traps.c 24.5 KB
Newer Older
James Hogan's avatar
James Hogan committed
1 2 3 4 5 6 7 8 9 10
/*
 *  Meta exception handling.
 *
 *  Copyright (C) 2005,2006,2007,2008,2009,2012 Imagination Technologies Ltd.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

11
#include <linux/export.h>
James Hogan's avatar
James Hogan committed
12 13 14 15 16 17 18
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/interrupt.h>
19
#include <linux/preempt.h>
James Hogan's avatar
James Hogan committed
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62
#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/kdebug.h>
#include <linux/kexec.h>
#include <linux/unistd.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/syscalls.h>

#include <asm/bug.h>
#include <asm/core_reg.h>
#include <asm/irqflags.h>
#include <asm/siginfo.h>
#include <asm/traps.h>
#include <asm/hwthread.h>
#include <asm/switch.h>
#include <asm/user_gateway.h>
#include <asm/syscall.h>
#include <asm/syscalls.h>

/* Passing syscall arguments as long long is quicker. */
typedef unsigned int (*LPSYSCALL) (unsigned long long,
				   unsigned long long,
				   unsigned long long);

/*
 * Users of LNKSET should compare the bus error bits obtained from DEFR
 * against TXDEFR_LNKSET_SUCCESS only as the failure code will vary between
 * different cores revisions.
 */
#define TXDEFR_LNKSET_SUCCESS 0x02000000
#define TXDEFR_LNKSET_FAILURE 0x04000000

/*
 * Our global TBI handle.  Initialised from setup.c/setup_arch.
 */
DECLARE_PER_CPU(PTBI, pTBI);

#ifdef CONFIG_SMP
static DEFINE_PER_CPU(unsigned int, trigger_mask);
#else
unsigned int global_trigger_mask;
63
EXPORT_SYMBOL(global_trigger_mask);
James Hogan's avatar
James Hogan committed
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
#endif

unsigned long per_cpu__stack_save[NR_CPUS];

static const char * const trap_names[] = {
	[TBIXXF_SIGNUM_IIF] = "Illegal instruction fault",
	[TBIXXF_SIGNUM_PGF] = "Privilege violation",
	[TBIXXF_SIGNUM_DHF] = "Unaligned data access fault",
	[TBIXXF_SIGNUM_IGF] = "Code fetch general read failure",
	[TBIXXF_SIGNUM_DGF] = "Data access general read/write fault",
	[TBIXXF_SIGNUM_IPF] = "Code fetch page fault",
	[TBIXXF_SIGNUM_DPF] = "Data access page fault",
	[TBIXXF_SIGNUM_IHF] = "Instruction breakpoint",
	[TBIXXF_SIGNUM_DWF] = "Read-only data access fault",
};

const char *trap_name(int trapno)
{
	if (trapno >= 0 && trapno < ARRAY_SIZE(trap_names)
			&& trap_names[trapno])
		return trap_names[trapno];
	return "Unknown fault";
}

static DEFINE_SPINLOCK(die_lock);

void die(const char *str, struct pt_regs *regs, long err,
	 unsigned long addr)
{
	static int die_counter;

	oops_enter();

	spin_lock_irq(&die_lock);
	console_verbose();
	bust_spinlocks(1);
	pr_err("%s: err %04lx (%s) addr %08lx [#%d]\n", str, err & 0xffff,
	       trap_name(err & 0xffff), addr, ++die_counter);

	print_modules();
	show_regs(regs);

	pr_err("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
	       task_pid_nr(current), task_stack_page(current) + THREAD_SIZE);

	bust_spinlocks(0);
	add_taint(TAINT_DIE);
	if (kexec_should_crash(current))
		crash_kexec(regs);

	if (in_interrupt())
		panic("Fatal exception in interrupt");

	if (panic_on_oops)
		panic("Fatal exception");

	spin_unlock_irq(&die_lock);
	oops_exit();
	do_exit(SIGSEGV);
}

#ifdef CONFIG_METAG_DSP
/*
 * The ECH encoding specifies the size of a DSPRAM as,
 *
 *		"slots" / 4
 *
 * A "slot" is the size of two DSPRAM bank entries; an entry from
 * DSPRAM bank A and an entry from DSPRAM bank B. One DSPRAM bank
 * entry is 4 bytes.
 */
#define SLOT_SZ	8
static inline unsigned int decode_dspram_size(unsigned int size)
{
	unsigned int _sz = size & 0x7f;

	return _sz * SLOT_SZ * 4;
}

static void dspram_save(struct meta_ext_context *dsp_ctx,
			unsigned int ramA_sz, unsigned int ramB_sz)
{
	unsigned int ram_sz[2];
	int i;

	ram_sz[0] = ramA_sz;
	ram_sz[1] = ramB_sz;

	for (i = 0; i < 2; i++) {
		if (ram_sz[i] != 0) {
			unsigned int sz;

			if (i == 0)
				sz = decode_dspram_size(ram_sz[i] >> 8);
			else
				sz = decode_dspram_size(ram_sz[i]);

			if (dsp_ctx->ram[i] == NULL) {
				dsp_ctx->ram[i] = kmalloc(sz, GFP_KERNEL);

				if (dsp_ctx->ram[i] == NULL)
					panic("couldn't save DSP context");
			} else {
				if (ram_sz[i] > dsp_ctx->ram_sz[i]) {
					kfree(dsp_ctx->ram[i]);

					dsp_ctx->ram[i] = kmalloc(sz,
								  GFP_KERNEL);

					if (dsp_ctx->ram[i] == NULL)
						panic("couldn't save DSP context");
				}
			}

			if (i == 0)
				__TBIDspramSaveA(ram_sz[i], dsp_ctx->ram[i]);
			else
				__TBIDspramSaveB(ram_sz[i], dsp_ctx->ram[i]);

			dsp_ctx->ram_sz[i] = ram_sz[i];
		}
	}
}
#endif /* CONFIG_METAG_DSP */

/*
 * Allow interrupts to be nested and save any "extended" register
 * context state, e.g. DSP regs and RAMs.
 */
static void nest_interrupts(TBIRES State, unsigned long mask)
{
#ifdef CONFIG_METAG_DSP
	struct meta_ext_context *dsp_ctx;
	unsigned int D0_8;

	/*
	 * D0.8 may contain an ECH encoding. The upper 16 bits
	 * tell us what DSP resources the current process is
	 * using. OR the bits into the SaveMask so that
	 * __TBINestInts() knows what resources to save as
	 * part of this context.
	 *
	 * Don't save the context if we're nesting interrupts in the
	 * kernel because the kernel doesn't use DSP hardware.
	 */
	D0_8 = __core_reg_get(D0.8);

	if (D0_8 && (State.Sig.SaveMask & TBICTX_PRIV_BIT)) {
		State.Sig.SaveMask |= (D0_8 >> 16);

		dsp_ctx = current->thread.dsp_context;
		if (dsp_ctx == NULL) {
			dsp_ctx = kzalloc(sizeof(*dsp_ctx), GFP_KERNEL);
			if (dsp_ctx == NULL)
				panic("couldn't save DSP context: ENOMEM");

			current->thread.dsp_context = dsp_ctx;
		}

		current->thread.user_flags |= (D0_8 & 0xffff0000);
		__TBINestInts(State, &dsp_ctx->regs, mask);
		dspram_save(dsp_ctx, D0_8 & 0x7f00, D0_8 & 0x007f);
	} else
		__TBINestInts(State, NULL, mask);
#else
	__TBINestInts(State, NULL, mask);
#endif
}

void head_end(TBIRES State, unsigned long mask)
{
	unsigned int savemask = (unsigned short)State.Sig.SaveMask;
	unsigned int ctx_savemask = (unsigned short)State.Sig.pCtx->SaveMask;

	if (savemask & TBICTX_PRIV_BIT) {
		ctx_savemask |= TBICTX_PRIV_BIT;
		current->thread.user_flags = savemask;
	}

	/* Always undo the sleep bit */
	ctx_savemask &= ~TBICTX_WAIT_BIT;

	/* Always save the catch buffer and RD pipe if they are dirty */
	savemask |= TBICTX_XCBF_BIT;

	/* Only save the catch and RD if we have not already done so.
	 * Note - the RD bits are in the pCtx only, and not in the
	 * State.SaveMask.
	 */
	if ((savemask & TBICTX_CBUF_BIT) ||
	    (ctx_savemask & TBICTX_CBRP_BIT)) {
		/* Have we already saved the buffers though?
		 * - See TestTrack 5071 */
		if (ctx_savemask & TBICTX_XCBF_BIT) {
			/* Strip off the bits so the call to __TBINestInts
			 * won't save the buffers again. */
			savemask &= ~TBICTX_CBUF_BIT;
			ctx_savemask &= ~TBICTX_CBRP_BIT;
		}
	}

#ifdef CONFIG_METAG_META21
	{
		unsigned int depth, txdefr;

		/*
		 * Save TXDEFR state.
		 *
		 * The process may have been interrupted after a LNKSET, but
		 * before it could read the DEFR state, so we mustn't lose that
		 * state or it could end up retrying an atomic operation that
		 * succeeded.
		 *
		 * All interrupts are disabled at this point so we
		 * don't need to perform any locking. We must do this
		 * dance before we use LNKGET or LNKSET.
		 */
		BUG_ON(current->thread.int_depth > HARDIRQ_BITS);

		depth = current->thread.int_depth++;

		txdefr = __core_reg_get(TXDEFR);

		txdefr &= TXDEFR_BUS_STATE_BITS;
		if (txdefr & TXDEFR_LNKSET_SUCCESS)
			current->thread.txdefr_failure &= ~(1 << depth);
		else
			current->thread.txdefr_failure |= (1 << depth);
	}
#endif

	State.Sig.SaveMask = savemask;
	State.Sig.pCtx->SaveMask = ctx_savemask;

	nest_interrupts(State, mask);

#ifdef CONFIG_METAG_POISON_CATCH_BUFFERS
	/* Poison the catch registers.  This shows up any mistakes we have
	 * made in their handling MUCH quicker.
	 */
	__core_reg_set(TXCATCH0, 0x87650021);
	__core_reg_set(TXCATCH1, 0x87654322);
	__core_reg_set(TXCATCH2, 0x87654323);
	__core_reg_set(TXCATCH3, 0x87654324);
#endif /* CONFIG_METAG_POISON_CATCH_BUFFERS */
}

TBIRES tail_end_sys(TBIRES State, int syscall, int *restart)
{
	struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;
	unsigned long flags;

	local_irq_disable();

	if (user_mode(regs)) {
		flags = current_thread_info()->flags;
		if (flags & _TIF_WORK_MASK &&
		    do_work_pending(regs, flags, syscall)) {
			*restart = 1;
			return State;
		}

#ifdef CONFIG_METAG_FPU
		if (current->thread.fpu_context &&
		    current->thread.fpu_context->needs_restore) {
			__TBICtxFPURestore(State, current->thread.fpu_context);
			/*
			 * Clearing this bit ensures the FP unit is not made
			 * active again unless it is used.
			 */
			State.Sig.SaveMask &= ~TBICTX_FPAC_BIT;
			current->thread.fpu_context->needs_restore = false;
		}
		State.Sig.TrigMask |= TBI_TRIG_BIT(TBID_SIGNUM_DFR);
#endif
	}

	/* TBI will turn interrupts back on at some point. */
	if (!irqs_disabled_flags((unsigned long)State.Sig.TrigMask))
		trace_hardirqs_on();

#ifdef CONFIG_METAG_DSP
	/*
	 * If we previously saved an extended context then restore it
	 * now. Otherwise, clear D0.8 because this process is not
	 * using DSP hardware.
	 */
	if (State.Sig.pCtx->SaveMask & TBICTX_XEXT_BIT) {
		unsigned int D0_8;
		struct meta_ext_context *dsp_ctx = current->thread.dsp_context;

		/* Make sure we're going to return to userland. */
		BUG_ON(current->thread.int_depth != 1);

		if (dsp_ctx->ram_sz[0] > 0)
			__TBIDspramRestoreA(dsp_ctx->ram_sz[0],
					    dsp_ctx->ram[0]);
		if (dsp_ctx->ram_sz[1] > 0)
			__TBIDspramRestoreB(dsp_ctx->ram_sz[1],
					    dsp_ctx->ram[1]);

		State.Sig.SaveMask |= State.Sig.pCtx->SaveMask;
		__TBICtxRestore(State, current->thread.dsp_context);
		D0_8 = __core_reg_get(D0.8);
		D0_8 |= current->thread.user_flags & 0xffff0000;
		D0_8 |= (dsp_ctx->ram_sz[1] | dsp_ctx->ram_sz[0]) & 0xffff;
		__core_reg_set(D0.8, D0_8);
	} else
		__core_reg_set(D0.8, 0);
#endif /* CONFIG_METAG_DSP */

#ifdef CONFIG_METAG_META21
	{
		unsigned int depth, txdefr;

		/*
		 * If there hasn't been a LNKSET since the last LNKGET then the
		 * link flag will be set, causing the next LNKSET to succeed if
		 * the addresses match. The two LNK operations may not be a pair
		 * (e.g. see atomic_read()), so the LNKSET should fail.
		 * We use a conditional-never LNKSET to clear the link flag
		 * without side effects.
		 */
		asm volatile("LNKSETDNV [D0Re0],D0Re0");

		depth = --current->thread.int_depth;

		BUG_ON(user_mode(regs) && depth);

		txdefr = __core_reg_get(TXDEFR);

		txdefr &= ~TXDEFR_BUS_STATE_BITS;

		/* Do we need to restore a failure code into TXDEFR? */
		if (current->thread.txdefr_failure & (1 << depth))
			txdefr |= (TXDEFR_LNKSET_FAILURE | TXDEFR_BUS_TRIG_BIT);
		else
			txdefr |= (TXDEFR_LNKSET_SUCCESS | TXDEFR_BUS_TRIG_BIT);

		__core_reg_set(TXDEFR, txdefr);
	}
#endif
	return State;
}

#ifdef CONFIG_SMP
/*
 * If we took an interrupt in the middle of __kuser_get_tls then we need
 * to rewind the PC to the start of the function in case the process
 * gets migrated to another thread (SMP only) and it reads the wrong tls
 * data.
 */
static inline void _restart_critical_section(TBIRES State)
{
	unsigned long get_tls_start;
	unsigned long get_tls_end;

	get_tls_start = (unsigned long)__kuser_get_tls -
		(unsigned long)&__user_gateway_start;

	get_tls_start += USER_GATEWAY_PAGE;

	get_tls_end = (unsigned long)__kuser_get_tls_end -
		(unsigned long)&__user_gateway_start;

	get_tls_end += USER_GATEWAY_PAGE;

	if ((State.Sig.pCtx->CurrPC >= get_tls_start) &&
	    (State.Sig.pCtx->CurrPC < get_tls_end))
		State.Sig.pCtx->CurrPC = get_tls_start;
}
#else
/*
 * If we took an interrupt in the middle of
 * __kuser_cmpxchg then we need to rewind the PC to the
 * start of the function.
 */
static inline void _restart_critical_section(TBIRES State)
{
	unsigned long cmpxchg_start;
	unsigned long cmpxchg_end;

	cmpxchg_start = (unsigned long)__kuser_cmpxchg -
		(unsigned long)&__user_gateway_start;

	cmpxchg_start += USER_GATEWAY_PAGE;

	cmpxchg_end = (unsigned long)__kuser_cmpxchg_end -
		(unsigned long)&__user_gateway_start;

	cmpxchg_end += USER_GATEWAY_PAGE;

	if ((State.Sig.pCtx->CurrPC >= cmpxchg_start) &&
	    (State.Sig.pCtx->CurrPC < cmpxchg_end))
		State.Sig.pCtx->CurrPC = cmpxchg_start;
}
#endif

/* Used by kick_handler() */
void restart_critical_section(TBIRES State)
{
	_restart_critical_section(State);
}

TBIRES trigger_handler(TBIRES State, int SigNum, int Triggers, int Inst,
		       PTBI pTBI)
{
	head_end(State, ~INTS_OFF_MASK);

	/* If we interrupted user code handle any critical sections. */
	if (State.Sig.SaveMask & TBICTX_PRIV_BIT)
		_restart_critical_section(State);

	trace_hardirqs_off();

	do_IRQ(SigNum, (struct pt_regs *)State.Sig.pCtx);

	return tail_end(State);
}

static unsigned int load_fault(PTBICTXEXTCB0 pbuf)
{
	return pbuf->CBFlags & TXCATCH0_READ_BIT;
}

static unsigned long fault_address(PTBICTXEXTCB0 pbuf)
{
	return pbuf->CBAddr;
}

static void unhandled_fault(struct pt_regs *regs, unsigned long addr,
			    int signo, int code, int trapno)
{
	if (user_mode(regs)) {
		siginfo_t info;

		if (show_unhandled_signals && unhandled_signal(current, signo)
		    && printk_ratelimit()) {

			pr_info("pid %d unhandled fault: pc 0x%08x, addr 0x%08lx, trap %d (%s)\n",
				current->pid, regs->ctx.CurrPC, addr,
				trapno, trap_name(trapno));
			print_vma_addr(" in ", regs->ctx.CurrPC);
			print_vma_addr(" rtp in ", regs->ctx.DX[4].U1);
			printk("\n");
			show_regs(regs);
		}

		info.si_signo = signo;
		info.si_errno = 0;
		info.si_code = code;
		info.si_addr = (__force void __user *)addr;
		info.si_trapno = trapno;
		force_sig_info(signo, &info, current);
	} else {
		die("Oops", regs, trapno, addr);
	}
}

static int handle_data_fault(PTBICTXEXTCB0 pcbuf, struct pt_regs *regs,
			     unsigned int data_address, int trapno)
{
	int ret;

	ret = do_page_fault(regs, data_address, !load_fault(pcbuf), trapno);

	return ret;
}

static unsigned long get_inst_fault_address(struct pt_regs *regs)
{
	return regs->ctx.CurrPC;
}

TBIRES fault_handler(TBIRES State, int SigNum, int Triggers,
		     int Inst, PTBI pTBI)
{
	struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;
	PTBICTXEXTCB0 pcbuf = (PTBICTXEXTCB0)&regs->extcb0;
	unsigned long data_address;

	head_end(State, ~INTS_OFF_MASK);

	/* Hardware breakpoint or data watch */
	if ((SigNum == TBIXXF_SIGNUM_IHF) ||
	    ((SigNum == TBIXXF_SIGNUM_DHF) &&
	     (pcbuf[0].CBFlags & (TXCATCH0_WATCH1_BIT |
				  TXCATCH0_WATCH0_BIT)))) {
		State = __TBIUnExpXXX(State, SigNum, Triggers, Inst,
				      pTBI);
		return tail_end(State);
	}

	local_irq_enable();

	data_address = fault_address(pcbuf);

	switch (SigNum) {
	case TBIXXF_SIGNUM_IGF:
		/* 1st-level entry invalid (instruction fetch) */
	case TBIXXF_SIGNUM_IPF: {
		/* 2nd-level entry invalid (instruction fetch) */
		unsigned long addr = get_inst_fault_address(regs);
		do_page_fault(regs, addr, 0, SigNum);
		break;
	}

	case TBIXXF_SIGNUM_DGF:
		/* 1st-level entry invalid (data access) */
	case TBIXXF_SIGNUM_DPF:
		/* 2nd-level entry invalid (data access) */
	case TBIXXF_SIGNUM_DWF:
		/* Write to read only page */
		handle_data_fault(pcbuf, regs, data_address, SigNum);
		break;

	case TBIXXF_SIGNUM_IIF:
		/* Illegal instruction */
		unhandled_fault(regs, regs->ctx.CurrPC, SIGILL, ILL_ILLOPC,
				SigNum);
		break;

	case TBIXXF_SIGNUM_DHF:
		/* Unaligned access */
		unhandled_fault(regs, data_address, SIGBUS, BUS_ADRALN,
				SigNum);
		break;
	case TBIXXF_SIGNUM_PGF:
		/* Privilege violation */
		unhandled_fault(regs, data_address, SIGSEGV, SEGV_ACCERR,
				SigNum);
		break;
	default:
		BUG();
		break;
	}

	return tail_end(State);
}

static bool switch_is_syscall(unsigned int inst)
{
	return inst == __METAG_SW_ENCODING(SYS);
}

static bool switch_is_legacy_syscall(unsigned int inst)
{
	return inst == __METAG_SW_ENCODING(SYS_LEGACY);
}

static inline void step_over_switch(struct pt_regs *regs, unsigned int inst)
{
	regs->ctx.CurrPC += 4;
}

static inline int test_syscall_work(void)
{
	return current_thread_info()->flags & _TIF_WORK_SYSCALL_MASK;
}

TBIRES switch1_handler(TBIRES State, int SigNum, int Triggers,
		       int Inst, PTBI pTBI)
{
	struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;
	unsigned int sysnumber;
	unsigned long long a1_a2, a3_a4, a5_a6;
	LPSYSCALL syscall_entry;
	int restart;

	head_end(State, ~INTS_OFF_MASK);

	/*
	 * If this is not a syscall SWITCH it could be a breakpoint.
	 */
	if (!switch_is_syscall(Inst)) {
		/*
		 * Alert the user if they're trying to use legacy system
		 * calls. This suggests they need to update their C
		 * library and build against up to date kernel headers.
		 */
		if (switch_is_legacy_syscall(Inst))
			pr_warn_once("WARNING: A legacy syscall was made. Your userland needs updating.\n");
		/*
		 * We don't know how to handle the SWITCH and cannot
		 * safely ignore it, so treat all unknown switches
		 * (including breakpoints) as traps.
		 */
		force_sig(SIGTRAP, current);
		return tail_end(State);
	}

	local_irq_enable();

restart_syscall:
	restart = 0;
	sysnumber = regs->ctx.DX[0].U1;

	if (test_syscall_work())
		sysnumber = syscall_trace_enter(regs);

	/* Skip over the SWITCH instruction - or you just get 'stuck' on it! */
	step_over_switch(regs, Inst);

	if (sysnumber >= __NR_syscalls) {
		pr_debug("unknown syscall number: %d\n", sysnumber);
		syscall_entry = (LPSYSCALL) sys_ni_syscall;
	} else {
		syscall_entry = (LPSYSCALL) sys_call_table[sysnumber];
	}

	/* Use 64bit loads for speed. */
	a5_a6 = *(unsigned long long *)&regs->ctx.DX[1];
	a3_a4 = *(unsigned long long *)&regs->ctx.DX[2];
	a1_a2 = *(unsigned long long *)&regs->ctx.DX[3];

	/* here is the actual call to the syscall handler functions */
	regs->ctx.DX[0].U0 = syscall_entry(a1_a2, a3_a4, a5_a6);

	if (test_syscall_work())
		syscall_trace_leave(regs);

	State = tail_end_sys(State, sysnumber, &restart);
	/* Handlerless restarts shouldn't go via userland */
	if (restart)
		goto restart_syscall;
	return State;
}

TBIRES switchx_handler(TBIRES State, int SigNum, int Triggers,
		       int Inst, PTBI pTBI)
{
	struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;

	/*
	 * This can be caused by any user process simply executing an unusual
	 * SWITCH instruction. If there's no DA, __TBIUnExpXXX will cause the
	 * thread to stop, so signal a SIGTRAP instead.
	 */
	head_end(State, ~INTS_OFF_MASK);
	if (user_mode(regs))
		force_sig(SIGTRAP, current);
	else
		State = __TBIUnExpXXX(State, SigNum, Triggers, Inst, pTBI);
	return tail_end(State);
}

#ifdef CONFIG_METAG_META21
TBIRES fpe_handler(TBIRES State, int SigNum, int Triggers, int Inst, PTBI pTBI)
{
	struct pt_regs *regs = (struct pt_regs *)State.Sig.pCtx;
	unsigned int error_state = Triggers;
	siginfo_t info;

	head_end(State, ~INTS_OFF_MASK);

	local_irq_enable();

	info.si_signo = SIGFPE;

	if (error_state & TXSTAT_FPE_INVALID_BIT)
		info.si_code = FPE_FLTINV;
	else if (error_state & TXSTAT_FPE_DIVBYZERO_BIT)
		info.si_code = FPE_FLTDIV;
	else if (error_state & TXSTAT_FPE_OVERFLOW_BIT)
		info.si_code = FPE_FLTOVF;
	else if (error_state & TXSTAT_FPE_UNDERFLOW_BIT)
		info.si_code = FPE_FLTUND;
	else if (error_state & TXSTAT_FPE_INEXACT_BIT)
		info.si_code = FPE_FLTRES;
	else
		info.si_code = 0;
	info.si_errno = 0;
	info.si_addr = (__force void __user *)regs->ctx.CurrPC;
	force_sig_info(SIGFPE, &info, current);

	return tail_end(State);
}
#endif

#ifdef CONFIG_METAG_SUSPEND_MEM
struct traps_context {
	PTBIAPIFN fnSigs[TBID_SIGNUM_MAX + 1];
};

static struct traps_context *metag_traps_context;

int traps_save_context(void)
{
	unsigned long cpu = smp_processor_id();
	PTBI _pTBI = per_cpu(pTBI, cpu);
	struct traps_context *context;

	context = kzalloc(sizeof(*context), GFP_ATOMIC);
	if (!context)
		return -ENOMEM;

	memcpy(context->fnSigs, (void *)_pTBI->fnSigs, sizeof(context->fnSigs));

	metag_traps_context = context;
	return 0;
}

int traps_restore_context(void)
{
	unsigned long cpu = smp_processor_id();
	PTBI _pTBI = per_cpu(pTBI, cpu);
	struct traps_context *context = metag_traps_context;

	metag_traps_context = NULL;

	memcpy((void *)_pTBI->fnSigs, context->fnSigs, sizeof(context->fnSigs));

	kfree(context);
	return 0;
}
#endif

#ifdef CONFIG_SMP
782
static inline unsigned int _get_trigger_mask(void)
James Hogan's avatar
James Hogan committed
783 784 785 786 787
{
	unsigned long cpu = smp_processor_id();
	return per_cpu(trigger_mask, cpu);
}

788 789 790 791
unsigned int get_trigger_mask(void)
{
	return _get_trigger_mask();
}
792
EXPORT_SYMBOL(get_trigger_mask);
793

James Hogan's avatar
James Hogan committed
794 795 796 797 798
static void set_trigger_mask(unsigned int mask)
{
	unsigned long cpu = smp_processor_id();
	per_cpu(trigger_mask, cpu) = mask;
}
799 800 801 802 803 804 805 806

void arch_local_irq_enable(void)
{
	preempt_disable();
	arch_local_irq_restore(_get_trigger_mask());
	preempt_enable_no_resched();
}
EXPORT_SYMBOL(arch_local_irq_enable);
James Hogan's avatar
James Hogan committed
807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995
#else
static void set_trigger_mask(unsigned int mask)
{
	global_trigger_mask = mask;
}
#endif

void __cpuinit per_cpu_trap_init(unsigned long cpu)
{
	TBIRES int_context;
	unsigned int thread = cpu_2_hwthread_id[cpu];

	set_trigger_mask(TBI_INTS_INIT(thread) | /* interrupts */
			 TBI_TRIG_BIT(TBID_SIGNUM_LWK) | /* low level kick */
			 TBI_TRIG_BIT(TBID_SIGNUM_SW1) |
			 TBI_TRIG_BIT(TBID_SIGNUM_SWS));

	/* non-priv - use current stack */
	int_context.Sig.pCtx = NULL;
	/* Start with interrupts off */
	int_context.Sig.TrigMask = INTS_OFF_MASK;
	int_context.Sig.SaveMask = 0;

	/* And call __TBIASyncTrigger() */
	__TBIASyncTrigger(int_context);
}

void __init trap_init(void)
{
	unsigned long cpu = smp_processor_id();
	PTBI _pTBI = per_cpu(pTBI, cpu);

	_pTBI->fnSigs[TBID_SIGNUM_XXF] = fault_handler;
	_pTBI->fnSigs[TBID_SIGNUM_SW0] = switchx_handler;
	_pTBI->fnSigs[TBID_SIGNUM_SW1] = switch1_handler;
	_pTBI->fnSigs[TBID_SIGNUM_SW2] = switchx_handler;
	_pTBI->fnSigs[TBID_SIGNUM_SW3] = switchx_handler;
	_pTBI->fnSigs[TBID_SIGNUM_SWK] = kick_handler;

#ifdef CONFIG_METAG_META21
	_pTBI->fnSigs[TBID_SIGNUM_DFR] = __TBIHandleDFR;
	_pTBI->fnSigs[TBID_SIGNUM_FPE] = fpe_handler;
#endif

	per_cpu_trap_init(cpu);
}

void tbi_startup_interrupt(int irq)
{
	unsigned long cpu = smp_processor_id();
	PTBI _pTBI = per_cpu(pTBI, cpu);

	BUG_ON(irq > TBID_SIGNUM_MAX);

	/* For TR1 and TR2, the thread id is encoded in the irq number */
	if (irq >= TBID_SIGNUM_T10 && irq < TBID_SIGNUM_TR3)
		cpu = hwthread_id_2_cpu[(irq - TBID_SIGNUM_T10) % 4];

	set_trigger_mask(get_trigger_mask() | TBI_TRIG_BIT(irq));

	_pTBI->fnSigs[irq] = trigger_handler;
}

void tbi_shutdown_interrupt(int irq)
{
	unsigned long cpu = smp_processor_id();
	PTBI _pTBI = per_cpu(pTBI, cpu);

	BUG_ON(irq > TBID_SIGNUM_MAX);

	set_trigger_mask(get_trigger_mask() & ~TBI_TRIG_BIT(irq));

	_pTBI->fnSigs[irq] = __TBIUnExpXXX;
}

int ret_from_fork(TBIRES arg)
{
	struct task_struct *prev = arg.Switch.pPara;
	struct task_struct *tsk = current;
	struct pt_regs *regs = task_pt_regs(tsk);
	int (*fn)(void *);
	TBIRES Next;

	schedule_tail(prev);

	if (tsk->flags & PF_KTHREAD) {
		fn = (void *)regs->ctx.DX[4].U1;
		BUG_ON(!fn);

		fn((void *)regs->ctx.DX[3].U1);
	}

	if (test_syscall_work())
		syscall_trace_leave(regs);

	preempt_disable();

	Next.Sig.TrigMask = get_trigger_mask();
	Next.Sig.SaveMask = 0;
	Next.Sig.pCtx = &regs->ctx;

	set_gateway_tls(current->thread.tls_ptr);

	preempt_enable_no_resched();

	/* And interrupts should come back on when we resume the real usermode
	 * code. Call __TBIASyncResume()
	 */
	__TBIASyncResume(tail_end(Next));
	/* ASyncResume should NEVER return */
	BUG();
	return 0;
}

void show_trace(struct task_struct *tsk, unsigned long *sp,
		struct pt_regs *regs)
{
	unsigned long addr;
#ifdef CONFIG_FRAME_POINTER
	unsigned long fp, fpnew;
	unsigned long stack;
#endif

	if (regs && user_mode(regs))
		return;

	printk("\nCall trace: ");
#ifdef CONFIG_KALLSYMS
	printk("\n");
#endif

	if (!tsk)
		tsk = current;

#ifdef CONFIG_FRAME_POINTER
	if (regs) {
		print_ip_sym(regs->ctx.CurrPC);
		fp = regs->ctx.AX[1].U0;
	} else {
		fp = __core_reg_get(A0FrP);
	}

	/* detect when the frame pointer has been used for other purposes and
	 * doesn't point to the stack (it may point completely elsewhere which
	 * kstack_end may not detect).
	 */
	stack = (unsigned long)task_stack_page(tsk);
	while (fp >= stack && fp + 8 <= stack + THREAD_SIZE) {
		addr = __raw_readl((unsigned long *)(fp + 4)) - 4;
		if (kernel_text_address(addr))
			print_ip_sym(addr);
		else
			break;
		/* stack grows up, so frame pointers must decrease */
		fpnew = __raw_readl((unsigned long *)(fp + 0));
		if (fpnew >= fp)
			break;
		fp = fpnew;
	}
#else
	while (!kstack_end(sp)) {
		addr = (*sp--) - 4;
		if (kernel_text_address(addr))
			print_ip_sym(addr);
	}
#endif

	printk("\n");

	debug_show_held_locks(tsk);
}

void show_stack(struct task_struct *tsk, unsigned long *sp)
{
	if (!tsk)
		tsk = current;
	if (tsk == current)
		sp = (unsigned long *)current_stack_pointer;
	else
		sp = (unsigned long *)tsk->thread.kernel_context->AX[0].U0;

	show_trace(tsk, sp, NULL);
}

void dump_stack(void)
{
	show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);