1: | |
115 | #endif | |
116 | mfctl %cr30,%r1 | |
117 | xor %r1,%r30,%r30 /* ye olde xor trick */ | |
118 | xor %r1,%r30,%r1 | |
119 | xor %r1,%r30,%r30 | |
120 | ||
121 | ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ | |
122 | ||
123 | /* N.B.: It is critical that we don't set sr7 to 0 until r30 | |
124 | * contains a valid kernel stack pointer. It is also | |
125 | * critical that we don't start using the kernel stack | |
126 | * until after sr7 has been set to 0. | |
127 | */ | |
128 | ||
129 | mtsp %r0,%sr7 /* get kernel space into sr7 */ | |
130 | STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ | |
131 | mfctl %cr30,%r1 /* get task ptr in %r1 */ | |
132 | LDREG TI_TASK(%r1),%r1 | |
133 | ||
134 | /* Save some registers for sigcontext and potential task | |
135 | switch (see entry.S for the details of which ones are | |
136 | saved/restored). TASK_PT_PSW is zeroed so we can see whether | |
137 | a process is on a syscall or not. For an interrupt the real | |
138 | PSW value is stored. This is needed for gdb and sys_ptrace. */ | |
139 | STREG %r0, TASK_PT_PSW(%r1) | |
140 | STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ | |
141 | STREG %r19, TASK_PT_GR19(%r1) | |
142 | ||
143 | LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ | |
413059f2 | 144 | #ifdef CONFIG_64BIT |
1da177e4 LT |
145 | extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ |
146 | #if 0 | |
147 | xor %r19,%r2,%r2 /* clear bottom bit */ | |
148 | depd,z %r19,1,1,%r19 | |
149 | std %r19,TASK_PT_PSW(%r1) | |
150 | #endif | |
151 | #endif | |
152 | STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ | |
153 | ||
aa0eecb0 | 154 | STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ |
1da177e4 LT |
155 | STREG %r21, TASK_PT_GR21(%r1) |
156 | STREG %r22, TASK_PT_GR22(%r1) | |
157 | STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ | |
158 | STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ | |
159 | STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ | |
160 | STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ | |
161 | STREG %r27, TASK_PT_GR27(%r1) /* user dp */ | |
162 | STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ | |
163 | STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ | |
164 | STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ | |
165 | STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ | |
166 | ||
167 | ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ | |
168 | save_fp %r27 /* or potential task switch */ | |
169 | ||
170 | mfctl %cr11, %r27 /* i.e. SAR */ | |
171 | STREG %r27, TASK_PT_SAR(%r1) | |
172 | ||
173 | loadgp | |
174 | ||
413059f2 | 175 | #ifdef CONFIG_64BIT |
1da177e4 LT |
176 | ldo -16(%r30),%r29 /* Reference param save area */ |
177 | copy %r19,%r2 /* W bit back to r2 */ | |
178 | #else | |
179 | /* no need to save these on stack in wide mode because the first 8 | |
180 | * args are passed in registers */ | |
181 | stw %r22, -52(%r30) /* 5th argument */ | |
182 | stw %r21, -56(%r30) /* 6th argument */ | |
183 | #endif | |
184 | ||
185 | /* Are we being ptraced? */ | |
186 | mfctl %cr30, %r1 | |
187 | LDREG TI_TASK(%r1),%r1 | |
188 | LDREG TASK_PTRACE(%r1), %r1 | |
189 | bb,<,n %r1,31,.Ltracesys | |
190 | ||
191 | /* Note! We cannot use the syscall table that is mapped | |
192 | nearby since the gateway page is mapped execute-only. */ | |
193 | ||
413059f2 | 194 | #ifdef CONFIG_64BIT |
1da177e4 LT |
195 | ldil L%sys_call_table, %r1 |
196 | or,= %r2,%r2,%r2 | |
197 | addil L%(sys_call_table64-sys_call_table), %r1 | |
198 | ldo R%sys_call_table(%r1), %r19 | |
199 | or,= %r2,%r2,%r2 | |
200 | ldo R%sys_call_table64(%r1), %r19 | |
201 | #else | |
202 | ldil L%sys_call_table, %r1 | |
203 | ldo R%sys_call_table(%r1), %r19 | |
204 | #endif | |
205 | comiclr,>>= __NR_Linux_syscalls, %r20, %r0 | |
206 | b,n .Lsyscall_nosys | |
207 | ||
208 | LDREGX %r20(%r19), %r19 | |
209 | ||
210 | /* If this is a sys_rt_sigreturn call, and the signal was received | |
211 | * when not in_syscall, then we want to return via syscall_exit_rfi, | |
212 | * not syscall_exit. Signal no. in r20, in_syscall in r25 (see | |
213 | * trampoline code in signal.c). | |
214 | */ | |
215 | ldi __NR_rt_sigreturn,%r2 | |
216 | comb,= %r2,%r20,.Lrt_sigreturn | |
217 | .Lin_syscall: | |
218 | ldil L%syscall_exit,%r2 | |
219 | be 0(%sr7,%r19) | |
220 | ldo R%syscall_exit(%r2),%r2 | |
221 | .Lrt_sigreturn: | |
222 | comib,<> 0,%r25,.Lin_syscall | |
223 | ldil L%syscall_exit_rfi,%r2 | |
224 | be 0(%sr7,%r19) | |
225 | ldo R%syscall_exit_rfi(%r2),%r2 | |
226 | ||
227 | /* Note! Because we are not running where we were linked, any | |
228 | calls to functions external to this file must be indirect. To | |
229 | be safe, we apply the opposite rule to functions within this | |
230 | file, with local labels given to them to ensure correctness. */ | |
231 | ||
232 | .Lsyscall_nosys: | |
233 | syscall_nosys: | |
234 | ldil L%syscall_exit,%r1 | |
235 | be R%syscall_exit(%sr7,%r1) | |
236 | ldo -ENOSYS(%r0),%r28 /* set errno */ | |
237 | ||
238 | ||
239 | /* Warning! This trace code is a virtual duplicate of the code above so be | |
240 | * sure to maintain both! */ | |
241 | .Ltracesys: | |
242 | tracesys: | |
243 | /* Need to save more registers so the debugger can see where we | |
244 | * are. This saves only the lower 8 bits of PSW, so that the C | |
245 | * bit is still clear on syscalls, and the D bit is set if this | |
246 | * full register save path has been executed. We check the D | |
247 | * bit on syscall_return_rfi to determine which registers to | |
248 | * restore. An interrupt results in a full PSW saved with the | |
249 | * C bit set, a non-straced syscall entry results in C and D clear | |
250 | * in the saved PSW. | |
251 | */ | |
252 | ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ | |
253 | LDREG TI_TASK(%r1), %r1 | |
254 | ssm 0,%r2 | |
255 | STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ | |
256 | mfsp %sr0,%r2 | |
257 | STREG %r2,TASK_PT_SR0(%r1) | |
258 | mfsp %sr1,%r2 | |
259 | STREG %r2,TASK_PT_SR1(%r1) | |
260 | mfsp %sr2,%r2 | |
261 | STREG %r2,TASK_PT_SR2(%r1) | |
262 | mfsp %sr3,%r2 | |
263 | STREG %r2,TASK_PT_SR3(%r1) | |
264 | STREG %r2,TASK_PT_SR4(%r1) | |
265 | STREG %r2,TASK_PT_SR5(%r1) | |
266 | STREG %r2,TASK_PT_SR6(%r1) | |
267 | STREG %r2,TASK_PT_SR7(%r1) | |
268 | STREG %r2,TASK_PT_IASQ0(%r1) | |
269 | STREG %r2,TASK_PT_IASQ1(%r1) | |
270 | LDREG TASK_PT_GR31(%r1),%r2 | |
271 | STREG %r2,TASK_PT_IAOQ0(%r1) | |
272 | ldo 4(%r2),%r2 | |
273 | STREG %r2,TASK_PT_IAOQ1(%r1) | |
274 | ldo TASK_REGS(%r1),%r2 | |
275 | /* reg_save %r2 */ | |
276 | STREG %r3,PT_GR3(%r2) | |
277 | STREG %r4,PT_GR4(%r2) | |
278 | STREG %r5,PT_GR5(%r2) | |
279 | STREG %r6,PT_GR6(%r2) | |
280 | STREG %r7,PT_GR7(%r2) | |
281 | STREG %r8,PT_GR8(%r2) | |
282 | STREG %r9,PT_GR9(%r2) | |
283 | STREG %r10,PT_GR10(%r2) | |
284 | STREG %r11,PT_GR11(%r2) | |
285 | STREG %r12,PT_GR12(%r2) | |
286 | STREG %r13,PT_GR13(%r2) | |
287 | STREG %r14,PT_GR14(%r2) | |
288 | STREG %r15,PT_GR15(%r2) | |
289 | STREG %r16,PT_GR16(%r2) | |
290 | STREG %r17,PT_GR17(%r2) | |
291 | STREG %r18,PT_GR18(%r2) | |
292 | /* Finished saving things for the debugger */ | |
293 | ||
294 | ldil L%syscall_trace,%r1 | |
295 | ldil L%tracesys_next,%r2 | |
296 | be R%syscall_trace(%sr7,%r1) | |
297 | ldo R%tracesys_next(%r2),%r2 | |
298 | ||
299 | tracesys_next: | |
300 | ldil L%sys_call_table,%r1 | |
301 | ldo R%sys_call_table(%r1), %r19 | |
302 | ||
303 | ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ | |
304 | LDREG TI_TASK(%r1), %r1 | |
305 | LDREG TASK_PT_GR20(%r1), %r20 | |
306 | LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ | |
307 | LDREG TASK_PT_GR25(%r1), %r25 | |
308 | LDREG TASK_PT_GR24(%r1), %r24 | |
309 | LDREG TASK_PT_GR23(%r1), %r23 | |
413059f2 | 310 | #ifdef CONFIG_64BIT |
1da177e4 LT |
311 | LDREG TASK_PT_GR22(%r1), %r22 |
312 | LDREG TASK_PT_GR21(%r1), %r21 | |
313 | ldo -16(%r30),%r29 /* Reference param save area */ | |
314 | #endif | |
315 | ||
316 | comiclr,>>= __NR_Linux_syscalls, %r20, %r0 | |
317 | b,n .Lsyscall_nosys | |
318 | ||
319 | LDREGX %r20(%r19), %r19 | |
320 | ||
321 | /* If this is a sys_rt_sigreturn call, and the signal was received | |
322 | * when not in_syscall, then we want to return via syscall_exit_rfi, | |
323 | * not syscall_exit. Signal no. in r20, in_syscall in r25 (see | |
324 | * trampoline code in signal.c). | |
325 | */ | |
326 | ldi __NR_rt_sigreturn,%r2 | |
327 | comb,= %r2,%r20,.Ltrace_rt_sigreturn | |
328 | .Ltrace_in_syscall: | |
329 | ldil L%tracesys_exit,%r2 | |
330 | be 0(%sr7,%r19) | |
331 | ldo R%tracesys_exit(%r2),%r2 | |
332 | ||
333 | /* Do *not* call this function on the gateway page, because it | |
334 | makes a direct call to syscall_trace. */ | |
335 | ||
336 | tracesys_exit: | |
337 | ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ | |
338 | LDREG TI_TASK(%r1), %r1 | |
413059f2 | 339 | #ifdef CONFIG_64BIT |
1da177e4 LT |
340 | ldo -16(%r30),%r29 /* Reference param save area */ |
341 | #endif | |
342 | bl syscall_trace, %r2 | |
343 | STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ | |
344 | ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ | |
345 | LDREG TI_TASK(%r1), %r1 | |
346 | LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ | |
347 | ||
348 | ldil L%syscall_exit,%r1 | |
349 | be,n R%syscall_exit(%sr7,%r1) | |
350 | ||
351 | .Ltrace_rt_sigreturn: | |
352 | comib,<> 0,%r25,.Ltrace_in_syscall | |
353 | ldil L%tracesys_sigexit,%r2 | |
354 | be 0(%sr7,%r19) | |
355 | ldo R%tracesys_sigexit(%r2),%r2 | |
356 | ||
357 | tracesys_sigexit: | |
358 | ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ | |
359 | LDREG 0(%r1), %r1 | |
413059f2 | 360 | #ifdef CONFIG_64BIT |
1da177e4 LT |
361 | ldo -16(%r30),%r29 /* Reference param save area */ |
362 | #endif | |
363 | bl syscall_trace, %r2 | |
364 | nop | |
365 | ||
366 | ldil L%syscall_exit_rfi,%r1 | |
367 | be,n R%syscall_exit_rfi(%sr7,%r1) | |
368 | ||
369 | ||
370 | /********************************************************* | |
371 | Light-weight-syscall code | |
372 | ||
373 | r20 - lws number | |
374 | r26,r25,r24,r23,r22 - Input registers | |
375 | r28 - Function return register | |
376 | r21 - Error code. | |
377 | ||
378 | Scracth: Any of the above that aren't being | |
379 | currently used, including r1. | |
380 | ||
381 | Return pointer: r31 (Not usable) | |
382 | ||
383 | Error codes returned by entry path: | |
384 | ||
385 | ENOSYS - r20 was an invalid LWS number. | |
386 | ||
387 | *********************************************************/ | |
388 | lws_start: | |
389 | /* Gate and ensure we return to userspace */ | |
390 | gate .+8, %r0 | |
391 | depi 3, 31, 2, %r31 /* Ensure we return to userspace */ | |
392 | ||
413059f2 | 393 | #ifdef CONFIG_64BIT |
1da177e4 LT |
394 | /* FIXME: If we are a 64-bit kernel just |
395 | * turn this on unconditionally. | |
396 | */ | |
397 | ssm PSW_SM_W, %r1 | |
398 | extrd,u %r1,PSW_W_BIT,1,%r1 | |
399 | /* sp must be aligned on 4, so deposit the W bit setting into | |
400 | * the bottom of sp temporarily */ | |
401 | or,ev %r1,%r30,%r30 | |
402 | ||
403 | /* Clip LWS number to a 32-bit value always */ | |
404 | depdi 0, 31, 32, %r20 | |
405 | #endif | |
406 | ||
407 | /* Is the lws entry number valid? */ | |
408 | comiclr,>>= __NR_lws_entries, %r20, %r0 | |
409 | b,n lws_exit_nosys | |
410 | ||
411 | /* WARNING: Trashing sr2 and sr3 */ | |
412 | mfsp %sr7,%r1 /* get userspace into sr3 */ | |
413 | mtsp %r1,%sr3 | |
414 | mtsp %r0,%sr2 /* get kernel space into sr2 */ | |
415 | ||
416 | /* Load table start */ | |
417 | ldil L%lws_table, %r1 | |
418 | ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ | |
419 | LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ | |
420 | ||
421 | /* Jump to lws, lws table pointers already relocated */ | |
422 | be,n 0(%sr2,%r21) | |
423 | ||
424 | lws_exit_nosys: | |
425 | ldo -ENOSYS(%r0),%r21 /* set errno */ | |
426 | /* Fall through: Return to userspace */ | |
427 | ||
428 | lws_exit: | |
413059f2 | 429 | #ifdef CONFIG_64BIT |
1da177e4 LT |
430 | /* decide whether to reset the wide mode bit |
431 | * | |
432 | * For a syscall, the W bit is stored in the lowest bit | |
433 | * of sp. Extract it and reset W if it is zero */ | |
434 | extrd,u,*<> %r30,63,1,%r1 | |
435 | rsm PSW_SM_W, %r0 | |
436 | /* now reset the lowest bit of sp if it was set */ | |
437 | xor %r30,%r1,%r30 | |
438 | #endif | |
439 | be,n 0(%sr3, %r31) | |
440 | ||
441 | ||
442 | ||
443 | /*************************************************** | |
444 | Implementing CAS as an atomic operation: | |
445 | ||
446 | %r26 - Address to examine | |
447 | %r25 - Old value to check (old) | |
448 | %r24 - New value to set (new) | |
449 | %r28 - Return prev through this register. | |
450 | %r21 - Kernel error code | |
451 | ||
452 | If debugging is DISabled: | |
453 | ||
454 | %r21 has the following meanings: | |
455 | ||
456 | EAGAIN - CAS is busy, ldcw failed, try again. | |
457 | EFAULT - Read or write failed. | |
458 | ||
459 | If debugging is enabled: | |
460 | ||
461 | EDEADLOCK - CAS called recursively. | |
462 | EAGAIN && r28 == 1 - CAS is busy. Lock contended. | |
463 | EAGAIN && r28 == 2 - CAS is busy. ldcw failed. | |
464 | EFAULT - Read or write failed. | |
465 | ||
466 | Scratch: r20, r28, r1 | |
467 | ||
468 | ****************************************************/ | |
469 | ||
470 | /* Do not enable LWS debugging */ | |
471 | #define ENABLE_LWS_DEBUG 0 | |
472 | ||
473 | /* ELF64 Process entry path */ | |
474 | lws_compare_and_swap64: | |
413059f2 | 475 | #ifdef CONFIG_64BIT |
1da177e4 LT |
476 | b,n lws_compare_and_swap |
477 | #else | |
478 | /* If we are not a 64-bit kernel, then we don't | |
479 | * implement having 64-bit input registers | |
480 | */ | |
481 | b,n lws_exit_nosys | |
482 | #endif | |
483 | ||
484 | /* ELF32 Process entry path */ | |
485 | lws_compare_and_swap32: | |
413059f2 | 486 | #ifdef CONFIG_64BIT |
1da177e4 LT |
487 | /* Clip all the input registers */ |
488 | depdi 0, 31, 32, %r26 | |
489 | depdi 0, 31, 32, %r25 | |
490 | depdi 0, 31, 32, %r24 | |
491 | #endif | |
492 | ||
493 | lws_compare_and_swap: | |
494 | #ifdef CONFIG_SMP | |
495 | /* Load start of lock table */ | |
496 | ldil L%lws_lock_start, %r20 | |
497 | ldo R%lws_lock_start(%r20), %r28 | |
498 | ||
499 | /* Extract four bits from r26 and hash lock (Bits 4-7) */ | |
500 | extru %r26, 27, 4, %r20 | |
501 | ||
502 | /* Find lock to use, the hash is either one of 0 to | |
503 | 15, multiplied by 16 (keep it 16-byte aligned) | |
504 | and add to the lock table offset. */ | |
505 | shlw %r20, 4, %r20 | |
506 | add %r20, %r28, %r20 | |
507 | ||
508 | # ifdef ENABLE_LWS_DEBUG | |
509 | /* | |
510 | DEBUG, check for deadlock! | |
511 | If the thread register values are the same | |
512 | then we were the one that locked it last and | |
513 | this is a recurisve call that will deadlock. | |
514 | We *must* giveup this call and fail. | |
515 | */ | |
516 | ldw 4(%sr2,%r20), %r28 /* Load thread register */ | |
aa0eecb0 | 517 | /* WARNING: If cr27 cycles to the same value we have problems */ |
1da177e4 LT |
518 | mfctl %cr27, %r21 /* Get current thread register */ |
519 | cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ | |
520 | b lws_exit /* Return error! */ | |
521 | ldo -EDEADLOCK(%r0), %r21 | |
522 | cas_lock: | |
523 | cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ | |
524 | ldo 1(%r0), %r28 /* 1st case */ | |
525 | b lws_exit /* Contended... */ | |
526 | ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ | |
527 | cas_nocontend: | |
528 | # endif | |
529 | /* ENABLE_LWS_DEBUG */ | |
530 | ||
64f49532 | 531 | LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ |
1da177e4 LT |
532 | cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ |
533 | cas_wouldblock: | |
534 | ldo 2(%r0), %r28 /* 2nd case */ | |
535 | b lws_exit /* Contended... */ | |
536 | ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ | |
537 | #endif | |
538 | /* CONFIG_SMP */ | |
539 | ||
540 | /* | |
541 | prev = *addr; | |
542 | if ( prev == old ) | |
543 | *addr = new; | |
544 | return prev; | |
545 | */ | |
546 | ||
547 | /* NOTES: | |
548 | This all works becuse intr_do_signal | |
549 | and schedule both check the return iasq | |
550 | and see that we are on the kernel page | |
551 | so this process is never scheduled off | |
552 | or is ever sent any signal of any sort, | |
553 | thus it is wholly atomic from usrspaces | |
554 | perspective | |
555 | */ | |
556 | cas_action: | |
557 | #if defined CONFIG_SMP && defined ENABLE_LWS_DEBUG | |
558 | /* DEBUG */ | |
559 | mfctl %cr27, %r1 | |
560 | stw %r1, 4(%sr2,%r20) | |
561 | #endif | |
562 | /* The load and store could fail */ | |
563 | 1: ldw 0(%sr3,%r26), %r28 | |
564 | sub,<> %r28, %r25, %r0 | |
565 | 2: stw %r24, 0(%sr3,%r26) | |
566 | #ifdef CONFIG_SMP | |
567 | /* Free lock */ | |
568 | stw %r20, 0(%sr2,%r20) | |
569 | # ifdef ENABLE_LWS_DEBUG | |
570 | /* Clear thread register indicator */ | |
571 | stw %r0, 4(%sr2,%r20) | |
572 | # endif | |
573 | #endif | |
574 | /* Return to userspace, set no error */ | |
575 | b lws_exit | |
576 | copy %r0, %r21 | |
577 | ||
578 | 3: | |
579 | /* Error occured on load or store */ | |
580 | #ifdef CONFIG_SMP | |
581 | /* Free lock */ | |
582 | stw %r20, 0(%sr2,%r20) | |
583 | # ifdef ENABLE_LWS_DEBUG | |
584 | stw %r0, 4(%sr2,%r20) | |
585 | # endif | |
586 | #endif | |
587 | b lws_exit | |
588 | ldo -EFAULT(%r0),%r21 /* set errno */ | |
589 | nop | |
590 | nop | |
591 | nop | |
592 | nop | |
593 | ||
594 | /* Two exception table entries, one for the load, | |
595 | the other for the store. Either return -EFAULT. | |
596 | Each of the entries must be relocated. */ | |
597 | .section __ex_table,"aw" | |
413059f2 | 598 | #ifdef CONFIG_64BIT |
1da177e4 LT |
599 | /* Pad the address calculation */ |
600 | .word 0,(2b - linux_gateway_page) | |
601 | .word 0,(3b - linux_gateway_page) | |
602 | #else | |
603 | .word (2b - linux_gateway_page) | |
604 | .word (3b - linux_gateway_page) | |
605 | #endif | |
606 | .previous | |
607 | ||
608 | .section __ex_table,"aw" | |
413059f2 | 609 | #ifdef CONFIG_64BIT |
1da177e4 LT |
610 | /* Pad the address calculation */ |
611 | .word 0,(1b - linux_gateway_page) | |
612 | .word 0,(3b - linux_gateway_page) | |
613 | #else | |
614 | .word (1b - linux_gateway_page) | |
615 | .word (3b - linux_gateway_page) | |
616 | #endif | |
617 | .previous | |
618 | ||
619 | end_compare_and_swap: | |
620 | ||
621 | /* Make sure nothing else is placed on this page */ | |
2fd83038 | 622 | .align ASM_PAGE_SIZE |
1da177e4 LT |
623 | .export end_linux_gateway_page |
624 | end_linux_gateway_page: | |
625 | ||
626 | /* Relocate symbols assuming linux_gateway_page is mapped | |
627 | to virtual address 0x0 */ | |
413059f2 | 628 | #ifdef CONFIG_64BIT |
1da177e4 LT |
629 | /* FIXME: The code will always be on the gateay page |
630 | and thus it will be on the first 4k, the | |
631 | assembler seems to think that the final | |
632 | subtraction result is only a word in | |
633 | length, so we pad the value. | |
634 | */ | |
635 | #define LWS_ENTRY(_name_) .word 0,(lws_##_name_ - linux_gateway_page) | |
636 | #else | |
637 | #define LWS_ENTRY(_name_) .word (lws_##_name_ - linux_gateway_page) | |
638 | #endif | |
639 | ||
1bcdd854 HD |
640 | .section .rodata,"a" |
641 | ||
2fd83038 | 642 | .align ASM_PAGE_SIZE |
1da177e4 LT |
643 | /* Light-weight-syscall table */ |
644 | /* Start of lws table. */ | |
645 | .export lws_table | |
646 | .Llws_table: | |
647 | lws_table: | |
648 | LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ | |
649 | LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ | |
650 | /* End of lws table */ | |
651 | ||
2fd83038 | 652 | .align ASM_PAGE_SIZE |
1da177e4 LT |
653 | .export sys_call_table |
654 | .Lsys_call_table: | |
655 | sys_call_table: | |
656 | #include "syscall_table.S" | |
657 | ||
413059f2 | 658 | #ifdef CONFIG_64BIT |
2fd83038 | 659 | .align ASM_PAGE_SIZE |
1da177e4 LT |
660 | .export sys_call_table64 |
661 | .Lsys_call_table64: | |
662 | sys_call_table64: | |
663 | #define SYSCALL_TABLE_64BIT | |
664 | #include "syscall_table.S" | |
665 | #endif | |
666 | ||
667 | #ifdef CONFIG_SMP | |
668 | /* | |
669 | All light-weight-syscall atomic operations | |
670 | will use this set of locks | |
671 | */ | |
672 | .section .data | |
673 | .align 4096 | |
674 | .export lws_lock_start | |
675 | .Llws_lock_start: | |
676 | lws_lock_start: | |
677 | /* lws locks */ | |
678 | .align 16 | |
679 | .rept 16 | |
680 | /* Keep locks aligned at 16-bytes */ | |
681 | .word 1 | |
682 | .word 0 | |
683 | .word 0 | |
684 | .word 0 | |
685 | .endr | |
686 | .previous | |
687 | #endif | |
688 | /* CONFIG_SMP for lws_lock_start */ | |
689 | ||
690 | .end | |
691 | ||
692 |