v4.19.13 snapshot.
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
new file mode 100644
index 0000000..a9d55ad
--- /dev/null
+++ b/arch/ia64/mm/fault.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MMU fault handling support.
+ *
+ * Copyright (C) 1998-2002 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+#include <linux/sched/signal.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/extable.h>
+#include <linux/interrupt.h>
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/prefetch.h>
+#include <linux/uaccess.h>
+
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/exception.h>
+
+extern int die(char *, struct pt_regs *, long);
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+ int ret = 0;
+
+ if (!user_mode(regs)) {
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, trap))
+ ret = 1;
+ preempt_enable();
+ }
+
+ return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+ return 0;
+}
+#endif
+
+/*
+ * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
+ * (inside region 5, on ia64) and that page is present.
+ */
+static int
+mapped_kernel_page_is_present (unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *ptep, pte;
+
+ pgd = pgd_offset_k(address);
+ if (pgd_none(*pgd) || pgd_bad(*pgd))
+ return 0;
+
+ pud = pud_offset(pgd, address);
+ if (pud_none(*pud) || pud_bad(*pud))
+ return 0;
+
+ pmd = pmd_offset(pud, address);
+ if (pmd_none(*pmd) || pmd_bad(*pmd))
+ return 0;
+
+ ptep = pte_offset_kernel(pmd, address);
+ if (!ptep)
+ return 0;
+
+ pte = *ptep;
+ return pte_present(pte);
+}
+
+# define VM_READ_BIT 0
+# define VM_WRITE_BIT 1
+# define VM_EXEC_BIT 2
+
+void __kprobes
+ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
+{
+ int signal = SIGSEGV, code = SEGV_MAPERR;
+ struct vm_area_struct *vma, *prev_vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long mask;
+ vm_fault_t fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+ mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
+ | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
+
+ /* mmap_sem is performance critical.... */
+ prefetchw(&mm->mmap_sem);
+
+ /*
+ * If we're in an interrupt or have no user context, we must not take the fault..
+ */
+ if (faulthandler_disabled() || !mm)
+ goto no_context;
+
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+ /*
+ * If fault is in region 5 and we are in the kernel, we may already
+ * have the mmap_sem (pfn_valid macro is called during mmap). There
+ * is no vma for region 5 addr's anyway, so skip getting the semaphore
+ * and go directly to the exception handling code.
+ */
+
+ if ((REGION_NUMBER(address) == 5) && !user_mode(regs))
+ goto bad_area_no_up;
+#endif
+
+ /*
+ * This is to handle the kprobes on user space access instructions
+ */
+ if (notify_page_fault(regs, TRAP_BRKPT))
+ return;
+
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+ if (mask & VM_WRITE)
+ flags |= FAULT_FLAG_WRITE;
+retry:
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma_prev(mm, address, &prev_vma);
+ if (!vma && !prev_vma )
+ goto bad_area;
+
+ /*
+ * find_vma_prev() returns vma such that address < vma->vm_end or NULL
+ *
+ * May find no vma, but could be that the last vm area is the
+ * register backing store that needs to expand upwards, in
+ * this case vma will be null, but prev_vma will ne non-null
+ */
+ if (( !vma && prev_vma ) || (address < vma->vm_start) )
+ goto check_expansion;
+
+ good_area:
+ code = SEGV_ACCERR;
+
+ /* OK, we've got a good vm_area for this memory area. Check the access permissions: */
+
+# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
+ || (1 << VM_EXEC_BIT) != VM_EXEC)
+# error File is out of sync with <linux/mm.h>. Please update.
+# endif
+
+ if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
+ goto bad_area;
+
+ if ((vma->vm_flags & mask) != 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, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ /*
+ * We ran out of memory, or some other thing happened
+ * to us that made us unable to handle the page fault
+ * gracefully.
+ */
+ if (fault & VM_FAULT_OOM) {
+ goto out_of_memory;
+ } else if (fault & VM_FAULT_SIGSEGV) {
+ goto bad_area;
+ } else if (fault & VM_FAULT_SIGBUS) {
+ signal = SIGBUS;
+ goto bad_area;
+ }
+ BUG();
+ }
+
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->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;
+
+ check_expansion:
+ if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
+ if (!vma)
+ goto bad_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto bad_area;
+ if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
+ || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
+ goto bad_area;
+ if (expand_stack(vma, address))
+ goto bad_area;
+ } else {
+ vma = prev_vma;
+ if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
+ || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
+ goto bad_area;
+ /*
+ * Since the register backing store is accessed sequentially,
+ * we disallow growing it by more than a page at a time.
+ */
+ if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
+ goto bad_area;
+ if (expand_upwards(vma, address))
+ goto bad_area;
+ }
+ goto good_area;
+
+ bad_area:
+ up_read(&mm->mmap_sem);
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+ bad_area_no_up:
+#endif
+ if ((isr & IA64_ISR_SP)
+ || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
+ {
+ /*
+ * This fault was due to a speculative load or lfetch.fault, set the "ed"
+ * bit in the psr to ensure forward progress. (Target register will get a
+ * NaT for ld.s, lfetch will be canceled.)
+ */
+ ia64_psr(regs)->ed = 1;
+ return;
+ }
+ if (user_mode(regs)) {
+ struct siginfo si;
+
+ clear_siginfo(&si);
+ si.si_signo = signal;
+ si.si_errno = 0;
+ si.si_code = code;
+ si.si_addr = (void __user *) address;
+ si.si_isr = isr;
+ si.si_flags = __ISR_VALID;
+ force_sig_info(signal, &si, current);
+ return;
+ }
+
+ no_context:
+ if ((isr & IA64_ISR_SP)
+ || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
+ {
+ /*
+ * This fault was due to a speculative load or lfetch.fault, set the "ed"
+ * bit in the psr to ensure forward progress. (Target register will get a
+ * NaT for ld.s, lfetch will be canceled.)
+ */
+ ia64_psr(regs)->ed = 1;
+ return;
+ }
+
+ /*
+ * Since we have no vma's for region 5, we might get here even if the address is
+ * valid, due to the VHPT walker inserting a non present translation that becomes
+ * stale. If that happens, the non present fault handler already purged the stale
+ * translation, which fixed the problem. So, we check to see if the translation is
+ * valid, and return if it is.
+ */
+ if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
+ return;
+
+ if (ia64_done_with_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 (address < PAGE_SIZE)
+ printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
+ else
+ printk(KERN_ALERT "Unable to handle kernel paging request at "
+ "virtual address %016lx\n", address);
+ if (die("Oops", regs, isr))
+ regs = NULL;
+ bust_spinlocks(0);
+ if (regs)
+ do_exit(SIGKILL);
+ return;
+
+ out_of_memory:
+ up_read(&mm->mmap_sem);
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
+}