sh: Move in the SH-5 TLB miss.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

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..60d74f793a1
--- /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()) {
+		__typeof__(pte_val(__pte(0))) 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;
+}