target/i386: Add GDB XML register description support

This patch implements XML target description support for X86 and X86-64
architectures in the GDB stub, as the way with ARM and PowerPC:
- gdb-xml/32bit-core.xml & gdb-xml/64bit-core.xml: Adding the XML target
  description files, these files are picked from GDB source code.
- configure: Define gdb_xml_files for X86 targets.
- target/i386/cpu.c: Define gdb_core_xml_file and gdb_arch_name to add
  XML awareness for this architecture, modify the gdb_num_core_regs to
  fit the registers number defined in each XML file.

Signed-off-by: Abdallah Bouassida <abdallah.bouassida@lauterbach.com>
Message-Id: <2b3c8119-1602-28c7-eab4-296593877103@lauterbach.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -6023,9 +6023,11 @@ TARGET_ABI_DIR=""
 
 case "$target_name" in
   i386)
+    gdb_xml_files="i386-32bit-core.xml"
   ;;
   x86_64)
     TARGET_BASE_ARCH=i386
+    gdb_xml_files="i386-64bit-core.xml"
   ;;
   alpha)
     mttcg="yes"

gdb-xml/i386-32bit-core.xml

@@ -0,0 +1,65 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2010-2015 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.core">
+  <flags id="i386_eflags" size="4">
+    <field name="CF" start="0" end="0"/>
+    <field name="" start="1" end="1"/>
+    <field name="PF" start="2" end="2"/>
+    <field name="AF" start="4" end="4"/>
+    <field name="ZF" start="6" end="6"/>
+    <field name="SF" start="7" end="7"/>
+    <field name="TF" start="8" end="8"/>
+    <field name="IF" start="9" end="9"/>
+    <field name="DF" start="10" end="10"/>
+    <field name="OF" start="11" end="11"/>
+    <field name="NT" start="14" end="14"/>
+    <field name="RF" start="16" end="16"/>
+    <field name="VM" start="17" end="17"/>
+    <field name="AC" start="18" end="18"/>
+    <field name="VIF" start="19" end="19"/>
+    <field name="VIP" start="20" end="20"/>
+    <field name="ID" start="21" end="21"/>
+  </flags>
+
+  <reg name="eax" bitsize="32" type="int32"/>
+  <reg name="ecx" bitsize="32" type="int32"/>
+  <reg name="edx" bitsize="32" type="int32"/>
+  <reg name="ebx" bitsize="32" type="int32"/>
+  <reg name="esp" bitsize="32" type="data_ptr"/>
+  <reg name="ebp" bitsize="32" type="data_ptr"/>
+  <reg name="esi" bitsize="32" type="int32"/>
+  <reg name="edi" bitsize="32" type="int32"/>
+
+  <reg name="eip" bitsize="32" type="code_ptr"/>
+  <reg name="eflags" bitsize="32" type="i386_eflags"/>
+  <reg name="cs" bitsize="32" type="int32"/>
+  <reg name="ss" bitsize="32" type="int32"/>
+  <reg name="ds" bitsize="32" type="int32"/>
+  <reg name="es" bitsize="32" type="int32"/>
+  <reg name="fs" bitsize="32" type="int32"/>
+  <reg name="gs" bitsize="32" type="int32"/>
+
+  <reg name="st0" bitsize="80" type="i387_ext"/>
+  <reg name="st1" bitsize="80" type="i387_ext"/>
+  <reg name="st2" bitsize="80" type="i387_ext"/>
+  <reg name="st3" bitsize="80" type="i387_ext"/>
+  <reg name="st4" bitsize="80" type="i387_ext"/>
+  <reg name="st5" bitsize="80" type="i387_ext"/>
+  <reg name="st6" bitsize="80" type="i387_ext"/>
+  <reg name="st7" bitsize="80" type="i387_ext"/>
+
+  <reg name="fctrl" bitsize="32" type="int" group="float"/>
+  <reg name="fstat" bitsize="32" type="int" group="float"/>
+  <reg name="ftag" bitsize="32" type="int" group="float"/>
+  <reg name="fiseg" bitsize="32" type="int" group="float"/>
+  <reg name="fioff" bitsize="32" type="int" group="float"/>
+  <reg name="foseg" bitsize="32" type="int" group="float"/>
+  <reg name="fooff" bitsize="32" type="int" group="float"/>
+  <reg name="fop" bitsize="32" type="int" group="float"/>
+</feature>

gdb-xml/i386-64bit-core.xml

@@ -0,0 +1,73 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2010-2015 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.core">
+  <flags id="i386_eflags" size="4">
+    <field name="CF" start="0" end="0"/>
+    <field name="" start="1" end="1"/>
+    <field name="PF" start="2" end="2"/>
+    <field name="AF" start="4" end="4"/>
+    <field name="ZF" start="6" end="6"/>
+    <field name="SF" start="7" end="7"/>
+    <field name="TF" start="8" end="8"/>
+    <field name="IF" start="9" end="9"/>
+    <field name="DF" start="10" end="10"/>
+    <field name="OF" start="11" end="11"/>
+    <field name="NT" start="14" end="14"/>
+    <field name="RF" start="16" end="16"/>
+    <field name="VM" start="17" end="17"/>
+    <field name="AC" start="18" end="18"/>
+    <field name="VIF" start="19" end="19"/>
+    <field name="VIP" start="20" end="20"/>
+    <field name="ID" start="21" end="21"/>
+  </flags>
+
+  <reg name="rax" bitsize="64" type="int64"/>
+  <reg name="rbx" bitsize="64" type="int64"/>
+  <reg name="rcx" bitsize="64" type="int64"/>
+  <reg name="rdx" bitsize="64" type="int64"/>
+  <reg name="rsi" bitsize="64" type="int64"/>
+  <reg name="rdi" bitsize="64" type="int64"/>
+  <reg name="rbp" bitsize="64" type="data_ptr"/>
+  <reg name="rsp" bitsize="64" type="data_ptr"/>
+  <reg name="r8" bitsize="64" type="int64"/>
+  <reg name="r9" bitsize="64" type="int64"/>
+  <reg name="r10" bitsize="64" type="int64"/>
+  <reg name="r11" bitsize="64" type="int64"/>
+  <reg name="r12" bitsize="64" type="int64"/>
+  <reg name="r13" bitsize="64" type="int64"/>
+  <reg name="r14" bitsize="64" type="int64"/>
+  <reg name="r15" bitsize="64" type="int64"/>
+
+  <reg name="rip" bitsize="64" type="code_ptr"/>
+  <reg name="eflags" bitsize="32" type="i386_eflags"/>
+  <reg name="cs" bitsize="32" type="int32"/>
+  <reg name="ss" bitsize="32" type="int32"/>
+  <reg name="ds" bitsize="32" type="int32"/>
+  <reg name="es" bitsize="32" type="int32"/>
+  <reg name="fs" bitsize="32" type="int32"/>
+  <reg name="gs" bitsize="32" type="int32"/>
+
+  <reg name="st0" bitsize="80" type="i387_ext"/>
+  <reg name="st1" bitsize="80" type="i387_ext"/>
+  <reg name="st2" bitsize="80" type="i387_ext"/>
+  <reg name="st3" bitsize="80" type="i387_ext"/>
+  <reg name="st4" bitsize="80" type="i387_ext"/>
+  <reg name="st5" bitsize="80" type="i387_ext"/>
+  <reg name="st6" bitsize="80" type="i387_ext"/>
+  <reg name="st7" bitsize="80" type="i387_ext"/>
+
+  <reg name="fctrl" bitsize="32" type="int" group="float"/>
+  <reg name="fstat" bitsize="32" type="int" group="float"/>
+  <reg name="ftag" bitsize="32" type="int" group="float"/>
+  <reg name="fiseg" bitsize="32" type="int" group="float"/>
+  <reg name="fioff" bitsize="32" type="int" group="float"/>
+  <reg name="foseg" bitsize="32" type="int" group="float"/>
+  <reg name="fooff" bitsize="32" type="int" group="float"/>
+  <reg name="fop" bitsize="32" type="int" group="float"/>
+</feature>

target/i386/cpu.c

@@ -2577,6 +2577,15 @@ out:
     return ret;
 }
 
+static gchar *x86_gdb_arch_name(CPUState *cs)
+{
+#ifdef TARGET_X86_64
+    return g_strdup("i386:x86-64");
+#else
+    return g_strdup("i386");
+#endif
+}
+
 X86CPU *cpu_x86_init(const char *cpu_model)
 {
     return X86_CPU(cpu_generic_init(TYPE_X86_CPU, cpu_model));
@@ -4056,10 +4065,14 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
     cc->write_elf32_qemunote = x86_cpu_write_elf32_qemunote;
     cc->vmsd = &vmstate_x86_cpu;
 #endif
-    /* CPU_NB_REGS * 2 = general regs + xmm regs
-     * 25 = eip, eflags, 6 seg regs, st[0-7], fctrl,...,fop, mxcsr.
-     */
-    cc->gdb_num_core_regs = CPU_NB_REGS * 2 + 25;
+    cc->gdb_arch_name = x86_gdb_arch_name;
+#ifdef TARGET_X86_64
+    cc->gdb_core_xml_file = "i386-64bit-core.xml";
+    cc->gdb_num_core_regs = 40;
+#else
+    cc->gdb_core_xml_file = "i386-32bit-core.xml";
+    cc->gdb_num_core_regs = 32;
+#endif
 #ifndef CONFIG_USER_ONLY
     cc->debug_excp_handler = breakpoint_handler;
 #endif