[deliverable/linux.git] / arch / sparc / mm / fault_64.c

/*
 * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
 *
 * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
 * 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/init.h>
#include <linux/interrupt.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/percpu.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/mmu_context.h>

#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs)
{
	int ret = 0;

	/* kprobe_running() needs smp_processor_id() */
	if (!user_mode(regs)) {
		preempt_disable();
		if (kprobe_running() && kprobe_fault_handler(regs, 0))
			ret = 1;
		preempt_enable();
	}
	return ret;
}
#else
static inline int notify_page_fault(struct pt_regs *regs)
{
	return 0;
}
#endif

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));
	die_if_kernel("Oops", regs);
}

static void bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
{
	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]);
	printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
	printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
	dump_stack();
	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;

		entry = search_exception_tables(regs->tpc);
		if (entry) {
			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);
}

static void noinline bogus_32bit_fault_tpc(struct pt_regs *regs)
{
	static int times;

	if (times++ < 10)
		printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
		       "64-bit TPC [%lx]\n",
		       current->comm, current->pid,
		       regs->tpc);
	show_regs(regs);
}

static void noinline bogus_32bit_fault_address(struct pt_regs *regs,
					       unsigned long addr)
{
	static int times;

	if (times++ < 10)
		printk(KERN_ERR "FAULT[%s:%d]: 32-bit process "
		       "reports 64-bit fault address [%lx]\n",
		       current->comm, current->pid, addr);
	show_regs(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, fault;
	unsigned long address, mm_rss;

	fault_code = get_thread_fault_code();

	if (notify_page_fault(regs))
		return;

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

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

	if (test_thread_flag(TIF_32BIT)) {
		if (!(regs->tstate & TSTATE_PRIV)) {
			if (unlikely((regs->tpc >> 32) != 0)) {
				bogus_32bit_fault_tpc(regs);
				goto intr_or_no_mm;
			}
		}
		if (unlikely((address >> 32) != 0)) {
			bogus_32bit_fault_address(regs, address);
			goto intr_or_no_mm;
		}
	}

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

		/* Sanity check the PC. */
		if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) ||
		    (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 (!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;
	}

	fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE) ? FAULT_FLAG_WRITE : 0);
	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 (fault & VM_FAULT_MAJOR)
		current->maj_flt++;
	else
		current->min_flt++;

	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_group_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
b00dc837	1	/*
1da177e4 LT	2	* arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
1da177e4 LT	3	*
4fe3ebec	4	* Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
1da177e4 LT	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>
1da177e4 LT	18	#include <linux/init.h>
1da177e4 LT	19	#include <linux/interrupt.h>
05e14cb3	20	#include <linux/kprobes.h>
1eeb66a1	21	#include <linux/kdebug.h>
eeabac73	22	#include <linux/percpu.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>
7a1ac526	32	#include <asm/mmu_context.h>
1da177e4	33
d98f8f05	34	#ifdef CONFIG_KPROBES
127cda1e	35	static inline int notify_page_fault(struct pt_regs *regs)
d98f8f05	36	{
127cda1e DM	37	int ret = 0;
	38
	39	/* kprobe_running() needs smp_processor_id() */
	40	if (!user_mode(regs)) {
	41	preempt_disable();
	42	if (kprobe_running() && kprobe_fault_handler(regs, 0))
	43	ret = 1;
	44	preempt_enable();
	45	}
	46	return ret;
d98f8f05 AK	47	}
d98f8f05 AK	48	#else
127cda1e	49	static inline int notify_page_fault(struct pt_regs *regs)
d98f8f05	50	{
127cda1e	51	return 0;
d98f8f05 AK	52	}
	53	#endif
	54
05e14cb3 PP	55	static void __kprobes unhandled_fault(unsigned long address,
	56	struct task_struct *tsk,
	57	struct pt_regs *regs)
1da177e4 LT	58	{
	59	if ((unsigned long) address < PAGE_SIZE) {
	60	printk(KERN_ALERT "Unable to handle kernel NULL "
	61	"pointer dereference\n");
	62	} else {
	63	printk(KERN_ALERT "Unable to handle kernel paging request "
	64	"at virtual address %016lx\n", (unsigned long)address);
	65	}
	66	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
	67	(tsk->mm ?
	68	CTX_HWBITS(tsk->mm->context) :
	69	CTX_HWBITS(tsk->active_mm->context)));
	70	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
	71	(tsk->mm ? (unsigned long) tsk->mm->pgd :
	72	(unsigned long) tsk->active_mm->pgd));
1da177e4 LT	73	die_if_kernel("Oops", regs);
	74	}
	75
bf941d6c	76	static void bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
1da177e4	77	{
1da177e4 LT	78	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
1da177e4 LT	79	regs->tpc);
eb398d10	80	printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
4fe3ebec	81	printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
bf941d6c	82	printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
c1f193a7	83	dump_stack();
1da177e4 LT	84	unhandled_fault(regs->tpc, current, regs);
	85	}
	86
	87	/*
	88	* We now make sure that mmap_sem is held in all paths that call
	89	* this. Additionally, to prevent kswapd from ripping ptes from
	90	* under us, raise interrupts around the time that we look at the
	91	* pte, kswapd will have to wait to get his smp ipi response from
da160546	92	* us. vmtruncate likewise. This saves us having to get pte lock.
1da177e4 LT	93	*/
	94	static unsigned int get_user_insn(unsigned long tpc)
	95	{
	96	pgd_t *pgdp = pgd_offset(current->mm, tpc);
	97	pud_t *pudp;
	98	pmd_t *pmdp;
	99	pte_t *ptep, pte;
	100	unsigned long pa;
	101	u32 insn = 0;
	102	unsigned long pstate;
	103
	104	if (pgd_none(*pgdp))
	105	goto outret;
	106	pudp = pud_offset(pgdp, tpc);
	107	if (pud_none(*pudp))
	108	goto outret;
	109	pmdp = pmd_offset(pudp, tpc);
	110	if (pmd_none(*pmdp))
	111	goto outret;
	112
	113	/* This disables preemption for us as well. */
	114	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	115	__asm__ __volatile__("wrpr %0, %1, %%pstate"
	116	: : "r" (pstate), "i" (PSTATE_IE));
	117	ptep = pte_offset_map(pmdp, tpc);
	118	pte = *ptep;
	119	if (!pte_present(pte))
	120	goto out;
	121
c4bce90e	122	pa = (pte_pfn(pte) << PAGE_SHIFT);
1da177e4 LT	123	pa += (tpc & ~PAGE_MASK);
	124
	125	/* Use phys bypass so we don't pollute dtlb/dcache. */
	126	__asm__ __volatile__("lduwa [%1] %2, %0"
	127	: "=r" (insn)
	128	: "r" (pa), "i" (ASI_PHYS_USE_EC));
	129
	130	out:
	131	pte_unmap(ptep);
	132	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
	133	outret:
	134	return insn;
	135	}
	136
	137	extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
	138
	139	static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	140	unsigned int insn, int fault_code)
	141	{
	142	siginfo_t info;
	143
	144	info.si_code = code;
	145	info.si_signo = sig;
	146	info.si_errno = 0;
	147	if (fault_code & FAULT_CODE_ITLB)
	148	info.si_addr = (void __user *) regs->tpc;
	149	else
	150	info.si_addr = (void __user *)
	151	compute_effective_address(regs, insn, 0);
	152	info.si_trapno = 0;
	153	force_sig_info(sig, &info, current);
	154	}
	155
	156	extern int handle_ldf_stq(u32, struct pt_regs *);
	157	extern int handle_ld_nf(u32, struct pt_regs *);
	158
	159	static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
	160	{
	161	if (!insn) {
	162	if (!regs->tpc \|\| (regs->tpc & 0x3))
	163	return 0;
	164	if (regs->tstate & TSTATE_PRIV) {
	165	insn = (unsigned int ) regs->tpc;
	166	} else {
	167	insn = get_user_insn(regs->tpc);
	168	}
	169	}
	170	return insn;
	171	}
	172
	173	static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
	174	unsigned int insn, unsigned long address)
	175	{
1da177e4 LT	176	unsigned char asi = ASI_P;
	177
	178	if ((!insn) && (regs->tstate & TSTATE_PRIV))
	179	goto cannot_handle;
	180
	181	/* If user insn could be read (thus insn is zero), that
	182	* is fine. We will just gun down the process with a signal
	183	* in that case.
	184	*/
	185
	186	if (!(fault_code & (FAULT_CODE_WRITE\|FAULT_CODE_ITLB)) &&
	187	(insn & 0xc0800000) == 0xc0800000) {
	188	if (insn & 0x2000)
	189	asi = (regs->tstate >> 24);
	190	else
	191	asi = (insn >> 5);
	192	if ((asi & 0xf2) == 0x82) {
	193	if (insn & 0x1000000) {
	194	handle_ldf_stq(insn, regs);
	195	} else {
	196	/* This was a non-faulting load. Just clear the
	197	* destination register(s) and continue with the next
	198	* instruction. -jj
	199	*/
	200	handle_ld_nf(insn, regs);
	201	}
	202	return;
	203	}
	204	}
	205
1da177e4 LT	206	/* Is this in ex_table? */
1da177e4 LT	207	if (regs->tstate & TSTATE_PRIV) {
8cf14af0	208	const struct exception_table_entry *entry;
1da177e4	209
622eaec6 DM	210	entry = search_exception_tables(regs->tpc);
622eaec6 DM	211	if (entry) {
8cf14af0	212	regs->tpc = entry->fixup;
1da177e4	213	regs->tnpc = regs->tpc + 4;
1da177e4 LT	214	return;
	215	}
	216	} else {
	217	/* The si_code was set to make clear whether
	218	* this was a SEGV_MAPERR or SEGV_ACCERR fault.
	219	*/
	220	do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
	221	return;
	222	}
	223
	224	cannot_handle:
	225	unhandled_fault (address, current, regs);
	226	}
	227
9b026058 DM	228	static void noinline bogus_32bit_fault_tpc(struct pt_regs *regs)
	229	{
	230	static int times;
	231
	232	if (times++ < 10)
	233	printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
	234	"64-bit TPC [%lx]\n",
	235	current->comm, current->pid,
	236	regs->tpc);
	237	show_regs(regs);
	238	}
	239
	240	static void noinline bogus_32bit_fault_address(struct pt_regs *regs,
	241	unsigned long addr)
	242	{
	243	static int times;
	244
	245	if (times++ < 10)
	246	printk(KERN_ERR "FAULT[%s:%d]: 32-bit process "
	247	"reports 64-bit fault address [%lx]\n",
	248	current->comm, current->pid, addr);
	249	show_regs(regs);
	250	}
	251
05e14cb3	252	asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
1da177e4 LT	253	{
	254	struct mm_struct *mm = current->mm;
	255	struct vm_area_struct *vma;
	256	unsigned int insn = 0;
83c54070	257	int si_code, fault_code, fault;
7a1ac526	258	unsigned long address, mm_rss;
1da177e4 LT	259
	260	fault_code = get_thread_fault_code();
	261
127cda1e	262	if (notify_page_fault(regs))
1da177e4 LT	263	return;
	264
	265	si_code = SEGV_MAPERR;
	266	address = current_thread_info()->fault_address;
	267
	268	if ((fault_code & FAULT_CODE_ITLB) &&
	269	(fault_code & FAULT_CODE_DTLB))
	270	BUG();
	271
eeabac73	272	if (test_thread_flag(TIF_32BIT)) {
9b026058 DM	273	if (!(regs->tstate & TSTATE_PRIV)) {
	274	if (unlikely((regs->tpc >> 32) != 0)) {
	275	bogus_32bit_fault_tpc(regs);
	276	goto intr_or_no_mm;
	277	}
	278	}
	279	if (unlikely((address >> 32) != 0)) {
	280	bogus_32bit_fault_address(regs, address);
	281	goto intr_or_no_mm;
	282	}
eeabac73 DM	283	}
eeabac73 DM	284
1da177e4	285	if (regs->tstate & TSTATE_PRIV) {
9b026058	286	unsigned long tpc = regs->tpc;
1da177e4 LT	287
1da177e4 LT	288	/* Sanity check the PC. */
be71716e	289	if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) \|\|
1da177e4 LT	290	(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
	291	/* Valid, no problems... */
	292	} else {
bf941d6c	293	bad_kernel_pc(regs, address);
1da177e4 LT	294	return;
	295	}
	296	}
	297
	298	/*
	299	* If we're in an interrupt or have no user
	300	* context, we must not take the fault..
	301	*/
	302	if (in_atomic() \|\| !mm)
	303	goto intr_or_no_mm;
	304
1da177e4 LT	305	if (!down_read_trylock(&mm->mmap_sem)) {
	306	if ((regs->tstate & TSTATE_PRIV) &&
	307	!search_exception_tables(regs->tpc)) {
	308	insn = get_fault_insn(regs, insn);
	309	goto handle_kernel_fault;
	310	}
	311	down_read(&mm->mmap_sem);
	312	}
	313
	314	vma = find_vma(mm, address);
	315	if (!vma)
	316	goto bad_area;
	317
	318	/* Pure DTLB misses do not tell us whether the fault causing
	319	* load/store/atomic was a write or not, it only says that there
	320	* was no match. So in such a case we (carefully) read the
	321	* instruction to try and figure this out. It's an optimization
	322	* so it's ok if we can't do this.
	323	*
	324	* Special hack, window spill/fill knows the exact fault type.
	325	*/
	326	if (((fault_code &
	327	(FAULT_CODE_DTLB \| FAULT_CODE_WRITE \| FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
	328	(vma->vm_flags & VM_WRITE) != 0) {
	329	insn = get_fault_insn(regs, 0);
	330	if (!insn)
	331	goto continue_fault;
73c50a27 DM	332	/* All loads, stores and atomics have bits 30 and 31 both set
	333	* in the instruction. Bit 21 is set in all stores, but we
	334	* have to avoid prefetches which also have bit 21 set.
	335	*/
1da177e4	336	if ((insn & 0xc0200000) == 0xc0200000 &&
73c50a27	337	(insn & 0x01780000) != 0x01680000) {
1da177e4 LT	338	/* Don't bother updating thread struct value,
	339	* because update_mmu_cache only cares which tlb
	340	* the access came from.
	341	*/
	342	fault_code \|= FAULT_CODE_WRITE;
	343	}
	344	}
	345	continue_fault:
	346
	347	if (vma->vm_start <= address)
	348	goto good_area;
	349	if (!(vma->vm_flags & VM_GROWSDOWN))
	350	goto bad_area;
	351	if (!(fault_code & FAULT_CODE_WRITE)) {
	352	/* Non-faulting loads shouldn't expand stack. */
	353	insn = get_fault_insn(regs, insn);
	354	if ((insn & 0xc0800000) == 0xc0800000) {
	355	unsigned char asi;
	356
	357	if (insn & 0x2000)
	358	asi = (regs->tstate >> 24);
	359	else
	360	asi = (insn >> 5);
	361	if ((asi & 0xf2) == 0x82)
	362	goto bad_area;
	363	}
	364	}
	365	if (expand_stack(vma, address))
	366	goto bad_area;
	367	/*
	368	* Ok, we have a good vm_area for this memory access, so
	369	* we can handle it..
	370	*/
	371	good_area:
	372	si_code = SEGV_ACCERR;
	373
	374	/* If we took a ITLB miss on a non-executable page, catch
	375	* that here.
	376	*/
	377	if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
	378	BUG_ON(address != regs->tpc);
	379	BUG_ON(regs->tstate & TSTATE_PRIV);
	380	goto bad_area;
	381	}
	382
	383	if (fault_code & FAULT_CODE_WRITE) {
	384	if (!(vma->vm_flags & VM_WRITE))
	385	goto bad_area;
	386
	387	/* Spitfire has an icache which does not snoop
	388	* processor stores. Later processors do...
	389	*/
	390	if (tlb_type == spitfire &&
	391	(vma->vm_flags & VM_EXEC) != 0 &&
	392	vma->vm_file != NULL)
	393	set_thread_fault_code(fault_code \|
	394	FAULT_CODE_BLKCOMMIT);
	395	} else {
	396	/* Allow reads even for write-only mappings */
	397	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	398	goto bad_area;
	399	}
	400
d06063cc	401	fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE) ? FAULT_FLAG_WRITE : 0);
83c54070 NP	402	if (unlikely(fault & VM_FAULT_ERROR)) {
	403	if (fault & VM_FAULT_OOM)
	404	goto out_of_memory;
	405	else if (fault & VM_FAULT_SIGBUS)
	406	goto do_sigbus;
1da177e4 LT	407	BUG();
1da177e4 LT	408	}
83c54070 NP	409	if (fault & VM_FAULT_MAJOR)
	410	current->maj_flt++;
	411	else
	412	current->min_flt++;
1da177e4 LT	413
1da177e4 LT	414	up_read(&mm->mmap_sem);
7a1ac526 DM	415
7a1ac526 DM	416	mm_rss = get_mm_rss(mm);
dcc1e8dd DM	417	#ifdef CONFIG_HUGETLB_PAGE
	418	mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
	419	#endif
7bebd83d	420	if (unlikely(mm_rss >
dcc1e8dd DM	421	mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
	422	tsb_grow(mm, MM_TSB_BASE, mm_rss);
	423	#ifdef CONFIG_HUGETLB_PAGE
	424	mm_rss = mm->context.huge_pte_count;
7bebd83d	425	if (unlikely(mm_rss >
dcc1e8dd DM	426	mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit))
	427	tsb_grow(mm, MM_TSB_HUGE, mm_rss);
	428	#endif
efdc1e20	429	return;
1da177e4 LT	430
	431	/*
	432	* Something tried to access memory that isn't in our memory map..
	433	* Fix it, but check if it's kernel or user first..
	434	*/
	435	bad_area:
	436	insn = get_fault_insn(regs, insn);
	437	up_read(&mm->mmap_sem);
	438
	439	handle_kernel_fault:
	440	do_kernel_fault(regs, si_code, fault_code, insn, address);
efdc1e20	441	return;
1da177e4 LT	442
	443	/*
	444	* We ran out of memory, or some other thing happened to us that made
	445	* us unable to handle the page fault gracefully.
	446	*/
	447	out_of_memory:
	448	insn = get_fault_insn(regs, insn);
	449	up_read(&mm->mmap_sem);
	450	printk("VM: killing process %s\n", current->comm);
	451	if (!(regs->tstate & TSTATE_PRIV))
dcca2bde	452	do_group_exit(SIGKILL);
1da177e4 LT	453	goto handle_kernel_fault;
	454
	455	intr_or_no_mm:
	456	insn = get_fault_insn(regs, 0);
	457	goto handle_kernel_fault;
	458
	459	do_sigbus:
	460	insn = get_fault_insn(regs, insn);
	461	up_read(&mm->mmap_sem);
	462
	463	/*
	464	* Send a sigbus, regardless of whether we were in kernel
	465	* or user mode.
	466	*/
	467	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
	468
	469	/* Kernel mode? Handle exceptions or die */
	470	if (regs->tstate & TSTATE_PRIV)
	471	goto handle_kernel_fault;
1da177e4	472	}