v4.19.13 snapshot.
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
new file mode 100644
index 0000000..db69130
--- /dev/null
+++ b/arch/arc/mm/fault.c
@@ -0,0 +1,246 @@
+/* Page Fault Handling for ARC (TLB Miss / ProtV)
+ *
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/signal.h>
+#include <linux/interrupt.h>
+#include <linux/sched/signal.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+#include <linux/kdebug.h>
+#include <linux/perf_event.h>
+#include <linux/mm_types.h>
+#include <asm/pgalloc.h>
+#include <asm/mmu.h>
+
+/*
+ * kernel virtual address is required to implement vmalloc/pkmap/fixmap
+ * Refer to asm/processor.h for System Memory Map
+ *
+ * It simply copies the PMD entry (pointer to 2nd level page table or hugepage)
+ * from swapper pgdir to task pgdir. The 2nd level table/page is thus shared
+ */
+noinline static int handle_kernel_vaddr_fault(unsigned long address)
+{
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ */
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd = pgd_offset_fast(current->active_mm, address);
+ pgd_k = pgd_offset_k(address);
+
+ if (!pgd_present(*pgd_k))
+ goto bad_area;
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ goto bad_area;
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ goto bad_area;
+
+ set_pmd(pmd, *pmd_k);
+
+ /* XXX: create the TLB entry here */
+ return 0;
+
+bad_area:
+ return 1;
+}
+
+void do_page_fault(unsigned long address, struct pt_regs *regs)
+{
+ struct vm_area_struct *vma = NULL;
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+ siginfo_t info;
+ int ret;
+ vm_fault_t fault;
+ int write = regs->ecr_cause & ECR_C_PROTV_STORE; /* ST/EX */
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+ clear_siginfo(&info);
+
+ /*
+ * 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 (address >= VMALLOC_START) {
+ ret = handle_kernel_vaddr_fault(address);
+ if (unlikely(ret))
+ goto bad_area_nosemaphore;
+ else
+ return;
+ }
+
+ info.si_code = SEGV_MAPERR;
+
+ /*
+ * If we're in an interrupt or have no user
+ * context, we must not take the fault..
+ */
+ if (faulthandler_disabled() || !mm)
+ goto no_context;
+
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+retry:
+ 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:
+ info.si_code = SEGV_ACCERR;
+
+ /* Handle protection violation, execute on heap or stack */
+
+ if ((regs->ecr_vec == ECR_V_PROTV) &&
+ (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
+ goto bad_area;
+
+ if (write) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ flags |= FAULT_FLAG_WRITE;
+ } else {
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ 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, address, flags);
+
+ /* If Pagefault was interrupted by SIGKILL, exit page fault "early" */
+ if (unlikely(fatal_signal_pending(current))) {
+ if ((fault & VM_FAULT_ERROR) && !(fault & VM_FAULT_RETRY))
+ up_read(&mm->mmap_sem);
+ if (user_mode(regs))
+ return;
+ }
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+ if (likely(!(fault & VM_FAULT_ERROR))) {
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ /* To avoid updating stats twice for retry case */
+ 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;
+ flags |= FAULT_FLAG_TRIED;
+ goto retry;
+ }
+ }
+
+ /* Fault Handled Gracefully */
+ up_read(&mm->mmap_sem);
+ return;
+ }
+
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGSEGV)
+ goto bad_area;
+ else if (fault & VM_FAULT_SIGBUS)
+ goto do_sigbus;
+
+ /* no man's land */
+ BUG();
+
+ /*
+ * 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.fault_address = address;
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void __user *)address;
+ 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 accesses 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)
+ */
+ if (fixup_exception(regs))
+ return;
+
+ die("Oops", regs, address);
+
+out_of_memory:
+ up_read(&mm->mmap_sem);
+
+ if (user_mode(regs)) {
+ pagefault_out_of_memory();
+ return;
+ }
+
+ goto no_context;
+
+do_sigbus:
+ up_read(&mm->mmap_sem);
+
+ if (!user_mode(regs))
+ goto no_context;
+
+ tsk->thread.fault_address = address;
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = BUS_ADRERR;
+ info.si_addr = (void __user *)address;
+ force_sig_info(SIGBUS, &info, tsk);
+}