Add support for Intel PKRU register to GDB and GDBserver.

This patch adds support for the registers added by the
Memory Protection Keys for Userspace (PKU aka PKEYs) feature.
Native and remote debugging are covered by this patch.

The XSAVE area is extended with a new state containing
the 32-bit wide PKRU register. The new register is added to
amd64-avx-mpx_avx512-* tdesc, thus it is renamed accordingly. Also,
respective xstate mask X86_XSTATE_AVX_MPX_AVX512_MASK is renamed to
X86_XSTATE_AVX_MPX_AVX512_PKU_MASK to reflect the new feature set
it supports.

For more information, please refer to the
Intel(R) 64 and IA-32 Architectures Software Developer's
Manual - Septemper 2015
http://www.intel.com/content/dam/www/public/us/en/documents/
manuals/64-ia-32-architectures-software-developer-manual-325462.pdf

gdb/Changelog:
2015-12-08  Michael Sturm  <michael.sturm@intel.com>

     * NEWS: Mention addition of PKU feature.
     * amd64-linux-nat.c (amd64_linux_gregset32_reg_offset): Add PKRU register.
     * amd64-linux-tdep.c (features/i386/amd64-avx-mpx-avx512-linux.c): Rename
       to...
     (features/i386/amd64-avx-mpx-avx512-pku-linux.c): ...this.
     (amd64_linux_gregset_reg_offset): Add PKRU register.
     (amd64_linux_core_read_description): Rename
     X86_XSTATE_AVX_MPX_AVX512_MASK,
     rename tdesc_amd64_avx_mpx_avx512_pku_linux.
     (_initialize_amd64_linux_tdep): Rename
     initialize_tdesc_amd64_avx_mpx_avx512_linux.
     * amd64-linux-tdep.h (AMD64_LINUX_ORIG_RAX_REGNUM): Adjust regnum
     calculation.
     (tdesc_amd64_avx_mpx_avx512_linux): Rename to...
     (tdesc_amd64_avx_mpx_avx512_pku_linux): ...this.
     * amd64-tdep.c (features/i386/amd64-avx-mpx-avx512-pku.c): Rename to...
     (features/i386/amd64-avx-mpx-avx512-pku.c): ...this.
     (amd64_pkeys_names): New register name for raw register PKRU.
     (amd64_init_abi): Add code to initialize PKRU tdep variables if feature
     is present.
     (amd64_target_description): Rename X86_XSTATE_AVX_MPX_AVX512_MASK,
     rename tdesc_amd64_avx_mpx_avx512.
     (_initialize_amd64_tdep): Rename initialize_tdesc_amd64_avx_mpx_avx512.
     * amd64-tdep.h (enum amd64_regnum): Add PKRU register.
     (AMD64_NUM_REGS): Adjust regnum calculation.
     * i386-linux.nat.c (GETXSTATEREGS_SUPPLIES): Extend range of
     registers supplied via XSTATE by PKRU register.
     * common/x86-xstate.h (X86_XSTATE_PKRU): New macro.
     (X86_XSTATE_AVX_MPX_AVX512_MASK): Add PKRU and renamed mask.
     (X86_XSTATE_ALL_MASK): Rename X86_XSTATE_AVX_MPX_AVX512_MASK.
     (X86_XSTATE_PKRU_SIZE): New macro.
     (X86_XSTATE_MAX_SIZE): Adjust size.
     (HAS_PKRU(XCR0)): New macro.
     (X86_XSTATE_SIZE): Add checkfor PKRU.
     * features/Makefile (WHICH): Rename i386/i386-avx-mpx-avx512,
     i386/i386-avx-mpx-avx512-linux, i386/amd64-avx-mpx-avx512,
     i386/amd64-avx-mpx-avx512-linux.
     (i386/i386-avx-mpx-avx512-expedite): Rename expedite.
     (i386/i386-avx-mpx-avx512-linux-expedite): Likewise.
     (i386/amd64-avx-mpx-avx512-expedite): Likewise.
     (i386/amd64-avx-mpx-avx512-linux-expedite): Likewise.
     (XMLTOC): Rename i386/amd64-avx-mpx-avx512-linux.xml,
     i386/amd64-avx-mpx-avx512.xml, i386/i386-avx-mpx-avx512-linux.xml,
     i386/i386-avx-mpx-avx512.xml.
     ((outdir)/i386/i386-avx-mpx-avx512.dat): Rename rule, add
     i386/32bit-pkeys.xml.
     ((outdir)/i386/i386-avx-mpx-avx512-pku-linux.dat): Likewise.
     ((outdir)/i386/amd64-avx-mpx-avx512.dat): Rename rule, add
     i386/64bit-pkeys.xml.
     ((outdir)/i386/amd64-avx-mpx-avx512-linux.dat): Likewise.
     * features/i386/32bit-pkeys.xml: New file.
     * features/i386/64bit-pkeys.xml: Likewise.
     * features/i386/amd64-avx-mpx-avx512-linux-pku.c: Regenerate from
     renamed XML file.
     * features/i386/amd64-avx-mpx-avx512-linux.xml: Rename to
     amd64-avx-mpx-avx512-pku-linux.xml, add 64bit-pkeys.xml
     * features/i386/amd64-avx-mpx-avx512.c: Regenerate from
     renamed XML file.
     * features/i386/amd64-avx-mpx-avx512.xml: Rename to
     amd64-avx-mpx-avx512-pku.xml, add 64bit-pkeys.xml.
     * features/i386/i386-avx-mpx-avx512-linux.c: Regenerate from
     renamed XML file.
     * features/i386/i386-avx-mpx-avx512-linux.xml: Rename to
     i386-avx-mpx-avx512-pku-linux.xml, add 32bit-pkeys.xml.
     * features/i386/i386-avx-mpx-avx512.c: Regenerate from
     renamed XML file.
     * features/i386/i386-avx-mpx-avx512.xml: Rename to
     i386-avx-mpx-avx512-pku.xml, add 32bit-pkeys.xml.
     * i386-linux-nat.c (GETXSTATEREGS_SUPPLIES): Change to use
     I386_PKEYS_NUM_REGS.
     * i386-linux-tdep.c (features/i386/i386-avx-mpx-avx512-linux.c): Rename
     include.
     (i386_linux_gregset_reg_offset): Add PKRU register.
     (i386_linux_core_read_description): Rename xstate mask and returned
     tdesc for X86_XSTATE_AVX_MPX_AVX512_PKU_MASK.
     (_initialize_i386_linux_tdep): Rename
     initialize_tdesc_i386_avx_mpx_avx512_linux.
     * i386-linux-tdep.h (I386_LINUX_ORIG_EAX_REGNUM): Adjuste regnum
     calculation.
     (tdesc_i386_avx_mpx_avx512_linux): Rename prototype.
     (/* Format of XSAVE...): Add pkru register.
     * i386-tdep.c (i386-avx-mpx-avx512.c): Rename include.
     (i386_pkeys_names): New register name for raw register PKRU.
     (i386_pkru_regnum_p): Add function to look up register number of
     PKRU raw register.
     (i386_register_reggroup_p): Add code to exclude PKRU from general
     register group.
     (i386_validate_tdesc_p): Add code to handle PKRU feature, add PKRU
     registers if feature is present in xcr0.
     (i386_gdbarch_init): Adjust number of registers in architecture. Add code
     to initialize PKRU feature variables in tdep structure.
     (i386_target_description): Rename xstate mask and returned
     tdesc for X86_XSTATE_AVX_MPX_AVX512_PKU_MASK.
     (_initialize_i386_tdep): Rename initialize_tdesc_i386_avx_mpx_avx512.
     * i386-tdep.h (struct gdbarch_tdep): Add feature variables to tdep
     structure.
     (enum i386_regnum): Add PKRU register.
     (I386_PKEYS_NUM_REGS): New define for number of registers in PKRU feature.
     (i386_pkru_regnum_p): New prototype.
     * i387-tdep.c (xsave_pkeys_offset): New table for PKRU offsets in
     XSAVE buffer.
     (XSAVE_PKEYS_ADDR): New macro.
     (i387_supply_xsave): Add code to handle PKRU register.
     (i387_collect_xsave): Likewise.
     * i387-tdep.h (I387_NUM_PKEYS_REGS): New define for number of registers
     in PKRU feature.
     (I387_PKRU_REGNUM): New macro.
     (I387_PKEYSEND_REGNUM): Likewise.
     * regformats/i386/amd64_avx_mpx_avx512_pku_linux.dat: Regenerate from
     renamed XML file.
     * regformats/i386/amd64_avx_mpx_avx512_pku.dat: Likewise.
     * regformats/i386/i386/amd64-avx-mpx-avx512-pku.dat: Likewise.
     * regformats/i386/i386_avx_mpx_avx512_pku_linux.dat: Likewise.

testsuite/Changelog:
2016-04-18  Michael Sturm  <michael.sturm@intel.com>

     * gdb.arch/i386-pkru.c: New file.
     * gdb.arch/i386-pkru.exp: Likewise.

gdbserver/Changelog:
2016-04-18  Michael Sturm  <michael.sturm@intel.com>

     * Makefile.in (clean): Rename i386-avx-mpx-avx512.c,
     i386-avx-mpx-avx512-linux.c, amd64-avx-mpx-avx512.c,
     amd64-avx-mpx-avx512-linux.c.
     (i386-avx-mpx-avx512-linux-ipa.o:): Rename rule and source file.
     (amd64-avx-mpx-avx512-linux-ipa.o:): Likewise.
     (i386-avx-mpx-avx512.c :): Rename rule, source files and dat files.
     (i386-avx-mpx-avx512-linux.c :): Likewise.
     (amd64-avx-mpx-avx512.c :): Likewise.
     (amd64-avx-mpx-avx512-linux.c :): Likewise.
     * configure.srv (srv_i386_regobj): Rename i386-avx-mpx-avx512.o.
     (srv_i386_linux_regobj): Rename i386-avx-mpx-avx512-linux.o.
     (srv_amd64_regobj): Rename amd64-avx-mpx-avx512.o.
     (srv_amd64_linux_regobj): Rename amd64-avx-mpx-avx512-linux.o.
     (ipa_i386_linux_regobj): Rename i386-avx-mpx-avx512-linux-ipa.o.
     (ipa_amd64_linux_regobj): Rename amd64-avx-mpx-avx512-pku-linux-ipa.o.
     (srv_i386_32bit_xmlfiles): Add 32bit-pkeys.xml.
     (srv_i386_64bit_xmlfiles): Add 64bit-pkeys.xml.
     (srv_i386_xmlfiles): Rename i386/i386-avx-mpx-avx512.xml.
     (srv_amd64_xmlfiles): Rename i386/amd64-avx-mpx-avx512.xml.
     (srv_i386_linux_xmlfiles): Rename i386/i386-avx-mpx-avx512-linux.xml.
     (srv_amd64_linux_xmlfiles): Rename di386/amd64-avx-mpx-avx512-linux.xml.
     * i387-fp.c (num_pkeys_registers): New variable.
     (struct i387_xsave): Add space for pkru values.
     (i387_cache_to_fsave): Add code to handle PKRU register.
     (i387_xsave_to_cache): Likewise.
     * linux-amd64-ipa.c (get_ipa_tdesc): Rename
     tdesc_amd64_avx_mpx_avx512_linux.
     (initialize_low_tracepoint): Rename
     init_registers_amd64_avx_mpx_avx512_linux.
     * linux-i386-ipa.c (get_ipa_desc): Rename
     tdesc_i386_avx_mpx_avx512_linux.
     (initialize_low_tracepoint): Rename
     init_registers_i386_avx_mpx_avx512_linux.
     * linux-x86-low.c (x86_64_regmap[]): Add PKRU register.
     (x86_linux_read_description): Rename X86_XSTATE_AVX_MPX_AVX512_MASK,
     rename tdesc_amd64_avx_mpx_avx512_linux, rename
     tdesc_i386_avx_mpx_avx512_linux.
     (x86_get_ipa_tdesc_idx): Rename tdesc_amd64_avx_mpx_avx512_linux,
     rename tdesc_i386_avx_mpx_avx512_linux.
     (initialize_low_arch): Rename init_registers_amd64_avx_mpx_avx512_linux,
     rename init_registers_i386_avx_mpx_avx512_linux.
     * linux-x86-tdesc.h (init_registers_amd64_avx_mpx_avx512_linux): Renamed
     prototype.
     (tdesc_amd64_avx_mpx_avx512_linux): Likewise.
     (init_registers_i386_avx_mpx_avx512_linux): Likewise.
     (tdesc_i386_avx_mpx_avx512_linux): Likewise.

doc/Changelog:
2016-04-18  Michael Sturm  <michael.sturm@intel.com>

     * gdb.texinfo (i386 Features): Add description of PKRU register.

Change-Id: If75ce5aba7dfd33fdbe3d8b47f04ef3f550c52be
Signed-off-by: Michael Sturm <michael.sturm@intel.com>

2 files changed, 156 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.arch/i386-pkru.c b/gdb/testsuite/gdb.arch/i386-pkru.c
new file mode 100644
index 0000000..cec78f5
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/i386-pkru.c
@@ -0,0 +1,90 @@
+/* Test program for PKEYS registers.
+
+   Copyright 2015-2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <stddef.h>
+#include "x86-cpuid.h"
+
+#ifndef NOINLINE
+#define NOINLINE __attribute__ ((noinline))
+#endif
+
+unsigned int have_pkru (void) NOINLINE;
+
+static inline unsigned long
+rdpkru (void)
+{
+  unsigned int eax, edx;
+  unsigned int ecx = 0;
+  unsigned int pkru;
+
+  asm volatile (".byte 0x0f,0x01,0xee\n\t"
+               : "=a" (eax), "=d" (edx)
+               : "c" (ecx));
+  pkru = eax;
+  return pkru;
+}
+
+static inline void
+wrpkru (unsigned int pkru)
+{
+  unsigned int eax = pkru;
+  unsigned int ecx = 0;
+  unsigned int edx = 0;
+
+  asm volatile (".byte 0x0f,0x01,0xef\n\t"
+               : : "a" (eax), "c" (ecx), "d" (edx));
+}
+
+unsigned int NOINLINE
+have_pkru (void)
+{
+  unsigned int eax, ebx, ecx, edx;
+
+  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+    return 0;
+
+  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
+    {
+      if (__get_cpuid_max (0, NULL) < 7)
+	return 0;
+
+      __cpuid_count (7, 0, eax, ebx, ecx, edx);
+
+      if ((ecx & bit_PKU) == bit_PKU)
+	return 1;
+    }
+  return 0;
+}
+
+int
+main (int argc, char **argv)
+{
+  unsigned int wr_value = 0x12345678;
+  unsigned int rd_value = 0x0;
+
+  if (have_pkru ())
+    {
+      wrpkru (wr_value);
+      asm ("nop\n\t");	/* break here 1.  */
+
+      rd_value = rdpkru ();
+      asm ("nop\n\t");	/* break here 2.  */
+    }
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/i386-pkru.exp b/gdb/testsuite/gdb.arch/i386-pkru.exp
new file mode 100644
index 0000000..5f243f1
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/i386-pkru.exp
@@ -0,0 +1,66 @@
+# Copyright 2015-2017 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile
+
+if { ![istarget i?86-*-*] && ![istarget x86_64-*-* ] } {
+    unsupported "skipping x86 PKEYS tests."
+    return
+}
+
+set comp_flags "-I${srcdir}/../nat/"
+
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
+     [list debug additional_flags=${comp_flags}]] } {
+    untested "failed to compile x86 PKEYS test.
+    return -1
+}
+
+if ![runto_main] {
+    untested "could not run to main"
+    return -1
+}
+
+set supports_pkru 0
+set test "probe PKRU support"
+gdb_test_multiple "print have_pkru()" $test {
+    -re ".. = 1\r\n$gdb_prompt $" {
+        pass $test
+        set supports_pkru 1
+    }
+}
+
+if { !$supports_pkru } {
+    unsupported "processor does not support protection key feature."
+    return
+}
+
+# Test pkru register at startup
+# set test_string "0"
+
+gdb_test "print \$pkru" "= 0" "pkru register"
+
+# Read values from pseudo registers.
+gdb_breakpoint [ gdb_get_line_number "break here 1" ]
+gdb_continue_to_breakpoint "break here 1" ".*break here 1.*"
+
+gdb_test "info register pkru" ".*pkru.*0x12345678.*" "read pkru register"
+gdb_test "print /x \$pkru = 0x44444444" "= 0x44444444" "set pkru value"
+gdb_test "info register pkru" ".*pkru.*0x44444444.*" "read value after setting value"
+
+gdb_breakpoint [ gdb_get_line_number "break here 2" ]
+gdb_continue_to_breakpoint "break here 2" ".*break here 2.*"
+
+gdb_test "print /x rd_value" "= 0x44444444" "variable after reading pkru"