sh: Enable shared page fault handler for _32/_64.

This moves the now generic _32 page fault handling code to a shared place
and adapts the _64 implementation to make use of it.

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

1 files changed, 0 insertions, 564 deletions

diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
deleted file mode 100644
index 39e291c..0000000
--- a/arch/sh/mm/fault_32.c
+++ /dev/null
@@ -1,564 +0,0 @@
-/*
- * Page fault handler for SH with an MMU.
- *
- *  Copyright (C) 1999  Niibe Yutaka
- *  Copyright (C) 2003 - 2012  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 <linux/perf_event.h>
-#include <linux/kdebug.h>
-#include <asm/io_trapped.h>
-#include <asm/mmu_context.h>
-#include <asm/tlbflush.h>
-#include <asm/traps.h>
-
-static inline int notify_page_fault(struct pt_regs *regs, int trap)
-{
-	int ret = 0;
-
-	if (kprobes_built_in() && !user_mode(regs)) {
-		preempt_disable();
-		if (kprobe_running() && kprobe_fault_handler(regs, trap))
-			ret = 1;
-		preempt_enable();
-	}
-
-	return ret;
-}
-
-static void
-force_sig_info_fault(int si_signo, int si_code, unsigned long address,
-		     struct task_struct *tsk)
-{
-	siginfo_t info;
-
-	info.si_signo	= si_signo;
-	info.si_errno	= 0;
-	info.si_code	= si_code;
-	info.si_addr	= (void __user *)address;
-
-	force_sig_info(si_signo, &info, tsk);
-}
-
-/*
- * This is useful to dump out the page tables associated with
- * 'addr' in mm 'mm'.
- */
-static void show_pte(struct mm_struct *mm, unsigned long addr)
-{
-	pgd_t *pgd;
-
-	if (mm)
-		pgd = mm->pgd;
-	else
-		pgd = get_TTB();
-
-	printk(KERN_ALERT "pgd = %p\n", pgd);
-	pgd += pgd_index(addr);
-	printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
-	       sizeof(*pgd) * 2, (u64)pgd_val(*pgd));
-
-	do {
-		pud_t *pud;
-		pmd_t *pmd;
-		pte_t *pte;
-
-		if (pgd_none(*pgd))
-			break;
-
-		if (pgd_bad(*pgd)) {
-			printk("(bad)");
-			break;
-		}
-
-		pud = pud_offset(pgd, addr);
-		if (PTRS_PER_PUD != 1)
-			printk(", *pud=%0*Lx", sizeof(*pud) * 2,
-			       (u64)pud_val(*pud));
-
-		if (pud_none(*pud))
-			break;
-
-		if (pud_bad(*pud)) {
-			printk("(bad)");
-			break;
-		}
-
-		pmd = pmd_offset(pud, addr);
-		if (PTRS_PER_PMD != 1)
-			printk(", *pmd=%0*Lx", sizeof(*pmd) * 2,
-			       (u64)pmd_val(*pmd));
-
-		if (pmd_none(*pmd))
-			break;
-
-		if (pmd_bad(*pmd)) {
-			printk("(bad)");
-			break;
-		}
-
-		/* We must not map this if we have highmem enabled */
-		if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
-			break;
-
-		pte = pte_offset_kernel(pmd, addr);
-		printk(", *pte=%0*Lx", sizeof(*pte) * 2, (u64)pte_val(*pte));
-	} while (0);
-
-	printk("\n");
-}
-
-static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
-{
-	unsigned index = pgd_index(address);
-	pgd_t *pgd_k;
-	pud_t *pud, *pud_k;
-	pmd_t *pmd, *pmd_k;
-
-	pgd += index;
-	pgd_k = init_mm.pgd + index;
-
-	if (!pgd_present(*pgd_k))
-		return NULL;
-
-	pud = pud_offset(pgd, address);
-	pud_k = pud_offset(pgd_k, address);
-	if (!pud_present(*pud_k))
-		return NULL;
-
-	if (!pud_present(*pud))
-	    set_pud(pud, *pud_k);
-
-	pmd = pmd_offset(pud, address);
-	pmd_k = pmd_offset(pud_k, address);
-	if (!pmd_present(*pmd_k))
-		return NULL;
-
-	if (!pmd_present(*pmd))
-		set_pmd(pmd, *pmd_k);
-	else {
-		/*
-		 * The page tables are fully synchronised so there must
-		 * be another reason for the fault. Return NULL here to
-		 * signal that we have not taken care of the fault.
-		 */
-		BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
-		return NULL;
-	}
-
-	return pmd_k;
-}
-
-/*
- * Handle a fault on the vmalloc or module mapping area
- */
-static noinline int vmalloc_fault(unsigned long address)
-{
-	pgd_t *pgd_k;
-	pmd_t *pmd_k;
-	pte_t *pte_k;
-
-	/* Make sure we are in vmalloc/module area: */
-	if (!is_vmalloc_addr((void *)address))
-		return -1;
-
-	/*
-	 * Synchronize this task's top level page-table
-	 * with the 'reference' page table.
-	 *
-	 * Do _not_ use "current" here. We might be inside
-	 * an interrupt in the middle of a task switch..
-	 */
-	pgd_k = get_TTB();
-	pmd_k = vmalloc_sync_one(pgd_k, address);
-	if (!pmd_k)
-		return -1;
-
-	pte_k = pte_offset_kernel(pmd_k, address);
-	if (!pte_present(*pte_k))
-		return -1;
-
-	return 0;
-}
-
-static void
-show_fault_oops(struct pt_regs *regs, unsigned long address)
-{
-	if (!oops_may_print())
-		return;
-
-	printk(KERN_ALERT "BUG: unable to handle kernel ");
-	if (address < PAGE_SIZE)
-		printk(KERN_CONT "NULL pointer dereference");
-	else
-		printk(KERN_CONT "paging request");
-
-	printk(KERN_CONT " at %08lx\n", address);
-	printk(KERN_ALERT "PC:");
-	printk_address(regs->pc, 1);
-
-	show_pte(NULL, address);
-}
-
-static noinline void
-no_context(struct pt_regs *regs, unsigned long error_code,
-	   unsigned long address)
-{
-	/* Are we prepared to handle this kernel fault?  */
-	if (fixup_exception(regs))
-		return;
-
-	if (handle_trapped_io(regs, address))
-		return;
-
-	/*
-	 * Oops. The kernel tried to access some bad page. We'll have to
-	 * terminate things with extreme prejudice.
-	 */
-	bust_spinlocks(1);
-
-	show_fault_oops(regs, address);
-
-	die("Oops", regs, error_code);
-	bust_spinlocks(0);
-	do_exit(SIGKILL);
-}
-
-static void
-__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
-		       unsigned long address, int si_code)
-{
-	struct task_struct *tsk = current;
-
-	/* User mode accesses just cause a SIGSEGV */
-	if (user_mode(regs)) {
-		/*
-		 * It's possible to have interrupts off here:
-		 */
-		local_irq_enable();
-
-		force_sig_info_fault(SIGSEGV, si_code, address, tsk);
-
-		return;
-	}
-
-	no_context(regs, error_code, address);
-}
-
-static noinline void
-bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
-		     unsigned long address)
-{
-	__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
-}
-
-static void
-__bad_area(struct pt_regs *regs, unsigned long error_code,
-	   unsigned long address, int si_code)
-{
-	struct mm_struct *mm = current->mm;
-
-	/*
-	 * Something tried to access memory that isn't in our memory map..
-	 * Fix it, but check if it's kernel or user first..
-	 */
-	up_read(&mm->mmap_sem);
-
-	__bad_area_nosemaphore(regs, error_code, address, si_code);
-}
-
-static noinline void
-bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
-{
-	__bad_area(regs, error_code, address, SEGV_MAPERR);
-}
-
-static noinline void
-bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
-		      unsigned long address)
-{
-	__bad_area(regs, error_code, address, SEGV_ACCERR);
-}
-
-static void out_of_memory(void)
-{
-	/*
-	 * We ran out of memory, call the OOM killer, and return the userspace
-	 * (which will retry the fault, or kill us if we got oom-killed):
-	 */
-	up_read(&current->mm->mmap_sem);
-
-	pagefault_out_of_memory();
-}
-
-static void
-do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
-{
-	struct task_struct *tsk = current;
-	struct mm_struct *mm = tsk->mm;
-
-	up_read(&mm->mmap_sem);
-
-	/* Kernel mode? Handle exceptions or die: */
-	if (!user_mode(regs))
-		no_context(regs, error_code, address);
-
-	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
-}
-
-static noinline int
-mm_fault_error(struct pt_regs *regs, unsigned long error_code,
-	       unsigned long address, unsigned int fault)
-{
-	/*
-	 * Pagefault was interrupted by SIGKILL. We have no reason to
-	 * continue pagefault.
-	 */
-	if (fatal_signal_pending(current)) {
-		if (!(fault & VM_FAULT_RETRY))
-			up_read(&current->mm->mmap_sem);
-		if (!user_mode(regs))
-			no_context(regs, error_code, address);
-		return 1;
-	}
-
-	if (!(fault & VM_FAULT_ERROR))
-		return 0;
-
-	if (fault & VM_FAULT_OOM) {
-		/* Kernel mode? Handle exceptions or die: */
-		if (!user_mode(regs)) {
-			up_read(&current->mm->mmap_sem);
-			no_context(regs, error_code, address);
-			return 1;
-		}
-
-		out_of_memory();
-	} else {
-		if (fault & VM_FAULT_SIGBUS)
-			do_sigbus(regs, error_code, address);
-		else
-			BUG();
-	}
-
-	return 1;
-}
-
-static inline int access_error(int write, struct vm_area_struct *vma)
-{
-	if (write) {
-		/* write, present and write, not present: */
-		if (unlikely(!(vma->vm_flags & VM_WRITE)))
-			return 1;
-		return 0;
-	}
-
-	/* read, not present: */
-	if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
-		return 1;
-
-	return 0;
-}
-
-static int fault_in_kernel_space(unsigned long address)
-{
-	return address >= TASK_SIZE;
-}
-
-/*
- * 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 error_code,
-					unsigned long address)
-{
-	unsigned long vec;
-	struct task_struct *tsk;
-	struct mm_struct *mm;
-	struct vm_area_struct * vma;
-	int fault;
-	int write = error_code & FAULT_CODE_WRITE;
-	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
-			      (write ? FAULT_FLAG_WRITE : 0));
-
-	tsk = current;
-	mm = tsk->mm;
-	vec = lookup_exception_vector();
-
-	/*
-	 * 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.
-	 */
-	if (unlikely(fault_in_kernel_space(address))) {
-		if (vmalloc_fault(address) >= 0)
-			return;
-		if (notify_page_fault(regs, vec))
-			return;
-
-		bad_area_nosemaphore(regs, error_code, address);
-		return;
-	}
-
-	if (unlikely(notify_page_fault(regs, vec)))
-		return;
-
-	/* Only enable interrupts if they were on before the fault */
-	if ((regs->sr & SR_IMASK) != SR_IMASK)
-		local_irq_enable();
-
-	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-
-	/*
-	 * If we're in an interrupt, have no user context or are running
-	 * in an atomic region then we must not take the fault:
-	 */
-	if (unlikely(in_atomic() || !mm)) {
-		bad_area_nosemaphore(regs, error_code, address);
-		return;
-	}
-
-retry:
-	down_read(&mm->mmap_sem);
-
-	vma = find_vma(mm, address);
-	if (unlikely(!vma)) {
-		bad_area(regs, error_code, address);
-		return;
-	}
-	if (likely(vma->vm_start <= address))
-		goto good_area;
-	if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
-		bad_area(regs, error_code, address);
-		return;
-	}
-	if (unlikely(expand_stack(vma, address))) {
-		bad_area(regs, error_code, address);
-		return;
-	}
-
-	/*
-	 * Ok, we have a good vm_area for this memory access, so
-	 * we can handle it..
-	 */
-good_area:
-	if (unlikely(access_error(error_code, vma))) {
-		bad_area_access_error(regs, error_code, address);
-		return;
-	}
-
-	set_thread_fault_code(error_code);
-
-	/*
-	 * 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 (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
-		if (mm_fault_error(regs, error_code, address, fault))
-			return;
-
-	if (flags & FAULT_FLAG_ALLOW_RETRY) {
-		if (fault & VM_FAULT_MAJOR) {
-			tsk->maj_flt++;
-			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
-				      regs, address);
-		} else {
-			tsk->min_flt++;
-			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
-				      regs, address);
-		}
-		if (fault & VM_FAULT_RETRY) {
-			flags &= ~FAULT_FLAG_ALLOW_RETRY;
-
-			/*
-			 * 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);
-}
-
-/*
- * Called with interrupts disabled.
- */
-asmlinkage int __kprobes
-handle_tlbmiss(struct pt_regs *regs, unsigned long error_code,
-	       unsigned long address)
-{
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-	pte_t entry;
-
-	/*
-	 * 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(error_code && !pte_write(entry)))
-		return 1;
-
-	if (error_code)
-		entry = pte_mkdirty(entry);
-	entry = pte_mkyoung(entry);
-
-	set_pte(pte, entry);
-
-#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
-	/*
-	 * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
-	 * the case of an initial page write exception, so we need to
-	 * flush it in order to avoid potential TLB entry duplication.
-	 */
-	if (error_code == FAULT_CODE_INITIAL)
-		local_flush_tlb_one(get_asid(), address & PAGE_MASK);
-#endif
-
-	set_thread_fault_code(error_code);
-	update_mmu_cache(NULL, address, pte);
-
-	return 0;
-}