1/* 2 * Linux/PA-RISC Project (http://www.parisc-linux.org/) 3 * 4 * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai> 5 * Licensed under the GNU GPL. 6 * thanks to Philipp Rumpf, Mike Shaver and various others 7 * sorry about the wall, puffin.. 8 */ 9 10#include <asm/asm-offsets.h> 11#include <asm/unistd.h> 12#include <asm/errno.h> 13#include <asm/page.h> 14#include <asm/psw.h> 15#include <asm/thread_info.h> 16#include <asm/assembly.h> 17#include <asm/processor.h> 18 19#include <linux/linkage.h> 20 21 /* We fill the empty parts of the gateway page with 22 * something that will kill the kernel or a 23 * userspace application. 24 */ 25#define KILL_INSN break 0,0 26 27 .level LEVEL 28 29 .text 30 31 .import syscall_exit,code 32 .import syscall_exit_rfi,code 33 34 /* Linux gateway page is aliased to virtual page 0 in the kernel 35 * address space. Since it is a gateway page it cannot be 36 * dereferenced, so null pointers will still fault. We start 37 * the actual entry point at 0x100. We put break instructions 38 * at the beginning of the page to trap null indirect function 39 * pointers. 40 */ 41 42 .align PAGE_SIZE 43ENTRY(linux_gateway_page) 44 45 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 46 .rept 44 47 KILL_INSN 48 .endr 49 50 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */ 51 /* Light-weight-syscall entry must always be located at 0xb0 */ 52 /* WARNING: Keep this number updated with table size changes */ 53#define __NR_lws_entries (2) 54 55lws_entry: 56 gate lws_start, %r0 /* increase privilege */ 57 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 58 59 /* Fill from 0xb8 to 0xe0 */ 60 .rept 10 61 KILL_INSN 62 .endr 63 64 /* This function MUST be located at 0xe0 for glibc's threading 65 mechanism to work. DO NOT MOVE THIS CODE EVER! */ 66set_thread_pointer: 67 gate .+8, %r0 /* increase privilege */ 68 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 69 be 0(%sr7,%r31) /* return to user space */ 70 mtctl %r26, %cr27 /* move arg0 to the control register */ 71 72 /* Increase the chance of trapping if random jumps occur to this 73 address, fill from 0xf0 to 0x100 */ 74 .rept 4 75 KILL_INSN 76 .endr 77 78/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 79 .align 256 80linux_gateway_entry: 81 gate .+8, %r0 /* become privileged */ 82 mtsp %r0,%sr4 /* get kernel space into sr4 */ 83 mtsp %r0,%sr5 /* get kernel space into sr5 */ 84 mtsp %r0,%sr6 /* get kernel space into sr6 */ 85 mfsp %sr7,%r1 /* save user sr7 */ 86 mtsp %r1,%sr3 /* and store it in sr3 */ 87 88#ifdef CONFIG_64BIT 89 /* for now we can *always* set the W bit on entry to the syscall 90 * since we don't support wide userland processes. We could 91 * also save the current SM other than in r0 and restore it on 92 * exit from the syscall, and also use that value to know 93 * whether to do narrow or wide syscalls. -PB 94 */ 95 ssm PSW_SM_W, %r1 96 extrd,u %r1,PSW_W_BIT,1,%r1 97 /* sp must be aligned on 4, so deposit the W bit setting into 98 * the bottom of sp temporarily */ 99 or,ev %r1,%r30,%r30 100 b,n 1f 101 /* The top halves of argument registers must be cleared on syscall 102 * entry from narrow executable. 103 */ 104 depdi 0, 31, 32, %r26 105 depdi 0, 31, 32, %r25 106 depdi 0, 31, 32, %r24 107 depdi 0, 31, 32, %r23 108 depdi 0, 31, 32, %r22 109 depdi 0, 31, 32, %r21 1101: 111#endif 112 mfctl %cr30,%r1 113 xor %r1,%r30,%r30 /* ye olde xor trick */ 114 xor %r1,%r30,%r1 115 xor %r1,%r30,%r30 116 117 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 118 119 /* N.B.: It is critical that we don't set sr7 to 0 until r30 120 * contains a valid kernel stack pointer. It is also 121 * critical that we don't start using the kernel stack 122 * until after sr7 has been set to 0. 123 */ 124 125 mtsp %r0,%sr7 /* get kernel space into sr7 */ 126 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 127 mfctl %cr30,%r1 /* get task ptr in %r1 */ 128 LDREG TI_TASK(%r1),%r1 129 130 /* Save some registers for sigcontext and potential task 131 switch (see entry.S for the details of which ones are 132 saved/restored). TASK_PT_PSW is zeroed so we can see whether 133 a process is on a syscall or not. For an interrupt the real 134 PSW value is stored. This is needed for gdb and sys_ptrace. */ 135 STREG %r0, TASK_PT_PSW(%r1) 136 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 137 STREG %r19, TASK_PT_GR19(%r1) 138 139 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 140#ifdef CONFIG_64BIT 141 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 142#if 0 143 xor %r19,%r2,%r2 /* clear bottom bit */ 144 depd,z %r19,1,1,%r19 145 std %r19,TASK_PT_PSW(%r1) 146#endif 147#endif 148 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 149 150 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 151 STREG %r21, TASK_PT_GR21(%r1) 152 STREG %r22, TASK_PT_GR22(%r1) 153 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 154 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 155 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 156 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 157 STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 158 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 159 STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */ 160 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 161 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 162 163 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 164 save_fp %r27 /* or potential task switch */ 165 166 mfctl %cr11, %r27 /* i.e. SAR */ 167 STREG %r27, TASK_PT_SAR(%r1) 168 169 loadgp 170 171#ifdef CONFIG_64BIT 172 ldo -16(%r30),%r29 /* Reference param save area */ 173 copy %r19,%r2 /* W bit back to r2 */ 174#else 175 /* no need to save these on stack in wide mode because the first 8 176 * args are passed in registers */ 177 stw %r22, -52(%r30) /* 5th argument */ 178 stw %r21, -56(%r30) /* 6th argument */ 179#endif 180 181 /* Are we being ptraced? */ 182 mfctl %cr30, %r1 183 LDREG TI_FLAGS(%r1),%r1 184 ldi _TIF_SYSCALL_TRACE_MASK, %r19 185 and,COND(=) %r1, %r19, %r0 186 b,n .Ltracesys 187 188 /* Note! We cannot use the syscall table that is mapped 189 nearby since the gateway page is mapped execute-only. */ 190 191#ifdef CONFIG_64BIT 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 202 comiclr,>> __NR_Linux_syscalls, %r20, %r0 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 */ 290 291 copy %r2,%r26 292 ldil L%do_syscall_trace_enter,%r1 293 ldil L%tracesys_next,%r2 294 be R%do_syscall_trace_enter(%sr7,%r1) 295 ldo R%tracesys_next(%r2),%r2 296 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 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 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 312 LDREG TASK_PT_GR22(%r1), %r22 313 LDREG TASK_PT_GR21(%r1), %r21 314#ifdef CONFIG_64BIT 315 ldo -16(%r30),%r29 /* Reference param save area */ 316#else 317 stw %r22, -52(%r30) /* 5th argument */ 318 stw %r21, -56(%r30) /* 6th argument */ 319#endif 320 321 comiclr,>>= __NR_Linux_syscalls, %r20, %r0 322 b,n .Lsyscall_nosys 323 324 LDREGX %r20(%r19), %r19 325 326 /* If this is a sys_rt_sigreturn call, and the signal was received 327 * when not in_syscall, then we want to return via syscall_exit_rfi, 328 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 329 * trampoline code in signal.c). 330 */ 331 ldi __NR_rt_sigreturn,%r2 332 comb,= %r2,%r20,.Ltrace_rt_sigreturn 333.Ltrace_in_syscall: 334 ldil L%tracesys_exit,%r2 335 be 0(%sr7,%r19) 336 ldo R%tracesys_exit(%r2),%r2 337 338 /* Do *not* call this function on the gateway page, because it 339 makes a direct call to syscall_trace. */ 340 341tracesys_exit: 342 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 343 LDREG TI_TASK(%r1), %r1 344#ifdef CONFIG_64BIT 345 ldo -16(%r30),%r29 /* Reference param save area */ 346#endif 347 ldo TASK_REGS(%r1),%r26 348 bl do_syscall_trace_exit,%r2 349 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 350 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 351 LDREG TI_TASK(%r1), %r1 352 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 353 354 ldil L%syscall_exit,%r1 355 be,n R%syscall_exit(%sr7,%r1) 356 357.Ltrace_rt_sigreturn: 358 comib,<> 0,%r25,.Ltrace_in_syscall 359 ldil L%tracesys_sigexit,%r2 360 be 0(%sr7,%r19) 361 ldo R%tracesys_sigexit(%r2),%r2 362 363tracesys_sigexit: 364 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 365 LDREG TI_TASK(%r1), %r1 366#ifdef CONFIG_64BIT 367 ldo -16(%r30),%r29 /* Reference param save area */ 368#endif 369 bl do_syscall_trace_exit,%r2 370 ldo TASK_REGS(%r1),%r26 371 372 ldil L%syscall_exit_rfi,%r1 373 be,n R%syscall_exit_rfi(%sr7,%r1) 374 375 376 /********************************************************* 377 32/64-bit Light-Weight-Syscall ABI 378 379 * - Indicates a hint for userspace inline asm 380 implementations. 381 382 Syscall number (caller-saves) 383 - %r20 384 * In asm clobber. 385 386 Argument registers (caller-saves) 387 - %r26, %r25, %r24, %r23, %r22 388 * In asm input. 389 390 Return registers (caller-saves) 391 - %r28 (return), %r21 (errno) 392 * In asm output. 393 394 Caller-saves registers 395 - %r1, %r27, %r29 396 - %r2 (return pointer) 397 - %r31 (ble link register) 398 * In asm clobber. 399 400 Callee-saves registers 401 - %r3-%r18 402 - %r30 (stack pointer) 403 * Not in asm clobber. 404 405 If userspace is 32-bit: 406 Callee-saves registers 407 - %r19 (32-bit PIC register) 408 409 Differences from 32-bit calling convention: 410 - Syscall number in %r20 411 - Additional argument register %r22 (arg4) 412 - Callee-saves %r19. 413 414 If userspace is 64-bit: 415 Callee-saves registers 416 - %r27 (64-bit PIC register) 417 418 Differences from 64-bit calling convention: 419 - Syscall number in %r20 420 - Additional argument register %r22 (arg4) 421 - Callee-saves %r27. 422 423 Error codes returned by entry path: 424 425 ENOSYS - r20 was an invalid LWS number. 426 427 *********************************************************/ 428lws_start: 429 430#ifdef CONFIG_64BIT 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: 466#ifdef CONFIG_64BIT 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(%sr7, %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: 512#ifdef CONFIG_64BIT 513 b,n lws_compare_and_swap 514#else 515 /* If we are not a 64-bit kernel, then we don't 516 * have 64-bit input registers, and calling 517 * the 64-bit LWS CAS returns ENOSYS. 518 */ 519 b,n lws_exit_nosys 520#endif 521 522 /* ELF32 Process entry path */ 523lws_compare_and_swap32: 524#ifdef CONFIG_64BIT 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 /* Load start of lock table */ 533 ldil L%lws_lock_start, %r20 534 ldo R%lws_lock_start(%r20), %r28 535 536 /* Extract four bits from r26 and hash lock (Bits 4-7) */ 537 extru %r26, 27, 4, %r20 538 539 /* Find lock to use, the hash is either one of 0 to 540 15, multiplied by 16 (keep it 16-byte aligned) 541 and add to the lock table offset. */ 542 shlw %r20, 4, %r20 543 add %r20, %r28, %r20 544 545# if ENABLE_LWS_DEBUG 546 /* 547 DEBUG, check for deadlock! 548 If the thread register values are the same 549 then we were the one that locked it last and 550 this is a recurisve call that will deadlock. 551 We *must* giveup this call and fail. 552 */ 553 ldw 4(%sr2,%r20), %r28 /* Load thread register */ 554 /* WARNING: If cr27 cycles to the same value we have problems */ 555 mfctl %cr27, %r21 /* Get current thread register */ 556 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 557 b lws_exit /* Return error! */ 558 ldo -EDEADLOCK(%r0), %r21 559cas_lock: 560 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 561 ldo 1(%r0), %r28 /* 1st case */ 562 b lws_exit /* Contended... */ 563 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 564cas_nocontend: 565# endif 566/* ENABLE_LWS_DEBUG */ 567 568 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 569 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 570cas_wouldblock: 571 ldo 2(%r0), %r28 /* 2nd case */ 572 b lws_exit /* Contended... */ 573 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 574 575 /* 576 prev = *addr; 577 if ( prev == old ) 578 *addr = new; 579 return prev; 580 */ 581 582 /* NOTES: 583 This all works becuse intr_do_signal 584 and schedule both check the return iasq 585 and see that we are on the kernel page 586 so this process is never scheduled off 587 or is ever sent any signal of any sort, 588 thus it is wholly atomic from usrspaces 589 perspective 590 */ 591cas_action: 592#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 593 /* DEBUG */ 594 mfctl %cr27, %r1 595 stw %r1, 4(%sr2,%r20) 596#endif 597 /* The load and store could fail */ 5981: ldw 0(%sr3,%r26), %r28 599 sub,<> %r28, %r25, %r0 6002: stw %r24, 0(%sr3,%r26) 601 /* Free lock */ 602 stw %r20, 0(%sr2,%r20) 603#if ENABLE_LWS_DEBUG 604 /* Clear thread register indicator */ 605 stw %r0, 4(%sr2,%r20) 606#endif 607 /* Return to userspace, set no error */ 608 b lws_exit 609 copy %r0, %r21 610 6113: 612 /* Error occurred on load or store */ 613 /* Free lock */ 614 stw %r20, 0(%sr2,%r20) 615#if ENABLE_LWS_DEBUG 616 stw %r0, 4(%sr2,%r20) 617#endif 618 b lws_exit 619 ldo -EFAULT(%r0),%r21 /* set errno */ 620 nop 621 nop 622 nop 623 nop 624 625 /* Two exception table entries, one for the load, 626 the other for the store. Either return -EFAULT. 627 Each of the entries must be relocated. */ 628 .section __ex_table,"aw" 629 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 630 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 631 .previous 632 633 634 /* Make sure nothing else is placed on this page */ 635 .align PAGE_SIZE 636END(linux_gateway_page) 637ENTRY(end_linux_gateway_page) 638 639 /* Relocate symbols assuming linux_gateway_page is mapped 640 to virtual address 0x0 */ 641 642#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 643 644 .section .rodata,"a" 645 646 .align PAGE_SIZE 647 /* Light-weight-syscall table */ 648 /* Start of lws table. */ 649ENTRY(lws_table) 650 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 651 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 652END(lws_table) 653 /* End of lws table */ 654 655 .align PAGE_SIZE 656ENTRY(sys_call_table) 657#include "syscall_table.S" 658END(sys_call_table) 659 660#ifdef CONFIG_64BIT 661 .align PAGE_SIZE 662ENTRY(sys_call_table64) 663#define SYSCALL_TABLE_64BIT 664#include "syscall_table.S" 665END(sys_call_table64) 666#endif 667 668 /* 669 All light-weight-syscall atomic operations 670 will use this set of locks 671 672 NOTE: The lws_lock_start symbol must be 673 at least 16-byte aligned for safe use 674 with ldcw. 675 */ 676 .section .data 677 .align PAGE_SIZE 678ENTRY(lws_lock_start) 679 /* lws locks */ 680 .rept 16 681 /* Keep locks aligned at 16-bytes */ 682 .word 1 683 .word 0 684 .word 0 685 .word 0 686 .endr 687END(lws_lock_start) 688 .previous 689 690.end 691 692 693