aboutsummaryrefslogtreecommitdiff
path: root/arch/sh/mm/fault_32.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sh/mm/fault_32.c')
-rw-r--r--arch/sh/mm/fault_32.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
new file mode 100644
index 00000000000..33b43d20e9f
--- /dev/null
+++ b/arch/sh/mm/fault_32.c
@@ -0,0 +1,303 @@
+/*
+ * Page fault handler for SH with an MMU.
+ *
+ * Copyright (C) 1999 Niibe Yutaka
+ * Copyright (C) 2003 - 2007 Paul Mundt
+ *
+ * Based on linux/arch/i386/mm/fault.c:
+ * Copyright (C) 1995 Linus Torvalds
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <asm/system.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/kgdb.h>
+
+/*
+ * This routine handles page faults. It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ */
+asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
+ unsigned long writeaccess,
+ unsigned long address)
+{
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct * vma;
+ int si_code;
+ int fault;
+ siginfo_t info;
+
+ trace_hardirqs_on();
+ local_irq_enable();
+
+#ifdef CONFIG_SH_KGDB
+ if (kgdb_nofault && kgdb_bus_err_hook)
+ kgdb_bus_err_hook();
+#endif
+
+ tsk = current;
+ mm = tsk->mm;
+ si_code = SEGV_MAPERR;
+
+ if (unlikely(address >= TASK_SIZE)) {
+ /*
+ * 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 offset = pgd_index(address);
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd = get_TTB() + offset;
+ pgd_k = swapper_pg_dir + offset;
+
+ /* This will never happen with the folded page table. */
+ if (!pgd_present(*pgd)) {
+ if (!pgd_present(*pgd_k))
+ goto bad_area_nosemaphore;
+ set_pgd(pgd, *pgd_k);
+ return;
+ }
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (pud_present(*pud) || !pud_present(*pud_k))
+ goto bad_area_nosemaphore;
+ set_pud(pud, *pud_k);
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (pmd_present(*pmd) || !pmd_present(*pmd_k))
+ goto bad_area_nosemaphore;
+ set_pmd(pmd, *pmd_k);
+
+ return;
+ }
+
+ /*
+ * 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 (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 (writeaccess) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ } else {
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
+ 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.
+ */
+survive:
+ fault = handle_mm_fault(mm, vma, address, writeaccess);
+ 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)
+ tsk->maj_flt++;
+ else
+ tsk->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);
+
+bad_area_nosemaphore:
+ if (user_mode(regs)) {
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ info.si_code = si_code;
+ 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 (oops_may_print()) {
+ unsigned long page;
+
+ 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(KERN_ALERT "pc = %08lx\n", regs->pc);
+ page = (unsigned long)get_TTB();
+ if (page) {
+ page = ((__typeof__(page) *)page)[address >> PGDIR_SHIFT];
+ printk(KERN_ALERT "*pde = %08lx\n", page);
+ if (page & _PAGE_PRESENT) {
+ page &= PAGE_MASK;
+ address &= 0x003ff000;
+ page = ((__typeof__(page) *)
+ __va(page))[address >>
+ PAGE_SHIFT];
+ printk(KERN_ALERT "*pte = %08lx\n", page);
+ }
+ }
+ }
+
+ die("Oops", regs, writeaccess);
+ bust_spinlocks(0);
+ 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);
+ if (is_global_init(current)) {
+ yield();
+ down_read(&mm->mmap_sem);
+ goto survive;
+ }
+ printk("VM: killing process %s\n", tsk->comm);
+ if (user_mode(regs))
+ do_group_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 (!user_mode(regs))
+ goto no_context;
+}
+
+#ifdef CONFIG_SH_STORE_QUEUES
+/*
+ * This is a special case for the SH-4 store queues, as pages for this
+ * space still need to be faulted in before it's possible to flush the
+ * store queue cache for writeout to the remapped region.
+ */
+#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000)
+#else
+#define P3_ADDR_MAX P4SEG
+#endif
+
+/*
+ * Called with interrupts disabled.
+ */
+asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
+ unsigned long writeaccess,
+ unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ pte_t entry;
+
+#ifdef CONFIG_SH_KGDB
+ if (kgdb_nofault && kgdb_bus_err_hook)
+ kgdb_bus_err_hook();
+#endif
+
+ /*
+ * We don't take page faults for P1, P2, and parts of P4, these
+ * are always mapped, whether it be due to legacy behaviour in
+ * 29-bit mode, or due to PMB configuration in 32-bit mode.
+ */
+ if (address >= P3SEG && address < P3_ADDR_MAX) {
+ pgd = pgd_offset_k(address);
+ } else {
+ if (unlikely(address >= TASK_SIZE || !current->mm))
+ return 1;
+
+ pgd = pgd_offset(current->mm, address);
+ }
+
+ pud = pud_offset(pgd, address);
+ if (pud_none_or_clear_bad(pud))
+ return 1;
+ pmd = pmd_offset(pud, address);
+ if (pmd_none_or_clear_bad(pmd))
+ return 1;
+
+ pte = pte_offset_kernel(pmd, address);
+ entry = *pte;
+ if (unlikely(pte_none(entry) || pte_not_present(entry)))
+ return 1;
+ if (unlikely(writeaccess && !pte_write(entry)))
+ return 1;
+
+ if (writeaccess)
+ entry = pte_mkdirty(entry);
+ entry = pte_mkyoung(entry);
+
+ set_pte(pte, entry);
+ update_mmu_cache(NULL, address, entry);
+
+ return 0;
+}