1 /* 2 * Derived from "arch/i386/kernel/process.c" 3 * Copyright (C) 1995 Linus Torvalds 4 * 5 * Updated and modified by Cort Dougan (cort@cs.nmt.edu) and 6 * Paul Mackerras (paulus@cs.anu.edu.au) 7 * 8 * PowerPC version 9 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 */ 16 17 #include <linux/errno.h> 18 #include <linux/sched.h> 19 #include <linux/kernel.h> 20 #include <linux/mm.h> 21 #include <linux/smp.h> 22 #include <linux/stddef.h> 23 #include <linux/unistd.h> 24 #include <linux/ptrace.h> 25 #include <linux/slab.h> 26 #include <linux/user.h> 27 #include <linux/elf.h> 28 #include <linux/init.h> 29 #include <linux/prctl.h> 30 #include <linux/init_task.h> 31 #include <linux/export.h> 32 #include <linux/kallsyms.h> 33 #include <linux/mqueue.h> 34 #include <linux/hardirq.h> 35 #include <linux/utsname.h> 36 #include <linux/ftrace.h> 37 #include <linux/kernel_stat.h> 38 #include <linux/personality.h> 39 #include <linux/random.h> 40 #include <linux/hw_breakpoint.h> 41 42 #include <asm/pgtable.h> 43 #include <asm/uaccess.h> 44 #include <asm/io.h> 45 #include <asm/processor.h> 46 #include <asm/mmu.h> 47 #include <asm/prom.h> 48 #include <asm/machdep.h> 49 #include <asm/time.h> 50 #include <asm/runlatch.h> 51 #include <asm/syscalls.h> 52 #include <asm/switch_to.h> 53 #include <asm/debug.h> 54 #ifdef CONFIG_PPC64 55 #include <asm/firmware.h> 56 #endif 57 #include <linux/kprobes.h> 58 #include <linux/kdebug.h> 59 60 extern unsigned long _get_SP(void); 61 62 #ifndef CONFIG_SMP 63 struct task_struct *last_task_used_math = NULL; 64 struct task_struct *last_task_used_altivec = NULL; 65 struct task_struct *last_task_used_vsx = NULL; 66 struct task_struct *last_task_used_spe = NULL; 67 #endif 68 69 /* 70 * Make sure the floating-point register state in the 71 * the thread_struct is up to date for task tsk. 72 */ 73 void flush_fp_to_thread(struct task_struct *tsk) 74 { 75 if (tsk->thread.regs) { 76 /* 77 * We need to disable preemption here because if we didn't, 78 * another process could get scheduled after the regs->msr 79 * test but before we have finished saving the FP registers 80 * to the thread_struct. That process could take over the 81 * FPU, and then when we get scheduled again we would store 82 * bogus values for the remaining FP registers. 83 */ 84 preempt_disable(); 85 if (tsk->thread.regs->msr & MSR_FP) { 86 #ifdef CONFIG_SMP 87 /* 88 * This should only ever be called for current or 89 * for a stopped child process. Since we save away 90 * the FP register state on context switch on SMP, 91 * there is something wrong if a stopped child appears 92 * to still have its FP state in the CPU registers. 93 */ 94 BUG_ON(tsk != current); 95 #endif 96 giveup_fpu(tsk); 97 } 98 preempt_enable(); 99 } 100 } 101 EXPORT_SYMBOL_GPL(flush_fp_to_thread); 102 103 void enable_kernel_fp(void) 104 { 105 WARN_ON(preemptible()); 106 107 #ifdef CONFIG_SMP 108 if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) 109 giveup_fpu(current); 110 else 111 giveup_fpu(NULL); /* just enables FP for kernel */ 112 #else 113 giveup_fpu(last_task_used_math); 114 #endif /* CONFIG_SMP */ 115 } 116 EXPORT_SYMBOL(enable_kernel_fp); 117 118 #ifdef CONFIG_ALTIVEC 119 void enable_kernel_altivec(void) 120 { 121 WARN_ON(preemptible()); 122 123 #ifdef CONFIG_SMP 124 if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) 125 giveup_altivec(current); 126 else 127 giveup_altivec(NULL); /* just enable AltiVec for kernel - force */ 128 #else 129 giveup_altivec(last_task_used_altivec); 130 #endif /* CONFIG_SMP */ 131 } 132 EXPORT_SYMBOL(enable_kernel_altivec); 133 134 /* 135 * Make sure the VMX/Altivec register state in the 136 * the thread_struct is up to date for task tsk. 137 */ 138 void flush_altivec_to_thread(struct task_struct *tsk) 139 { 140 if (tsk->thread.regs) { 141 preempt_disable(); 142 if (tsk->thread.regs->msr & MSR_VEC) { 143 #ifdef CONFIG_SMP 144 BUG_ON(tsk != current); 145 #endif 146 giveup_altivec(tsk); 147 } 148 preempt_enable(); 149 } 150 } 151 EXPORT_SYMBOL_GPL(flush_altivec_to_thread); 152 #endif /* CONFIG_ALTIVEC */ 153 154 #ifdef CONFIG_VSX 155 #if 0 156 /* not currently used, but some crazy RAID module might want to later */ 157 void enable_kernel_vsx(void) 158 { 159 WARN_ON(preemptible()); 160 161 #ifdef CONFIG_SMP 162 if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) 163 giveup_vsx(current); 164 else 165 giveup_vsx(NULL); /* just enable vsx for kernel - force */ 166 #else 167 giveup_vsx(last_task_used_vsx); 168 #endif /* CONFIG_SMP */ 169 } 170 EXPORT_SYMBOL(enable_kernel_vsx); 171 #endif 172 173 void giveup_vsx(struct task_struct *tsk) 174 { 175 giveup_fpu(tsk); 176 giveup_altivec(tsk); 177 __giveup_vsx(tsk); 178 } 179 180 void flush_vsx_to_thread(struct task_struct *tsk) 181 { 182 if (tsk->thread.regs) { 183 preempt_disable(); 184 if (tsk->thread.regs->msr & MSR_VSX) { 185 #ifdef CONFIG_SMP 186 BUG_ON(tsk != current); 187 #endif 188 giveup_vsx(tsk); 189 } 190 preempt_enable(); 191 } 192 } 193 EXPORT_SYMBOL_GPL(flush_vsx_to_thread); 194 #endif /* CONFIG_VSX */ 195 196 #ifdef CONFIG_SPE 197 198 void enable_kernel_spe(void) 199 { 200 WARN_ON(preemptible()); 201 202 #ifdef CONFIG_SMP 203 if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) 204 giveup_spe(current); 205 else 206 giveup_spe(NULL); /* just enable SPE for kernel - force */ 207 #else 208 giveup_spe(last_task_used_spe); 209 #endif /* __SMP __ */ 210 } 211 EXPORT_SYMBOL(enable_kernel_spe); 212 213 void flush_spe_to_thread(struct task_struct *tsk) 214 { 215 if (tsk->thread.regs) { 216 preempt_disable(); 217 if (tsk->thread.regs->msr & MSR_SPE) { 218 #ifdef CONFIG_SMP 219 BUG_ON(tsk != current); 220 #endif 221 tsk->thread.spefscr = mfspr(SPRN_SPEFSCR); 222 giveup_spe(tsk); 223 } 224 preempt_enable(); 225 } 226 } 227 #endif /* CONFIG_SPE */ 228 229 #ifndef CONFIG_SMP 230 /* 231 * If we are doing lazy switching of CPU state (FP, altivec or SPE), 232 * and the current task has some state, discard it. 233 */ 234 void discard_lazy_cpu_state(void) 235 { 236 preempt_disable(); 237 if (last_task_used_math == current) 238 last_task_used_math = NULL; 239 #ifdef CONFIG_ALTIVEC 240 if (last_task_used_altivec == current) 241 last_task_used_altivec = NULL; 242 #endif /* CONFIG_ALTIVEC */ 243 #ifdef CONFIG_VSX 244 if (last_task_used_vsx == current) 245 last_task_used_vsx = NULL; 246 #endif /* CONFIG_VSX */ 247 #ifdef CONFIG_SPE 248 if (last_task_used_spe == current) 249 last_task_used_spe = NULL; 250 #endif 251 preempt_enable(); 252 } 253 #endif /* CONFIG_SMP */ 254 255 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 256 void do_send_trap(struct pt_regs *regs, unsigned long address, 257 unsigned long error_code, int signal_code, int breakpt) 258 { 259 siginfo_t info; 260 261 if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 262 11, SIGSEGV) == NOTIFY_STOP) 263 return; 264 265 /* Deliver the signal to userspace */ 266 info.si_signo = SIGTRAP; 267 info.si_errno = breakpt; /* breakpoint or watchpoint id */ 268 info.si_code = signal_code; 269 info.si_addr = (void __user *)address; 270 force_sig_info(SIGTRAP, &info, current); 271 } 272 #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ 273 void do_dabr(struct pt_regs *regs, unsigned long address, 274 unsigned long error_code) 275 { 276 siginfo_t info; 277 278 if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 279 11, SIGSEGV) == NOTIFY_STOP) 280 return; 281 282 if (debugger_dabr_match(regs)) 283 return; 284 285 /* Clear the DABR */ 286 set_dabr(0); 287 288 /* Deliver the signal to userspace */ 289 info.si_signo = SIGTRAP; 290 info.si_errno = 0; 291 info.si_code = TRAP_HWBKPT; 292 info.si_addr = (void __user *)address; 293 force_sig_info(SIGTRAP, &info, current); 294 } 295 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ 296 297 static DEFINE_PER_CPU(unsigned long, current_dabr); 298 299 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 300 /* 301 * Set the debug registers back to their default "safe" values. 302 */ 303 static void set_debug_reg_defaults(struct thread_struct *thread) 304 { 305 thread->iac1 = thread->iac2 = 0; 306 #if CONFIG_PPC_ADV_DEBUG_IACS > 2 307 thread->iac3 = thread->iac4 = 0; 308 #endif 309 thread->dac1 = thread->dac2 = 0; 310 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 311 thread->dvc1 = thread->dvc2 = 0; 312 #endif 313 thread->dbcr0 = 0; 314 #ifdef CONFIG_BOOKE 315 /* 316 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1) 317 */ 318 thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | \ 319 DBCR1_IAC3US | DBCR1_IAC4US; 320 /* 321 * Force Data Address Compare User/Supervisor bits to be User-only 322 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0. 323 */ 324 thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; 325 #else 326 thread->dbcr1 = 0; 327 #endif 328 } 329 330 static void prime_debug_regs(struct thread_struct *thread) 331 { 332 mtspr(SPRN_IAC1, thread->iac1); 333 mtspr(SPRN_IAC2, thread->iac2); 334 #if CONFIG_PPC_ADV_DEBUG_IACS > 2 335 mtspr(SPRN_IAC3, thread->iac3); 336 mtspr(SPRN_IAC4, thread->iac4); 337 #endif 338 mtspr(SPRN_DAC1, thread->dac1); 339 mtspr(SPRN_DAC2, thread->dac2); 340 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 341 mtspr(SPRN_DVC1, thread->dvc1); 342 mtspr(SPRN_DVC2, thread->dvc2); 343 #endif 344 mtspr(SPRN_DBCR0, thread->dbcr0); 345 mtspr(SPRN_DBCR1, thread->dbcr1); 346 #ifdef CONFIG_BOOKE 347 mtspr(SPRN_DBCR2, thread->dbcr2); 348 #endif 349 } 350 /* 351 * Unless neither the old or new thread are making use of the 352 * debug registers, set the debug registers from the values 353 * stored in the new thread. 354 */ 355 static void switch_booke_debug_regs(struct thread_struct *new_thread) 356 { 357 if ((current->thread.dbcr0 & DBCR0_IDM) 358 || (new_thread->dbcr0 & DBCR0_IDM)) 359 prime_debug_regs(new_thread); 360 } 361 #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ 362 #ifndef CONFIG_HAVE_HW_BREAKPOINT 363 static void set_debug_reg_defaults(struct thread_struct *thread) 364 { 365 if (thread->dabr) { 366 thread->dabr = 0; 367 set_dabr(0); 368 } 369 } 370 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */ 371 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ 372 373 int set_dabr(unsigned long dabr) 374 { 375 __get_cpu_var(current_dabr) = dabr; 376 377 if (ppc_md.set_dabr) 378 return ppc_md.set_dabr(dabr); 379 380 /* XXX should we have a CPU_FTR_HAS_DABR ? */ 381 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 382 mtspr(SPRN_DAC1, dabr); 383 #ifdef CONFIG_PPC_47x 384 isync(); 385 #endif 386 #elif defined(CONFIG_PPC_BOOK3S) 387 mtspr(SPRN_DABR, dabr); 388 #endif 389 390 391 return 0; 392 } 393 394 #ifdef CONFIG_PPC64 395 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array); 396 #endif 397 398 struct task_struct *__switch_to(struct task_struct *prev, 399 struct task_struct *new) 400 { 401 struct thread_struct *new_thread, *old_thread; 402 unsigned long flags; 403 struct task_struct *last; 404 #ifdef CONFIG_PPC_BOOK3S_64 405 struct ppc64_tlb_batch *batch; 406 #endif 407 408 #ifdef CONFIG_SMP 409 /* avoid complexity of lazy save/restore of fpu 410 * by just saving it every time we switch out if 411 * this task used the fpu during the last quantum. 412 * 413 * If it tries to use the fpu again, it'll trap and 414 * reload its fp regs. So we don't have to do a restore 415 * every switch, just a save. 416 * -- Cort 417 */ 418 if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP)) 419 giveup_fpu(prev); 420 #ifdef CONFIG_ALTIVEC 421 /* 422 * If the previous thread used altivec in the last quantum 423 * (thus changing altivec regs) then save them. 424 * We used to check the VRSAVE register but not all apps 425 * set it, so we don't rely on it now (and in fact we need 426 * to save & restore VSCR even if VRSAVE == 0). -- paulus 427 * 428 * On SMP we always save/restore altivec regs just to avoid the 429 * complexity of changing processors. 430 * -- Cort 431 */ 432 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)) 433 giveup_altivec(prev); 434 #endif /* CONFIG_ALTIVEC */ 435 #ifdef CONFIG_VSX 436 if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX)) 437 /* VMX and FPU registers are already save here */ 438 __giveup_vsx(prev); 439 #endif /* CONFIG_VSX */ 440 #ifdef CONFIG_SPE 441 /* 442 * If the previous thread used spe in the last quantum 443 * (thus changing spe regs) then save them. 444 * 445 * On SMP we always save/restore spe regs just to avoid the 446 * complexity of changing processors. 447 */ 448 if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE))) 449 giveup_spe(prev); 450 #endif /* CONFIG_SPE */ 451 452 #else /* CONFIG_SMP */ 453 #ifdef CONFIG_ALTIVEC 454 /* Avoid the trap. On smp this this never happens since 455 * we don't set last_task_used_altivec -- Cort 456 */ 457 if (new->thread.regs && last_task_used_altivec == new) 458 new->thread.regs->msr |= MSR_VEC; 459 #endif /* CONFIG_ALTIVEC */ 460 #ifdef CONFIG_VSX 461 if (new->thread.regs && last_task_used_vsx == new) 462 new->thread.regs->msr |= MSR_VSX; 463 #endif /* CONFIG_VSX */ 464 #ifdef CONFIG_SPE 465 /* Avoid the trap. On smp this this never happens since 466 * we don't set last_task_used_spe 467 */ 468 if (new->thread.regs && last_task_used_spe == new) 469 new->thread.regs->msr |= MSR_SPE; 470 #endif /* CONFIG_SPE */ 471 472 #endif /* CONFIG_SMP */ 473 474 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 475 switch_booke_debug_regs(&new->thread); 476 #else 477 /* 478 * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would 479 * schedule DABR 480 */ 481 #ifndef CONFIG_HAVE_HW_BREAKPOINT 482 if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) 483 set_dabr(new->thread.dabr); 484 #endif /* CONFIG_HAVE_HW_BREAKPOINT */ 485 #endif 486 487 488 new_thread = &new->thread; 489 old_thread = ¤t->thread; 490 491 #ifdef CONFIG_PPC64 492 /* 493 * Collect processor utilization data per process 494 */ 495 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 496 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 497 long unsigned start_tb, current_tb; 498 start_tb = old_thread->start_tb; 499 cu->current_tb = current_tb = mfspr(SPRN_PURR); 500 old_thread->accum_tb += (current_tb - start_tb); 501 new_thread->start_tb = current_tb; 502 } 503 #endif /* CONFIG_PPC64 */ 504 505 #ifdef CONFIG_PPC_BOOK3S_64 506 batch = &__get_cpu_var(ppc64_tlb_batch); 507 if (batch->active) { 508 current_thread_info()->local_flags |= _TLF_LAZY_MMU; 509 if (batch->index) 510 __flush_tlb_pending(batch); 511 batch->active = 0; 512 } 513 #endif /* CONFIG_PPC_BOOK3S_64 */ 514 515 local_irq_save(flags); 516 517 account_system_vtime(current); 518 account_process_vtime(current); 519 520 /* 521 * We can't take a PMU exception inside _switch() since there is a 522 * window where the kernel stack SLB and the kernel stack are out 523 * of sync. Hard disable here. 524 */ 525 hard_irq_disable(); 526 last = _switch(old_thread, new_thread); 527 528 #ifdef CONFIG_PPC_BOOK3S_64 529 if (current_thread_info()->local_flags & _TLF_LAZY_MMU) { 530 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU; 531 batch = &__get_cpu_var(ppc64_tlb_batch); 532 batch->active = 1; 533 } 534 #endif /* CONFIG_PPC_BOOK3S_64 */ 535 536 local_irq_restore(flags); 537 538 return last; 539 } 540 541 static int instructions_to_print = 16; 542 543 static void show_instructions(struct pt_regs *regs) 544 { 545 int i; 546 unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 * 547 sizeof(int)); 548 549 printk("Instruction dump:"); 550 551 for (i = 0; i < instructions_to_print; i++) { 552 int instr; 553 554 if (!(i % 8)) 555 printk("\n"); 556 557 #if !defined(CONFIG_BOOKE) 558 /* If executing with the IMMU off, adjust pc rather 559 * than print XXXXXXXX. 560 */ 561 if (!(regs->msr & MSR_IR)) 562 pc = (unsigned long)phys_to_virt(pc); 563 #endif 564 565 /* We use __get_user here *only* to avoid an OOPS on a 566 * bad address because the pc *should* only be a 567 * kernel address. 568 */ 569 if (!__kernel_text_address(pc) || 570 __get_user(instr, (unsigned int __user *)pc)) { 571 printk(KERN_CONT "XXXXXXXX "); 572 } else { 573 if (regs->nip == pc) 574 printk(KERN_CONT "<%08x> ", instr); 575 else 576 printk(KERN_CONT "%08x ", instr); 577 } 578 579 pc += sizeof(int); 580 } 581 582 printk("\n"); 583 } 584 585 static struct regbit { 586 unsigned long bit; 587 const char *name; 588 } msr_bits[] = { 589 #if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE) 590 {MSR_SF, "SF"}, 591 {MSR_HV, "HV"}, 592 #endif 593 {MSR_VEC, "VEC"}, 594 {MSR_VSX, "VSX"}, 595 #ifdef CONFIG_BOOKE 596 {MSR_CE, "CE"}, 597 #endif 598 {MSR_EE, "EE"}, 599 {MSR_PR, "PR"}, 600 {MSR_FP, "FP"}, 601 {MSR_ME, "ME"}, 602 #ifdef CONFIG_BOOKE 603 {MSR_DE, "DE"}, 604 #else 605 {MSR_SE, "SE"}, 606 {MSR_BE, "BE"}, 607 #endif 608 {MSR_IR, "IR"}, 609 {MSR_DR, "DR"}, 610 {MSR_PMM, "PMM"}, 611 #ifndef CONFIG_BOOKE 612 {MSR_RI, "RI"}, 613 {MSR_LE, "LE"}, 614 #endif 615 {0, NULL} 616 }; 617 618 static void printbits(unsigned long val, struct regbit *bits) 619 { 620 const char *sep = ""; 621 622 printk("<"); 623 for (; bits->bit; ++bits) 624 if (val & bits->bit) { 625 printk("%s%s", sep, bits->name); 626 sep = ","; 627 } 628 printk(">"); 629 } 630 631 #ifdef CONFIG_PPC64 632 #define REG "%016lx" 633 #define REGS_PER_LINE 4 634 #define LAST_VOLATILE 13 635 #else 636 #define REG "%08lx" 637 #define REGS_PER_LINE 8 638 #define LAST_VOLATILE 12 639 #endif 640 641 void show_regs(struct pt_regs * regs) 642 { 643 int i, trap; 644 645 printk("NIP: "REG" LR: "REG" CTR: "REG"\n", 646 regs->nip, regs->link, regs->ctr); 647 printk("REGS: %p TRAP: %04lx %s (%s)\n", 648 regs, regs->trap, print_tainted(), init_utsname()->release); 649 printk("MSR: "REG" ", regs->msr); 650 printbits(regs->msr, msr_bits); 651 printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); 652 #ifdef CONFIG_PPC64 653 printk("SOFTE: %ld\n", regs->softe); 654 #endif 655 trap = TRAP(regs); 656 if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR)) 657 printk("CFAR: "REG"\n", regs->orig_gpr3); 658 if (trap == 0x300 || trap == 0x600) 659 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) 660 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr); 661 #else 662 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr); 663 #endif 664 printk("TASK = %p[%d] '%s' THREAD: %p", 665 current, task_pid_nr(current), current->comm, task_thread_info(current)); 666 667 #ifdef CONFIG_SMP 668 printk(" CPU: %d", raw_smp_processor_id()); 669 #endif /* CONFIG_SMP */ 670 671 for (i = 0; i < 32; i++) { 672 if ((i % REGS_PER_LINE) == 0) 673 printk("\nGPR%02d: ", i); 674 printk(REG " ", regs->gpr[i]); 675 if (i == LAST_VOLATILE && !FULL_REGS(regs)) 676 break; 677 } 678 printk("\n"); 679 #ifdef CONFIG_KALLSYMS 680 /* 681 * Lookup NIP late so we have the best change of getting the 682 * above info out without failing 683 */ 684 printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip); 685 printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link); 686 #endif 687 show_stack(current, (unsigned long *) regs->gpr[1]); 688 if (!user_mode(regs)) 689 show_instructions(regs); 690 } 691 692 void exit_thread(void) 693 { 694 discard_lazy_cpu_state(); 695 } 696 697 void flush_thread(void) 698 { 699 discard_lazy_cpu_state(); 700 701 #ifdef CONFIG_HAVE_HW_BREAKPOINT 702 flush_ptrace_hw_breakpoint(current); 703 #else /* CONFIG_HAVE_HW_BREAKPOINT */ 704 set_debug_reg_defaults(¤t->thread); 705 #endif /* CONFIG_HAVE_HW_BREAKPOINT */ 706 } 707 708 void 709 release_thread(struct task_struct *t) 710 { 711 } 712 713 /* 714 * This gets called before we allocate a new thread and copy 715 * the current task into it. 716 */ 717 void prepare_to_copy(struct task_struct *tsk) 718 { 719 flush_fp_to_thread(current); 720 flush_altivec_to_thread(current); 721 flush_vsx_to_thread(current); 722 flush_spe_to_thread(current); 723 #ifdef CONFIG_HAVE_HW_BREAKPOINT 724 flush_ptrace_hw_breakpoint(tsk); 725 #endif /* CONFIG_HAVE_HW_BREAKPOINT */ 726 } 727 728 /* 729 * Copy a thread.. 730 */ 731 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */ 732 733 int copy_thread(unsigned long clone_flags, unsigned long usp, 734 unsigned long unused, struct task_struct *p, 735 struct pt_regs *regs) 736 { 737 struct pt_regs *childregs, *kregs; 738 extern void ret_from_fork(void); 739 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; 740 741 CHECK_FULL_REGS(regs); 742 /* Copy registers */ 743 sp -= sizeof(struct pt_regs); 744 childregs = (struct pt_regs *) sp; 745 *childregs = *regs; 746 if ((childregs->msr & MSR_PR) == 0) { 747 /* for kernel thread, set `current' and stackptr in new task */ 748 childregs->gpr[1] = sp + sizeof(struct pt_regs); 749 #ifdef CONFIG_PPC32 750 childregs->gpr[2] = (unsigned long) p; 751 #else 752 clear_tsk_thread_flag(p, TIF_32BIT); 753 #endif 754 p->thread.regs = NULL; /* no user register state */ 755 } else { 756 childregs->gpr[1] = usp; 757 p->thread.regs = childregs; 758 if (clone_flags & CLONE_SETTLS) { 759 #ifdef CONFIG_PPC64 760 if (!is_32bit_task()) 761 childregs->gpr[13] = childregs->gpr[6]; 762 else 763 #endif 764 childregs->gpr[2] = childregs->gpr[6]; 765 } 766 } 767 childregs->gpr[3] = 0; /* Result from fork() */ 768 sp -= STACK_FRAME_OVERHEAD; 769 770 /* 771 * The way this works is that at some point in the future 772 * some task will call _switch to switch to the new task. 773 * That will pop off the stack frame created below and start 774 * the new task running at ret_from_fork. The new task will 775 * do some house keeping and then return from the fork or clone 776 * system call, using the stack frame created above. 777 */ 778 sp -= sizeof(struct pt_regs); 779 kregs = (struct pt_regs *) sp; 780 sp -= STACK_FRAME_OVERHEAD; 781 p->thread.ksp = sp; 782 p->thread.ksp_limit = (unsigned long)task_stack_page(p) + 783 _ALIGN_UP(sizeof(struct thread_info), 16); 784 785 #ifdef CONFIG_PPC_STD_MMU_64 786 if (mmu_has_feature(MMU_FTR_SLB)) { 787 unsigned long sp_vsid; 788 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp; 789 790 if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) 791 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T) 792 << SLB_VSID_SHIFT_1T; 793 else 794 sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M) 795 << SLB_VSID_SHIFT; 796 sp_vsid |= SLB_VSID_KERNEL | llp; 797 p->thread.ksp_vsid = sp_vsid; 798 } 799 #endif /* CONFIG_PPC_STD_MMU_64 */ 800 #ifdef CONFIG_PPC64 801 if (cpu_has_feature(CPU_FTR_DSCR)) { 802 if (current->thread.dscr_inherit) { 803 p->thread.dscr_inherit = 1; 804 p->thread.dscr = current->thread.dscr; 805 } else if (0 != dscr_default) { 806 p->thread.dscr_inherit = 1; 807 p->thread.dscr = dscr_default; 808 } else { 809 p->thread.dscr_inherit = 0; 810 p->thread.dscr = 0; 811 } 812 } 813 #endif 814 815 /* 816 * The PPC64 ABI makes use of a TOC to contain function 817 * pointers. The function (ret_from_except) is actually a pointer 818 * to the TOC entry. The first entry is a pointer to the actual 819 * function. 820 */ 821 #ifdef CONFIG_PPC64 822 kregs->nip = *((unsigned long *)ret_from_fork); 823 #else 824 kregs->nip = (unsigned long)ret_from_fork; 825 #endif 826 827 return 0; 828 } 829 830 /* 831 * Set up a thread for executing a new program 832 */ 833 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) 834 { 835 #ifdef CONFIG_PPC64 836 unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */ 837 #endif 838 839 /* 840 * If we exec out of a kernel thread then thread.regs will not be 841 * set. Do it now. 842 */ 843 if (!current->thread.regs) { 844 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE; 845 current->thread.regs = regs - 1; 846 } 847 848 memset(regs->gpr, 0, sizeof(regs->gpr)); 849 regs->ctr = 0; 850 regs->link = 0; 851 regs->xer = 0; 852 regs->ccr = 0; 853 regs->gpr[1] = sp; 854 855 /* 856 * We have just cleared all the nonvolatile GPRs, so make 857 * FULL_REGS(regs) return true. This is necessary to allow 858 * ptrace to examine the thread immediately after exec. 859 */ 860 regs->trap &= ~1UL; 861 862 #ifdef CONFIG_PPC32 863 regs->mq = 0; 864 regs->nip = start; 865 regs->msr = MSR_USER; 866 #else 867 if (!is_32bit_task()) { 868 unsigned long entry, toc; 869 870 /* start is a relocated pointer to the function descriptor for 871 * the elf _start routine. The first entry in the function 872 * descriptor is the entry address of _start and the second 873 * entry is the TOC value we need to use. 874 */ 875 __get_user(entry, (unsigned long __user *)start); 876 __get_user(toc, (unsigned long __user *)start+1); 877 878 /* Check whether the e_entry function descriptor entries 879 * need to be relocated before we can use them. 880 */ 881 if (load_addr != 0) { 882 entry += load_addr; 883 toc += load_addr; 884 } 885 regs->nip = entry; 886 regs->gpr[2] = toc; 887 regs->msr = MSR_USER64; 888 } else { 889 regs->nip = start; 890 regs->gpr[2] = 0; 891 regs->msr = MSR_USER32; 892 } 893 #endif 894 895 discard_lazy_cpu_state(); 896 #ifdef CONFIG_VSX 897 current->thread.used_vsr = 0; 898 #endif 899 memset(current->thread.fpr, 0, sizeof(current->thread.fpr)); 900 current->thread.fpscr.val = 0; 901 #ifdef CONFIG_ALTIVEC 902 memset(current->thread.vr, 0, sizeof(current->thread.vr)); 903 memset(¤t->thread.vscr, 0, sizeof(current->thread.vscr)); 904 current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */ 905 current->thread.vrsave = 0; 906 current->thread.used_vr = 0; 907 #endif /* CONFIG_ALTIVEC */ 908 #ifdef CONFIG_SPE 909 memset(current->thread.evr, 0, sizeof(current->thread.evr)); 910 current->thread.acc = 0; 911 current->thread.spefscr = 0; 912 current->thread.used_spe = 0; 913 #endif /* CONFIG_SPE */ 914 } 915 916 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \ 917 | PR_FP_EXC_RES | PR_FP_EXC_INV) 918 919 int set_fpexc_mode(struct task_struct *tsk, unsigned int val) 920 { 921 struct pt_regs *regs = tsk->thread.regs; 922 923 /* This is a bit hairy. If we are an SPE enabled processor 924 * (have embedded fp) we store the IEEE exception enable flags in 925 * fpexc_mode. fpexc_mode is also used for setting FP exception 926 * mode (asyn, precise, disabled) for 'Classic' FP. */ 927 if (val & PR_FP_EXC_SW_ENABLE) { 928 #ifdef CONFIG_SPE 929 if (cpu_has_feature(CPU_FTR_SPE)) { 930 tsk->thread.fpexc_mode = val & 931 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT); 932 return 0; 933 } else { 934 return -EINVAL; 935 } 936 #else 937 return -EINVAL; 938 #endif 939 } 940 941 /* on a CONFIG_SPE this does not hurt us. The bits that 942 * __pack_fe01 use do not overlap with bits used for 943 * PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits 944 * on CONFIG_SPE implementations are reserved so writing to 945 * them does not change anything */ 946 if (val > PR_FP_EXC_PRECISE) 947 return -EINVAL; 948 tsk->thread.fpexc_mode = __pack_fe01(val); 949 if (regs != NULL && (regs->msr & MSR_FP) != 0) 950 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1)) 951 | tsk->thread.fpexc_mode; 952 return 0; 953 } 954 955 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr) 956 { 957 unsigned int val; 958 959 if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) 960 #ifdef CONFIG_SPE 961 if (cpu_has_feature(CPU_FTR_SPE)) 962 val = tsk->thread.fpexc_mode; 963 else 964 return -EINVAL; 965 #else 966 return -EINVAL; 967 #endif 968 else 969 val = __unpack_fe01(tsk->thread.fpexc_mode); 970 return put_user(val, (unsigned int __user *) adr); 971 } 972 973 int set_endian(struct task_struct *tsk, unsigned int val) 974 { 975 struct pt_regs *regs = tsk->thread.regs; 976 977 if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) || 978 (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE))) 979 return -EINVAL; 980 981 if (regs == NULL) 982 return -EINVAL; 983 984 if (val == PR_ENDIAN_BIG) 985 regs->msr &= ~MSR_LE; 986 else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE) 987 regs->msr |= MSR_LE; 988 else 989 return -EINVAL; 990 991 return 0; 992 } 993 994 int get_endian(struct task_struct *tsk, unsigned long adr) 995 { 996 struct pt_regs *regs = tsk->thread.regs; 997 unsigned int val; 998 999 if (!cpu_has_feature(CPU_FTR_PPC_LE) && 1000 !cpu_has_feature(CPU_FTR_REAL_LE)) 1001 return -EINVAL; 1002 1003 if (regs == NULL) 1004 return -EINVAL; 1005 1006 if (regs->msr & MSR_LE) { 1007 if (cpu_has_feature(CPU_FTR_REAL_LE)) 1008 val = PR_ENDIAN_LITTLE; 1009 else 1010 val = PR_ENDIAN_PPC_LITTLE; 1011 } else 1012 val = PR_ENDIAN_BIG; 1013 1014 return put_user(val, (unsigned int __user *)adr); 1015 } 1016 1017 int set_unalign_ctl(struct task_struct *tsk, unsigned int val) 1018 { 1019 tsk->thread.align_ctl = val; 1020 return 0; 1021 } 1022 1023 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) 1024 { 1025 return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr); 1026 } 1027 1028 #define TRUNC_PTR(x) ((typeof(x))(((unsigned long)(x)) & 0xffffffff)) 1029 1030 int sys_clone(unsigned long clone_flags, unsigned long usp, 1031 int __user *parent_tidp, void __user *child_threadptr, 1032 int __user *child_tidp, int p6, 1033 struct pt_regs *regs) 1034 { 1035 CHECK_FULL_REGS(regs); 1036 if (usp == 0) 1037 usp = regs->gpr[1]; /* stack pointer for child */ 1038 #ifdef CONFIG_PPC64 1039 if (is_32bit_task()) { 1040 parent_tidp = TRUNC_PTR(parent_tidp); 1041 child_tidp = TRUNC_PTR(child_tidp); 1042 } 1043 #endif 1044 return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp); 1045 } 1046 1047 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3, 1048 unsigned long p4, unsigned long p5, unsigned long p6, 1049 struct pt_regs *regs) 1050 { 1051 CHECK_FULL_REGS(regs); 1052 return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL); 1053 } 1054 1055 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3, 1056 unsigned long p4, unsigned long p5, unsigned long p6, 1057 struct pt_regs *regs) 1058 { 1059 CHECK_FULL_REGS(regs); 1060 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1], 1061 regs, 0, NULL, NULL); 1062 } 1063 1064 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2, 1065 unsigned long a3, unsigned long a4, unsigned long a5, 1066 struct pt_regs *regs) 1067 { 1068 int error; 1069 char *filename; 1070 1071 filename = getname((const char __user *) a0); 1072 error = PTR_ERR(filename); 1073 if (IS_ERR(filename)) 1074 goto out; 1075 flush_fp_to_thread(current); 1076 flush_altivec_to_thread(current); 1077 flush_spe_to_thread(current); 1078 error = do_execve(filename, 1079 (const char __user *const __user *) a1, 1080 (const char __user *const __user *) a2, regs); 1081 putname(filename); 1082 out: 1083 return error; 1084 } 1085 1086 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, 1087 unsigned long nbytes) 1088 { 1089 unsigned long stack_page; 1090 unsigned long cpu = task_cpu(p); 1091 1092 /* 1093 * Avoid crashing if the stack has overflowed and corrupted 1094 * task_cpu(p), which is in the thread_info struct. 1095 */ 1096 if (cpu < NR_CPUS && cpu_possible(cpu)) { 1097 stack_page = (unsigned long) hardirq_ctx[cpu]; 1098 if (sp >= stack_page + sizeof(struct thread_struct) 1099 && sp <= stack_page + THREAD_SIZE - nbytes) 1100 return 1; 1101 1102 stack_page = (unsigned long) softirq_ctx[cpu]; 1103 if (sp >= stack_page + sizeof(struct thread_struct) 1104 && sp <= stack_page + THREAD_SIZE - nbytes) 1105 return 1; 1106 } 1107 return 0; 1108 } 1109 1110 int validate_sp(unsigned long sp, struct task_struct *p, 1111 unsigned long nbytes) 1112 { 1113 unsigned long stack_page = (unsigned long)task_stack_page(p); 1114 1115 if (sp >= stack_page + sizeof(struct thread_struct) 1116 && sp <= stack_page + THREAD_SIZE - nbytes) 1117 return 1; 1118 1119 return valid_irq_stack(sp, p, nbytes); 1120 } 1121 1122 EXPORT_SYMBOL(validate_sp); 1123 1124 unsigned long get_wchan(struct task_struct *p) 1125 { 1126 unsigned long ip, sp; 1127 int count = 0; 1128 1129 if (!p || p == current || p->state == TASK_RUNNING) 1130 return 0; 1131 1132 sp = p->thread.ksp; 1133 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1134 return 0; 1135 1136 do { 1137 sp = *(unsigned long *)sp; 1138 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) 1139 return 0; 1140 if (count > 0) { 1141 ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE]; 1142 if (!in_sched_functions(ip)) 1143 return ip; 1144 } 1145 } while (count++ < 16); 1146 return 0; 1147 } 1148 1149 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; 1150 1151 void show_stack(struct task_struct *tsk, unsigned long *stack) 1152 { 1153 unsigned long sp, ip, lr, newsp; 1154 int count = 0; 1155 int firstframe = 1; 1156 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1157 int curr_frame = current->curr_ret_stack; 1158 extern void return_to_handler(void); 1159 unsigned long rth = (unsigned long)return_to_handler; 1160 unsigned long mrth = -1; 1161 #ifdef CONFIG_PPC64 1162 extern void mod_return_to_handler(void); 1163 rth = *(unsigned long *)rth; 1164 mrth = (unsigned long)mod_return_to_handler; 1165 mrth = *(unsigned long *)mrth; 1166 #endif 1167 #endif 1168 1169 sp = (unsigned long) stack; 1170 if (tsk == NULL) 1171 tsk = current; 1172 if (sp == 0) { 1173 if (tsk == current) 1174 asm("mr %0,1" : "=r" (sp)); 1175 else 1176 sp = tsk->thread.ksp; 1177 } 1178 1179 lr = 0; 1180 printk("Call Trace:\n"); 1181 do { 1182 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) 1183 return; 1184 1185 stack = (unsigned long *) sp; 1186 newsp = stack[0]; 1187 ip = stack[STACK_FRAME_LR_SAVE]; 1188 if (!firstframe || ip != lr) { 1189 printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); 1190 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1191 if ((ip == rth || ip == mrth) && curr_frame >= 0) { 1192 printk(" (%pS)", 1193 (void *)current->ret_stack[curr_frame].ret); 1194 curr_frame--; 1195 } 1196 #endif 1197 if (firstframe) 1198 printk(" (unreliable)"); 1199 printk("\n"); 1200 } 1201 firstframe = 0; 1202 1203 /* 1204 * See if this is an exception frame. 1205 * We look for the "regshere" marker in the current frame. 1206 */ 1207 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE) 1208 && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { 1209 struct pt_regs *regs = (struct pt_regs *) 1210 (sp + STACK_FRAME_OVERHEAD); 1211 lr = regs->link; 1212 printk("--- Exception: %lx at %pS\n LR = %pS\n", 1213 regs->trap, (void *)regs->nip, (void *)lr); 1214 firstframe = 1; 1215 } 1216 1217 sp = newsp; 1218 } while (count++ < kstack_depth_to_print); 1219 } 1220 1221 void dump_stack(void) 1222 { 1223 show_stack(current, NULL); 1224 } 1225 EXPORT_SYMBOL(dump_stack); 1226 1227 #ifdef CONFIG_PPC64 1228 /* Called with hard IRQs off */ 1229 void __ppc64_runlatch_on(void) 1230 { 1231 struct thread_info *ti = current_thread_info(); 1232 unsigned long ctrl; 1233 1234 ctrl = mfspr(SPRN_CTRLF); 1235 ctrl |= CTRL_RUNLATCH; 1236 mtspr(SPRN_CTRLT, ctrl); 1237 1238 ti->local_flags |= _TLF_RUNLATCH; 1239 } 1240 1241 /* Called with hard IRQs off */ 1242 void __ppc64_runlatch_off(void) 1243 { 1244 struct thread_info *ti = current_thread_info(); 1245 unsigned long ctrl; 1246 1247 ti->local_flags &= ~_TLF_RUNLATCH; 1248 1249 ctrl = mfspr(SPRN_CTRLF); 1250 ctrl &= ~CTRL_RUNLATCH; 1251 mtspr(SPRN_CTRLT, ctrl); 1252 } 1253 #endif /* CONFIG_PPC64 */ 1254 1255 #if THREAD_SHIFT < PAGE_SHIFT 1256 1257 static struct kmem_cache *thread_info_cache; 1258 1259 struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node) 1260 { 1261 struct thread_info *ti; 1262 1263 ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node); 1264 if (unlikely(ti == NULL)) 1265 return NULL; 1266 #ifdef CONFIG_DEBUG_STACK_USAGE 1267 memset(ti, 0, THREAD_SIZE); 1268 #endif 1269 return ti; 1270 } 1271 1272 void free_thread_info(struct thread_info *ti) 1273 { 1274 kmem_cache_free(thread_info_cache, ti); 1275 } 1276 1277 void thread_info_cache_init(void) 1278 { 1279 thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE, 1280 THREAD_SIZE, 0, NULL); 1281 BUG_ON(thread_info_cache == NULL); 1282 } 1283 1284 #endif /* THREAD_SHIFT < PAGE_SHIFT */ 1285 1286 unsigned long arch_align_stack(unsigned long sp) 1287 { 1288 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 1289 sp -= get_random_int() & ~PAGE_MASK; 1290 return sp & ~0xf; 1291 } 1292 1293 static inline unsigned long brk_rnd(void) 1294 { 1295 unsigned long rnd = 0; 1296 1297 /* 8MB for 32bit, 1GB for 64bit */ 1298 if (is_32bit_task()) 1299 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT))); 1300 else 1301 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT))); 1302 1303 return rnd << PAGE_SHIFT; 1304 } 1305 1306 unsigned long arch_randomize_brk(struct mm_struct *mm) 1307 { 1308 unsigned long base = mm->brk; 1309 unsigned long ret; 1310 1311 #ifdef CONFIG_PPC_STD_MMU_64 1312 /* 1313 * If we are using 1TB segments and we are allowed to randomise 1314 * the heap, we can put it above 1TB so it is backed by a 1TB 1315 * segment. Otherwise the heap will be in the bottom 1TB 1316 * which always uses 256MB segments and this may result in a 1317 * performance penalty. 1318 */ 1319 if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T)) 1320 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T); 1321 #endif 1322 1323 ret = PAGE_ALIGN(base + brk_rnd()); 1324 1325 if (ret < mm->brk) 1326 return mm->brk; 1327 1328 return ret; 1329 } 1330 1331 unsigned long randomize_et_dyn(unsigned long base) 1332 { 1333 unsigned long ret = PAGE_ALIGN(base + brk_rnd()); 1334 1335 if (ret < base) 1336 return base; 1337 1338 return ret; 1339 } 1340