From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Keith Seitz <keiths@redhat.com>
Date: Thu, 11 Apr 2024 14:05:42 -0700
Subject: gdb-rhel-10464-xsave-update-2of21.patch

;; Backport "gdb: Store an x86_xsave_layout in i386_gdbarch_tdep."
;; (John Baldwin, RHEL-10464)

This structure is fetched from the current target in i386_gdbarch_init
via a new "fetch_x86_xsave_layout" target method.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -8456,10 +8456,20 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   int bnd0_regnum;
   int num_bnd_cooked;
 
+  x86_xsave_layout xsave_layout = target_fetch_x86_xsave_layout ();
+
   /* If there is already a candidate, use it.  */
-  arches = gdbarch_list_lookup_by_info (arches, &info);
-  if (arches != NULL)
-    return arches->gdbarch;
+  for (arches = gdbarch_list_lookup_by_info (arches, &info);
+       arches != NULL;
+       arches = gdbarch_list_lookup_by_info (arches->next, &info))
+    {
+      /* Check that the XSAVE layout of ARCHES matches the layout for
+	 the current target.  */
+      struct gdbarch_tdep *other_tdep = gdbarch_tdep (arches->gdbarch);
+
+      if (other_tdep->xsave_layout == xsave_layout)
+	return arches->gdbarch;
+    }
 
   /* Allocate space for the new architecture.  Assume i386 for now.  */
   tdep = XCNEW (struct gdbarch_tdep);
@@ -8711,6 +8721,7 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
       gdbarch_free (gdbarch);
       return NULL;
     }
+  tdep->xsave_layout = xsave_layout;
 
   num_bnd_cooked = (tdep->bnd0r_regnum > 0 ? I387_NUM_BND_REGS : 0);
 
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -22,6 +22,7 @@
 
 #include "gdbarch.h"
 #include "infrun.h"
+#include "gdbsupport/x86-xstate.h"
 
 struct frame_info;
 struct gdbarch;
@@ -144,6 +145,9 @@ struct gdbarch_tdep
   /* Offset of XCR0 in XSAVE extended state.  */
   int xsave_xcr0_offset;
 
+  /* Layout of the XSAVE area extended region.  */
+  x86_xsave_layout xsave_layout;
+
   /* Register names.  */
   const char **register_names;
 
diff --git a/gdb/target-debug.h b/gdb/target-debug.h
--- a/gdb/target-debug.h
+++ b/gdb/target-debug.h
@@ -226,4 +226,23 @@ target_debug_print_signals (gdb::array_view<const unsigned char> sigs)
   fputs_unfiltered (" }", gdb_stdlog);
 }
 
+static void
+target_debug_print_x86_xsave_layout (const x86_xsave_layout &layout)
+{
+  fputs_unfiltered ("{", gdb_stdlog);
+  fprintf_unfiltered (gdb_stdlog, " sizeof_xsave=%d", layout.sizeof_xsave);
+#define POFFS(region)							\
+  if (layout.region##_offset != 0)					\
+    fprintf_unfiltered (gdb_stdlog, ", %s_offset=%d", #region,		\
+			layout.region##_offset)
+  POFFS(avx);
+  POFFS(bndregs);
+  POFFS(bndcfg);
+  POFFS(k);
+  POFFS(zmm_h);
+  POFFS(zmm);
+  POFFS(pkru);
+#undef POFFS
+  fputs_unfiltered (" }", gdb_stdlog);
+}
 #endif /* TARGET_DEBUG_H */
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -173,6 +173,7 @@ struct dummy_target : public target_ops
   const struct frame_unwind *get_tailcall_unwinder () override;
   void prepare_to_generate_core () override;
   void done_generating_core () override;
+  x86_xsave_layout fetch_x86_xsave_layout () override;
 };
 
 struct debug_target : public target_ops
@@ -344,6 +345,7 @@ struct debug_target : public target_ops
   const struct frame_unwind *get_tailcall_unwinder () override;
   void prepare_to_generate_core () override;
   void done_generating_core () override;
+  x86_xsave_layout fetch_x86_xsave_layout () override;
 };
 
 void
@@ -4413,3 +4415,27 @@ debug_target::done_generating_core ()
   fputs_unfiltered (")\n", gdb_stdlog);
 }
 
+x86_xsave_layout
+target_ops::fetch_x86_xsave_layout ()
+{
+  return this->beneath ()->fetch_x86_xsave_layout ();
+}
+
+x86_xsave_layout
+dummy_target::fetch_x86_xsave_layout ()
+{
+  return x86_xsave_layout ();
+}
+
+x86_xsave_layout
+debug_target::fetch_x86_xsave_layout ()
+{
+  x86_xsave_layout result;
+  fprintf_unfiltered (gdb_stdlog, "-> %s->fetch_x86_xsave_layout (...)\n", this->beneath ()->shortname ());
+  result = this->beneath ()->fetch_x86_xsave_layout ();
+  fprintf_unfiltered (gdb_stdlog, "<- %s->fetch_x86_xsave_layout (", this->beneath ()->shortname ());
+  fputs_unfiltered (") = ", gdb_stdlog);
+  target_debug_print_x86_xsave_layout (result);
+  fputs_unfiltered ("\n", gdb_stdlog);
+  return result;
+}
diff --git a/gdb/target.c b/gdb/target.c
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -227,6 +227,12 @@ target_has_execution_current (void)
   return target_has_execution_1 (current_inferior ());
 }
 
+x86_xsave_layout
+target_fetch_x86_xsave_layout ()
+{
+  return current_inferior ()->top_target ()->fetch_x86_xsave_layout ();
+}
+
 /* This is used to implement the various target commands.  */
 
 static void
diff --git a/gdb/target.h b/gdb/target.h
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -81,6 +81,7 @@ struct inferior;
 #include "command.h"
 #include "disasm.h"
 #include "tracepoint.h"
+#include "gdbsupport/x86-xstate.h"
 
 #include "gdbsupport/break-common.h" /* For enum target_hw_bp_type.  */
 
@@ -1260,6 +1261,10 @@ struct target_ops
     /* Cleanup after generating a core file.  */
     virtual void done_generating_core ()
       TARGET_DEFAULT_IGNORE ();
+
+    /* Return the x86 XSAVE extended state area layout.  */
+    virtual x86_xsave_layout fetch_x86_xsave_layout ()
+      TARGET_DEFAULT_RETURN (x86_xsave_layout ());
   };
 
 /* Deleter for std::unique_ptr.  See comments in
@@ -2326,6 +2331,8 @@ extern gdb::unique_xmalloc_ptr<char> target_fileio_read_stralloc
 #define target_augmented_libraries_svr4_read() \
   (current_top_target ()->augmented_libraries_svr4_read) ()
 
+extern x86_xsave_layout target_fetch_x86_xsave_layout ();
+
 /* Command logging facility.  */
 
 #define target_log_command(p)					\