[GitHub/mt8127/android_kernel_alcatel_ttab.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.h>
#include <linux/hardirq.h>
#include <linux/module.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 during atomic operation, don't take the fault, just
	 * fail.
	 */
	if (in_atomic())
		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(mm, 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_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 %p sp %p 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();
	/*
	 * 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();
}

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 && (address >= start_vm) && (address < end_vm)) {
		flush_tlb_kernel_vm();
		return 0;
	}
	else if (current->mm == NULL) {
		show_regs(container_of(regs, struct pt_regs, regs));
		panic("Segfault with no mm");
	}

	if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_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)
		return 0;
	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))
		return 0;

	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);
	}
	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 JD	6	#include <linux/mm.h>
	7	#include <linux/sched.h>
	8	#include <linux/hardirq.h>
73395a00	9	#include <linux/module.h>
4c9e1385 JD	10	#include <asm/current.h>
	11	#include <asm/pgtable.h>
	12	#include <asm/tlbflush.h>
37185b33 AV	13	#include <arch.h>
	14	#include <as-layout.h>
	15	#include <kern_util.h>
	16	#include <os.h>
	17	#include <skas.h>
1da177e4	18
4c9e1385 JD	19	/*
	20	* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
	21	* segv().
	22	*/
1d3468a6	23	int handle_page_fault(unsigned long address, unsigned long ip,
1da177e4 LT	24	int is_write, int is_user, int *code_out)
	25	{
	26	struct mm_struct *mm = current->mm;
	27	struct vm_area_struct *vma;
	28	pgd_t *pgd;
	29	pud_t *pud;
	30	pmd_t *pmd;
	31	pte_t *pte;
1da177e4	32	int err = -EFAULT;
e2ec2c2b	33	unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
1da177e4 LT	34
1da177e4 LT	35	*code_out = SEGV_MAPERR;
fea03cb4	36
4c9e1385 JD	37	/*
	38	* If the fault was during atomic operation, don't take the fault, just
	39	* fail.
	40	*/
fea03cb4 PBG	41	if (in_atomic())
	42	goto out_nosemaphore;
	43
e2ec2c2b JW	44	if (is_user)
e2ec2c2b JW	45	flags \|= FAULT_FLAG_USER;
1cefe28f	46	retry:
1da177e4 LT	47	down_read(&mm->mmap_sem);
1da177e4 LT	48	vma = find_vma(mm, address);
4c9e1385	49	if (!vma)
1da177e4	50	goto out;
4c9e1385	51	else if (vma->vm_start <= address)
1da177e4	52	goto good_area;
4c9e1385	53	else if (!(vma->vm_flags & VM_GROWSDOWN))
1da177e4	54	goto out;
4c9e1385	55	else if (is_user && !ARCH_IS_STACKGROW(address))
1da177e4	56	goto out;
4c9e1385	57	else if (expand_stack(vma, address))
1da177e4 LT	58	goto out;
1da177e4 LT	59
3b52166c	60	good_area:
1da177e4	61	*code_out = SEGV_ACCERR;
e2ec2c2b JW	62	if (is_write) {
	63	if (!(vma->vm_flags & VM_WRITE))
	64	goto out;
	65	flags \|= FAULT_FLAG_WRITE;
	66	} else {
	67	/* Don't require VM_READ\|VM_EXEC for write faults! */
	68	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	69	goto out;
	70	}
13479d52	71
1da177e4	72	do {
83c54070	73	int fault;
1c0fe6e3	74
1cefe28f KC	75	fault = handle_mm_fault(mm, vma, address, flags);
	76
	77	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	78	goto out_nosemaphore;
	79
83c54070 NP	80	if (unlikely(fault & VM_FAULT_ERROR)) {
83c54070 NP	81	if (fault & VM_FAULT_OOM) {
83c54070 NP	82	goto out_of_memory;
	83	} else if (fault & VM_FAULT_SIGBUS) {
	84	err = -EACCES;
	85	goto out;
	86	}
1da177e4 LT	87	BUG();
1da177e4 LT	88	}
1cefe28f KC	89	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	90	if (fault & VM_FAULT_MAJOR)
	91	current->maj_flt++;
	92	else
	93	current->min_flt++;
	94	if (fault & VM_FAULT_RETRY) {
	95	flags &= ~FAULT_FLAG_ALLOW_RETRY;
45cac65b	96	flags \|= FAULT_FLAG_TRIED;
1cefe28f KC	97
	98	goto retry;
	99	}
	100	}
83c54070	101
3b52166c PBG	102	pgd = pgd_offset(mm, address);
	103	pud = pud_offset(pgd, address);
	104	pmd = pmd_offset(pud, address);
	105	pte = pte_offset_kernel(pmd, address);
4c9e1385	106	} while (!pte_present(*pte));
1da177e4	107	err = 0;
4c9e1385 JD	108	/*
4c9e1385 JD	109	* The below warning was added in place of
cbc24afa PBG	110	* pte_mkyoung(); if (is_write) pte_mkdirty();
	111	* If it's triggered, we'd see normally a hang here (a clean pte is
	112	* marked read-only to emulate the dirty bit).
	113	* However, the generic code can mark a PTE writable but clean on a
	114	* concurrent read fault, triggering this harmlessly. So comment it out.
	115	*/
	116	#if 0
16b03678	117	WARN_ON(!pte_young(pte) \|\| (is_write && !pte_dirty(pte)));
cbc24afa	118	#endif
3b52166c PBG	119	flush_tlb_page(vma, address);
3b52166c PBG	120	out:
1da177e4	121	up_read(&mm->mmap_sem);
fea03cb4	122	out_nosemaphore:
4c9e1385	123	return err;
1da177e4	124
1da177e4	125	out_of_memory:
1c0fe6e3 NP	126	/*
	127	* We ran out of memory, call the OOM killer, and return the userspace
	128	* (which will retry the fault, or kill us if we got oom-killed).
	129	*/
	130	up_read(&mm->mmap_sem);
086c6cc5 JW	131	if (!is_user)
086c6cc5 JW	132	goto out_nosemaphore;
1c0fe6e3 NP	133	pagefault_out_of_memory();
1c0fe6e3 NP	134	return 0;
1da177e4	135	}
73395a00	136	EXPORT_SYMBOL(handle_page_fault);
1da177e4	137
3ef6130a RW	138	static void show_segv_info(struct uml_pt_regs *regs)
	139	{
	140	struct task_struct *tsk = current;
	141	struct faultinfo *fi = UPT_FAULTINFO(regs);
	142
	143	if (!unhandled_signal(tsk, SIGSEGV))
	144	return;
	145
	146	if (!printk_ratelimit())
	147	return;
	148
	149	printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x",
	150	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
	151	tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
	152	(void )UPT_IP(regs), (void )UPT_SP(regs),
	153	fi->error_code);
	154
	155	print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
	156	printk(KERN_CONT "\n");
	157	}
	158
27aa6ef3 JD	159	static void bad_segv(struct faultinfo fi, unsigned long ip)
	160	{
	161	struct siginfo si;
	162
	163	si.si_signo = SIGSEGV;
	164	si.si_code = SEGV_ACCERR;
	165	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
	166	current->thread.arch.faultinfo = fi;
	167	force_sig_info(SIGSEGV, &si, current);
	168	}
	169
3e6f2ac4 JD	170	void fatal_sigsegv(void)
	171	{
	172	force_sigsegv(SIGSEGV, current);
	173	do_signal();
	174	/*
	175	* This is to tell gcc that we're not returning - do_signal
	176	* can, in general, return, but in this case, it's not, since
	177	* we just got a fatal SIGSEGV queued.
	178	*/
	179	os_dump_core();
	180	}
	181
d3c1cfcd	182	void segv_handler(int sig, struct siginfo unused_si, struct uml_pt_regs regs)
c66fdd5e GS	183	{
	184	struct faultinfo * fi = UPT_FAULTINFO(regs);
	185
4c9e1385	186	if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
3ef6130a	187	show_segv_info(regs);
c66fdd5e GS	188	bad_segv(*fi, UPT_IP(regs));
	189	return;
	190	}
	191	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
	192	}
	193
c578455a BS	194	/*
	195	* We give a copy of the faultinfo in the regs to segv.
	196	* This must be done, since nesting SEGVs could overwrite
	197	* the info in the regs. A pointer to the info then would
	198	* give us bad data!
	199	*/
5d86456d	200	unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
77bf4400	201	struct uml_pt_regs *regs)
1da177e4 LT	202	{
1da177e4 LT	203	struct siginfo si;
fab95c55	204	jmp_buf *catcher;
1da177e4	205	int err;
5d86456d JD	206	int is_write = FAULT_WRITE(fi);
5d86456d JD	207	unsigned long address = FAULT_ADDRESS(fi);
1da177e4	208
4c9e1385	209	if (!is_user && (address >= start_vm) && (address < end_vm)) {
5d86456d JD	210	flush_tlb_kernel_vm();
	211	return 0;
	212	}
4c9e1385	213	else if (current->mm == NULL) {
377fad3a	214	show_regs(container_of(regs, struct pt_regs, regs));
4c9e1385	215	panic("Segfault with no mm");
377fad3a	216	}
546fe1cb	217
be662a18	218	if (SEGV_IS_FIXABLE(&fi) \|\| SEGV_MAYBE_FIXABLE(&fi))
4c9e1385 JD	219	err = handle_page_fault(address, ip, is_write, is_user,
4c9e1385 JD	220	&si.si_code);
546fe1cb PBG	221	else {
546fe1cb PBG	222	err = -EFAULT;
4c9e1385 JD	223	/*
	224	* A thread accessed NULL, we get a fault, but CR2 is invalid.
	225	* This code is used in __do_copy_from_user() of TT mode.
	226	* XXX tt mode is gone, so maybe this isn't needed any more
	227	*/
546fe1cb PBG	228	address = 0;
546fe1cb PBG	229	}
1da177e4 LT	230
1da177e4 LT	231	catcher = current->thread.fault_catcher;
4c9e1385	232	if (!err)
5d86456d	233	return 0;
4c9e1385	234	else if (catcher != NULL) {
1da177e4	235	current->thread.fault_addr = (void *) address;
fab95c55	236	UML_LONGJMP(catcher, 1);
1d3468a6	237	}
4c9e1385	238	else if (current->thread.fault_addr != NULL)
1da177e4	239	panic("fault_addr set but no fault catcher");
4c9e1385	240	else if (!is_user && arch_fixup(ip, regs))
5d86456d	241	return 0;
1da177e4	242
4c9e1385	243	if (!is_user) {
377fad3a	244	show_regs(container_of(regs, struct pt_regs, regs));
1d3468a6	245	panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
1da177e4	246	address, ip);
377fad3a	247	}
1da177e4	248
3ef6130a RW	249	show_segv_info(regs);
3ef6130a RW	250
3b52166c	251	if (err == -EACCES) {
1da177e4 LT	252	si.si_signo = SIGBUS;
	253	si.si_errno = 0;
	254	si.si_code = BUS_ADRERR;
4d338e1a	255	si.si_addr = (void __user *)address;
5d86456d	256	current->thread.arch.faultinfo = fi;
1da177e4	257	force_sig_info(SIGBUS, &si, current);
3b52166c PBG	258	} else {
3b52166c PBG	259	BUG_ON(err != -EFAULT);
1da177e4	260	si.si_signo = SIGSEGV;
4d338e1a	261	si.si_addr = (void __user *) address;
5d86456d	262	current->thread.arch.faultinfo = fi;
1da177e4 LT	263	force_sig_info(SIGSEGV, &si, current);
1da177e4 LT	264	}
5d86456d	265	return 0;
1da177e4 LT	266	}
1da177e4 LT	267
d3c1cfcd	268	void relay_signal(int sig, struct siginfo si, struct uml_pt_regs regs)
1da177e4	269	{
d3c1cfcd MP	270	struct faultinfo *fi;
	271	struct siginfo clean_si;
	272
4c9e1385 JD	273	if (!UPT_IS_USER(regs)) {
	274	if (sig == SIGBUS)
	275	printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
	276	"mount likely just ran out of space\n");
1da177e4	277	panic("Kernel mode signal %d", sig);
6edf428e JD	278	}
6edf428e JD	279
9226b838 JD	280	arch_examine_signal(sig, regs);
9226b838 JD	281
d3c1cfcd MP	282	memset(&clean_si, 0, sizeof(clean_si));
	283	clean_si.si_signo = si->si_signo;
	284	clean_si.si_errno = si->si_errno;
	285	clean_si.si_code = si->si_code;
	286	switch (sig) {
	287	case SIGILL:
	288	case SIGFPE:
	289	case SIGSEGV:
	290	case SIGBUS:
	291	case SIGTRAP:
	292	fi = UPT_FAULTINFO(regs);
	293	clean_si.si_addr = (void __user ) FAULT_ADDRESS(fi);
	294	current->thread.arch.faultinfo = *fi;
	295	#ifdef __ARCH_SI_TRAPNO
	296	clean_si.si_trapno = si->si_trapno;
	297	#endif
	298	break;
	299	default:
	300	printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
	301	sig, si->si_code);
	302	}
	303
	304	force_sig_info(sig, &clean_si, current);
1da177e4 LT	305	}
1da177e4 LT	306
d3c1cfcd	307	void bus_handler(int sig, struct siginfo si, struct uml_pt_regs regs)
1da177e4	308	{
4c9e1385	309	if (current->thread.fault_catcher != NULL)
fab95c55	310	UML_LONGJMP(current->thread.fault_catcher, 1);
d3c1cfcd MP	311	else
d3c1cfcd MP	312	relay_signal(sig, si, regs);
1da177e4 LT	313	}
1da177e4 LT	314
d3c1cfcd	315	void winch(int sig, struct siginfo unused_si, struct uml_pt_regs regs)
1da177e4 LT	316	{
	317	do_IRQ(WINCH_IRQ, regs);
	318	}
	319
	320	void trap_init(void)
	321	{
	322	}