[mirror_ubuntu-bionic-kernel.git] / arch / um / kernel / trap.c

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/hardirq.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/sched/debug.h>
#include <asm/current.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <arch.h>
#include <as-layout.h>
#include <kern_util.h>
#include <os.h>
#include <skas.h>

/*
 * Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
 * segv().
 */
int handle_page_fault(unsigned long address, unsigned long ip,
		      int is_write, int is_user, int *code_out)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	int err = -EFAULT;
	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;

	*code_out = SEGV_MAPERR;

	/*
	 * If the fault was with pagefaults disabled, don't take the fault, just
	 * fail.
	 */
	if (faulthandler_disabled())
		goto out_nosemaphore;

	if (is_user)
		flags |= FAULT_FLAG_USER;
retry:
	down_read(&mm->mmap_sem);
	vma = find_vma(mm, address);
	if (!vma)
		goto out;
	else if (vma->vm_start <= address)
		goto good_area;
	else if (!(vma->vm_flags & VM_GROWSDOWN))
		goto out;
	else if (is_user && !ARCH_IS_STACKGROW(address))
		goto out;
	else if (expand_stack(vma, address))
		goto out;

good_area:
	*code_out = SEGV_ACCERR;
	if (is_write) {
		if (!(vma->vm_flags & VM_WRITE))
			goto out;
		flags |= FAULT_FLAG_WRITE;
	} else {
		/* Don't require VM_READ|VM_EXEC for write faults! */
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto out;
	}

	do {
		int fault;

		fault = handle_mm_fault(vma, address, flags);

		if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
			goto out_nosemaphore;

		if (unlikely(fault & VM_FAULT_ERROR)) {
			if (fault & VM_FAULT_OOM) {
				goto out_of_memory;
			} else if (fault & VM_FAULT_SIGSEGV) {
				goto out;
			} else if (fault & VM_FAULT_SIGBUS) {
				err = -EACCES;
				goto out;
			}
			BUG();
		}
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
			if (fault & VM_FAULT_MAJOR)
				current->maj_flt++;
			else
				current->min_flt++;
			if (fault & VM_FAULT_RETRY) {
				flags &= ~FAULT_FLAG_ALLOW_RETRY;
				flags |= FAULT_FLAG_TRIED;

				goto retry;
			}
		}

		pgd = pgd_offset(mm, address);
		pud = pud_offset(pgd, address);
		pmd = pmd_offset(pud, address);
		pte = pte_offset_kernel(pmd, address);
	} while (!pte_present(*pte));
	err = 0;
	/*
	 * The below warning was added in place of
	 *	pte_mkyoung(); if (is_write) pte_mkdirty();
	 * If it's triggered, we'd see normally a hang here (a clean pte is
	 * marked read-only to emulate the dirty bit).
	 * However, the generic code can mark a PTE writable but clean on a
	 * concurrent read fault, triggering this harmlessly. So comment it out.
	 */
#if 0
	WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte)));
#endif
	flush_tlb_page(vma, address);
out:
	up_read(&mm->mmap_sem);
out_nosemaphore:
	return err;

out_of_memory:
	/*
	 * We ran out of memory, call the OOM killer, and return the userspace
	 * (which will retry the fault, or kill us if we got oom-killed).
	 */
	up_read(&mm->mmap_sem);
	if (!is_user)
		goto out_nosemaphore;
	pagefault_out_of_memory();
	return 0;
}
EXPORT_SYMBOL(handle_page_fault);

static void show_segv_info(struct uml_pt_regs *regs)
{
	struct task_struct *tsk = current;
	struct faultinfo *fi = UPT_FAULTINFO(regs);

	if (!unhandled_signal(tsk, SIGSEGV))
		return;

	if (!printk_ratelimit())
		return;

	printk("%s%s[%d]: segfault at %lx ip %px sp %px error %x",
		task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
		tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
		(void *)UPT_IP(regs), (void *)UPT_SP(regs),
		fi->error_code);

	print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
	printk(KERN_CONT "\n");
}

static void bad_segv(struct faultinfo fi, unsigned long ip)
{
	struct siginfo si;

	si.si_signo = SIGSEGV;
	si.si_code = SEGV_ACCERR;
	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
	current->thread.arch.faultinfo = fi;
	force_sig_info(SIGSEGV, &si, current);
}

void fatal_sigsegv(void)
{
	force_sigsegv(SIGSEGV, current);
	do_signal(&current->thread.regs);
	/*
	 * This is to tell gcc that we're not returning - do_signal
	 * can, in general, return, but in this case, it's not, since
	 * we just got a fatal SIGSEGV queued.
	 */
	os_dump_core();
}

/**
 * segv_handler() - the SIGSEGV handler
 * @sig:	the signal number
 * @unused_si:	the signal info struct; unused in this handler
 * @regs:	the ptrace register information
 *
 * The handler first extracts the faultinfo from the UML ptrace regs struct.
 * If the userfault did not happen in an UML userspace process, bad_segv is called.
 * Otherwise the signal did happen in a cloned userspace process, handle it.
 */
void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
{
	struct faultinfo * fi = UPT_FAULTINFO(regs);

	if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
		show_segv_info(regs);
		bad_segv(*fi, UPT_IP(regs));
		return;
	}
	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
}

/*
 * We give a *copy* of the faultinfo in the regs to segv.
 * This must be done, since nesting SEGVs could overwrite
 * the info in the regs. A pointer to the info then would
 * give us bad data!
 */
unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
		   struct uml_pt_regs *regs)
{
	struct siginfo si;
	jmp_buf *catcher;
	int err;
	int is_write = FAULT_WRITE(fi);
	unsigned long address = FAULT_ADDRESS(fi);

	if (!is_user && regs)
		current->thread.segv_regs = container_of(regs, struct pt_regs, regs);

	if (!is_user && (address >= start_vm) && (address < end_vm)) {
		flush_tlb_kernel_vm();
		goto out;
	}
	else if (current->mm == NULL) {
		show_regs(container_of(regs, struct pt_regs, regs));
		panic("Segfault with no mm");
	}
	else if (!is_user && address > PAGE_SIZE && address < TASK_SIZE) {
		show_regs(container_of(regs, struct pt_regs, regs));
		panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx",
		       address, ip);
	}

	if (SEGV_IS_FIXABLE(&fi))
		err = handle_page_fault(address, ip, is_write, is_user,
					&si.si_code);
	else {
		err = -EFAULT;
		/*
		 * A thread accessed NULL, we get a fault, but CR2 is invalid.
		 * This code is used in __do_copy_from_user() of TT mode.
		 * XXX tt mode is gone, so maybe this isn't needed any more
		 */
		address = 0;
	}

	catcher = current->thread.fault_catcher;
	if (!err)
		goto out;
	else if (catcher != NULL) {
		current->thread.fault_addr = (void *) address;
		UML_LONGJMP(catcher, 1);
	}
	else if (current->thread.fault_addr != NULL)
		panic("fault_addr set but no fault catcher");
	else if (!is_user && arch_fixup(ip, regs))
		goto out;

	if (!is_user) {
		show_regs(container_of(regs, struct pt_regs, regs));
		panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
		      address, ip);
	}

	show_segv_info(regs);

	if (err == -EACCES) {
		si.si_signo = SIGBUS;
		si.si_errno = 0;
		si.si_code = BUS_ADRERR;
		si.si_addr = (void __user *)address;
		current->thread.arch.faultinfo = fi;
		force_sig_info(SIGBUS, &si, current);
	} else {
		BUG_ON(err != -EFAULT);
		si.si_signo = SIGSEGV;
		si.si_addr = (void __user *) address;
		current->thread.arch.faultinfo = fi;
		force_sig_info(SIGSEGV, &si, current);
	}

out:
	if (regs)
		current->thread.segv_regs = NULL;

	return 0;
}

void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
	struct faultinfo *fi;
	struct siginfo clean_si;

	if (!UPT_IS_USER(regs)) {
		if (sig == SIGBUS)
			printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
			       "mount likely just ran out of space\n");
		panic("Kernel mode signal %d", sig);
	}

	arch_examine_signal(sig, regs);

	memset(&clean_si, 0, sizeof(clean_si));
	clean_si.si_signo = si->si_signo;
	clean_si.si_errno = si->si_errno;
	clean_si.si_code = si->si_code;
	switch (sig) {
	case SIGILL:
	case SIGFPE:
	case SIGSEGV:
	case SIGBUS:
	case SIGTRAP:
		fi = UPT_FAULTINFO(regs);
		clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
		current->thread.arch.faultinfo = *fi;
#ifdef __ARCH_SI_TRAPNO
		clean_si.si_trapno = si->si_trapno;
#endif
		break;
	default:
		printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
			sig, si->si_code);
	}

	force_sig_info(sig, &clean_si, current);
}

void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
	if (current->thread.fault_catcher != NULL)
		UML_LONGJMP(current->thread.fault_catcher, 1);
	else
		relay_signal(sig, si, regs);
}

void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
{
	do_IRQ(WINCH_IRQ, regs);
}

void trap_init(void)
{
}
Commit	Line	Data
ea2ba7dc	1	/*
4c9e1385	2	* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
1da177e4 LT	3	* Licensed under the GPL
	4	*/
	5
4c9e1385	6	#include <linux/mm.h>
3f07c014	7	#include <linux/sched/signal.h>
4c9e1385	8	#include <linux/hardirq.h>
73395a00	9	#include <linux/module.h>
fbc9f16a	10	#include <linux/uaccess.h>
b17b0153	11	#include <linux/sched/debug.h>
4c9e1385 JD	12	#include <asm/current.h>
	13	#include <asm/pgtable.h>
	14	#include <asm/tlbflush.h>
37185b33 AV	15	#include <arch.h>
	16	#include <as-layout.h>
	17	#include <kern_util.h>
	18	#include <os.h>
	19	#include <skas.h>
1da177e4	20
4c9e1385 JD	21	/*
	22	* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
	23	* segv().
	24	*/
1d3468a6	25	int handle_page_fault(unsigned long address, unsigned long ip,
1da177e4 LT	26	int is_write, int is_user, int *code_out)
	27	{
	28	struct mm_struct *mm = current->mm;
	29	struct vm_area_struct *vma;
	30	pgd_t *pgd;
	31	pud_t *pud;
	32	pmd_t *pmd;
	33	pte_t *pte;
1da177e4	34	int err = -EFAULT;
759496ba	35	unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
1da177e4 LT	36
1da177e4 LT	37	*code_out = SEGV_MAPERR;
fea03cb4	38
4c9e1385	39	/*
70ffdb93	40	* If the fault was with pagefaults disabled, don't take the fault, just
4c9e1385 JD	41	* fail.
4c9e1385 JD	42	*/
70ffdb93	43	if (faulthandler_disabled())
fea03cb4 PBG	44	goto out_nosemaphore;
fea03cb4 PBG	45
759496ba JW	46	if (is_user)
759496ba JW	47	flags \|= FAULT_FLAG_USER;
1cefe28f	48	retry:
1da177e4 LT	49	down_read(&mm->mmap_sem);
1da177e4 LT	50	vma = find_vma(mm, address);
4c9e1385	51	if (!vma)
1da177e4	52	goto out;
4c9e1385	53	else if (vma->vm_start <= address)
1da177e4	54	goto good_area;
4c9e1385	55	else if (!(vma->vm_flags & VM_GROWSDOWN))
1da177e4	56	goto out;
4c9e1385	57	else if (is_user && !ARCH_IS_STACKGROW(address))
1da177e4	58	goto out;
4c9e1385	59	else if (expand_stack(vma, address))
1da177e4 LT	60	goto out;
1da177e4 LT	61
3b52166c	62	good_area:
1da177e4	63	*code_out = SEGV_ACCERR;
759496ba JW	64	if (is_write) {
	65	if (!(vma->vm_flags & VM_WRITE))
	66	goto out;
	67	flags \|= FAULT_FLAG_WRITE;
	68	} else {
	69	/* Don't require VM_READ\|VM_EXEC for write faults! */
	70	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	71	goto out;
	72	}
13479d52	73
1da177e4	74	do {
83c54070	75	int fault;
1c0fe6e3	76
dcddffd4	77	fault = handle_mm_fault(vma, address, flags);
1cefe28f KC	78
	79	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	80	goto out_nosemaphore;
	81
83c54070 NP	82	if (unlikely(fault & VM_FAULT_ERROR)) {
83c54070 NP	83	if (fault & VM_FAULT_OOM) {
83c54070	84	goto out_of_memory;
33692f27 LT	85	} else if (fault & VM_FAULT_SIGSEGV) {
33692f27 LT	86	goto out;
83c54070 NP	87	} else if (fault & VM_FAULT_SIGBUS) {
	88	err = -EACCES;
	89	goto out;
	90	}
1da177e4 LT	91	BUG();
1da177e4 LT	92	}
1cefe28f KC	93	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	94	if (fault & VM_FAULT_MAJOR)
	95	current->maj_flt++;
	96	else
	97	current->min_flt++;
	98	if (fault & VM_FAULT_RETRY) {
	99	flags &= ~FAULT_FLAG_ALLOW_RETRY;
45cac65b	100	flags \|= FAULT_FLAG_TRIED;
1cefe28f KC	101
	102	goto retry;
	103	}
	104	}
83c54070	105
3b52166c PBG	106	pgd = pgd_offset(mm, address);
	107	pud = pud_offset(pgd, address);
	108	pmd = pmd_offset(pud, address);
	109	pte = pte_offset_kernel(pmd, address);
4c9e1385	110	} while (!pte_present(*pte));
1da177e4	111	err = 0;
4c9e1385 JD	112	/*
4c9e1385 JD	113	* The below warning was added in place of
cbc24afa PBG	114	* pte_mkyoung(); if (is_write) pte_mkdirty();
	115	* If it's triggered, we'd see normally a hang here (a clean pte is
	116	* marked read-only to emulate the dirty bit).
	117	* However, the generic code can mark a PTE writable but clean on a
	118	* concurrent read fault, triggering this harmlessly. So comment it out.
	119	*/
	120	#if 0
16b03678	121	WARN_ON(!pte_young(pte) \|\| (is_write && !pte_dirty(pte)));
cbc24afa	122	#endif
3b52166c PBG	123	flush_tlb_page(vma, address);
3b52166c PBG	124	out:
1da177e4	125	up_read(&mm->mmap_sem);
fea03cb4	126	out_nosemaphore:
4c9e1385	127	return err;
1da177e4	128
1da177e4	129	out_of_memory:
1c0fe6e3 NP	130	/*
	131	* We ran out of memory, call the OOM killer, and return the userspace
	132	* (which will retry the fault, or kill us if we got oom-killed).
	133	*/
	134	up_read(&mm->mmap_sem);
87134102 JW	135	if (!is_user)
87134102 JW	136	goto out_nosemaphore;
1c0fe6e3 NP	137	pagefault_out_of_memory();
1c0fe6e3 NP	138	return 0;
1da177e4	139	}
73395a00	140	EXPORT_SYMBOL(handle_page_fault);
1da177e4	141
3ef6130a RW	142	static void show_segv_info(struct uml_pt_regs *regs)
	143	{
	144	struct task_struct *tsk = current;
	145	struct faultinfo *fi = UPT_FAULTINFO(regs);
	146
	147	if (!unhandled_signal(tsk, SIGSEGV))
	148	return;
	149
	150	if (!printk_ratelimit())
	151	return;
	152
10a7e9d8	153	printk("%s%s[%d]: segfault at %lx ip %px sp %px error %x",
3ef6130a RW	154	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
	155	tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
	156	(void )UPT_IP(regs), (void )UPT_SP(regs),
	157	fi->error_code);
	158
	159	print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
	160	printk(KERN_CONT "\n");
	161	}
	162
27aa6ef3 JD	163	static void bad_segv(struct faultinfo fi, unsigned long ip)
	164	{
	165	struct siginfo si;
	166
	167	si.si_signo = SIGSEGV;
	168	si.si_code = SEGV_ACCERR;
	169	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
	170	current->thread.arch.faultinfo = fi;
	171	force_sig_info(SIGSEGV, &si, current);
	172	}
	173
3e6f2ac4 JD	174	void fatal_sigsegv(void)
	175	{
	176	force_sigsegv(SIGSEGV, current);
ccaee5f8	177	do_signal(&current->thread.regs);
3e6f2ac4 JD	178	/*
	179	* This is to tell gcc that we're not returning - do_signal
	180	* can, in general, return, but in this case, it's not, since
	181	* we just got a fatal SIGSEGV queued.
	182	*/
	183	os_dump_core();
	184	}
	185
88af2338 TM	186	/**
	187	* segv_handler() - the SIGSEGV handler
	188	* @sig: the signal number
	189	* @unused_si: the signal info struct; unused in this handler
	190	* @regs: the ptrace register information
	191	*
	192	* The handler first extracts the faultinfo from the UML ptrace regs struct.
	193	* If the userfault did not happen in an UML userspace process, bad_segv is called.
	194	* Otherwise the signal did happen in a cloned userspace process, handle it.
	195	*/
d3c1cfcd	196	void segv_handler(int sig, struct siginfo unused_si, struct uml_pt_regs regs)
c66fdd5e GS	197	{
	198	struct faultinfo * fi = UPT_FAULTINFO(regs);
	199
4c9e1385	200	if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
3ef6130a	201	show_segv_info(regs);
c66fdd5e GS	202	bad_segv(*fi, UPT_IP(regs));
	203	return;
	204	}
	205	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
	206	}
	207
c578455a BS	208	/*
	209	* We give a copy of the faultinfo in the regs to segv.
	210	* This must be done, since nesting SEGVs could overwrite
	211	* the info in the regs. A pointer to the info then would
	212	* give us bad data!
	213	*/
5d86456d	214	unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
77bf4400	215	struct uml_pt_regs *regs)
1da177e4 LT	216	{
1da177e4 LT	217	struct siginfo si;
fab95c55	218	jmp_buf *catcher;
1da177e4	219	int err;
5d86456d JD	220	int is_write = FAULT_WRITE(fi);
5d86456d JD	221	unsigned long address = FAULT_ADDRESS(fi);
1da177e4	222
bb6a1b2e	223	if (!is_user && regs)
f72c22e4 RW	224	current->thread.segv_regs = container_of(regs, struct pt_regs, regs);
f72c22e4 RW	225
4c9e1385	226	if (!is_user && (address >= start_vm) && (address < end_vm)) {
5d86456d	227	flush_tlb_kernel_vm();
f72c22e4	228	goto out;
5d86456d	229	}
4c9e1385	230	else if (current->mm == NULL) {
377fad3a	231	show_regs(container_of(regs, struct pt_regs, regs));
4c9e1385	232	panic("Segfault with no mm");
377fad3a	233	}
56b88a3b	234	else if (!is_user && address > PAGE_SIZE && address < TASK_SIZE) {
d2313084 RW	235	show_regs(container_of(regs, struct pt_regs, regs));
	236	panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx",
	237	address, ip);
	238	}
546fe1cb	239
d0b5e15f	240	if (SEGV_IS_FIXABLE(&fi))
4c9e1385 JD	241	err = handle_page_fault(address, ip, is_write, is_user,
4c9e1385 JD	242	&si.si_code);
546fe1cb PBG	243	else {
546fe1cb PBG	244	err = -EFAULT;
4c9e1385 JD	245	/*
	246	* A thread accessed NULL, we get a fault, but CR2 is invalid.
	247	* This code is used in __do_copy_from_user() of TT mode.
	248	* XXX tt mode is gone, so maybe this isn't needed any more
	249	*/
546fe1cb PBG	250	address = 0;
546fe1cb PBG	251	}
1da177e4 LT	252
1da177e4 LT	253	catcher = current->thread.fault_catcher;
4c9e1385	254	if (!err)
f72c22e4	255	goto out;
4c9e1385	256	else if (catcher != NULL) {
1da177e4	257	current->thread.fault_addr = (void *) address;
fab95c55	258	UML_LONGJMP(catcher, 1);
1d3468a6	259	}
4c9e1385	260	else if (current->thread.fault_addr != NULL)
1da177e4	261	panic("fault_addr set but no fault catcher");
4c9e1385	262	else if (!is_user && arch_fixup(ip, regs))
f72c22e4	263	goto out;
1da177e4	264
4c9e1385	265	if (!is_user) {
377fad3a	266	show_regs(container_of(regs, struct pt_regs, regs));
1d3468a6	267	panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
1da177e4	268	address, ip);
377fad3a	269	}
1da177e4	270
3ef6130a RW	271	show_segv_info(regs);
3ef6130a RW	272
3b52166c	273	if (err == -EACCES) {
1da177e4 LT	274	si.si_signo = SIGBUS;
	275	si.si_errno = 0;
	276	si.si_code = BUS_ADRERR;
4d338e1a	277	si.si_addr = (void __user *)address;
5d86456d	278	current->thread.arch.faultinfo = fi;
1da177e4	279	force_sig_info(SIGBUS, &si, current);
3b52166c PBG	280	} else {
3b52166c PBG	281	BUG_ON(err != -EFAULT);
1da177e4	282	si.si_signo = SIGSEGV;
4d338e1a	283	si.si_addr = (void __user *) address;
5d86456d	284	current->thread.arch.faultinfo = fi;
1da177e4 LT	285	force_sig_info(SIGSEGV, &si, current);
1da177e4 LT	286	}
f72c22e4 RW	287
	288	out:
	289	if (regs)
	290	current->thread.segv_regs = NULL;
	291
5d86456d	292	return 0;
1da177e4 LT	293	}
1da177e4 LT	294
d3c1cfcd	295	void relay_signal(int sig, struct siginfo si, struct uml_pt_regs regs)
1da177e4	296	{
d3c1cfcd MP	297	struct faultinfo *fi;
	298	struct siginfo clean_si;
	299
4c9e1385 JD	300	if (!UPT_IS_USER(regs)) {
	301	if (sig == SIGBUS)
	302	printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
	303	"mount likely just ran out of space\n");
1da177e4	304	panic("Kernel mode signal %d", sig);
6edf428e JD	305	}
6edf428e JD	306
9226b838 JD	307	arch_examine_signal(sig, regs);
9226b838 JD	308
d3c1cfcd MP	309	memset(&clean_si, 0, sizeof(clean_si));
	310	clean_si.si_signo = si->si_signo;
	311	clean_si.si_errno = si->si_errno;
	312	clean_si.si_code = si->si_code;
	313	switch (sig) {
	314	case SIGILL:
	315	case SIGFPE:
	316	case SIGSEGV:
	317	case SIGBUS:
	318	case SIGTRAP:
	319	fi = UPT_FAULTINFO(regs);
	320	clean_si.si_addr = (void __user ) FAULT_ADDRESS(fi);
	321	current->thread.arch.faultinfo = *fi;
	322	#ifdef __ARCH_SI_TRAPNO
	323	clean_si.si_trapno = si->si_trapno;
	324	#endif
	325	break;
	326	default:
	327	printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
	328	sig, si->si_code);
	329	}
	330
	331	force_sig_info(sig, &clean_si, current);
1da177e4 LT	332	}
1da177e4 LT	333
d3c1cfcd	334	void bus_handler(int sig, struct siginfo si, struct uml_pt_regs regs)
1da177e4	335	{
4c9e1385	336	if (current->thread.fault_catcher != NULL)
fab95c55	337	UML_LONGJMP(current->thread.fault_catcher, 1);
d3c1cfcd MP	338	else
d3c1cfcd MP	339	relay_signal(sig, si, regs);
1da177e4 LT	340	}
1da177e4 LT	341
d3c1cfcd	342	void winch(int sig, struct siginfo unused_si, struct uml_pt_regs regs)
1da177e4 LT	343	{
	344	do_IRQ(WINCH_IRQ, regs);
	345	}
	346
	347	void trap_init(void)
	348	{
	349	}