1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  Derived from "arch/i386/kernel/process.c"
   4 *    Copyright (C) 1995  Linus Torvalds
   5 *
   6 *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   7 *  Paul Mackerras (paulus@cs.anu.edu.au)
   8 *
   9 *  PowerPC version
  10 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 
 
 
 
 
  11 */
  12
  13#include <linux/errno.h>
  14#include <linux/sched.h>
  15#include <linux/sched/debug.h>
  16#include <linux/sched/task.h>
  17#include <linux/sched/task_stack.h>
  18#include <linux/kernel.h>
  19#include <linux/mm.h>
  20#include <linux/smp.h>
  21#include <linux/stddef.h>
  22#include <linux/unistd.h>
  23#include <linux/ptrace.h>
  24#include <linux/slab.h>
  25#include <linux/user.h>
  26#include <linux/elf.h>
  27#include <linux/prctl.h>
  28#include <linux/init_task.h>
  29#include <linux/export.h>
  30#include <linux/kallsyms.h>
  31#include <linux/mqueue.h>
  32#include <linux/hardirq.h>
  33#include <linux/utsname.h>
  34#include <linux/ftrace.h>
  35#include <linux/kernel_stat.h>
  36#include <linux/personality.h>
 
  37#include <linux/hw_breakpoint.h>
  38#include <linux/uaccess.h>
  39#include <linux/pkeys.h>
  40#include <linux/seq_buf.h>
  41
  42#include <asm/interrupt.h>
  43#include <asm/io.h>
  44#include <asm/processor.h>
  45#include <asm/mmu.h>
 
  46#include <asm/machdep.h>
  47#include <asm/time.h>
  48#include <asm/runlatch.h>
  49#include <asm/syscalls.h>
  50#include <asm/switch_to.h>
  51#include <asm/tm.h>
  52#include <asm/debug.h>
  53#ifdef CONFIG_PPC64
  54#include <asm/firmware.h>
  55#include <asm/hw_irq.h>
  56#endif
  57#include <asm/code-patching.h>
  58#include <asm/exec.h>
  59#include <asm/livepatch.h>
  60#include <asm/cpu_has_feature.h>
  61#include <asm/asm-prototypes.h>
  62#include <asm/stacktrace.h>
  63#include <asm/hw_breakpoint.h>
  64
  65#include <linux/kprobes.h>
  66#include <linux/kdebug.h>
  67
  68/* Transactional Memory debug */
  69#ifdef TM_DEBUG_SW
  70#define TM_DEBUG(x...) printk(KERN_INFO x)
  71#else
  72#define TM_DEBUG(x...) do { } while(0)
  73#endif
  74
  75extern unsigned long _get_SP(void);
  76
  77#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  78/*
  79 * Are we running in "Suspend disabled" mode? If so we have to block any
  80 * sigreturn that would get us into suspended state, and we also warn in some
  81 * other paths that we should never reach with suspend disabled.
  82 */
  83bool tm_suspend_disabled __ro_after_init = false;
  84
  85static void check_if_tm_restore_required(struct task_struct *tsk)
  86{
  87	/*
  88	 * If we are saving the current thread's registers, and the
  89	 * thread is in a transactional state, set the TIF_RESTORE_TM
  90	 * bit so that we know to restore the registers before
  91	 * returning to userspace.
  92	 */
  93	if (tsk == current && tsk->thread.regs &&
  94	    MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
  95	    !test_thread_flag(TIF_RESTORE_TM)) {
  96		regs_set_return_msr(&tsk->thread.ckpt_regs,
  97						tsk->thread.regs->msr);
  98		set_thread_flag(TIF_RESTORE_TM);
  99	}
 100}
 101
 102#else
 103static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
 104#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 105
 106bool strict_msr_control;
 107EXPORT_SYMBOL(strict_msr_control);
 108
 109static int __init enable_strict_msr_control(char *str)
 110{
 111	strict_msr_control = true;
 112	pr_info("Enabling strict facility control\n");
 113
 114	return 0;
 115}
 116early_param("ppc_strict_facility_enable", enable_strict_msr_control);
 117
 118/* notrace because it's called by restore_math */
 119unsigned long notrace msr_check_and_set(unsigned long bits)
 120{
 121	unsigned long oldmsr = mfmsr();
 122	unsigned long newmsr;
 123
 124	newmsr = oldmsr | bits;
 125
 
 126	if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
 127		newmsr |= MSR_VSX;
 
 128
 129	if (oldmsr != newmsr)
 130		newmsr = mtmsr_isync_irqsafe(newmsr);
 131
 132	return newmsr;
 133}
 134EXPORT_SYMBOL_GPL(msr_check_and_set);
 135
 136/* notrace because it's called by restore_math */
 137void notrace __msr_check_and_clear(unsigned long bits)
 138{
 139	unsigned long oldmsr = mfmsr();
 140	unsigned long newmsr;
 141
 142	newmsr = oldmsr & ~bits;
 143
 
 144	if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
 145		newmsr &= ~MSR_VSX;
 
 146
 147	if (oldmsr != newmsr)
 148		mtmsr_isync_irqsafe(newmsr);
 149}
 150EXPORT_SYMBOL(__msr_check_and_clear);
 151
 152#ifdef CONFIG_PPC_FPU
 153static void __giveup_fpu(struct task_struct *tsk)
 154{
 155	unsigned long msr;
 156
 157	save_fpu(tsk);
 158	msr = tsk->thread.regs->msr;
 159	msr &= ~(MSR_FP|MSR_FE0|MSR_FE1);
 160	if (cpu_has_feature(CPU_FTR_VSX))
 161		msr &= ~MSR_VSX;
 162	regs_set_return_msr(tsk->thread.regs, msr);
 163}
 164
 165void giveup_fpu(struct task_struct *tsk)
 166{
 167	check_if_tm_restore_required(tsk);
 168
 169	msr_check_and_set(MSR_FP);
 170	__giveup_fpu(tsk);
 171	msr_check_and_clear(MSR_FP);
 172}
 173EXPORT_SYMBOL(giveup_fpu);
 174
 175/*
 176 * Make sure the floating-point register state in the
 177 * the thread_struct is up to date for task tsk.
 178 */
 179void flush_fp_to_thread(struct task_struct *tsk)
 180{
 181	if (tsk->thread.regs) {
 182		/*
 183		 * We need to disable preemption here because if we didn't,
 184		 * another process could get scheduled after the regs->msr
 185		 * test but before we have finished saving the FP registers
 186		 * to the thread_struct.  That process could take over the
 187		 * FPU, and then when we get scheduled again we would store
 188		 * bogus values for the remaining FP registers.
 189		 */
 190		preempt_disable();
 191		if (tsk->thread.regs->msr & MSR_FP) {
 192			/*
 193			 * This should only ever be called for current or
 194			 * for a stopped child process.  Since we save away
 195			 * the FP register state on context switch,
 196			 * there is something wrong if a stopped child appears
 197			 * to still have its FP state in the CPU registers.
 198			 */
 199			BUG_ON(tsk != current);
 200			giveup_fpu(tsk);
 201		}
 202		preempt_enable();
 203	}
 204}
 205EXPORT_SYMBOL_GPL(flush_fp_to_thread);
 206
 207void enable_kernel_fp(void)
 208{
 209	unsigned long cpumsr;
 210
 211	WARN_ON(preemptible());
 212
 213	cpumsr = msr_check_and_set(MSR_FP);
 214
 215	if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
 216		check_if_tm_restore_required(current);
 217		/*
 218		 * If a thread has already been reclaimed then the
 219		 * checkpointed registers are on the CPU but have definitely
 220		 * been saved by the reclaim code. Don't need to and *cannot*
 221		 * giveup as this would save  to the 'live' structure not the
 222		 * checkpointed structure.
 223		 */
 224		if (!MSR_TM_ACTIVE(cpumsr) &&
 225		     MSR_TM_ACTIVE(current->thread.regs->msr))
 226			return;
 227		__giveup_fpu(current);
 228	}
 229}
 230EXPORT_SYMBOL(enable_kernel_fp);
 
 
 
 
 
 
 
 
 
 231#else
 232static inline void __giveup_fpu(struct task_struct *tsk) { }
 233#endif /* CONFIG_PPC_FPU */
 234
 235#ifdef CONFIG_ALTIVEC
 
 
 236static void __giveup_altivec(struct task_struct *tsk)
 237{
 238	unsigned long msr;
 239
 240	save_altivec(tsk);
 241	msr = tsk->thread.regs->msr;
 242	msr &= ~MSR_VEC;
 243	if (cpu_has_feature(CPU_FTR_VSX))
 244		msr &= ~MSR_VSX;
 245	regs_set_return_msr(tsk->thread.regs, msr);
 246}
 247
 248void giveup_altivec(struct task_struct *tsk)
 249{
 250	check_if_tm_restore_required(tsk);
 251
 252	msr_check_and_set(MSR_VEC);
 253	__giveup_altivec(tsk);
 254	msr_check_and_clear(MSR_VEC);
 255}
 256EXPORT_SYMBOL(giveup_altivec);
 257
 258void enable_kernel_altivec(void)
 259{
 260	unsigned long cpumsr;
 261
 262	WARN_ON(preemptible());
 263
 264	cpumsr = msr_check_and_set(MSR_VEC);
 265
 266	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) {
 267		check_if_tm_restore_required(current);
 268		/*
 269		 * If a thread has already been reclaimed then the
 270		 * checkpointed registers are on the CPU but have definitely
 271		 * been saved by the reclaim code. Don't need to and *cannot*
 272		 * giveup as this would save  to the 'live' structure not the
 273		 * checkpointed structure.
 274		 */
 275		if (!MSR_TM_ACTIVE(cpumsr) &&
 276		     MSR_TM_ACTIVE(current->thread.regs->msr))
 277			return;
 278		__giveup_altivec(current);
 279	}
 280}
 281EXPORT_SYMBOL(enable_kernel_altivec);
 282
 283/*
 284 * Make sure the VMX/Altivec register state in the
 285 * the thread_struct is up to date for task tsk.
 286 */
 287void flush_altivec_to_thread(struct task_struct *tsk)
 288{
 289	if (tsk->thread.regs) {
 290		preempt_disable();
 291		if (tsk->thread.regs->msr & MSR_VEC) {
 292			BUG_ON(tsk != current);
 293			giveup_altivec(tsk);
 294		}
 295		preempt_enable();
 296	}
 297}
 298EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 299#endif /* CONFIG_ALTIVEC */
 300
 301#ifdef CONFIG_VSX
 302static void __giveup_vsx(struct task_struct *tsk)
 303{
 304	unsigned long msr = tsk->thread.regs->msr;
 305
 306	/*
 307	 * We should never be setting MSR_VSX without also setting
 308	 * MSR_FP and MSR_VEC
 309	 */
 310	WARN_ON((msr & MSR_VSX) && !((msr & MSR_FP) && (msr & MSR_VEC)));
 311
 312	/* __giveup_fpu will clear MSR_VSX */
 313	if (msr & MSR_FP)
 314		__giveup_fpu(tsk);
 315	if (msr & MSR_VEC)
 316		__giveup_altivec(tsk);
 
 317}
 318
 319static void giveup_vsx(struct task_struct *tsk)
 320{
 321	check_if_tm_restore_required(tsk);
 322
 323	msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
 324	__giveup_vsx(tsk);
 325	msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);
 326}
 327
 328void enable_kernel_vsx(void)
 329{
 330	unsigned long cpumsr;
 
 
 
 
 331
 
 
 332	WARN_ON(preemptible());
 333
 334	cpumsr = msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
 335
 336	if (current->thread.regs &&
 337	    (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) {
 338		check_if_tm_restore_required(current);
 339		/*
 340		 * If a thread has already been reclaimed then the
 341		 * checkpointed registers are on the CPU but have definitely
 342		 * been saved by the reclaim code. Don't need to and *cannot*
 343		 * giveup as this would save  to the 'live' structure not the
 344		 * checkpointed structure.
 345		 */
 346		if (!MSR_TM_ACTIVE(cpumsr) &&
 347		     MSR_TM_ACTIVE(current->thread.regs->msr))
 348			return;
 349		__giveup_vsx(current);
 350	}
 351}
 352EXPORT_SYMBOL(enable_kernel_vsx);
 353
 354void flush_vsx_to_thread(struct task_struct *tsk)
 355{
 356	if (tsk->thread.regs) {
 357		preempt_disable();
 358		if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) {
 359			BUG_ON(tsk != current);
 360			giveup_vsx(tsk);
 361		}
 362		preempt_enable();
 363	}
 364}
 365EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
 
 
 
 
 
 
 
 
 
 
 
 
 
 366#endif /* CONFIG_VSX */
 367
 368#ifdef CONFIG_SPE
 369void giveup_spe(struct task_struct *tsk)
 370{
 371	check_if_tm_restore_required(tsk);
 372
 373	msr_check_and_set(MSR_SPE);
 374	__giveup_spe(tsk);
 375	msr_check_and_clear(MSR_SPE);
 376}
 377EXPORT_SYMBOL(giveup_spe);
 378
 379void enable_kernel_spe(void)
 380{
 381	WARN_ON(preemptible());
 382
 383	msr_check_and_set(MSR_SPE);
 384
 385	if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) {
 386		check_if_tm_restore_required(current);
 387		__giveup_spe(current);
 388	}
 389}
 390EXPORT_SYMBOL(enable_kernel_spe);
 391
 392void flush_spe_to_thread(struct task_struct *tsk)
 393{
 394	if (tsk->thread.regs) {
 395		preempt_disable();
 396		if (tsk->thread.regs->msr & MSR_SPE) {
 397			BUG_ON(tsk != current);
 398			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 399			giveup_spe(tsk);
 400		}
 401		preempt_enable();
 402	}
 403}
 404#endif /* CONFIG_SPE */
 405
 406static unsigned long msr_all_available;
 407
 408static int __init init_msr_all_available(void)
 409{
 410	if (IS_ENABLED(CONFIG_PPC_FPU))
 411		msr_all_available |= MSR_FP;
 
 
 412	if (cpu_has_feature(CPU_FTR_ALTIVEC))
 413		msr_all_available |= MSR_VEC;
 
 
 414	if (cpu_has_feature(CPU_FTR_VSX))
 415		msr_all_available |= MSR_VSX;
 
 
 416	if (cpu_has_feature(CPU_FTR_SPE))
 417		msr_all_available |= MSR_SPE;
 
 418
 419	return 0;
 420}
 421early_initcall(init_msr_all_available);
 422
 423void giveup_all(struct task_struct *tsk)
 424{
 425	unsigned long usermsr;
 426
 427	if (!tsk->thread.regs)
 428		return;
 429
 430	check_if_tm_restore_required(tsk);
 431
 432	usermsr = tsk->thread.regs->msr;
 433
 434	if ((usermsr & msr_all_available) == 0)
 435		return;
 436
 437	msr_check_and_set(msr_all_available);
 438
 439	WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC)));
 440
 441	if (usermsr & MSR_FP)
 442		__giveup_fpu(tsk);
 
 
 443	if (usermsr & MSR_VEC)
 444		__giveup_altivec(tsk);
 
 
 
 
 
 
 445	if (usermsr & MSR_SPE)
 446		__giveup_spe(tsk);
 
 447
 448	msr_check_and_clear(msr_all_available);
 449}
 450EXPORT_SYMBOL(giveup_all);
 451
 452#ifdef CONFIG_PPC_BOOK3S_64
 453#ifdef CONFIG_PPC_FPU
 454static bool should_restore_fp(void)
 455{
 456	if (current->thread.load_fp) {
 457		current->thread.load_fp++;
 458		return true;
 459	}
 460	return false;
 461}
 462
 463static void do_restore_fp(void)
 464{
 465	load_fp_state(&current->thread.fp_state);
 466}
 467#else
 468static bool should_restore_fp(void) { return false; }
 469static void do_restore_fp(void) { }
 470#endif /* CONFIG_PPC_FPU */
 471
 472#ifdef CONFIG_ALTIVEC
 473static bool should_restore_altivec(void)
 474{
 475	if (cpu_has_feature(CPU_FTR_ALTIVEC) && (current->thread.load_vec)) {
 476		current->thread.load_vec++;
 477		return true;
 478	}
 479	return false;
 480}
 481
 482static void do_restore_altivec(void)
 483{
 484	load_vr_state(&current->thread.vr_state);
 485	current->thread.used_vr = 1;
 486}
 487#else
 488static bool should_restore_altivec(void) { return false; }
 489static void do_restore_altivec(void) { }
 490#endif /* CONFIG_ALTIVEC */
 491
 492static bool should_restore_vsx(void)
 493{
 494	if (cpu_has_feature(CPU_FTR_VSX))
 495		return true;
 496	return false;
 497}
 498#ifdef CONFIG_VSX
 499static void do_restore_vsx(void)
 500{
 501	current->thread.used_vsr = 1;
 502}
 503#else
 504static void do_restore_vsx(void) { }
 505#endif /* CONFIG_VSX */
 506
 507/*
 508 * The exception exit path calls restore_math() with interrupts hard disabled
 509 * but the soft irq state not "reconciled". ftrace code that calls
 510 * local_irq_save/restore causes warnings.
 511 *
 512 * Rather than complicate the exit path, just don't trace restore_math. This
 513 * could be done by having ftrace entry code check for this un-reconciled
 514 * condition where MSR[EE]=0 and PACA_IRQ_HARD_DIS is not set, and
 515 * temporarily fix it up for the duration of the ftrace call.
 516 */
 517void notrace restore_math(struct pt_regs *regs)
 518{
 519	unsigned long msr;
 520	unsigned long new_msr = 0;
 
 
 521
 522	msr = regs->msr;
 
 523
 524	/*
 525	 * new_msr tracks the facilities that are to be restored. Only reload
 526	 * if the bit is not set in the user MSR (if it is set, the registers
 527	 * are live for the user thread).
 528	 */
 529	if ((!(msr & MSR_FP)) && should_restore_fp())
 530		new_msr |= MSR_FP;
 531
 532	if ((!(msr & MSR_VEC)) && should_restore_altivec())
 533		new_msr |= MSR_VEC;
 534
 535	if ((!(msr & MSR_VSX)) && should_restore_vsx()) {
 536		if (((msr | new_msr) & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC))
 537			new_msr |= MSR_VSX;
 538	}
 539
 540	if (new_msr) {
 541		unsigned long fpexc_mode = 0;
 542
 543		msr_check_and_set(new_msr);
 544
 545		if (new_msr & MSR_FP) {
 546			do_restore_fp();
 547
 548			// This also covers VSX, because VSX implies FP
 549			fpexc_mode = current->thread.fpexc_mode;
 550		}
 551
 552		if (new_msr & MSR_VEC)
 553			do_restore_altivec();
 554
 555		if (new_msr & MSR_VSX)
 556			do_restore_vsx();
 557
 558		msr_check_and_clear(new_msr);
 559
 560		regs_set_return_msr(regs, regs->msr | new_msr | fpexc_mode);
 561	}
 562}
 563#endif /* CONFIG_PPC_BOOK3S_64 */
 564
 565static void save_all(struct task_struct *tsk)
 566{
 567	unsigned long usermsr;
 568
 569	if (!tsk->thread.regs)
 570		return;
 571
 572	usermsr = tsk->thread.regs->msr;
 573
 574	if ((usermsr & msr_all_available) == 0)
 575		return;
 576
 577	msr_check_and_set(msr_all_available);
 578
 579	WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC)));
 580
 581	if (usermsr & MSR_FP)
 582		save_fpu(tsk);
 
 
 
 
 
 583
 584	if (usermsr & MSR_VEC)
 585		save_altivec(tsk);
 
 586
 587	if (usermsr & MSR_SPE)
 588		__giveup_spe(tsk);
 589
 590	msr_check_and_clear(msr_all_available);
 591}
 592
 593void flush_all_to_thread(struct task_struct *tsk)
 594{
 595	if (tsk->thread.regs) {
 596		preempt_disable();
 597		BUG_ON(tsk != current);
 
 
 598#ifdef CONFIG_SPE
 599		if (tsk->thread.regs->msr & MSR_SPE)
 600			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 601#endif
 602		save_all(tsk);
 603
 604		preempt_enable();
 605	}
 606}
 607EXPORT_SYMBOL(flush_all_to_thread);
 608
 609#ifdef CONFIG_PPC_ADV_DEBUG_REGS
 610void do_send_trap(struct pt_regs *regs, unsigned long address,
 611		  unsigned long error_code, int breakpt)
 612{
 613	current->thread.trap_nr = TRAP_HWBKPT;
 
 
 614	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 615			11, SIGSEGV) == NOTIFY_STOP)
 616		return;
 617
 618	/* Deliver the signal to userspace */
 619	force_sig_ptrace_errno_trap(breakpt, /* breakpoint or watchpoint id */
 620				    (void __user *)address);
 
 
 
 621}
 622#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
 623
 624static void do_break_handler(struct pt_regs *regs)
 625{
 626	struct arch_hw_breakpoint null_brk = {0};
 627	struct arch_hw_breakpoint *info;
 628	ppc_inst_t instr = ppc_inst(0);
 629	int type = 0;
 630	int size = 0;
 631	unsigned long ea;
 632	int i;
 633
 634	/*
 635	 * If underneath hw supports only one watchpoint, we know it
 636	 * caused exception. 8xx also falls into this category.
 637	 */
 638	if (nr_wp_slots() == 1) {
 639		__set_breakpoint(0, &null_brk);
 640		current->thread.hw_brk[0] = null_brk;
 641		current->thread.hw_brk[0].flags |= HW_BRK_FLAG_DISABLED;
 642		return;
 643	}
 644
 645	/* Otherwise find out which DAWR caused exception and disable it. */
 646	wp_get_instr_detail(regs, &instr, &type, &size, &ea);
 647
 648	for (i = 0; i < nr_wp_slots(); i++) {
 649		info = &current->thread.hw_brk[i];
 650		if (!info->address)
 651			continue;
 652
 653		if (wp_check_constraints(regs, instr, ea, type, size, info)) {
 654			__set_breakpoint(i, &null_brk);
 655			current->thread.hw_brk[i] = null_brk;
 656			current->thread.hw_brk[i].flags |= HW_BRK_FLAG_DISABLED;
 657		}
 658	}
 659}
 660
 661DEFINE_INTERRUPT_HANDLER(do_break)
 662{
 663	current->thread.trap_nr = TRAP_HWBKPT;
 664	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, regs->dsisr,
 665			11, SIGSEGV) == NOTIFY_STOP)
 666		return;
 667
 668	if (debugger_break_match(regs))
 669		return;
 670
 671	/*
 672	 * We reach here only when watchpoint exception is generated by ptrace
 673	 * event (or hw is buggy!). Now if CONFIG_HAVE_HW_BREAKPOINT is set,
 674	 * watchpoint is already handled by hw_breakpoint_handler() so we don't
 675	 * have to do anything. But when CONFIG_HAVE_HW_BREAKPOINT is not set,
 676	 * we need to manually handle the watchpoint here.
 677	 */
 678	if (!IS_ENABLED(CONFIG_HAVE_HW_BREAKPOINT))
 679		do_break_handler(regs);
 680
 681	/* Deliver the signal to userspace */
 682	force_sig_fault(SIGTRAP, TRAP_HWBKPT, (void __user *)regs->dar);
 
 
 
 
 683}
 684#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
 685
 686static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk[HBP_NUM_MAX]);
 687
 688#ifdef CONFIG_PPC_ADV_DEBUG_REGS
 689/*
 690 * Set the debug registers back to their default "safe" values.
 691 */
 692static void set_debug_reg_defaults(struct thread_struct *thread)
 693{
 694	thread->debug.iac1 = thread->debug.iac2 = 0;
 695#if CONFIG_PPC_ADV_DEBUG_IACS > 2
 696	thread->debug.iac3 = thread->debug.iac4 = 0;
 697#endif
 698	thread->debug.dac1 = thread->debug.dac2 = 0;
 699#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 700	thread->debug.dvc1 = thread->debug.dvc2 = 0;
 701#endif
 702	thread->debug.dbcr0 = 0;
 703#ifdef CONFIG_BOOKE
 704	/*
 705	 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 706	 */
 707	thread->debug.dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
 708			DBCR1_IAC3US | DBCR1_IAC4US;
 709	/*
 710	 * Force Data Address Compare User/Supervisor bits to be User-only
 711	 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 712	 */
 713	thread->debug.dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 714#else
 715	thread->debug.dbcr1 = 0;
 716#endif
 717}
 718
 719static void prime_debug_regs(struct debug_reg *debug)
 720{
 721	/*
 722	 * We could have inherited MSR_DE from userspace, since
 723	 * it doesn't get cleared on exception entry.  Make sure
 724	 * MSR_DE is clear before we enable any debug events.
 725	 */
 726	mtmsr(mfmsr() & ~MSR_DE);
 727
 728	mtspr(SPRN_IAC1, debug->iac1);
 729	mtspr(SPRN_IAC2, debug->iac2);
 730#if CONFIG_PPC_ADV_DEBUG_IACS > 2
 731	mtspr(SPRN_IAC3, debug->iac3);
 732	mtspr(SPRN_IAC4, debug->iac4);
 733#endif
 734	mtspr(SPRN_DAC1, debug->dac1);
 735	mtspr(SPRN_DAC2, debug->dac2);
 736#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 737	mtspr(SPRN_DVC1, debug->dvc1);
 738	mtspr(SPRN_DVC2, debug->dvc2);
 739#endif
 740	mtspr(SPRN_DBCR0, debug->dbcr0);
 741	mtspr(SPRN_DBCR1, debug->dbcr1);
 742#ifdef CONFIG_BOOKE
 743	mtspr(SPRN_DBCR2, debug->dbcr2);
 744#endif
 745}
 746/*
 747 * Unless neither the old or new thread are making use of the
 748 * debug registers, set the debug registers from the values
 749 * stored in the new thread.
 750 */
 751void switch_booke_debug_regs(struct debug_reg *new_debug)
 752{
 753	if ((current->thread.debug.dbcr0 & DBCR0_IDM)
 754		|| (new_debug->dbcr0 & DBCR0_IDM))
 755			prime_debug_regs(new_debug);
 756}
 757EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
 758#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
 759#ifndef CONFIG_HAVE_HW_BREAKPOINT
 760static void set_breakpoint(int i, struct arch_hw_breakpoint *brk)
 761{
 762	preempt_disable();
 763	__set_breakpoint(i, brk);
 764	preempt_enable();
 765}
 
 
 766
 767static void set_debug_reg_defaults(struct thread_struct *thread)
 
 768{
 769	int i;
 770	struct arch_hw_breakpoint null_brk = {0};
 771
 772	for (i = 0; i < nr_wp_slots(); i++) {
 773		thread->hw_brk[i] = null_brk;
 774		if (ppc_breakpoint_available())
 775			set_breakpoint(i, &thread->hw_brk[i]);
 776	}
 777}
 778
 779static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
 780				struct arch_hw_breakpoint *b)
 781{
 782	if (a->address != b->address)
 783		return false;
 784	if (a->type != b->type)
 785		return false;
 786	if (a->len != b->len)
 787		return false;
 788	/* no need to check hw_len. it's calculated from address and len */
 789	return true;
 790}
 791
 792static void switch_hw_breakpoint(struct task_struct *new)
 793{
 794	int i;
 795
 796	for (i = 0; i < nr_wp_slots(); i++) {
 797		if (likely(hw_brk_match(this_cpu_ptr(&current_brk[i]),
 798					&new->thread.hw_brk[i])))
 799			continue;
 800
 801		__set_breakpoint(i, &new->thread.hw_brk[i]);
 802	}
 803}
 804#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 805#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
 806
 807static inline int set_dabr(struct arch_hw_breakpoint *brk)
 808{
 809	unsigned long dabr, dabrx;
 810
 811	dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR);
 812	dabrx = ((brk->type >> 3) & 0x7);
 813
 814	if (ppc_md.set_dabr)
 815		return ppc_md.set_dabr(dabr, dabrx);
 816
 817	if (IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {
 818		mtspr(SPRN_DAC1, dabr);
 819		if (IS_ENABLED(CONFIG_PPC_47x))
 820			isync();
 821		return 0;
 822	} else if (IS_ENABLED(CONFIG_PPC_BOOK3S)) {
 823		mtspr(SPRN_DABR, dabr);
 824		if (cpu_has_feature(CPU_FTR_DABRX))
 825			mtspr(SPRN_DABRX, dabrx);
 826		return 0;
 827	} else {
 828		return -EINVAL;
 829	}
 830}
 831
 832static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
 833{
 834	unsigned long lctrl1 = LCTRL1_CTE_GT | LCTRL1_CTF_LT | LCTRL1_CRWE_RW |
 835			       LCTRL1_CRWF_RW;
 836	unsigned long lctrl2 = LCTRL2_LW0EN | LCTRL2_LW0LADC | LCTRL2_SLW0EN;
 837	unsigned long start_addr = ALIGN_DOWN(brk->address, HW_BREAKPOINT_SIZE);
 838	unsigned long end_addr = ALIGN(brk->address + brk->len, HW_BREAKPOINT_SIZE);
 839
 840	if (start_addr == 0)
 841		lctrl2 |= LCTRL2_LW0LA_F;
 842	else if (end_addr == 0)
 843		lctrl2 |= LCTRL2_LW0LA_E;
 844	else
 845		lctrl2 |= LCTRL2_LW0LA_EandF;
 846
 847	mtspr(SPRN_LCTRL2, 0);
 848
 849	if ((brk->type & HW_BRK_TYPE_RDWR) == 0)
 850		return 0;
 851
 852	if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_READ)
 853		lctrl1 |= LCTRL1_CRWE_RO | LCTRL1_CRWF_RO;
 854	if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_WRITE)
 855		lctrl1 |= LCTRL1_CRWE_WO | LCTRL1_CRWF_WO;
 856
 857	mtspr(SPRN_CMPE, start_addr - 1);
 858	mtspr(SPRN_CMPF, end_addr);
 859	mtspr(SPRN_LCTRL1, lctrl1);
 860	mtspr(SPRN_LCTRL2, lctrl2);
 861
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 862	return 0;
 863}
 864
 865static void set_hw_breakpoint(int nr, struct arch_hw_breakpoint *brk)
 866{
 867	if (dawr_enabled())
 868		// Power8 or later
 869		set_dawr(nr, brk);
 870	else if (IS_ENABLED(CONFIG_PPC_8xx))
 871		set_breakpoint_8xx(brk);
 872	else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
 873		// Power7 or earlier
 874		set_dabr(brk);
 875	else
 876		// Shouldn't happen due to higher level checks
 877		WARN_ON_ONCE(1);
 878}
 879
 880void __set_breakpoint(int nr, struct arch_hw_breakpoint *brk)
 881{
 882	memcpy(this_cpu_ptr(&current_brk[nr]), brk, sizeof(*brk));
 883	set_hw_breakpoint(nr, brk);
 884}
 885
 886/* Check if we have DAWR or DABR hardware */
 887bool ppc_breakpoint_available(void)
 888{
 889	if (dawr_enabled())
 890		return true; /* POWER8 DAWR or POWER9 forced DAWR */
 891	if (cpu_has_feature(CPU_FTR_ARCH_207S))
 892		return false; /* POWER9 with DAWR disabled */
 893	/* DABR: Everything but POWER8 and POWER9 */
 894	return true;
 895}
 896EXPORT_SYMBOL_GPL(ppc_breakpoint_available);
 897
 898/* Disable the breakpoint in hardware without touching current_brk[] */
 899void suspend_breakpoints(void)
 900{
 901	struct arch_hw_breakpoint brk = {0};
 902	int i;
 903
 904	if (!ppc_breakpoint_available())
 905		return;
 906
 907	for (i = 0; i < nr_wp_slots(); i++)
 908		set_hw_breakpoint(i, &brk);
 909}
 910
 911/*
 912 * Re-enable breakpoints suspended by suspend_breakpoints() in hardware
 913 * from current_brk[]
 914 */
 915void restore_breakpoints(void)
 916{
 917	int i;
 918
 919	if (!ppc_breakpoint_available())
 920		return;
 921
 922	for (i = 0; i < nr_wp_slots(); i++)
 923		set_hw_breakpoint(i, this_cpu_ptr(&current_brk[i]));
 924}
 925
 926#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 927
 928static inline bool tm_enabled(struct task_struct *tsk)
 929{
 930	return tsk && tsk->thread.regs && (tsk->thread.regs->msr & MSR_TM);
 931}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 932
 933static void tm_reclaim_thread(struct thread_struct *thr, uint8_t cause)
 934{
 935	/*
 936	 * Use the current MSR TM suspended bit to track if we have
 937	 * checkpointed state outstanding.
 938	 * On signal delivery, we'd normally reclaim the checkpointed
 939	 * state to obtain stack pointer (see:get_tm_stackpointer()).
 940	 * This will then directly return to userspace without going
 941	 * through __switch_to(). However, if the stack frame is bad,
 942	 * we need to exit this thread which calls __switch_to() which
 943	 * will again attempt to reclaim the already saved tm state.
 944	 * Hence we need to check that we've not already reclaimed
 945	 * this state.
 946	 * We do this using the current MSR, rather tracking it in
 947	 * some specific thread_struct bit, as it has the additional
 948	 * benefit of checking for a potential TM bad thing exception.
 949	 */
 950	if (!MSR_TM_SUSPENDED(mfmsr()))
 951		return;
 952
 953	giveup_all(container_of(thr, struct task_struct, thread));
 954
 955	tm_reclaim(thr, cause);
 956
 957	/*
 958	 * If we are in a transaction and FP is off then we can't have
 959	 * used FP inside that transaction. Hence the checkpointed
 960	 * state is the same as the live state. We need to copy the
 961	 * live state to the checkpointed state so that when the
 962	 * transaction is restored, the checkpointed state is correct
 963	 * and the aborted transaction sees the correct state. We use
 964	 * ckpt_regs.msr here as that's what tm_reclaim will use to
 965	 * determine if it's going to write the checkpointed state or
 966	 * not. So either this will write the checkpointed registers,
 967	 * or reclaim will. Similarly for VMX.
 968	 */
 969	if ((thr->ckpt_regs.msr & MSR_FP) == 0)
 970		memcpy(&thr->ckfp_state, &thr->fp_state,
 971		       sizeof(struct thread_fp_state));
 972	if ((thr->ckpt_regs.msr & MSR_VEC) == 0)
 973		memcpy(&thr->ckvr_state, &thr->vr_state,
 974		       sizeof(struct thread_vr_state));
 975}
 976
 977void tm_reclaim_current(uint8_t cause)
 978{
 979	tm_enable();
 980	tm_reclaim_thread(&current->thread, cause);
 981}
 982
 983static inline void tm_reclaim_task(struct task_struct *tsk)
 984{
 985	/* We have to work out if we're switching from/to a task that's in the
 986	 * middle of a transaction.
 987	 *
 988	 * In switching we need to maintain a 2nd register state as
 989	 * oldtask->thread.ckpt_regs.  We tm_reclaim(oldproc); this saves the
 990	 * checkpointed (tbegin) state in ckpt_regs, ckfp_state and
 991	 * ckvr_state
 992	 *
 993	 * We also context switch (save) TFHAR/TEXASR/TFIAR in here.
 994	 */
 995	struct thread_struct *thr = &tsk->thread;
 996
 997	if (!thr->regs)
 998		return;
 999
1000	if (!MSR_TM_ACTIVE(thr->regs->msr))
1001		goto out_and_saveregs;
1002
1003	WARN_ON(tm_suspend_disabled);
 
 
 
 
 
 
1004
1005	TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
1006		 "ccr=%lx, msr=%lx, trap=%lx)\n",
1007		 tsk->pid, thr->regs->nip,
1008		 thr->regs->ccr, thr->regs->msr,
1009		 thr->regs->trap);
1010
1011	tm_reclaim_thread(thr, TM_CAUSE_RESCHED);
1012
1013	TM_DEBUG("--- tm_reclaim on pid %d complete\n",
1014		 tsk->pid);
1015
1016out_and_saveregs:
1017	/* Always save the regs here, even if a transaction's not active.
1018	 * This context-switches a thread's TM info SPRs.  We do it here to
1019	 * be consistent with the restore path (in recheckpoint) which
1020	 * cannot happen later in _switch().
1021	 */
1022	tm_save_sprs(thr);
1023}
1024
1025extern void __tm_recheckpoint(struct thread_struct *thread);
 
1026
1027void tm_recheckpoint(struct thread_struct *thread)
 
1028{
1029	unsigned long flags;
1030
1031	if (!(thread->regs->msr & MSR_TM))
1032		return;
1033
1034	/* We really can't be interrupted here as the TEXASR registers can't
1035	 * change and later in the trecheckpoint code, we have a userspace R1.
1036	 * So let's hard disable over this region.
1037	 */
1038	local_irq_save(flags);
1039	hard_irq_disable();
1040
1041	/* The TM SPRs are restored here, so that TEXASR.FS can be set
1042	 * before the trecheckpoint and no explosion occurs.
1043	 */
1044	tm_restore_sprs(thread);
1045
1046	__tm_recheckpoint(thread);
1047
1048	local_irq_restore(flags);
1049}
1050
1051static inline void tm_recheckpoint_new_task(struct task_struct *new)
1052{
 
 
1053	if (!cpu_has_feature(CPU_FTR_TM))
1054		return;
1055
1056	/* Recheckpoint the registers of the thread we're about to switch to.
1057	 *
1058	 * If the task was using FP, we non-lazily reload both the original and
1059	 * the speculative FP register states.  This is because the kernel
1060	 * doesn't see if/when a TM rollback occurs, so if we take an FP
1061	 * unavailable later, we are unable to determine which set of FP regs
1062	 * need to be restored.
1063	 */
1064	if (!tm_enabled(new))
1065		return;
1066
1067	if (!MSR_TM_ACTIVE(new->thread.regs->msr)){
1068		tm_restore_sprs(&new->thread);
1069		return;
1070	}
 
1071	/* Recheckpoint to restore original checkpointed register state. */
1072	TM_DEBUG("*** tm_recheckpoint of pid %d (new->msr 0x%lx)\n",
1073		 new->pid, new->thread.regs->msr);
1074
1075	tm_recheckpoint(&new->thread);
1076
1077	/*
1078	 * The checkpointed state has been restored but the live state has
1079	 * not, ensure all the math functionality is turned off to trigger
1080	 * restore_math() to reload.
1081	 */
1082	new->thread.regs->msr &= ~(MSR_FP | MSR_VEC | MSR_VSX);
 
 
 
 
 
 
 
 
 
 
 
1083
1084	TM_DEBUG("*** tm_recheckpoint of pid %d complete "
1085		 "(kernel msr 0x%lx)\n",
1086		 new->pid, mfmsr());
1087}
1088
1089static inline void __switch_to_tm(struct task_struct *prev,
1090		struct task_struct *new)
1091{
1092	if (cpu_has_feature(CPU_FTR_TM)) {
1093		if (tm_enabled(prev) || tm_enabled(new))
1094			tm_enable();
1095
1096		if (tm_enabled(prev)) {
1097			prev->thread.load_tm++;
1098			tm_reclaim_task(prev);
1099			if (!MSR_TM_ACTIVE(prev->thread.regs->msr) && prev->thread.load_tm == 0)
1100				prev->thread.regs->msr &= ~MSR_TM;
1101		}
1102
1103		tm_recheckpoint_new_task(new);
1104	}
1105}
1106
1107/*
1108 * This is called if we are on the way out to userspace and the
1109 * TIF_RESTORE_TM flag is set.  It checks if we need to reload
1110 * FP and/or vector state and does so if necessary.
1111 * If userspace is inside a transaction (whether active or
1112 * suspended) and FP/VMX/VSX instructions have ever been enabled
1113 * inside that transaction, then we have to keep them enabled
1114 * and keep the FP/VMX/VSX state loaded while ever the transaction
1115 * continues.  The reason is that if we didn't, and subsequently
1116 * got a FP/VMX/VSX unavailable interrupt inside a transaction,
1117 * we don't know whether it's the same transaction, and thus we
1118 * don't know which of the checkpointed state and the transactional
1119 * state to use.
1120 */
1121void restore_tm_state(struct pt_regs *regs)
1122{
1123	unsigned long msr_diff;
1124
1125	/*
1126	 * This is the only moment we should clear TIF_RESTORE_TM as
1127	 * it is here that ckpt_regs.msr and pt_regs.msr become the same
1128	 * again, anything else could lead to an incorrect ckpt_msr being
1129	 * saved and therefore incorrect signal contexts.
1130	 */
1131	clear_thread_flag(TIF_RESTORE_TM);
1132	if (!MSR_TM_ACTIVE(regs->msr))
1133		return;
1134
1135	msr_diff = current->thread.ckpt_regs.msr & ~regs->msr;
1136	msr_diff &= MSR_FP | MSR_VEC | MSR_VSX;
1137
1138	/* Ensure that restore_math() will restore */
1139	if (msr_diff & MSR_FP)
1140		current->thread.load_fp = 1;
1141#ifdef CONFIG_ALTIVEC
1142	if (cpu_has_feature(CPU_FTR_ALTIVEC) && msr_diff & MSR_VEC)
1143		current->thread.load_vec = 1;
1144#endif
1145	restore_math(regs);
1146
1147	regs_set_return_msr(regs, regs->msr | msr_diff);
1148}
1149
1150#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
1151#define tm_recheckpoint_new_task(new)
1152#define __switch_to_tm(prev, new)
1153void tm_reclaim_current(uint8_t cause) {}
1154#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1155
1156static inline void save_sprs(struct thread_struct *t)
1157{
1158#ifdef CONFIG_ALTIVEC
1159	if (cpu_has_feature(CPU_FTR_ALTIVEC))
1160		t->vrsave = mfspr(SPRN_VRSAVE);
1161#endif
1162#ifdef CONFIG_SPE
1163	if (cpu_has_feature(CPU_FTR_SPE))
1164		t->spefscr = mfspr(SPRN_SPEFSCR);
1165#endif
1166#ifdef CONFIG_PPC_BOOK3S_64
1167	if (cpu_has_feature(CPU_FTR_DSCR))
1168		t->dscr = mfspr(SPRN_DSCR);
1169
1170	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
1171		t->bescr = mfspr(SPRN_BESCR);
1172		t->ebbhr = mfspr(SPRN_EBBHR);
1173		t->ebbrr = mfspr(SPRN_EBBRR);
1174
1175		t->fscr = mfspr(SPRN_FSCR);
1176
1177		/*
1178		 * Note that the TAR is not available for use in the kernel.
1179		 * (To provide this, the TAR should be backed up/restored on
1180		 * exception entry/exit instead, and be in pt_regs.  FIXME,
1181		 * this should be in pt_regs anyway (for debug).)
1182		 */
1183		t->tar = mfspr(SPRN_TAR);
1184	}
1185
1186	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
1187		t->hashkeyr = mfspr(SPRN_HASHKEYR);
1188#endif
1189}
1190
1191#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
1192void kvmppc_save_user_regs(void)
1193{
1194	unsigned long usermsr;
1195
1196	if (!current->thread.regs)
1197		return;
1198
1199	usermsr = current->thread.regs->msr;
1200
1201	/* Caller has enabled FP/VEC/VSX/TM in MSR */
1202	if (usermsr & MSR_FP)
1203		__giveup_fpu(current);
1204	if (usermsr & MSR_VEC)
1205		__giveup_altivec(current);
1206
1207#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1208	if (usermsr & MSR_TM) {
1209		current->thread.tm_tfhar = mfspr(SPRN_TFHAR);
1210		current->thread.tm_tfiar = mfspr(SPRN_TFIAR);
1211		current->thread.tm_texasr = mfspr(SPRN_TEXASR);
1212		current->thread.regs->msr &= ~MSR_TM;
1213	}
1214#endif
1215}
1216EXPORT_SYMBOL_GPL(kvmppc_save_user_regs);
1217
1218void kvmppc_save_current_sprs(void)
1219{
1220	save_sprs(&current->thread);
1221}
1222EXPORT_SYMBOL_GPL(kvmppc_save_current_sprs);
1223#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
1224
1225static inline void restore_sprs(struct thread_struct *old_thread,
1226				struct thread_struct *new_thread)
1227{
1228#ifdef CONFIG_ALTIVEC
1229	if (cpu_has_feature(CPU_FTR_ALTIVEC) &&
1230	    old_thread->vrsave != new_thread->vrsave)
1231		mtspr(SPRN_VRSAVE, new_thread->vrsave);
1232#endif
1233#ifdef CONFIG_SPE
1234	if (cpu_has_feature(CPU_FTR_SPE) &&
1235	    old_thread->spefscr != new_thread->spefscr)
1236		mtspr(SPRN_SPEFSCR, new_thread->spefscr);
1237#endif
1238#ifdef CONFIG_PPC_BOOK3S_64
1239	if (cpu_has_feature(CPU_FTR_DSCR)) {
1240		u64 dscr = get_paca()->dscr_default;
1241		if (new_thread->dscr_inherit)
 
 
1242			dscr = new_thread->dscr;
 
 
1243
1244		if (old_thread->dscr != dscr)
1245			mtspr(SPRN_DSCR, dscr);
 
 
 
1246	}
1247
1248	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
1249		if (old_thread->bescr != new_thread->bescr)
1250			mtspr(SPRN_BESCR, new_thread->bescr);
1251		if (old_thread->ebbhr != new_thread->ebbhr)
1252			mtspr(SPRN_EBBHR, new_thread->ebbhr);
1253		if (old_thread->ebbrr != new_thread->ebbrr)
1254			mtspr(SPRN_EBBRR, new_thread->ebbrr);
1255
1256		if (old_thread->fscr != new_thread->fscr)
1257			mtspr(SPRN_FSCR, new_thread->fscr);
1258
1259		if (old_thread->tar != new_thread->tar)
1260			mtspr(SPRN_TAR, new_thread->tar);
1261	}
1262
1263	if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
1264	    old_thread->tidr != new_thread->tidr)
1265		mtspr(SPRN_TIDR, new_thread->tidr);
1266
1267	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) &&
1268	    old_thread->hashkeyr != new_thread->hashkeyr)
1269		mtspr(SPRN_HASHKEYR, new_thread->hashkeyr);
1270#endif
1271
1272}
1273
1274struct task_struct *__switch_to(struct task_struct *prev,
1275	struct task_struct *new)
1276{
1277	struct thread_struct *new_thread, *old_thread;
1278	struct task_struct *last;
1279#ifdef CONFIG_PPC_64S_HASH_MMU
1280	struct ppc64_tlb_batch *batch;
1281#endif
1282
1283	new_thread = &new->thread;
1284	old_thread = &current->thread;
1285
1286	WARN_ON(!irqs_disabled());
1287
1288#ifdef CONFIG_PPC_64S_HASH_MMU
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1289	batch = this_cpu_ptr(&ppc64_tlb_batch);
1290	if (batch->active) {
1291		current_thread_info()->local_flags |= _TLF_LAZY_MMU;
1292		if (batch->index)
1293			__flush_tlb_pending(batch);
1294		batch->active = 0;
1295	}
1296
1297	/*
1298	 * On POWER9 the copy-paste buffer can only paste into
1299	 * foreign real addresses, so unprivileged processes can not
1300	 * see the data or use it in any way unless they have
1301	 * foreign real mappings. If the new process has the foreign
1302	 * real address mappings, we must issue a cp_abort to clear
1303	 * any state and prevent snooping, corruption or a covert
1304	 * channel. ISA v3.1 supports paste into local memory.
1305	 */
1306	if (new->mm && (cpu_has_feature(CPU_FTR_ARCH_31) ||
1307			atomic_read(&new->mm->context.vas_windows)))
1308		asm volatile(PPC_CP_ABORT);
1309#endif /* CONFIG_PPC_BOOK3S_64 */
1310
1311#ifdef CONFIG_PPC_ADV_DEBUG_REGS
1312	switch_booke_debug_regs(&new->thread.debug);
1313#else
1314/*
1315 * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
1316 * schedule DABR
1317 */
1318#ifndef CONFIG_HAVE_HW_BREAKPOINT
1319	switch_hw_breakpoint(new);
 
1320#endif /* CONFIG_HAVE_HW_BREAKPOINT */
1321#endif
1322
1323	/*
1324	 * We need to save SPRs before treclaim/trecheckpoint as these will
1325	 * change a number of them.
1326	 */
1327	save_sprs(&prev->thread);
1328
 
 
1329	/* Save FPU, Altivec, VSX and SPE state */
1330	giveup_all(prev);
1331
1332	__switch_to_tm(prev, new);
 
 
 
 
 
1333
1334	if (!radix_enabled()) {
1335		/*
1336		 * We can't take a PMU exception inside _switch() since there
1337		 * is a window where the kernel stack SLB and the kernel stack
1338		 * are out of sync. Hard disable here.
1339		 */
1340		hard_irq_disable();
1341	}
1342
1343	/*
1344	 * Call restore_sprs() and set_return_regs_changed() before calling
1345	 * _switch(). If we move it after _switch() then we miss out on calling
1346	 * it for new tasks. The reason for this is we manually create a stack
1347	 * frame for new tasks that directly returns through ret_from_fork() or
1348	 * ret_from_kernel_thread(). See copy_thread() for details.
1349	 */
1350	restore_sprs(old_thread, new_thread);
1351
1352	set_return_regs_changed(); /* _switch changes stack (and regs) */
1353
1354	if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
1355		kuap_assert_locked();
1356
1357	last = _switch(old_thread, new_thread);
1358
1359	/*
1360	 * Nothing after _switch will be run for newly created tasks,
1361	 * because they switch directly to ret_from_fork/ret_from_kernel_thread
1362	 * etc. Code added here should have a comment explaining why that is
1363	 * okay.
1364	 */
1365
1366#ifdef CONFIG_PPC_BOOK3S_64
1367#ifdef CONFIG_PPC_64S_HASH_MMU
1368	/*
1369	 * This applies to a process that was context switched while inside
1370	 * arch_enter_lazy_mmu_mode(), to re-activate the batch that was
1371	 * deactivated above, before _switch(). This will never be the case
1372	 * for new tasks.
1373	 */
1374	if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
1375		current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
1376		batch = this_cpu_ptr(&ppc64_tlb_batch);
1377		batch->active = 1;
1378	}
1379#endif
1380
1381	/*
1382	 * Math facilities are masked out of the child MSR in copy_thread.
1383	 * A new task does not need to restore_math because it will
1384	 * demand fault them.
1385	 */
1386	if (current->thread.regs)
1387		restore_math(current->thread.regs);
1388#endif /* CONFIG_PPC_BOOK3S_64 */
1389
1390	return last;
1391}
1392
1393#define NR_INSN_TO_PRINT	16
1394
1395static void show_instructions(struct pt_regs *regs)
1396{
1397	int i;
1398	unsigned long nip = regs->nip;
1399	unsigned long pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
1400
1401	printk("Code: ");
1402
1403	/*
1404	 * If we were executing with the MMU off for instructions, adjust pc
1405	 * rather than printing XXXXXXXX.
1406	 */
1407	if (!IS_ENABLED(CONFIG_BOOKE) && !(regs->msr & MSR_IR)) {
1408		pc = (unsigned long)phys_to_virt(pc);
1409		nip = (unsigned long)phys_to_virt(regs->nip);
1410	}
1411
1412	for (i = 0; i < NR_INSN_TO_PRINT; i++) {
1413		int instr;
1414
1415		if (get_kernel_nofault(instr, (const void *)pc)) {
1416			pr_cont("XXXXXXXX ");
 
 
 
 
 
 
 
 
 
 
 
 
1417		} else {
1418			if (nip == pc)
1419				pr_cont("<%08x> ", instr);
1420			else
1421				pr_cont("%08x ", instr);
1422		}
1423
1424		pc += sizeof(int);
1425	}
1426
1427	pr_cont("\n");
1428}
1429
1430void show_user_instructions(struct pt_regs *regs)
1431{
1432	unsigned long pc;
1433	int n = NR_INSN_TO_PRINT;
1434	struct seq_buf s;
1435	char buf[96]; /* enough for 8 times 9 + 2 chars */
1436
1437	pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
1438
1439	seq_buf_init(&s, buf, sizeof(buf));
1440
1441	while (n) {
1442		int i;
1443
1444		seq_buf_clear(&s);
1445
1446		for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) {
1447			int instr;
1448
1449			if (copy_from_user_nofault(&instr, (void __user *)pc,
1450					sizeof(instr))) {
1451				seq_buf_printf(&s, "XXXXXXXX ");
1452				continue;
1453			}
1454			seq_buf_printf(&s, regs->nip == pc ? "<%08x> " : "%08x ", instr);
1455		}
1456
1457		if (!seq_buf_has_overflowed(&s))
1458			pr_info("%s[%d]: code: %s\n", current->comm,
1459				current->pid, s.buffer);
1460	}
1461}
1462
1463struct regbit {
1464	unsigned long bit;
1465	const char *name;
1466};
1467
1468static struct regbit msr_bits[] = {
1469#if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
1470	{MSR_SF,	"SF"},
1471	{MSR_HV,	"HV"},
1472#endif
1473	{MSR_VEC,	"VEC"},
1474	{MSR_VSX,	"VSX"},
1475#ifdef CONFIG_BOOKE
1476	{MSR_CE,	"CE"},
1477#endif
1478	{MSR_EE,	"EE"},
1479	{MSR_PR,	"PR"},
1480	{MSR_FP,	"FP"},
1481	{MSR_ME,	"ME"},
1482#ifdef CONFIG_BOOKE
1483	{MSR_DE,	"DE"},
1484#else
1485	{MSR_SE,	"SE"},
1486	{MSR_BE,	"BE"},
1487#endif
1488	{MSR_IR,	"IR"},
1489	{MSR_DR,	"DR"},
1490	{MSR_PMM,	"PMM"},
1491#ifndef CONFIG_BOOKE
1492	{MSR_RI,	"RI"},
1493	{MSR_LE,	"LE"},
1494#endif
1495	{0,		NULL}
1496};
1497
1498static void print_bits(unsigned long val, struct regbit *bits, const char *sep)
1499{
1500	const char *s = "";
1501
1502	for (; bits->bit; ++bits)
1503		if (val & bits->bit) {
1504			pr_cont("%s%s", s, bits->name);
1505			s = sep;
1506		}
1507}
1508
1509#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1510static struct regbit msr_tm_bits[] = {
1511	{MSR_TS_T,	"T"},
1512	{MSR_TS_S,	"S"},
1513	{MSR_TM,	"E"},
1514	{0,		NULL}
1515};
1516
1517static void print_tm_bits(unsigned long val)
1518{
1519/*
1520 * This only prints something if at least one of the TM bit is set.
1521 * Inside the TM[], the output means:
1522 *   E: Enabled		(bit 32)
1523 *   S: Suspended	(bit 33)
1524 *   T: Transactional	(bit 34)
1525 */
1526	if (val & (MSR_TM | MSR_TS_S | MSR_TS_T)) {
1527		pr_cont(",TM[");
1528		print_bits(val, msr_tm_bits, "");
1529		pr_cont("]");
1530	}
1531}
1532#else
1533static void print_tm_bits(unsigned long val) {}
1534#endif
1535
1536static void print_msr_bits(unsigned long val)
1537{
1538	pr_cont("<");
1539	print_bits(val, msr_bits, ",");
1540	print_tm_bits(val);
1541	pr_cont(">");
1542}
1543
1544#ifdef CONFIG_PPC64
1545#define REG		"%016lx"
1546#define REGS_PER_LINE	4
 
1547#else
1548#define REG		"%08lx"
1549#define REGS_PER_LINE	8
 
1550#endif
1551
1552static void __show_regs(struct pt_regs *regs)
1553{
1554	int i, trap;
1555
1556	printk("NIP:  "REG" LR: "REG" CTR: "REG"\n",
 
 
1557	       regs->nip, regs->link, regs->ctr);
1558	printk("REGS: %px TRAP: %04lx   %s  (%s)\n",
1559	       regs, regs->trap, print_tainted(), init_utsname()->release);
1560	printk("MSR:  "REG" ", regs->msr);
1561	print_msr_bits(regs->msr);
1562	pr_cont("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
1563	trap = TRAP(regs);
1564	if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR))
1565		pr_cont("CFAR: "REG" ", regs->orig_gpr3);
1566	if (trap == INTERRUPT_MACHINE_CHECK ||
1567	    trap == INTERRUPT_DATA_STORAGE ||
1568	    trap == INTERRUPT_ALIGNMENT) {
1569		if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE))
1570			pr_cont("DEAR: "REG" ESR: "REG" ", regs->dear, regs->esr);
1571		else
1572			pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
1573	}
1574
1575#ifdef CONFIG_PPC64
1576	pr_cont("IRQMASK: %lx ", regs->softe);
1577#endif
1578#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1579	if (MSR_TM_ACTIVE(regs->msr))
1580		pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
1581#endif
1582
1583	for (i = 0;  i < 32;  i++) {
1584		if ((i % REGS_PER_LINE) == 0)
1585			pr_cont("\nGPR%02d: ", i);
1586		pr_cont(REG " ", regs->gpr[i]);
 
 
1587	}
1588	pr_cont("\n");
 
1589	/*
1590	 * Lookup NIP late so we have the best change of getting the
1591	 * above info out without failing
1592	 */
1593	if (IS_ENABLED(CONFIG_KALLSYMS)) {
1594		printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1595		printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1596	}
 
 
1597}
1598
1599void show_regs(struct pt_regs *regs)
1600{
1601	show_regs_print_info(KERN_DEFAULT);
1602	__show_regs(regs);
1603	show_stack(current, (unsigned long *) regs->gpr[1], KERN_DEFAULT);
1604	if (!user_mode(regs))
1605		show_instructions(regs);
1606}
1607
1608void flush_thread(void)
1609{
1610#ifdef CONFIG_HAVE_HW_BREAKPOINT
1611	flush_ptrace_hw_breakpoint(current);
1612#else /* CONFIG_HAVE_HW_BREAKPOINT */
1613	set_debug_reg_defaults(&current->thread);
1614#endif /* CONFIG_HAVE_HW_BREAKPOINT */
1615}
1616
1617void arch_setup_new_exec(void)
1618{
1619
1620#ifdef CONFIG_PPC_BOOK3S_64
1621	if (!radix_enabled())
1622		hash__setup_new_exec();
1623#endif
1624	/*
1625	 * If we exec out of a kernel thread then thread.regs will not be
1626	 * set.  Do it now.
1627	 */
1628	if (!current->thread.regs) {
1629		struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
1630		current->thread.regs = regs - 1;
1631	}
1632
1633#ifdef CONFIG_PPC_MEM_KEYS
1634	current->thread.regs->amr  = default_amr;
1635	current->thread.regs->iamr  = default_iamr;
1636#endif
1637}
1638
1639#ifdef CONFIG_PPC64
1640/*
1641 * Assign a TIDR (thread ID) for task @t and set it in the thread
1642 * structure. For now, we only support setting TIDR for 'current' task.
1643 *
1644 * Since the TID value is a truncated form of it PID, it is possible
1645 * (but unlikely) for 2 threads to have the same TID. In the unlikely event
1646 * that 2 threads share the same TID and are waiting, one of the following
1647 * cases will happen:
1648 *
1649 * 1. The correct thread is running, the wrong thread is not
1650 * In this situation, the correct thread is woken and proceeds to pass it's
1651 * condition check.
1652 *
1653 * 2. Neither threads are running
1654 * In this situation, neither thread will be woken. When scheduled, the waiting
1655 * threads will execute either a wait, which will return immediately, followed
1656 * by a condition check, which will pass for the correct thread and fail
1657 * for the wrong thread, or they will execute the condition check immediately.
1658 *
1659 * 3. The wrong thread is running, the correct thread is not
1660 * The wrong thread will be woken, but will fail it's condition check and
1661 * re-execute wait. The correct thread, when scheduled, will execute either
1662 * it's condition check (which will pass), or wait, which returns immediately
1663 * when called the first time after the thread is scheduled, followed by it's
1664 * condition check (which will pass).
1665 *
1666 * 4. Both threads are running
1667 * Both threads will be woken. The wrong thread will fail it's condition check
1668 * and execute another wait, while the correct thread will pass it's condition
1669 * check.
1670 *
1671 * @t: the task to set the thread ID for
1672 */
1673int set_thread_tidr(struct task_struct *t)
1674{
1675	if (!cpu_has_feature(CPU_FTR_P9_TIDR))
1676		return -EINVAL;
1677
1678	if (t != current)
1679		return -EINVAL;
1680
1681	if (t->thread.tidr)
1682		return 0;
1683
1684	t->thread.tidr = (u16)task_pid_nr(t);
1685	mtspr(SPRN_TIDR, t->thread.tidr);
1686
1687	return 0;
1688}
1689EXPORT_SYMBOL_GPL(set_thread_tidr);
1690
1691#endif /* CONFIG_PPC64 */
1692
1693/*
1694 * this gets called so that we can store coprocessor state into memory and
1695 * copy the current task into the new thread.
1696 */
1697int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
1698{
1699	flush_all_to_thread(src);
1700	/*
1701	 * Flush TM state out so we can copy it.  __switch_to_tm() does this
1702	 * flush but it removes the checkpointed state from the current CPU and
1703	 * transitions the CPU out of TM mode.  Hence we need to call
1704	 * tm_recheckpoint_new_task() (on the same task) to restore the
1705	 * checkpointed state back and the TM mode.
1706	 *
1707	 * Can't pass dst because it isn't ready. Doesn't matter, passing
1708	 * dst is only important for __switch_to()
1709	 */
1710	__switch_to_tm(src, src);
 
1711
1712	*dst = *src;
1713
1714	clear_task_ebb(dst);
1715
1716	return 0;
1717}
1718
1719static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
1720{
1721#ifdef CONFIG_PPC_64S_HASH_MMU
1722	unsigned long sp_vsid;
1723	unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
1724
1725	if (radix_enabled())
1726		return;
1727
1728	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
1729		sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
1730			<< SLB_VSID_SHIFT_1T;
1731	else
1732		sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
1733			<< SLB_VSID_SHIFT;
1734	sp_vsid |= SLB_VSID_KERNEL | llp;
1735	p->thread.ksp_vsid = sp_vsid;
1736#endif
1737}
1738
1739/*
1740 * Copy a thread..
1741 */
1742
1743/*
1744 * Copy architecture-specific thread state
1745 */
1746int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
1747{
1748	struct pt_regs *kregs; /* Switch frame regs */
1749	extern void ret_from_fork(void);
1750	extern void ret_from_fork_scv(void);
1751	extern void ret_from_kernel_user_thread(void);
1752	extern void start_kernel_thread(void);
1753	void (*f)(void);
1754	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
1755#ifdef CONFIG_HAVE_HW_BREAKPOINT
1756	int i;
1757#endif
1758
1759	klp_init_thread_info(p);
1760
 
 
 
1761	if (unlikely(p->flags & PF_KTHREAD)) {
1762		/* kernel thread */
1763
1764		/* Create initial minimum stack frame. */
1765		sp -= STACK_FRAME_MIN_SIZE;
1766		((unsigned long *)sp)[0] = 0;
1767
1768		f = start_kernel_thread;
 
 
 
 
 
1769		p->thread.regs = NULL;	/* no user register state */
1770		clear_tsk_compat_task(p);
 
1771	} else {
1772		/* user thread */
1773		struct pt_regs *childregs;
1774
1775		/* Create initial user return stack frame. */
1776		sp -= STACK_USER_INT_FRAME_SIZE;
1777		*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
1778
1779		childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS);
1780
1781		if (unlikely(args->fn)) {
1782			/*
1783			 * A user space thread, but it first runs a kernel
1784			 * thread, and then returns as though it had called
1785			 * execve rather than fork, so user regs will be
1786			 * filled in (e.g., by kernel_execve()).
1787			 */
1788			((unsigned long *)sp)[0] = 0;
1789			memset(childregs, 0, sizeof(struct pt_regs));
1790#ifdef CONFIG_PPC64
1791			childregs->softe = IRQS_ENABLED;
1792#endif
1793			f = ret_from_kernel_user_thread;
1794		} else {
1795			struct pt_regs *regs = current_pt_regs();
1796			unsigned long clone_flags = args->flags;
1797			unsigned long usp = args->stack;
1798
1799			/* Copy registers */
1800			*childregs = *regs;
1801			if (usp)
1802				childregs->gpr[1] = usp;
1803			((unsigned long *)sp)[0] = childregs->gpr[1];
1804#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
1805			WARN_ON_ONCE(childregs->softe != IRQS_ENABLED);
1806#endif
1807			if (clone_flags & CLONE_SETTLS) {
1808				unsigned long tls = args->tls;
1809
1810				if (!is_32bit_task())
1811					childregs->gpr[13] = tls;
1812				else
1813					childregs->gpr[2] = tls;
1814			}
1815
1816			if (trap_is_scv(regs))
1817				f = ret_from_fork_scv;
1818			else
1819				f = ret_from_fork;
 
1820		}
1821
1822		childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
1823		p->thread.regs = childregs;
1824	}
 
 
1825
1826	/*
1827	 * The way this works is that at some point in the future
1828	 * some task will call _switch to switch to the new task.
1829	 * That will pop off the stack frame created below and start
1830	 * the new task running at ret_from_fork.  The new task will
1831	 * do some house keeping and then return from the fork or clone
1832	 * system call, using the stack frame created above.
1833	 */
1834	((unsigned long *)sp)[STACK_FRAME_LR_SAVE] = (unsigned long)f;
1835	sp -= STACK_SWITCH_FRAME_SIZE;
1836	((unsigned long *)sp)[0] = sp + STACK_SWITCH_FRAME_SIZE;
1837	kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);
1838	kregs->nip = ppc_function_entry(f);
1839	if (unlikely(args->fn)) {
1840		/*
1841		 * Put kthread fn, arg parameters in non-volatile GPRs in the
1842		 * switch frame so they are loaded by _switch before it returns
1843		 * to ret_from_kernel_thread.
1844		 */
1845		kregs->gpr[14] = ppc_function_entry((void *)args->fn);
1846		kregs->gpr[15] = (unsigned long)args->fn_arg;
1847	}
1848	p->thread.ksp = sp;
1849
 
 
 
1850#ifdef CONFIG_HAVE_HW_BREAKPOINT
1851	for (i = 0; i < nr_wp_slots(); i++)
1852		p->thread.ptrace_bps[i] = NULL;
1853#endif
1854
1855#ifdef CONFIG_PPC_FPU_REGS
1856	p->thread.fp_save_area = NULL;
1857#endif
1858#ifdef CONFIG_ALTIVEC
1859	p->thread.vr_save_area = NULL;
1860#endif
1861#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP)
1862	p->thread.kuap = KUAP_NONE;
1863#endif
1864#if defined(CONFIG_BOOKE_OR_40x) && defined(CONFIG_PPC_KUAP)
1865	p->thread.pid = MMU_NO_CONTEXT;
1866#endif
1867
1868	setup_ksp_vsid(p, sp);
1869
1870#ifdef CONFIG_PPC64 
1871	if (cpu_has_feature(CPU_FTR_DSCR)) {
1872		p->thread.dscr_inherit = current->thread.dscr_inherit;
1873		p->thread.dscr = mfspr(SPRN_DSCR);
1874	}
1875
1876	p->thread.tidr = 0;
1877#endif
1878#ifdef CONFIG_PPC_BOOK3S_64
1879	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
1880		p->thread.hashkeyr = current->thread.hashkeyr;
1881#endif
 
1882	return 0;
1883}
1884
1885void preload_new_slb_context(unsigned long start, unsigned long sp);
1886
1887/*
1888 * Set up a thread for executing a new program
1889 */
1890void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
1891{
1892#ifdef CONFIG_PPC64
1893	unsigned long load_addr = regs->gpr[2];	/* saved by ELF_PLAT_INIT */
1894
1895	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled())
1896		preload_new_slb_context(start, sp);
1897#endif
1898
1899#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1900	/*
1901	 * Clear any transactional state, we're exec()ing. The cause is
1902	 * not important as there will never be a recheckpoint so it's not
1903	 * user visible.
1904	 */
1905	if (MSR_TM_SUSPENDED(mfmsr()))
1906		tm_reclaim_current(0);
1907#endif
 
1908
1909	memset(&regs->gpr[1], 0, sizeof(regs->gpr) - sizeof(regs->gpr[0]));
1910	regs->ctr = 0;
1911	regs->link = 0;
1912	regs->xer = 0;
1913	regs->ccr = 0;
1914	regs->gpr[1] = sp;
1915
 
 
 
 
 
 
 
1916#ifdef CONFIG_PPC32
1917	regs->mq = 0;
1918	regs->nip = start;
1919	regs->msr = MSR_USER;
1920#else
1921	if (!is_32bit_task()) {
1922		unsigned long entry;
1923
1924		if (is_elf2_task()) {
1925			/* Look ma, no function descriptors! */
1926			entry = start;
1927
1928			/*
1929			 * Ulrich says:
1930			 *   The latest iteration of the ABI requires that when
1931			 *   calling a function (at its global entry point),
1932			 *   the caller must ensure r12 holds the entry point
1933			 *   address (so that the function can quickly
1934			 *   establish addressability).
1935			 */
1936			regs->gpr[12] = start;
1937			/* Make sure that's restored on entry to userspace. */
1938			set_thread_flag(TIF_RESTOREALL);
1939		} else {
1940			unsigned long toc;
1941
1942			/* start is a relocated pointer to the function
1943			 * descriptor for the elf _start routine.  The first
1944			 * entry in the function descriptor is the entry
1945			 * address of _start and the second entry is the TOC
1946			 * value we need to use.
1947			 */
1948			__get_user(entry, (unsigned long __user *)start);
1949			__get_user(toc, (unsigned long __user *)start+1);
1950
1951			/* Check whether the e_entry function descriptor entries
1952			 * need to be relocated before we can use them.
1953			 */
1954			if (load_addr != 0) {
1955				entry += load_addr;
1956				toc   += load_addr;
1957			}
1958			regs->gpr[2] = toc;
1959		}
1960		regs_set_return_ip(regs, entry);
1961		regs_set_return_msr(regs, MSR_USER64);
1962	} else {
 
1963		regs->gpr[2] = 0;
1964		regs_set_return_ip(regs, start);
1965		regs_set_return_msr(regs, MSR_USER32);
1966	}
1967
1968#endif
1969#ifdef CONFIG_VSX
1970	current->thread.used_vsr = 0;
1971#endif
1972	current->thread.load_slb = 0;
1973	current->thread.load_fp = 0;
1974#ifdef CONFIG_PPC_FPU_REGS
1975	memset(&current->thread.fp_state, 0, sizeof(current->thread.fp_state));
1976	current->thread.fp_save_area = NULL;
1977#endif
1978#ifdef CONFIG_ALTIVEC
1979	memset(&current->thread.vr_state, 0, sizeof(current->thread.vr_state));
1980	current->thread.vr_state.vscr.u[3] = 0x00010000; /* Java mode disabled */
1981	current->thread.vr_save_area = NULL;
1982	current->thread.vrsave = 0;
1983	current->thread.used_vr = 0;
1984	current->thread.load_vec = 0;
1985#endif /* CONFIG_ALTIVEC */
1986#ifdef CONFIG_SPE
1987	memset(current->thread.evr, 0, sizeof(current->thread.evr));
1988	current->thread.acc = 0;
1989	current->thread.spefscr = 0;
1990	current->thread.used_spe = 0;
1991#endif /* CONFIG_SPE */
1992#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 
 
1993	current->thread.tm_tfhar = 0;
1994	current->thread.tm_texasr = 0;
1995	current->thread.tm_tfiar = 0;
1996	current->thread.load_tm = 0;
1997#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1998#ifdef CONFIG_PPC_BOOK3S_64
1999	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE)) {
2000		current->thread.hashkeyr = get_random_long();
2001		mtspr(SPRN_HASHKEYR, current->thread.hashkeyr);
2002	}
2003#endif /* CONFIG_PPC_BOOK3S_64 */
2004}
2005EXPORT_SYMBOL(start_thread);
2006
2007#define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
2008		| PR_FP_EXC_RES | PR_FP_EXC_INV)
2009
2010int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
2011{
2012	struct pt_regs *regs = tsk->thread.regs;
2013
2014	/* This is a bit hairy.  If we are an SPE enabled  processor
2015	 * (have embedded fp) we store the IEEE exception enable flags in
2016	 * fpexc_mode.  fpexc_mode is also used for setting FP exception
2017	 * mode (asyn, precise, disabled) for 'Classic' FP. */
2018	if (val & PR_FP_EXC_SW_ENABLE) {
 
2019		if (cpu_has_feature(CPU_FTR_SPE)) {
2020			/*
2021			 * When the sticky exception bits are set
2022			 * directly by userspace, it must call prctl
2023			 * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
2024			 * in the existing prctl settings) or
2025			 * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
2026			 * the bits being set).  <fenv.h> functions
2027			 * saving and restoring the whole
2028			 * floating-point environment need to do so
2029			 * anyway to restore the prctl settings from
2030			 * the saved environment.
2031			 */
2032#ifdef CONFIG_SPE
2033			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
2034			tsk->thread.fpexc_mode = val &
2035				(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
2036#endif
2037			return 0;
2038		} else {
2039			return -EINVAL;
2040		}
 
 
 
2041	}
2042
2043	/* on a CONFIG_SPE this does not hurt us.  The bits that
2044	 * __pack_fe01 use do not overlap with bits used for
2045	 * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
2046	 * on CONFIG_SPE implementations are reserved so writing to
2047	 * them does not change anything */
2048	if (val > PR_FP_EXC_PRECISE)
2049		return -EINVAL;
2050	tsk->thread.fpexc_mode = __pack_fe01(val);
2051	if (regs != NULL && (regs->msr & MSR_FP) != 0) {
2052		regs_set_return_msr(regs, (regs->msr & ~(MSR_FE0|MSR_FE1))
2053						| tsk->thread.fpexc_mode);
2054	}
2055	return 0;
2056}
2057
2058int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
2059{
2060	unsigned int val = 0;
2061
2062	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) {
 
2063		if (cpu_has_feature(CPU_FTR_SPE)) {
2064			/*
2065			 * When the sticky exception bits are set
2066			 * directly by userspace, it must call prctl
2067			 * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
2068			 * in the existing prctl settings) or
2069			 * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
2070			 * the bits being set).  <fenv.h> functions
2071			 * saving and restoring the whole
2072			 * floating-point environment need to do so
2073			 * anyway to restore the prctl settings from
2074			 * the saved environment.
2075			 */
2076#ifdef CONFIG_SPE
2077			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
2078			val = tsk->thread.fpexc_mode;
2079#endif
2080		} else
2081			return -EINVAL;
2082	} else {
 
 
 
2083		val = __unpack_fe01(tsk->thread.fpexc_mode);
2084	}
2085	return put_user(val, (unsigned int __user *) adr);
2086}
2087
2088int set_endian(struct task_struct *tsk, unsigned int val)
2089{
2090	struct pt_regs *regs = tsk->thread.regs;
2091
2092	if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
2093	    (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
2094		return -EINVAL;
2095
2096	if (regs == NULL)
2097		return -EINVAL;
2098
2099	if (val == PR_ENDIAN_BIG)
2100		regs_set_return_msr(regs, regs->msr & ~MSR_LE);
2101	else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
2102		regs_set_return_msr(regs, regs->msr | MSR_LE);
2103	else
2104		return -EINVAL;
2105
2106	return 0;
2107}
2108
2109int get_endian(struct task_struct *tsk, unsigned long adr)
2110{
2111	struct pt_regs *regs = tsk->thread.regs;
2112	unsigned int val;
2113
2114	if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
2115	    !cpu_has_feature(CPU_FTR_REAL_LE))
2116		return -EINVAL;
2117
2118	if (regs == NULL)
2119		return -EINVAL;
2120
2121	if (regs->msr & MSR_LE) {
2122		if (cpu_has_feature(CPU_FTR_REAL_LE))
2123			val = PR_ENDIAN_LITTLE;
2124		else
2125			val = PR_ENDIAN_PPC_LITTLE;
2126	} else
2127		val = PR_ENDIAN_BIG;
2128
2129	return put_user(val, (unsigned int __user *)adr);
2130}
2131
2132int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
2133{
2134	tsk->thread.align_ctl = val;
2135	return 0;
2136}
2137
2138int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
2139{
2140	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
2141}
2142
2143static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
2144				  unsigned long nbytes)
2145{
2146	unsigned long stack_page;
2147	unsigned long cpu = task_cpu(p);
2148
2149	if (!hardirq_ctx[cpu] || !softirq_ctx[cpu])
2150		return 0;
2151
2152	stack_page = (unsigned long)hardirq_ctx[cpu];
2153	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2154		return 1;
2155
2156	stack_page = (unsigned long)softirq_ctx[cpu];
2157	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2158		return 1;
2159
2160	return 0;
2161}
2162
2163static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
2164					unsigned long nbytes)
2165{
2166#ifdef CONFIG_PPC64
2167	unsigned long stack_page;
2168	unsigned long cpu = task_cpu(p);
2169
2170	if (!paca_ptrs)
2171		return 0;
2172
2173	if (!paca_ptrs[cpu]->emergency_sp)
2174		return 0;
2175
2176# ifdef CONFIG_PPC_BOOK3S_64
2177	if (!paca_ptrs[cpu]->nmi_emergency_sp || !paca_ptrs[cpu]->mc_emergency_sp)
2178		return 0;
2179#endif
2180
2181	stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE;
2182	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2183		return 1;
2184
2185# ifdef CONFIG_PPC_BOOK3S_64
2186	stack_page = (unsigned long)paca_ptrs[cpu]->nmi_emergency_sp - THREAD_SIZE;
2187	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2188		return 1;
2189
2190	stack_page = (unsigned long)paca_ptrs[cpu]->mc_emergency_sp - THREAD_SIZE;
2191	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2192		return 1;
2193# endif
2194#endif
2195
2196	return 0;
2197}
2198
2199/*
2200 * validate the stack frame of a particular minimum size, used for when we are
2201 * looking at a certain object in the stack beyond the minimum.
2202 */
2203int validate_sp_size(unsigned long sp, struct task_struct *p,
2204		     unsigned long nbytes)
2205{
2206	unsigned long stack_page = (unsigned long)task_stack_page(p);
2207
2208	if (sp < THREAD_SIZE)
2209		return 0;
2210
2211	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2212		return 1;
2213
2214	if (valid_irq_stack(sp, p, nbytes))
2215		return 1;
2216
2217	return valid_emergency_stack(sp, p, nbytes);
2218}
2219
2220int validate_sp(unsigned long sp, struct task_struct *p)
2221{
2222	return validate_sp_size(sp, p, STACK_FRAME_MIN_SIZE);
2223}
2224
2225static unsigned long ___get_wchan(struct task_struct *p)
2226{
2227	unsigned long ip, sp;
2228	int count = 0;
2229
 
 
 
2230	sp = p->thread.ksp;
2231	if (!validate_sp(sp, p))
2232		return 0;
2233
2234	do {
2235		sp = READ_ONCE_NOCHECK(*(unsigned long *)sp);
2236		if (!validate_sp(sp, p) || task_is_running(p))
2237			return 0;
2238		if (count > 0) {
2239			ip = READ_ONCE_NOCHECK(((unsigned long *)sp)[STACK_FRAME_LR_SAVE]);
2240			if (!in_sched_functions(ip))
2241				return ip;
2242		}
2243	} while (count++ < 16);
2244	return 0;
2245}
2246
2247unsigned long __get_wchan(struct task_struct *p)
2248{
2249	unsigned long ret;
2250
2251	if (!try_get_task_stack(p))
2252		return 0;
2253
2254	ret = ___get_wchan(p);
2255
2256	put_task_stack(p);
2257
2258	return ret;
2259}
2260
2261static bool empty_user_regs(struct pt_regs *regs, struct task_struct *tsk)
2262{
2263	unsigned long stack_page;
2264
2265	// A non-empty pt_regs should never have a zero MSR or TRAP value.
2266	if (regs->msr || regs->trap)
2267		return false;
2268
2269	// Check it sits at the very base of the stack
2270	stack_page = (unsigned long)task_stack_page(tsk);
2271	if ((unsigned long)(regs + 1) != stack_page + THREAD_SIZE)
2272		return false;
2273
2274	return true;
2275}
2276
2277static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
2278
2279void __no_sanitize_address show_stack(struct task_struct *tsk,
2280				      unsigned long *stack,
2281				      const char *loglvl)
2282{
2283	unsigned long sp, ip, lr, newsp;
2284	int count = 0;
2285	int firstframe = 1;
2286	unsigned long ret_addr;
2287	int ftrace_idx = 0;
 
 
 
2288
 
2289	if (tsk == NULL)
2290		tsk = current;
2291
2292	if (!try_get_task_stack(tsk))
2293		return;
2294
2295	sp = (unsigned long) stack;
2296	if (sp == 0) {
2297		if (tsk == current)
2298			sp = current_stack_frame();
2299		else
2300			sp = tsk->thread.ksp;
2301	}
2302
2303	lr = 0;
2304	printk("%sCall Trace:\n", loglvl);
2305	do {
2306		if (!validate_sp(sp, tsk))
2307			break;
2308
2309		stack = (unsigned long *) sp;
2310		newsp = stack[0];
2311		ip = stack[STACK_FRAME_LR_SAVE];
2312		if (!firstframe || ip != lr) {
2313			printk("%s["REG"] ["REG"] %pS",
2314				loglvl, sp, ip, (void *)ip);
2315			ret_addr = ftrace_graph_ret_addr(current,
2316						&ftrace_idx, ip, stack);
2317			if (ret_addr != ip)
2318				pr_cont(" (%pS)", (void *)ret_addr);
 
 
2319			if (firstframe)
2320				pr_cont(" (unreliable)");
2321			pr_cont("\n");
2322		}
2323		firstframe = 0;
2324
2325		/*
2326		 * See if this is an exception frame.
2327		 * We look for the "regs" marker in the current frame.
2328		 *
2329		 * STACK_SWITCH_FRAME_SIZE being the smallest frame that
2330		 * could hold a pt_regs, if that does not fit then it can't
2331		 * have regs.
2332		 */
2333		if (validate_sp_size(sp, tsk, STACK_SWITCH_FRAME_SIZE)
2334		    && stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
2335			struct pt_regs *regs = (struct pt_regs *)
2336				(sp + STACK_INT_FRAME_REGS);
2337
2338			lr = regs->link;
2339			printk("%s--- interrupt: %lx at %pS\n",
2340			       loglvl, regs->trap, (void *)regs->nip);
2341
2342			// Detect the case of an empty pt_regs at the very base
2343			// of the stack and suppress showing it in full.
2344			if (!empty_user_regs(regs, tsk)) {
2345				__show_regs(regs);
2346				printk("%s--- interrupt: %lx\n", loglvl, regs->trap);
2347			}
2348
2349			firstframe = 1;
2350		}
2351
2352		sp = newsp;
2353	} while (count++ < kstack_depth_to_print);
2354
2355	put_task_stack(tsk);
2356}
2357
2358#ifdef CONFIG_PPC64
2359/* Called with hard IRQs off */
2360void notrace __ppc64_runlatch_on(void)
2361{
2362	struct thread_info *ti = current_thread_info();
 
2363
2364	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
2365		/*
2366		 * Least significant bit (RUN) is the only writable bit of
2367		 * the CTRL register, so we can avoid mfspr. 2.06 is not the
2368		 * earliest ISA where this is the case, but it's convenient.
2369		 */
2370		mtspr(SPRN_CTRLT, CTRL_RUNLATCH);
2371	} else {
2372		unsigned long ctrl;
2373
2374		/*
2375		 * Some architectures (e.g., Cell) have writable fields other
2376		 * than RUN, so do the read-modify-write.
2377		 */
2378		ctrl = mfspr(SPRN_CTRLF);
2379		ctrl |= CTRL_RUNLATCH;
2380		mtspr(SPRN_CTRLT, ctrl);
2381	}
2382
2383	ti->local_flags |= _TLF_RUNLATCH;
2384}
2385
2386/* Called with hard IRQs off */
2387void notrace __ppc64_runlatch_off(void)
2388{
2389	struct thread_info *ti = current_thread_info();
 
2390
2391	ti->local_flags &= ~_TLF_RUNLATCH;
2392
2393	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
2394		mtspr(SPRN_CTRLT, 0);
2395	} else {
2396		unsigned long ctrl;
2397
2398		ctrl = mfspr(SPRN_CTRLF);
2399		ctrl &= ~CTRL_RUNLATCH;
2400		mtspr(SPRN_CTRLT, ctrl);
2401	}
2402}
2403#endif /* CONFIG_PPC64 */
2404
2405unsigned long arch_align_stack(unsigned long sp)
2406{
2407	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
2408		sp -= get_random_u32_below(PAGE_SIZE);
2409	return sp & ~0xf;
2410}