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#ifdef CONFIG_64BIT 313 LDREG TASK_PT_GR22(%r1), %r22 314 LDREG TASK_PT_GR21(%r1), %r21 315 ldo -16(%r30),%r29 /* Reference param save area */ 316#endif 317 318 comiclr,>>= __NR_Linux_syscalls, %r20, %r0 319 b,n .Lsyscall_nosys 320 321 LDREGX %r20(%r19), %r19 322 323 /* If this is a sys_rt_sigreturn call, and the signal was received 324 * when not in_syscall, then we want to return via syscall_exit_rfi, 325 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 326 * trampoline code in signal.c). 327 */ 328 ldi __NR_rt_sigreturn,%r2 329 comb,= %r2,%r20,.Ltrace_rt_sigreturn 330.Ltrace_in_syscall: 331 ldil L%tracesys_exit,%r2 332 be 0(%sr7,%r19) 333 ldo R%tracesys_exit(%r2),%r2 334 335 /* Do *not* call this function on the gateway page, because it 336 makes a direct call to syscall_trace. */ 337 338tracesys_exit: 339 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 340 LDREG TI_TASK(%r1), %r1 341#ifdef CONFIG_64BIT 342 ldo -16(%r30),%r29 /* Reference param save area */ 343#endif 344 ldo TASK_REGS(%r1),%r26 345 bl do_syscall_trace_exit,%r2 346 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 347 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 348 LDREG TI_TASK(%r1), %r1 349 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 350 351 ldil L%syscall_exit,%r1 352 be,n R%syscall_exit(%sr7,%r1) 353 354.Ltrace_rt_sigreturn: 355 comib,<> 0,%r25,.Ltrace_in_syscall 356 ldil L%tracesys_sigexit,%r2 357 be 0(%sr7,%r19) 358 ldo R%tracesys_sigexit(%r2),%r2 359 360tracesys_sigexit: 361 ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 362 LDREG TI_TASK(%r1), %r1 363#ifdef CONFIG_64BIT 364 ldo -16(%r30),%r29 /* Reference param save area */ 365#endif 366 bl do_syscall_trace_exit,%r2 367 ldo TASK_REGS(%r1),%r26 368 369 ldil L%syscall_exit_rfi,%r1 370 be,n R%syscall_exit_rfi(%sr7,%r1) 371 372 373 /********************************************************* 374 32/64-bit Light-Weight-Syscall ABI 375 376 * - Indicates a hint for userspace inline asm 377 implementations. 378 379 Syscall number (caller-saves) 380 - %r20 381 * In asm clobber. 382 383 Argument registers (caller-saves) 384 - %r26, %r25, %r24, %r23, %r22 385 * In asm input. 386 387 Return registers (caller-saves) 388 - %r28 (return), %r21 (errno) 389 * In asm output. 390 391 Caller-saves registers 392 - %r1, %r27, %r29 393 - %r2 (return pointer) 394 - %r31 (ble link register) 395 * In asm clobber. 396 397 Callee-saves registers 398 - %r3-%r18 399 - %r30 (stack pointer) 400 * Not in asm clobber. 401 402 If userspace is 32-bit: 403 Callee-saves registers 404 - %r19 (32-bit PIC register) 405 406 Differences from 32-bit calling convention: 407 - Syscall number in %r20 408 - Additional argument register %r22 (arg4) 409 - Callee-saves %r19. 410 411 If userspace is 64-bit: 412 Callee-saves registers 413 - %r27 (64-bit PIC register) 414 415 Differences from 64-bit calling convention: 416 - Syscall number in %r20 417 - Additional argument register %r22 (arg4) 418 - Callee-saves %r27. 419 420 Error codes returned by entry path: 421 422 ENOSYS - r20 was an invalid LWS number. 423 424 *********************************************************/ 425lws_start: 426 427#ifdef CONFIG_64BIT 428 /* FIXME: If we are a 64-bit kernel just 429 * turn this on unconditionally. 430 */ 431 ssm PSW_SM_W, %r1 432 extrd,u %r1,PSW_W_BIT,1,%r1 433 /* sp must be aligned on 4, so deposit the W bit setting into 434 * the bottom of sp temporarily */ 435 or,ev %r1,%r30,%r30 436 437 /* Clip LWS number to a 32-bit value always */ 438 depdi 0, 31, 32, %r20 439#endif 440 441 /* Is the lws entry number valid? */ 442 comiclr,>> __NR_lws_entries, %r20, %r0 443 b,n lws_exit_nosys 444 445 /* WARNING: Trashing sr2 and sr3 */ 446 mfsp %sr7,%r1 /* get userspace into sr3 */ 447 mtsp %r1,%sr3 448 mtsp %r0,%sr2 /* get kernel space into sr2 */ 449 450 /* Load table start */ 451 ldil L%lws_table, %r1 452 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 453 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 454 455 /* Jump to lws, lws table pointers already relocated */ 456 be,n 0(%sr2,%r21) 457 458lws_exit_nosys: 459 ldo -ENOSYS(%r0),%r21 /* set errno */ 460 /* Fall through: Return to userspace */ 461 462lws_exit: 463#ifdef CONFIG_64BIT 464 /* decide whether to reset the wide mode bit 465 * 466 * For a syscall, the W bit is stored in the lowest bit 467 * of sp. Extract it and reset W if it is zero */ 468 extrd,u,*<> %r30,63,1,%r1 469 rsm PSW_SM_W, %r0 470 /* now reset the lowest bit of sp if it was set */ 471 xor %r30,%r1,%r30 472#endif 473 be,n 0(%sr7, %r31) 474 475 476 477 /*************************************************** 478 Implementing CAS as an atomic operation: 479 480 %r26 - Address to examine 481 %r25 - Old value to check (old) 482 %r24 - New value to set (new) 483 %r28 - Return prev through this register. 484 %r21 - Kernel error code 485 486 If debugging is DISabled: 487 488 %r21 has the following meanings: 489 490 EAGAIN - CAS is busy, ldcw failed, try again. 491 EFAULT - Read or write failed. 492 493 If debugging is enabled: 494 495 EDEADLOCK - CAS called recursively. 496 EAGAIN && r28 == 1 - CAS is busy. Lock contended. 497 EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 498 EFAULT - Read or write failed. 499 500 Scratch: r20, r28, r1 501 502 ****************************************************/ 503 504 /* Do not enable LWS debugging */ 505#define ENABLE_LWS_DEBUG 0 506 507 /* ELF64 Process entry path */ 508lws_compare_and_swap64: 509#ifdef CONFIG_64BIT 510 b,n lws_compare_and_swap 511#else 512 /* If we are not a 64-bit kernel, then we don't 513 * have 64-bit input registers, and calling 514 * the 64-bit LWS CAS returns ENOSYS. 515 */ 516 b,n lws_exit_nosys 517#endif 518 519 /* ELF32 Process entry path */ 520lws_compare_and_swap32: 521#ifdef CONFIG_64BIT 522 /* Clip all the input registers */ 523 depdi 0, 31, 32, %r26 524 depdi 0, 31, 32, %r25 525 depdi 0, 31, 32, %r24 526#endif 527 528lws_compare_and_swap: 529 /* Load start of lock table */ 530 ldil L%lws_lock_start, %r20 531 ldo R%lws_lock_start(%r20), %r28 532 533 /* Extract four bits from r26 and hash lock (Bits 4-7) */ 534 extru %r26, 27, 4, %r20 535 536 /* Find lock to use, the hash is either one of 0 to 537 15, multiplied by 16 (keep it 16-byte aligned) 538 and add to the lock table offset. */ 539 shlw %r20, 4, %r20 540 add %r20, %r28, %r20 541 542# if ENABLE_LWS_DEBUG 543 /* 544 DEBUG, check for deadlock! 545 If the thread register values are the same 546 then we were the one that locked it last and 547 this is a recurisve call that will deadlock. 548 We *must* giveup this call and fail. 549 */ 550 ldw 4(%sr2,%r20), %r28 /* Load thread register */ 551 /* WARNING: If cr27 cycles to the same value we have problems */ 552 mfctl %cr27, %r21 /* Get current thread register */ 553 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 554 b lws_exit /* Return error! */ 555 ldo -EDEADLOCK(%r0), %r21 556cas_lock: 557 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 558 ldo 1(%r0), %r28 /* 1st case */ 559 b lws_exit /* Contended... */ 560 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 561cas_nocontend: 562# endif 563/* ENABLE_LWS_DEBUG */ 564 565 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 566 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 567cas_wouldblock: 568 ldo 2(%r0), %r28 /* 2nd case */ 569 b lws_exit /* Contended... */ 570 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 571 572 /* 573 prev = *addr; 574 if ( prev == old ) 575 *addr = new; 576 return prev; 577 */ 578 579 /* NOTES: 580 This all works becuse intr_do_signal 581 and schedule both check the return iasq 582 and see that we are on the kernel page 583 so this process is never scheduled off 584 or is ever sent any signal of any sort, 585 thus it is wholly atomic from usrspaces 586 perspective 587 */ 588cas_action: 589#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 590 /* DEBUG */ 591 mfctl %cr27, %r1 592 stw %r1, 4(%sr2,%r20) 593#endif 594 /* The load and store could fail */ 5951: ldw 0(%sr3,%r26), %r28 596 sub,<> %r28, %r25, %r0 5972: stw %r24, 0(%sr3,%r26) 598 /* Free lock */ 599 stw %r20, 0(%sr2,%r20) 600#if ENABLE_LWS_DEBUG 601 /* Clear thread register indicator */ 602 stw %r0, 4(%sr2,%r20) 603#endif 604 /* Return to userspace, set no error */ 605 b lws_exit 606 copy %r0, %r21 607 6083: 609 /* Error occurred on load or store */ 610 /* Free lock */ 611 stw %r20, 0(%sr2,%r20) 612#if ENABLE_LWS_DEBUG 613 stw %r0, 4(%sr2,%r20) 614#endif 615 b lws_exit 616 ldo -EFAULT(%r0),%r21 /* set errno */ 617 nop 618 nop 619 nop 620 nop 621 622 /* Two exception table entries, one for the load, 623 the other for the store. Either return -EFAULT. 624 Each of the entries must be relocated. */ 625 .section __ex_table,"aw" 626 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 627 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 628 .previous 629 630 631 /* Make sure nothing else is placed on this page */ 632 .align PAGE_SIZE 633END(linux_gateway_page) 634ENTRY(end_linux_gateway_page) 635 636 /* Relocate symbols assuming linux_gateway_page is mapped 637 to virtual address 0x0 */ 638 639#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 640 641 .section .rodata,"a" 642 643 .align PAGE_SIZE 644 /* Light-weight-syscall table */ 645 /* Start of lws table. */ 646ENTRY(lws_table) 647 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 648 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 649END(lws_table) 650 /* End of lws table */ 651 652 .align PAGE_SIZE 653ENTRY(sys_call_table) 654#include "syscall_table.S" 655END(sys_call_table) 656 657#ifdef CONFIG_64BIT 658 .align PAGE_SIZE 659ENTRY(sys_call_table64) 660#define SYSCALL_TABLE_64BIT 661#include "syscall_table.S" 662END(sys_call_table64) 663#endif 664 665 /* 666 All light-weight-syscall atomic operations 667 will use this set of locks 668 669 NOTE: The lws_lock_start symbol must be 670 at least 16-byte aligned for safe use 671 with ldcw. 672 */ 673 .section .data 674 .align PAGE_SIZE 675ENTRY(lws_lock_start) 676 /* lws locks */ 677 .rept 16 678 /* Keep locks aligned at 16-bytes */ 679 .word 1 680 .word 0 681 .word 0 682 .word 0 683 .endr 684END(lws_lock_start) 685 .previous 686 687.end 688 689 690