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-rw-r--r--arch/metag/mm/fault.c239
1 files changed, 239 insertions, 0 deletions
diff --git a/arch/metag/mm/fault.c b/arch/metag/mm/fault.c
new file mode 100644
index 00000000000..2c75bf7357c
--- /dev/null
+++ b/arch/metag/mm/fault.c
@@ -0,0 +1,239 @@
+/*
+ * Meta page fault handling.
+ *
+ * Copyright (C) 2005-2012 Imagination Technologies Ltd.
+ */
+
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/interrupt.h>
+#include <linux/uaccess.h>
+
+#include <asm/tlbflush.h>
+#include <asm/mmu.h>
+#include <asm/traps.h>
+
+/* Clear any pending catch buffer state. */
+static void clear_cbuf_entry(struct pt_regs *regs, unsigned long addr,
+ unsigned int trapno)
+{
+ PTBICTXEXTCB0 cbuf = regs->extcb0;
+
+ switch (trapno) {
+ /* Instruction fetch faults leave no catch buffer state. */
+ case TBIXXF_SIGNUM_IGF:
+ case TBIXXF_SIGNUM_IPF:
+ return;
+ default:
+ if (cbuf[0].CBAddr == addr) {
+ cbuf[0].CBAddr = 0;
+ cbuf[0].CBFlags &= ~TXCATCH0_FAULT_BITS;
+
+ /* And, as this is the ONLY catch entry, we
+ * need to clear the cbuf bit from the context!
+ */
+ regs->ctx.SaveMask &= ~(TBICTX_CBUF_BIT |
+ TBICTX_XCBF_BIT);
+
+ return;
+ }
+ pr_err("Failed to clear cbuf entry!\n");
+ }
+}
+
+int show_unhandled_signals = 1;
+
+int do_page_fault(struct pt_regs *regs, unsigned long address,
+ unsigned int write_access, unsigned int trapno)
+{
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct *vma, *prev_vma;
+ siginfo_t info;
+ int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (write_access ? FAULT_FLAG_WRITE : 0);
+
+ tsk = current;
+
+ if ((address >= VMALLOC_START) && (address < VMALLOC_END)) {
+ /*
+ * 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;
+ pte_t *pte_k;
+
+ pgd = ((pgd_t *)mmu_get_base()) + 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 0;
+ }
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!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_k))
+ goto bad_area_nosemaphore;
+ set_pmd(pmd, *pmd_k);
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ goto bad_area_nosemaphore;
+
+ /* May only be needed on Chorus2 */
+ flush_tlb_all();
+ return 0;
+ }
+
+ mm = tsk->mm;
+
+ if (in_atomic() || !mm)
+ goto no_context;
+
+retry:
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma_prev(mm, address, &prev_vma);
+
+ if (!vma || address < vma->vm_start)
+ goto check_expansion;
+
+good_area:
+ if (write_access) {
+ 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.
+ */
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return 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 (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+ 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);
+ return 0;
+
+check_expansion:
+ vma = prev_vma;
+ if (vma && (expand_stack(vma, address) == 0))
+ goto good_area;
+
+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 = SEGV_MAPERR;
+ info.si_addr = (__force void __user *)address;
+ info.si_trapno = trapno;
+
+ if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+ printk_ratelimit()) {
+ pr_info("%s%s[%d]: segfault at %lx pc %08x sp %08x write %d trap %#x (%s)",
+ task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+ tsk->comm, task_pid_nr(tsk), address,
+ regs->ctx.CurrPC, regs->ctx.AX[0].U0,
+ write_access, trapno, trap_name(trapno));
+ print_vma_addr(" in ", regs->ctx.CurrPC);
+ print_vma_addr(" rtp in ", regs->ctx.DX[4].U1);
+ printk("\n");
+ show_regs(regs);
+ }
+ force_sig_info(SIGSEGV, &info, tsk);
+ return 1;
+ }
+ 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 = (__force void __user *)address;
+ info.si_trapno = trapno;
+ force_sig_info(SIGBUS, &info, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (!user_mode(regs))
+ goto no_context;
+
+ return 1;
+
+ /*
+ * 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 (user_mode(regs))
+ do_group_exit(SIGKILL);
+
+no_context:
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs)) {
+ clear_cbuf_entry(regs, address, trapno);
+ return 1;
+ }
+
+ die("Oops", regs, (write_access << 15) | trapno, address);
+ do_exit(SIGKILL);
+}