gdb: Consolidate 32bit-pkeys.xml and 64bit-pkeys.xml

1. Since 32bit-pkeys.xml and 64bit-pkeys.xml are identical, consolidate
them into a single keys.xml.
2. Enable PKU for x32 to fix:

$ gdbserver :123456 x32-program
...
.../gdbserver/regcache.cc:255: A problem internal to GDBserver has been detected
.
Unknown register pkru requested

on Tiger Lake.

gdb/amd64-linux-tdep.c

@@ -1578,14 +1578,16 @@ amd64_linux_read_description (uint64_t xcr0_features_bit, bool is_x32)
 {
   static target_desc *amd64_linux_tdescs \
     [2/*AVX*/][2/*MPX*/][2/*AVX512*/][2/*PKRU*/] = {};
-  static target_desc *x32_linux_tdescs[2/*AVX*/][2/*AVX512*/] = {};
+  static target_desc *x32_linux_tdescs \
+    [2/*AVX*/][2/*AVX512*/][2/*PKRU*/] = {};
 
   target_desc **tdesc;
 
   if (is_x32)
     {
       tdesc = &x32_linux_tdescs[(xcr0_features_bit & X86_XSTATE_AVX) ? 1 : 0 ]
-	[(xcr0_features_bit & X86_XSTATE_AVX512) ? 1 : 0];
+	[(xcr0_features_bit & X86_XSTATE_AVX512) ? 1 : 0]
+	[(xcr0_features_bit & X86_XSTATE_PKRU) ? 1 : 0];
     }
   else
     {

gdb/arch/amd64.c

@@ -25,9 +25,9 @@
 #include "../features/i386/64bit-core.c"
 #include "../features/i386/64bit-linux.c"
 #include "../features/i386/64bit-mpx.c"
-#include "../features/i386/64bit-pkeys.c"
 #include "../features/i386/64bit-segments.c"
 #include "../features/i386/64bit-sse.c"
+#include "../features/i386/pkeys.c"
 
 #include "../features/i386/x32-core.c"
 
@@ -72,8 +72,8 @@ amd64_create_target_description (uint64_t xcr0, bool is_x32, bool is_linux,
   if (xcr0 & X86_XSTATE_AVX512)
     regnum = create_feature_i386_64bit_avx512 (tdesc.get (), regnum);
 
-  if ((xcr0 & X86_XSTATE_PKRU) && !is_x32)
-    regnum = create_feature_i386_64bit_pkeys (tdesc.get (), regnum);
+  if (xcr0 & X86_XSTATE_PKRU)
+    regnum = create_feature_i386_pkeys (tdesc.get (), regnum);
 
   return tdesc.release ();
 }

gdb/arch/i386.c

@@ -27,8 +27,8 @@
 #include "../features/i386/32bit-avx.c"
 #include "../features/i386/32bit-avx512.c"
 #include "../features/i386/32bit-mpx.c"
-#include "../features/i386/32bit-pkeys.c"
 #include "../features/i386/32bit-segments.c"
+#include "../features/i386/pkeys.c"
 
 /* Create i386 target descriptions according to XCR0.  */
 
@@ -67,7 +67,7 @@ i386_create_target_description (uint64_t xcr0, bool is_linux, bool segments)
     regnum = create_feature_i386_32bit_avx512 (tdesc.get (), regnum);
 
   if (xcr0 & X86_XSTATE_PKRU)
-    regnum = create_feature_i386_32bit_pkeys (tdesc.get (), regnum);
+    regnum = create_feature_i386_pkeys (tdesc.get (), regnum);
 
   return tdesc.release ();
 }

gdb/features/Makefile

@@ -216,7 +216,6 @@ FEATURE_XMLFILES = aarch64-core.xml \
 	i386/32bit-avx.xml \
 	i386/32bit-mpx.xml \
 	i386/32bit-avx512.xml \
-	i386/32bit-pkeys.xml \
 	i386/32bit-segments.xml \
 	i386/64bit-avx512.xml \
 	i386/64bit-core.xml \
@@ -224,8 +223,8 @@ FEATURE_XMLFILES = aarch64-core.xml \
 	i386/64bit-segments.xml \
 	i386/64bit-avx.xml \
 	i386/64bit-linux.xml \
-	i386/64bit-pkeys.xml \
 	i386/64bit-sse.xml \
+	i386/pkeys.xml \
 	i386/x32-core.xml \
 	loongarch/base32.xml \
 	loongarch/base64.xml \

gdb/features/i386/64bit-pkeys.c

@@ -1,14 +0,0 @@
-/* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
-  Original: 64bit-pkeys.xml */
-
-#include "gdbsupport/tdesc.h"
-
-static int
-create_feature_i386_64bit_pkeys (struct target_desc *result, long regnum)
-{
-  struct tdesc_feature *feature;
-
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.pkeys");
-  tdesc_create_reg (feature, "pkru", regnum++, 1, NULL, 32, "uint32");
-  return regnum;
-}

gdb/features/i386/64bit-pkeys.xml

@@ -1,13 +0,0 @@
-<?xml version="1.0"?>
-<!-- Copyright (C) 2016-2022 Free Software Foundation, Inc.
-
-     Copying and distribution of this file, with or without modification,
-     are permitted in any medium without royalty provided the copyright
-     notice and this notice are preserved.  -->
-
-<!DOCTYPE feature SYSTEM "gdb-target.dtd">
-<feature name="org.gnu.gdb.i386.pkeys">
-
-  <reg name="pkru" bitsize="32" type="uint32"/>
-
-</feature>

gdb/features/i386/32bit-pkeys.c → gdb/features/i386/pkeys.c

@@ -1,10 +1,10 @@
 /* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
-  Original: 32bit-pkeys.xml */
+  Original: pkeys.xml */
 
 #include "gdbsupport/tdesc.h"
 
 static int
-create_feature_i386_32bit_pkeys (struct target_desc *result, long regnum)
+create_feature_i386_pkeys (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;