Revert "gdb/x86: move reading of cs and ds state into gdb/nat directory"

This reverts commit 01ed1674d4435aa4e194fd9373b7705e425ef354.

1 files changed, 37 insertions, 5 deletions

diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c
index b39d05c..b93ffca 100644
--- a/gdb/x86-linux-nat.c
+++ b/gdb/x86-linux-nat.c
@@ -91,6 +91,18 @@ x86_linux_nat_target::post_startup_inferior (ptid_t ptid)
   linux_nat_target::post_startup_inferior (ptid);
 }
 
+#ifdef __x86_64__
+/* Value of CS segment register:
+     64bit process: 0x33
+     32bit process: 0x23  */
+#define AMD64_LINUX_USER64_CS 0x33
+
+/* Value of DS segment register:
+     LP64 process: 0x0
+     X32 process: 0x2b  */
+#define AMD64_LINUX_X32_DS 0x2b
+#endif
+
 /* Get Linux/x86 target description from running target.  */
 
 const struct target_desc *
@@ -110,11 +122,31 @@ x86_linux_nat_target::read_description ()
   tid = inferior_ptid.pid ();
 
 #ifdef __x86_64__
-
-  x86_linux_arch_size arch_size = x86_linux_ptrace_get_arch_size (tid);
-  is_64bit = arch_size.is_64bit ();
-  is_x32 = arch_size.is_x32 ();
-
+  {
+    unsigned long cs;
+    unsigned long ds;
+
+    /* Get CS register.  */
+    errno = 0;
+    cs = ptrace (PTRACE_PEEKUSER, tid,
+		 offsetof (struct user_regs_struct, cs), 0);
+    if (errno != 0)
+      perror_with_name (_("Couldn't get CS register"));
+
+    is_64bit = cs == AMD64_LINUX_USER64_CS;
+
+    /* Get DS register.  */
+    errno = 0;
+    ds = ptrace (PTRACE_PEEKUSER, tid,
+		 offsetof (struct user_regs_struct, ds), 0);
+    if (errno != 0)
+      perror_with_name (_("Couldn't get DS register"));
+
+    is_x32 = ds == AMD64_LINUX_X32_DS;
+
+    if (sizeof (void *) == 4 && is_64bit && !is_x32)
+      error (_("Can't debug 64-bit process with 32-bit GDB"));
+  }
 #elif HAVE_PTRACE_GETFPXREGS
   if (have_ptrace_getfpxregs == -1)
     {