1/* 2 * Linux/PA-RISC Project (http://www.parisc-linux.org/) 3 * 4 * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai> 5 * Licensed under the GNU GPL. 6 * thanks to Philipp Rumpf, Mike Shaver and various others 7 * sorry about the wall, puffin.. 8 */ 9 10#include <asm/asm-offsets.h> 11#include <asm/unistd.h> 12#include <asm/errno.h> 13#include <asm/page.h> 14#include <asm/psw.h> 15#include <asm/thread_info.h> 16#include <asm/assembly.h> 17#include <asm/processor.h> 18 19#include <linux/linkage.h> 20 21 /* We fill the empty parts of the gateway page with 22 * something that will kill the kernel or a 23 * userspace application. 24 */ 25#define KILL_INSN break 0,0 26 27 .level LEVEL 28 29 .text 30 31 .import syscall_exit,code 32 .import syscall_exit_rfi,code 33 34 /* Linux gateway page is aliased to virtual page 0 in the kernel 35 * address space. Since it is a gateway page it cannot be 36 * dereferenced, so null pointers will still fault. We start 37 * the actual entry point at 0x100. We put break instructions 38 * at the beginning of the page to trap null indirect function 39 * pointers. 40 */ 41 42 .align PAGE_SIZE 43ENTRY(linux_gateway_page) 44 45 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 46 .rept 44 47 KILL_INSN 48 .endr 49 50 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */ 51 /* Light-weight-syscall entry must always be located at 0xb0 */ 52 /* WARNING: Keep this number updated with table size changes */ 53#define __NR_lws_entries (2) 54 55lws_entry: 56 gate lws_start, %r0 /* increase privilege */ 57 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 58 59 /* Fill from 0xb8 to 0xe0 */ 60 .rept 10 61 KILL_INSN 62 .endr 63 64 /* This function MUST be located at 0xe0 for glibc's threading 65 mechanism to work. DO NOT MOVE THIS CODE EVER! */ 66set_thread_pointer: 67 gate .+8, %r0 /* increase privilege */ 68 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 69 be 0(%sr7,%r31) /* return to user space */ 70 mtctl %r26, %cr27 /* move arg0 to the control register */ 71 72 /* Increase the chance of trapping if random jumps occur to this 73 address, fill from 0xf0 to 0x100 */ 74 .rept 4 75 KILL_INSN 76 .endr 77 78/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 79 .align 256 80linux_gateway_entry: 81 gate .+8, %r0 /* become privileged */ 82 mtsp %r0,%sr4 /* get kernel space into sr4 */ 83 mtsp %r0,%sr5 /* get kernel space into sr5 */ 84 mtsp %r0,%sr6 /* get kernel space into sr6 */ 85 mfsp %sr7,%r1 /* save user sr7 */ 86 mtsp %r1,%sr3 /* and store it in sr3 */ 87 88#ifdef CONFIG_64BIT 89 /* for now we can *always* set the W bit on entry to the syscall 90 * since we don't support wide userland processes. We could 91 * also save the current SM other than in r0 and restore it on 92 * exit from the syscall, and also use that value to know 93 * whether to do narrow or wide syscalls. -PB 94 */ 95 ssm PSW_SM_W, %r1 96 extrd,u %r1,PSW_W_BIT,1,%r1 97 /* sp must be aligned on 4, so deposit the W bit setting into 98 * the bottom of sp temporarily */ 99 or,ev %r1,%r30,%r30 100 b,n 1f 101 /* The top halves of argument registers must be cleared on syscall 102 * entry from narrow executable. 103 */ 104 depdi 0, 31, 32, %r26 105 depdi 0, 31, 32, %r25 106 depdi 0, 31, 32, %r24 107 depdi 0, 31, 32, %r23 108 depdi 0, 31, 32, %r22 109 depdi 0, 31, 32, %r21 1101: 111#endif 112 mfctl %cr30,%r1 113 xor %r1,%r30,%r30 /* ye olde xor trick */ 114 xor %r1,%r30,%r1 115 xor %r1,%r30,%r30 116 117 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 118 119 /* N.B.: It is critical that we don't set sr7 to 0 until r30 120 * contains a valid kernel stack pointer. It is also 121 * critical that we don't start using the kernel stack 122 * until after sr7 has been set to 0. 123 */ 124 125 mtsp %r0,%sr7 /* get kernel space into sr7 */ 126 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 127 mfctl %cr30,%r1 /* get task ptr in %r1 */ 128 LDREG TI_TASK(%r1),%r1 129 130 /* Save some registers for sigcontext and potential task 131 switch (see entry.S for the details of which ones are 132 saved/restored). TASK_PT_PSW is zeroed so we can see whether 133 a process is on a syscall or not. For an interrupt the real 134 PSW value is stored. This is needed for gdb and sys_ptrace. */ 135 STREG %r0, TASK_PT_PSW(%r1) 136 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 137 STREG %r19, TASK_PT_GR19(%r1) 138 139 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 140#ifdef CONFIG_64BIT 141 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 142#if 0 143 xor %r19,%r2,%r2 /* clear bottom bit */ 144 depd,z %r19,1,1,%r19 145 std %r19,TASK_PT_PSW(%r1) 146#endif 147#endif 148 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 149 150 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 151 STREG %r21, TASK_PT_GR21(%r1) 152 STREG %r22, TASK_PT_GR22(%r1) 153 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 154 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 155 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 156 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 157 STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 158 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 159 STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ 160 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 161 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 162 163 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 164 save_fp %r27 /* or potential task switch */ 165 166 mfctl %cr11, %r27 /* i.e. SAR */ 167 STREG %r27, TASK_PT_SAR(%r1) 168 169 loadgp 170 171#ifdef CONFIG_64BIT 172 ldo -16(%r30),%r29 /* Reference param save area */ 173 copy %r19,%r2 /* W bit back to r2 */ 174#else 175 /* no need to save these on stack in wide mode because the first 8 176 * args are passed in registers */ 177 stw %r22, -52(%r30) /* 5th argument */ 178 stw %r21, -56(%r30) /* 6th argument */ 179#endif 180 181 /* Are we being ptraced? */ 182 mfctl %cr30, %r1 183 LDREG TI_TASK(%r1),%r1 184 ldw TASK_PTRACE(%r1), %r1 185 bb,<,n %r1,31,.Ltracesys 186 187 /* Note! We cannot use the syscall table that is mapped 188 nearby since the gateway page is mapped execute-only. */ 189 190#ifdef CONFIG_64BIT 191 ldil L%sys_call_table, %r1 192 or,= %r2,%r2,%r2 193 addil L%(sys_call_table64-sys_call_table), %r1 194 ldo R%sys_call_table(%r1), %r19 195 or,= %r2,%r2,%r2 196 ldo R%sys_call_table64(%r1), %r19 197#else 198 ldil L%sys_call_table, %r1 199 ldo R%sys_call_table(%r1), %r19 200#endif 201 comiclr,>> __NR_Linux_syscalls, %r20, %r0 202 b,n .Lsyscall_nosys 203 204 LDREGX %r20(%r19), %r19 205 206 /* If this is a sys_rt_sigreturn call, and the signal was received 207 * when not in_syscall, then we want to return via syscall_exit_rfi, 208 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 209 * trampoline code in signal.c). 210 */ 211 ldi __NR_rt_sigreturn,%r2 212 comb,= %r2,%r20,.Lrt_sigreturn 213.Lin_syscall: 214 ldil L%syscall_exit,%r2 215 be 0(%sr7,%r19) 216 ldo R%syscall_exit(%r2),%r2 217.Lrt_sigreturn: 218 comib,<> 0,%r25,.Lin_syscall 219 ldil L%syscall_exit_rfi,%r2 220 be 0(%sr7,%r19) 221 ldo R%syscall_exit_rfi(%r2),%r2 222 223 /* Note! Because we are not running where we were linked, any 224 calls to functions external to this file must be indirect. To 225 be safe, we apply the opposite rule to functions within this 226 file, with local labels given to them to ensure correctness. */ 227 228.Lsyscall_nosys: 229syscall_nosys: 230 ldil L%syscall_exit,%r1 231 be R%syscall_exit(%sr7,%r1) 232 ldo -ENOSYS(%r0),%r28 /* set errno */ 233 234 235/* Warning! This trace code is a virtual duplicate of the code above so be 236 * sure to maintain both! */ 237.Ltracesys: 238tracesys: 239 /* Need to save more registers so the debugger can see where we 240 * are. This saves only the lower 8 bits of PSW, so that the C 241 * bit is still clear on syscalls, and the D bit is set if this 242 * full register save path has been executed. We check the D 243 * bit on syscall_return_rfi to determine which registers to 244 * restore. An interrupt results in a full PSW saved with the 245 * C bit set, a non-straced syscall entry results in C and D clear 246 * in the saved PSW. 247 */ 248 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 249 LDREG TI_TASK(%r1), %r1 250 ssm 0,%r2 251 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ 252 mfsp %sr0,%r2 253 STREG %r2,TASK_PT_SR0(%r1) 254 mfsp %sr1,%r2 255 STREG %r2,TASK_PT_SR1(%r1) 256 mfsp %sr2,%r2 257 STREG %r2,TASK_PT_SR2(%r1) 258 mfsp %sr3,%r2 259 STREG %r2,TASK_PT_SR3(%r1) 260 STREG %r2,TASK_PT_SR4(%r1) 261 STREG %r2,TASK_PT_SR5(%r1) 262 STREG %r2,TASK_PT_SR6(%r1) 263 STREG %r2,TASK_PT_SR7(%r1) 264 STREG %r2,TASK_PT_IASQ0(%r1) 265 STREG %r2,TASK_PT_IASQ1(%r1) 266 LDREG TASK_PT_GR31(%r1),%r2 267 STREG %r2,TASK_PT_IAOQ0(%r1) 268 ldo 4(%r2),%r2 269 STREG %r2,TASK_PT_IAOQ1(%r1) 270 ldo TASK_REGS(%r1),%r2 271 /* reg_save %r2 */ 272 STREG %r3,PT_GR3(%r2) 273 STREG %r4,PT_GR4(%r2) 274 STREG %r5,PT_GR5(%r2) 275 STREG %r6,PT_GR6(%r2) 276 STREG %r7,PT_GR7(%r2) 277 STREG %r8,PT_GR8(%r2) 278 STREG %r9,PT_GR9(%r2) 279 STREG %r10,PT_GR10(%r2) 280 STREG %r11,PT_GR11(%r2) 281 STREG %r12,PT_GR12(%r2) 282 STREG %r13,PT_GR13(%r2) 283 STREG %r14,PT_GR14(%r2) 284 STREG %r15,PT_GR15(%r2) 285 STREG %r16,PT_GR16(%r2) 286 STREG %r17,PT_GR17(%r2) 287 STREG %r18,PT_GR18(%r2) 288 /* Finished saving things for the debugger */ 289 290 copy %r2,%r26 291 ldil L%do_syscall_trace_enter,%r1 292 ldil L%tracesys_next,%r2 293 be R%do_syscall_trace_enter(%sr7,%r1) 294 ldo R%tracesys_next(%r2),%r2 295 296tracesys_next: 297 /* do_syscall_trace_enter either returned the syscallno, or -1L, 298 * so we skip restoring the PT_GR20 below, since we pulled it from 299 * task->thread.regs.gr[20] above. 300 */ 301 copy %ret0,%r20 302 ldil L%sys_call_table,%r1 303 ldo R%sys_call_table(%r1), %r19 304 305 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 306 LDREG TI_TASK(%r1), %r1 307 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 308 LDREG TASK_PT_GR25(%r1), %r25 309 LDREG TASK_PT_GR24(%r1), %r24 310 LDREG TASK_PT_GR23(%r1), %r23 311#ifdef CONFIG_64BIT 312 LDREG TASK_PT_GR22(%r1), %r22 313 LDREG TASK_PT_GR21(%r1), %r21 314 ldo -16(%r30),%r29 /* Reference param save area */ 315#endif 316 317 comiclr,>>= __NR_Linux_syscalls, %r20, %r0 318 b,n .Lsyscall_nosys 319 320 LDREGX %r20(%r19), %r19 321 322 /* If this is a sys_rt_sigreturn call, and the signal was received 323 * when not in_syscall, then we want to return via syscall_exit_rfi, 324 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 325 * trampoline code in signal.c). 326 */ 327 ldi __NR_rt_sigreturn,%r2 328 comb,= %r2,%r20,.Ltrace_rt_sigreturn 329.Ltrace_in_syscall: 330 ldil L%tracesys_exit,%r2 331 be 0(%sr7,%r19) 332 ldo R%tracesys_exit(%r2),%r2 333 334 /* Do *not* call this function on the gateway page, because it 335 makes a direct call to syscall_trace. */ 336 337tracesys_exit: 338 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 339 LDREG TI_TASK(%r1), %r1 340#ifdef CONFIG_64BIT 341 ldo -16(%r30),%r29 /* Reference param save area */ 342#endif 343 ldo TASK_REGS(%r1),%r26 344 bl do_syscall_trace_exit,%r2 345 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 346 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 347 LDREG TI_TASK(%r1), %r1 348 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 349 350 ldil L%syscall_exit,%r1 351 be,n R%syscall_exit(%sr7,%r1) 352 353.Ltrace_rt_sigreturn: 354 comib,<> 0,%r25,.Ltrace_in_syscall 355 ldil L%tracesys_sigexit,%r2 356 be 0(%sr7,%r19) 357 ldo R%tracesys_sigexit(%r2),%r2 358 359tracesys_sigexit: 360 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 361 LDREG TI_TASK(%r1), %r1 362#ifdef CONFIG_64BIT 363 ldo -16(%r30),%r29 /* Reference param save area */ 364#endif 365 bl do_syscall_trace_exit,%r2 366 ldo TASK_REGS(%r1),%r26 367 368 ldil L%syscall_exit_rfi,%r1 369 be,n R%syscall_exit_rfi(%sr7,%r1) 370 371 372 /********************************************************* 373 32/64-bit Light-Weight-Syscall ABI 374 375 * - Indicates a hint for userspace inline asm 376 implementations. 377 378 Syscall number (caller-saves) 379 - %r20 380 * In asm clobber. 381 382 Argument registers (caller-saves) 383 - %r26, %r25, %r24, %r23, %r22 384 * In asm input. 385 386 Return registers (caller-saves) 387 - %r28 (return), %r21 (errno) 388 * In asm output. 389 390 Caller-saves registers 391 - %r1, %r27, %r29 392 - %r2 (return pointer) 393 - %r31 (ble link register) 394 * In asm clobber. 395 396 Callee-saves registers 397 - %r3-%r18 398 - %r30 (stack pointer) 399 * Not in asm clobber. 400 401 If userspace is 32-bit: 402 Callee-saves registers 403 - %r19 (32-bit PIC register) 404 405 Differences from 32-bit calling convention: 406 - Syscall number in %r20 407 - Additional argument register %r22 (arg4) 408 - Callee-saves %r19. 409 410 If userspace is 64-bit: 411 Callee-saves registers 412 - %r27 (64-bit PIC register) 413 414 Differences from 64-bit calling convention: 415 - Syscall number in %r20 416 - Additional argument register %r22 (arg4) 417 - Callee-saves %r27. 418 419 Error codes returned by entry path: 420 421 ENOSYS - r20 was an invalid LWS number. 422 423 *********************************************************/ 424lws_start: 425 426#ifdef CONFIG_64BIT 427 /* FIXME: If we are a 64-bit kernel just 428 * turn this on unconditionally. 429 */ 430 ssm PSW_SM_W, %r1 431 extrd,u %r1,PSW_W_BIT,1,%r1 432 /* sp must be aligned on 4, so deposit the W bit setting into 433 * the bottom of sp temporarily */ 434 or,ev %r1,%r30,%r30 435 436 /* Clip LWS number to a 32-bit value always */ 437 depdi 0, 31, 32, %r20 438#endif 439 440 /* Is the lws entry number valid? */ 441 comiclr,>> __NR_lws_entries, %r20, %r0 442 b,n lws_exit_nosys 443 444 /* WARNING: Trashing sr2 and sr3 */ 445 mfsp %sr7,%r1 /* get userspace into sr3 */ 446 mtsp %r1,%sr3 447 mtsp %r0,%sr2 /* get kernel space into sr2 */ 448 449 /* Load table start */ 450 ldil L%lws_table, %r1 451 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 452 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 453 454 /* Jump to lws, lws table pointers already relocated */ 455 be,n 0(%sr2,%r21) 456 457lws_exit_nosys: 458 ldo -ENOSYS(%r0),%r21 /* set errno */ 459 /* Fall through: Return to userspace */ 460 461lws_exit: 462#ifdef CONFIG_64BIT 463 /* decide whether to reset the wide mode bit 464 * 465 * For a syscall, the W bit is stored in the lowest bit 466 * of sp. Extract it and reset W if it is zero */ 467 extrd,u,*<> %r30,63,1,%r1 468 rsm PSW_SM_W, %r0 469 /* now reset the lowest bit of sp if it was set */ 470 xor %r30,%r1,%r30 471#endif 472 be,n 0(%sr7, %r31) 473 474 475 476 /*************************************************** 477 Implementing CAS as an atomic operation: 478 479 %r26 - Address to examine 480 %r25 - Old value to check (old) 481 %r24 - New value to set (new) 482 %r28 - Return prev through this register. 483 %r21 - Kernel error code 484 485 If debugging is DISabled: 486 487 %r21 has the following meanings: 488 489 EAGAIN - CAS is busy, ldcw failed, try again. 490 EFAULT - Read or write failed. 491 492 If debugging is enabled: 493 494 EDEADLOCK - CAS called recursively. 495 EAGAIN && r28 == 1 - CAS is busy. Lock contended. 496 EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 497 EFAULT - Read or write failed. 498 499 Scratch: r20, r28, r1 500 501 ****************************************************/ 502 503 /* Do not enable LWS debugging */ 504#define ENABLE_LWS_DEBUG 0 505 506 /* ELF64 Process entry path */ 507lws_compare_and_swap64: 508#ifdef CONFIG_64BIT 509 b,n lws_compare_and_swap 510#else 511 /* If we are not a 64-bit kernel, then we don't 512 * have 64-bit input registers, and calling 513 * the 64-bit LWS CAS returns ENOSYS. 514 */ 515 b,n lws_exit_nosys 516#endif 517 518 /* ELF32 Process entry path */ 519lws_compare_and_swap32: 520#ifdef CONFIG_64BIT 521 /* Clip all the input registers */ 522 depdi 0, 31, 32, %r26 523 depdi 0, 31, 32, %r25 524 depdi 0, 31, 32, %r24 525#endif 526 527lws_compare_and_swap: 528 /* Load start of lock table */ 529 ldil L%lws_lock_start, %r20 530 ldo R%lws_lock_start(%r20), %r28 531 532 /* Extract four bits from r26 and hash lock (Bits 4-7) */ 533 extru %r26, 27, 4, %r20 534 535 /* Find lock to use, the hash is either one of 0 to 536 15, multiplied by 16 (keep it 16-byte aligned) 537 and add to the lock table offset. */ 538 shlw %r20, 4, %r20 539 add %r20, %r28, %r20 540 541# if ENABLE_LWS_DEBUG 542 /* 543 DEBUG, check for deadlock! 544 If the thread register values are the same 545 then we were the one that locked it last and 546 this is a recurisve call that will deadlock. 547 We *must* giveup this call and fail. 548 */ 549 ldw 4(%sr2,%r20), %r28 /* Load thread register */ 550 /* WARNING: If cr27 cycles to the same value we have problems */ 551 mfctl %cr27, %r21 /* Get current thread register */ 552 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 553 b lws_exit /* Return error! */ 554 ldo -EDEADLOCK(%r0), %r21 555cas_lock: 556 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 557 ldo 1(%r0), %r28 /* 1st case */ 558 b lws_exit /* Contended... */ 559 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 560cas_nocontend: 561# endif 562/* ENABLE_LWS_DEBUG */ 563 564 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 565 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 566cas_wouldblock: 567 ldo 2(%r0), %r28 /* 2nd case */ 568 b lws_exit /* Contended... */ 569 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 570 571 /* 572 prev = *addr; 573 if ( prev == old ) 574 *addr = new; 575 return prev; 576 */ 577 578 /* NOTES: 579 This all works becuse intr_do_signal 580 and schedule both check the return iasq 581 and see that we are on the kernel page 582 so this process is never scheduled off 583 or is ever sent any signal of any sort, 584 thus it is wholly atomic from usrspaces 585 perspective 586 */ 587cas_action: 588#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 589 /* DEBUG */ 590 mfctl %cr27, %r1 591 stw %r1, 4(%sr2,%r20) 592#endif 593 /* The load and store could fail */ 5941: ldw 0(%sr3,%r26), %r28 595 sub,<> %r28, %r25, %r0 5962: stw %r24, 0(%sr3,%r26) 597 /* Free lock */ 598 stw %r20, 0(%sr2,%r20) 599#if ENABLE_LWS_DEBUG 600 /* Clear thread register indicator */ 601 stw %r0, 4(%sr2,%r20) 602#endif 603 /* Return to userspace, set no error */ 604 b lws_exit 605 copy %r0, %r21 606 6073: 608 /* Error occurred on load or store */ 609 /* Free lock */ 610 stw %r20, 0(%sr2,%r20) 611#if ENABLE_LWS_DEBUG 612 stw %r0, 4(%sr2,%r20) 613#endif 614 b lws_exit 615 ldo -EFAULT(%r0),%r21 /* set errno */ 616 nop 617 nop 618 nop 619 nop 620 621 /* Two exception table entries, one for the load, 622 the other for the store. Either return -EFAULT. 623 Each of the entries must be relocated. */ 624 .section __ex_table,"aw" 625 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 626 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 627 .previous 628 629 630 /* Make sure nothing else is placed on this page */ 631 .align PAGE_SIZE 632END(linux_gateway_page) 633ENTRY(end_linux_gateway_page) 634 635 /* Relocate symbols assuming linux_gateway_page is mapped 636 to virtual address 0x0 */ 637 638#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 639 640 .section .rodata,"a" 641 642 .align PAGE_SIZE 643 /* Light-weight-syscall table */ 644 /* Start of lws table. */ 645ENTRY(lws_table) 646 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 647 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 648END(lws_table) 649 /* End of lws table */ 650 651 .align PAGE_SIZE 652ENTRY(sys_call_table) 653#include "syscall_table.S" 654END(sys_call_table) 655 656#ifdef CONFIG_64BIT 657 .align PAGE_SIZE 658ENTRY(sys_call_table64) 659#define SYSCALL_TABLE_64BIT 660#include "syscall_table.S" 661END(sys_call_table64) 662#endif 663 664 /* 665 All light-weight-syscall atomic operations 666 will use this set of locks 667 668 NOTE: The lws_lock_start symbol must be 669 at least 16-byte aligned for safe use 670 with ldcw. 671 */ 672 .section .data 673 .align PAGE_SIZE 674ENTRY(lws_lock_start) 675 /* lws locks */ 676 .rept 16 677 /* Keep locks aligned at 16-bytes */ 678 .word 1 679 .word 0 680 .word 0 681 .word 0 682 .endr 683END(lws_lock_start) 684 .previous 685 686.end 687 688 689