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-rw-r--r--arch/m68k/mm/fault.c219
1 files changed, 219 insertions, 0 deletions
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
new file mode 100644
index 00000000000..ac48b6d2aff
--- /dev/null
+++ b/arch/m68k/mm/fault.c
@@ -0,0 +1,219 @@
+/*
+ * linux/arch/m68k/mm/fault.c
+ *
+ * Copyright (C) 1995 Hamish Macdonald
+ */
+
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+
+#include <asm/setup.h>
+#include <asm/traps.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+
+extern void die_if_kernel(char *, struct pt_regs *, long);
+extern const int frame_extra_sizes[]; /* in m68k/kernel/signal.c */
+
+int send_fault_sig(struct pt_regs *regs)
+{
+ siginfo_t siginfo = { 0, 0, 0, };
+
+ siginfo.si_signo = current->thread.signo;
+ siginfo.si_code = current->thread.code;
+ siginfo.si_addr = (void *)current->thread.faddr;
+#ifdef DEBUG
+ printk("send_fault_sig: %p,%d,%d\n", siginfo.si_addr, siginfo.si_signo, siginfo.si_code);
+#endif
+
+ if (user_mode(regs)) {
+ force_sig_info(siginfo.si_signo,
+ &siginfo, current);
+ } else {
+ const struct exception_table_entry *fixup;
+
+ /* Are we prepared to handle this kernel fault? */
+ if ((fixup = search_exception_tables(regs->pc))) {
+ struct pt_regs *tregs;
+ /* Create a new four word stack frame, discarding the old
+ one. */
+ regs->stkadj = frame_extra_sizes[regs->format];
+ tregs = (struct pt_regs *)((ulong)regs + regs->stkadj);
+ tregs->vector = regs->vector;
+ tregs->format = 0;
+ tregs->pc = fixup->fixup;
+ tregs->sr = regs->sr;
+ return -1;
+ }
+
+ //if (siginfo.si_signo == SIGBUS)
+ // force_sig_info(siginfo.si_signo,
+ // &siginfo, current);
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ if ((unsigned long)siginfo.si_addr < PAGE_SIZE)
+ printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
+ else
+ printk(KERN_ALERT "Unable to handle kernel access");
+ printk(" at virtual address %p\n", siginfo.si_addr);
+ die_if_kernel("Oops", regs, 0 /*error_code*/);
+ do_exit(SIGKILL);
+ }
+
+ return 1;
+}
+
+/*
+ * This routine handles page faults. It determines the problem, and
+ * then passes it off to one of the appropriate routines.
+ *
+ * error_code:
+ * bit 0 == 0 means no page found, 1 means protection fault
+ * bit 1 == 0 means read, 1 means write
+ *
+ * If this routine detects a bad access, it returns 1, otherwise it
+ * returns 0.
+ */
+int do_page_fault(struct pt_regs *regs, unsigned long address,
+ unsigned long error_code)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct * vma;
+ int write, fault;
+
+#ifdef DEBUG
+ printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",
+ regs->sr, regs->pc, address, error_code,
+ current->mm->pgd);
+#endif
+
+ /*
+ * If we're in an interrupt or have no user
+ * context, we must not take the fault..
+ */
+ if (in_interrupt() || !mm)
+ goto no_context;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, address);
+ if (!vma)
+ goto map_err;
+ if (vma->vm_flags & VM_IO)
+ goto acc_err;
+ if (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto map_err;
+ if (user_mode(regs)) {
+ /* Accessing the stack below usp is always a bug. The
+ "+ 256" is there due to some instructions doing
+ pre-decrement on the stack and that doesn't show up
+ until later. */
+ if (address + 256 < rdusp())
+ goto map_err;
+ }
+ if (expand_stack(vma, address))
+ goto map_err;
+
+/*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+#ifdef DEBUG
+ printk("do_page_fault: good_area\n");
+#endif
+ write = 0;
+ switch (error_code & 3) {
+ default: /* 3: write, present */
+ /* fall through */
+ case 2: /* write, not present */
+ if (!(vma->vm_flags & VM_WRITE))
+ goto acc_err;
+ write++;
+ break;
+ case 1: /* read, present */
+ goto acc_err;
+ case 0: /* read, not present */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto acc_err;
+ }
+
+ /*
+ * If for any reason at all we couldn't handle the fault,
+ * make sure we exit gracefully rather than endlessly redo
+ * the fault.
+ */
+
+ survive:
+ fault = handle_mm_fault(mm, vma, address, write);
+#ifdef DEBUG
+ printk("handle_mm_fault returns %d\n",fault);
+#endif
+ switch (fault) {
+ case 1:
+ current->min_flt++;
+ break;
+ case 2:
+ current->maj_flt++;
+ break;
+ case 0:
+ goto bus_err;
+ default:
+ goto out_of_memory;
+ }
+
+ up_read(&mm->mmap_sem);
+ return 0;
+
+/*
+ * 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:
+ up_read(&mm->mmap_sem);
+ if (current->pid == 1) {
+ yield();
+ down_read(&mm->mmap_sem);
+ goto survive;
+ }
+
+ printk("VM: killing process %s\n", current->comm);
+ if (user_mode(regs))
+ do_exit(SIGKILL);
+
+no_context:
+ current->thread.signo = SIGBUS;
+ current->thread.faddr = address;
+ return send_fault_sig(regs);
+
+bus_err:
+ current->thread.signo = SIGBUS;
+ current->thread.code = BUS_ADRERR;
+ current->thread.faddr = address;
+ goto send_sig;
+
+map_err:
+ current->thread.signo = SIGSEGV;
+ current->thread.code = SEGV_MAPERR;
+ current->thread.faddr = address;
+ goto send_sig;
+
+acc_err:
+ current->thread.signo = SIGSEGV;
+ current->thread.code = SEGV_ACCERR;
+ current->thread.faddr = address;
+
+send_sig:
+ up_read(&mm->mmap_sem);
+ return send_fault_sig(regs);
+}