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 0xb4, lws uses 1 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 /* Unconditional branch to lws_start, located on the 57 same gateway page */ 58 b,n lws_start 59 60 /* Fill from 0xb4 to 0xe0 */ 61 .rept 11 62 KILL_INSN 63 .endr 64 65 /* This function MUST be located at 0xe0 for glibc's threading 66 mechanism to work. DO NOT MOVE THIS CODE EVER! */ 67set_thread_pointer: 68 gate .+8, %r0 /* increase privilege */ 69 depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 70 be 0(%sr7,%r31) /* return to user space */ 71 mtctl %r26, %cr27 /* move arg0 to the control register */ 72 73 /* Increase the chance of trapping if random jumps occur to this 74 address, fill from 0xf0 to 0x100 */ 75 .rept 4 76 KILL_INSN 77 .endr 78 79/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 80 .align 256 81linux_gateway_entry: 82 gate .+8, %r0 /* become privileged */ 83 mtsp %r0,%sr4 /* get kernel space into sr4 */ 84 mtsp %r0,%sr5 /* get kernel space into sr5 */ 85 mtsp %r0,%sr6 /* get kernel space into sr6 */ 86 mfsp %sr7,%r1 /* save user sr7 */ 87 mtsp %r1,%sr3 /* and store it in sr3 */ 88 89#ifdef CONFIG_64BIT 90 /* for now we can *always* set the W bit on entry to the syscall 91 * since we don't support wide userland processes. We could 92 * also save the current SM other than in r0 and restore it on 93 * exit from the syscall, and also use that value to know 94 * whether to do narrow or wide syscalls. -PB 95 */ 96 ssm PSW_SM_W, %r1 97 extrd,u %r1,PSW_W_BIT,1,%r1 98 /* sp must be aligned on 4, so deposit the W bit setting into 99 * the bottom of sp temporarily */ 100 or,ev %r1,%r30,%r30 101 b,n 1f 102 /* The top halves of argument registers must be cleared on syscall 103 * entry from narrow executable. 104 */ 105 depdi 0, 31, 32, %r26 106 depdi 0, 31, 32, %r25 107 depdi 0, 31, 32, %r24 108 depdi 0, 31, 32, %r23 109 depdi 0, 31, 32, %r22 110 depdi 0, 31, 32, %r21 1111: 112#endif 113 mfctl %cr30,%r1 114 xor %r1,%r30,%r30 /* ye olde xor trick */ 115 xor %r1,%r30,%r1 116 xor %r1,%r30,%r30 117 118 ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 119 120 /* N.B.: It is critical that we don't set sr7 to 0 until r30 121 * contains a valid kernel stack pointer. It is also 122 * critical that we don't start using the kernel stack 123 * until after sr7 has been set to 0. 124 */ 125 126 mtsp %r0,%sr7 /* get kernel space into sr7 */ 127 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 128 mfctl %cr30,%r1 /* get task ptr in %r1 */ 129 LDREG TI_TASK(%r1),%r1 130 131 /* Save some registers for sigcontext and potential task 132 switch (see entry.S for the details of which ones are 133 saved/restored). TASK_PT_PSW is zeroed so we can see whether 134 a process is on a syscall or not. For an interrupt the real 135 PSW value is stored. This is needed for gdb and sys_ptrace. */ 136 STREG %r0, TASK_PT_PSW(%r1) 137 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 138 STREG %r19, TASK_PT_GR19(%r1) 139 140 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 141#ifdef CONFIG_64BIT 142 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 143#if 0 144 xor %r19,%r2,%r2 /* clear bottom bit */ 145 depd,z %r19,1,1,%r19 146 std %r19,TASK_PT_PSW(%r1) 147#endif 148#endif 149 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 150 151 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 152 STREG %r21, TASK_PT_GR21(%r1) 153 STREG %r22, TASK_PT_GR22(%r1) 154 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 155 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 156 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 157 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 158 STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 159 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 160 STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ 161 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 162 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 163 164 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 165 save_fp %r27 /* or potential task switch */ 166 167 mfctl %cr11, %r27 /* i.e. SAR */ 168 STREG %r27, TASK_PT_SAR(%r1) 169 170 loadgp 171 172#ifdef CONFIG_64BIT 173 ldo -16(%r30),%r29 /* Reference param save area */ 174 copy %r19,%r2 /* W bit back to r2 */ 175#else 176 /* no need to save these on stack in wide mode because the first 8 177 * args are passed in registers */ 178 stw %r22, -52(%r30) /* 5th argument */ 179 stw %r21, -56(%r30) /* 6th argument */ 180#endif 181 182 /* Are we being ptraced? */ 183 mfctl %cr30, %r1 184 LDREG TI_TASK(%r1),%r1 185 ldw TASK_PTRACE(%r1), %r1 186 bb,<,n %r1,31,.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 /* Gate and ensure we return to userspace */ 427 gate .+8, %r0 428 depi 3, 31, 2, %r31 /* Ensure we return to userspace */ 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(%sr3, %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#ifdef CONFIG_SMP 533 /* Load start of lock table */ 534 ldil L%lws_lock_start, %r20 535 ldo R%lws_lock_start(%r20), %r28 536 537 /* Extract four bits from r26 and hash lock (Bits 4-7) */ 538 extru %r26, 27, 4, %r20 539 540 /* Find lock to use, the hash is either one of 0 to 541 15, multiplied by 16 (keep it 16-byte aligned) 542 and add to the lock table offset. */ 543 shlw %r20, 4, %r20 544 add %r20, %r28, %r20 545 546# if ENABLE_LWS_DEBUG 547 /* 548 DEBUG, check for deadlock! 549 If the thread register values are the same 550 then we were the one that locked it last and 551 this is a recurisve call that will deadlock. 552 We *must* giveup this call and fail. 553 */ 554 ldw 4(%sr2,%r20), %r28 /* Load thread register */ 555 /* WARNING: If cr27 cycles to the same value we have problems */ 556 mfctl %cr27, %r21 /* Get current thread register */ 557 cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 558 b lws_exit /* Return error! */ 559 ldo -EDEADLOCK(%r0), %r21 560cas_lock: 561 cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 562 ldo 1(%r0), %r28 /* 1st case */ 563 b lws_exit /* Contended... */ 564 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 565cas_nocontend: 566# endif 567/* ENABLE_LWS_DEBUG */ 568 569 LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 570 cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 571cas_wouldblock: 572 ldo 2(%r0), %r28 /* 2nd case */ 573 b lws_exit /* Contended... */ 574 ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 575#endif 576/* CONFIG_SMP */ 577 578 /* 579 prev = *addr; 580 if ( prev == old ) 581 *addr = new; 582 return prev; 583 */ 584 585 /* NOTES: 586 This all works becuse intr_do_signal 587 and schedule both check the return iasq 588 and see that we are on the kernel page 589 so this process is never scheduled off 590 or is ever sent any signal of any sort, 591 thus it is wholly atomic from usrspaces 592 perspective 593 */ 594cas_action: 595#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 596 /* DEBUG */ 597 mfctl %cr27, %r1 598 stw %r1, 4(%sr2,%r20) 599#endif 600 /* The load and store could fail */ 6011: ldw 0(%sr3,%r26), %r28 602 sub,<> %r28, %r25, %r0 6032: stw %r24, 0(%sr3,%r26) 604#ifdef CONFIG_SMP 605 /* Free lock */ 606 stw %r20, 0(%sr2,%r20) 607# if ENABLE_LWS_DEBUG 608 /* Clear thread register indicator */ 609 stw %r0, 4(%sr2,%r20) 610# endif 611#endif 612 /* Return to userspace, set no error */ 613 b lws_exit 614 copy %r0, %r21 615 6163: 617 /* Error occured on load or store */ 618#ifdef CONFIG_SMP 619 /* Free lock */ 620 stw %r20, 0(%sr2,%r20) 621# if ENABLE_LWS_DEBUG 622 stw %r0, 4(%sr2,%r20) 623# endif 624#endif 625 b lws_exit 626 ldo -EFAULT(%r0),%r21 /* set errno */ 627 nop 628 nop 629 nop 630 nop 631 632 /* Two exception table entries, one for the load, 633 the other for the store. Either return -EFAULT. 634 Each of the entries must be relocated. */ 635 .section __ex_table,"aw" 636 ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 637 ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 638 .previous 639 640 641 /* Make sure nothing else is placed on this page */ 642 .align PAGE_SIZE 643END(linux_gateway_page) 644ENTRY(end_linux_gateway_page) 645 646 /* Relocate symbols assuming linux_gateway_page is mapped 647 to virtual address 0x0 */ 648 649#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 650 651 .section .rodata,"a" 652 653 .align PAGE_SIZE 654 /* Light-weight-syscall table */ 655 /* Start of lws table. */ 656ENTRY(lws_table) 657 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 658 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 659END(lws_table) 660 /* End of lws table */ 661 662 .align PAGE_SIZE 663ENTRY(sys_call_table) 664#include "syscall_table.S" 665END(sys_call_table) 666 667#ifdef CONFIG_64BIT 668 .align PAGE_SIZE 669ENTRY(sys_call_table64) 670#define SYSCALL_TABLE_64BIT 671#include "syscall_table.S" 672END(sys_call_table64) 673#endif 674 675#ifdef CONFIG_SMP 676 /* 677 All light-weight-syscall atomic operations 678 will use this set of locks 679 680 NOTE: The lws_lock_start symbol must be 681 at least 16-byte aligned for safe use 682 with ldcw. 683 */ 684 .section .data 685 .align PAGE_SIZE 686ENTRY(lws_lock_start) 687 /* lws locks */ 688 .rept 16 689 /* Keep locks aligned at 16-bytes */ 690 .word 1 691 .word 0 692 .word 0 693 .word 0 694 .endr 695END(lws_lock_start) 696 .previous 697#endif 698/* CONFIG_SMP for lws_lock_start */ 699 700.end 701 702 703