diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 82e249f5639..8d425a72a0d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-22  Maciej W. Rozycki  <macro@mips.com>
+
+	* mips-linux-nat.c (mips64_linux_register_addr): Return -1 if
+	the width of the requested register exceeds the width of the
+	`ptrace' data type.
+
 2018-05-21  Tom Tromey  <tom@tromey.com>
 
 	* printcmd.c (output_command): Remove.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 3c554571fbe..c577b3d0562 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,10 @@
+2018-05-22  Maciej W. Rozycki  <macro@mips.com>
+
+	* linux-mips-low.c (mips_cannot_fetch_register): Return 1 if the
+	width of the requested register exceeds the width of the
+	`ptrace' data type.
+	(mips_cannot_store_register): Likewise.
+
 2018-05-21  Maciej W. Rozycki  <macro@mips.com>
 
 	* linux-mips-low.c (mips_fetch_register): New function.  Update
diff --git a/gdb/gdbserver/linux-mips-low.c b/gdb/gdbserver/linux-mips-low.c
index ff87dd77d37..7fae2e69844 100644
--- a/gdb/gdbserver/linux-mips-low.c
+++ b/gdb/gdbserver/linux-mips-low.c
@@ -211,6 +211,10 @@ mips_cannot_fetch_register (int regno)
 
   tdesc = current_process ()->tdesc;
 
+  /* On n32 we can't access 64-bit registers via PTRACE_PEEKUSR.  */
+  if (register_size (tdesc, regno) > sizeof (PTRACE_XFER_TYPE))
+    return 1;
+
   if (find_regno (tdesc, "r0") == regno)
     return 1;
 
@@ -227,6 +231,10 @@ mips_cannot_store_register (int regno)
 
   tdesc = current_process ()->tdesc;
 
+  /* On n32 we can't access 64-bit registers via PTRACE_POKEUSR.  */
+  if (register_size (tdesc, regno) > sizeof (PTRACE_XFER_TYPE))
+    return 1;
+
   if (find_regno (tdesc, "r0") == regno)
     return 1;
 
diff --git a/gdb/mips-linux-nat.c b/gdb/mips-linux-nat.c
index b1dbb798523..a9f0b790769 100644
--- a/gdb/mips-linux-nat.c
+++ b/gdb/mips-linux-nat.c
@@ -145,6 +145,11 @@ mips64_linux_register_addr (struct gdbarch *gdbarch, int regno, int store)
   if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
     error (_("Bogon register number %d."), regno);
 
+  /* On n32 we can't access 64-bit registers via PTRACE_PEEKUSR
+     or PTRACE_POKEUSR.  */
+  if (register_size (gdbarch, regno) > sizeof (PTRACE_TYPE_RET))
+    return (CORE_ADDR) -1;
+
   if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
     regaddr = regno;
   else if ((regno >= mips_regnum (gdbarch)->fp0)