svn commit: r342552 - head/sys/arm64/arm64

[Andrew Turner]

Author: andrew
Date: Thu Dec 27 14:14:41 2018
New Revision: 342552
URL: https://svnweb.freebsd.org/changeset/base/342552

Log:
  Pass VM_PROT_EXECUTE to vm_fault for instruction faults.
  
  We need to tell vm_fault the reason for the fault was because we tried to
  execute from the memory location. Without this it may return with success
  as we only request read-only memory, then we return to the same location
  and try to execute from the same memory address. This leads to an infinite
  loop raising the same fault and returning to the same invalid location.
  
  MFC after:	1 week
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D18511

Modified:
  head/sys/arm64/arm64/trap.c

Modified: head/sys/arm64/arm64/trap.c
==============================================================================
--- head/sys/arm64/arm64/trap.c	Thu Dec 27 13:02:15 2018	(r342551)
+++ head/sys/arm64/arm64/trap.c	Thu Dec 27 14:14:41 2018	(r342552)
@@ -149,7 +149,7 @@ svc_handler(struct thread *td, struct trapframe *frame
 
 static void
 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
-    uint64_t far, int lower)
+    uint64_t far, int lower, int exec)
 {
 	struct vm_map *map;
 	struct proc *p;
@@ -229,6 +229,8 @@ no_pmap_fault:
 
 	va = trunc_page(far);
 	ftype = ((esr >> 6) & 1) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
+	if (exec)
+		ftype |= VM_PROT_EXECUTE;
 
 	/* Fault in the page. */
 	error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
@@ -336,7 +338,8 @@ do_el1h_sync(struct thread *td, struct trapframe *fram
 	case EXCP_DATA_ABORT:
 		far = READ_SPECIALREG(far_el1);
 		intr_enable();
-		data_abort(td, frame, esr, far, 0);
+		data_abort(td, frame, esr, far, 0,
+		    exception == EXCP_INSN_ABORT);
 		break;
 	case EXCP_BRK:
 #ifdef KDTRACE_HOOKS
@@ -433,7 +436,8 @@ do_el0_sync(struct thread *td, struct trapframe *frame
 	case EXCP_INSN_ABORT_L:
 	case EXCP_DATA_ABORT_L:
 	case EXCP_DATA_ABORT:
-		data_abort(td, frame, esr, far, 1);
+		data_abort(td, frame, esr, far, 1,
+		    exception == EXCP_INSN_ABORT_L);
 		break;
 	case EXCP_UNKNOWN:
 		if (!undef_insn(0, frame))