Initial import

1 files changed, 544 insertions, 0 deletions

diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
new file mode 100644
index 000000000..479823249
--- /dev/null
+++ b/arch/sparc/mm/fault_64.c
@@ -0,0 +1,544 @@
+/*
+ * 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 <linux/context_tracking.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>
+#include <asm/setup.h>
+
+int show_unhandled_signals = 1;
+
+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;
+
+	if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp)))
+		goto out;
+	pudp = pud_offset(pgdp, tpc);
+	if (pud_none(*pudp) || unlikely(pud_bad(*pudp)))
+		goto out;
+
+	/* This disables preemption for us as well. */
+	local_irq_disable();
+
+	pmdp = pmd_offset(pudp, tpc);
+	if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp)))
+		goto out_irq_enable;
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (pmd_trans_huge(*pmdp)) {
+		if (pmd_trans_splitting(*pmdp))
+			goto out_irq_enable;
+
+		pa  = pmd_pfn(*pmdp) << PAGE_SHIFT;
+		pa += tpc & ~HPAGE_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));
+	} else
+#endif
+	{
+		ptep = pte_offset_map(pmdp, tpc);
+		pte = *ptep;
+		if (pte_present(pte)) {
+			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));
+		}
+		pte_unmap(ptep);
+	}
+out_irq_enable:
+	local_irq_enable();
+out:
+	return insn;
+}
+
+static inline void
+show_signal_msg(struct pt_regs *regs, int sig, int code,
+		unsigned long address, struct task_struct *tsk)
+{
+	if (!unhandled_signal(tsk, sig))
+		return;
+
+	if (!printk_ratelimit())
+		return;
+
+	printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
+	       task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+	       tsk->comm, task_pid_nr(tsk), address,
+	       (void *)regs->tpc, (void *)regs->u_regs[UREG_I7],
+	       (void *)regs->u_regs[UREG_FP], code);
+
+	print_vma_addr(KERN_CONT " in ", regs->tpc);
+
+	printk(KERN_CONT "\n");
+}
+
+static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
+			     unsigned long fault_addr, unsigned int insn,
+			     int fault_code)
+{
+	unsigned long addr;
+	siginfo_t info;
+
+	info.si_code = code;
+	info.si_signo = sig;
+	info.si_errno = 0;
+	if (fault_code & FAULT_CODE_ITLB) {
+		addr = regs->tpc;
+	} else {
+		/* If we were able to probe the faulting instruction, use it
+		 * to compute a precise fault address.  Otherwise use the fault
+		 * time provided address which may only have page granularity.
+		 */
+		if (insn)
+			addr = compute_effective_address(regs, insn, 0);
+		else
+			addr = fault_addr;
+	}
+	info.si_addr = (void __user *) addr;
+	info.si_trapno = 0;
+
+	if (unlikely(show_unhandled_signals))
+		show_signal_msg(regs, sig, code, addr, current);
+
+	force_sig_info(sig, &info, current);
+}
+
+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, address, 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);
+}
+
+asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
+{
+	enum ctx_state prev_state = exception_enter();
+	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;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+	fault_code = get_thread_fault_code();
+
+	if (notify_page_fault(regs))
+		goto exit_exception;
+
+	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))
+			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);
+			goto exit_exception;
+		}
+	} else
+		flags |= FAULT_FLAG_USER;
+
+	/*
+	 * 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, 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;
+		}
+
+retry:
+		down_read(&mm->mmap_sem);
+	}
+
+	if (fault_code & FAULT_CODE_BAD_RA)
+		goto do_sigbus;
+
+	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);
+
+		flags |= FAULT_FLAG_WRITE;
+	} 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, flags);
+
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+		goto exit_exception;
+
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGSEGV)
+			goto bad_area;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		BUG();
+	}
+
+	if (flags & FAULT_FLAG_ALLOW_RETRY) {
+		if (fault & VM_FAULT_MAJOR) {
+			current->maj_flt++;
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
+				      1, regs, address);
+		} else {
+			current->min_flt++;
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
+				      1, regs, address);
+		}
+		if (fault & VM_FAULT_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+			flags |= FAULT_FLAG_TRIED;
+
+			/* No need to up_read(&mm->mmap_sem) as we would
+			 * have already released it in __lock_page_or_retry
+			 * in mm/filemap.c.
+			 */
+
+			goto retry;
+		}
+	}
+	up_read(&mm->mmap_sem);
+
+	mm_rss = get_mm_rss(mm);
+#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
+	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);
+#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
+	mm_rss = mm->context.huge_pte_count;
+	if (unlikely(mm_rss >
+		     mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) {
+		if (mm->context.tsb_block[MM_TSB_HUGE].tsb)
+			tsb_grow(mm, MM_TSB_HUGE, mm_rss);
+		else
+			hugetlb_setup(regs);
+
+	}
+#endif
+exit_exception:
+	exception_exit(prev_state);
+	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);
+	goto exit_exception;
+
+/*
+ * 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();
+		goto exit_exception;
+	}
+	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, address, insn, fault_code);
+
+	/* Kernel mode? Handle exceptions or die */
+	if (regs->tstate & TSTATE_PRIV)
+		goto handle_kernel_fault;
+}