[deliverable/linux.git] / arch / sparc64 / mm / fault.c

/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
 * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.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/signal.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kprobes.h>

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>
#include <asm/asi.h>
#include <asm/lsu.h>
#include <asm/sections.h>
#include <asm/kdebug.h>

/*
 * To debug kernel to catch accesses to certain virtual/physical addresses.
 * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
 * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
 * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
 * watched. This is only useful on a single cpu machine for now. After the watchpoint
 * is detected, the process causing it will be killed, thus preventing an infinite loop.
 */
void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
{
	unsigned long lsubits;

	__asm__ __volatile__("ldxa [%%g0] %1, %0"
			     : "=r" (lsubits)
			     : "i" (ASI_LSU_CONTROL));
	lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM |
		     LSU_CONTROL_PR | LSU_CONTROL_VR |
		     LSU_CONTROL_PW | LSU_CONTROL_VW);

	__asm__ __volatile__("stxa	%0, [%1] %2\n\t"
			     "membar	#Sync"
			     : /* no outputs */
			     : "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
			       "i" (ASI_DMMU));

	lsubits |= ((unsigned long)mask << (mode ? 25 : 33));
	if (flags & VM_READ)
		lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
	if (flags & VM_WRITE)
		lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
	__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
			     "membar #Sync"
			     : /* no outputs */
			     : "r" (lsubits), "i" (ASI_LSU_CONTROL)
			     : "memory");
}

static void __kprobes 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 %016lx\n", (unsigned long)address);
	}
	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
	       (tsk->mm ?
		CTX_HWBITS(tsk->mm->context) :
		CTX_HWBITS(tsk->active_mm->context)));
	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
	       (tsk->mm ? (unsigned long) tsk->mm->pgd :
		          (unsigned long) tsk->active_mm->pgd));
	if (notify_die(DIE_GPF, "general protection fault", regs,
		       0, 0, SIGSEGV) == NOTIFY_STOP)
		return;
	die_if_kernel("Oops", regs);
}

static void bad_kernel_pc(struct pt_regs *regs)
{
	unsigned long *ksp;

	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
	       regs->tpc);
	__asm__("mov %%sp, %0" : "=r" (ksp));
	show_stack(current, ksp);
	unhandled_fault(regs->tpc, current, regs);
}

/*
 * We now make sure that mmap_sem is held in all paths that call 
 * this. Additionally, to prevent kswapd from ripping ptes from
 * under us, raise interrupts around the time that we look at the
 * pte, kswapd will have to wait to get his smp ipi response from
 * us. vmtruncate likewise. This saves us having to get pte lock.
 */
static unsigned int get_user_insn(unsigned long tpc)
{
	pgd_t *pgdp = pgd_offset(current->mm, tpc);
	pud_t *pudp;
	pmd_t *pmdp;
	pte_t *ptep, pte;
	unsigned long pa;
	u32 insn = 0;
	unsigned long pstate;

	if (pgd_none(*pgdp))
		goto outret;
	pudp = pud_offset(pgdp, tpc);
	if (pud_none(*pudp))
		goto outret;
	pmdp = pmd_offset(pudp, tpc);
	if (pmd_none(*pmdp))
		goto outret;

	/* This disables preemption for us as well. */
	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	__asm__ __volatile__("wrpr %0, %1, %%pstate"
				: : "r" (pstate), "i" (PSTATE_IE));
	ptep = pte_offset_map(pmdp, tpc);
	pte = *ptep;
	if (!pte_present(pte))
		goto out;

	pa  = (pte_pfn(pte) << PAGE_SHIFT);
	pa += (tpc & ~PAGE_MASK);

	/* Use phys bypass so we don't pollute dtlb/dcache. */
	__asm__ __volatile__("lduwa [%1] %2, %0"
			     : "=r" (insn)
			     : "r" (pa), "i" (ASI_PHYS_USE_EC));

out:
	pte_unmap(ptep);
	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
outret:
	return insn;
}

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

static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
			     unsigned int insn, int fault_code)
{
	siginfo_t info;

	info.si_code = code;
	info.si_signo = sig;
	info.si_errno = 0;
	if (fault_code & FAULT_CODE_ITLB)
		info.si_addr = (void __user *) regs->tpc;
	else
		info.si_addr = (void __user *)
			compute_effective_address(regs, insn, 0);
	info.si_trapno = 0;
	force_sig_info(sig, &info, current);
}

extern int handle_ldf_stq(u32, struct pt_regs *);
extern int handle_ld_nf(u32, struct pt_regs *);

static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
{
	if (!insn) {
		if (!regs->tpc || (regs->tpc & 0x3))
			return 0;
		if (regs->tstate & TSTATE_PRIV) {
			insn = *(unsigned int *) regs->tpc;
		} else {
			insn = get_user_insn(regs->tpc);
		}
	}
	return insn;
}

static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
			    unsigned int insn, unsigned long address)
{
	unsigned char asi = ASI_P;
 
	if ((!insn) && (regs->tstate & TSTATE_PRIV))
		goto cannot_handle;

	/* If user insn could be read (thus insn is zero), that
	 * is fine.  We will just gun down the process with a signal
	 * in that case.
	 */

	if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
	    (insn & 0xc0800000) == 0xc0800000) {
		if (insn & 0x2000)
			asi = (regs->tstate >> 24);
		else
			asi = (insn >> 5);
		if ((asi & 0xf2) == 0x82) {
			if (insn & 0x1000000) {
				handle_ldf_stq(insn, regs);
			} else {
				/* This was a non-faulting load. Just clear the
				 * destination register(s) and continue with the next
				 * instruction. -jj
				 */
				handle_ld_nf(insn, regs);
			}
			return;
		}
	}
		
	/* Is this in ex_table? */
	if (regs->tstate & TSTATE_PRIV) {
		const struct exception_table_entry *entry;

		if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
			if (insn & 0x2000)
				asi = (regs->tstate >> 24);
			else
				asi = (insn >> 5);
		}
	
		/* Look in asi.h: All _S asis have LS bit set */
		if ((asi & 0x1) &&
		    (entry = search_exception_tables(regs->tpc))) {
			regs->tpc = entry->fixup;
			regs->tnpc = regs->tpc + 4;
			return;
		}
	} else {
		/* The si_code was set to make clear whether
		 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
		 */
		do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
		return;
	}

cannot_handle:
	unhandled_fault (address, current, regs);
}

asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned int insn = 0;
	int si_code, fault_code;
	unsigned long address;

	fault_code = get_thread_fault_code();

	if (notify_die(DIE_PAGE_FAULT, "page_fault", regs,
		       fault_code, 0, SIGSEGV) == NOTIFY_STOP)
		return;

	si_code = SEGV_MAPERR;
	address = current_thread_info()->fault_address;

	if ((fault_code & FAULT_CODE_ITLB) &&
	    (fault_code & FAULT_CODE_DTLB))
		BUG();

	if (regs->tstate & TSTATE_PRIV) {
		unsigned long tpc = regs->tpc;

		/* Sanity check the PC. */
		if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) ||
		    (tpc >= MODULES_VADDR && tpc < MODULES_END)) {
			/* Valid, no problems... */
		} else {
			bad_kernel_pc(regs);
			return;
		}
	}

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

	if (test_thread_flag(TIF_32BIT)) {
		if (!(regs->tstate & TSTATE_PRIV))
			regs->tpc &= 0xffffffff;
		address &= 0xffffffff;
	}

	if (!down_read_trylock(&mm->mmap_sem)) {
		if ((regs->tstate & TSTATE_PRIV) &&
		    !search_exception_tables(regs->tpc)) {
			insn = get_fault_insn(regs, insn);
			goto handle_kernel_fault;
		}
		down_read(&mm->mmap_sem);
	}

	vma = find_vma(mm, address);
	if (!vma)
		goto bad_area;

	/* Pure DTLB misses do not tell us whether the fault causing
	 * load/store/atomic was a write or not, it only says that there
	 * was no match.  So in such a case we (carefully) read the
	 * instruction to try and figure this out.  It's an optimization
	 * so it's ok if we can't do this.
	 *
	 * Special hack, window spill/fill knows the exact fault type.
	 */
	if (((fault_code &
	      (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
	    (vma->vm_flags & VM_WRITE) != 0) {
		insn = get_fault_insn(regs, 0);
		if (!insn)
			goto continue_fault;
		if ((insn & 0xc0200000) == 0xc0200000 &&
		    (insn & 0x1780000) != 0x1680000) {
			/* Don't bother updating thread struct value,
			 * because update_mmu_cache only cares which tlb
			 * the access came from.
			 */
			fault_code |= FAULT_CODE_WRITE;
		}
	}
continue_fault:

	if (vma->vm_start <= address)
		goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
		goto bad_area;
	if (!(fault_code & FAULT_CODE_WRITE)) {
		/* Non-faulting loads shouldn't expand stack. */
		insn = get_fault_insn(regs, insn);
		if ((insn & 0xc0800000) == 0xc0800000) {
			unsigned char asi;

			if (insn & 0x2000)
				asi = (regs->tstate >> 24);
			else
				asi = (insn >> 5);
			if ((asi & 0xf2) == 0x82)
				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:
	si_code = SEGV_ACCERR;

	/* If we took a ITLB miss on a non-executable page, catch
	 * that here.
	 */
	if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
		BUG_ON(address != regs->tpc);
		BUG_ON(regs->tstate & TSTATE_PRIV);
		goto bad_area;
	}

	if (fault_code & FAULT_CODE_WRITE) {
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;

		/* Spitfire has an icache which does not snoop
		 * processor stores.  Later processors do...
		 */
		if (tlb_type == spitfire &&
		    (vma->vm_flags & VM_EXEC) != 0 &&
		    vma->vm_file != NULL)
			set_thread_fault_code(fault_code |
					      FAULT_CODE_BLKCOMMIT);
	} else {
		/* Allow reads even for write-only mappings */
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto bad_area;
	}

	switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) {
	case VM_FAULT_MINOR:
		current->min_flt++;
		break;
	case VM_FAULT_MAJOR:
		current->maj_flt++;
		break;
	case VM_FAULT_SIGBUS:
		goto do_sigbus;
	case VM_FAULT_OOM:
		goto out_of_memory;
	default:
		BUG();
	}

	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:
	insn = get_fault_insn(regs, insn);
	up_read(&mm->mmap_sem);

handle_kernel_fault:
	do_kernel_fault(regs, si_code, fault_code, insn, address);
	return;

/*
 * 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:
	insn = get_fault_insn(regs, insn);
	up_read(&mm->mmap_sem);
	printk("VM: killing process %s\n", current->comm);
	if (!(regs->tstate & TSTATE_PRIV))
		do_exit(SIGKILL);
	goto handle_kernel_fault;

intr_or_no_mm:
	insn = get_fault_insn(regs, 0);
	goto handle_kernel_fault;

do_sigbus:
	insn = get_fault_insn(regs, insn);
	up_read(&mm->mmap_sem);

	/*
	 * Send a sigbus, regardless of whether we were in kernel
	 * or user mode.
	 */
	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);

	/* Kernel mode? Handle exceptions or die */
	if (regs->tstate & TSTATE_PRIV)
		goto handle_kernel_fault;
}
Commit	Line	Data
1da177e4 LT	1	/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
	2	* arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
	3	*
	4	* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
	5	* Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
	6	*/
	7
	8	#include <asm/head.h>
	9
	10	#include <linux/string.h>
	11	#include <linux/types.h>
	12	#include <linux/sched.h>
	13	#include <linux/ptrace.h>
	14	#include <linux/mman.h>
	15	#include <linux/signal.h>
	16	#include <linux/mm.h>
	17	#include <linux/module.h>
	18	#include <linux/smp_lock.h>
	19	#include <linux/init.h>
	20	#include <linux/interrupt.h>
05e14cb3	21	#include <linux/kprobes.h>
1da177e4 LT	22
	23	#include <asm/page.h>
	24	#include <asm/pgtable.h>
	25	#include <asm/openprom.h>
	26	#include <asm/oplib.h>
	27	#include <asm/uaccess.h>
	28	#include <asm/asi.h>
	29	#include <asm/lsu.h>
	30	#include <asm/sections.h>
	31	#include <asm/kdebug.h>
	32
1da177e4 LT	33	/*
	34	* To debug kernel to catch accesses to certain virtual/physical addresses.
	35	* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
	36	* flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
	37	* Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
	38	* watched. This is only useful on a single cpu machine for now. After the watchpoint
	39	* is detected, the process causing it will be killed, thus preventing an infinite loop.
	40	*/
	41	void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
	42	{
	43	unsigned long lsubits;
	44
	45	__asm__ __volatile__("ldxa [%%g0] %1, %0"
	46	: "=r" (lsubits)
	47	: "i" (ASI_LSU_CONTROL));
	48	lsubits &= ~(LSU_CONTROL_PM \| LSU_CONTROL_VM \|
	49	LSU_CONTROL_PR \| LSU_CONTROL_VR \|
	50	LSU_CONTROL_PW \| LSU_CONTROL_VW);
	51
	52	__asm__ __volatile__("stxa %0, [%1] %2\n\t"
	53	"membar #Sync"
	54	: /* no outputs */
	55	: "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
	56	"i" (ASI_DMMU));
	57
	58	lsubits \|= ((unsigned long)mask << (mode ? 25 : 33));
	59	if (flags & VM_READ)
	60	lsubits \|= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
	61	if (flags & VM_WRITE)
	62	lsubits \|= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
	63	__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
	64	"membar #Sync"
	65	: /* no outputs */
	66	: "r" (lsubits), "i" (ASI_LSU_CONTROL)
	67	: "memory");
	68	}
	69
05e14cb3 PP	70	static void __kprobes unhandled_fault(unsigned long address,
	71	struct task_struct *tsk,
	72	struct pt_regs *regs)
1da177e4 LT	73	{
	74	if ((unsigned long) address < PAGE_SIZE) {
	75	printk(KERN_ALERT "Unable to handle kernel NULL "
	76	"pointer dereference\n");
	77	} else {
	78	printk(KERN_ALERT "Unable to handle kernel paging request "
	79	"at virtual address %016lx\n", (unsigned long)address);
	80	}
	81	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
	82	(tsk->mm ?
	83	CTX_HWBITS(tsk->mm->context) :
	84	CTX_HWBITS(tsk->active_mm->context)));
	85	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
	86	(tsk->mm ? (unsigned long) tsk->mm->pgd :
	87	(unsigned long) tsk->active_mm->pgd));
	88	if (notify_die(DIE_GPF, "general protection fault", regs,
	89	0, 0, SIGSEGV) == NOTIFY_STOP)
	90	return;
	91	die_if_kernel("Oops", regs);
	92	}
	93
	94	static void bad_kernel_pc(struct pt_regs *regs)
	95	{
	96	unsigned long *ksp;
	97
	98	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
	99	regs->tpc);
	100	__asm__("mov %%sp, %0" : "=r" (ksp));
	101	show_stack(current, ksp);
	102	unhandled_fault(regs->tpc, current, regs);
	103	}
	104
	105	/*
	106	* We now make sure that mmap_sem is held in all paths that call
	107	* this. Additionally, to prevent kswapd from ripping ptes from
	108	* under us, raise interrupts around the time that we look at the
	109	* pte, kswapd will have to wait to get his smp ipi response from
da160546	110	* us. vmtruncate likewise. This saves us having to get pte lock.
1da177e4 LT	111	*/
	112	static unsigned int get_user_insn(unsigned long tpc)
	113	{
	114	pgd_t *pgdp = pgd_offset(current->mm, tpc);
	115	pud_t *pudp;
	116	pmd_t *pmdp;
	117	pte_t *ptep, pte;
	118	unsigned long pa;
	119	u32 insn = 0;
	120	unsigned long pstate;
	121
	122	if (pgd_none(*pgdp))
	123	goto outret;
	124	pudp = pud_offset(pgdp, tpc);
	125	if (pud_none(*pudp))
	126	goto outret;
	127	pmdp = pmd_offset(pudp, tpc);
	128	if (pmd_none(*pmdp))
	129	goto outret;
	130
	131	/* This disables preemption for us as well. */
	132	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	133	__asm__ __volatile__("wrpr %0, %1, %%pstate"
	134	: : "r" (pstate), "i" (PSTATE_IE));
	135	ptep = pte_offset_map(pmdp, tpc);
	136	pte = *ptep;
	137	if (!pte_present(pte))
	138	goto out;
	139
c4bce90e	140	pa = (pte_pfn(pte) << PAGE_SHIFT);
1da177e4 LT	141	pa += (tpc & ~PAGE_MASK);
	142
	143	/* Use phys bypass so we don't pollute dtlb/dcache. */
	144	__asm__ __volatile__("lduwa [%1] %2, %0"
	145	: "=r" (insn)
	146	: "r" (pa), "i" (ASI_PHYS_USE_EC));
	147
	148	out:
	149	pte_unmap(ptep);
	150	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
	151	outret:
	152	return insn;
	153	}
	154
	155	extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
	156
	157	static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	158	unsigned int insn, int fault_code)
	159	{
	160	siginfo_t info;
	161
	162	info.si_code = code;
	163	info.si_signo = sig;
	164	info.si_errno = 0;
	165	if (fault_code & FAULT_CODE_ITLB)
	166	info.si_addr = (void __user *) regs->tpc;
	167	else
	168	info.si_addr = (void __user *)
	169	compute_effective_address(regs, insn, 0);
	170	info.si_trapno = 0;
	171	force_sig_info(sig, &info, current);
	172	}
	173
	174	extern int handle_ldf_stq(u32, struct pt_regs *);
	175	extern int handle_ld_nf(u32, struct pt_regs *);
	176
	177	static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
	178	{
	179	if (!insn) {
	180	if (!regs->tpc \|\| (regs->tpc & 0x3))
	181	return 0;
	182	if (regs->tstate & TSTATE_PRIV) {
	183	insn = (unsigned int ) regs->tpc;
	184	} else {
	185	insn = get_user_insn(regs->tpc);
	186	}
	187	}
	188	return insn;
	189	}
	190
	191	static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
	192	unsigned int insn, unsigned long address)
	193	{
1da177e4 LT	194	unsigned char asi = ASI_P;
	195
	196	if ((!insn) && (regs->tstate & TSTATE_PRIV))
	197	goto cannot_handle;
	198
	199	/* If user insn could be read (thus insn is zero), that
	200	* is fine. We will just gun down the process with a signal
	201	* in that case.
	202	*/
	203
	204	if (!(fault_code & (FAULT_CODE_WRITE\|FAULT_CODE_ITLB)) &&
	205	(insn & 0xc0800000) == 0xc0800000) {
	206	if (insn & 0x2000)
	207	asi = (regs->tstate >> 24);
	208	else
	209	asi = (insn >> 5);
	210	if ((asi & 0xf2) == 0x82) {
	211	if (insn & 0x1000000) {
	212	handle_ldf_stq(insn, regs);
	213	} else {
	214	/* This was a non-faulting load. Just clear the
	215	* destination register(s) and continue with the next
	216	* instruction. -jj
	217	*/
	218	handle_ld_nf(insn, regs);
	219	}
	220	return;
	221	}
	222	}
	223
1da177e4 LT	224	/* Is this in ex_table? */
1da177e4 LT	225	if (regs->tstate & TSTATE_PRIV) {
8cf14af0	226	const struct exception_table_entry *entry;
1da177e4 LT	227
	228	if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
	229	if (insn & 0x2000)
	230	asi = (regs->tstate >> 24);
	231	else
	232	asi = (insn >> 5);
	233	}
	234
	235	/* Look in asi.h: All _S asis have LS bit set */
	236	if ((asi & 0x1) &&
8cf14af0 DM	237	(entry = search_exception_tables(regs->tpc))) {
8cf14af0 DM	238	regs->tpc = entry->fixup;
1da177e4	239	regs->tnpc = regs->tpc + 4;
1da177e4 LT	240	return;
	241	}
	242	} else {
	243	/* The si_code was set to make clear whether
	244	* this was a SEGV_MAPERR or SEGV_ACCERR fault.
	245	*/
	246	do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
	247	return;
	248	}
	249
	250	cannot_handle:
	251	unhandled_fault (address, current, regs);
	252	}
	253
05e14cb3	254	asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
1da177e4 LT	255	{
	256	struct mm_struct *mm = current->mm;
	257	struct vm_area_struct *vma;
	258	unsigned int insn = 0;
	259	int si_code, fault_code;
	260	unsigned long address;
	261
	262	fault_code = get_thread_fault_code();
	263
	264	if (notify_die(DIE_PAGE_FAULT, "page_fault", regs,
	265	fault_code, 0, SIGSEGV) == NOTIFY_STOP)
	266	return;
	267
	268	si_code = SEGV_MAPERR;
	269	address = current_thread_info()->fault_address;
	270
	271	if ((fault_code & FAULT_CODE_ITLB) &&
	272	(fault_code & FAULT_CODE_DTLB))
	273	BUG();
	274
	275	if (regs->tstate & TSTATE_PRIV) {
	276	unsigned long tpc = regs->tpc;
	277
	278	/* Sanity check the PC. */
	279	if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) \|\|
	280	(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
	281	/* Valid, no problems... */
	282	} else {
	283	bad_kernel_pc(regs);
	284	return;
	285	}
	286	}
	287
	288	/*
	289	* If we're in an interrupt or have no user
	290	* context, we must not take the fault..
	291	*/
	292	if (in_atomic() \|\| !mm)
	293	goto intr_or_no_mm;
	294
	295	if (test_thread_flag(TIF_32BIT)) {
	296	if (!(regs->tstate & TSTATE_PRIV))
	297	regs->tpc &= 0xffffffff;
	298	address &= 0xffffffff;
	299	}
	300
	301	if (!down_read_trylock(&mm->mmap_sem)) {
	302	if ((regs->tstate & TSTATE_PRIV) &&
	303	!search_exception_tables(regs->tpc)) {
	304	insn = get_fault_insn(regs, insn);
	305	goto handle_kernel_fault;
	306	}
	307	down_read(&mm->mmap_sem);
	308	}
	309
	310	vma = find_vma(mm, address);
	311	if (!vma)
	312	goto bad_area;
	313
	314	/* Pure DTLB misses do not tell us whether the fault causing
	315	* load/store/atomic was a write or not, it only says that there
	316	* was no match. So in such a case we (carefully) read the
	317	* instruction to try and figure this out. It's an optimization
	318	* so it's ok if we can't do this.
319	*
320	* Special hack, window spill/fill knows the exact fault type.
321	*/
322	if (((fault_code &
323	(FAULT_CODE_DTLB \| FAULT_CODE_WRITE \| FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
324	(vma->vm_flags & VM_WRITE) != 0) {
325	insn = get_fault_insn(regs, 0);
326	if (!insn)
327	goto continue_fault;
328	if ((insn & 0xc0200000) == 0xc0200000 &&
329	(insn & 0x1780000) != 0x1680000) {
330	/* Don't bother updating thread struct value,
331	* because update_mmu_cache only cares which tlb
332	* the access came from.
333	*/
334	fault_code \|= FAULT_CODE_WRITE;
335	}
336	}
337	continue_fault:
338
339	if (vma->vm_start <= address)
340	goto good_area;
341	if (!(vma->vm_flags & VM_GROWSDOWN))
342	goto bad_area;
343	if (!(fault_code & FAULT_CODE_WRITE)) {
344	/* Non-faulting loads shouldn't expand stack. */
345	insn = get_fault_insn(regs, insn);
346	if ((insn & 0xc0800000) == 0xc0800000) {
347	unsigned char asi;
348
349	if (insn & 0x2000)
350	asi = (regs->tstate >> 24);
351	else
352	asi = (insn >> 5);
353	if ((asi & 0xf2) == 0x82)
354	goto bad_area;
355	}
356	}
357	if (expand_stack(vma, address))
358	goto bad_area;
359	/*
360	* Ok, we have a good vm_area for this memory access, so
361	* we can handle it..
362	*/
363	good_area:
364	si_code = SEGV_ACCERR;
365
366	/* If we took a ITLB miss on a non-executable page, catch
367	* that here.
368	*/
369	if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
370	BUG_ON(address != regs->tpc);
371	BUG_ON(regs->tstate & TSTATE_PRIV);
372	goto bad_area;
373	}
374
375	if (fault_code & FAULT_CODE_WRITE) {
376	if (!(vma->vm_flags & VM_WRITE))
377	goto bad_area;
378
379	/* Spitfire has an icache which does not snoop
380	* processor stores. Later processors do...
381	*/
382	if (tlb_type == spitfire &&
383	(vma->vm_flags & VM_EXEC) != 0 &&
384	vma->vm_file != NULL)
385	set_thread_fault_code(fault_code \|
386	FAULT_CODE_BLKCOMMIT);
387	} else {
388	/* Allow reads even for write-only mappings */
389	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
390	goto bad_area;
391	}
392
393	switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) {
394	case VM_FAULT_MINOR:
395	current->min_flt++;
396	break;
397	case VM_FAULT_MAJOR:
398	current->maj_flt++;
399	break;
400	case VM_FAULT_SIGBUS:
401	goto do_sigbus;
402	case VM_FAULT_OOM:
403	goto out_of_memory;
404	default:
405	BUG();
406	}
407
408	up_read(&mm->mmap_sem);
efdc1e20	409	return;
1da177e4 LT	410
	411	/*
	412	* Something tried to access memory that isn't in our memory map..
	413	* Fix it, but check if it's kernel or user first..
	414	*/
	415	bad_area:
	416	insn = get_fault_insn(regs, insn);
	417	up_read(&mm->mmap_sem);
	418
	419	handle_kernel_fault:
	420	do_kernel_fault(regs, si_code, fault_code, insn, address);
efdc1e20	421	return;
1da177e4 LT	422
	423	/*
	424	* We ran out of memory, or some other thing happened to us that made
	425	* us unable to handle the page fault gracefully.
	426	*/
	427	out_of_memory:
	428	insn = get_fault_insn(regs, insn);
	429	up_read(&mm->mmap_sem);
	430	printk("VM: killing process %s\n", current->comm);
	431	if (!(regs->tstate & TSTATE_PRIV))
	432	do_exit(SIGKILL);
	433	goto handle_kernel_fault;
	434
	435	intr_or_no_mm:
	436	insn = get_fault_insn(regs, 0);
	437	goto handle_kernel_fault;
	438
	439	do_sigbus:
	440	insn = get_fault_insn(regs, insn);
	441	up_read(&mm->mmap_sem);
	442
	443	/*
	444	* Send a sigbus, regardless of whether we were in kernel
	445	* or user mode.
	446	*/
	447	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
	448
	449	/* Kernel mode? Handle exceptions or die */
	450	if (regs->tstate & TSTATE_PRIV)
	451	goto handle_kernel_fault;
1da177e4	452	}