From: Markus Metzger <markus.t.metzger@intel.com>
Date: Tue, 26 Nov 2019 11:02:30 +0000 (+0100)
Subject: [wip] gdbserver, x86: support fs_base and gs_base
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=refs%2Fheads%2Fusers%2Fmmetzger%2Ffsgs;p=thirdparty%2Fbinutils-gdb.git

[wip] gdbserver, x86: support fs_base and gs_base

When debugging over gdbserver fs/gs_base is not updated when changing the
corresponding selector.

For 32-bit inferiors, fs/gs_base are now defined but not fetched.

Change-Id: I5a4d8637324ee5f0c303fdcc5eeb8ca50b96c577
Signed-off-by: Markus Metzger  <markus.t.metzger@intel.com>
---

diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 54bd2a26de8..479cec0d709 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -133,7 +133,7 @@ static const int x86_64_regmap[] =
   -1, -1, -1, -1, -1, -1, -1, -1,
   ORIG_RAX * 8,
 #ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
-  21 * 8,  22 * 8,
+  FS_BASE * 8,  GS_BASE * 8,
 #else
   -1, -1,
 #endif
diff --git a/gdb/gdbserver/linux-x86-tdesc.c b/gdb/gdbserver/linux-x86-tdesc.c
index b39ed53549b..ab43ae58c25 100644
--- a/gdb/gdbserver/linux-x86-tdesc.c
+++ b/gdb/gdbserver/linux-x86-tdesc.c
@@ -87,7 +87,13 @@ i386_linux_read_description (uint64_t xcr0)
 
   if (*tdesc == NULL)
     {
-      *tdesc = i386_create_target_description (xcr0, true, false);
+#ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
+      const bool segment = true;
+#else
+      const bool segment = false;
+#endif
+
+      *tdesc = i386_create_target_description (xcr0, true, segment);
 
       init_target_desc (*tdesc, i386_expedite_regs);
     }
@@ -118,7 +124,13 @@ amd64_linux_read_description (uint64_t xcr0, bool is_x32)
 
   if (*tdesc == NULL)
     {
-      *tdesc = amd64_create_target_description (xcr0, is_x32, true, true);
+#ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
+      const bool segment = true;
+#else
+      const bool segment = false;
+#endif
+
+      *tdesc = amd64_create_target_description (xcr0, is_x32, true, segment);
 
       init_target_desc (*tdesc, amd64_expedite_regs);
     }