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/text-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
 
 
  75#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  76/*
  77 * Are we running in "Suspend disabled" mode? If so we have to block any
  78 * sigreturn that would get us into suspended state, and we also warn in some
  79 * other paths that we should never reach with suspend disabled.
  80 */
  81bool tm_suspend_disabled __ro_after_init = false;
  82
  83static void check_if_tm_restore_required(struct task_struct *tsk)
  84{
  85	/*
  86	 * If we are saving the current thread's registers, and the
  87	 * thread is in a transactional state, set the TIF_RESTORE_TM
  88	 * bit so that we know to restore the registers before
  89	 * returning to userspace.
  90	 */
  91	if (tsk == current && tsk->thread.regs &&
  92	    MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
  93	    !test_thread_flag(TIF_RESTORE_TM)) {
  94		regs_set_return_msr(&tsk->thread.ckpt_regs,
  95						tsk->thread.regs->msr);
  96		set_thread_flag(TIF_RESTORE_TM);
  97	}
  98}
  99
 100#else
 101static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
 102#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 103
 104bool strict_msr_control;
 105EXPORT_SYMBOL(strict_msr_control);
 106
 107static int __init enable_strict_msr_control(char *str)
 108{
 109	strict_msr_control = true;
 110	pr_info("Enabling strict facility control\n");
 111
 112	return 0;
 113}
 114early_param("ppc_strict_facility_enable", enable_strict_msr_control);
 115
 116/* notrace because it's called by restore_math */
 117unsigned long notrace msr_check_and_set(unsigned long bits)
 118{
 119	unsigned long oldmsr = mfmsr();
 120	unsigned long newmsr;
 121
 122	newmsr = oldmsr | bits;
 123
 124	if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
 125		newmsr |= MSR_VSX;
 126
 127	if (oldmsr != newmsr)
 128		newmsr = mtmsr_isync_irqsafe(newmsr);
 129
 130	return newmsr;
 131}
 132EXPORT_SYMBOL_GPL(msr_check_and_set);
 133
 134/* notrace because it's called by restore_math */
 135void notrace __msr_check_and_clear(unsigned long bits)
 136{
 137	unsigned long oldmsr = mfmsr();
 138	unsigned long newmsr;
 139
 140	newmsr = oldmsr & ~bits;
 141
 142	if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP))
 143		newmsr &= ~MSR_VSX;
 144
 145	if (oldmsr != newmsr)
 146		mtmsr_isync_irqsafe(newmsr);
 147}
 148EXPORT_SYMBOL(__msr_check_and_clear);
 149
 150#ifdef CONFIG_PPC_FPU
 151static void __giveup_fpu(struct task_struct *tsk)
 152{
 153	unsigned long msr;
 154
 155	save_fpu(tsk);
 156	msr = tsk->thread.regs->msr;
 157	msr &= ~(MSR_FP|MSR_FE0|MSR_FE1);
 158	if (cpu_has_feature(CPU_FTR_VSX))
 159		msr &= ~MSR_VSX;
 160	regs_set_return_msr(tsk->thread.regs, msr);
 161}
 162
 163void giveup_fpu(struct task_struct *tsk)
 164{
 165	check_if_tm_restore_required(tsk);
 166
 167	msr_check_and_set(MSR_FP);
 168	__giveup_fpu(tsk);
 169	msr_check_and_clear(MSR_FP);
 170}
 171EXPORT_SYMBOL(giveup_fpu);
 172
 173/*
 174 * Make sure the floating-point register state in the
 175 * the thread_struct is up to date for task tsk.
 176 */
 177void flush_fp_to_thread(struct task_struct *tsk)
 178{
 179	if (tsk->thread.regs) {
 180		/*
 181		 * We need to disable preemption here because if we didn't,
 182		 * another process could get scheduled after the regs->msr
 183		 * test but before we have finished saving the FP registers
 184		 * to the thread_struct.  That process could take over the
 185		 * FPU, and then when we get scheduled again we would store
 186		 * bogus values for the remaining FP registers.
 187		 */
 188		preempt_disable();
 189		if (tsk->thread.regs->msr & MSR_FP) {
 190			/*
 191			 * This should only ever be called for current or
 192			 * for a stopped child process.  Since we save away
 193			 * the FP register state on context switch,
 194			 * there is something wrong if a stopped child appears
 195			 * to still have its FP state in the CPU registers.
 196			 */
 197			BUG_ON(tsk != current);
 198			giveup_fpu(tsk);
 199		}
 200		preempt_enable();
 201	}
 202}
 203EXPORT_SYMBOL_GPL(flush_fp_to_thread);
 204
 205void enable_kernel_fp(void)
 206{
 207	unsigned long cpumsr;
 208
 209	WARN_ON(preemptible());
 210
 211	cpumsr = msr_check_and_set(MSR_FP);
 212
 213	if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
 214		check_if_tm_restore_required(current);
 215		/*
 216		 * If a thread has already been reclaimed then the
 217		 * checkpointed registers are on the CPU but have definitely
 218		 * been saved by the reclaim code. Don't need to and *cannot*
 219		 * giveup as this would save  to the 'live' structure not the
 220		 * checkpointed structure.
 221		 */
 222		if (!MSR_TM_ACTIVE(cpumsr) &&
 223		     MSR_TM_ACTIVE(current->thread.regs->msr))
 224			return;
 225		__giveup_fpu(current);
 226	}
 227}
 228EXPORT_SYMBOL(enable_kernel_fp);
 229#else
 230static inline void __giveup_fpu(struct task_struct *tsk) { }
 231#endif /* CONFIG_PPC_FPU */
 232
 233#ifdef CONFIG_ALTIVEC
 234static void __giveup_altivec(struct task_struct *tsk)
 235{
 236	unsigned long msr;
 237
 238	save_altivec(tsk);
 239	msr = tsk->thread.regs->msr;
 240	msr &= ~MSR_VEC;
 241	if (cpu_has_feature(CPU_FTR_VSX))
 242		msr &= ~MSR_VSX;
 243	regs_set_return_msr(tsk->thread.regs, msr);
 244}
 245
 246void giveup_altivec(struct task_struct *tsk)
 247{
 248	check_if_tm_restore_required(tsk);
 249
 250	msr_check_and_set(MSR_VEC);
 251	__giveup_altivec(tsk);
 252	msr_check_and_clear(MSR_VEC);
 253}
 254EXPORT_SYMBOL(giveup_altivec);
 255
 256void enable_kernel_altivec(void)
 257{
 258	unsigned long cpumsr;
 259
 260	WARN_ON(preemptible());
 261
 262	cpumsr = msr_check_and_set(MSR_VEC);
 263
 264	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) {
 265		check_if_tm_restore_required(current);
 266		/*
 267		 * If a thread has already been reclaimed then the
 268		 * checkpointed registers are on the CPU but have definitely
 269		 * been saved by the reclaim code. Don't need to and *cannot*
 270		 * giveup as this would save  to the 'live' structure not the
 271		 * checkpointed structure.
 272		 */
 273		if (!MSR_TM_ACTIVE(cpumsr) &&
 274		     MSR_TM_ACTIVE(current->thread.regs->msr))
 275			return;
 276		__giveup_altivec(current);
 277	}
 278}
 279EXPORT_SYMBOL(enable_kernel_altivec);
 280
 281/*
 282 * Make sure the VMX/Altivec register state in the
 283 * the thread_struct is up to date for task tsk.
 284 */
 285void flush_altivec_to_thread(struct task_struct *tsk)
 286{
 287	if (tsk->thread.regs) {
 288		preempt_disable();
 289		if (tsk->thread.regs->msr & MSR_VEC) {
 290			BUG_ON(tsk != current);
 291			giveup_altivec(tsk);
 292		}
 293		preempt_enable();
 294	}
 295}
 296EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 297#endif /* CONFIG_ALTIVEC */
 298
 299#ifdef CONFIG_VSX
 300static void __giveup_vsx(struct task_struct *tsk)
 301{
 302	unsigned long msr = tsk->thread.regs->msr;
 303
 304	/*
 305	 * We should never be setting MSR_VSX without also setting
 306	 * MSR_FP and MSR_VEC
 307	 */
 308	WARN_ON((msr & MSR_VSX) && !((msr & MSR_FP) && (msr & MSR_VEC)));
 309
 310	/* __giveup_fpu will clear MSR_VSX */
 311	if (msr & MSR_FP)
 312		__giveup_fpu(tsk);
 313	if (msr & MSR_VEC)
 314		__giveup_altivec(tsk);
 315}
 316
 317static void giveup_vsx(struct task_struct *tsk)
 318{
 319	check_if_tm_restore_required(tsk);
 320
 321	msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
 322	__giveup_vsx(tsk);
 323	msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);
 324}
 325
 326void enable_kernel_vsx(void)
 327{
 328	unsigned long cpumsr;
 329
 330	WARN_ON(preemptible());
 331
 332	cpumsr = msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
 333
 334	if (current->thread.regs &&
 335	    (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) {
 336		check_if_tm_restore_required(current);
 337		/*
 338		 * If a thread has already been reclaimed then the
 339		 * checkpointed registers are on the CPU but have definitely
 340		 * been saved by the reclaim code. Don't need to and *cannot*
 341		 * giveup as this would save  to the 'live' structure not the
 342		 * checkpointed structure.
 343		 */
 344		if (!MSR_TM_ACTIVE(cpumsr) &&
 345		     MSR_TM_ACTIVE(current->thread.regs->msr))
 346			return;
 347		__giveup_vsx(current);
 348	}
 349}
 350EXPORT_SYMBOL(enable_kernel_vsx);
 351
 352void flush_vsx_to_thread(struct task_struct *tsk)
 353{
 354	if (tsk->thread.regs) {
 355		preempt_disable();
 356		if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) {
 357			BUG_ON(tsk != current);
 358			giveup_vsx(tsk);
 359		}
 360		preempt_enable();
 361	}
 362}
 363EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
 364#endif /* CONFIG_VSX */
 365
 366#ifdef CONFIG_SPE
 367void giveup_spe(struct task_struct *tsk)
 368{
 369	check_if_tm_restore_required(tsk);
 370
 371	msr_check_and_set(MSR_SPE);
 372	__giveup_spe(tsk);
 373	msr_check_and_clear(MSR_SPE);
 374}
 375EXPORT_SYMBOL(giveup_spe);
 376
 377void enable_kernel_spe(void)
 378{
 379	WARN_ON(preemptible());
 380
 381	msr_check_and_set(MSR_SPE);
 382
 383	if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) {
 384		check_if_tm_restore_required(current);
 385		__giveup_spe(current);
 386	}
 387}
 388EXPORT_SYMBOL(enable_kernel_spe);
 389
 390void flush_spe_to_thread(struct task_struct *tsk)
 391{
 392	if (tsk->thread.regs) {
 393		preempt_disable();
 394		if (tsk->thread.regs->msr & MSR_SPE) {
 395			BUG_ON(tsk != current);
 396			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 397			giveup_spe(tsk);
 398		}
 399		preempt_enable();
 400	}
 401}
 402#endif /* CONFIG_SPE */
 403
 404static unsigned long msr_all_available;
 405
 406static int __init init_msr_all_available(void)
 407{
 408	if (IS_ENABLED(CONFIG_PPC_FPU))
 409		msr_all_available |= MSR_FP;
 410	if (cpu_has_feature(CPU_FTR_ALTIVEC))
 411		msr_all_available |= MSR_VEC;
 412	if (cpu_has_feature(CPU_FTR_VSX))
 413		msr_all_available |= MSR_VSX;
 414	if (cpu_has_feature(CPU_FTR_SPE))
 415		msr_all_available |= MSR_SPE;
 416
 417	return 0;
 418}
 419early_initcall(init_msr_all_available);
 420
 421void giveup_all(struct task_struct *tsk)
 422{
 423	unsigned long usermsr;
 424
 425	if (!tsk->thread.regs)
 426		return;
 427
 428	check_if_tm_restore_required(tsk);
 429
 430	usermsr = tsk->thread.regs->msr;
 431
 432	if ((usermsr & msr_all_available) == 0)
 433		return;
 434
 435	msr_check_and_set(msr_all_available);
 436
 437	WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC)));
 438
 439	if (usermsr & MSR_FP)
 440		__giveup_fpu(tsk);
 441	if (usermsr & MSR_VEC)
 442		__giveup_altivec(tsk);
 443	if (usermsr & MSR_SPE)
 444		__giveup_spe(tsk);
 445
 446	msr_check_and_clear(msr_all_available);
 447}
 448EXPORT_SYMBOL(giveup_all);
 449
 450#ifdef CONFIG_PPC_BOOK3S_64
 451#ifdef CONFIG_PPC_FPU
 452static bool should_restore_fp(void)
 453{
 454	if (current->thread.load_fp) {
 455		current->thread.load_fp++;
 456		return true;
 457	}
 458	return false;
 459}
 460
 461static void do_restore_fp(void)
 462{
 463	load_fp_state(&current->thread.fp_state);
 464}
 465#else
 466static bool should_restore_fp(void) { return false; }
 467static void do_restore_fp(void) { }
 468#endif /* CONFIG_PPC_FPU */
 469
 470#ifdef CONFIG_ALTIVEC
 471static bool should_restore_altivec(void)
 472{
 473	if (cpu_has_feature(CPU_FTR_ALTIVEC) && (current->thread.load_vec)) {
 474		current->thread.load_vec++;
 475		return true;
 476	}
 477	return false;
 478}
 479
 480static void do_restore_altivec(void)
 481{
 482	load_vr_state(&current->thread.vr_state);
 483	current->thread.used_vr = 1;
 484}
 485#else
 486static bool should_restore_altivec(void) { return false; }
 487static void do_restore_altivec(void) { }
 488#endif /* CONFIG_ALTIVEC */
 489
 490static bool should_restore_vsx(void)
 491{
 492	if (cpu_has_feature(CPU_FTR_VSX))
 493		return true;
 494	return false;
 495}
 496#ifdef CONFIG_VSX
 497static void do_restore_vsx(void)
 498{
 499	current->thread.used_vsr = 1;
 500}
 501#else
 502static void do_restore_vsx(void) { }
 503#endif /* CONFIG_VSX */
 504
 505/*
 506 * The exception exit path calls restore_math() with interrupts hard disabled
 507 * but the soft irq state not "reconciled". ftrace code that calls
 508 * local_irq_save/restore causes warnings.
 509 *
 510 * Rather than complicate the exit path, just don't trace restore_math. This
 511 * could be done by having ftrace entry code check for this un-reconciled
 512 * condition where MSR[EE]=0 and PACA_IRQ_HARD_DIS is not set, and
 513 * temporarily fix it up for the duration of the ftrace call.
 514 */
 515void notrace restore_math(struct pt_regs *regs)
 516{
 517	unsigned long msr;
 518	unsigned long new_msr = 0;
 519
 520	msr = regs->msr;
 521
 522	/*
 523	 * new_msr tracks the facilities that are to be restored. Only reload
 524	 * if the bit is not set in the user MSR (if it is set, the registers
 525	 * are live for the user thread).
 526	 */
 527	if ((!(msr & MSR_FP)) && should_restore_fp())
 528		new_msr |= MSR_FP;
 529
 530	if ((!(msr & MSR_VEC)) && should_restore_altivec())
 531		new_msr |= MSR_VEC;
 532
 533	if ((!(msr & MSR_VSX)) && should_restore_vsx()) {
 534		if (((msr | new_msr) & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC))
 535			new_msr |= MSR_VSX;
 536	}
 537
 538	if (new_msr) {
 539		unsigned long fpexc_mode = 0;
 540
 541		msr_check_and_set(new_msr);
 542
 543		if (new_msr & MSR_FP) {
 544			do_restore_fp();
 545
 546			// This also covers VSX, because VSX implies FP
 547			fpexc_mode = current->thread.fpexc_mode;
 548		}
 549
 550		if (new_msr & MSR_VEC)
 551			do_restore_altivec();
 552
 553		if (new_msr & MSR_VSX)
 554			do_restore_vsx();
 555
 556		msr_check_and_clear(new_msr);
 557
 558		regs_set_return_msr(regs, regs->msr | new_msr | fpexc_mode);
 559	}
 560}
 561#endif /* CONFIG_PPC_BOOK3S_64 */
 562
 563static void save_all(struct task_struct *tsk)
 564{
 565	unsigned long usermsr;
 566
 567	if (!tsk->thread.regs)
 568		return;
 569
 570	usermsr = tsk->thread.regs->msr;
 571
 572	if ((usermsr & msr_all_available) == 0)
 573		return;
 574
 575	msr_check_and_set(msr_all_available);
 576
 577	WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC)));
 578
 579	if (usermsr & MSR_FP)
 580		save_fpu(tsk);
 581
 582	if (usermsr & MSR_VEC)
 583		save_altivec(tsk);
 584
 585	if (usermsr & MSR_SPE)
 586		__giveup_spe(tsk);
 587
 588	msr_check_and_clear(msr_all_available);
 589}
 590
 591void flush_all_to_thread(struct task_struct *tsk)
 592{
 593	if (tsk->thread.regs) {
 594		preempt_disable();
 595		BUG_ON(tsk != current);
 596#ifdef CONFIG_SPE
 597		if (tsk->thread.regs->msr & MSR_SPE)
 598			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 599#endif
 600		save_all(tsk);
 601
 602		preempt_enable();
 603	}
 604}
 605EXPORT_SYMBOL(flush_all_to_thread);
 606
 607#ifdef CONFIG_PPC_ADV_DEBUG_REGS
 608void do_send_trap(struct pt_regs *regs, unsigned long address,
 609		  unsigned long error_code, int breakpt)
 610{
 611	current->thread.trap_nr = TRAP_HWBKPT;
 612	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 613			11, SIGSEGV) == NOTIFY_STOP)
 614		return;
 615
 616	/* Deliver the signal to userspace */
 617	force_sig_ptrace_errno_trap(breakpt, /* breakpoint or watchpoint id */
 618				    (void __user *)address);
 619}
 620#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
 621
 622static void do_break_handler(struct pt_regs *regs)
 623{
 624	struct arch_hw_breakpoint null_brk = {0};
 625	struct arch_hw_breakpoint *info;
 626	ppc_inst_t instr = ppc_inst(0);
 627	int type = 0;
 628	int size = 0;
 629	unsigned long ea;
 630	int i;
 631
 632	/*
 633	 * If underneath hw supports only one watchpoint, we know it
 634	 * caused exception. 8xx also falls into this category.
 635	 */
 636	if (nr_wp_slots() == 1) {
 637		__set_breakpoint(0, &null_brk);
 638		current->thread.hw_brk[0] = null_brk;
 639		current->thread.hw_brk[0].flags |= HW_BRK_FLAG_DISABLED;
 640		return;
 641	}
 642
 643	/* Otherwise find out which DAWR caused exception and disable it. */
 644	wp_get_instr_detail(regs, &instr, &type, &size, &ea);
 645
 646	for (i = 0; i < nr_wp_slots(); i++) {
 647		info = &current->thread.hw_brk[i];
 648		if (!info->address)
 649			continue;
 650
 651		if (wp_check_constraints(regs, instr, ea, type, size, info)) {
 652			__set_breakpoint(i, &null_brk);
 653			current->thread.hw_brk[i] = null_brk;
 654			current->thread.hw_brk[i].flags |= HW_BRK_FLAG_DISABLED;
 655		}
 656	}
 657}
 658
 659DEFINE_INTERRUPT_HANDLER(do_break)
 660{
 661	current->thread.trap_nr = TRAP_HWBKPT;
 662	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, regs->dsisr,
 663			11, SIGSEGV) == NOTIFY_STOP)
 664		return;
 665
 666	if (debugger_break_match(regs))
 667		return;
 668
 669	/*
 670	 * We reach here only when watchpoint exception is generated by ptrace
 671	 * event (or hw is buggy!). Now if CONFIG_HAVE_HW_BREAKPOINT is set,
 672	 * watchpoint is already handled by hw_breakpoint_handler() so we don't
 673	 * have to do anything. But when CONFIG_HAVE_HW_BREAKPOINT is not set,
 674	 * we need to manually handle the watchpoint here.
 675	 */
 676	if (!IS_ENABLED(CONFIG_HAVE_HW_BREAKPOINT))
 677		do_break_handler(regs);
 678
 679	/* Deliver the signal to userspace */
 680	force_sig_fault(SIGTRAP, TRAP_HWBKPT, (void __user *)regs->dar);
 681}
 682#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
 683
 684static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk[HBP_NUM_MAX]);
 685
 686#ifdef CONFIG_PPC_ADV_DEBUG_REGS
 687/*
 688 * Set the debug registers back to their default "safe" values.
 689 */
 690static void set_debug_reg_defaults(struct thread_struct *thread)
 691{
 692	thread->debug.iac1 = thread->debug.iac2 = 0;
 693#if CONFIG_PPC_ADV_DEBUG_IACS > 2
 694	thread->debug.iac3 = thread->debug.iac4 = 0;
 695#endif
 696	thread->debug.dac1 = thread->debug.dac2 = 0;
 697#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 698	thread->debug.dvc1 = thread->debug.dvc2 = 0;
 699#endif
 700	thread->debug.dbcr0 = 0;
 701#ifdef CONFIG_BOOKE
 702	/*
 703	 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 704	 */
 705	thread->debug.dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
 706			DBCR1_IAC3US | DBCR1_IAC4US;
 707	/*
 708	 * Force Data Address Compare User/Supervisor bits to be User-only
 709	 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 710	 */
 711	thread->debug.dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 712#else
 713	thread->debug.dbcr1 = 0;
 714#endif
 715}
 716
 717static void prime_debug_regs(struct debug_reg *debug)
 718{
 719	/*
 720	 * We could have inherited MSR_DE from userspace, since
 721	 * it doesn't get cleared on exception entry.  Make sure
 722	 * MSR_DE is clear before we enable any debug events.
 723	 */
 724	mtmsr(mfmsr() & ~MSR_DE);
 725
 726	mtspr(SPRN_IAC1, debug->iac1);
 727	mtspr(SPRN_IAC2, debug->iac2);
 728#if CONFIG_PPC_ADV_DEBUG_IACS > 2
 729	mtspr(SPRN_IAC3, debug->iac3);
 730	mtspr(SPRN_IAC4, debug->iac4);
 731#endif
 732	mtspr(SPRN_DAC1, debug->dac1);
 733	mtspr(SPRN_DAC2, debug->dac2);
 734#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 735	mtspr(SPRN_DVC1, debug->dvc1);
 736	mtspr(SPRN_DVC2, debug->dvc2);
 737#endif
 738	mtspr(SPRN_DBCR0, debug->dbcr0);
 739	mtspr(SPRN_DBCR1, debug->dbcr1);
 740#ifdef CONFIG_BOOKE
 741	mtspr(SPRN_DBCR2, debug->dbcr2);
 742#endif
 743}
 744/*
 745 * Unless neither the old or new thread are making use of the
 746 * debug registers, set the debug registers from the values
 747 * stored in the new thread.
 748 */
 749void switch_booke_debug_regs(struct debug_reg *new_debug)
 750{
 751	if ((current->thread.debug.dbcr0 & DBCR0_IDM)
 752		|| (new_debug->dbcr0 & DBCR0_IDM))
 753			prime_debug_regs(new_debug);
 754}
 755EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
 756#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
 757#ifndef CONFIG_HAVE_HW_BREAKPOINT
 758static void set_breakpoint(int i, struct arch_hw_breakpoint *brk)
 759{
 760	preempt_disable();
 761	__set_breakpoint(i, brk);
 762	preempt_enable();
 763}
 764
 765static void set_debug_reg_defaults(struct thread_struct *thread)
 766{
 767	int i;
 768	struct arch_hw_breakpoint null_brk = {0};
 769
 770	for (i = 0; i < nr_wp_slots(); i++) {
 771		thread->hw_brk[i] = null_brk;
 772		if (ppc_breakpoint_available())
 773			set_breakpoint(i, &thread->hw_brk[i]);
 774	}
 775}
 776
 777static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
 778				struct arch_hw_breakpoint *b)
 779{
 780	if (a->address != b->address)
 781		return false;
 782	if (a->type != b->type)
 783		return false;
 784	if (a->len != b->len)
 785		return false;
 786	/* no need to check hw_len. it's calculated from address and len */
 787	return true;
 788}
 789
 790static void switch_hw_breakpoint(struct task_struct *new)
 791{
 792	int i;
 793
 794	for (i = 0; i < nr_wp_slots(); i++) {
 795		if (likely(hw_brk_match(this_cpu_ptr(&current_brk[i]),
 796					&new->thread.hw_brk[i])))
 797			continue;
 798
 799		__set_breakpoint(i, &new->thread.hw_brk[i]);
 800	}
 801}
 802#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 803#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
 804
 805static inline int set_dabr(struct arch_hw_breakpoint *brk)
 806{
 807	unsigned long dabr, dabrx;
 808
 809	dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR);
 810	dabrx = ((brk->type >> 3) & 0x7);
 811
 812	if (ppc_md.set_dabr)
 813		return ppc_md.set_dabr(dabr, dabrx);
 814
 815	if (IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {
 816		mtspr(SPRN_DAC1, dabr);
 817		if (IS_ENABLED(CONFIG_PPC_47x))
 818			isync();
 819		return 0;
 820	} else if (IS_ENABLED(CONFIG_PPC_BOOK3S)) {
 821		mtspr(SPRN_DABR, dabr);
 822		if (cpu_has_feature(CPU_FTR_DABRX))
 823			mtspr(SPRN_DABRX, dabrx);
 824		return 0;
 825	} else {
 826		return -EINVAL;
 827	}
 828}
 829
 830static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
 831{
 832	unsigned long lctrl1 = LCTRL1_CTE_GT | LCTRL1_CTF_LT | LCTRL1_CRWE_RW |
 833			       LCTRL1_CRWF_RW;
 834	unsigned long lctrl2 = LCTRL2_LW0EN | LCTRL2_LW0LADC | LCTRL2_SLW0EN;
 835	unsigned long start_addr = ALIGN_DOWN(brk->address, HW_BREAKPOINT_SIZE);
 836	unsigned long end_addr = ALIGN(brk->address + brk->len, HW_BREAKPOINT_SIZE);
 837
 838	if (start_addr == 0)
 839		lctrl2 |= LCTRL2_LW0LA_F;
 840	else if (end_addr == 0)
 841		lctrl2 |= LCTRL2_LW0LA_E;
 842	else
 843		lctrl2 |= LCTRL2_LW0LA_EandF;
 844
 845	mtspr(SPRN_LCTRL2, 0);
 846
 847	if ((brk->type & HW_BRK_TYPE_RDWR) == 0)
 848		return 0;
 849
 850	if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_READ)
 851		lctrl1 |= LCTRL1_CRWE_RO | LCTRL1_CRWF_RO;
 852	if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_WRITE)
 853		lctrl1 |= LCTRL1_CRWE_WO | LCTRL1_CRWF_WO;
 854
 855	mtspr(SPRN_CMPE, start_addr - 1);
 856	mtspr(SPRN_CMPF, end_addr);
 857	mtspr(SPRN_LCTRL1, lctrl1);
 858	mtspr(SPRN_LCTRL2, lctrl2);
 859
 860	return 0;
 861}
 862
 863static void set_hw_breakpoint(int nr, struct arch_hw_breakpoint *brk)
 864{
 865	if (dawr_enabled())
 866		// Power8 or later
 867		set_dawr(nr, brk);
 868	else if (IS_ENABLED(CONFIG_PPC_8xx))
 869		set_breakpoint_8xx(brk);
 870	else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
 871		// Power7 or earlier
 872		set_dabr(brk);
 873	else
 874		// Shouldn't happen due to higher level checks
 875		WARN_ON_ONCE(1);
 876}
 877
 878void __set_breakpoint(int nr, struct arch_hw_breakpoint *brk)
 879{
 880	memcpy(this_cpu_ptr(&current_brk[nr]), brk, sizeof(*brk));
 881	set_hw_breakpoint(nr, brk);
 882}
 883
 884/* Check if we have DAWR or DABR hardware */
 885bool ppc_breakpoint_available(void)
 886{
 887	if (dawr_enabled())
 888		return true; /* POWER8 DAWR or POWER9 forced DAWR */
 889	if (cpu_has_feature(CPU_FTR_ARCH_207S))
 890		return false; /* POWER9 with DAWR disabled */
 891	/* DABR: Everything but POWER8 and POWER9 */
 892	return true;
 893}
 894EXPORT_SYMBOL_GPL(ppc_breakpoint_available);
 895
 896/* Disable the breakpoint in hardware without touching current_brk[] */
 897void suspend_breakpoints(void)
 898{
 899	struct arch_hw_breakpoint brk = {0};
 900	int i;
 901
 902	if (!ppc_breakpoint_available())
 903		return;
 904
 905	for (i = 0; i < nr_wp_slots(); i++)
 906		set_hw_breakpoint(i, &brk);
 907}
 908
 909/*
 910 * Re-enable breakpoints suspended by suspend_breakpoints() in hardware
 911 * from current_brk[]
 912 */
 913void restore_breakpoints(void)
 914{
 915	int i;
 916
 917	if (!ppc_breakpoint_available())
 918		return;
 919
 920	for (i = 0; i < nr_wp_slots(); i++)
 921		set_hw_breakpoint(i, this_cpu_ptr(&current_brk[i]));
 922}
 923
 924#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 925
 926static inline bool tm_enabled(struct task_struct *tsk)
 927{
 928	return tsk && tsk->thread.regs && (tsk->thread.regs->msr & MSR_TM);
 929}
 930
 931static void tm_reclaim_thread(struct thread_struct *thr, uint8_t cause)
 932{
 933	/*
 934	 * Use the current MSR TM suspended bit to track if we have
 935	 * checkpointed state outstanding.
 936	 * On signal delivery, we'd normally reclaim the checkpointed
 937	 * state to obtain stack pointer (see:get_tm_stackpointer()).
 938	 * This will then directly return to userspace without going
 939	 * through __switch_to(). However, if the stack frame is bad,
 940	 * we need to exit this thread which calls __switch_to() which
 941	 * will again attempt to reclaim the already saved tm state.
 942	 * Hence we need to check that we've not already reclaimed
 943	 * this state.
 944	 * We do this using the current MSR, rather tracking it in
 945	 * some specific thread_struct bit, as it has the additional
 946	 * benefit of checking for a potential TM bad thing exception.
 947	 */
 948	if (!MSR_TM_SUSPENDED(mfmsr()))
 949		return;
 950
 951	giveup_all(container_of(thr, struct task_struct, thread));
 952
 953	tm_reclaim(thr, cause);
 954
 955	/*
 956	 * If we are in a transaction and FP is off then we can't have
 957	 * used FP inside that transaction. Hence the checkpointed
 958	 * state is the same as the live state. We need to copy the
 959	 * live state to the checkpointed state so that when the
 960	 * transaction is restored, the checkpointed state is correct
 961	 * and the aborted transaction sees the correct state. We use
 962	 * ckpt_regs.msr here as that's what tm_reclaim will use to
 963	 * determine if it's going to write the checkpointed state or
 964	 * not. So either this will write the checkpointed registers,
 965	 * or reclaim will. Similarly for VMX.
 966	 */
 967	if ((thr->ckpt_regs.msr & MSR_FP) == 0)
 968		memcpy(&thr->ckfp_state, &thr->fp_state,
 969		       sizeof(struct thread_fp_state));
 970	if ((thr->ckpt_regs.msr & MSR_VEC) == 0)
 971		memcpy(&thr->ckvr_state, &thr->vr_state,
 972		       sizeof(struct thread_vr_state));
 973}
 974
 975void tm_reclaim_current(uint8_t cause)
 976{
 977	tm_enable();
 978	tm_reclaim_thread(&current->thread, cause);
 979}
 980
 981static inline void tm_reclaim_task(struct task_struct *tsk)
 982{
 983	/* We have to work out if we're switching from/to a task that's in the
 984	 * middle of a transaction.
 985	 *
 986	 * In switching we need to maintain a 2nd register state as
 987	 * oldtask->thread.ckpt_regs.  We tm_reclaim(oldproc); this saves the
 988	 * checkpointed (tbegin) state in ckpt_regs, ckfp_state and
 989	 * ckvr_state
 990	 *
 991	 * We also context switch (save) TFHAR/TEXASR/TFIAR in here.
 992	 */
 993	struct thread_struct *thr = &tsk->thread;
 994
 995	if (!thr->regs)
 996		return;
 997
 998	if (!MSR_TM_ACTIVE(thr->regs->msr))
 999		goto out_and_saveregs;
1000
1001	WARN_ON(tm_suspend_disabled);
1002
1003	TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
1004		 "ccr=%lx, msr=%lx, trap=%lx)\n",
1005		 tsk->pid, thr->regs->nip,
1006		 thr->regs->ccr, thr->regs->msr,
1007		 thr->regs->trap);
1008
1009	tm_reclaim_thread(thr, TM_CAUSE_RESCHED);
1010
1011	TM_DEBUG("--- tm_reclaim on pid %d complete\n",
1012		 tsk->pid);
1013
1014out_and_saveregs:
1015	/* Always save the regs here, even if a transaction's not active.
1016	 * This context-switches a thread's TM info SPRs.  We do it here to
1017	 * be consistent with the restore path (in recheckpoint) which
1018	 * cannot happen later in _switch().
1019	 */
1020	tm_save_sprs(thr);
1021}
1022
1023extern void __tm_recheckpoint(struct thread_struct *thread);
1024
1025void tm_recheckpoint(struct thread_struct *thread)
1026{
1027	unsigned long flags;
1028
1029	if (!(thread->regs->msr & MSR_TM))
1030		return;
1031
1032	/* We really can't be interrupted here as the TEXASR registers can't
1033	 * change and later in the trecheckpoint code, we have a userspace R1.
1034	 * So let's hard disable over this region.
1035	 */
1036	local_irq_save(flags);
1037	hard_irq_disable();
1038
1039	/* The TM SPRs are restored here, so that TEXASR.FS can be set
1040	 * before the trecheckpoint and no explosion occurs.
1041	 */
1042	tm_restore_sprs(thread);
1043
1044	__tm_recheckpoint(thread);
1045
1046	local_irq_restore(flags);
1047}
1048
1049static inline void tm_recheckpoint_new_task(struct task_struct *new)
1050{
1051	if (!cpu_has_feature(CPU_FTR_TM))
1052		return;
1053
1054	/* Recheckpoint the registers of the thread we're about to switch to.
1055	 *
1056	 * If the task was using FP, we non-lazily reload both the original and
1057	 * the speculative FP register states.  This is because the kernel
1058	 * doesn't see if/when a TM rollback occurs, so if we take an FP
1059	 * unavailable later, we are unable to determine which set of FP regs
1060	 * need to be restored.
1061	 */
1062	if (!tm_enabled(new))
1063		return;
1064
1065	if (!MSR_TM_ACTIVE(new->thread.regs->msr)){
1066		tm_restore_sprs(&new->thread);
1067		return;
1068	}
1069	/* Recheckpoint to restore original checkpointed register state. */
1070	TM_DEBUG("*** tm_recheckpoint of pid %d (new->msr 0x%lx)\n",
1071		 new->pid, new->thread.regs->msr);
1072
1073	tm_recheckpoint(&new->thread);
1074
1075	/*
1076	 * The checkpointed state has been restored but the live state has
1077	 * not, ensure all the math functionality is turned off to trigger
1078	 * restore_math() to reload.
1079	 */
1080	new->thread.regs->msr &= ~(MSR_FP | MSR_VEC | MSR_VSX);
1081
1082	TM_DEBUG("*** tm_recheckpoint of pid %d complete "
1083		 "(kernel msr 0x%lx)\n",
1084		 new->pid, mfmsr());
1085}
1086
1087static inline void __switch_to_tm(struct task_struct *prev,
1088		struct task_struct *new)
1089{
1090	if (cpu_has_feature(CPU_FTR_TM)) {
1091		if (tm_enabled(prev) || tm_enabled(new))
1092			tm_enable();
1093
1094		if (tm_enabled(prev)) {
1095			prev->thread.load_tm++;
1096			tm_reclaim_task(prev);
1097			if (!MSR_TM_ACTIVE(prev->thread.regs->msr) && prev->thread.load_tm == 0)
1098				prev->thread.regs->msr &= ~MSR_TM;
1099		}
1100
1101		tm_recheckpoint_new_task(new);
1102	}
1103}
1104
1105/*
1106 * This is called if we are on the way out to userspace and the
1107 * TIF_RESTORE_TM flag is set.  It checks if we need to reload
1108 * FP and/or vector state and does so if necessary.
1109 * If userspace is inside a transaction (whether active or
1110 * suspended) and FP/VMX/VSX instructions have ever been enabled
1111 * inside that transaction, then we have to keep them enabled
1112 * and keep the FP/VMX/VSX state loaded while ever the transaction
1113 * continues.  The reason is that if we didn't, and subsequently
1114 * got a FP/VMX/VSX unavailable interrupt inside a transaction,
1115 * we don't know whether it's the same transaction, and thus we
1116 * don't know which of the checkpointed state and the transactional
1117 * state to use.
1118 */
1119void restore_tm_state(struct pt_regs *regs)
1120{
1121	unsigned long msr_diff;
1122
1123	/*
1124	 * This is the only moment we should clear TIF_RESTORE_TM as
1125	 * it is here that ckpt_regs.msr and pt_regs.msr become the same
1126	 * again, anything else could lead to an incorrect ckpt_msr being
1127	 * saved and therefore incorrect signal contexts.
1128	 */
1129	clear_thread_flag(TIF_RESTORE_TM);
1130	if (!MSR_TM_ACTIVE(regs->msr))
1131		return;
1132
1133	msr_diff = current->thread.ckpt_regs.msr & ~regs->msr;
1134	msr_diff &= MSR_FP | MSR_VEC | MSR_VSX;
1135
1136	/* Ensure that restore_math() will restore */
1137	if (msr_diff & MSR_FP)
1138		current->thread.load_fp = 1;
1139#ifdef CONFIG_ALTIVEC
1140	if (cpu_has_feature(CPU_FTR_ALTIVEC) && msr_diff & MSR_VEC)
1141		current->thread.load_vec = 1;
1142#endif
1143	restore_math(regs);
1144
1145	regs_set_return_msr(regs, regs->msr | msr_diff);
1146}
1147
1148#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
1149#define tm_recheckpoint_new_task(new)
1150#define __switch_to_tm(prev, new)
1151void tm_reclaim_current(uint8_t cause) {}
1152#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1153
1154static inline void save_sprs(struct thread_struct *t)
1155{
1156#ifdef CONFIG_ALTIVEC
1157	if (cpu_has_feature(CPU_FTR_ALTIVEC))
1158		t->vrsave = mfspr(SPRN_VRSAVE);
1159#endif
1160#ifdef CONFIG_SPE
1161	if (cpu_has_feature(CPU_FTR_SPE))
1162		t->spefscr = mfspr(SPRN_SPEFSCR);
1163#endif
1164#ifdef CONFIG_PPC_BOOK3S_64
1165	if (cpu_has_feature(CPU_FTR_DSCR))
1166		t->dscr = mfspr(SPRN_DSCR);
1167
1168	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
1169		t->bescr = mfspr(SPRN_BESCR);
1170		t->ebbhr = mfspr(SPRN_EBBHR);
1171		t->ebbrr = mfspr(SPRN_EBBRR);
1172
1173		t->fscr = mfspr(SPRN_FSCR);
1174
1175		/*
1176		 * Note that the TAR is not available for use in the kernel.
1177		 * (To provide this, the TAR should be backed up/restored on
1178		 * exception entry/exit instead, and be in pt_regs.  FIXME,
1179		 * this should be in pt_regs anyway (for debug).)
1180		 */
1181		t->tar = mfspr(SPRN_TAR);
1182	}
1183
1184	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
1185		t->hashkeyr = mfspr(SPRN_HASHKEYR);
1186
1187	if (cpu_has_feature(CPU_FTR_ARCH_31))
1188		t->dexcr = mfspr(SPRN_DEXCR);
1189#endif
1190}
1191
1192#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
1193void kvmppc_save_user_regs(void)
1194{
1195	unsigned long usermsr;
1196
1197	if (!current->thread.regs)
1198		return;
1199
1200	usermsr = current->thread.regs->msr;
1201
1202	/* Caller has enabled FP/VEC/VSX/TM in MSR */
1203	if (usermsr & MSR_FP)
1204		__giveup_fpu(current);
1205	if (usermsr & MSR_VEC)
1206		__giveup_altivec(current);
1207
1208#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1209	if (usermsr & MSR_TM) {
1210		current->thread.tm_tfhar = mfspr(SPRN_TFHAR);
1211		current->thread.tm_tfiar = mfspr(SPRN_TFIAR);
1212		current->thread.tm_texasr = mfspr(SPRN_TEXASR);
1213		current->thread.regs->msr &= ~MSR_TM;
1214	}
1215#endif
1216}
1217EXPORT_SYMBOL_GPL(kvmppc_save_user_regs);
1218
1219void kvmppc_save_current_sprs(void)
1220{
1221	save_sprs(&current->thread);
1222}
1223EXPORT_SYMBOL_GPL(kvmppc_save_current_sprs);
1224#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
1225
1226static inline void restore_sprs(struct thread_struct *old_thread,
1227				struct thread_struct *new_thread)
1228{
1229#ifdef CONFIG_ALTIVEC
1230	if (cpu_has_feature(CPU_FTR_ALTIVEC) &&
1231	    old_thread->vrsave != new_thread->vrsave)
1232		mtspr(SPRN_VRSAVE, new_thread->vrsave);
1233#endif
1234#ifdef CONFIG_SPE
1235	if (cpu_has_feature(CPU_FTR_SPE) &&
1236	    old_thread->spefscr != new_thread->spefscr)
1237		mtspr(SPRN_SPEFSCR, new_thread->spefscr);
1238#endif
1239#ifdef CONFIG_PPC_BOOK3S_64
1240	if (cpu_has_feature(CPU_FTR_DSCR)) {
1241		u64 dscr = get_paca()->dscr_default;
1242		if (new_thread->dscr_inherit)
1243			dscr = new_thread->dscr;
1244
1245		if (old_thread->dscr != dscr)
1246			mtspr(SPRN_DSCR, dscr);
1247	}
1248
1249	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
1250		if (old_thread->bescr != new_thread->bescr)
1251			mtspr(SPRN_BESCR, new_thread->bescr);
1252		if (old_thread->ebbhr != new_thread->ebbhr)
1253			mtspr(SPRN_EBBHR, new_thread->ebbhr);
1254		if (old_thread->ebbrr != new_thread->ebbrr)
1255			mtspr(SPRN_EBBRR, new_thread->ebbrr);
1256
1257		if (old_thread->fscr != new_thread->fscr)
1258			mtspr(SPRN_FSCR, new_thread->fscr);
1259
1260		if (old_thread->tar != new_thread->tar)
1261			mtspr(SPRN_TAR, new_thread->tar);
1262	}
1263
1264	if (cpu_has_feature(CPU_FTR_P9_TIDR) &&
1265	    old_thread->tidr != new_thread->tidr)
1266		mtspr(SPRN_TIDR, new_thread->tidr);
1267
1268	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) &&
1269	    old_thread->hashkeyr != new_thread->hashkeyr)
1270		mtspr(SPRN_HASHKEYR, new_thread->hashkeyr);
1271
1272	if (cpu_has_feature(CPU_FTR_ARCH_31) &&
1273	    old_thread->dexcr != new_thread->dexcr)
1274		mtspr(SPRN_DEXCR, new_thread->dexcr);
1275#endif
1276
1277}
1278
1279struct task_struct *__switch_to(struct task_struct *prev,
1280	struct task_struct *new)
1281{
1282	struct thread_struct *new_thread, *old_thread;
1283	struct task_struct *last;
1284#ifdef CONFIG_PPC_64S_HASH_MMU
1285	struct ppc64_tlb_batch *batch;
1286#endif
1287
1288	new_thread = &new->thread;
1289	old_thread = &current->thread;
1290
1291	WARN_ON(!irqs_disabled());
1292
1293#ifdef CONFIG_PPC_64S_HASH_MMU
1294	batch = this_cpu_ptr(&ppc64_tlb_batch);
1295	if (batch->active) {
1296		current_thread_info()->local_flags |= _TLF_LAZY_MMU;
1297		if (batch->index)
1298			__flush_tlb_pending(batch);
1299		batch->active = 0;
1300	}
1301
1302	/*
1303	 * On POWER9 the copy-paste buffer can only paste into
1304	 * foreign real addresses, so unprivileged processes can not
1305	 * see the data or use it in any way unless they have
1306	 * foreign real mappings. If the new process has the foreign
1307	 * real address mappings, we must issue a cp_abort to clear
1308	 * any state and prevent snooping, corruption or a covert
1309	 * channel. ISA v3.1 supports paste into local memory.
1310	 */
1311	if (new->mm && (cpu_has_feature(CPU_FTR_ARCH_31) ||
1312			atomic_read(&new->mm->context.vas_windows)))
1313		asm volatile(PPC_CP_ABORT);
1314#endif /* CONFIG_PPC_BOOK3S_64 */
1315
1316#ifdef CONFIG_PPC_ADV_DEBUG_REGS
1317	switch_booke_debug_regs(&new->thread.debug);
1318#else
1319/*
1320 * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
1321 * schedule DABR
1322 */
1323#ifndef CONFIG_HAVE_HW_BREAKPOINT
1324	switch_hw_breakpoint(new);
1325#endif /* CONFIG_HAVE_HW_BREAKPOINT */
1326#endif
1327
1328	/*
1329	 * We need to save SPRs before treclaim/trecheckpoint as these will
1330	 * change a number of them.
1331	 */
1332	save_sprs(&prev->thread);
1333
1334	/* Save FPU, Altivec, VSX and SPE state */
1335	giveup_all(prev);
1336
1337	__switch_to_tm(prev, new);
1338
1339	if (!radix_enabled()) {
1340		/*
1341		 * We can't take a PMU exception inside _switch() since there
1342		 * is a window where the kernel stack SLB and the kernel stack
1343		 * are out of sync. Hard disable here.
1344		 */
1345		hard_irq_disable();
1346	}
1347
1348	/*
1349	 * Call restore_sprs() and set_return_regs_changed() before calling
1350	 * _switch(). If we move it after _switch() then we miss out on calling
1351	 * it for new tasks. The reason for this is we manually create a stack
1352	 * frame for new tasks that directly returns through ret_from_fork() or
1353	 * ret_from_kernel_thread(). See copy_thread() for details.
1354	 */
1355	restore_sprs(old_thread, new_thread);
1356
1357	set_return_regs_changed(); /* _switch changes stack (and regs) */
1358
1359	if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
1360		kuap_assert_locked();
1361
1362	last = _switch(old_thread, new_thread);
1363
1364	/*
1365	 * Nothing after _switch will be run for newly created tasks,
1366	 * because they switch directly to ret_from_fork/ret_from_kernel_thread
1367	 * etc. Code added here should have a comment explaining why that is
1368	 * okay.
1369	 */
1370
1371#ifdef CONFIG_PPC_BOOK3S_64
1372#ifdef CONFIG_PPC_64S_HASH_MMU
1373	/*
1374	 * This applies to a process that was context switched while inside
1375	 * arch_enter_lazy_mmu_mode(), to re-activate the batch that was
1376	 * deactivated above, before _switch(). This will never be the case
1377	 * for new tasks.
1378	 */
1379	if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
1380		current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
1381		batch = this_cpu_ptr(&ppc64_tlb_batch);
1382		batch->active = 1;
1383	}
1384#endif
1385
1386	/*
1387	 * Math facilities are masked out of the child MSR in copy_thread.
1388	 * A new task does not need to restore_math because it will
1389	 * demand fault them.
1390	 */
1391	if (current->thread.regs)
1392		restore_math(current->thread.regs);
1393#endif /* CONFIG_PPC_BOOK3S_64 */
1394
1395	return last;
1396}
1397
1398#define NR_INSN_TO_PRINT	16
1399
1400static void show_instructions(struct pt_regs *regs)
1401{
1402	int i;
1403	unsigned long nip = regs->nip;
1404	unsigned long pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
1405
1406	printk("Code: ");
1407
1408	/*
1409	 * If we were executing with the MMU off for instructions, adjust pc
1410	 * rather than printing XXXXXXXX.
1411	 */
1412	if (!IS_ENABLED(CONFIG_BOOKE) && !(regs->msr & MSR_IR)) {
1413		pc = (unsigned long)phys_to_virt(pc);
1414		nip = (unsigned long)phys_to_virt(regs->nip);
1415	}
1416
1417	for (i = 0; i < NR_INSN_TO_PRINT; i++) {
1418		int instr;
1419
1420		if (get_kernel_nofault(instr, (const void *)pc)) {
1421			pr_cont("XXXXXXXX ");
1422		} else {
1423			if (nip == pc)
1424				pr_cont("<%08x> ", instr);
1425			else
1426				pr_cont("%08x ", instr);
1427		}
1428
1429		pc += sizeof(int);
1430	}
1431
1432	pr_cont("\n");
1433}
1434
1435void show_user_instructions(struct pt_regs *regs)
1436{
1437	unsigned long pc;
1438	int n = NR_INSN_TO_PRINT;
1439	struct seq_buf s;
1440	char buf[96]; /* enough for 8 times 9 + 2 chars */
1441
1442	pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));
1443
1444	seq_buf_init(&s, buf, sizeof(buf));
1445
1446	while (n) {
1447		int i;
1448
1449		seq_buf_clear(&s);
1450
1451		for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) {
1452			int instr;
1453
1454			if (copy_from_user_nofault(&instr, (void __user *)pc,
1455					sizeof(instr))) {
1456				seq_buf_printf(&s, "XXXXXXXX ");
1457				continue;
1458			}
1459			seq_buf_printf(&s, regs->nip == pc ? "<%08x> " : "%08x ", instr);
1460		}
1461
1462		if (!seq_buf_has_overflowed(&s))
1463			pr_info("%s[%d]: code: %s\n", current->comm,
1464				current->pid, s.buffer);
1465	}
1466}
1467
1468struct regbit {
1469	unsigned long bit;
1470	const char *name;
1471};
1472
1473static struct regbit msr_bits[] = {
1474#if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
1475	{MSR_SF,	"SF"},
1476	{MSR_HV,	"HV"},
1477#endif
1478	{MSR_VEC,	"VEC"},
1479	{MSR_VSX,	"VSX"},
1480#ifdef CONFIG_BOOKE
1481	{MSR_CE,	"CE"},
1482#endif
1483	{MSR_EE,	"EE"},
1484	{MSR_PR,	"PR"},
1485	{MSR_FP,	"FP"},
1486	{MSR_ME,	"ME"},
1487#ifdef CONFIG_BOOKE
1488	{MSR_DE,	"DE"},
1489#else
1490	{MSR_SE,	"SE"},
1491	{MSR_BE,	"BE"},
1492#endif
1493	{MSR_IR,	"IR"},
1494	{MSR_DR,	"DR"},
1495	{MSR_PMM,	"PMM"},
1496#ifndef CONFIG_BOOKE
1497	{MSR_RI,	"RI"},
1498	{MSR_LE,	"LE"},
1499#endif
1500	{0,		NULL}
1501};
1502
1503static void print_bits(unsigned long val, struct regbit *bits, const char *sep)
1504{
1505	const char *s = "";
1506
1507	for (; bits->bit; ++bits)
1508		if (val & bits->bit) {
1509			pr_cont("%s%s", s, bits->name);
1510			s = sep;
1511		}
1512}
1513
1514#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1515static struct regbit msr_tm_bits[] = {
1516	{MSR_TS_T,	"T"},
1517	{MSR_TS_S,	"S"},
1518	{MSR_TM,	"E"},
1519	{0,		NULL}
1520};
1521
1522static void print_tm_bits(unsigned long val)
1523{
1524/*
1525 * This only prints something if at least one of the TM bit is set.
1526 * Inside the TM[], the output means:
1527 *   E: Enabled		(bit 32)
1528 *   S: Suspended	(bit 33)
1529 *   T: Transactional	(bit 34)
1530 */
1531	if (val & (MSR_TM | MSR_TS_S | MSR_TS_T)) {
1532		pr_cont(",TM[");
1533		print_bits(val, msr_tm_bits, "");
1534		pr_cont("]");
1535	}
1536}
1537#else
1538static void print_tm_bits(unsigned long val) {}
1539#endif
1540
1541static void print_msr_bits(unsigned long val)
1542{
1543	pr_cont("<");
1544	print_bits(val, msr_bits, ",");
1545	print_tm_bits(val);
1546	pr_cont(">");
1547}
1548
1549#ifdef CONFIG_PPC64
1550#define REG		"%016lx"
1551#define REGS_PER_LINE	4
1552#else
1553#define REG		"%08lx"
1554#define REGS_PER_LINE	8
1555#endif
1556
1557static void __show_regs(struct pt_regs *regs)
1558{
1559	int i, trap;
1560
1561	printk("NIP:  "REG" LR: "REG" CTR: "REG"\n",
1562	       regs->nip, regs->link, regs->ctr);
1563	printk("REGS: %px TRAP: %04lx   %s  (%s)\n",
1564	       regs, regs->trap, print_tainted(), init_utsname()->release);
1565	printk("MSR:  "REG" ", regs->msr);
1566	print_msr_bits(regs->msr);
1567	pr_cont("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
1568	trap = TRAP(regs);
1569	if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR))
1570		pr_cont("CFAR: "REG" ", regs->orig_gpr3);
1571	if (trap == INTERRUPT_MACHINE_CHECK ||
1572	    trap == INTERRUPT_DATA_STORAGE ||
1573	    trap == INTERRUPT_ALIGNMENT) {
1574		if (IS_ENABLED(CONFIG_BOOKE))
1575			pr_cont("DEAR: "REG" ESR: "REG" ", regs->dear, regs->esr);
1576		else
1577			pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
1578	}
1579
1580#ifdef CONFIG_PPC64
1581	pr_cont("IRQMASK: %lx ", regs->softe);
1582#endif
1583#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1584	if (MSR_TM_ACTIVE(regs->msr))
1585		pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
1586#endif
1587
1588	for (i = 0;  i < 32;  i++) {
1589		if ((i % REGS_PER_LINE) == 0)
1590			pr_cont("\nGPR%02d: ", i);
1591		pr_cont(REG " ", regs->gpr[i]);
1592	}
1593	pr_cont("\n");
1594	/*
1595	 * Lookup NIP late so we have the best change of getting the
1596	 * above info out without failing
1597	 */
1598	if (IS_ENABLED(CONFIG_KALLSYMS)) {
1599		printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1600		printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1601	}
1602}
1603
1604void show_regs(struct pt_regs *regs)
1605{
1606	show_regs_print_info(KERN_DEFAULT);
1607	__show_regs(regs);
1608	show_stack(current, (unsigned long *) regs->gpr[1], KERN_DEFAULT);
1609	if (!user_mode(regs))
1610		show_instructions(regs);
1611}
1612
1613void flush_thread(void)
1614{
1615#ifdef CONFIG_HAVE_HW_BREAKPOINT
1616	flush_ptrace_hw_breakpoint(current);
1617#else /* CONFIG_HAVE_HW_BREAKPOINT */
1618	set_debug_reg_defaults(&current->thread);
1619#endif /* CONFIG_HAVE_HW_BREAKPOINT */
1620}
1621
1622void arch_setup_new_exec(void)
1623{
1624
1625#ifdef CONFIG_PPC_BOOK3S_64
1626	if (!radix_enabled())
1627		hash__setup_new_exec();
1628#endif
1629	/*
1630	 * If we exec out of a kernel thread then thread.regs will not be
1631	 * set.  Do it now.
1632	 */
1633	if (!current->thread.regs) {
1634		struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
1635		current->thread.regs = regs - 1;
1636	}
1637
1638#ifdef CONFIG_PPC_MEM_KEYS
1639	current->thread.regs->amr  = default_amr;
1640	current->thread.regs->iamr  = default_iamr;
1641#endif
1642
1643#ifdef CONFIG_PPC_BOOK3S_64
1644	if (cpu_has_feature(CPU_FTR_ARCH_31)) {
1645		current->thread.dexcr = current->thread.dexcr_onexec;
1646		mtspr(SPRN_DEXCR, current->thread.dexcr);
1647	}
1648#endif /* CONFIG_PPC_BOOK3S_64 */
1649}
1650
1651#ifdef CONFIG_PPC64
1652/*
1653 * Assign a TIDR (thread ID) for task @t and set it in the thread
1654 * structure. For now, we only support setting TIDR for 'current' task.
1655 *
1656 * Since the TID value is a truncated form of it PID, it is possible
1657 * (but unlikely) for 2 threads to have the same TID. In the unlikely event
1658 * that 2 threads share the same TID and are waiting, one of the following
1659 * cases will happen:
1660 *
1661 * 1. The correct thread is running, the wrong thread is not
1662 * In this situation, the correct thread is woken and proceeds to pass its
1663 * condition check.
1664 *
1665 * 2. Neither threads are running
1666 * In this situation, neither thread will be woken. When scheduled, the waiting
1667 * threads will execute either a wait, which will return immediately, followed
1668 * by a condition check, which will pass for the correct thread and fail
1669 * for the wrong thread, or they will execute the condition check immediately.
1670 *
1671 * 3. The wrong thread is running, the correct thread is not
1672 * The wrong thread will be woken, but will fail its condition check and
1673 * re-execute wait. The correct thread, when scheduled, will execute either
1674 * its condition check (which will pass), or wait, which returns immediately
1675 * when called the first time after the thread is scheduled, followed by its
1676 * condition check (which will pass).
1677 *
1678 * 4. Both threads are running
1679 * Both threads will be woken. The wrong thread will fail its condition check
1680 * and execute another wait, while the correct thread will pass its condition
1681 * check.
1682 *
1683 * @t: the task to set the thread ID for
1684 */
1685int set_thread_tidr(struct task_struct *t)
1686{
1687	if (!cpu_has_feature(CPU_FTR_P9_TIDR))
1688		return -EINVAL;
1689
1690	if (t != current)
1691		return -EINVAL;
1692
1693	if (t->thread.tidr)
1694		return 0;
1695
1696	t->thread.tidr = (u16)task_pid_nr(t);
1697	mtspr(SPRN_TIDR, t->thread.tidr);
1698
1699	return 0;
1700}
1701EXPORT_SYMBOL_GPL(set_thread_tidr);
1702
1703#endif /* CONFIG_PPC64 */
1704
1705/*
1706 * this gets called so that we can store coprocessor state into memory and
1707 * copy the current task into the new thread.
1708 */
1709int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
1710{
1711	flush_all_to_thread(src);
1712	/*
1713	 * Flush TM state out so we can copy it.  __switch_to_tm() does this
1714	 * flush but it removes the checkpointed state from the current CPU and
1715	 * transitions the CPU out of TM mode.  Hence we need to call
1716	 * tm_recheckpoint_new_task() (on the same task) to restore the
1717	 * checkpointed state back and the TM mode.
1718	 *
1719	 * Can't pass dst because it isn't ready. Doesn't matter, passing
1720	 * dst is only important for __switch_to()
1721	 */
1722	__switch_to_tm(src, src);
1723
1724	*dst = *src;
1725
1726	clear_task_ebb(dst);
1727
1728	return 0;
1729}
1730
1731static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
1732{
1733#ifdef CONFIG_PPC_64S_HASH_MMU
1734	unsigned long sp_vsid;
1735	unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
1736
1737	if (radix_enabled())
1738		return;
1739
1740	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
1741		sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
1742			<< SLB_VSID_SHIFT_1T;
1743	else
1744		sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
1745			<< SLB_VSID_SHIFT;
1746	sp_vsid |= SLB_VSID_KERNEL | llp;
1747	p->thread.ksp_vsid = sp_vsid;
1748#endif
1749}
1750
1751/*
1752 * Copy a thread..
1753 */
1754
1755/*
1756 * Copy architecture-specific thread state
1757 */
1758int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
1759{
1760	struct pt_regs *kregs; /* Switch frame regs */
1761	extern void ret_from_fork(void);
1762	extern void ret_from_fork_scv(void);
1763	extern void ret_from_kernel_user_thread(void);
1764	extern void start_kernel_thread(void);
1765	void (*f)(void);
1766	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
1767#ifdef CONFIG_HAVE_HW_BREAKPOINT
1768	int i;
1769#endif
1770
1771	klp_init_thread_info(p);
1772
1773	if (unlikely(p->flags & PF_KTHREAD)) {
1774		/* kernel thread */
1775
1776		/* Create initial minimum stack frame. */
1777		sp -= STACK_FRAME_MIN_SIZE;
1778		((unsigned long *)sp)[0] = 0;
1779
1780		f = start_kernel_thread;
1781		p->thread.regs = NULL;	/* no user register state */
1782		clear_tsk_compat_task(p);
1783	} else {
1784		/* user thread */
1785		struct pt_regs *childregs;
1786
1787		/* Create initial user return stack frame. */
1788		sp -= STACK_USER_INT_FRAME_SIZE;
1789		*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
1790
1791		childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS);
1792
1793		if (unlikely(args->fn)) {
1794			/*
1795			 * A user space thread, but it first runs a kernel
1796			 * thread, and then returns as though it had called
1797			 * execve rather than fork, so user regs will be
1798			 * filled in (e.g., by kernel_execve()).
1799			 */
1800			((unsigned long *)sp)[0] = 0;
1801			memset(childregs, 0, sizeof(struct pt_regs));
1802#ifdef CONFIG_PPC64
1803			childregs->softe = IRQS_ENABLED;
1804#endif
1805			f = ret_from_kernel_user_thread;
1806		} else {
1807			struct pt_regs *regs = current_pt_regs();
1808			unsigned long clone_flags = args->flags;
1809			unsigned long usp = args->stack;
1810
1811			/* Copy registers */
1812			*childregs = *regs;
1813			if (usp)
1814				childregs->gpr[1] = usp;
1815			((unsigned long *)sp)[0] = childregs->gpr[1];
1816#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
1817			WARN_ON_ONCE(childregs->softe != IRQS_ENABLED);
1818#endif
1819			if (clone_flags & CLONE_SETTLS) {
1820				unsigned long tls = args->tls;
1821
1822				if (!is_32bit_task())
1823					childregs->gpr[13] = tls;
1824				else
1825					childregs->gpr[2] = tls;
1826			}
1827
1828			if (trap_is_scv(regs))
1829				f = ret_from_fork_scv;
1830			else
1831				f = ret_from_fork;
1832		}
1833
1834		childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
1835		p->thread.regs = childregs;
1836	}
1837
1838	/*
1839	 * The way this works is that at some point in the future
1840	 * some task will call _switch to switch to the new task.
1841	 * That will pop off the stack frame created below and start
1842	 * the new task running at ret_from_fork.  The new task will
1843	 * do some house keeping and then return from the fork or clone
1844	 * system call, using the stack frame created above.
1845	 */
1846	((unsigned long *)sp)[STACK_FRAME_LR_SAVE] = (unsigned long)f;
1847	sp -= STACK_SWITCH_FRAME_SIZE;
1848	((unsigned long *)sp)[0] = sp + STACK_SWITCH_FRAME_SIZE;
1849	kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);
1850	kregs->nip = ppc_function_entry(f);
1851	if (unlikely(args->fn)) {
1852		/*
1853		 * Put kthread fn, arg parameters in non-volatile GPRs in the
1854		 * switch frame so they are loaded by _switch before it returns
1855		 * to ret_from_kernel_thread.
1856		 */
1857		kregs->gpr[14] = ppc_function_entry((void *)args->fn);
1858		kregs->gpr[15] = (unsigned long)args->fn_arg;
1859	}
1860	p->thread.ksp = sp;
1861
1862#ifdef CONFIG_HAVE_HW_BREAKPOINT
1863	for (i = 0; i < nr_wp_slots(); i++)
1864		p->thread.ptrace_bps[i] = NULL;
1865#endif
1866
1867#ifdef CONFIG_PPC_FPU_REGS
1868	p->thread.fp_save_area = NULL;
1869#endif
1870#ifdef CONFIG_ALTIVEC
1871	p->thread.vr_save_area = NULL;
1872#endif
1873#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP)
1874	p->thread.kuap = KUAP_NONE;
1875#endif
1876#if defined(CONFIG_BOOKE) && defined(CONFIG_PPC_KUAP)
1877	p->thread.pid = MMU_NO_CONTEXT;
1878#endif
1879
1880	setup_ksp_vsid(p, sp);
1881
1882#ifdef CONFIG_PPC64 
1883	if (cpu_has_feature(CPU_FTR_DSCR)) {
1884		p->thread.dscr_inherit = current->thread.dscr_inherit;
1885		p->thread.dscr = mfspr(SPRN_DSCR);
1886	}
1887
1888	p->thread.tidr = 0;
1889#endif
1890#ifdef CONFIG_PPC_BOOK3S_64
1891	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
1892		p->thread.hashkeyr = current->thread.hashkeyr;
1893
1894	if (cpu_has_feature(CPU_FTR_ARCH_31))
1895		p->thread.dexcr = mfspr(SPRN_DEXCR);
1896#endif
1897	return 0;
1898}
1899
1900void preload_new_slb_context(unsigned long start, unsigned long sp);
1901
1902/*
1903 * Set up a thread for executing a new program
1904 */
1905void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
1906{
1907#ifdef CONFIG_PPC64
1908	unsigned long load_addr = regs->gpr[2];	/* saved by ELF_PLAT_INIT */
1909
1910	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled())
1911		preload_new_slb_context(start, sp);
1912#endif
1913
1914#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1915	/*
1916	 * Clear any transactional state, we're exec()ing. The cause is
1917	 * not important as there will never be a recheckpoint so it's not
1918	 * user visible.
1919	 */
1920	if (MSR_TM_SUSPENDED(mfmsr()))
1921		tm_reclaim_current(0);
1922#endif
1923
1924	memset(&regs->gpr[1], 0, sizeof(regs->gpr) - sizeof(regs->gpr[0]));
1925	regs->ctr = 0;
1926	regs->link = 0;
1927	regs->xer = 0;
1928	regs->ccr = 0;
1929	regs->gpr[1] = sp;
1930
1931#ifdef CONFIG_PPC32
1932	regs->mq = 0;
1933	regs->nip = start;
1934	regs->msr = MSR_USER;
1935#else
1936	if (!is_32bit_task()) {
1937		unsigned long entry;
1938
1939		if (is_elf2_task()) {
1940			/* Look ma, no function descriptors! */
1941			entry = start;
1942
1943			/*
1944			 * Ulrich says:
1945			 *   The latest iteration of the ABI requires that when
1946			 *   calling a function (at its global entry point),
1947			 *   the caller must ensure r12 holds the entry point
1948			 *   address (so that the function can quickly
1949			 *   establish addressability).
1950			 */
1951			regs->gpr[12] = start;
1952			/* Make sure that's restored on entry to userspace. */
1953			set_thread_flag(TIF_RESTOREALL);
1954		} else {
1955			unsigned long toc;
1956
1957			/* start is a relocated pointer to the function
1958			 * descriptor for the elf _start routine.  The first
1959			 * entry in the function descriptor is the entry
1960			 * address of _start and the second entry is the TOC
1961			 * value we need to use.
1962			 */
1963			__get_user(entry, (unsigned long __user *)start);
1964			__get_user(toc, (unsigned long __user *)start+1);
1965
1966			/* Check whether the e_entry function descriptor entries
1967			 * need to be relocated before we can use them.
1968			 */
1969			if (load_addr != 0) {
1970				entry += load_addr;
1971				toc   += load_addr;
1972			}
1973			regs->gpr[2] = toc;
1974		}
1975		regs_set_return_ip(regs, entry);
1976		regs_set_return_msr(regs, MSR_USER64);
1977	} else {
1978		regs->gpr[2] = 0;
1979		regs_set_return_ip(regs, start);
1980		regs_set_return_msr(regs, MSR_USER32);
1981	}
1982
1983#endif
1984#ifdef CONFIG_VSX
1985	current->thread.used_vsr = 0;
1986#endif
1987	current->thread.load_slb = 0;
1988	current->thread.load_fp = 0;
1989#ifdef CONFIG_PPC_FPU_REGS
1990	memset(&current->thread.fp_state, 0, sizeof(current->thread.fp_state));
1991	current->thread.fp_save_area = NULL;
1992#endif
1993#ifdef CONFIG_ALTIVEC
1994	memset(&current->thread.vr_state, 0, sizeof(current->thread.vr_state));
1995	current->thread.vr_state.vscr.u[3] = 0x00010000; /* Java mode disabled */
1996	current->thread.vr_save_area = NULL;
1997	current->thread.vrsave = 0;
1998	current->thread.used_vr = 0;
1999	current->thread.load_vec = 0;
2000#endif /* CONFIG_ALTIVEC */
2001#ifdef CONFIG_SPE
2002	memset(current->thread.evr, 0, sizeof(current->thread.evr));
2003	current->thread.acc = 0;
2004	current->thread.spefscr = 0;
2005	current->thread.used_spe = 0;
2006#endif /* CONFIG_SPE */
2007#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
2008	current->thread.tm_tfhar = 0;
2009	current->thread.tm_texasr = 0;
2010	current->thread.tm_tfiar = 0;
2011	current->thread.load_tm = 0;
2012#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
2013#ifdef CONFIG_PPC_BOOK3S_64
2014	if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE)) {
2015		current->thread.hashkeyr = get_random_long();
2016		mtspr(SPRN_HASHKEYR, current->thread.hashkeyr);
2017	}
2018#endif /* CONFIG_PPC_BOOK3S_64 */
2019}
2020EXPORT_SYMBOL(start_thread);
2021
2022#define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
2023		| PR_FP_EXC_RES | PR_FP_EXC_INV)
2024
2025int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
2026{
2027	struct pt_regs *regs = tsk->thread.regs;
2028
2029	/* This is a bit hairy.  If we are an SPE enabled  processor
2030	 * (have embedded fp) we store the IEEE exception enable flags in
2031	 * fpexc_mode.  fpexc_mode is also used for setting FP exception
2032	 * mode (asyn, precise, disabled) for 'Classic' FP. */
2033	if (val & PR_FP_EXC_SW_ENABLE) {
2034		if (cpu_has_feature(CPU_FTR_SPE)) {
2035			/*
2036			 * When the sticky exception bits are set
2037			 * directly by userspace, it must call prctl
2038			 * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
2039			 * in the existing prctl settings) or
2040			 * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
2041			 * the bits being set).  <fenv.h> functions
2042			 * saving and restoring the whole
2043			 * floating-point environment need to do so
2044			 * anyway to restore the prctl settings from
2045			 * the saved environment.
2046			 */
2047#ifdef CONFIG_SPE
2048			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
2049			tsk->thread.fpexc_mode = val &
2050				(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
2051#endif
2052			return 0;
2053		} else {
2054			return -EINVAL;
2055		}
2056	}
2057
2058	/* on a CONFIG_SPE this does not hurt us.  The bits that
2059	 * __pack_fe01 use do not overlap with bits used for
2060	 * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
2061	 * on CONFIG_SPE implementations are reserved so writing to
2062	 * them does not change anything */
2063	if (val > PR_FP_EXC_PRECISE)
2064		return -EINVAL;
2065	tsk->thread.fpexc_mode = __pack_fe01(val);
2066	if (regs != NULL && (regs->msr & MSR_FP) != 0) {
2067		regs_set_return_msr(regs, (regs->msr & ~(MSR_FE0|MSR_FE1))
2068						| tsk->thread.fpexc_mode);
2069	}
2070	return 0;
2071}
2072
2073int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
2074{
2075	unsigned int val = 0;
2076
2077	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) {
2078		if (cpu_has_feature(CPU_FTR_SPE)) {
2079			/*
2080			 * When the sticky exception bits are set
2081			 * directly by userspace, it must call prctl
2082			 * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
2083			 * in the existing prctl settings) or
2084			 * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
2085			 * the bits being set).  <fenv.h> functions
2086			 * saving and restoring the whole
2087			 * floating-point environment need to do so
2088			 * anyway to restore the prctl settings from
2089			 * the saved environment.
2090			 */
2091#ifdef CONFIG_SPE
2092			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
2093			val = tsk->thread.fpexc_mode;
2094#endif
2095		} else
2096			return -EINVAL;
2097	} else {
2098		val = __unpack_fe01(tsk->thread.fpexc_mode);
2099	}
2100	return put_user(val, (unsigned int __user *) adr);
2101}
2102
2103int set_endian(struct task_struct *tsk, unsigned int val)
2104{
2105	struct pt_regs *regs = tsk->thread.regs;
2106
2107	if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
2108	    (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
2109		return -EINVAL;
2110
2111	if (regs == NULL)
2112		return -EINVAL;
2113
2114	if (val == PR_ENDIAN_BIG)
2115		regs_set_return_msr(regs, regs->msr & ~MSR_LE);
2116	else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
2117		regs_set_return_msr(regs, regs->msr | MSR_LE);
2118	else
2119		return -EINVAL;
2120
2121	return 0;
2122}
2123
2124int get_endian(struct task_struct *tsk, unsigned long adr)
2125{
2126	struct pt_regs *regs = tsk->thread.regs;
2127	unsigned int val;
2128
2129	if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
2130	    !cpu_has_feature(CPU_FTR_REAL_LE))
2131		return -EINVAL;
2132
2133	if (regs == NULL)
2134		return -EINVAL;
2135
2136	if (regs->msr & MSR_LE) {
2137		if (cpu_has_feature(CPU_FTR_REAL_LE))
2138			val = PR_ENDIAN_LITTLE;
2139		else
2140			val = PR_ENDIAN_PPC_LITTLE;
2141	} else
2142		val = PR_ENDIAN_BIG;
2143
2144	return put_user(val, (unsigned int __user *)adr);
2145}
2146
2147int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
2148{
2149	tsk->thread.align_ctl = val;
2150	return 0;
2151}
2152
2153int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
2154{
2155	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
2156}
2157
2158static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
2159				  unsigned long nbytes)
2160{
2161	unsigned long stack_page;
2162	unsigned long cpu = task_cpu(p);
2163
2164	if (!hardirq_ctx[cpu] || !softirq_ctx[cpu])
2165		return 0;
2166
2167	stack_page = (unsigned long)hardirq_ctx[cpu];
2168	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2169		return 1;
2170
2171	stack_page = (unsigned long)softirq_ctx[cpu];
2172	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2173		return 1;
2174
2175	return 0;
2176}
2177
2178#ifdef CONFIG_PPC64
2179static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
2180					unsigned long nbytes)
2181{
 
2182	unsigned long stack_page;
2183	unsigned long cpu = task_cpu(p);
2184
2185	if (!paca_ptrs)
2186		return 0;
2187
2188	if (!paca_ptrs[cpu]->emergency_sp)
2189		return 0;
2190
2191# ifdef CONFIG_PPC_BOOK3S_64
2192	if (!paca_ptrs[cpu]->nmi_emergency_sp || !paca_ptrs[cpu]->mc_emergency_sp)
2193		return 0;
2194#endif
2195
2196	stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE;
2197	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2198		return 1;
2199
2200# ifdef CONFIG_PPC_BOOK3S_64
2201	stack_page = (unsigned long)paca_ptrs[cpu]->nmi_emergency_sp - THREAD_SIZE;
2202	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2203		return 1;
2204
2205	stack_page = (unsigned long)paca_ptrs[cpu]->mc_emergency_sp - THREAD_SIZE;
2206	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2207		return 1;
2208# endif
 
2209
2210	return 0;
2211}
2212#else
2213static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
2214					unsigned long nbytes)
2215{
2216	unsigned long stack_page;
2217	unsigned long cpu = task_cpu(p);
2218
2219	if (!IS_ENABLED(CONFIG_VMAP_STACK))
2220		return 0;
2221
2222	stack_page = (unsigned long)emergency_ctx[cpu] - THREAD_SIZE;
2223	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2224		return 1;
2225
2226	return 0;
2227}
2228#endif
2229
2230/*
2231 * validate the stack frame of a particular minimum size, used for when we are
2232 * looking at a certain object in the stack beyond the minimum.
2233 */
2234int validate_sp_size(unsigned long sp, struct task_struct *p,
2235		     unsigned long nbytes)
2236{
2237	unsigned long stack_page = (unsigned long)task_stack_page(p);
2238
2239	if (sp < THREAD_SIZE)
2240		return 0;
2241
2242	if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
2243		return 1;
2244
2245	if (valid_irq_stack(sp, p, nbytes))
2246		return 1;
2247
2248	return valid_emergency_stack(sp, p, nbytes);
2249}
2250
2251int validate_sp(unsigned long sp, struct task_struct *p)
2252{
2253	return validate_sp_size(sp, p, STACK_FRAME_MIN_SIZE);
2254}
2255
2256static unsigned long ___get_wchan(struct task_struct *p)
2257{
2258	unsigned long ip, sp;
2259	int count = 0;
2260
2261	sp = p->thread.ksp;
2262	if (!validate_sp(sp, p))
2263		return 0;
2264
2265	do {
2266		sp = READ_ONCE_NOCHECK(*(unsigned long *)sp);
2267		if (!validate_sp(sp, p) || task_is_running(p))
2268			return 0;
2269		if (count > 0) {
2270			ip = READ_ONCE_NOCHECK(((unsigned long *)sp)[STACK_FRAME_LR_SAVE]);
2271			if (!in_sched_functions(ip))
2272				return ip;
2273		}
2274	} while (count++ < 16);
2275	return 0;
2276}
2277
2278unsigned long __get_wchan(struct task_struct *p)
2279{
2280	unsigned long ret;
2281
2282	if (!try_get_task_stack(p))
2283		return 0;
2284
2285	ret = ___get_wchan(p);
2286
2287	put_task_stack(p);
2288
2289	return ret;
2290}
2291
2292static bool empty_user_regs(struct pt_regs *regs, struct task_struct *tsk)
2293{
2294	unsigned long stack_page;
2295
2296	// A non-empty pt_regs should never have a zero MSR or TRAP value.
2297	if (regs->msr || regs->trap)
2298		return false;
2299
2300	// Check it sits at the very base of the stack
2301	stack_page = (unsigned long)task_stack_page(tsk);
2302	if ((unsigned long)(regs + 1) != stack_page + THREAD_SIZE)
2303		return false;
2304
2305	return true;
2306}
2307
2308static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
2309
2310void __no_sanitize_address show_stack(struct task_struct *tsk,
2311				      unsigned long *stack,
2312				      const char *loglvl)
2313{
2314	unsigned long sp, ip, lr, newsp;
2315	int count = 0;
2316	int firstframe = 1;
2317	unsigned long ret_addr;
2318	int ftrace_idx = 0;
2319
2320	if (tsk == NULL)
2321		tsk = current;
2322
2323	if (!try_get_task_stack(tsk))
2324		return;
2325
2326	sp = (unsigned long) stack;
2327	if (sp == 0) {
2328		if (tsk == current)
2329			sp = current_stack_frame();
2330		else
2331			sp = tsk->thread.ksp;
2332	}
2333
2334	lr = 0;
2335	printk("%sCall Trace:\n", loglvl);
2336	do {
2337		if (!validate_sp(sp, tsk))
2338			break;
2339
2340		stack = (unsigned long *) sp;
2341		newsp = stack[0];
2342		ip = stack[STACK_FRAME_LR_SAVE];
2343		if (!firstframe || ip != lr) {
2344			printk("%s["REG"] ["REG"] %pS",
2345				loglvl, sp, ip, (void *)ip);
2346			ret_addr = ftrace_graph_ret_addr(current,
2347						&ftrace_idx, ip, stack);
2348			if (ret_addr != ip)
2349				pr_cont(" (%pS)", (void *)ret_addr);
2350			if (firstframe)
2351				pr_cont(" (unreliable)");
2352			pr_cont("\n");
2353		}
2354		firstframe = 0;
2355
2356		/*
2357		 * See if this is an exception frame.
2358		 * We look for the "regs" marker in the current frame.
2359		 *
2360		 * STACK_SWITCH_FRAME_SIZE being the smallest frame that
2361		 * could hold a pt_regs, if that does not fit then it can't
2362		 * have regs.
2363		 */
2364		if (validate_sp_size(sp, tsk, STACK_SWITCH_FRAME_SIZE)
2365		    && stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
2366			struct pt_regs *regs = (struct pt_regs *)
2367				(sp + STACK_INT_FRAME_REGS);
2368
2369			lr = regs->link;
2370			printk("%s--- interrupt: %lx at %pS\n",
2371			       loglvl, regs->trap, (void *)regs->nip);
2372
2373			// Detect the case of an empty pt_regs at the very base
2374			// of the stack and suppress showing it in full.
2375			if (!empty_user_regs(regs, tsk)) {
2376				__show_regs(regs);
2377				printk("%s--- interrupt: %lx\n", loglvl, regs->trap);
2378			}
2379
2380			firstframe = 1;
2381		}
2382
2383		sp = newsp;
2384	} while (count++ < kstack_depth_to_print);
2385
2386	put_task_stack(tsk);
2387}
2388
2389#ifdef CONFIG_PPC64
2390/* Called with hard IRQs off */
2391void notrace __ppc64_runlatch_on(void)
2392{
2393	struct thread_info *ti = current_thread_info();
2394
2395	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
2396		/*
2397		 * Least significant bit (RUN) is the only writable bit of
2398		 * the CTRL register, so we can avoid mfspr. 2.06 is not the
2399		 * earliest ISA where this is the case, but it's convenient.
2400		 */
2401		mtspr(SPRN_CTRLT, CTRL_RUNLATCH);
2402	} else {
2403		unsigned long ctrl;
2404
2405		/*
2406		 * Some architectures (e.g., Cell) have writable fields other
2407		 * than RUN, so do the read-modify-write.
2408		 */
2409		ctrl = mfspr(SPRN_CTRLF);
2410		ctrl |= CTRL_RUNLATCH;
2411		mtspr(SPRN_CTRLT, ctrl);
2412	}
2413
2414	ti->local_flags |= _TLF_RUNLATCH;
2415}
2416
2417/* Called with hard IRQs off */
2418void notrace __ppc64_runlatch_off(void)
2419{
2420	struct thread_info *ti = current_thread_info();
2421
2422	ti->local_flags &= ~_TLF_RUNLATCH;
2423
2424	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
2425		mtspr(SPRN_CTRLT, 0);
2426	} else {
2427		unsigned long ctrl;
2428
2429		ctrl = mfspr(SPRN_CTRLF);
2430		ctrl &= ~CTRL_RUNLATCH;
2431		mtspr(SPRN_CTRLT, ctrl);
2432	}
2433}
2434#endif /* CONFIG_PPC64 */
2435
2436unsigned long arch_align_stack(unsigned long sp)
2437{
2438	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
2439		sp -= get_random_u32_below(PAGE_SIZE);
2440	return sp & ~0xf;
2441}