1/* 2 * Linux/PA-RISC Project (http://www.parisc-linux.org/) 3 * 4 * System call entry code / Linux gateway page 5 * Copyright (c) Matthew Wilcox 1999 <willy@infradead.org> 6 * Licensed under the GNU GPL. 7 * thanks to Philipp Rumpf, Mike Shaver and various others 8 * sorry about the wall, puffin.. 9 */ 10 11/* 12How does the Linux gateway page on PA-RISC work? 13------------------------------------------------ 14The Linux gateway page on PA-RISC is "special". 15It actually has PAGE_GATEWAY bits set (this is linux terminology; in parisc 16terminology it's Execute, promote to PL0) in the page map. So anything 17executing on this page executes with kernel level privilege (there's more to it 18than that: to have this happen, you also have to use a branch with a ,gate 19completer to activate the privilege promotion). The upshot is that everything 20that runs on the gateway page runs at kernel privilege but with the current 21user process address space (although you have access to kernel space via %sr2). 22For the 0x100 syscall entry, we redo the space registers to point to the kernel 23address space (preserving the user address space in %sr3), move to wide mode if 24required, save the user registers and branch into the kernel syscall entry 25point. For all the other functions, we execute at kernel privilege but don't 26flip address spaces. The basic upshot of this is that these code snippets are 27executed atomically (because the kernel can't be pre-empted) and they may 28perform architecturally forbidden (to PL3) operations (like setting control 29registers). 30*/ 31 32 33#include <asm/asm-offsets.h> 34#include <asm/unistd.h> 35#include <asm/errno.h> 36#include <asm/page.h> 37#include <asm/psw.h> 38#include <asm/thread_info.h> 39#include <asm/assembly.h> 40#include <asm/processor.h> 41#include <asm/cache.h> 42#include <asm/spinlock_types.h> 43 44#include <linux/linkage.h> 45 46 /* We fill the empty parts of the gateway page with 47 * something that will kill the kernel or a 48 * userspace application. 49 */ 50#define KILL_INSN break 0,0 51 52 .level PA_ASM_LEVEL 53 54 .macro lws_pagefault_disable reg1,reg2 55 mfctl %cr30, \reg2 56 ldo TASK_PAGEFAULT_DISABLED(\reg2), \reg2 57 ldw 0(%sr2,\reg2), \reg1 58 ldo 1(\reg1), \reg1 59 stw \reg1, 0(%sr2,\reg2) 60 .endm 61 62 .macro lws_pagefault_enable reg1,reg2 63 mfctl %cr30, \reg2 64 ldo TASK_PAGEFAULT_DISABLED(\reg2), \reg2 65 ldw 0(%sr2,\reg2), \reg1 66 ldo -1(\reg1), \reg1 67 stw \reg1, 0(%sr2,\reg2) 68 .endm 69 70 /* raise exception if spinlock content is not zero or 71 * __ARCH_SPIN_LOCK_UNLOCKED_VAL */ 72 .macro spinlock_check spin_val,tmpreg 73#ifdef CONFIG_LIGHTWEIGHT_SPINLOCK_CHECK 74 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, \tmpreg 75 andcm,= \spin_val, \tmpreg, %r0 76 .word SPINLOCK_BREAK_INSN 77#endif 78 .endm 79 80 .text 81 82 .import syscall_exit,code 83 .import syscall_exit_rfi,code 84 85 /* Linux gateway page is aliased to virtual page 0 in the kernel 86 * address space. Since it is a gateway page it cannot be 87 * dereferenced, so null pointers will still fault. We start 88 * the actual entry point at 0x100. We put break instructions 89 * at the beginning of the page to trap null indirect function 90 * pointers. 91 */ 92 93 .align PAGE_SIZE 94ENTRY(linux_gateway_page) 95 96 /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 97 .rept 44 98 KILL_INSN 99 .endr 100 101 /* ADDRESS 0xb0 to 0xb8, lws uses two insns for entry */ 102 /* Light-weight-syscall entry must always be located at 0xb0 */ 103 /* WARNING: Keep this number updated with table size changes */ 104#define __NR_lws_entries (5) 105 106lws_entry: 107 gate lws_start, %r0 /* increase privilege */ 108 depi PRIV_USER, 31, 2, %r31 /* Ensure we return into user mode. */ 109 110 /* Fill from 0xb8 to 0xe0 */ 111 .rept 10 112 KILL_INSN 113 .endr 114 115 /* This function MUST be located at 0xe0 for glibc's threading 116 mechanism to work. DO NOT MOVE THIS CODE EVER! */ 117set_thread_pointer: 118 gate .+8, %r0 /* increase privilege */ 119 depi PRIV_USER, 31, 2, %r31 /* Ensure we return into user mode. */ 120 be 0(%sr7,%r31) /* return to user space */ 121 mtctl %r26, %cr27 /* move arg0 to the control register */ 122 123 /* Increase the chance of trapping if random jumps occur to this 124 address, fill from 0xf0 to 0x100 */ 125 .rept 4 126 KILL_INSN 127 .endr 128 129/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 130 .align LINUX_GATEWAY_ADDR 131linux_gateway_entry: 132 gate .+8, %r0 /* become privileged */ 133 mtsp %r0,%sr4 /* get kernel space into sr4 */ 134 mtsp %r0,%sr5 /* get kernel space into sr5 */ 135 mtsp %r0,%sr6 /* get kernel space into sr6 */ 136 137#ifdef CONFIG_64BIT 138 /* Store W bit on entry to the syscall in case it's a wide userland 139 * process. */ 140 ssm PSW_SM_W, %r1 141 extrd,u %r1,PSW_W_BIT,1,%r1 142 /* sp must be aligned on 4, so deposit the W bit setting into 143 * the bottom of sp temporarily */ 144 or,ev %r1,%r30,%r30 145 b,n 1f 146 /* The top halves of argument registers must be cleared on syscall 147 * entry from narrow executable. 148 */ 149 depdi 0, 31, 32, %r26 150 depdi 0, 31, 32, %r25 151 depdi 0, 31, 32, %r24 152 depdi 0, 31, 32, %r23 153 depdi 0, 31, 32, %r22 154 depdi 0, 31, 32, %r21 1551: 156#endif 157 158 /* We use a rsm/ssm pair to prevent sr3 from being clobbered 159 * by external interrupts. 160 */ 161 mfsp %sr7,%r1 /* save user sr7 */ 162 rsm PSW_SM_I, %r0 /* disable interrupts */ 163 mtsp %r1,%sr3 /* and store it in sr3 */ 164 165 mfctl %cr30,%r1 166 xor %r1,%r30,%r30 /* ye olde xor trick */ 167 xor %r1,%r30,%r1 168 xor %r1,%r30,%r30 169 170 LDREG TASK_STACK(%r30),%r30 /* set up kernel stack */ 171 ldo FRAME_SIZE(%r30),%r30 172 /* N.B.: It is critical that we don't set sr7 to 0 until r30 173 * contains a valid kernel stack pointer. It is also 174 * critical that we don't start using the kernel stack 175 * until after sr7 has been set to 0. 176 */ 177 178 mtsp %r0,%sr7 /* get kernel space into sr7 */ 179 ssm PSW_SM_I, %r0 /* enable interrupts */ 180 STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 181 mfctl %cr30,%r1 /* get task ptr in %r1 */ 182 183 /* Save some registers for sigcontext and potential task 184 switch (see entry.S for the details of which ones are 185 saved/restored). TASK_PT_PSW is zeroed so we can see whether 186 a process is on a syscall or not. For an interrupt the real 187 PSW value is stored. This is needed for gdb and sys_ptrace. */ 188 STREG %r0, TASK_PT_PSW(%r1) 189 STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 190 STREG %r19, TASK_PT_GR19(%r1) 191 192 LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 193#ifdef CONFIG_64BIT 194 extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 195#if 0 196 xor %r19,%r2,%r2 /* clear bottom bit */ 197 depd,z %r19,1,1,%r19 198 std %r19,TASK_PT_PSW(%r1) 199#endif 200#endif 201 STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 202 203 STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 204 STREG %r21, TASK_PT_GR21(%r1) 205 STREG %r22, TASK_PT_GR22(%r1) 206 STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 207 STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 208 STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 209 STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 210 STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 211 STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 212 STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */ 213 STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 214 STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 215 216 ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 217 save_fp %r27 /* or potential task switch */ 218 219 mfctl %cr11, %r27 /* i.e. SAR */ 220 STREG %r27, TASK_PT_SAR(%r1) 221 222 loadgp 223 224#ifdef CONFIG_64BIT 225 ldo -16(%r30),%r29 /* Reference param save area */ 226 copy %r19,%r2 /* W bit back to r2 */ 227#else 228 /* no need to save these on stack in wide mode because the first 8 229 * args are passed in registers */ 230 stw %r22, -52(%r30) /* 5th argument */ 231 stw %r21, -56(%r30) /* 6th argument */ 232#endif 233 234 /* Are we being ptraced? */ 235 mfctl %cr30, %r1 236 LDREG TASK_TI_FLAGS(%r1),%r1 237 ldi _TIF_SYSCALL_TRACE_MASK, %r19 238 and,COND(=) %r1, %r19, %r0 239 b,n .Ltracesys 240 241 /* Note! We cannot use the syscall table that is mapped 242 nearby since the gateway page is mapped execute-only. */ 243 244#ifdef CONFIG_64BIT 245 ldil L%sys_call_table, %r1 246 or,ev %r2,%r2,%r2 247 ldil L%sys_call_table64, %r1 248 ldo R%sys_call_table(%r1), %r19 249 or,ev %r2,%r2,%r2 250 ldo R%sys_call_table64(%r1), %r19 251#else 252 load32 sys_call_table, %r19 253#endif 254 comiclr,>> __NR_Linux_syscalls, %r20, %r0 255 b,n .Lsyscall_nosys 256 257 LDREGX %r20(%r19), %r19 258 259 /* If this is a sys_rt_sigreturn call, and the signal was received 260 * when not in_syscall, then we want to return via syscall_exit_rfi, 261 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 262 * trampoline code in signal.c). 263 */ 264 ldi __NR_rt_sigreturn,%r2 265 comb,= %r2,%r20,.Lrt_sigreturn 266.Lin_syscall: 267 ldil L%syscall_exit,%r2 268 be 0(%sr7,%r19) 269 ldo R%syscall_exit(%r2),%r2 270.Lrt_sigreturn: 271 comib,<> 0,%r25,.Lin_syscall 272 ldil L%syscall_exit_rfi,%r2 273 be 0(%sr7,%r19) 274 ldo R%syscall_exit_rfi(%r2),%r2 275 276 /* Note! Because we are not running where we were linked, any 277 calls to functions external to this file must be indirect. To 278 be safe, we apply the opposite rule to functions within this 279 file, with local labels given to them to ensure correctness. */ 280 281.Lsyscall_nosys: 282syscall_nosys: 283 ldil L%syscall_exit,%r1 284 be R%syscall_exit(%sr7,%r1) 285 ldo -ENOSYS(%r0),%r28 /* set errno */ 286 287 288/* Warning! This trace code is a virtual duplicate of the code above so be 289 * sure to maintain both! */ 290.Ltracesys: 291tracesys: 292 /* Need to save more registers so the debugger can see where we 293 * are. This saves only the lower 8 bits of PSW, so that the C 294 * bit is still clear on syscalls, and the D bit is set if this 295 * full register save path has been executed. We check the D 296 * bit on syscall_return_rfi to determine which registers to 297 * restore. An interrupt results in a full PSW saved with the 298 * C bit set, a non-straced syscall entry results in C and D clear 299 * in the saved PSW. 300 */ 301 mfctl %cr30,%r1 /* get task ptr */ 302 ssm 0,%r2 303 STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ 304 mfsp %sr0,%r2 305 STREG %r2,TASK_PT_SR0(%r1) 306 mfsp %sr1,%r2 307 STREG %r2,TASK_PT_SR1(%r1) 308 mfsp %sr2,%r2 309 STREG %r2,TASK_PT_SR2(%r1) 310 mfsp %sr3,%r2 311 STREG %r2,TASK_PT_SR3(%r1) 312 STREG %r2,TASK_PT_SR4(%r1) 313 STREG %r2,TASK_PT_SR5(%r1) 314 STREG %r2,TASK_PT_SR6(%r1) 315 STREG %r2,TASK_PT_SR7(%r1) 316 STREG %r2,TASK_PT_IASQ0(%r1) 317 STREG %r2,TASK_PT_IASQ1(%r1) 318 LDREG TASK_PT_GR31(%r1),%r2 319 STREG %r2,TASK_PT_IAOQ0(%r1) 320 ldo 4(%r2),%r2 321 STREG %r2,TASK_PT_IAOQ1(%r1) 322 ldo TASK_REGS(%r1),%r2 323 /* reg_save %r2 */ 324 STREG %r3,PT_GR3(%r2) 325 STREG %r4,PT_GR4(%r2) 326 STREG %r5,PT_GR5(%r2) 327 STREG %r6,PT_GR6(%r2) 328 STREG %r7,PT_GR7(%r2) 329 STREG %r8,PT_GR8(%r2) 330 STREG %r9,PT_GR9(%r2) 331 STREG %r10,PT_GR10(%r2) 332 STREG %r11,PT_GR11(%r2) 333 STREG %r12,PT_GR12(%r2) 334 STREG %r13,PT_GR13(%r2) 335 STREG %r14,PT_GR14(%r2) 336 STREG %r15,PT_GR15(%r2) 337 STREG %r16,PT_GR16(%r2) 338 STREG %r17,PT_GR17(%r2) 339 STREG %r18,PT_GR18(%r2) 340 /* Finished saving things for the debugger */ 341 342 copy %r2,%r26 343 ldil L%do_syscall_trace_enter,%r1 344 ldil L%tracesys_next,%r2 345 be R%do_syscall_trace_enter(%sr7,%r1) 346 ldo R%tracesys_next(%r2),%r2 347 348tracesys_next: 349 /* do_syscall_trace_enter either returned the syscallno, or -1L, 350 * so we skip restoring the PT_GR20 below, since we pulled it from 351 * task->thread.regs.gr[20] above. 352 */ 353 copy %ret0,%r20 354 355 mfctl %cr30,%r1 /* get task ptr */ 356 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return value */ 357 LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 358 LDREG TASK_PT_GR25(%r1), %r25 359 LDREG TASK_PT_GR24(%r1), %r24 360 LDREG TASK_PT_GR23(%r1), %r23 361 LDREG TASK_PT_GR22(%r1), %r22 362 LDREG TASK_PT_GR21(%r1), %r21 363#ifdef CONFIG_64BIT 364 ldo -16(%r30),%r29 /* Reference param save area */ 365#else 366 stw %r22, -52(%r30) /* 5th argument */ 367 stw %r21, -56(%r30) /* 6th argument */ 368#endif 369 370 cmpib,COND(=),n -1,%r20,tracesys_exit /* seccomp may have returned -1 */ 371 comiclr,>> __NR_Linux_syscalls, %r20, %r0 372 b,n .Ltracesys_nosys 373 374 /* Note! We cannot use the syscall table that is mapped 375 nearby since the gateway page is mapped execute-only. */ 376 377#ifdef CONFIG_64BIT 378 LDREG TASK_PT_GR30(%r1), %r19 /* get users sp back */ 379 extrd,u %r19,63,1,%r2 /* W hidden in bottom bit */ 380 381 ldil L%sys_call_table, %r1 382 or,ev %r2,%r2,%r2 383 ldil L%sys_call_table64, %r1 384 ldo R%sys_call_table(%r1), %r19 385 or,ev %r2,%r2,%r2 386 ldo R%sys_call_table64(%r1), %r19 387#else 388 load32 sys_call_table, %r19 389#endif 390 391 LDREGX %r20(%r19), %r19 392 393 /* If this is a sys_rt_sigreturn call, and the signal was received 394 * when not in_syscall, then we want to return via syscall_exit_rfi, 395 * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 396 * trampoline code in signal.c). 397 */ 398 ldi __NR_rt_sigreturn,%r2 399 comb,= %r2,%r20,.Ltrace_rt_sigreturn 400.Ltrace_in_syscall: 401 ldil L%tracesys_exit,%r2 402 be 0(%sr7,%r19) 403 ldo R%tracesys_exit(%r2),%r2 404 405.Ltracesys_nosys: 406 ldo -ENOSYS(%r0),%r28 /* set errno */ 407 408 /* Do *not* call this function on the gateway page, because it 409 makes a direct call to syscall_trace. */ 410 411tracesys_exit: 412 mfctl %cr30,%r1 /* get task ptr */ 413#ifdef CONFIG_64BIT 414 ldo -16(%r30),%r29 /* Reference param save area */ 415#endif 416 ldo TASK_REGS(%r1),%r26 417 BL do_syscall_trace_exit,%r2 418 STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 419 mfctl %cr30,%r1 /* get task ptr */ 420 LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 421 422 ldil L%syscall_exit,%r1 423 be,n R%syscall_exit(%sr7,%r1) 424 425.Ltrace_rt_sigreturn: 426 comib,<> 0,%r25,.Ltrace_in_syscall 427 ldil L%tracesys_sigexit,%r2 428 be 0(%sr7,%r19) 429 ldo R%tracesys_sigexit(%r2),%r2 430 431tracesys_sigexit: 432 mfctl %cr30,%r1 /* get task ptr */ 433#ifdef CONFIG_64BIT 434 ldo -16(%r30),%r29 /* Reference param save area */ 435#endif 436 BL do_syscall_trace_exit,%r2 437 ldo TASK_REGS(%r1),%r26 438 439 ldil L%syscall_exit_rfi,%r1 440 be,n R%syscall_exit_rfi(%sr7,%r1) 441 442 443 /********************************************************* 444 32/64-bit Light-Weight-Syscall ABI 445 446 * - Indicates a hint for userspace inline asm 447 implementations. 448 449 Syscall number (caller-saves) 450 - %r20 451 * In asm clobber. 452 453 Argument registers (caller-saves) 454 - %r26, %r25, %r24, %r23, %r22 455 * In asm input. 456 457 Return registers (caller-saves) 458 - %r28 (return), %r21 (errno) 459 * In asm output. 460 461 Caller-saves registers 462 - %r1, %r27, %r29 463 - %r2 (return pointer) 464 - %r31 (ble link register) 465 * In asm clobber. 466 467 Callee-saves registers 468 - %r3-%r18 469 - %r30 (stack pointer) 470 * Not in asm clobber. 471 472 If userspace is 32-bit: 473 Callee-saves registers 474 - %r19 (32-bit PIC register) 475 476 Differences from 32-bit calling convention: 477 - Syscall number in %r20 478 - Additional argument register %r22 (arg4) 479 - Callee-saves %r19. 480 481 If userspace is 64-bit: 482 Callee-saves registers 483 - %r27 (64-bit PIC register) 484 485 Differences from 64-bit calling convention: 486 - Syscall number in %r20 487 - Additional argument register %r22 (arg4) 488 - Callee-saves %r27. 489 490 Error codes returned by entry path: 491 492 ENOSYS - r20 was an invalid LWS number. 493 494 *********************************************************/ 495lws_start: 496 497#ifdef CONFIG_64BIT 498 ssm PSW_SM_W, %r1 499 extrd,u %r1,PSW_W_BIT,1,%r1 500 /* sp must be aligned on 4, so deposit the W bit setting into 501 * the bottom of sp temporarily */ 502 or,od %r1,%r30,%r30 503 504 /* Clip LWS number to a 32-bit value for 32-bit processes */ 505 depdi 0, 31, 32, %r20 506#endif 507 508 /* Is the lws entry number valid? */ 509 comiclr,>> __NR_lws_entries, %r20, %r0 510 b,n lws_exit_nosys 511 512 /* Load table start */ 513 ldil L%lws_table, %r1 514 ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 515 LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 516 517 /* Jump to lws, lws table pointers already relocated */ 518 be,n 0(%sr2,%r21) 519 520lws_exit_noerror: 521 lws_pagefault_enable %r1,%r21 522 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, %r21 523 stw,ma %r21, 0(%sr2,%r20) 524 ssm PSW_SM_I, %r0 525 b lws_exit 526 copy %r0, %r21 527 528lws_wouldblock: 529 ssm PSW_SM_I, %r0 530 ldo 2(%r0), %r28 531 b lws_exit 532 ldo -EAGAIN(%r0), %r21 533 534lws_pagefault: 535 lws_pagefault_enable %r1,%r21 536 ldi __ARCH_SPIN_LOCK_UNLOCKED_VAL, %r21 537 stw,ma %r21, 0(%sr2,%r20) 538 ssm PSW_SM_I, %r0 539 ldo 3(%r0),%r28 540 b lws_exit 541 ldo -EAGAIN(%r0),%r21 542 543lws_fault: 544 ldo 1(%r0),%r28 545 b lws_exit 546 ldo -EFAULT(%r0),%r21 547 548lws_exit_nosys: 549 ldo -ENOSYS(%r0),%r21 550 /* Fall through: Return to userspace */ 551 552lws_exit: 553#ifdef CONFIG_64BIT 554 /* decide whether to reset the wide mode bit 555 * 556 * For a syscall, the W bit is stored in the lowest bit 557 * of sp. Extract it and reset W if it is zero */ 558 extrd,u,*<> %r30,63,1,%r1 559 rsm PSW_SM_W, %r0 560 /* now reset the lowest bit of sp if it was set */ 561 xor %r30,%r1,%r30 562#endif 563 be,n 0(%sr7, %r31) 564 565 566 567 /*************************************************** 568 Implementing 32bit CAS as an atomic operation: 569 570 %r26 - Address to examine 571 %r25 - Old value to check (old) 572 %r24 - New value to set (new) 573 %r28 - Return prev through this register. 574 %r21 - Kernel error code 575 576 %r21 returns the following error codes: 577 EAGAIN - CAS is busy, ldcw failed, try again. 578 EFAULT - Read or write failed. 579 580 If EAGAIN is returned, %r28 indicates the busy reason: 581 r28 == 1 - CAS is busy. lock contended. 582 r28 == 2 - CAS is busy. ldcw failed. 583 r28 == 3 - CAS is busy. page fault. 584 585 Scratch: r20, r28, r1 586 587 ****************************************************/ 588 589 /* ELF64 Process entry path */ 590lws_compare_and_swap64: 591#ifdef CONFIG_64BIT 592 b,n lws_compare_and_swap 593#else 594 /* If we are not a 64-bit kernel, then we don't 595 * have 64-bit input registers, and calling 596 * the 64-bit LWS CAS returns ENOSYS. 597 */ 598 b,n lws_exit_nosys 599#endif 600 601 /* ELF32/ELF64 Process entry path */ 602lws_compare_and_swap32: 603#ifdef CONFIG_64BIT 604 /* Wide mode user process? */ 605 bb,<,n %sp, 31, lws_compare_and_swap 606 607 /* Clip all the input registers for 32-bit processes */ 608 depdi 0, 31, 32, %r26 609 depdi 0, 31, 32, %r25 610 depdi 0, 31, 32, %r24 611#endif 612 613lws_compare_and_swap: 614 /* Trigger memory reference interruptions without writing to memory */ 6151: ldw 0(%r26), %r28 616 proberi (%r26), PRIV_USER, %r28 617 comb,=,n %r28, %r0, lws_fault /* backwards, likely not taken */ 618 nop 6192: stbys,e %r0, 0(%r26) 620 621 /* Calculate 8-bit hash index from virtual address */ 622 extru_safe %r26, 27, 8, %r20 623 624 /* Load start of lock table */ 625 ldil L%lws_lock_start, %r28 626 ldo R%lws_lock_start(%r28), %r28 627 628 /* Find lock to use, the hash index is one of 0 to 629 255, multiplied by 16 (keep it 16-byte aligned) 630 and add to the lock table offset. */ 631 shlw %r20, 4, %r20 632 add %r20, %r28, %r20 633 634 rsm PSW_SM_I, %r0 /* Disable interrupts */ 635 636 /* Try to acquire the lock */ 637 LDCW 0(%sr2,%r20), %r28 638 spinlock_check %r28, %r21 639 comclr,<> %r0, %r28, %r0 640 b,n lws_wouldblock 641 642 /* Disable page faults to prevent sleeping in critical region */ 643 lws_pagefault_disable %r21,%r28 644 645 /* 646 prev = *addr; 647 if ( prev == old ) 648 *addr = new; 649 return prev; 650 */ 651 652 /* NOTES: 653 This all works because intr_do_signal 654 and schedule both check the return iasq 655 and see that we are on the kernel page 656 so this process is never scheduled off 657 or is ever sent any signal of any sort, 658 thus it is wholly atomic from usrspace's 659 perspective 660 */ 661 /* The load and store could fail */ 6623: ldw 0(%r26), %r28 663 sub,<> %r28, %r25, %r0 6644: stw %r24, 0(%r26) 665 b,n lws_exit_noerror 666 667 /* A fault occurred on load or stbys,e store */ 6685: b,n lws_fault 669 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 5b-linux_gateway_page) 670 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 5b-linux_gateway_page) 671 672 /* A page fault occurred in critical region */ 6736: b,n lws_pagefault 674 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 6b-linux_gateway_page) 675 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 6b-linux_gateway_page) 676 677 678 /*************************************************** 679 New CAS implementation which uses pointers and variable size 680 information. The value pointed by old and new MUST NOT change 681 while performing CAS. The lock only protects the value at %r26. 682 683 %r26 - Address to examine 684 %r25 - Pointer to the value to check (old) 685 %r24 - Pointer to the value to set (new) 686 %r23 - Size of the variable (0/1/2/3 for 8/16/32/64 bit) 687 %r28 - Return non-zero on failure 688 %r21 - Kernel error code 689 690 %r21 returns the following error codes: 691 EAGAIN - CAS is busy, ldcw failed, try again. 692 EFAULT - Read or write failed. 693 694 If EAGAIN is returned, %r28 indicates the busy reason: 695 r28 == 1 - CAS is busy. lock contended. 696 r28 == 2 - CAS is busy. ldcw failed. 697 r28 == 3 - CAS is busy. page fault. 698 699 Scratch: r20, r22, r28, r29, r1, fr4 (32bit for 64bit CAS only) 700 701 ****************************************************/ 702 703lws_compare_and_swap_2: 704#ifdef CONFIG_64BIT 705 /* Wide mode user process? */ 706 bb,<,n %sp, 31, cas2_begin 707 708 /* Clip the input registers for 32-bit processes. We don't 709 need to clip %r23 as we only use it for word operations */ 710 depdi 0, 31, 32, %r26 711 depdi 0, 31, 32, %r25 712 depdi 0, 31, 32, %r24 713#endif 714 715cas2_begin: 716 /* Check the validity of the size pointer */ 717 subi,>>= 3, %r23, %r0 718 b,n lws_exit_nosys 719 720 /* Jump to the functions which will load the old and new values into 721 registers depending on the their size */ 722 shlw %r23, 2, %r29 723 blr %r29, %r0 724 nop 725 726 /* 8-bit load */ 7271: ldb 0(%r25), %r25 728 b cas2_lock_start 7292: ldb 0(%r24), %r24 730 nop 731 nop 732 nop 733 nop 734 nop 735 736 /* 16-bit load */ 7373: ldh 0(%r25), %r25 738 b cas2_lock_start 7394: ldh 0(%r24), %r24 740 nop 741 nop 742 nop 743 nop 744 nop 745 746 /* 32-bit load */ 7475: ldw 0(%r25), %r25 748 b cas2_lock_start 7496: ldw 0(%r24), %r24 750 nop 751 nop 752 nop 753 nop 754 nop 755 756 /* 64-bit load */ 757#ifdef CONFIG_64BIT 7587: ldd 0(%r25), %r25 7598: ldd 0(%r24), %r24 760#else 761 /* Load old value into r22/r23 - high/low */ 7627: ldw 0(%r25), %r22 7638: ldw 4(%r25), %r23 764 /* Load new value into fr4 for atomic store later */ 7659: flddx 0(%r24), %fr4 766#endif 767 768cas2_lock_start: 769 /* Trigger memory reference interruptions without writing to memory */ 770 copy %r26, %r28 771 depi_safe 0, 31, 2, %r28 77210: ldw 0(%r28), %r1 773 proberi (%r28), PRIV_USER, %r1 774 comb,=,n %r1, %r0, lws_fault /* backwards, likely not taken */ 775 nop 77611: stbys,e %r0, 0(%r28) 777 778 /* Calculate 8-bit hash index from virtual address */ 779 extru_safe %r26, 27, 8, %r20 780 781 /* Load start of lock table */ 782 ldil L%lws_lock_start, %r28 783 ldo R%lws_lock_start(%r28), %r28 784 785 /* Find lock to use, the hash index is one of 0 to 786 255, multiplied by 16 (keep it 16-byte aligned) 787 and add to the lock table offset. */ 788 shlw %r20, 4, %r20 789 add %r20, %r28, %r20 790 791 rsm PSW_SM_I, %r0 /* Disable interrupts */ 792 793 /* Try to acquire the lock */ 794 LDCW 0(%sr2,%r20), %r28 795 spinlock_check %r28, %r21 796 comclr,<> %r0, %r28, %r0 797 b,n lws_wouldblock 798 799 /* Disable page faults to prevent sleeping in critical region */ 800 lws_pagefault_disable %r21,%r28 801 802 /* 803 prev = *addr; 804 if ( prev == old ) 805 *addr = new; 806 return prev; 807 */ 808 809 /* NOTES: 810 This all works because intr_do_signal 811 and schedule both check the return iasq 812 and see that we are on the kernel page 813 so this process is never scheduled off 814 or is ever sent any signal of any sort, 815 thus it is wholly atomic from usrspace's 816 perspective 817 */ 818 819 /* Jump to the correct function */ 820 blr %r29, %r0 821 /* Set %r28 as non-zero for now */ 822 ldo 1(%r0),%r28 823 824 /* 8-bit CAS */ 82512: ldb 0(%r26), %r29 826 sub,= %r29, %r25, %r0 827 b,n lws_exit_noerror 82813: stb %r24, 0(%r26) 829 b lws_exit_noerror 830 copy %r0, %r28 831 nop 832 nop 833 834 /* 16-bit CAS */ 83514: ldh 0(%r26), %r29 836 sub,= %r29, %r25, %r0 837 b,n lws_exit_noerror 83815: sth %r24, 0(%r26) 839 b lws_exit_noerror 840 copy %r0, %r28 841 nop 842 nop 843 844 /* 32-bit CAS */ 84516: ldw 0(%r26), %r29 846 sub,= %r29, %r25, %r0 847 b,n lws_exit_noerror 84817: stw %r24, 0(%r26) 849 b lws_exit_noerror 850 copy %r0, %r28 851 nop 852 nop 853 854 /* 64-bit CAS */ 855#ifdef CONFIG_64BIT 85618: ldd 0(%r26), %r29 857 sub,*= %r29, %r25, %r0 858 b,n lws_exit_noerror 85919: std %r24, 0(%r26) 860 copy %r0, %r28 861#else 862 /* Compare first word */ 86318: ldw 0(%r26), %r29 864 sub,= %r29, %r22, %r0 865 b,n lws_exit_noerror 866 /* Compare second word */ 86719: ldw 4(%r26), %r29 868 sub,= %r29, %r23, %r0 869 b,n lws_exit_noerror 870 /* Perform the store */ 87120: fstdx %fr4, 0(%r26) 872 copy %r0, %r28 873#endif 874 b lws_exit_noerror 875 copy %r0, %r28 876 877 /* A fault occurred on load or stbys,e store */ 87830: b,n lws_fault 879 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page) 880 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page) 881 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page) 882 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page) 883 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page) 884 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page) 885 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page) 886 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 30b-linux_gateway_page) 887#ifndef CONFIG_64BIT 888 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 30b-linux_gateway_page) 889#endif 890 891 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 30b-linux_gateway_page) 892 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 30b-linux_gateway_page) 893 894 /* A page fault occurred in critical region */ 89531: b,n lws_pagefault 896 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 31b-linux_gateway_page) 897 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 31b-linux_gateway_page) 898 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page) 899 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page) 900 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page) 901 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 31b-linux_gateway_page) 902 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 31b-linux_gateway_page) 903 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 31b-linux_gateway_page) 904#ifndef CONFIG_64BIT 905 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 31b-linux_gateway_page) 906#endif 907 908 909 /*************************************************** 910 LWS atomic exchange. 911 912 %r26 - Exchange address 913 %r25 - Size of the variable (0/1/2/3 for 8/16/32/64 bit) 914 %r24 - Address of new value 915 %r23 - Address of old value 916 %r28 - Return non-zero on failure 917 %r21 - Kernel error code 918 919 %r21 returns the following error codes: 920 EAGAIN - CAS is busy, ldcw failed, try again. 921 EFAULT - Read or write failed. 922 923 If EAGAIN is returned, %r28 indicates the busy reason: 924 r28 == 1 - CAS is busy. lock contended. 925 r28 == 2 - CAS is busy. ldcw failed. 926 r28 == 3 - CAS is busy. page fault. 927 928 Scratch: r20, r1 929 930 ****************************************************/ 931 932lws_atomic_xchg: 933#ifdef CONFIG_64BIT 934 /* Wide mode user process? */ 935 bb,<,n %sp, 31, atomic_xchg_begin 936 937 /* Clip the input registers for 32-bit processes. We don't 938 need to clip %r23 as we only use it for word operations */ 939 depdi 0, 31, 32, %r26 940 depdi 0, 31, 32, %r25 941 depdi 0, 31, 32, %r24 942 depdi 0, 31, 32, %r23 943#endif 944 945atomic_xchg_begin: 946 /* Check the validity of the size pointer */ 947 subi,>>= 3, %r25, %r0 948 b,n lws_exit_nosys 949 950 /* Jump to the functions which will load the old and new values into 951 registers depending on the their size */ 952 shlw %r25, 2, %r1 953 blr %r1, %r0 954 nop 955 956 /* Perform exception checks */ 957 958 /* 8-bit exchange */ 9591: ldb 0(%r24), %r20 960 proberi (%r24), PRIV_USER, %r20 961 comb,=,n %r20, %r0, lws_fault /* backwards, likely not taken */ 962 nop 963 copy %r23, %r20 964 depi_safe 0, 31, 2, %r20 965 b atomic_xchg_start 9662: stbys,e %r0, 0(%r20) 967 968 /* 16-bit exchange */ 9693: ldh 0(%r24), %r20 970 proberi (%r24), PRIV_USER, %r20 971 comb,=,n %r20, %r0, lws_fault /* backwards, likely not taken */ 972 nop 973 copy %r23, %r20 974 depi_safe 0, 31, 2, %r20 975 b atomic_xchg_start 9764: stbys,e %r0, 0(%r20) 977 978 /* 32-bit exchange */ 9795: ldw 0(%r24), %r20 980 proberi (%r24), PRIV_USER, %r20 981 comb,=,n %r20, %r0, lws_fault /* backwards, likely not taken */ 982 nop 983 b atomic_xchg_start 9846: stbys,e %r0, 0(%r23) 985 nop 986 nop 987 988 /* 64-bit exchange */ 989#ifdef CONFIG_64BIT 9907: ldd 0(%r24), %r20 991 proberi (%r24), PRIV_USER, %r20 992 comb,=,n %r20, %r0, lws_fault /* backwards, likely not taken */ 993 nop 9948: stdby,e %r0, 0(%r23) 995#else 9967: ldw 0(%r24), %r20 9978: ldw 4(%r24), %r20 998 proberi (%r24), PRIV_USER, %r20 999 comb,=,n %r20, %r0, lws_fault /* backwards, likely not taken */ 1000 nop 1001 copy %r23, %r20 1002 depi_safe 0, 31, 2, %r20 10039: stbys,e %r0, 0(%r20) 100410: stbys,e %r0, 4(%r20) 1005#endif 1006 1007atomic_xchg_start: 1008 /* Trigger memory reference interruptions without writing to memory */ 1009 copy %r26, %r28 1010 depi_safe 0, 31, 2, %r28 101111: ldw 0(%r28), %r1 101212: stbys,e %r0, 0(%r28) 1013 1014 /* Calculate 8-bit hash index from virtual address */ 1015 extru_safe %r26, 27, 8, %r20 1016 1017 /* Load start of lock table */ 1018 ldil L%lws_lock_start, %r28 1019 ldo R%lws_lock_start(%r28), %r28 1020 1021 /* Find lock to use, the hash index is one of 0 to 1022 255, multiplied by 16 (keep it 16-byte aligned) 1023 and add to the lock table offset. */ 1024 shlw %r20, 4, %r20 1025 add %r20, %r28, %r20 1026 1027 rsm PSW_SM_I, %r0 /* Disable interrupts */ 1028 1029 /* Try to acquire the lock */ 1030 LDCW 0(%sr2,%r20), %r28 1031 spinlock_check %r28, %r21 1032 comclr,<> %r0, %r28, %r0 1033 b,n lws_wouldblock 1034 1035 /* Disable page faults to prevent sleeping in critical region */ 1036 lws_pagefault_disable %r21,%r28 1037 1038 /* NOTES: 1039 This all works because intr_do_signal 1040 and schedule both check the return iasq 1041 and see that we are on the kernel page 1042 so this process is never scheduled off 1043 or is ever sent any signal of any sort, 1044 thus it is wholly atomic from userspace's 1045 perspective 1046 */ 1047 1048 /* Jump to the correct function */ 1049 blr %r1, %r0 1050 /* Set %r28 as non-zero for now */ 1051 ldo 1(%r0),%r28 1052 1053 /* 8-bit exchange */ 105414: ldb 0(%r26), %r1 105515: stb %r1, 0(%r23) 105615: ldb 0(%r24), %r1 105717: stb %r1, 0(%r26) 1058 b lws_exit_noerror 1059 copy %r0, %r28 1060 nop 1061 nop 1062 1063 /* 16-bit exchange */ 106418: ldh 0(%r26), %r1 106519: sth %r1, 0(%r23) 106620: ldh 0(%r24), %r1 106721: sth %r1, 0(%r26) 1068 b lws_exit_noerror 1069 copy %r0, %r28 1070 nop 1071 nop 1072 1073 /* 32-bit exchange */ 107422: ldw 0(%r26), %r1 107523: stw %r1, 0(%r23) 107624: ldw 0(%r24), %r1 107725: stw %r1, 0(%r26) 1078 b lws_exit_noerror 1079 copy %r0, %r28 1080 nop 1081 nop 1082 1083 /* 64-bit exchange */ 1084#ifdef CONFIG_64BIT 108526: ldd 0(%r26), %r1 108627: std %r1, 0(%r23) 108728: ldd 0(%r24), %r1 108829: std %r1, 0(%r26) 1089#else 109026: flddx 0(%r26), %fr4 109127: fstdx %fr4, 0(%r23) 109228: flddx 0(%r24), %fr4 109329: fstdx %fr4, 0(%r26) 1094#endif 1095 b lws_exit_noerror 1096 copy %r0, %r28 1097 1098 /* A fault occurred on load or stbys,e store */ 109930: b,n lws_fault 1100 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page) 1101 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page) 1102 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page) 1103 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page) 1104 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page) 1105 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page) 1106 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page) 1107 ASM_EXCEPTIONTABLE_ENTRY(8b-linux_gateway_page, 30b-linux_gateway_page) 1108#ifndef CONFIG_64BIT 1109 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 30b-linux_gateway_page) 1110 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 30b-linux_gateway_page) 1111#endif 1112 1113 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 30b-linux_gateway_page) 1114 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 30b-linux_gateway_page) 1115 1116 /* A page fault occurred in critical region */ 111731: b,n lws_pagefault 1118 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page) 1119 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page) 1120 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page) 1121 ASM_EXCEPTIONTABLE_ENTRY(17b-linux_gateway_page, 31b-linux_gateway_page) 1122 ASM_EXCEPTIONTABLE_ENTRY(18b-linux_gateway_page, 31b-linux_gateway_page) 1123 ASM_EXCEPTIONTABLE_ENTRY(19b-linux_gateway_page, 31b-linux_gateway_page) 1124 ASM_EXCEPTIONTABLE_ENTRY(20b-linux_gateway_page, 31b-linux_gateway_page) 1125 ASM_EXCEPTIONTABLE_ENTRY(21b-linux_gateway_page, 31b-linux_gateway_page) 1126 ASM_EXCEPTIONTABLE_ENTRY(22b-linux_gateway_page, 31b-linux_gateway_page) 1127 ASM_EXCEPTIONTABLE_ENTRY(23b-linux_gateway_page, 31b-linux_gateway_page) 1128 ASM_EXCEPTIONTABLE_ENTRY(24b-linux_gateway_page, 31b-linux_gateway_page) 1129 ASM_EXCEPTIONTABLE_ENTRY(25b-linux_gateway_page, 31b-linux_gateway_page) 1130 ASM_EXCEPTIONTABLE_ENTRY(26b-linux_gateway_page, 31b-linux_gateway_page) 1131 ASM_EXCEPTIONTABLE_ENTRY(27b-linux_gateway_page, 31b-linux_gateway_page) 1132 ASM_EXCEPTIONTABLE_ENTRY(28b-linux_gateway_page, 31b-linux_gateway_page) 1133 ASM_EXCEPTIONTABLE_ENTRY(29b-linux_gateway_page, 31b-linux_gateway_page) 1134 1135 /*************************************************** 1136 LWS atomic store. 1137 1138 %r26 - Address to store 1139 %r25 - Size of the variable (0/1/2/3 for 8/16/32/64 bit) 1140 %r24 - Address of value to store 1141 %r28 - Return non-zero on failure 1142 %r21 - Kernel error code 1143 1144 %r21 returns the following error codes: 1145 EAGAIN - CAS is busy, ldcw failed, try again. 1146 EFAULT - Read or write failed. 1147 1148 If EAGAIN is returned, %r28 indicates the busy reason: 1149 r28 == 1 - CAS is busy. lock contended. 1150 r28 == 2 - CAS is busy. ldcw failed. 1151 r28 == 3 - CAS is busy. page fault. 1152 1153 Scratch: r20, r1 1154 1155 ****************************************************/ 1156 1157lws_atomic_store: 1158#ifdef CONFIG_64BIT 1159 /* Wide mode user process? */ 1160 bb,<,n %sp, 31, atomic_store_begin 1161 1162 /* Clip the input registers for 32-bit processes. We don't 1163 need to clip %r23 as we only use it for word operations */ 1164 depdi 0, 31, 32, %r26 1165 depdi 0, 31, 32, %r25 1166 depdi 0, 31, 32, %r24 1167#endif 1168 1169atomic_store_begin: 1170 /* Check the validity of the size pointer */ 1171 subi,>>= 3, %r25, %r0 1172 b,n lws_exit_nosys 1173 1174 shlw %r25, 1, %r1 1175 blr %r1, %r0 1176 nop 1177 1178 /* Perform exception checks */ 1179 1180 /* 8-bit store */ 11811: ldb 0(%r24), %r20 1182 b,n atomic_store_start 1183 nop 1184 nop 1185 1186 /* 16-bit store */ 11872: ldh 0(%r24), %r20 1188 b,n atomic_store_start 1189 nop 1190 nop 1191 1192 /* 32-bit store */ 11933: ldw 0(%r24), %r20 1194 b,n atomic_store_start 1195 nop 1196 nop 1197 1198 /* 64-bit store */ 1199#ifdef CONFIG_64BIT 12004: ldd 0(%r24), %r20 1201#else 12024: ldw 0(%r24), %r20 12035: ldw 4(%r24), %r20 1204#endif 1205 1206atomic_store_start: 1207 /* Trigger memory reference interruptions without writing to memory */ 1208 copy %r26, %r28 1209 depi_safe 0, 31, 2, %r28 12106: ldw 0(%r28), %r1 12117: stbys,e %r0, 0(%r28) 1212 1213 /* Calculate 8-bit hash index from virtual address */ 1214 extru_safe %r26, 27, 8, %r20 1215 1216 /* Load start of lock table */ 1217 ldil L%lws_lock_start, %r28 1218 ldo R%lws_lock_start(%r28), %r28 1219 1220 /* Find lock to use, the hash index is one of 0 to 1221 255, multiplied by 16 (keep it 16-byte aligned) 1222 and add to the lock table offset. */ 1223 shlw %r20, 4, %r20 1224 add %r20, %r28, %r20 1225 1226 rsm PSW_SM_I, %r0 /* Disable interrupts */ 1227 1228 /* Try to acquire the lock */ 1229 LDCW 0(%sr2,%r20), %r28 1230 spinlock_check %r28, %r21 1231 comclr,<> %r0, %r28, %r0 1232 b,n lws_wouldblock 1233 1234 /* Disable page faults to prevent sleeping in critical region */ 1235 lws_pagefault_disable %r21,%r28 1236 1237 /* NOTES: 1238 This all works because intr_do_signal 1239 and schedule both check the return iasq 1240 and see that we are on the kernel page 1241 so this process is never scheduled off 1242 or is ever sent any signal of any sort, 1243 thus it is wholly atomic from userspace's 1244 perspective 1245 */ 1246 1247 /* Jump to the correct function */ 1248 blr %r1, %r0 1249 /* Set %r28 as non-zero for now */ 1250 ldo 1(%r0),%r28 1251 1252 /* 8-bit store */ 12539: ldb 0(%r24), %r1 125410: stb %r1, 0(%r26) 1255 b lws_exit_noerror 1256 copy %r0, %r28 1257 1258 /* 16-bit store */ 125911: ldh 0(%r24), %r1 126012: sth %r1, 0(%r26) 1261 b lws_exit_noerror 1262 copy %r0, %r28 1263 1264 /* 32-bit store */ 126513: ldw 0(%r24), %r1 126614: stw %r1, 0(%r26) 1267 b lws_exit_noerror 1268 copy %r0, %r28 1269 1270 /* 64-bit store */ 1271#ifdef CONFIG_64BIT 127215: ldd 0(%r24), %r1 127316: std %r1, 0(%r26) 1274#else 127515: flddx 0(%r24), %fr4 127616: fstdx %fr4, 0(%r26) 1277#endif 1278 b lws_exit_noerror 1279 copy %r0, %r28 1280 1281 /* A fault occurred on load or stbys,e store */ 128230: b,n lws_fault 1283 ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 30b-linux_gateway_page) 1284 ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 30b-linux_gateway_page) 1285 ASM_EXCEPTIONTABLE_ENTRY(3b-linux_gateway_page, 30b-linux_gateway_page) 1286 ASM_EXCEPTIONTABLE_ENTRY(4b-linux_gateway_page, 30b-linux_gateway_page) 1287#ifndef CONFIG_64BIT 1288 ASM_EXCEPTIONTABLE_ENTRY(5b-linux_gateway_page, 30b-linux_gateway_page) 1289#endif 1290 1291 ASM_EXCEPTIONTABLE_ENTRY(6b-linux_gateway_page, 30b-linux_gateway_page) 1292 ASM_EXCEPTIONTABLE_ENTRY(7b-linux_gateway_page, 30b-linux_gateway_page) 1293 1294 /* A page fault occurred in critical region */ 129531: b,n lws_pagefault 1296 ASM_EXCEPTIONTABLE_ENTRY(9b-linux_gateway_page, 31b-linux_gateway_page) 1297 ASM_EXCEPTIONTABLE_ENTRY(10b-linux_gateway_page, 31b-linux_gateway_page) 1298 ASM_EXCEPTIONTABLE_ENTRY(11b-linux_gateway_page, 31b-linux_gateway_page) 1299 ASM_EXCEPTIONTABLE_ENTRY(12b-linux_gateway_page, 31b-linux_gateway_page) 1300 ASM_EXCEPTIONTABLE_ENTRY(13b-linux_gateway_page, 31b-linux_gateway_page) 1301 ASM_EXCEPTIONTABLE_ENTRY(14b-linux_gateway_page, 31b-linux_gateway_page) 1302 ASM_EXCEPTIONTABLE_ENTRY(15b-linux_gateway_page, 31b-linux_gateway_page) 1303 ASM_EXCEPTIONTABLE_ENTRY(16b-linux_gateway_page, 31b-linux_gateway_page) 1304 1305 /* Make sure nothing else is placed on this page */ 1306 .align PAGE_SIZE 1307END(linux_gateway_page) 1308ENTRY(end_linux_gateway_page) 1309 1310 /* Relocate symbols assuming linux_gateway_page is mapped 1311 to virtual address 0x0 */ 1312 1313#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 1314 1315 .section .rodata,"a" 1316 1317 .align 8 1318 /* Light-weight-syscall table */ 1319 /* Start of lws table. */ 1320ENTRY(lws_table) 1321 LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic 32bit CAS */ 1322 LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic 32bit CAS */ 1323 LWS_ENTRY(compare_and_swap_2) /* 2 - Atomic 64bit CAS */ 1324 LWS_ENTRY(atomic_xchg) /* 3 - Atomic Exchange */ 1325 LWS_ENTRY(atomic_store) /* 4 - Atomic Store */ 1326END(lws_table) 1327 /* End of lws table */ 1328 1329#ifdef CONFIG_64BIT 1330#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat) 1331#else 1332#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native) 1333#endif 1334#define __SYSCALL(nr, entry) ASM_ULONG_INSN entry 1335 .align 8 1336ENTRY(sys_call_table) 1337 .export sys_call_table,data 1338#include <asm/syscall_table_32.h> /* 32-bit syscalls */ 1339END(sys_call_table) 1340 1341#ifdef CONFIG_64BIT 1342#undef __SYSCALL_WITH_COMPAT 1343#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native) 1344 .align 8 1345ENTRY(sys_call_table64) 1346#include <asm/syscall_table_64.h> /* 64-bit syscalls */ 1347END(sys_call_table64) 1348#endif 1349 1350 /* 1351 All light-weight-syscall atomic operations 1352 will use this set of locks 1353 1354 NOTE: The lws_lock_start symbol must be 1355 at least 16-byte aligned for safe use 1356 with ldcw. 1357 */ 1358 .section .data 1359 .align L1_CACHE_BYTES 1360ENTRY(lws_lock_start) 1361 /* lws locks */ 1362 .rept 256 1363 /* Keep locks aligned at 16-bytes */ 1364 .word __ARCH_SPIN_LOCK_UNLOCKED_VAL 1365 .word 0 1366 .word 0 1367 .word 0 1368 .endr 1369END(lws_lock_start) 1370 .previous 1371 1372.end 1373