1 files changed, 30 insertions, 31 deletions

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 2d115016feb4..c8c61b1eb479 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -384,40 +384,31 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
 #define VM_FAULT_BADACCESS	0x020000
 
 static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
-			   unsigned int mm_flags, unsigned long vm_flags,
-			   struct task_struct *tsk)
+			   unsigned int mm_flags, unsigned long vm_flags)
 {
-	struct vm_area_struct *vma;
-	vm_fault_t fault;
+	struct vm_area_struct *vma = find_vma(mm, addr);
 
-	vma = find_vma(mm, addr);
-	fault = VM_FAULT_BADMAP;
 	if (unlikely(!vma))
-		goto out;
-	if (unlikely(vma->vm_start > addr))
-		goto check_stack;
+		return VM_FAULT_BADMAP;
 
 	/*
 	 * Ok, we have a good vm_area for this memory access, so we can handle
 	 * it.
 	 */
-good_area:
+	if (unlikely(vma->vm_start > addr)) {
+		if (!(vma->vm_flags & VM_GROWSDOWN))
+			return VM_FAULT_BADMAP;
+		if (expand_stack(vma, addr))
+			return VM_FAULT_BADMAP;
+	}
+
 	/*
 	 * Check that the permissions on the VMA allow for the fault which
 	 * occurred.
 	 */
-	if (!(vma->vm_flags & vm_flags)) {
-		fault = VM_FAULT_BADACCESS;
-		goto out;
-	}
-
+	if (!(vma->vm_flags & vm_flags))
+		return VM_FAULT_BADACCESS;
 	return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags);
-
-check_stack:
-	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
-		goto good_area;
-out:
-	return fault;
 }
 
 static bool is_el0_instruction_abort(unsigned int esr)
@@ -425,12 +416,20 @@ static bool is_el0_instruction_abort(unsigned int esr)
 	return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
 }
 
+/*
+ * Note: not valid for EL1 DC IVAC, but we never use that such that it
+ * should fault. EL0 cannot issue DC IVAC (undef).
+ */
+static bool is_write_abort(unsigned int esr)
+{
+	return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
+}
+
 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 				   struct pt_regs *regs)
 {
 	const struct fault_info *inf;
-	struct task_struct *tsk;
-	struct mm_struct *mm;
+	struct mm_struct *mm = current->mm;
 	vm_fault_t fault, major = 0;
 	unsigned long vm_flags = VM_READ | VM_WRITE;
 	unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
@@ -438,9 +437,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 	if (notify_page_fault(regs, esr))
 		return 0;
 
-	tsk = current;
-	mm  = tsk->mm;
-
 	/*
 	 * If we're in an interrupt or have no user context, we must not take
 	 * the fault.
@@ -453,7 +449,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 
 	if (is_el0_instruction_abort(esr)) {
 		vm_flags = VM_EXEC;
-	} else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
+		mm_flags |= FAULT_FLAG_INSTRUCTION;
+	} else if (is_write_abort(esr)) {
 		vm_flags = VM_WRITE;
 		mm_flags |= FAULT_FLAG_WRITE;
 	}
@@ -492,12 +489,14 @@ retry:
 		 */
 		might_sleep();
 #ifdef CONFIG_DEBUG_VM
-		if (!user_mode(regs) && !search_exception_tables(regs->pc))
+		if (!user_mode(regs) && !search_exception_tables(regs->pc)) {
+			up_read(&mm->mmap_sem);
 			goto no_context;
+		}
 #endif
 	}
 
-	fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk);
+	fault = __do_page_fault(mm, addr, mm_flags, vm_flags);
 	major |= fault & VM_FAULT_MAJOR;
 
 	if (fault & VM_FAULT_RETRY) {
@@ -537,11 +536,11 @@ retry:
 		 * that point.
 		 */
 		if (major) {
-			tsk->maj_flt++;
+			current->maj_flt++;
 			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
 				      addr);
 		} else {
-			tsk->min_flt++;
+			current->min_flt++;
 			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
 				      addr);
 		}