[GitHub/mt8127/android_kernel_alcatel_ttab.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 <linux/kallsyms.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>
#include <asm/mmu_context.h>

#ifdef CONFIG_KPROBES
ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);

/* Hook to register for page fault notifications */
int register_page_fault_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
}

int unregister_page_fault_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
}

static inline int notify_page_fault(enum die_val val, const char *str,
			struct pt_regs *regs, long err, int trap, int sig)
{
	struct die_args args = {
		.regs = regs,
		.str = str,
		.err = err,
		.trapnr = trap,
		.signr = sig
	};
	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
}
#else
static inline int notify_page_fault(enum die_val val, const char *str,
			struct pt_regs *regs, long err, int trap, int sig)
{
	return NOTIFY_DONE;
}
#endif

/*
 * 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 vaddr)
{
	unsigned long *ksp;

	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
	       regs->tpc);
	printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
	print_symbol("RPC: <%s>\n", regs->u_regs[15]);
	printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
	__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, mm_rss;

	fault_code = get_thread_fault_code();

	if (notify_page_fault(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, address);
			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;
		/* All loads, stores and atomics have bits 30 and 31 both set
		 * in the instruction.  Bit 21 is set in all stores, but we
		 * have to avoid prefetches which also have bit 21 set.
		 */
		if ((insn & 0xc0200000) == 0xc0200000 &&
		    (insn & 0x01780000) != 0x01680000) {
			/* 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);

	mm_rss = get_mm_rss(mm);
#ifdef CONFIG_HUGETLB_PAGE
	mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
#endif
	if (unlikely(mm_rss >
		     mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
		tsb_grow(mm, MM_TSB_BASE, mm_rss);
#ifdef CONFIG_HUGETLB_PAGE
	mm_rss = mm->context.huge_pte_count;
	if (unlikely(mm_rss >
		     mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit))
		tsb_grow(mm, MM_TSB_HUGE, mm_rss);
#endif
	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>
eb398d10	22	#include <linux/kallsyms.h>
1da177e4 LT	23
	24	#include <asm/page.h>
	25	#include <asm/pgtable.h>
	26	#include <asm/openprom.h>
	27	#include <asm/oplib.h>
	28	#include <asm/uaccess.h>
	29	#include <asm/asi.h>
	30	#include <asm/lsu.h>
	31	#include <asm/sections.h>
	32	#include <asm/kdebug.h>
7a1ac526	33	#include <asm/mmu_context.h>
1da177e4	34
d98f8f05 AK	35	#ifdef CONFIG_KPROBES
	36	ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
	37
	38	/* Hook to register for page fault notifications */
	39	int register_page_fault_notifier(struct notifier_block *nb)
	40	{
	41	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
	42	}
	43
	44	int unregister_page_fault_notifier(struct notifier_block *nb)
	45	{
	46	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
	47	}
	48
	49	static inline int notify_page_fault(enum die_val val, const char *str,
	50	struct pt_regs *regs, long err, int trap, int sig)
	51	{
	52	struct die_args args = {
	53	.regs = regs,
	54	.str = str,
	55	.err = err,
	56	.trapnr = trap,
	57	.signr = sig
	58	};
	59	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
	60	}
	61	#else
	62	static inline int notify_page_fault(enum die_val val, const char *str,
	63	struct pt_regs *regs, long err, int trap, int sig)
	64	{
	65	return NOTIFY_DONE;
	66	}
	67	#endif
	68
1da177e4 LT	69	/*
	70	* To debug kernel to catch accesses to certain virtual/physical addresses.
	71	* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
	72	* flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
	73	* Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
	74	* watched. This is only useful on a single cpu machine for now. After the watchpoint
	75	* is detected, the process causing it will be killed, thus preventing an infinite loop.
	76	*/
	77	void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
	78	{
	79	unsigned long lsubits;
	80
	81	__asm__ __volatile__("ldxa [%%g0] %1, %0"
	82	: "=r" (lsubits)
	83	: "i" (ASI_LSU_CONTROL));
	84	lsubits &= ~(LSU_CONTROL_PM \| LSU_CONTROL_VM \|
	85	LSU_CONTROL_PR \| LSU_CONTROL_VR \|
	86	LSU_CONTROL_PW \| LSU_CONTROL_VW);
	87
	88	__asm__ __volatile__("stxa %0, [%1] %2\n\t"
	89	"membar #Sync"
	90	: /* no outputs */
	91	: "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
	92	"i" (ASI_DMMU));
	93
	94	lsubits \|= ((unsigned long)mask << (mode ? 25 : 33));
	95	if (flags & VM_READ)
	96	lsubits \|= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
	97	if (flags & VM_WRITE)
	98	lsubits \|= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
	99	__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
	100	"membar #Sync"
	101	: /* no outputs */
	102	: "r" (lsubits), "i" (ASI_LSU_CONTROL)
	103	: "memory");
	104	}
	105
05e14cb3 PP	106	static void __kprobes unhandled_fault(unsigned long address,
	107	struct task_struct *tsk,
	108	struct pt_regs *regs)
1da177e4 LT	109	{
	110	if ((unsigned long) address < PAGE_SIZE) {
	111	printk(KERN_ALERT "Unable to handle kernel NULL "
	112	"pointer dereference\n");
	113	} else {
	114	printk(KERN_ALERT "Unable to handle kernel paging request "
	115	"at virtual address %016lx\n", (unsigned long)address);
	116	}
	117	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
	118	(tsk->mm ?
	119	CTX_HWBITS(tsk->mm->context) :
	120	CTX_HWBITS(tsk->active_mm->context)));
	121	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
	122	(tsk->mm ? (unsigned long) tsk->mm->pgd :
	123	(unsigned long) tsk->active_mm->pgd));
	124	if (notify_die(DIE_GPF, "general protection fault", regs,
	125	0, 0, SIGSEGV) == NOTIFY_STOP)
	126	return;
	127	die_if_kernel("Oops", regs);
	128	}
	129
bf941d6c	130	static void bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
1da177e4 LT	131	{
	132	unsigned long *ksp;
	133
	134	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
	135	regs->tpc);
eb398d10 DM	136	printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
eb398d10 DM	137	print_symbol("RPC: <%s>\n", regs->u_regs[15]);
bf941d6c	138	printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
1da177e4 LT	139	__asm__("mov %%sp, %0" : "=r" (ksp));
	140	show_stack(current, ksp);
	141	unhandled_fault(regs->tpc, current, regs);
	142	}
	143
	144	/*
	145	* We now make sure that mmap_sem is held in all paths that call
	146	* this. Additionally, to prevent kswapd from ripping ptes from
	147	* under us, raise interrupts around the time that we look at the
	148	* pte, kswapd will have to wait to get his smp ipi response from
da160546	149	* us. vmtruncate likewise. This saves us having to get pte lock.
1da177e4 LT	150	*/
	151	static unsigned int get_user_insn(unsigned long tpc)
	152	{
	153	pgd_t *pgdp = pgd_offset(current->mm, tpc);
	154	pud_t *pudp;
	155	pmd_t *pmdp;
	156	pte_t *ptep, pte;
	157	unsigned long pa;
	158	u32 insn = 0;
	159	unsigned long pstate;
	160
	161	if (pgd_none(*pgdp))
	162	goto outret;
	163	pudp = pud_offset(pgdp, tpc);
	164	if (pud_none(*pudp))
	165	goto outret;
	166	pmdp = pmd_offset(pudp, tpc);
	167	if (pmd_none(*pmdp))
	168	goto outret;
	169
	170	/* This disables preemption for us as well. */
	171	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	172	__asm__ __volatile__("wrpr %0, %1, %%pstate"
	173	: : "r" (pstate), "i" (PSTATE_IE));
	174	ptep = pte_offset_map(pmdp, tpc);
	175	pte = *ptep;
	176	if (!pte_present(pte))
	177	goto out;
	178
c4bce90e	179	pa = (pte_pfn(pte) << PAGE_SHIFT);
1da177e4 LT	180	pa += (tpc & ~PAGE_MASK);
	181
	182	/* Use phys bypass so we don't pollute dtlb/dcache. */
	183	__asm__ __volatile__("lduwa [%1] %2, %0"
	184	: "=r" (insn)
	185	: "r" (pa), "i" (ASI_PHYS_USE_EC));
	186
	187	out:
	188	pte_unmap(ptep);
	189	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
	190	outret:
	191	return insn;
	192	}
	193
	194	extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
	195
	196	static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	197	unsigned int insn, int fault_code)
	198	{
	199	siginfo_t info;
	200
	201	info.si_code = code;
	202	info.si_signo = sig;
	203	info.si_errno = 0;
	204	if (fault_code & FAULT_CODE_ITLB)
	205	info.si_addr = (void __user *) regs->tpc;
	206	else
	207	info.si_addr = (void __user *)
	208	compute_effective_address(regs, insn, 0);
	209	info.si_trapno = 0;
	210	force_sig_info(sig, &info, current);
	211	}
	212
	213	extern int handle_ldf_stq(u32, struct pt_regs *);
	214	extern int handle_ld_nf(u32, struct pt_regs *);
	215
	216	static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
	217	{
	218	if (!insn) {
	219	if (!regs->tpc \|\| (regs->tpc & 0x3))
	220	return 0;
	221	if (regs->tstate & TSTATE_PRIV) {
	222	insn = (unsigned int ) regs->tpc;
	223	} else {
	224	insn = get_user_insn(regs->tpc);
	225	}
	226	}
	227	return insn;
	228	}
	229
	230	static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
	231	unsigned int insn, unsigned long address)
	232	{
1da177e4 LT	233	unsigned char asi = ASI_P;
	234
	235	if ((!insn) && (regs->tstate & TSTATE_PRIV))
	236	goto cannot_handle;
	237
	238	/* If user insn could be read (thus insn is zero), that
	239	* is fine. We will just gun down the process with a signal
	240	* in that case.
	241	*/
	242
	243	if (!(fault_code & (FAULT_CODE_WRITE\|FAULT_CODE_ITLB)) &&
	244	(insn & 0xc0800000) == 0xc0800000) {
	245	if (insn & 0x2000)
	246	asi = (regs->tstate >> 24);
	247	else
	248	asi = (insn >> 5);
	249	if ((asi & 0xf2) == 0x82) {
	250	if (insn & 0x1000000) {
	251	handle_ldf_stq(insn, regs);
	252	} else {
	253	/* This was a non-faulting load. Just clear the
	254	* destination register(s) and continue with the next
	255	* instruction. -jj
	256	*/
	257	handle_ld_nf(insn, regs);
	258	}
	259	return;
	260	}
	261	}
	262
1da177e4 LT	263	/* Is this in ex_table? */
1da177e4 LT	264	if (regs->tstate & TSTATE_PRIV) {
8cf14af0	265	const struct exception_table_entry *entry;
1da177e4 LT	266
	267	if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
	268	if (insn & 0x2000)
	269	asi = (regs->tstate >> 24);
	270	else
	271	asi = (insn >> 5);
	272	}
	273
	274	/* Look in asi.h: All _S asis have LS bit set */
	275	if ((asi & 0x1) &&
8cf14af0 DM	276	(entry = search_exception_tables(regs->tpc))) {
8cf14af0 DM	277	regs->tpc = entry->fixup;
1da177e4	278	regs->tnpc = regs->tpc + 4;
1da177e4 LT	279	return;
	280	}
	281	} else {
	282	/* The si_code was set to make clear whether
	283	* this was a SEGV_MAPERR or SEGV_ACCERR fault.
	284	*/
	285	do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
	286	return;
	287	}
	288
	289	cannot_handle:
	290	unhandled_fault (address, current, regs);
	291	}
	292
05e14cb3	293	asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
1da177e4 LT	294	{
	295	struct mm_struct *mm = current->mm;
	296	struct vm_area_struct *vma;
	297	unsigned int insn = 0;
	298	int si_code, fault_code;
7a1ac526	299	unsigned long address, mm_rss;
1da177e4 LT	300
	301	fault_code = get_thread_fault_code();
	302
d98f8f05	303	if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs,
1da177e4 LT	304	fault_code, 0, SIGSEGV) == NOTIFY_STOP)
	305	return;
	306
	307	si_code = SEGV_MAPERR;
	308	address = current_thread_info()->fault_address;
	309
	310	if ((fault_code & FAULT_CODE_ITLB) &&
	311	(fault_code & FAULT_CODE_DTLB))
	312	BUG();
	313
	314	if (regs->tstate & TSTATE_PRIV) {
	315	unsigned long tpc = regs->tpc;
	316
	317	/* Sanity check the PC. */
	318	if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) \|\|
	319	(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
	320	/* Valid, no problems... */
	321	} else {
bf941d6c	322	bad_kernel_pc(regs, address);
1da177e4 LT	323	return;
	324	}
	325	}
	326
	327	/*
	328	* If we're in an interrupt or have no user
	329	* context, we must not take the fault..
	330	*/
	331	if (in_atomic() \|\| !mm)
	332	goto intr_or_no_mm;
	333
	334	if (test_thread_flag(TIF_32BIT)) {
	335	if (!(regs->tstate & TSTATE_PRIV))
	336	regs->tpc &= 0xffffffff;
	337	address &= 0xffffffff;
	338	}
	339
	340	if (!down_read_trylock(&mm->mmap_sem)) {
	341	if ((regs->tstate & TSTATE_PRIV) &&
	342	!search_exception_tables(regs->tpc)) {
	343	insn = get_fault_insn(regs, insn);
	344	goto handle_kernel_fault;
	345	}
	346	down_read(&mm->mmap_sem);
	347	}
	348
	349	vma = find_vma(mm, address);
	350	if (!vma)
	351	goto bad_area;
	352
	353	/* Pure DTLB misses do not tell us whether the fault causing
	354	* load/store/atomic was a write or not, it only says that there
	355	* was no match. So in such a case we (carefully) read the
	356	* instruction to try and figure this out. It's an optimization
	357	* so it's ok if we can't do this.
	358	*
	359	* Special hack, window spill/fill knows the exact fault type.
	360	*/
	361	if (((fault_code &
	362	(FAULT_CODE_DTLB \| FAULT_CODE_WRITE \| FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
	363	(vma->vm_flags & VM_WRITE) != 0) {
	364	insn = get_fault_insn(regs, 0);
	365	if (!insn)
	366	goto continue_fault;
73c50a27 DM	367	/* All loads, stores and atomics have bits 30 and 31 both set
	368	* in the instruction. Bit 21 is set in all stores, but we
	369	* have to avoid prefetches which also have bit 21 set.
	370	*/
1da177e4	371	if ((insn & 0xc0200000) == 0xc0200000 &&
73c50a27	372	(insn & 0x01780000) != 0x01680000) {
1da177e4 LT	373	/* Don't bother updating thread struct value,
	374	* because update_mmu_cache only cares which tlb
	375	* the access came from.
	376	*/
	377	fault_code \|= FAULT_CODE_WRITE;
	378	}
	379	}
	380	continue_fault:
	381
	382	if (vma->vm_start <= address)
	383	goto good_area;
	384	if (!(vma->vm_flags & VM_GROWSDOWN))
	385	goto bad_area;
	386	if (!(fault_code & FAULT_CODE_WRITE)) {
	387	/* Non-faulting loads shouldn't expand stack. */
	388	insn = get_fault_insn(regs, insn);
	389	if ((insn & 0xc0800000) == 0xc0800000) {
	390	unsigned char asi;
	391
	392	if (insn & 0x2000)
	393	asi = (regs->tstate >> 24);
	394	else
	395	asi = (insn >> 5);
	396	if ((asi & 0xf2) == 0x82)
	397	goto bad_area;
	398	}
	399	}
	400	if (expand_stack(vma, address))
	401	goto bad_area;
	402	/*
	403	* Ok, we have a good vm_area for this memory access, so
	404	* we can handle it..
	405	*/
	406	good_area:
	407	si_code = SEGV_ACCERR;
	408
	409	/* If we took a ITLB miss on a non-executable page, catch
	410	* that here.
	411	*/
	412	if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
	413	BUG_ON(address != regs->tpc);
	414	BUG_ON(regs->tstate & TSTATE_PRIV);
	415	goto bad_area;
	416	}
	417
	418	if (fault_code & FAULT_CODE_WRITE) {
	419	if (!(vma->vm_flags & VM_WRITE))
	420	goto bad_area;
	421
	422	/* Spitfire has an icache which does not snoop
	423	* processor stores. Later processors do...
	424	*/
	425	if (tlb_type == spitfire &&
	426	(vma->vm_flags & VM_EXEC) != 0 &&
	427	vma->vm_file != NULL)
	428	set_thread_fault_code(fault_code \|
	429	FAULT_CODE_BLKCOMMIT);
	430	} else {
	431	/* Allow reads even for write-only mappings */
	432	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	433	goto bad_area;
	434	}
	435
	436	switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) {
437	case VM_FAULT_MINOR:
438	current->min_flt++;
439	break;
440	case VM_FAULT_MAJOR:
441	current->maj_flt++;
442	break;
443	case VM_FAULT_SIGBUS:
444	goto do_sigbus;
445	case VM_FAULT_OOM:
446	goto out_of_memory;
447	default:
448	BUG();
449	}
450
451	up_read(&mm->mmap_sem);
7a1ac526 DM	452
7a1ac526 DM	453	mm_rss = get_mm_rss(mm);
dcc1e8dd DM	454	#ifdef CONFIG_HUGETLB_PAGE
	455	mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
	456	#endif
7bebd83d	457	if (unlikely(mm_rss >
dcc1e8dd DM	458	mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
	459	tsb_grow(mm, MM_TSB_BASE, mm_rss);
	460	#ifdef CONFIG_HUGETLB_PAGE
	461	mm_rss = mm->context.huge_pte_count;
7bebd83d	462	if (unlikely(mm_rss >
dcc1e8dd DM	463	mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit))
	464	tsb_grow(mm, MM_TSB_HUGE, mm_rss);
	465	#endif
efdc1e20	466	return;
1da177e4 LT	467
	468	/*
	469	* Something tried to access memory that isn't in our memory map..
	470	* Fix it, but check if it's kernel or user first..
	471	*/
	472	bad_area:
	473	insn = get_fault_insn(regs, insn);
	474	up_read(&mm->mmap_sem);
	475
	476	handle_kernel_fault:
	477	do_kernel_fault(regs, si_code, fault_code, insn, address);
efdc1e20	478	return;
1da177e4 LT	479
	480	/*
	481	* We ran out of memory, or some other thing happened to us that made
	482	* us unable to handle the page fault gracefully.
	483	*/
	484	out_of_memory:
	485	insn = get_fault_insn(regs, insn);
	486	up_read(&mm->mmap_sem);
	487	printk("VM: killing process %s\n", current->comm);
	488	if (!(regs->tstate & TSTATE_PRIV))
	489	do_exit(SIGKILL);
	490	goto handle_kernel_fault;
	491
	492	intr_or_no_mm:
	493	insn = get_fault_insn(regs, 0);
	494	goto handle_kernel_fault;
	495
	496	do_sigbus:
	497	insn = get_fault_insn(regs, insn);
	498	up_read(&mm->mmap_sem);
	499
	500	/*
	501	* Send a sigbus, regardless of whether we were in kernel
	502	* or user mode.
	503	*/
	504	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
	505
	506	/* Kernel mode? Handle exceptions or die */
	507	if (regs->tstate & TSTATE_PRIV)
	508	goto handle_kernel_fault;
1da177e4	509	}