Initial import

1 files changed, 351 insertions, 0 deletions

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
new file mode 100644
index 000000000..e5120e653
--- /dev/null
+++ b/arch/parisc/mm/fault.c
@@ -0,0 +1,351 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ *
+ * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
+ * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
+ * Copyright 1999 Hewlett Packard Co.
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+
+#include <asm/uaccess.h>
+#include <asm/traps.h>
+
+/* Various important other fields */
+#define bit22set(x)		(x & 0x00000200)
+#define bits23_25set(x)		(x & 0x000001c0)
+#define isGraphicsFlushRead(x)	((x & 0xfc003fdf) == 0x04001a80)
+				/* extended opcode is 0x6a */
+
+#define BITSSET		0x1c0	/* for identifying LDCW */
+
+
+DEFINE_PER_CPU(struct exception_data, exception_data);
+
+int show_unhandled_signals = 1;
+
+/*
+ * parisc_acctyp(unsigned int inst) --
+ *    Given a PA-RISC memory access instruction, determine if the
+ *    the instruction would perform a memory read or memory write
+ *    operation.
+ *
+ *    This function assumes that the given instruction is a memory access
+ *    instruction (i.e. you should really only call it if you know that
+ *    the instruction has generated some sort of a memory access fault).
+ *
+ * Returns:
+ *   VM_READ  if read operation
+ *   VM_WRITE if write operation
+ *   VM_EXEC  if execute operation
+ */
+static unsigned long
+parisc_acctyp(unsigned long code, unsigned int inst)
+{
+	if (code == 6 || code == 16)
+	    return VM_EXEC;
+
+	switch (inst & 0xf0000000) {
+	case 0x40000000: /* load */
+	case 0x50000000: /* new load */
+		return VM_READ;
+
+	case 0x60000000: /* store */
+	case 0x70000000: /* new store */
+		return VM_WRITE;
+
+	case 0x20000000: /* coproc */
+	case 0x30000000: /* coproc2 */
+		if (bit22set(inst))
+			return VM_WRITE;
+
+	case 0x0: /* indexed/memory management */
+		if (bit22set(inst)) {
+			/*
+			 * Check for the 'Graphics Flush Read' instruction.
+			 * It resembles an FDC instruction, except for bits
+			 * 20 and 21. Any combination other than zero will
+			 * utilize the block mover functionality on some
+			 * older PA-RISC platforms.  The case where a block
+			 * move is performed from VM to graphics IO space
+			 * should be treated as a READ.
+			 *
+			 * The significance of bits 20,21 in the FDC
+			 * instruction is:
+			 *
+			 *   00  Flush data cache (normal instruction behavior)
+			 *   01  Graphics flush write  (IO space -> VM)
+			 *   10  Graphics flush read   (VM -> IO space)
+			 *   11  Graphics flush read/write (VM <-> IO space)
+			 */
+			if (isGraphicsFlushRead(inst))
+				return VM_READ;
+			return VM_WRITE;
+		} else {
+			/*
+			 * Check for LDCWX and LDCWS (semaphore instructions).
+			 * If bits 23 through 25 are all 1's it is one of
+			 * the above two instructions and is a write.
+			 *
+			 * Note: With the limited bits we are looking at,
+			 * this will also catch PROBEW and PROBEWI. However,
+			 * these should never get in here because they don't
+			 * generate exceptions of the type:
+			 *   Data TLB miss fault/data page fault
+			 *   Data memory protection trap
+			 */
+			if (bits23_25set(inst) == BITSSET)
+				return VM_WRITE;
+		}
+		return VM_READ; /* Default */
+	}
+	return VM_READ; /* Default */
+}
+
+#undef bit22set
+#undef bits23_25set
+#undef isGraphicsFlushRead
+#undef BITSSET
+
+
+#if 0
+/* This is the treewalk to find a vma which is the highest that has
+ * a start < addr.  We're using find_vma_prev instead right now, but
+ * we might want to use this at some point in the future.  Probably
+ * not, but I want it committed to CVS so I don't lose it :-)
+ */
+			while (tree != vm_avl_empty) {
+				if (tree->vm_start > addr) {
+					tree = tree->vm_avl_left;
+				} else {
+					prev = tree;
+					if (prev->vm_next == NULL)
+						break;
+					if (prev->vm_next->vm_start > addr)
+						break;
+					tree = tree->vm_avl_right;
+				}
+			}
+#endif
+
+int fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *fix;
+
+	/* If we only stored 32bit addresses in the exception table we can drop
+	 * out if we faulted on a 64bit address. */
+	if ((sizeof(regs->iaoq[0]) > sizeof(fix->insn))
+		&& (regs->iaoq[0] >> 32))
+			return 0;
+
+	fix = search_exception_tables(regs->iaoq[0]);
+	if (fix) {
+		struct exception_data *d;
+		d = this_cpu_ptr(&exception_data);
+		d->fault_ip = regs->iaoq[0];
+		d->fault_space = regs->isr;
+		d->fault_addr = regs->ior;
+
+		regs->iaoq[0] = ((fix->fixup) & ~3);
+		/*
+		 * NOTE: In some cases the faulting instruction
+		 * may be in the delay slot of a branch. We
+		 * don't want to take the branch, so we don't
+		 * increment iaoq[1], instead we set it to be
+		 * iaoq[0]+4, and clear the B bit in the PSW
+		 */
+		regs->iaoq[1] = regs->iaoq[0] + 4;
+		regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
+
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * Print out info about fatal segfaults, if the show_unhandled_signals
+ * sysctl is set:
+ */
+static inline void
+show_signal_msg(struct pt_regs *regs, unsigned long code,
+		unsigned long address, struct task_struct *tsk,
+		struct vm_area_struct *vma)
+{
+	if (!unhandled_signal(tsk, SIGSEGV))
+		return;
+
+	if (!printk_ratelimit())
+		return;
+
+	pr_warn("\n");
+	pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
+	    tsk->comm, code, address);
+	print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
+	if (vma)
+		pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
+				vma->vm_start, vma->vm_end);
+
+	show_regs(regs);
+}
+
+void do_page_fault(struct pt_regs *regs, unsigned long code,
+			      unsigned long address)
+{
+	struct vm_area_struct *vma, *prev_vma;
+	struct task_struct *tsk;
+	struct mm_struct *mm;
+	unsigned long acc_type;
+	int fault;
+	unsigned int flags;
+
+	if (in_atomic())
+		goto no_context;
+
+	tsk = current;
+	mm = tsk->mm;
+	if (!mm)
+		goto no_context;
+
+	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+	if (user_mode(regs))
+		flags |= FAULT_FLAG_USER;
+
+	acc_type = parisc_acctyp(code, regs->iir);
+	if (acc_type & VM_WRITE)
+		flags |= FAULT_FLAG_WRITE;
+retry:
+	down_read(&mm->mmap_sem);
+	vma = find_vma_prev(mm, address, &prev_vma);
+	if (!vma || address < vma->vm_start)
+		goto check_expansion;
+/*
+ * Ok, we have a good vm_area for this memory access. We still need to
+ * check the access permissions.
+ */
+
+good_area:
+
+	if ((vma->vm_flags & acc_type) != acc_type)
+		goto bad_area;
+
+	/*
+	 * If for any reason at all we couldn't handle the fault, make
+	 * sure we exit gracefully rather than endlessly redo the
+	 * fault.
+	 */
+
+	fault = handle_mm_fault(mm, vma, address, flags);
+
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+		return;
+
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		/*
+		 * We hit a shared mapping outside of the file, or some
+		 * other thing happened to us that made us unable to
+		 * handle the page fault gracefully.
+		 */
+		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 bad_area;
+		BUG();
+	}
+	if (flags & FAULT_FLAG_ALLOW_RETRY) {
+		if (fault & VM_FAULT_MAJOR)
+			current->maj_flt++;
+		else
+			current->min_flt++;
+		if (fault & VM_FAULT_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+
+			/*
+			 * 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);
+	return;
+
+check_expansion:
+	vma = prev_vma;
+	if (vma && (expand_stack(vma, address) == 0))
+		goto good_area;
+
+/*
+ * Something tried to access memory that isn't in our memory map..
+ */
+bad_area:
+	up_read(&mm->mmap_sem);
+
+	if (user_mode(regs)) {
+		struct siginfo si;
+
+		show_signal_msg(regs, code, address, tsk, vma);
+
+		switch (code) {
+		case 15:	/* Data TLB miss fault/Data page fault */
+			/* send SIGSEGV when outside of vma */
+			if (!vma ||
+			    address < vma->vm_start || address > vma->vm_end) {
+				si.si_signo = SIGSEGV;
+				si.si_code = SEGV_MAPERR;
+				break;
+			}
+
+			/* send SIGSEGV for wrong permissions */
+			if ((vma->vm_flags & acc_type) != acc_type) {
+				si.si_signo = SIGSEGV;
+				si.si_code = SEGV_ACCERR;
+				break;
+			}
+
+			/* probably address is outside of mapped file */
+			/* fall through */
+		case 17:	/* NA data TLB miss / page fault */
+		case 18:	/* Unaligned access - PCXS only */
+			si.si_signo = SIGBUS;
+			si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
+			break;
+		case 16:	/* Non-access instruction TLB miss fault */
+		case 26:	/* PCXL: Data memory access rights trap */
+		default:
+			si.si_signo = SIGSEGV;
+			si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
+			break;
+		}
+		si.si_errno = 0;
+		si.si_addr = (void __user *) address;
+		force_sig_info(si.si_signo, &si, current);
+		return;
+	}
+
+no_context:
+
+	if (!user_mode(regs) && fixup_exception(regs)) {
+		return;
+	}
+
+	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
+
+  out_of_memory:
+	up_read(&mm->mmap_sem);
+	if (!user_mode(regs))
+		goto no_context;
+	pagefault_out_of_memory();
+}