[mirror_ubuntu-artful-kernel.git] / arch / hexagon / kernel / traps.c

/*
 * Kernel traps/events for Hexagon processor
 *
 * Copyright (c) 2010-2014, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/init.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/kdebug.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/tracehook.h>
#include <asm/traps.h>
#include <asm/vm_fault.h>
#include <asm/syscall.h>
#include <asm/registers.h>
#include <asm/unistd.h>
#include <asm/sections.h>
#ifdef CONFIG_KGDB
# include <linux/kgdb.h>
#endif

#define TRAP_SYSCALL	1
#define TRAP_DEBUG	0xdb

void __init trap_init(void)
{
}

#ifdef CONFIG_GENERIC_BUG
/* Maybe should resemble arch/sh/kernel/traps.c ?? */
int is_valid_bugaddr(unsigned long addr)
{
	return 1;
}
#endif /* CONFIG_GENERIC_BUG */

static const char *ex_name(int ex)
{
	switch (ex) {
	case HVM_GE_C_XPROT:
	case HVM_GE_C_XUSER:
		return "Execute protection fault";
	case HVM_GE_C_RPROT:
	case HVM_GE_C_RUSER:
		return "Read protection fault";
	case HVM_GE_C_WPROT:
	case HVM_GE_C_WUSER:
		return "Write protection fault";
	case HVM_GE_C_XMAL:
		return "Misaligned instruction";
	case HVM_GE_C_WREG:
		return "Multiple writes to same register in packet";
	case HVM_GE_C_PCAL:
		return "Program counter values that are not properly aligned";
	case HVM_GE_C_RMAL:
		return "Misaligned data load";
	case HVM_GE_C_WMAL:
		return "Misaligned data store";
	case HVM_GE_C_INVI:
	case HVM_GE_C_PRIVI:
		return "Illegal instruction";
	case HVM_GE_C_BUS:
		return "Precise bus error";
	case HVM_GE_C_CACHE:
		return "Cache error";

	case 0xdb:
		return "Debugger trap";

	default:
		return "Unrecognized exception";
	}
}

static void do_show_stack(struct task_struct *task, unsigned long *fp,
			  unsigned long ip)
{
	int kstack_depth_to_print = 24;
	unsigned long offset, size;
	const char *name = NULL;
	unsigned long *newfp;
	unsigned long low, high;
	char tmpstr[128];
	char *modname;
	int i;

	if (task == NULL)
		task = current;

	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
	       raw_smp_processor_id(), task->comm,
	       task_pid_nr(task));

	if (fp == NULL) {
		if (task == current) {
			asm("%0 = r30" : "=r" (fp));
		} else {
			fp = (unsigned long *)
			     ((struct hexagon_switch_stack *)
			     task->thread.switch_sp)->fp;
		}
	}

	if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
		printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
		return;
	}

	/* Saved link reg is one word above FP */
	if (!ip)
		ip = *(fp+1);

	/* Expect kernel stack to be in-bounds */
	low = (unsigned long)task_stack_page(task);
	high = low + THREAD_SIZE - 8;
	low += sizeof(struct thread_info);

	for (i = 0; i < kstack_depth_to_print; i++) {

		name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);

		printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
			offset);
		if (((unsigned long) fp < low) || (high < (unsigned long) fp))
			printk(KERN_CONT " (FP out of bounds!)");
		if (modname)
			printk(KERN_CONT " [%s] ", modname);
		printk(KERN_CONT "\n");

		newfp = (unsigned long *) *fp;

		if (((unsigned long) newfp) & 0x3) {
			printk(KERN_INFO "-- Corrupt frame pointer %p\n",
				newfp);
			break;
		}

		/* Attempt to continue past exception. */
		if (0 == newfp) {
			struct pt_regs *regs = (struct pt_regs *) (((void *)fp)
						+ 8);

			if (regs->syscall_nr != -1) {
				printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
					regs->syscall_nr);
				printk(KERN_CONT "  psp: %lx  elr: %lx\n",
					 pt_psp(regs), pt_elr(regs));
				break;
			} else {
				/* really want to see more ... */
				kstack_depth_to_print += 6;
				printk(KERN_INFO "-- %s (0x%lx)  badva: %lx\n",
					ex_name(pt_cause(regs)), pt_cause(regs),
					pt_badva(regs));
			}

			newfp = (unsigned long *) regs->r30;
			ip = pt_elr(regs);
		} else {
			ip = *(newfp + 1);
		}

		/* If link reg is null, we are done. */
		if (ip == 0x0)
			break;

		/* If newfp isn't larger, we're tracing garbage. */
		if (newfp > fp)
			fp = newfp;
		else
			break;
	}
}

void show_stack(struct task_struct *task, unsigned long *fp)
{
	/* Saved link reg is one word above FP */
	do_show_stack(task, fp, 0);
}

int die(const char *str, struct pt_regs *regs, long err)
{
	static struct {
		spinlock_t lock;
		int counter;
	} die = {
		.lock = __SPIN_LOCK_UNLOCKED(die.lock),
		.counter = 0
	};

	console_verbose();
	oops_enter();

	spin_lock_irq(&die.lock);
	bust_spinlocks(1);
	printk(KERN_EMERG "Oops: %s[#%d]:\n", str, ++die.counter);

	if (notify_die(DIE_OOPS, str, regs, err, pt_cause(regs), SIGSEGV) ==
	    NOTIFY_STOP)
		return 1;

	print_modules();
	show_regs(regs);
	do_show_stack(current, &regs->r30, pt_elr(regs));

	bust_spinlocks(0);
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);

	spin_unlock_irq(&die.lock);

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

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

	oops_exit();
	do_exit(err);
	return 0;
}

int die_if_kernel(char *str, struct pt_regs *regs, long err)
{
	if (!user_mode(regs))
		return die(str, regs, err);
	else
		return 0;
}

/*
 * It's not clear that misaligned fetches are ever recoverable.
 */
static void misaligned_instruction(struct pt_regs *regs)
{
	die_if_kernel("Misaligned Instruction", regs, 0);
	force_sig(SIGBUS, current);
}

/*
 * Misaligned loads and stores, on the other hand, can be
 * emulated, and probably should be, some day.  But for now
 * they will be considered fatal.
 */
static void misaligned_data_load(struct pt_regs *regs)
{
	die_if_kernel("Misaligned Data Load", regs, 0);
	force_sig(SIGBUS, current);
}

static void misaligned_data_store(struct pt_regs *regs)
{
	die_if_kernel("Misaligned Data Store", regs, 0);
	force_sig(SIGBUS, current);
}

static void illegal_instruction(struct pt_regs *regs)
{
	die_if_kernel("Illegal Instruction", regs, 0);
	force_sig(SIGILL, current);
}

/*
 * Precise bus errors may be recoverable with a a retry,
 * but for now, treat them as irrecoverable.
 */
static void precise_bus_error(struct pt_regs *regs)
{
	die_if_kernel("Precise Bus Error", regs, 0);
	force_sig(SIGBUS, current);
}

/*
 * If anything is to be done here other than panic,
 * it will probably be complex and migrate to another
 * source module.  For now, just die.
 */
static void cache_error(struct pt_regs *regs)
{
	die("Cache Error", regs, 0);
}

/*
 * General exception handler
 */
void do_genex(struct pt_regs *regs)
{
	/*
	 * Decode Cause and Dispatch
	 */
	switch (pt_cause(regs)) {
	case HVM_GE_C_XPROT:
	case HVM_GE_C_XUSER:
		execute_protection_fault(regs);
		break;
	case HVM_GE_C_RPROT:
	case HVM_GE_C_RUSER:
		read_protection_fault(regs);
		break;
	case HVM_GE_C_WPROT:
	case HVM_GE_C_WUSER:
		write_protection_fault(regs);
		break;
	case HVM_GE_C_XMAL:
		misaligned_instruction(regs);
		break;
	case HVM_GE_C_WREG:
		illegal_instruction(regs);
		break;
	case HVM_GE_C_PCAL:
		misaligned_instruction(regs);
		break;
	case HVM_GE_C_RMAL:
		misaligned_data_load(regs);
		break;
	case HVM_GE_C_WMAL:
		misaligned_data_store(regs);
		break;
	case HVM_GE_C_INVI:
	case HVM_GE_C_PRIVI:
		illegal_instruction(regs);
		break;
	case HVM_GE_C_BUS:
		precise_bus_error(regs);
		break;
	case HVM_GE_C_CACHE:
		cache_error(regs);
		break;
	default:
		/* Halt and catch fire */
		panic("Unrecognized exception 0x%lx\n", pt_cause(regs));
		break;
	}
}

/* Indirect system call dispatch */
long sys_syscall(void)
{
	printk(KERN_ERR "sys_syscall invoked!\n");
	return -ENOSYS;
}

void do_trap0(struct pt_regs *regs)
{
	syscall_fn syscall;

	switch (pt_cause(regs)) {
	case TRAP_SYSCALL:
		/* System call is trap0 #1 */

		/* allow strace to catch syscall args  */
		if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE) &&
			tracehook_report_syscall_entry(regs)))
			return;  /*  return -ENOSYS somewhere?  */

		/* Interrupts should be re-enabled for syscall processing */
		__vmsetie(VM_INT_ENABLE);

		/*
		 * System call number is in r6, arguments in r0..r5.
		 * Fortunately, no Linux syscall has more than 6 arguments,
		 * and Hexagon ABI passes first 6 arguments in registers.
		 * 64-bit arguments are passed in odd/even register pairs.
		 * Fortunately, we have no system calls that take more
		 * than three arguments with more than one 64-bit value.
		 * Should that change, we'd need to redesign to copy
		 * between user and kernel stacks.
		 */
		regs->syscall_nr = regs->r06;

		/*
		 * GPR R0 carries the first parameter, and is also used
		 * to report the return value.  We need a backup of
		 * the user's value in case we need to do a late restart
		 * of the system call.
		 */
		regs->restart_r0 = regs->r00;

		if ((unsigned long) regs->syscall_nr >= __NR_syscalls) {
			regs->r00 = -1;
		} else {
			syscall = (syscall_fn)
				  (sys_call_table[regs->syscall_nr]);
			regs->r00 = syscall(regs->r00, regs->r01,
				   regs->r02, regs->r03,
				   regs->r04, regs->r05);
		}

		/* allow strace to get the syscall return state  */
		if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE)))
			tracehook_report_syscall_exit(regs, 0);

		break;
	case TRAP_DEBUG:
		/* Trap0 0xdb is debug breakpoint */
		if (user_mode(regs)) {
			struct siginfo info;

			info.si_signo = SIGTRAP;
			info.si_errno = 0;
			/*
			 * Some architecures add some per-thread state
			 * to distinguish between breakpoint traps and
			 * trace traps.  We may want to do that, and
			 * set the si_code value appropriately, or we
			 * may want to use a different trap0 flavor.
			 */
			info.si_code = TRAP_BRKPT;
			info.si_addr = (void __user *) pt_elr(regs);
			force_sig_info(SIGTRAP, &info, current);
		} else {
#ifdef CONFIG_KGDB
			kgdb_handle_exception(pt_cause(regs), SIGTRAP,
					      TRAP_BRKPT, regs);
#endif
		}
		break;
	}
	/* Ignore other trap0 codes for now, especially 0 (Angel calls) */
}

/*
 * Machine check exception handler
 */
void do_machcheck(struct pt_regs *regs)
{
	/* Halt and catch fire */
	__vmstop();
}

/*
 * Treat this like the old 0xdb trap.
 */

void do_debug_exception(struct pt_regs *regs)
{
	regs->hvmer.vmest &= ~HVM_VMEST_CAUSE_MSK;
	regs->hvmer.vmest |= (TRAP_DEBUG << HVM_VMEST_CAUSE_SFT);
	do_trap0(regs);
}
Commit	Line	Data
cf9750ba RK	1	/*
	2	* Kernel traps/events for Hexagon processor
	3	*
8914d7e8	4	* Copyright (c) 2010-2014, The Linux Foundation. All rights reserved.
cf9750ba RK	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 and
	8	* only version 2 as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	18	* 02110-1301, USA.
	19	*/
	20
	21	#include <linux/init.h>
3f07c014	22	#include <linux/sched/signal.h>
b17b0153	23	#include <linux/sched/debug.h>
cf9750ba RK	24	#include <linux/module.h>
	25	#include <linux/kallsyms.h>
	26	#include <linux/kdebug.h>
	27	#include <linux/syscalls.h>
	28	#include <linux/signal.h>
	29	#include <linux/tracehook.h>
	30	#include <asm/traps.h>
	31	#include <asm/vm_fault.h>
	32	#include <asm/syscall.h>
	33	#include <asm/registers.h>
	34	#include <asm/unistd.h>
	35	#include <asm/sections.h>
	36	#ifdef CONFIG_KGDB
	37	# include <linux/kgdb.h>
	38	#endif
	39
	40	#define TRAP_SYSCALL 1
	41	#define TRAP_DEBUG 0xdb
	42
	43	void __init trap_init(void)
	44	{
	45	}
	46
	47	#ifdef CONFIG_GENERIC_BUG
	48	/* Maybe should resemble arch/sh/kernel/traps.c ?? */
	49	int is_valid_bugaddr(unsigned long addr)
	50	{
	51	return 1;
	52	}
	53	#endif /* CONFIG_GENERIC_BUG */
	54
	55	static const char *ex_name(int ex)
	56	{
	57	switch (ex) {
	58	case HVM_GE_C_XPROT:
	59	case HVM_GE_C_XUSER:
	60	return "Execute protection fault";
	61	case HVM_GE_C_RPROT:
	62	case HVM_GE_C_RUSER:
	63	return "Read protection fault";
	64	case HVM_GE_C_WPROT:
	65	case HVM_GE_C_WUSER:
	66	return "Write protection fault";
	67	case HVM_GE_C_XMAL:
	68	return "Misaligned instruction";
db0fe532 RK	69	case HVM_GE_C_WREG:
	70	return "Multiple writes to same register in packet";
	71	case HVM_GE_C_PCAL:
	72	return "Program counter values that are not properly aligned";
cf9750ba RK	73	case HVM_GE_C_RMAL:
	74	return "Misaligned data load";
	75	case HVM_GE_C_WMAL:
	76	return "Misaligned data store";
	77	case HVM_GE_C_INVI:
	78	case HVM_GE_C_PRIVI:
	79	return "Illegal instruction";
	80	case HVM_GE_C_BUS:
	81	return "Precise bus error";
	82	case HVM_GE_C_CACHE:
	83	return "Cache error";
	84
	85	case 0xdb:
	86	return "Debugger trap";
	87
	88	default:
	89	return "Unrecognized exception";
	90	}
	91	}
	92
	93	static void do_show_stack(struct task_struct task, unsigned long fp,
	94	unsigned long ip)
	95	{
	96	int kstack_depth_to_print = 24;
	97	unsigned long offset, size;
	98	const char *name = NULL;
	99	unsigned long *newfp;
	100	unsigned long low, high;
	101	char tmpstr[128];
	102	char *modname;
	103	int i;
	104
	105	if (task == NULL)
	106	task = current;
	107
	108	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
	109	raw_smp_processor_id(), task->comm,
	110	task_pid_nr(task));
	111
	112	if (fp == NULL) {
	113	if (task == current) {
	114	asm("%0 = r30" : "=r" (fp));
	115	} else {
	116	fp = (unsigned long *)
	117	((struct hexagon_switch_stack *)
	118	task->thread.switch_sp)->fp;
	119	}
	120	}
	121
	122	if ((((unsigned long) fp) & 0x3) \|\| ((unsigned long) fp < 0x1000)) {
	123	printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
	124	return;
	125	}
	126
	127	/* Saved link reg is one word above FP */
	128	if (!ip)
	129	ip = *(fp+1);
	130
	131	/* Expect kernel stack to be in-bounds */
	132	low = (unsigned long)task_stack_page(task);
	133	high = low + THREAD_SIZE - 8;
	134	low += sizeof(struct thread_info);
	135
	136	for (i = 0; i < kstack_depth_to_print; i++) {
137
138	name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);
139
140	printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
141	offset);
142	if (((unsigned long) fp < low) \|\| (high < (unsigned long) fp))
143	printk(KERN_CONT " (FP out of bounds!)");
144	if (modname)
145	printk(KERN_CONT " [%s] ", modname);
146	printk(KERN_CONT "\n");
147
148	newfp = (unsigned long ) fp;
149
150	if (((unsigned long) newfp) & 0x3) {
151	printk(KERN_INFO "-- Corrupt frame pointer %p\n",
152	newfp);
153	break;
154	}
155
156	/* Attempt to continue past exception. */
157	if (0 == newfp) {
158	struct pt_regs regs = (struct pt_regs ) (((void *)fp)
159	+ 8);
160
161	if (regs->syscall_nr != -1) {
162	printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
163	regs->syscall_nr);
164	printk(KERN_CONT " psp: %lx elr: %lx\n",
165	pt_psp(regs), pt_elr(regs));
166	break;
167	} else {
168	/* really want to see more ... */
169	kstack_depth_to_print += 6;
170	printk(KERN_INFO "-- %s (0x%lx) badva: %lx\n",
171	ex_name(pt_cause(regs)), pt_cause(regs),
172	pt_badva(regs));
173	}
174
175	newfp = (unsigned long *) regs->r30;
176	ip = pt_elr(regs);
177	} else {
178	ip = *(newfp + 1);
179	}
180
181	/* If link reg is null, we are done. */
182	if (ip == 0x0)
183	break;
184
185	/* If newfp isn't larger, we're tracing garbage. */
186	if (newfp > fp)
187	fp = newfp;
188	else
189	break;
190	}
191	}
192
193	void show_stack(struct task_struct task, unsigned long fp)
194	{
195	/* Saved link reg is one word above FP */
196	do_show_stack(task, fp, 0);
197	}
198
cf9750ba RK	199	int die(const char str, struct pt_regs regs, long err)
	200	{
	201	static struct {
	202	spinlock_t lock;
	203	int counter;
	204	} die = {
	205	.lock = __SPIN_LOCK_UNLOCKED(die.lock),
	206	.counter = 0
	207	};
	208
	209	console_verbose();
	210	oops_enter();
	211
	212	spin_lock_irq(&die.lock);
	213	bust_spinlocks(1);
	214	printk(KERN_EMERG "Oops: %s[#%d]:\n", str, ++die.counter);
	215
	216	if (notify_die(DIE_OOPS, str, regs, err, pt_cause(regs), SIGSEGV) ==
	217	NOTIFY_STOP)
	218	return 1;
	219
	220	print_modules();
	221	show_regs(regs);
	222	do_show_stack(current, &regs->r30, pt_elr(regs));
	223
	224	bust_spinlocks(0);
373d4d09	225	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
cf9750ba RK	226
	227	spin_unlock_irq(&die.lock);
	228
	229	if (in_interrupt())
	230	panic("Fatal exception in interrupt");
	231
	232	if (panic_on_oops)
	233	panic("Fatal exception");
	234
	235	oops_exit();
	236	do_exit(err);
	237	return 0;
	238	}
	239
	240	int die_if_kernel(char str, struct pt_regs regs, long err)
	241	{
	242	if (!user_mode(regs))
	243	return die(str, regs, err);
	244	else
	245	return 0;
	246	}
	247
	248	/*
	249	* It's not clear that misaligned fetches are ever recoverable.
	250	*/
	251	static void misaligned_instruction(struct pt_regs *regs)
	252	{
	253	die_if_kernel("Misaligned Instruction", regs, 0);
	254	force_sig(SIGBUS, current);
	255	}
	256
	257	/*
	258	* Misaligned loads and stores, on the other hand, can be
	259	* emulated, and probably should be, some day. But for now
	260	* they will be considered fatal.
	261	*/
	262	static void misaligned_data_load(struct pt_regs *regs)
	263	{
	264	die_if_kernel("Misaligned Data Load", regs, 0);
	265	force_sig(SIGBUS, current);
	266	}
	267
	268	static void misaligned_data_store(struct pt_regs *regs)
	269	{
	270	die_if_kernel("Misaligned Data Store", regs, 0);
	271	force_sig(SIGBUS, current);
	272	}
	273
	274	static void illegal_instruction(struct pt_regs *regs)
	275	{
	276	die_if_kernel("Illegal Instruction", regs, 0);
	277	force_sig(SIGILL, current);
	278	}
	279
	280	/*
	281	* Precise bus errors may be recoverable with a a retry,
	282	* but for now, treat them as irrecoverable.
	283	*/
	284	static void precise_bus_error(struct pt_regs *regs)
	285	{
	286	die_if_kernel("Precise Bus Error", regs, 0);
	287	force_sig(SIGBUS, current);
	288	}
	289
290	/*
291	* If anything is to be done here other than panic,
292	* it will probably be complex and migrate to another
293	* source module. For now, just die.
294	*/
295	static void cache_error(struct pt_regs *regs)
296	{
297	die("Cache Error", regs, 0);
298	}
299
300	/*
301	* General exception handler
302	*/
303	void do_genex(struct pt_regs *regs)
304	{
305	/*
306	* Decode Cause and Dispatch
307	*/
308	switch (pt_cause(regs)) {
309	case HVM_GE_C_XPROT:
310	case HVM_GE_C_XUSER:
311	execute_protection_fault(regs);
312	break;
313	case HVM_GE_C_RPROT:
314	case HVM_GE_C_RUSER:
315	read_protection_fault(regs);
316	break;
317	case HVM_GE_C_WPROT:
318	case HVM_GE_C_WUSER:
319	write_protection_fault(regs);
320	break;
321	case HVM_GE_C_XMAL:
322	misaligned_instruction(regs);
323	break;
db0fe532 RK	324	case HVM_GE_C_WREG:
	325	illegal_instruction(regs);
	326	break;
	327	case HVM_GE_C_PCAL:
	328	misaligned_instruction(regs);
	329	break;
cf9750ba RK	330	case HVM_GE_C_RMAL:
	331	misaligned_data_load(regs);
	332	break;
	333	case HVM_GE_C_WMAL:
	334	misaligned_data_store(regs);
	335	break;
	336	case HVM_GE_C_INVI:
	337	case HVM_GE_C_PRIVI:
	338	illegal_instruction(regs);
	339	break;
	340	case HVM_GE_C_BUS:
	341	precise_bus_error(regs);
	342	break;
	343	case HVM_GE_C_CACHE:
	344	cache_error(regs);
	345	break;
	346	default:
	347	/* Halt and catch fire */
	348	panic("Unrecognized exception 0x%lx\n", pt_cause(regs));
	349	break;
	350	}
	351	}
	352
	353	/* Indirect system call dispatch */
	354	long sys_syscall(void)
	355	{
	356	printk(KERN_ERR "sys_syscall invoked!\n");
	357	return -ENOSYS;
	358	}
	359
	360	void do_trap0(struct pt_regs *regs)
	361	{
cf9750ba RK	362	syscall_fn syscall;
	363
	364	switch (pt_cause(regs)) {
	365	case TRAP_SYSCALL:
	366	/* System call is trap0 #1 */
	367
	368	/* allow strace to catch syscall args */
	369	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE) &&
	370	tracehook_report_syscall_entry(regs)))
	371	return; /* return -ENOSYS somewhere? */
	372
	373	/* Interrupts should be re-enabled for syscall processing */
	374	__vmsetie(VM_INT_ENABLE);
	375
	376	/*
	377	* System call number is in r6, arguments in r0..r5.
	378	* Fortunately, no Linux syscall has more than 6 arguments,
	379	* and Hexagon ABI passes first 6 arguments in registers.
	380	* 64-bit arguments are passed in odd/even register pairs.
	381	* Fortunately, we have no system calls that take more
	382	* than three arguments with more than one 64-bit value.
	383	* Should that change, we'd need to redesign to copy
	384	* between user and kernel stacks.
	385	*/
	386	regs->syscall_nr = regs->r06;
	387
	388	/*
	389	* GPR R0 carries the first parameter, and is also used
	390	* to report the return value. We need a backup of
	391	* the user's value in case we need to do a late restart
	392	* of the system call.
	393	*/
	394	regs->restart_r0 = regs->r00;
	395
	396	if ((unsigned long) regs->syscall_nr >= __NR_syscalls) {
	397	regs->r00 = -1;
	398	} else {
	399	syscall = (syscall_fn)
	400	(sys_call_table[regs->syscall_nr]);
a11e67c2	401	regs->r00 = syscall(regs->r00, regs->r01,
cf9750ba RK	402	regs->r02, regs->r03,
	403	regs->r04, regs->r05);
	404	}
	405
cf9750ba RK	406	/* allow strace to get the syscall return state */
	407	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE)))
	408	tracehook_report_syscall_exit(regs, 0);
	409
	410	break;
	411	case TRAP_DEBUG:
	412	/* Trap0 0xdb is debug breakpoint */
	413	if (user_mode(regs)) {
	414	struct siginfo info;
	415
	416	info.si_signo = SIGTRAP;
	417	info.si_errno = 0;
	418	/*
	419	* Some architecures add some per-thread state
	420	* to distinguish between breakpoint traps and
	421	* trace traps. We may want to do that, and
	422	* set the si_code value appropriately, or we
	423	* may want to use a different trap0 flavor.
	424	*/
	425	info.si_code = TRAP_BRKPT;
	426	info.si_addr = (void __user *) pt_elr(regs);
8914d7e8	427	force_sig_info(SIGTRAP, &info, current);
cf9750ba RK	428	} else {
	429	#ifdef CONFIG_KGDB
	430	kgdb_handle_exception(pt_cause(regs), SIGTRAP,
	431	TRAP_BRKPT, regs);
	432	#endif
	433	}
	434	break;
	435	}
	436	/* Ignore other trap0 codes for now, especially 0 (Angel calls) */
	437	}
	438
	439	/*
	440	* Machine check exception handler
	441	*/
	442	void do_machcheck(struct pt_regs *regs)
	443	{
	444	/* Halt and catch fire */
	445	__vmstop();
	446	}
7777746c RK	447
	448	/*
	449	* Treat this like the old 0xdb trap.
	450	*/
	451
	452	void do_debug_exception(struct pt_regs *regs)
	453	{
	454	regs->hvmer.vmest &= ~HVM_VMEST_CAUSE_MSK;
	455	regs->hvmer.vmest \|= (TRAP_DEBUG << HVM_VMEST_CAUSE_SFT);
	456	do_trap0(regs);
	457	}