[deliverable/linux.git] / arch / sparc / mm / fault_32.c

/*
 * fault.c:  Page fault handlers for the Sparc.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 */

#include <asm/head.h>

#include <linux/string.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/perf_event.h>
#include <linux/interrupt.h>
#include <linux/kdebug.h>

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/smp.h>
#include <asm/traps.h>
#include <asm/uaccess.h>

int show_unhandled_signals = 1;

static void unhandled_fault(unsigned long, struct task_struct *,
		struct pt_regs *) __attribute__ ((noreturn));

static void __noreturn unhandled_fault(unsigned long address,
				       struct task_struct *tsk,
				       struct pt_regs *regs)
{
	if ((unsigned long) address < PAGE_SIZE) {
		printk(KERN_ALERT
		    "Unable to handle kernel NULL pointer dereference\n");
	} else {
		printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
		       address);
	}
	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
		(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
		(tsk->mm ? (unsigned long) tsk->mm->pgd :
			(unsigned long) tsk->active_mm->pgd));
	die_if_kernel("Oops", regs);
}

asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
			    unsigned long address)
{
	struct pt_regs regs;
	unsigned long g2;
	unsigned int insn;
	int i;

	i = search_extables_range(ret_pc, &g2);
	switch (i) {
	case 3:
		/* load & store will be handled by fixup */
		return 3;

	case 1:
		/* store will be handled by fixup, load will bump out */
		/* for _to_ macros */
		insn = *((unsigned int *) pc);
		if ((insn >> 21) & 1)
			return 1;
		break;

	case 2:
		/* load will be handled by fixup, store will bump out */
		/* for _from_ macros */
		insn = *((unsigned int *) pc);
		if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
			return 2;
		break;

	default:
		break;
	}

	memset(&regs, 0, sizeof(regs));
	regs.pc = pc;
	regs.npc = pc + 4;
	__asm__ __volatile__(
		"rd %%psr, %0\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n" : "=r" (regs.psr));
	unhandled_fault(address, current, &regs);

	/* Not reached */
	return 0;
}

static inline void
show_signal_msg(struct pt_regs *regs, int sig, int code,
		unsigned long address, struct task_struct *tsk)
{
	if (!unhandled_signal(tsk, sig))
		return;

	if (!printk_ratelimit())
		return;

	printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
	       task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
	       tsk->comm, task_pid_nr(tsk), address,
	       (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
	       (void *)regs->u_regs[UREG_FP], code);

	print_vma_addr(KERN_CONT " in ", regs->pc);

	printk(KERN_CONT "\n");
}

static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
			       unsigned long addr)
{
	siginfo_t info;

	info.si_signo = sig;
	info.si_code = code;
	info.si_errno = 0;
	info.si_addr = (void __user *) addr;
	info.si_trapno = 0;

	if (unlikely(show_unhandled_signals))
		show_signal_msg(regs, sig, info.si_code,
				addr, current);

	force_sig_info (sig, &info, current);
}

extern unsigned long safe_compute_effective_address(struct pt_regs *,
						    unsigned int);

static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
{
	unsigned int insn;

	if (text_fault)
		return regs->pc;

	if (regs->psr & PSR_PS)
		insn = *(unsigned int *) regs->pc;
	else
		__get_user(insn, (unsigned int *) regs->pc);

	return safe_compute_effective_address(regs, insn);
}

static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
				      int text_fault)
{
	unsigned long addr = compute_si_addr(regs, text_fault);

	__do_fault_siginfo(code, sig, regs, addr);
}

asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
			       unsigned long address)
{
	struct vm_area_struct *vma;
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->mm;
	unsigned int fixup;
	unsigned long g2;
	int from_user = !(regs->psr & PSR_PS);
	int fault, code;
	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
			      (write ? FAULT_FLAG_WRITE : 0));

	if (text_fault)
		address = regs->pc;

	/*
	 * We fault-in kernel-space virtual memory on-demand. The
	 * 'reference' page table is init_mm.pgd.
	 *
	 * NOTE! We MUST NOT take any locks for this case. We may
	 * be in an interrupt or a critical region, and should
	 * only copy the information from the master page table,
	 * nothing more.
	 */
	code = SEGV_MAPERR;
	if (address >= TASK_SIZE)
		goto vmalloc_fault;

	/*
	 * If we're in an interrupt or have no user
	 * context, we must not take the fault..
	 */
	if (in_atomic() || !mm)
		goto no_context;

	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

retry:
	down_read(&mm->mmap_sem);

	if (!from_user && address >= PAGE_OFFSET)
		goto bad_area;

	vma = find_vma(mm, address);
	if (!vma)
		goto bad_area;
	if (vma->vm_start <= address)
		goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
		goto bad_area;
	if (expand_stack(vma, address))
		goto bad_area;
	/*
	 * Ok, we have a good vm_area for this memory access, so
	 * we can handle it..
	 */
good_area:
	code = SEGV_ACCERR;
	if (write) {
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
	} else {
		/* Allow reads even for write-only mappings */
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto bad_area;
	}

	/*
	 * If for any reason at all we couldn't handle the fault,
	 * make sure we exit gracefully rather than endlessly redo
	 * the fault.
	 */
	fault = handle_mm_fault(mm, vma, address, flags);

	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
		return;

	if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM)
			goto out_of_memory;
		else if (fault & VM_FAULT_SIGBUS)
			goto do_sigbus;
		BUG();
	}

	if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR) {
			current->maj_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
				      1, regs, address);
		} else {
			current->min_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
				      1, regs, address);
		}
		if (fault & VM_FAULT_RETRY) {
			flags &= ~FAULT_FLAG_ALLOW_RETRY;
			flags |= FAULT_FLAG_TRIED;

			/* No need to up_read(&mm->mmap_sem) as we would
			 * have already released it in __lock_page_or_retry
			 * in mm/filemap.c.
			 */

			goto retry;
		}
	}

	up_read(&mm->mmap_sem);
	return;

	/*
	 * Something tried to access memory that isn't in our memory map..
	 * Fix it, but check if it's kernel or user first..
	 */
bad_area:
	up_read(&mm->mmap_sem);

bad_area_nosemaphore:
	/* User mode accesses just cause a SIGSEGV */
	if (from_user) {
		do_fault_siginfo(code, SIGSEGV, regs, text_fault);
		return;
	}

	/* Is this in ex_table? */
no_context:
	g2 = regs->u_regs[UREG_G2];
	if (!from_user) {
		fixup = search_extables_range(regs->pc, &g2);
		/* Values below 10 are reserved for other things */
		if (fixup > 10) {
			extern const unsigned __memset_start[];
			extern const unsigned __memset_end[];
			extern const unsigned __csum_partial_copy_start[];
			extern const unsigned __csum_partial_copy_end[];

#ifdef DEBUG_EXCEPTIONS
			printk("Exception: PC<%08lx> faddr<%08lx>\n",
			       regs->pc, address);
			printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
				regs->pc, fixup, g2);
#endif
			if ((regs->pc >= (unsigned long)__memset_start &&
			     regs->pc < (unsigned long)__memset_end) ||
			    (regs->pc >= (unsigned long)__csum_partial_copy_start &&
			     regs->pc < (unsigned long)__csum_partial_copy_end)) {
				regs->u_regs[UREG_I4] = address;
				regs->u_regs[UREG_I5] = regs->pc;
			}
			regs->u_regs[UREG_G2] = g2;
			regs->pc = fixup;
			regs->npc = regs->pc + 4;
			return;
		}
	}

	unhandled_fault(address, tsk, regs);
	do_exit(SIGKILL);

/*
 * We ran out of memory, or some other thing happened to us that made
 * us unable to handle the page fault gracefully.
 */
out_of_memory:
	up_read(&mm->mmap_sem);
	if (from_user) {
		pagefault_out_of_memory();
		return;
	}
	goto no_context;

do_sigbus:
	up_read(&mm->mmap_sem);
	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
	if (!from_user)
		goto no_context;

vmalloc_fault:
	{
		/*
		 * Synchronize this task's top level page-table
		 * with the 'reference' page table.
		 */
		int offset = pgd_index(address);
		pgd_t *pgd, *pgd_k;
		pmd_t *pmd, *pmd_k;

		pgd = tsk->active_mm->pgd + offset;
		pgd_k = init_mm.pgd + offset;

		if (!pgd_present(*pgd)) {
			if (!pgd_present(*pgd_k))
				goto bad_area_nosemaphore;
			pgd_val(*pgd) = pgd_val(*pgd_k);
			return;
		}

		pmd = pmd_offset(pgd, address);
		pmd_k = pmd_offset(pgd_k, address);

		if (pmd_present(*pmd) || !pmd_present(*pmd_k))
			goto bad_area_nosemaphore;

		*pmd = *pmd_k;
		return;
	}
}

/* This always deals with user addresses. */
static void force_user_fault(unsigned long address, int write)
{
	struct vm_area_struct *vma;
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->mm;
	int code;

	code = SEGV_MAPERR;

	down_read(&mm->mmap_sem);
	vma = find_vma(mm, address);
	if (!vma)
		goto bad_area;
	if (vma->vm_start <= address)
		goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
		goto bad_area;
	if (expand_stack(vma, address))
		goto bad_area;
good_area:
	code = SEGV_ACCERR;
	if (write) {
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
	} else {
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto bad_area;
	}
	switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
	case VM_FAULT_SIGBUS:
	case VM_FAULT_OOM:
		goto do_sigbus;
	}
	up_read(&mm->mmap_sem);
	return;
bad_area:
	up_read(&mm->mmap_sem);
	__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
	return;

do_sigbus:
	up_read(&mm->mmap_sem);
	__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
}

static void check_stack_aligned(unsigned long sp)
{
	if (sp & 0x7UL)
		force_sig(SIGILL, current);
}

void window_overflow_fault(void)
{
	unsigned long sp;

	sp = current_thread_info()->rwbuf_stkptrs[0];
	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 1);
	force_user_fault(sp, 1);

	check_stack_aligned(sp);
}

void window_underflow_fault(unsigned long sp)
{
	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 0);
	force_user_fault(sp, 0);

	check_stack_aligned(sp);
}

void window_ret_fault(struct pt_regs *regs)
{
	unsigned long sp;

	sp = regs->u_regs[UREG_FP];
	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
		force_user_fault(sp + 0x38, 0);
	force_user_fault(sp, 0);

	check_stack_aligned(sp);
}
Commit	Line	Data
88278ca2	1	/*
1da177e4 LT	2	* fault.c: Page fault handlers for the Sparc.
	3	*
	4	* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
	5	* Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
	6	* Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
	7	*/
	8
	9	#include <asm/head.h>
	10
	11	#include <linux/string.h>
	12	#include <linux/types.h>
	13	#include <linux/sched.h>
	14	#include <linux/ptrace.h>
	15	#include <linux/mman.h>
	16	#include <linux/threads.h>
	17	#include <linux/kernel.h>
	18	#include <linux/signal.h>
	19	#include <linux/mm.h>
	20	#include <linux/smp.h>
a084b667	21	#include <linux/perf_event.h>
1da177e4	22	#include <linux/interrupt.h>
1eeb66a1	23	#include <linux/kdebug.h>
1da177e4	24
1da177e4 LT	25	#include <asm/page.h>
1da177e4 LT	26	#include <asm/pgtable.h>
1da177e4 LT	27	#include <asm/openprom.h>
	28	#include <asm/oplib.h>
	29	#include <asm/smp.h>
	30	#include <asm/traps.h>
1da177e4 LT	31	#include <asm/uaccess.h>
1da177e4 LT	32
4b177647 DM	33	int show_unhandled_signals = 1;
4b177647 DM	34
1da177e4 LT	35	static void unhandled_fault(unsigned long, struct task_struct *,
	36	struct pt_regs *) __attribute__ ((noreturn));
	37
70168dfa SR	38	static void __noreturn unhandled_fault(unsigned long address,
	39	struct task_struct *tsk,
	40	struct pt_regs *regs)
1da177e4	41	{
70168dfa	42	if ((unsigned long) address < PAGE_SIZE) {
1da177e4 LT	43	printk(KERN_ALERT
	44	"Unable to handle kernel NULL pointer dereference\n");
	45	} else {
70168dfa SR	46	printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
70168dfa SR	47	address);
1da177e4 LT	48	}
	49	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
	50	(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
	51	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
	52	(tsk->mm ? (unsigned long) tsk->mm->pgd :
70168dfa	53	(unsigned long) tsk->active_mm->pgd));
1da177e4 LT	54	die_if_kernel("Oops", regs);
	55	}
	56
70168dfa	57	asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
1da177e4 LT	58	unsigned long address)
	59	{
	60	struct pt_regs regs;
	61	unsigned long g2;
	62	unsigned int insn;
	63	int i;
70168dfa	64
1da177e4 LT	65	i = search_extables_range(ret_pc, &g2);
	66	switch (i) {
	67	case 3:
	68	/* load & store will be handled by fixup */
	69	return 3;
	70
	71	case 1:
	72	/* store will be handled by fixup, load will bump out */
	73	/* for _to_ macros */
	74	insn = ((unsigned int ) pc);
	75	if ((insn >> 21) & 1)
	76	return 1;
	77	break;
	78
	79	case 2:
	80	/* load will be handled by fixup, store will bump out */
	81	/* for _from_ macros */
	82	insn = ((unsigned int ) pc);
	83	if (!((insn >> 21) & 1) \|\| ((insn>>19)&0x3f) == 15)
70168dfa SR	84	return 2;
70168dfa SR	85	break;
1da177e4 LT	86
	87	default:
	88	break;
6cb79b3f	89	}
1da177e4	90
70168dfa	91	memset(&regs, 0, sizeof(regs));
1da177e4 LT	92	regs.pc = pc;
	93	regs.npc = pc + 4;
	94	__asm__ __volatile__(
	95	"rd %%psr, %0\n\t"
	96	"nop\n\t"
	97	"nop\n\t"
	98	"nop\n" : "=r" (regs.psr));
	99	unhandled_fault(address, current, &regs);
	100
	101	/* Not reached */
	102	return 0;
	103	}
	104
4b177647 DM	105	static inline void
	106	show_signal_msg(struct pt_regs *regs, int sig, int code,
	107	unsigned long address, struct task_struct *tsk)
	108	{
	109	if (!unhandled_signal(tsk, sig))
	110	return;
	111
	112	if (!printk_ratelimit())
	113	return;
	114
	115	printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
	116	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
	117	tsk->comm, task_pid_nr(tsk), address,
	118	(void )regs->pc, (void )regs->u_regs[UREG_I7],
	119	(void *)regs->u_regs[UREG_FP], code);
	120
	121	print_vma_addr(KERN_CONT " in ", regs->pc);
	122
	123	printk(KERN_CONT "\n");
	124	}
	125
	126	static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	127	unsigned long addr)
	128	{
	129	siginfo_t info;
	130
	131	info.si_signo = sig;
	132	info.si_code = code;
	133	info.si_errno = 0;
	134	info.si_addr = (void __user *) addr;
	135	info.si_trapno = 0;
	136
	137	if (unlikely(show_unhandled_signals))
	138	show_signal_msg(regs, sig, info.si_code,
	139	addr, current);
	140
	141	force_sig_info (sig, &info, current);
	142	}
	143
1da177e4 LT	144	extern unsigned long safe_compute_effective_address(struct pt_regs *,
	145	unsigned int);
	146
	147	static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
	148	{
	149	unsigned int insn;
	150
	151	if (text_fault)
	152	return regs->pc;
	153
70168dfa	154	if (regs->psr & PSR_PS)
1da177e4	155	insn = (unsigned int ) regs->pc;
70168dfa	156	else
1da177e4	157	__get_user(insn, (unsigned int *) regs->pc);
1da177e4 LT	158
	159	return safe_compute_effective_address(regs, insn);
	160	}
	161
4b177647 DM	162	static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	163	int text_fault)
	164	{
	165	unsigned long addr = compute_si_addr(regs, text_fault);
	166
	167	__do_fault_siginfo(code, sig, regs, addr);
	168	}
	169
1da177e4 LT	170	asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
	171	unsigned long address)
	172	{
	173	struct vm_area_struct *vma;
	174	struct task_struct *tsk = current;
	175	struct mm_struct *mm = tsk->mm;
	176	unsigned int fixup;
	177	unsigned long g2;
1da177e4	178	int from_user = !(regs->psr & PSR_PS);
4b177647	179	int fault, code;
c29554f5 KC	180	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE \|
c29554f5 KC	181	(write ? FAULT_FLAG_WRITE : 0));
1da177e4	182
70168dfa	183	if (text_fault)
1da177e4 LT	184	address = regs->pc;
	185
	186	/*
	187	* We fault-in kernel-space virtual memory on-demand. The
	188	* 'reference' page table is init_mm.pgd.
	189	*
	190	* NOTE! We MUST NOT take any locks for this case. We may
	191	* be in an interrupt or a critical region, and should
	192	* only copy the information from the master page table,
	193	* nothing more.
	194	*/
c816be7b	195	code = SEGV_MAPERR;
582a0bae	196	if (address >= TASK_SIZE)
1da177e4 LT	197	goto vmalloc_fault;
1da177e4 LT	198
1da177e4 LT	199	/*
	200	* If we're in an interrupt or have no user
	201	* context, we must not take the fault..
	202	*/
70168dfa SR	203	if (in_atomic() \|\| !mm)
70168dfa SR	204	goto no_context;
1da177e4	205
a8b0ca17	206	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
a084b667	207
c29554f5	208	retry:
1da177e4 LT	209	down_read(&mm->mmap_sem);
1da177e4 LT	210
70168dfa	211	if (!from_user && address >= PAGE_OFFSET)
1da177e4 LT	212	goto bad_area;
	213
	214	vma = find_vma(mm, address);
70168dfa	215	if (!vma)
1da177e4	216	goto bad_area;
70168dfa	217	if (vma->vm_start <= address)
1da177e4	218	goto good_area;
70168dfa	219	if (!(vma->vm_flags & VM_GROWSDOWN))
1da177e4	220	goto bad_area;
70168dfa	221	if (expand_stack(vma, address))
1da177e4 LT	222	goto bad_area;
	223	/*
	224	* Ok, we have a good vm_area for this memory access, so
	225	* we can handle it..
	226	*/
	227	good_area:
4b177647	228	code = SEGV_ACCERR;
70168dfa SR	229	if (write) {
70168dfa SR	230	if (!(vma->vm_flags & VM_WRITE))
1da177e4 LT	231	goto bad_area;
	232	} else {
	233	/* Allow reads even for write-only mappings */
70168dfa	234	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
1da177e4 LT	235	goto bad_area;
	236	}
	237
	238	/*
	239	* If for any reason at all we couldn't handle the fault,
	240	* make sure we exit gracefully rather than endlessly redo
	241	* the fault.
	242	*/
c29554f5 KC	243	fault = handle_mm_fault(mm, vma, address, flags);
	244
	245	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	246	return;
	247
83c54070 NP	248	if (unlikely(fault & VM_FAULT_ERROR)) {
	249	if (fault & VM_FAULT_OOM)
	250	goto out_of_memory;
	251	else if (fault & VM_FAULT_SIGBUS)
	252	goto do_sigbus;
	253	BUG();
	254	}
c29554f5 KC	255
	256	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	257	if (fault & VM_FAULT_MAJOR) {
	258	current->maj_flt++;
	259	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
	260	1, regs, address);
	261	} else {
	262	current->min_flt++;
	263	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
	264	1, regs, address);
	265	}
	266	if (fault & VM_FAULT_RETRY) {
	267	flags &= ~FAULT_FLAG_ALLOW_RETRY;
45cac65b	268	flags \|= FAULT_FLAG_TRIED;
c29554f5 KC	269
	270	/* No need to up_read(&mm->mmap_sem) as we would
	271	* have already released it in __lock_page_or_retry
	272	* in mm/filemap.c.
	273	*/
	274
	275	goto retry;
	276	}
a084b667	277	}
c29554f5	278
1da177e4 LT	279	up_read(&mm->mmap_sem);
	280	return;
	281
	282	/*
	283	* Something tried to access memory that isn't in our memory map..
	284	* Fix it, but check if it's kernel or user first..
	285	*/
	286	bad_area:
	287	up_read(&mm->mmap_sem);
	288
	289	bad_area_nosemaphore:
	290	/* User mode accesses just cause a SIGSEGV */
4b177647 DM	291	if (from_user) {
4b177647 DM	292	do_fault_siginfo(code, SIGSEGV, regs, text_fault);
1da177e4 LT	293	return;
	294	}
	295
	296	/* Is this in ex_table? */
	297	no_context:
	298	g2 = regs->u_regs[UREG_G2];
0157141a SR	299	if (!from_user) {
0157141a SR	300	fixup = search_extables_range(regs->pc, &g2);
70168dfa SR	301	/* Values below 10 are reserved for other things */
70168dfa SR	302	if (fixup > 10) {
1da177e4 LT	303	extern const unsigned __memset_start[];
	304	extern const unsigned __memset_end[];
	305	extern const unsigned __csum_partial_copy_start[];
	306	extern const unsigned __csum_partial_copy_end[];
	307
	308	#ifdef DEBUG_EXCEPTIONS
70168dfa SR	309	printk("Exception: PC<%08lx> faddr<%08lx>\n",
70168dfa SR	310	regs->pc, address);
1da177e4 LT	311	printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
	312	regs->pc, fixup, g2);
	313	#endif
	314	if ((regs->pc >= (unsigned long)__memset_start &&
	315	regs->pc < (unsigned long)__memset_end) \|\|
	316	(regs->pc >= (unsigned long)__csum_partial_copy_start &&
	317	regs->pc < (unsigned long)__csum_partial_copy_end)) {
70168dfa	318	regs->u_regs[UREG_I4] = address;
1da177e4 LT	319	regs->u_regs[UREG_I5] = regs->pc;
	320	}
	321	regs->u_regs[UREG_G2] = g2;
	322	regs->pc = fixup;
	323	regs->npc = regs->pc + 4;
	324	return;
	325	}
	326	}
70168dfa SR	327
70168dfa SR	328	unhandled_fault(address, tsk, regs);
1da177e4 LT	329	do_exit(SIGKILL);
	330
	331	/*
	332	* We ran out of memory, or some other thing happened to us that made
	333	* us unable to handle the page fault gracefully.
	334	*/
	335	out_of_memory:
	336	up_read(&mm->mmap_sem);
a923c28f DM	337	if (from_user) {
	338	pagefault_out_of_memory();
	339	return;
	340	}
1da177e4 LT	341	goto no_context;
	342
	343	do_sigbus:
	344	up_read(&mm->mmap_sem);
4b177647	345	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
1da177e4 LT	346	if (!from_user)
	347	goto no_context;
	348
	349	vmalloc_fault:
	350	{
	351	/*
	352	* Synchronize this task's top level page-table
	353	* with the 'reference' page table.
	354	*/
	355	int offset = pgd_index(address);
	356	pgd_t pgd, pgd_k;
	357	pmd_t pmd, pmd_k;
	358
	359	pgd = tsk->active_mm->pgd + offset;
	360	pgd_k = init_mm.pgd + offset;
	361
	362	if (!pgd_present(*pgd)) {
	363	if (!pgd_present(*pgd_k))
	364	goto bad_area_nosemaphore;
	365	pgd_val(pgd) = pgd_val(pgd_k);
	366	return;
	367	}
	368
	369	pmd = pmd_offset(pgd, address);
	370	pmd_k = pmd_offset(pgd_k, address);
	371
	372	if (pmd_present(pmd) \|\| !pmd_present(pmd_k))
	373	goto bad_area_nosemaphore;
70168dfa	374
1da177e4 LT	375	pmd = pmd_k;
	376	return;
	377	}
	378	}
	379
1da177e4	380	/* This always deals with user addresses. */
50215d65	381	static void force_user_fault(unsigned long address, int write)
1da177e4 LT	382	{
	383	struct vm_area_struct *vma;
	384	struct task_struct *tsk = current;
	385	struct mm_struct *mm = tsk->mm;
4b177647	386	int code;
1da177e4	387
4b177647	388	code = SEGV_MAPERR;
1da177e4	389
1da177e4 LT	390	down_read(&mm->mmap_sem);
1da177e4 LT	391	vma = find_vma(mm, address);
70168dfa	392	if (!vma)
1da177e4	393	goto bad_area;
70168dfa	394	if (vma->vm_start <= address)
1da177e4	395	goto good_area;
70168dfa	396	if (!(vma->vm_flags & VM_GROWSDOWN))
1da177e4	397	goto bad_area;
70168dfa	398	if (expand_stack(vma, address))
1da177e4 LT	399	goto bad_area;
1da177e4 LT	400	good_area:
4b177647	401	code = SEGV_ACCERR;
70168dfa SR	402	if (write) {
70168dfa SR	403	if (!(vma->vm_flags & VM_WRITE))
1da177e4 LT	404	goto bad_area;
1da177e4 LT	405	} else {
70168dfa	406	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
1da177e4 LT	407	goto bad_area;
1da177e4 LT	408	}
d06063cc	409	switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
1da177e4 LT	410	case VM_FAULT_SIGBUS:
	411	case VM_FAULT_OOM:
	412	goto do_sigbus;
	413	}
	414	up_read(&mm->mmap_sem);
	415	return;
	416	bad_area:
	417	up_read(&mm->mmap_sem);
4b177647	418	__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
1da177e4 LT	419	return;
	420
	421	do_sigbus:
	422	up_read(&mm->mmap_sem);
4b177647	423	__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
1da177e4 LT	424	}
1da177e4 LT	425
9088333e DM	426	static void check_stack_aligned(unsigned long sp)
	427	{
	428	if (sp & 0x7UL)
	429	force_sig(SIGILL, current);
	430	}
	431
1da177e4 LT	432	void window_overflow_fault(void)
	433	{
	434	unsigned long sp;
	435
	436	sp = current_thread_info()->rwbuf_stkptrs[0];
70168dfa	437	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
1da177e4 LT	438	force_user_fault(sp + 0x38, 1);
1da177e4 LT	439	force_user_fault(sp, 1);
9088333e DM	440
9088333e DM	441	check_stack_aligned(sp);
1da177e4 LT	442	}
	443
	444	void window_underflow_fault(unsigned long sp)
	445	{
70168dfa	446	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
1da177e4 LT	447	force_user_fault(sp + 0x38, 0);
1da177e4 LT	448	force_user_fault(sp, 0);
9088333e DM	449
9088333e DM	450	check_stack_aligned(sp);
1da177e4 LT	451	}
	452
	453	void window_ret_fault(struct pt_regs *regs)
	454	{
	455	unsigned long sp;
	456
	457	sp = regs->u_regs[UREG_FP];
70168dfa	458	if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
1da177e4 LT	459	force_user_fault(sp + 0x38, 0);
1da177e4 LT	460	force_user_fault(sp, 0);
9088333e DM	461
9088333e DM	462	check_stack_aligned(sp);
1da177e4	463	}