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

[Andrew Burgess <aburgess@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=9480801c1f446952d6b499f5fb45e3474ac87a90

commit 9480801c1f446952d6b499f5fb45e3474ac87a90
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Tue Mar 26 18:53:17 2024 +0000

    Revert "gdb/x86: move reading of cs and ds state into gdb/nat directory"
    
    This reverts commit 01ed1674d4435aa4e194fd9373b7705e425ef354.

Diff:
---
 gdb/nat/x86-linux.c | 47 -----------------------------------------------
 gdb/nat/x86-linux.h | 28 ----------------------------
 gdb/x86-linux-nat.c | 42 +++++++++++++++++++++++++++++++++++++-----
 3 files changed, 37 insertions(+), 80 deletions(-)

diff --git a/gdb/nat/x86-linux.c b/gdb/nat/x86-linux.c
index 4242a1baafb..e61f4d749ba 100644
--- a/gdb/nat/x86-linux.c
+++ b/gdb/nat/x86-linux.c
@@ -20,8 +20,6 @@
 #include "gdbsupport/common-defs.h"
 #include "x86-linux.h"
 #include "x86-linux-dregs.h"
-#include "nat/gdb_ptrace.h"
-#include <sys/user.h>
 
 /* Per-thread arch-specific data we want to keep.  */
 
@@ -82,48 +80,3 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp)
 {
   x86_linux_update_debug_registers (lwp);
 }
-
-#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
-
-/* See nat/x86-linux.h.  */
-
-x86_linux_arch_size
-x86_linux_ptrace_get_arch_size (int tid)
-{
-#ifdef __x86_64__
-  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"));
-
-  bool 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"));
-
-  bool is_x32 = ds == AMD64_LINUX_X32_DS;
-
-  return x86_linux_arch_size (is_64bit, is_x32);
-#else
-  return x86_linux_arch_size (false, false);
-#endif
-}
diff --git a/gdb/nat/x86-linux.h b/gdb/nat/x86-linux.h
index 15153ea277e..822882173f9 100644
--- a/gdb/nat/x86-linux.h
+++ b/gdb/nat/x86-linux.h
@@ -47,32 +47,4 @@ extern void x86_linux_delete_thread (struct arch_lwp_info *arch_lwp);
 
 extern void x86_linux_prepare_to_resume (struct lwp_info *lwp);
 
-/* Return value from x86_linux_ptrace_get_arch_size function.  Indicates if
-   a thread is 32-bit, 64-bit, or x32.  */
-
-struct x86_linux_arch_size
-{
-  explicit x86_linux_arch_size (bool is_64bit, bool is_x32)
-    : m_is_64bit (is_64bit),
-      m_is_x32 (is_x32)
-  {
-    /* Nothing.  */
-  }
-
-  bool is_64bit () const
-  { return m_is_64bit; }
-
-  bool is_x32 () const
-  { return m_is_x32; }
-
-private:
-  bool m_is_64bit = false;
-  bool m_is_x32 = false;
-};
-
-/* Use ptrace calls to figure out if thread TID is 32-bit, 64-bit, or
-   64-bit running in x32 mode.  */
-
-extern x86_linux_arch_size x86_linux_ptrace_get_arch_size (int tid);
-
 #endif /* NAT_X86_LINUX_H */
diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c
index b39d05c401f..b93ffca38db 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)
     {