[net-next-2.6.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/perf_event.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>

static inline __kprobes int notify_page_fault(struct pt_regs *regs)
{
	int ret = 0;

	/* kprobe_running() needs smp_processor_id() */
	if (kprobes_built_in() && !user_mode(regs)) {
		preempt_disable();
		if (kprobe_running() && kprobe_fault_handler(regs, 0))
			ret = 1;
		preempt_enable();
	}
	return ret;
}

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 __kprobes 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 __kprobes 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 __kprobes 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 __kprobes 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;

	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);

	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++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
			      regs, address);
	} else {
		current->min_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
			      regs, address);
	}
	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);
	if (!(regs->tstate & TSTATE_PRIV)) {
		pagefault_out_of_memory();
		return;
	}
	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	18	#include <linux/init.h>
a084b667	19	#include <linux/perf_event.h>
1da177e4	20	#include <linux/interrupt.h>
05e14cb3	21	#include <linux/kprobes.h>
1eeb66a1	22	#include <linux/kdebug.h>
eeabac73	23	#include <linux/percpu.h>
1da177e4 LT	24
	25	#include <asm/page.h>
	26	#include <asm/pgtable.h>
	27	#include <asm/openprom.h>
	28	#include <asm/oplib.h>
	29	#include <asm/uaccess.h>
	30	#include <asm/asi.h>
	31	#include <asm/lsu.h>
	32	#include <asm/sections.h>
7a1ac526	33	#include <asm/mmu_context.h>
1da177e4	34
4ed5d5e4	35	static inline __kprobes int notify_page_fault(struct pt_regs *regs)
d98f8f05	36	{
127cda1e DM	37	int ret = 0;
	38
	39	/* kprobe_running() needs smp_processor_id() */
135d0821	40	if (kprobes_built_in() && !user_mode(regs)) {
127cda1e DM	41	preempt_disable();
	42	if (kprobe_running() && kprobe_fault_handler(regs, 0))
	43	ret = 1;
	44	preempt_enable();
	45	}
	46	return ret;
d98f8f05	47	}
d98f8f05	48
05e14cb3 PP	49	static void __kprobes unhandled_fault(unsigned long address,
	50	struct task_struct *tsk,
	51	struct pt_regs *regs)
1da177e4 LT	52	{
	53	if ((unsigned long) address < PAGE_SIZE) {
	54	printk(KERN_ALERT "Unable to handle kernel NULL "
	55	"pointer dereference\n");
	56	} else {
	57	printk(KERN_ALERT "Unable to handle kernel paging request "
	58	"at virtual address %016lx\n", (unsigned long)address);
	59	}
	60	printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
	61	(tsk->mm ?
	62	CTX_HWBITS(tsk->mm->context) :
	63	CTX_HWBITS(tsk->active_mm->context)));
	64	printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
	65	(tsk->mm ? (unsigned long) tsk->mm->pgd :
	66	(unsigned long) tsk->active_mm->pgd));
1da177e4 LT	67	die_if_kernel("Oops", regs);
	68	}
	69
4ed5d5e4	70	static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
1da177e4	71	{
1da177e4 LT	72	printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
1da177e4 LT	73	regs->tpc);
eb398d10	74	printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
4fe3ebec	75	printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
bf941d6c	76	printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
c1f193a7	77	dump_stack();
1da177e4 LT	78	unhandled_fault(regs->tpc, current, regs);
	79	}
	80
	81	/*
	82	* We now make sure that mmap_sem is held in all paths that call
	83	* this. Additionally, to prevent kswapd from ripping ptes from
	84	* under us, raise interrupts around the time that we look at the
	85	* pte, kswapd will have to wait to get his smp ipi response from
da160546	86	* us. vmtruncate likewise. This saves us having to get pte lock.
1da177e4 LT	87	*/
	88	static unsigned int get_user_insn(unsigned long tpc)
	89	{
	90	pgd_t *pgdp = pgd_offset(current->mm, tpc);
	91	pud_t *pudp;
	92	pmd_t *pmdp;
	93	pte_t *ptep, pte;
	94	unsigned long pa;
	95	u32 insn = 0;
	96	unsigned long pstate;
	97
	98	if (pgd_none(*pgdp))
	99	goto outret;
	100	pudp = pud_offset(pgdp, tpc);
	101	if (pud_none(*pudp))
	102	goto outret;
	103	pmdp = pmd_offset(pudp, tpc);
	104	if (pmd_none(*pmdp))
	105	goto outret;
	106
	107	/* This disables preemption for us as well. */
	108	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	109	__asm__ __volatile__("wrpr %0, %1, %%pstate"
	110	: : "r" (pstate), "i" (PSTATE_IE));
	111	ptep = pte_offset_map(pmdp, tpc);
	112	pte = *ptep;
	113	if (!pte_present(pte))
	114	goto out;
	115
c4bce90e	116	pa = (pte_pfn(pte) << PAGE_SHIFT);
1da177e4 LT	117	pa += (tpc & ~PAGE_MASK);
	118
	119	/* Use phys bypass so we don't pollute dtlb/dcache. */
	120	__asm__ __volatile__("lduwa [%1] %2, %0"
	121	: "=r" (insn)
	122	: "r" (pa), "i" (ASI_PHYS_USE_EC));
	123
	124	out:
	125	pte_unmap(ptep);
	126	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
	127	outret:
	128	return insn;
	129	}
	130
	131	extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
	132
	133	static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
	134	unsigned int insn, int fault_code)
	135	{
	136	siginfo_t info;
	137
	138	info.si_code = code;
	139	info.si_signo = sig;
	140	info.si_errno = 0;
	141	if (fault_code & FAULT_CODE_ITLB)
	142	info.si_addr = (void __user *) regs->tpc;
	143	else
	144	info.si_addr = (void __user *)
	145	compute_effective_address(regs, insn, 0);
	146	info.si_trapno = 0;
	147	force_sig_info(sig, &info, current);
	148	}
	149
	150	extern int handle_ldf_stq(u32, struct pt_regs *);
	151	extern int handle_ld_nf(u32, struct pt_regs *);
	152
	153	static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
	154	{
	155	if (!insn) {
	156	if (!regs->tpc \|\| (regs->tpc & 0x3))
	157	return 0;
	158	if (regs->tstate & TSTATE_PRIV) {
	159	insn = (unsigned int ) regs->tpc;
	160	} else {
	161	insn = get_user_insn(regs->tpc);
	162	}
	163	}
	164	return insn;
	165	}
	166
4ed5d5e4 DM	167	static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
	168	int fault_code, unsigned int insn,
	169	unsigned long address)
1da177e4	170	{
1da177e4 LT	171	unsigned char asi = ASI_P;
	172
	173	if ((!insn) && (regs->tstate & TSTATE_PRIV))
	174	goto cannot_handle;
	175
	176	/* If user insn could be read (thus insn is zero), that
	177	* is fine. We will just gun down the process with a signal
	178	* in that case.
	179	*/
	180
	181	if (!(fault_code & (FAULT_CODE_WRITE\|FAULT_CODE_ITLB)) &&
	182	(insn & 0xc0800000) == 0xc0800000) {
	183	if (insn & 0x2000)
	184	asi = (regs->tstate >> 24);
	185	else
	186	asi = (insn >> 5);
	187	if ((asi & 0xf2) == 0x82) {
	188	if (insn & 0x1000000) {
	189	handle_ldf_stq(insn, regs);
	190	} else {
	191	/* This was a non-faulting load. Just clear the
	192	* destination register(s) and continue with the next
	193	* instruction. -jj
	194	*/
	195	handle_ld_nf(insn, regs);
	196	}
	197	return;
	198	}
	199	}
	200
1da177e4 LT	201	/* Is this in ex_table? */
1da177e4 LT	202	if (regs->tstate & TSTATE_PRIV) {
8cf14af0	203	const struct exception_table_entry *entry;
1da177e4	204
622eaec6 DM	205	entry = search_exception_tables(regs->tpc);
622eaec6 DM	206	if (entry) {
8cf14af0	207	regs->tpc = entry->fixup;
1da177e4	208	regs->tnpc = regs->tpc + 4;
1da177e4 LT	209	return;
	210	}
	211	} else {
	212	/* The si_code was set to make clear whether
	213	* this was a SEGV_MAPERR or SEGV_ACCERR fault.
	214	*/
	215	do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
	216	return;
	217	}
	218
	219	cannot_handle:
	220	unhandled_fault (address, current, regs);
	221	}
	222
4ed5d5e4	223	static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
9b026058 DM	224	{
	225	static int times;
	226
	227	if (times++ < 10)
	228	printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
	229	"64-bit TPC [%lx]\n",
	230	current->comm, current->pid,
	231	regs->tpc);
	232	show_regs(regs);
	233	}
	234
4ed5d5e4 DM	235	static void noinline __kprobes bogus_32bit_fault_address(struct pt_regs *regs,
4ed5d5e4 DM	236	unsigned long addr)
9b026058 DM	237	{
	238	static int times;
	239
	240	if (times++ < 10)
	241	printk(KERN_ERR "FAULT[%s:%d]: 32-bit process "
	242	"reports 64-bit fault address [%lx]\n",
	243	current->comm, current->pid, addr);
	244	show_regs(regs);
	245	}
	246
05e14cb3	247	asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
1da177e4 LT	248	{
	249	struct mm_struct *mm = current->mm;
	250	struct vm_area_struct *vma;
	251	unsigned int insn = 0;
83c54070	252	int si_code, fault_code, fault;
7a1ac526	253	unsigned long address, mm_rss;
1da177e4 LT	254
	255	fault_code = get_thread_fault_code();
	256
127cda1e	257	if (notify_page_fault(regs))
1da177e4 LT	258	return;
	259
	260	si_code = SEGV_MAPERR;
	261	address = current_thread_info()->fault_address;
	262
	263	if ((fault_code & FAULT_CODE_ITLB) &&
	264	(fault_code & FAULT_CODE_DTLB))
	265	BUG();
	266
eeabac73	267	if (test_thread_flag(TIF_32BIT)) {
9b026058 DM	268	if (!(regs->tstate & TSTATE_PRIV)) {
	269	if (unlikely((regs->tpc >> 32) != 0)) {
	270	bogus_32bit_fault_tpc(regs);
	271	goto intr_or_no_mm;
	272	}
	273	}
	274	if (unlikely((address >> 32) != 0)) {
	275	bogus_32bit_fault_address(regs, address);
	276	goto intr_or_no_mm;
	277	}
eeabac73 DM	278	}
eeabac73 DM	279
1da177e4	280	if (regs->tstate & TSTATE_PRIV) {
9b026058	281	unsigned long tpc = regs->tpc;
1da177e4 LT	282
1da177e4 LT	283	/* Sanity check the PC. */
be71716e	284	if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) \|\|
1da177e4 LT	285	(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
	286	/* Valid, no problems... */
	287	} else {
bf941d6c	288	bad_kernel_pc(regs, address);
1da177e4 LT	289	return;
	290	}
	291	}
	292
	293	/*
	294	* If we're in an interrupt or have no user
	295	* context, we must not take the fault..
	296	*/
	297	if (in_atomic() \|\| !mm)
	298	goto intr_or_no_mm;
	299
a084b667 DM	300	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
a084b667 DM	301
1da177e4 LT	302	if (!down_read_trylock(&mm->mmap_sem)) {
	303	if ((regs->tstate & TSTATE_PRIV) &&
	304	!search_exception_tables(regs->tpc)) {
	305	insn = get_fault_insn(regs, insn);
	306	goto handle_kernel_fault;
	307	}
	308	down_read(&mm->mmap_sem);
	309	}
	310
	311	vma = find_vma(mm, address);
	312	if (!vma)
	313	goto bad_area;
	314
	315	/* Pure DTLB misses do not tell us whether the fault causing
	316	* load/store/atomic was a write or not, it only says that there
	317	* was no match. So in such a case we (carefully) read the
	318	* instruction to try and figure this out. It's an optimization
	319	* so it's ok if we can't do this.
	320	*
	321	* Special hack, window spill/fill knows the exact fault type.
	322	*/
	323	if (((fault_code &
	324	(FAULT_CODE_DTLB \| FAULT_CODE_WRITE \| FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
	325	(vma->vm_flags & VM_WRITE) != 0) {
	326	insn = get_fault_insn(regs, 0);
	327	if (!insn)
	328	goto continue_fault;
73c50a27 DM	329	/* All loads, stores and atomics have bits 30 and 31 both set
	330	* in the instruction. Bit 21 is set in all stores, but we
	331	* have to avoid prefetches which also have bit 21 set.
	332	*/
1da177e4	333	if ((insn & 0xc0200000) == 0xc0200000 &&
73c50a27	334	(insn & 0x01780000) != 0x01680000) {
1da177e4 LT	335	/* Don't bother updating thread struct value,
	336	* because update_mmu_cache only cares which tlb
	337	* the access came from.
	338	*/
	339	fault_code \|= FAULT_CODE_WRITE;
	340	}
	341	}
	342	continue_fault:
	343
	344	if (vma->vm_start <= address)
	345	goto good_area;
	346	if (!(vma->vm_flags & VM_GROWSDOWN))
	347	goto bad_area;
	348	if (!(fault_code & FAULT_CODE_WRITE)) {
	349	/* Non-faulting loads shouldn't expand stack. */
	350	insn = get_fault_insn(regs, insn);
	351	if ((insn & 0xc0800000) == 0xc0800000) {
	352	unsigned char asi;
	353
	354	if (insn & 0x2000)
	355	asi = (regs->tstate >> 24);
	356	else
	357	asi = (insn >> 5);
	358	if ((asi & 0xf2) == 0x82)
	359	goto bad_area;
	360	}
	361	}
	362	if (expand_stack(vma, address))
	363	goto bad_area;
	364	/*
	365	* Ok, we have a good vm_area for this memory access, so
	366	* we can handle it..
	367	*/
	368	good_area:
	369	si_code = SEGV_ACCERR;
	370
	371	/* If we took a ITLB miss on a non-executable page, catch
	372	* that here.
	373	*/
	374	if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
	375	BUG_ON(address != regs->tpc);
	376	BUG_ON(regs->tstate & TSTATE_PRIV);
	377	goto bad_area;
	378	}
	379
	380	if (fault_code & FAULT_CODE_WRITE) {
	381	if (!(vma->vm_flags & VM_WRITE))
	382	goto bad_area;
	383
	384	/* Spitfire has an icache which does not snoop
	385	* processor stores. Later processors do...
	386	*/
	387	if (tlb_type == spitfire &&
	388	(vma->vm_flags & VM_EXEC) != 0 &&
	389	vma->vm_file != NULL)
	390	set_thread_fault_code(fault_code \|
	391	FAULT_CODE_BLKCOMMIT);
	392	} else {
	393	/* Allow reads even for write-only mappings */
	394	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	395	goto bad_area;
	396	}
	397
d06063cc	398	fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE) ? FAULT_FLAG_WRITE : 0);
83c54070 NP	399	if (unlikely(fault & VM_FAULT_ERROR)) {
	400	if (fault & VM_FAULT_OOM)
	401	goto out_of_memory;
	402	else if (fault & VM_FAULT_SIGBUS)
	403	goto do_sigbus;
1da177e4 LT	404	BUG();
1da177e4 LT	405	}
a084b667	406	if (fault & VM_FAULT_MAJOR) {
83c54070	407	current->maj_flt++;
a084b667 DM	408	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
	409	regs, address);
	410	} else {
83c54070	411	current->min_flt++;
a084b667 DM	412	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
	413	regs, address);
	414	}
1da177e4	415	up_read(&mm->mmap_sem);
7a1ac526 DM	416
7a1ac526 DM	417	mm_rss = get_mm_rss(mm);
dcc1e8dd DM	418	#ifdef CONFIG_HUGETLB_PAGE
	419	mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
	420	#endif
7bebd83d	421	if (unlikely(mm_rss >
dcc1e8dd DM	422	mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
	423	tsb_grow(mm, MM_TSB_BASE, mm_rss);
	424	#ifdef CONFIG_HUGETLB_PAGE
	425	mm_rss = mm->context.huge_pte_count;
7bebd83d	426	if (unlikely(mm_rss >
dcc1e8dd DM	427	mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit))
	428	tsb_grow(mm, MM_TSB_HUGE, mm_rss);
	429	#endif
efdc1e20	430	return;
1da177e4 LT	431
	432	/*
	433	* Something tried to access memory that isn't in our memory map..
	434	* Fix it, but check if it's kernel or user first..
	435	*/
	436	bad_area:
	437	insn = get_fault_insn(regs, insn);
	438	up_read(&mm->mmap_sem);
	439
	440	handle_kernel_fault:
	441	do_kernel_fault(regs, si_code, fault_code, insn, address);
efdc1e20	442	return;
1da177e4 LT	443
	444	/*
	445	* We ran out of memory, or some other thing happened to us that made
	446	* us unable to handle the page fault gracefully.
	447	*/
	448	out_of_memory:
	449	insn = get_fault_insn(regs, insn);
	450	up_read(&mm->mmap_sem);
a923c28f DM	451	if (!(regs->tstate & TSTATE_PRIV)) {
	452	pagefault_out_of_memory();
	453	return;
	454	}
1da177e4 LT	455	goto handle_kernel_fault;
	456
	457	intr_or_no_mm:
	458	insn = get_fault_insn(regs, 0);
	459	goto handle_kernel_fault;
	460
	461	do_sigbus:
	462	insn = get_fault_insn(regs, insn);
	463	up_read(&mm->mmap_sem);
	464
	465	/*
	466	* Send a sigbus, regardless of whether we were in kernel
	467	* or user mode.
	468	*/
	469	do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
	470
	471	/* Kernel mode? Handle exceptions or die */
	472	if (regs->tstate & TSTATE_PRIV)
	473	goto handle_kernel_fault;
1da177e4	474	}