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-rw-r--r--arch/mn10300/mm/fault.c393
1 files changed, 393 insertions, 0 deletions
diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c
new file mode 100644
index 00000000..0945409a
--- /dev/null
+++ b/arch/mn10300/mm/fault.c
@@ -0,0 +1,393 @@
+/* MN10300 MMU Fault handler
+ *
+ * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Modified by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/vt_kern.h> /* For unblank_screen() */
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/hardirq.h>
+#include <asm/cpu-regs.h>
+#include <asm/debugger.h>
+#include <asm/gdb-stub.h>
+
+/*
+ * Unlock any spinlocks which will prevent us from getting the
+ * message out
+ */
+void bust_spinlocks(int yes)
+{
+ if (yes) {
+ oops_in_progress = 1;
+ } else {
+ int loglevel_save = console_loglevel;
+#ifdef CONFIG_VT
+ unblank_screen();
+#endif
+ oops_in_progress = 0;
+ /*
+ * OK, the message is on the console. Now we call printk()
+ * without oops_in_progress set so that printk will give klogd
+ * a poke. Hold onto your hats...
+ */
+ console_loglevel = 15; /* NMI oopser may have shut the console
+ * up */
+ printk(" ");
+ console_loglevel = loglevel_save;
+ }
+}
+
+void do_BUG(const char *file, int line)
+{
+ bust_spinlocks(1);
+ printk(KERN_EMERG "------------[ cut here ]------------\n");
+ printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
+}
+
+#if 0
+static void print_pagetable_entries(pgd_t *pgdir, unsigned long address)
+{
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgdir + __pgd_offset(address);
+ printk(KERN_DEBUG "pgd entry %p: %016Lx\n",
+ pgd, (long long) pgd_val(*pgd));
+
+ if (!pgd_present(*pgd)) {
+ printk(KERN_DEBUG "... pgd not present!\n");
+ return;
+ }
+ pmd = pmd_offset(pgd, address);
+ printk(KERN_DEBUG "pmd entry %p: %016Lx\n",
+ pmd, (long long)pmd_val(*pmd));
+
+ if (!pmd_present(*pmd)) {
+ printk(KERN_DEBUG "... pmd not present!\n");
+ return;
+ }
+ pte = pte_offset(pmd, address);
+ printk(KERN_DEBUG "pte entry %p: %016Lx\n",
+ pte, (long long) pte_val(*pte));
+
+ if (!pte_present(*pte))
+ printk(KERN_DEBUG "... pte not present!\n");
+}
+#endif
+
+/*
+ * This routine handles page faults. It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ *
+ * fault_code:
+ * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate
+ * - MSW: 0 if data access, 1 if instruction access
+ * - bit 0: TLB miss flag
+ * - bit 1: initial write
+ * - bit 2: page invalid
+ * - bit 3: protection violation
+ * - bit 4: accessor (0=user 1=kernel)
+ * - bit 5: 0=read 1=write
+ * - bit 6-8: page protection spec
+ * - bit 9: illegal address
+ * - bit 16: 0=data 1=ins
+ *
+ */
+asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
+ unsigned long address)
+{
+ struct vm_area_struct *vma;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ unsigned long page;
+ siginfo_t info;
+ int write, fault;
+
+#ifdef CONFIG_GDBSTUB
+ /* handle GDB stub causing a fault */
+ if (gdbstub_busy) {
+ gdbstub_exception(regs, TBR & TBR_INT_CODE);
+ return;
+ }
+#endif
+
+#if 0
+ printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n",
+ regs,
+ fault_code & 0x10000 ? "ins" : "data",
+ fault_code & 0xffff, address);
+#endif
+
+ tsk = current;
+
+ /*
+ * We fault-in kernel-space virtual memory on-demand. The
+ * 'reference' page table is init_mm.pgd.
+ *
+ * NOTE! We MUST NOT take any locks for this case. We may
+ * be in an interrupt or a critical region, and should
+ * only copy the information from the master page table,
+ * nothing more.
+ *
+ * This verifies that the fault happens in kernel space
+ * and that the fault was a page not present (invalid) error
+ */
+ if (address >= VMALLOC_START && address < VMALLOC_END &&
+ (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR &&
+ (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL
+ )
+ goto vmalloc_fault;
+
+ mm = tsk->mm;
+ info.si_code = SEGV_MAPERR;
+
+ /*
+ * If we're in an interrupt or have no user
+ * context, we must not take the fault..
+ */
+ if (in_atomic() || !mm)
+ goto no_context;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, address);
+ if (!vma)
+ goto bad_area;
+ if (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto bad_area;
+
+ if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
+ /* accessing the stack below the stack pointer is always a
+ * bug */
+ if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) {
+#if 0
+ printk(KERN_WARNING
+ "[%d] ### Access below stack @%lx (sp=%lx)\n",
+ current->pid, address, regs->sp);
+ printk(KERN_WARNING
+ "vma [%08x - %08x]\n",
+ vma->vm_start, vma->vm_end);
+ show_registers(regs);
+ printk(KERN_WARNING
+ "[%d] ### Code: [%08lx]"
+ " %02x %02x %02x %02x %02x %02x %02x %02x\n",
+ current->pid,
+ regs->pc,
+ ((u8 *) regs->pc)[0],
+ ((u8 *) regs->pc)[1],
+ ((u8 *) regs->pc)[2],
+ ((u8 *) regs->pc)[3],
+ ((u8 *) regs->pc)[4],
+ ((u8 *) regs->pc)[5],
+ ((u8 *) regs->pc)[6],
+ ((u8 *) regs->pc)[7]
+ );
+#endif
+ 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:
+ info.si_code = SEGV_ACCERR;
+ write = 0;
+ switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) {
+ default: /* 3: write, present */
+ case MMUFCR_xFC_TYPE_WRITE:
+#ifdef TEST_VERIFY_AREA
+ if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
+ printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc);
+#endif
+ /* write to absent page */
+ case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE:
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ write++;
+ break;
+
+ /* read from protected page */
+ case MMUFCR_xFC_TYPE_READ:
+ goto bad_area;
+
+ /* read from absent page present */
+ case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ:
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto bad_area;
+ break;
+ }
+
+ /*
+ * 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, 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);
+ 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:
+ up_read(&mm->mmap_sem);
+
+ /* User mode accesses just cause a SIGSEGV */
+ if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void *)address;
+ force_sig_info(SIGSEGV, &info, tsk);
+ return;
+ }
+
+no_context:
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs))
+ return;
+
+/*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+
+ bust_spinlocks(1);
+
+ if (address < PAGE_SIZE)
+ printk(KERN_ALERT
+ "Unable to handle kernel NULL pointer dereference");
+ else
+ printk(KERN_ALERT
+ "Unable to handle kernel paging request");
+ printk(" at virtual address %08lx\n", address);
+ printk(" printing pc:\n");
+ printk(KERN_ALERT "%08lx\n", regs->pc);
+
+ debugger_intercept(fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR,
+ SIGSEGV, SEGV_ACCERR, regs);
+
+ page = PTBR;
+ page = ((unsigned long *) __va(page))[address >> 22];
+ printk(KERN_ALERT "*pde = %08lx\n", page);
+ if (page & 1) {
+ page &= PAGE_MASK;
+ address &= 0x003ff000;
+ page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
+ printk(KERN_ALERT "*pte = %08lx\n", page);
+ }
+
+ die("Oops", regs, fault_code);
+ do_exit(SIGKILL);
+
+/*
+ * 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);
+ printk(KERN_ALERT "VM: killing process %s\n", tsk->comm);
+ if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
+ do_exit(SIGKILL);
+ goto no_context;
+
+do_sigbus:
+ up_read(&mm->mmap_sem);
+
+ /*
+ * Send a sigbus, regardless of whether we were in kernel
+ * or user mode.
+ */
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = BUS_ADRERR;
+ info.si_addr = (void *)address;
+ force_sig_info(SIGBUS, &info, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
+ goto no_context;
+ return;
+
+vmalloc_fault:
+ {
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Do _not_ use "tsk" here. We might be inside
+ * an interrupt in the middle of a task switch..
+ */
+ int index = pgd_index(address);
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+ pte_t *pte_k;
+
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k))
+ goto no_context;
+
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ goto no_context;
+
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ goto no_context;
+
+ pgd = (pgd_t *) PTBR + index;
+ pud = pud_offset(pgd, address);
+ pmd = pmd_offset(pud, address);
+ set_pmd(pmd, *pmd_k);
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ goto no_context;
+ return;
+ }
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 02:35:17 +0000