Merge tag 'nds32-for-linus-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux

Pull nds32 architecture support from Greentime Hu:
 "This contains the core nds32 Linux port (including interrupt
  controller driver and timer driver), which has been through seven
  rounds of review on mailing list.

  It is able to boot to shell and passes most LTP-2017 testsuites in
  nds32 AE3XX platform:

    Total Tests: 1901
    Total Skipped Tests: 618
    Total Failures: 78"

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

* tag 'nds32-for-linus-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux: (44 commits)
  nds32: To use the generic dump_stack()
  nds32: fix building failed if using elf toolchain.
  nios2: add ioremap_nocache declaration before include asm-generic/io.h.
  nds32: fix building failed if using older version gcc.
  dt-bindings: timer: Add andestech atcpit100 timer binding doc
  clocksource/drivers/atcpit100: VDSO support
  clocksource/drivers/atcpit100: Add andestech atcpit100 timer
  net: faraday add nds32 support.
  irqchip: Andestech Internal Vector Interrupt Controller driver
  dt-bindings: interrupt-controller: Andestech Internal Vector Interrupt Controller
  dt-bindings: nds32 SoC Bindings
  dt-bindings: nds32 L2 cache controller Bindings
  dt-bindings: nds32 CPU Bindings
  MAINTAINERS: Add nds32
  nds32: Build infrastructure
  nds32: defconfig
  nds32: Miscellaneous header files
  nds32: Device tree support
  nds32: Generic timers support
  nds32: Loadable modules
  ...

1 files changed, 410 insertions, 0 deletions

diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c
new file mode 100644
index 000000000000..3a246fb8098c
--- /dev/null
+++ b/arch/nds32/mm/fault.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/extable.h>
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/ptrace.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+extern void die(const char *str, struct pt_regs *regs, long err);
+
+/*
+ * This is useful to dump out the page tables associated with
+ * 'addr' in mm 'mm'.
+ */
+void show_pte(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	if (!mm)
+		mm = &init_mm;
+
+	pr_alert("pgd = %p\n", mm->pgd);
+	pgd = pgd_offset(mm, addr);
+	pr_alert("[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
+
+	do {
+		pmd_t *pmd;
+
+		if (pgd_none(*pgd))
+			break;
+
+		if (pgd_bad(*pgd)) {
+			pr_alert("(bad)");
+			break;
+		}
+
+		pmd = pmd_offset(pgd, addr);
+#if PTRS_PER_PMD != 1
+		pr_alert(", *pmd=%08lx", pmd_val(*pmd));
+#endif
+
+		if (pmd_none(*pmd))
+			break;
+
+		if (pmd_bad(*pmd)) {
+			pr_alert("(bad)");
+			break;
+		}
+
+		if (IS_ENABLED(CONFIG_HIGHMEM))
+		{
+			pte_t *pte;
+			/* We must not map this if we have highmem enabled */
+			pte = pte_offset_map(pmd, addr);
+			pr_alert(", *pte=%08lx", pte_val(*pte));
+			pte_unmap(pte);
+		}
+	} while (0);
+
+	pr_alert("\n");
+}
+
+void do_page_fault(unsigned long entry, unsigned long addr,
+		   unsigned int error_code, struct pt_regs *regs)
+{
+	struct task_struct *tsk;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	siginfo_t info;
+	int fault;
+	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+	error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE);
+	tsk = current;
+	mm = tsk->mm;
+	info.si_code = SEGV_MAPERR;
+	/*
+	 * 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 (addr >= TASK_SIZE) {
+		if (user_mode(regs))
+			goto bad_area_nosemaphore;
+
+		if (addr >= TASK_SIZE && addr < VMALLOC_END
+		    && (entry == ENTRY_PTE_NOT_PRESENT))
+			goto vmalloc_fault;
+		else
+			goto no_context;
+	}
+
+	/* Send a signal to the task for handling the unalignment access. */
+	if (entry == ENTRY_GENERAL_EXCPETION
+	    && error_code == ETYPE_ALIGNMENT_CHECK) {
+		if (user_mode(regs))
+			goto bad_area_nosemaphore;
+		else
+			goto no_context;
+	}
+
+	/*
+	 * If we're in an interrupt or have no user
+	 * context, we must not take the fault..
+	 */
+	if (unlikely(faulthandler_disabled() || !mm))
+		goto no_context;
+
+	/*
+	 * As per x86, we may deadlock here. However, since the kernel only
+	 * validly references user space from well defined areas of the code,
+	 * we can bug out early if this is from code which shouldn't.
+	 */
+	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
+		if (!user_mode(regs) &&
+		    !search_exception_tables(instruction_pointer(regs)))
+			goto no_context;
+retry:
+		down_read(&mm->mmap_sem);
+	} else {
+		/*
+		 * The above down_read_trylock() might have succeeded in which
+		 * case, we'll have missed the might_sleep() from down_read().
+		 */
+		might_sleep();
+		if (IS_ENABLED(CONFIG_DEBUG_VM)) {
+			if (!user_mode(regs) &&
+			    !search_exception_tables(instruction_pointer(regs)))
+				goto no_context;
+		}
+	}
+
+	vma = find_vma(mm, addr);
+
+	if (unlikely(!vma))
+		goto bad_area;
+
+	if (vma->vm_start <= addr)
+		goto good_area;
+
+	if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
+		goto bad_area;
+
+	if (unlikely(expand_stack(vma, addr)))
+		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;
+
+	/* first do some preliminary protection checks */
+	if (entry == ENTRY_PTE_NOT_PRESENT) {
+		if (error_code & ITYPE_mskINST)
+			mask = VM_EXEC;
+		else {
+			mask = VM_READ | VM_WRITE;
+			if (vma->vm_flags & VM_WRITE)
+				flags |= FAULT_FLAG_WRITE;
+		}
+	} else if (entry == ENTRY_TLB_MISC) {
+		switch (error_code & ITYPE_mskETYPE) {
+		case RD_PROT:
+			mask = VM_READ;
+			break;
+		case WRT_PROT:
+			mask = VM_WRITE;
+			flags |= FAULT_FLAG_WRITE;
+			break;
+		case NOEXEC:
+			mask = VM_EXEC;
+			break;
+		case PAGE_MODIFY:
+			mask = VM_WRITE;
+			flags |= FAULT_FLAG_WRITE;
+			break;
+		case ACC_BIT:
+			BUG();
+		default:
+			break;
+		}
+
+	}
+	if (!(vma->vm_flags & mask))
+		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(vma, addr, flags);
+
+	/*
+	 * If we need to retry but a fatal signal is pending, handle the
+	 * signal first. We do not need to release the mmap_sem because it
+	 * would already be released in __lock_page_or_retry in mm/filemap.c.
+	 */
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
+		if (!user_mode(regs))
+			goto no_context;
+		return;
+	}
+
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		else
+			goto bad_area;
+	}
+
+	/*
+	 * Major/minor page fault accounting is only done on the initial
+	 * attempt. If we go through a retry, it is extremely likely that the
+	 * page will be found in page cache at that point.
+	 */
+	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;
+
+	/*
+	 * 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:
+
+	/* User mode accesses just cause a SIGSEGV */
+
+	if (user_mode(regs)) {
+		tsk->thread.address = addr;
+		tsk->thread.error_code = error_code;
+		tsk->thread.trap_no = entry;
+		info.si_signo = SIGSEGV;
+		info.si_errno = 0;
+		/* info.si_code has been set above */
+		info.si_addr = (void *)addr;
+		force_sig_info(SIGSEGV, &info, tsk);
+		return;
+	}
+
+no_context:
+
+	/* Are we prepared to handle this kernel fault?
+	 *
+	 * (The kernel has valid exception-points in the source
+	 *  when it acesses user-memory. When it fails in one
+	 *  of those points, we find it in a table and do a jump
+	 *  to some fixup code that loads an appropriate error
+	 *  code)
+	 */
+
+	{
+		const struct exception_table_entry *entry;
+
+		if ((entry =
+		     search_exception_tables(instruction_pointer(regs))) !=
+		    NULL) {
+			/* Adjust the instruction pointer in the stackframe */
+			instruction_pointer(regs) = entry->fixup;
+			return;
+		}
+	}
+
+	/*
+	 * Oops. The kernel tried to access some bad page. We'll have to
+	 * terminate things with extreme prejudice.
+	 */
+
+	bust_spinlocks(1);
+	pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
+		 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
+		 "paging request", addr);
+
+	show_pte(mm, addr);
+	die("Oops", regs, error_code);
+	bust_spinlocks(0);
+	do_exit(SIGKILL);
+
+	return;
+
+	/*
+	 * 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))
+		goto no_context;
+	pagefault_out_of_memory();
+	return;
+
+do_sigbus:
+	up_read(&mm->mmap_sem);
+
+	/* Kernel mode? Handle exceptions or die */
+	if (!user_mode(regs))
+		goto no_context;
+
+	/*
+	 * Send a sigbus
+	 */
+	tsk->thread.address = addr;
+	tsk->thread.error_code = error_code;
+	tsk->thread.trap_no = entry;
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = BUS_ADRERR;
+	info.si_addr = (void *)addr;
+	force_sig_info(SIGBUS, &info, tsk);
+
+	return;
+
+vmalloc_fault:
+	{
+		/*
+		 * Synchronize this task's top level page-table
+		 * with the 'reference' page table.
+		 *
+		 * Use current_pgd instead of tsk->active_mm->pgd
+		 * since the latter might be unavailable if this
+		 * code is executed in a misfortunately run irq
+		 * (like inside schedule() between switch_mm and
+		 *  switch_to...).
+		 */
+
+		unsigned int index = pgd_index(addr);
+		pgd_t *pgd, *pgd_k;
+		pud_t *pud, *pud_k;
+		pmd_t *pmd, *pmd_k;
+		pte_t *pte_k;
+
+		pgd = (pgd_t *) __va(__nds32__mfsr(NDS32_SR_L1_PPTB)) + index;
+		pgd_k = init_mm.pgd + index;
+
+		if (!pgd_present(*pgd_k))
+			goto no_context;
+
+		pud = pud_offset(pgd, addr);
+		pud_k = pud_offset(pgd_k, addr);
+		if (!pud_present(*pud_k))
+			goto no_context;
+
+		pmd = pmd_offset(pud, addr);
+		pmd_k = pmd_offset(pud_k, addr);
+		if (!pmd_present(*pmd_k))
+			goto no_context;
+
+		if (!pmd_present(*pmd))
+			set_pmd(pmd, *pmd_k);
+		else
+			BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
+
+		/*
+		 * Since the vmalloc area is global, we don't
+		 * need to copy individual PTE's, it is enough to
+		 * copy the pgd pointer into the pte page of the
+		 * root task. If that is there, we'll find our pte if
+		 * it exists.
+		 */
+
+		/* Make sure the actual PTE exists as well to
+		 * catch kernel vmalloc-area accesses to non-mapped
+		 * addres. If we don't do this, this will just
+		 * silently loop forever.
+		 */
+
+		pte_k = pte_offset_kernel(pmd_k, addr);
+		if (!pte_present(*pte_k))
+			goto no_context;
+
+		return;
+	}
+}