[PATCH v2] Port GDB to Hurd x86_64.

[PATCH v2] Port GDB to Hurd x86_64.

[Flavio Cruz]

This port extends the existing i686 port to support x86_64 by trying to
reuse existing code whenever it makes sense.

* gdb/amd64-gnu-tdep.c: Adds logic for handling signal frames and
  position of amd64 registers in the different Hurd structs, including
  i386_thread_state. The signal code is very similar to i686, except the
  trampoline code is adapted.
* gdb/amd64-gnu-tdep.h: export register offsets for x86-gnu-nat.c.
* gdb/config/i386/nm-i386gnu.h: renamed to gdb/config/i386/nm-x86-gnu.h
  and adapt it for x86_64.
* gdb/config/i386/i386gnu.mn: renamed to gdb/config/i386/nm-x86-gnu.mn
  and reuse it for x86_64.
* gdb/configure.host: recognize gnu64 as a host.
* gdb/configure.nat: recognize gnu64 host and update existing i386gnu to
  reuse the new shared files.
* gdb/configure.tgt: recognize x86_64-*-gnu* triplet and use
  amd64-gnu-tdep.c.
* gdb/i386-gnu-tdep.c: added i386_gnu_thread_state_reg_offset that is
  copied from i386-gnu-nat.c. This makes it similar to amd64.
* gdb/i386-gnu-tdep.h: export register offsets and number of registers.
* gdb/i386-gnu-nat.c: rename it to x86-gnu-nat.c since we reuse this for
  i386 and amd64. Updated REG_ADDR to use one of the structures. Added
  VALID_REGISTER to make sure it's a register we can provide at this time
  (not all of them are available in amd64). FLAGS_REGISTER is either rfl
  or efl depending on the arch. Renamed functions and class from i386 to x86
  whenever they can be reused.

Tested on Hurd x86_64 and i686.
---

Latest changes:
- Changed svr4_ilp32_fetch_link_map_offsets to
  svr4_lp64_fetch_link_map_offsets in amd64-gnu-tdep.c (duh).
- Added set_gdbarch_* to work better with the glibc and shared
  library features like TLS and PLT in amd64-gnu-tdep.c and also
  i386-gnu-tdep.c

It does seem to work with shared libraries now and I can backtrace inside
library functions from libhurduser up to libc.

 gdb/amd64-gnu-tdep.c                          | 267 ++++++++++++++++++
 gdb/amd64-gnu-tdep.h                          |  29 ++
 .../i386/{nm-i386gnu.h => nm-x86-gnu.h}       |   7 +
 gdb/config/i386/{i386gnu.mn => x86-gnu.mn}    |   0
 gdb/configure.host                            |   1 +
 gdb/configure.nat                             |  27 +-
 gdb/configure.tgt                             |   6 +-
 gdb/i386-gnu-tdep.c                           |  47 ++-
 gdb/i386-gnu-tdep.h                           |  29 ++
 gdb/{i386-gnu-nat.c => x86-gnu-nat.c}         | 128 +++++----
 10 files changed, 479 insertions(+), 62 deletions(-)
 create mode 100644 gdb/amd64-gnu-tdep.c
 create mode 100644 gdb/amd64-gnu-tdep.h
 rename gdb/config/i386/{nm-i386gnu.h => nm-x86-gnu.h} (83%)
 rename gdb/config/i386/{i386gnu.mn => x86-gnu.mn} (100%)
 create mode 100644 gdb/i386-gnu-tdep.h
 rename gdb/{i386-gnu-nat.c => x86-gnu-nat.c} (75%)

diff --git a/gdb/amd64-gnu-tdep.c b/gdb/amd64-gnu-tdep.c
new file mode 100644
index 00000000000..a5e67df5f21
--- /dev/null
+++ b/gdb/amd64-gnu-tdep.c
@@ -0,0 +1,267 @@
+/* Target-dependent code for the GNU Hurd.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "gdbcore.h"
+#include "osabi.h"
+#include "solib-svr4.h"
+
+#include "amd64-tdep.h"
+#include "amd64-gnu-tdep.h"
+#include "glibc-tdep.h"
+
+extern "C"
+{
+#include <mach.h>
+}
+
+/* Recognizing signal handler frames.  */
+
+/* When the GNU/Hurd libc calls a signal handler, the return address points
+   inside the trampoline assembly snippet.
+
+   If the trampoline function name can not be identified, we resort to reading
+   memory from the process in order to identify it.  */
+
+static const gdb_byte gnu_sigtramp_code[] =
+{
+/* rpc_wait_trampoline: */
+  0x48, 0xc7, 0xc0, 0xe7, 0xff, 0xff, 0xff,	/* mov    $-25,%rax */
+  0x0f, 0x05,					/* syscall */
+  0x49, 0x89, 0x04, 0x24,			/* mov    %rax,(%r12) */
+  0x48, 0x89, 0xdc,				/* mov    %rbx,%rsp */
+
+/* trampoline: */
+  0x5f,			                        /* pop    %rdi */
+  0x5e,						/* pop    %rsi */
+  0x5a,						/* pop    %rdx */
+  0x48, 0x83, 0xc4, 0x08,			/* add    $0x8,%rsp */
+  0x41, 0xff, 0xd5,				/* call   *%r13 */
+
+/* RA HERE */
+  0x48, 0x8b, 0x7c, 0x24, 0x10,			/* mov    0x10(%rsp),%rdi */
+  0xc3,						/* ret */
+
+/* firewall: */
+  0xf4,						/* hlt */
+};
+
+#define GNU_SIGTRAMP_LEN (sizeof gnu_sigtramp_code)
+#define GNU_SIGTRAMP_TAIL 7			/* length of tail after RA */
+
+/* If THIS_FRAME is a sigtramp routine, return the address of the
+   start of the routine.  Otherwise, return 0.  */
+
+static CORE_ADDR
+amd64_gnu_sigtramp_start (frame_info_ptr this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  gdb_byte buf[GNU_SIGTRAMP_LEN];
+
+  if (!safe_frame_unwind_memory (this_frame,
+				 pc + GNU_SIGTRAMP_TAIL - GNU_SIGTRAMP_LEN,
+				 buf))
+    return 0;
+
+  if (memcmp (buf, gnu_sigtramp_code, GNU_SIGTRAMP_LEN) != 0)
+    return 0;
+
+  return pc;
+}
+
+/* Return whether THIS_FRAME corresponds to a Hurd sigtramp routine.  */
+
+static int
+amd64_gnu_sigtramp_p (frame_info_ptr this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  const char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+
+  /* If we have a NAME, we can check for the trampoline function */
+  if (name != NULL && strcmp (name, "trampoline") == 0)
+    return 1;
+
+  return amd64_gnu_sigtramp_start (this_frame) != 0;
+}
+
+/* Offset to sc_i386_thread_state in sigcontext, from <bits/sigcontext.h>.  */
+#define AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET 32
+
+/* Assuming THIS_FRAME is a Hurd sigtramp routine, return the
+   address of the associated sigcontext structure.  */
+
+static CORE_ADDR
+amd64_gnu_sigcontext_addr (frame_info_ptr this_frame)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  CORE_ADDR pc;
+  CORE_ADDR sp;
+  gdb_byte buf[8];
+
+  get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
+  sp = extract_unsigned_integer (buf, 8, byte_order);
+
+  pc = amd64_gnu_sigtramp_start (this_frame);
+  if (pc)
+    {
+      CORE_ADDR sigcontext_addr;
+
+      /* The sigcontext structure address is passed as the third argument
+       * of the signal handler but %RDX is not saved across calls. Luckily,
+       * the structured is saved underneath the &__sigreturn and a dummy word
+       * to fill the slot for the address for __sigreturn to return to.
+       */
+      read_memory (sp + 16, buf, 8);
+      sigcontext_addr = extract_unsigned_integer (buf, 8, byte_order);
+      return sigcontext_addr + AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET;
+    }
+
+  error (_("Couldn't recognize signal trampoline."));
+  return 0;
+}
+
+/* Mapping between the general-purpose registers in `struct
+   sigcontext' format (starting at sc_i386_thread_state)
+   and GDB's register cache layout.  */
+
+/* From <bits/sigcontext.h>.  */
+static int amd64_gnu_sc_reg_offset[] =
+{
+  15 * 8,			/* %rax */
+  12 * 8,			/* %rbx */
+  14 * 8,			/* %rcx */
+  13 * 8,			/* %rdx */
+  10 * 8,			/* %rsi */
+  9 * 8,			/* %rdi */
+  10 * 8,			/* %rbp */
+  11 * 8,			/* %rsp */
+  0 * 8,			/* %r8 ...  */
+  8 * 8,
+  7 * 8,
+  6 * 8,
+  3 * 8,
+  2 * 8,
+  1 * 8,
+  0 * 8,			/* ... %r15 */
+  16 * 8,			/* %rip */
+  18 * 8,			/* %eflags */
+  17 * 8,			/* %cs */
+};
+
+/* From <sys/ucontext.h>.  */
+static int amd64_gnu_gregset_reg_offset[] =
+{
+  10 * 8,			/* %rax */
+  5 * 8,			/* %rbx */
+  11 * 8,			/* %rcx */
+  12 * 8,			/* %rdx */
+  13 * 8,			/* %rsi */
+  14 * 8,			/* %rdi */
+  4 * 8,			/* %rbp */
+  19 * 8,			/* %rsp */
+  9 * 8,			/* %r8 ...  */
+  8 * 8,
+  7 * 8,
+  6 * 8,
+  3 * 8,
+  2 * 8,
+  1 * 8,
+  0 * 8,			/* ... %r15 */
+  16 * 8,			/* %rip */
+  18 * 8,			/* %eflags */
+  17 * 8,			/* %cs */
+  -1,				  /* %ss */
+  -1,				  /* %ds */
+  -1,				  /* %es */
+  -1,				  /* %fs */
+  -1,				  /* %gs */
+};
+
+/* Offset to the thread_state_t location where REG is stored.  */
+#define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
+
+/* At REG_OFFSET[N] is the offset to the thread_state_t location where
+   the GDB register N is stored.  */
+int amd64_gnu_thread_state_reg_offset[] =
+{
+  REG_OFFSET (rax),		/* %rax */
+  REG_OFFSET (rbx),		/* %rbx */
+  REG_OFFSET (rcx),		/* %rcx */
+  REG_OFFSET (rdx),		/* %rdx */
+  REG_OFFSET (rsi),		/* %rsi */
+  REG_OFFSET (rdi),		/* %rdi */
+  REG_OFFSET (rbp),		/* %rbp */
+  REG_OFFSET (ursp),	/* %rsp */
+  REG_OFFSET (r8),		/* %r8 ...  */
+  REG_OFFSET (r9),
+  REG_OFFSET (r10),
+  REG_OFFSET (r11),
+  REG_OFFSET (r12),
+  REG_OFFSET (r13),
+  REG_OFFSET (r14),
+  REG_OFFSET (r15),		/* ... %r15 */
+  REG_OFFSET (rip),		/* %rip */
+  REG_OFFSET (rfl),		/* %rflags */
+  REG_OFFSET (cs)	    /* %cs */
+};
+
+const int amd64_gnu_thread_state_num_regs =
+  ARRAY_SIZE (amd64_gnu_thread_state_reg_offset);
+
+static void
+amd64_gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
+
+  amd64_init_abi (info, gdbarch,
+      amd64_target_description (X86_XSTATE_SSE_MASK, true));
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+      svr4_fetch_objfile_link_map);
+
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
+
+  /* Hurd uses the dynamic linker included in the GNU C Library.  */
+  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+  tdep->gregset_reg_offset = amd64_gnu_gregset_reg_offset;
+  tdep->gregset_num_regs = ARRAY_SIZE (amd64_gnu_gregset_reg_offset);
+  tdep->sizeof_gregset = 21 * 8; /* sizeof (struct i386_thread_state); */
+
+  tdep->sigtramp_p = amd64_gnu_sigtramp_p;
+  tdep->sigcontext_addr = amd64_gnu_sigcontext_addr;
+  tdep->sc_reg_offset = amd64_gnu_sc_reg_offset;
+  tdep->sc_num_regs = ARRAY_SIZE (amd64_gnu_sc_reg_offset);
+
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_solib_svr4_fetch_link_map_offsets
+    (gdbarch, svr4_lp64_fetch_link_map_offsets);
+}
+
+void _initialize_amd64_gnu_tdep ();
+void
+_initialize_amd64_gnu_tdep ()
+{
+  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
+			  GDB_OSABI_HURD, amd64_gnu_init_abi);
+}
diff --git a/gdb/amd64-gnu-tdep.h b/gdb/amd64-gnu-tdep.h
new file mode 100644
index 00000000000..70a6e4bfeb6
--- /dev/null
+++ b/gdb/amd64-gnu-tdep.h
@@ -0,0 +1,29 @@
+/* Target-dependent code for Hurd x86-64.
+
+   Copyright (C) 2024 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef AMD64_GNU_TDEP_H
+#define AMD64_GNU_TDEP_H
+
+/* Mapping between the general-purpose registers in Hurd x86_64 thread
+   state and GDB's register cache layout.
+   Indexed by amd64_regnum.  */
+extern int amd64_gnu_thread_state_reg_offset[];
+extern const int amd64_gnu_thread_state_num_regs;
+
+#endif /* AMD64_GNU_TDEP_H */
diff --git a/gdb/config/i386/nm-i386gnu.h b/gdb/config/i386/nm-x86-gnu.h
similarity index 83%
rename from gdb/config/i386/nm-i386gnu.h
rename to gdb/config/i386/nm-x86-gnu.h
index d2d5de83948..ed4d1729227 100644
--- a/gdb/config/i386/nm-i386gnu.h
+++ b/gdb/config/i386/nm-x86-gnu.h
@@ -22,9 +22,16 @@
 /* Thread flavors used in re-setting the T bit.  */
 #define THREAD_STATE_FLAVOR		i386_REGS_SEGS_STATE
 #define THREAD_STATE_SIZE		i386_THREAD_STATE_COUNT
+#ifdef __x86_64__
+#define THREAD_STATE_SET_TRACED(state) \
+	((struct i386_thread_state *) (state))->rfl |= 0x100
+#define THREAD_STATE_CLEAR_TRACED(state) \
+	((((struct i386_thread_state *) (state))->rfl &= ~0x100), 1)
+#else
 #define THREAD_STATE_SET_TRACED(state) \
   	((struct i386_thread_state *) (state))->efl |= 0x100
 #define THREAD_STATE_CLEAR_TRACED(state) \
   	((((struct i386_thread_state *) (state))->efl &= ~0x100), 1)
+#endif /* __x86_64__ */
 
 #endif /* CONFIG_I386_NM_I386GNU_H */
diff --git a/gdb/config/i386/i386gnu.mn b/gdb/config/i386/x86-gnu.mn
similarity index 100%
rename from gdb/config/i386/i386gnu.mn
rename to gdb/config/i386/x86-gnu.mn
diff --git a/gdb/configure.host b/gdb/configure.host
index da71675b201..999af8e59ae 100644
--- a/gdb/configure.host
+++ b/gdb/configure.host
@@ -184,6 +184,7 @@ x86_64-*-mingw*)        gdb_host=mingw64
 			gdb_host_obs=mingw-hdep.o
 			;;
 x86_64-*-cygwin*)	gdb_host=cygwin64 ;;
+x86_64-*-gnu*)		gdb_host=gnu64 ;;
 m32r*-*-linux*)          gdb_host=linux ;;
 
 xtensa*-*-linux*)	gdb_host=linux ;;
diff --git a/gdb/configure.nat b/gdb/configure.nat
index 8b98511cef7..ef404fb791a 100644
--- a/gdb/configure.nat
+++ b/gdb/configure.nat
@@ -211,23 +211,44 @@ case ${gdb_host} in
 		;;
 	esac
 	;;
+    gnu64)
+	case ${gdb_host_cpu} in
+	    i386)
+		# Host: x86_64 running the GNU Hurd
+		NATDEPFILES='x86-gnu-nat.o gnu-nat.o \
+		     x86-nat.o nat/x86-dregs.o nat/x86-xstate.o \
+		     amd64-nat.o fork-child.o \
+		     nat/fork-inferior.o \
+		     notify_S.o process_reply_S.o msg_reply_S.o \
+		     msg_U.o exc_request_U.o exc_request_S.o'
+		HAVE_NATIVE_GCORE_HOST=1
+
+		NAT_FILE='nm-x86-gnu.h'
+		MH_CFLAGS='-D_GNU_SOURCE'
+
+		XM_CLIBS='-lshouldbeinlibc'
+
+		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/x86-gnu.mn"
+		;;
+	esac
+	;;
     i386gnu)
 	case ${gdb_host_cpu} in
 	    i386)
 		# Host: Intel 386 running the GNU Hurd
-		NATDEPFILES='i386-gnu-nat.o gnu-nat.o \
+		NATDEPFILES='x86-gnu-nat.o gnu-nat.o \
 		     x86-nat.o nat/x86-dregs.o fork-child.o \
 		     nat/fork-inferior.o \
 		     notify_S.o process_reply_S.o msg_reply_S.o \
 		     msg_U.o exc_request_U.o exc_request_S.o'
 		HAVE_NATIVE_GCORE_HOST=1
 
-		NAT_FILE='nm-i386gnu.h'
+		NAT_FILE='nm-x86-gnu.h'
 		MH_CFLAGS='-D_GNU_SOURCE'
 
 		XM_CLIBS='-lshouldbeinlibc'
 
-		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/i386gnu.mn"
+		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/x86-gnu.mn"
 		;;
 	esac
 	;;
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 47a674201f9..df9e9917ad1 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -328,7 +328,7 @@ i[34567]86-*-linux*)
 	;;
 i[34567]86-*-gnu*)
 	# Target: Intel 386 running the GNU Hurd
-	gdb_target_obs="i386-gnu-tdep.o solib-svr4.o"
+	gdb_target_obs="i386-gnu-tdep.o glibc-tdep.o solib-svr4.o"
 	;;
 i[34567]86-*-cygwin*)
 	# Target: Intel 386 running win32
@@ -744,6 +744,10 @@ x86_64-*-openbsd*)
 x86_64-*-rtems*)
 	gdb_target_obs="${amd64_tobjs} ${i386_tobjs} i386-bsd-tdep.o"
 	;;
+x86_64-*-gnu*)
+	# Target: x86_64 running the GNU Hurd
+	gdb_target_obs="amd64-gnu-tdep.o glibc-tdep.o solib-svr4.o"
+	;;
 xtensa*-*-*linux*)
 	# Target: GNU/Linux Xtensa
 	gdb_target_obs="xtensa-linux-tdep.o symfile-mem.o linux-tdep.o"
diff --git a/gdb/i386-gnu-tdep.c b/gdb/i386-gnu-tdep.c
index 9ff47147513..d0d9059e883 100644
--- a/gdb/i386-gnu-tdep.c
+++ b/gdb/i386-gnu-tdep.c
@@ -21,7 +21,14 @@
 #include "osabi.h"
 #include "solib-svr4.h"
 
+#include "glibc-tdep.h"
 #include "i386-tdep.h"
+#include "i386-gnu-tdep.h"
+
+extern "C"
+{
+#include <mach.h>
+}
 
 /* Recognizing signal handler frames.  */
 
@@ -72,8 +79,7 @@ i386_gnu_sigtramp_start (frame_info_ptr this_frame)
   return pc;
 }
 
-/* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp
-   routine.  */
+/* Return whether THIS_FRAME corresponds to a Hurd sigtramp routine.  */
 
 static int
 i386_gnu_sigtramp_p (frame_info_ptr this_frame)
@@ -170,6 +176,34 @@ static int i386gnu_gregset_reg_offset[] =
   0 * 4,		/* %gs */
 };
 
+/* Offset to the thread_state_t location where REG is stored.  */
+#define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
+
+/* At REG_OFFSET[N] is the offset to the thread_state_t location where
+   the GDB register N is stored.  */
+int i386_gnu_thread_state_reg_offset[] =
+{
+  REG_OFFSET (eax),	/* %eax */
+  REG_OFFSET (ecx),	/* %ecx */
+  REG_OFFSET (edx),	/* %edx */
+  REG_OFFSET (ebx),	/* %ebx */
+  REG_OFFSET (uesp),	/* %esp */
+  REG_OFFSET (ebp),	/* %ebp */
+  REG_OFFSET (esi),	/* %esi */
+  REG_OFFSET (edi),	/* %edi */
+  REG_OFFSET (eip),	/* %eip */
+  REG_OFFSET (efl),	/* %efl */
+  REG_OFFSET (cs),	/* %cs */
+  REG_OFFSET (ss),	/* %ss */
+  REG_OFFSET (ds),	/* %ds */
+  REG_OFFSET (es),	/* %es */
+  REG_OFFSET (fs),	/* %fs */
+  REG_OFFSET (gs)	/* gs */
+};
+
+const int i386_gnu_thread_state_num_regs =
+  ARRAY_SIZE (i386_gnu_thread_state_reg_offset);
+
 static void
 i386gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
@@ -178,9 +212,18 @@ i386gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   /* GNU uses ELF.  */
   i386_elf_init_abi (info, gdbarch);
 
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
   set_solib_svr4_fetch_link_map_offsets
     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 
+  /* Hurd uses the dynamic linker included in the GNU C Library.  */
+  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+					     svr4_fetch_objfile_link_map);
+
   tdep->gregset_reg_offset = i386gnu_gregset_reg_offset;
   tdep->gregset_num_regs = ARRAY_SIZE (i386gnu_gregset_reg_offset);
   tdep->sizeof_gregset = 19 * 4;
diff --git a/gdb/i386-gnu-tdep.h b/gdb/i386-gnu-tdep.h
new file mode 100644
index 00000000000..32e9a73c667
--- /dev/null
+++ b/gdb/i386-gnu-tdep.h
@@ -0,0 +1,29 @@
+/* Target-dependent code for Hurd i386.
+
+   Copyright (C) 2024 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef I386_GNU_TDEP_H
+#define I386_GNU_TDEP_H
+
+/* Mapping between the general-purpose registers in Hurd i386 thread
+   state and GDB's register cache layout.
+   Indexed by amd64_regnum.  */
+extern int i386_gnu_thread_state_reg_offset[];
+extern const int i386_gnu_thread_state_num_regs;
+
+#endif /* I386_GNU_TDEP_H */
diff --git a/gdb/i386-gnu-nat.c b/gdb/x86-gnu-nat.c
similarity index 75%
rename from gdb/i386-gnu-nat.c
rename to gdb/x86-gnu-nat.c
index 0b0759179aa..9a28c5e6a11 100644
--- a/gdb/i386-gnu-nat.c
+++ b/gdb/x86-gnu-nat.c
@@ -35,29 +35,41 @@ extern "C"
 #include "floatformat.h"
 #include "regcache.h"
 
+#ifdef __x86_64__
+#include "amd64-tdep.h"
+#include "amd64-nat.h"
+#include "amd64-gnu-tdep.h"
+#else
 #include "i386-tdep.h"
+#include "i386-gnu-tdep.h"
+#endif
 
 #include "inf-child.h"
 #include "i387-tdep.h"
 
-/* Offset to the thread_state_t location where REG is stored.  */
-#define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
+#ifdef __x86_64__
 
-/* At REG_OFFSET[N] is the offset to the thread_state_t location where
-   the GDB register N is stored.  */
-static int reg_offset[] =
-{
-  REG_OFFSET (eax), REG_OFFSET (ecx), REG_OFFSET (edx), REG_OFFSET (ebx),
-  REG_OFFSET (uesp), REG_OFFSET (ebp), REG_OFFSET (esi), REG_OFFSET (edi),
-  REG_OFFSET (eip), REG_OFFSET (efl), REG_OFFSET (cs), REG_OFFSET (ss),
-  REG_OFFSET (ds), REG_OFFSET (es), REG_OFFSET (fs), REG_OFFSET (gs)
-};
+#define REG_ADDR(state, regnum) \
+  ((char *)(state) + amd64_gnu_thread_state_reg_offset[regnum])
+#define VALID_REGISTER(regnum) \
+  ((regnum) >= 0 && (regnum) < amd64_gnu_thread_state_num_regs)
+#define NUM_GREGS amd64_gnu_thread_state_num_regs
+#define FLAGS_REGISTER rfl
 
-#define REG_ADDR(state, regnum) ((char *)(state) + reg_offset[regnum])
+#else
+
+#define REG_ADDR(state, regnum) \
+  ((char *)(state) + i386_gnu_thread_state_reg_offset[regnum])
+#define VALID_REGISTER(regnum) \
+  ((regnum) >= 0 && (regnum) < i386_gnu_thread_state_num_regs)
+#define NUM_GREGS i386_gnu_thread_state_num_regs
+#define FLAGS_REGISTER efl
+
+#endif  /* __x86_64__ */
 
 \f
 
-/* The i386 GNU Hurd target.  */
+/* The x86 GNU Hurd target.  */
 
 #ifdef i386_DEBUG_STATE
 using gnu_base_target = x86_nat_target<gnu_nat_target>;
@@ -65,13 +77,13 @@ using gnu_base_target = x86_nat_target<gnu_nat_target>;
 using gnu_base_target = gnu_nat_target;
 #endif
 
-struct i386_gnu_nat_target final : public gnu_base_target
+struct x86_gnu_nat_target final : public gnu_base_target
 {
   void fetch_registers (struct regcache *, int) override;
   void store_registers (struct regcache *, int) override;
 };
 
-static i386_gnu_nat_target the_i386_gnu_nat_target;
+static x86_gnu_nat_target the_x86_gnu_nat_target;
 
 /* Get the whole floating-point state of THREAD and record the values
    of the corresponding (pseudo) registers.  */
@@ -106,7 +118,7 @@ fetch_fpregs (struct regcache *regcache, struct proc *thread)
 
 /* Fetch register REGNO, or all regs if REGNO is -1.  */
 void
-i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
+x86_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 {
   struct proc *thread;
   ptid_t ptid = regcache->ptid ();
@@ -119,7 +131,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
     error (_("Can't fetch registers from thread %s: No such thread"),
 	   target_pid_to_str (ptid).c_str ());
 
-  if (regno < I386_NUM_GREGS || regno == -1)
+  if (VALID_REGISTER (regno) || regno == -1)
     {
       thread_state_t state;
 
@@ -138,7 +150,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 
 	  proc_debug (thread, "fetching all register");
 
-	  for (i = 0; i < I386_NUM_GREGS; i++)
+	  for (i = 0; i < NUM_GREGS; i++)
 	    regcache->raw_supply (i, REG_ADDR (state, i));
 	  thread->fetched_regs = ~0;
 	}
@@ -153,7 +165,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 	}
     }
 
-  if (regno >= I386_NUM_GREGS || regno == -1)
+  if (!VALID_REGISTER(regno) || regno == -1)
     {
       proc_debug (thread, "fetching floating-point registers");
 
@@ -196,7 +208,7 @@ store_fpregs (const struct regcache *regcache, struct proc *thread, int regno)
 
 /* Store at least register REGNO, or all regs if REGNO == -1.  */
 void
-i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
+x86_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 {
   struct proc *thread;
   struct gdbarch *gdbarch = regcache->arch ();
@@ -210,7 +222,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
     error (_("Couldn't store registers into thread %s: No such thread"),
 	   target_pid_to_str (ptid).c_str ());
 
-  if (regno < I386_NUM_GREGS || regno == -1)
+  if (VALID_REGISTER (regno) || regno == -1)
     {
       thread_state_t state;
       thread_state_data_t old_state;
@@ -231,14 +243,14 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 
       /* Save the T bit.  We might try to restore the %eflags register
 	 below, but changing the T bit would seriously confuse GDB.  */
-      trace = ((struct i386_thread_state *)state)->efl & 0x100;
+      trace = ((struct i386_thread_state *)state)->FLAGS_REGISTER & 0x100;
 
       if (!was_aborted && was_valid)
 	/* See which registers have changed after aborting the thread.  */
 	{
 	  int check_regno;
 
-	  for (check_regno = 0; check_regno < I386_NUM_GREGS; check_regno++)
+	  for (check_regno = 0; check_regno < NUM_GREGS; check_regno++)
 	    if ((thread->fetched_regs & (1 << check_regno))
 		&& memcpy (REG_ADDR (&old_state, check_regno),
 			   REG_ADDR (state, check_regno),
@@ -263,7 +275,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 
 	  proc_debug (thread, "storing all registers");
 
-	  for (i = 0; i < I386_NUM_GREGS; i++)
+	  for (i = 0; i < NUM_GREGS; i++)
 	    if (REG_VALID == regcache->get_register_status (i))
 	      regcache->raw_collect (i, REG_ADDR (state, i));
 	}
@@ -277,11 +289,11 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 	}
 
       /* Restore the T bit.  */
-      ((struct i386_thread_state *)state)->efl &= ~0x100;
-      ((struct i386_thread_state *)state)->efl |= trace;
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER &= ~0x100;
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER |= trace;
     }
 
-  if (regno >= I386_NUM_GREGS || regno == -1)
+  if (!VALID_REGISTER (regno) || regno == -1)
     {
       proc_debug (thread, "storing floating-point registers");
 
@@ -296,7 +308,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 /* Get debug registers for thread THREAD.  */
 
 static void
-i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
+x86_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 {
   mach_msg_type_number_t count = i386_DEBUG_STATE_COUNT;
   kern_return_t err;
@@ -311,7 +323,7 @@ i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 /* Set debug registers for thread THREAD.  */
 
 static void
-i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
+x86_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 {
   kern_return_t err;
 
@@ -325,23 +337,23 @@ i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 /* Set DR_CONTROL in THREAD.  */
 
 static void
-i386_gnu_dr_set_control_one (struct proc *thread, void *arg)
+x86_gnu_dr_set_control_one (struct proc *thread, void *arg)
 {
   unsigned long *control = (unsigned long *) arg;
   struct i386_debug_state regs;
 
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
   regs.dr[DR_CONTROL] = *control;
-  i386_gnu_dr_set (&regs, thread);
+  x86_gnu_dr_set (&regs, thread);
 }
 
 /* Set DR_CONTROL to CONTROL in all threads.  */
 
 static void
-i386_gnu_dr_set_control (unsigned long control)
+x86_gnu_dr_set_control (unsigned long control)
 {
   inf_update_procs (gnu_current_inf);
-  inf_threads (gnu_current_inf, i386_gnu_dr_set_control_one, &control);
+  inf_threads (gnu_current_inf, x86_gnu_dr_set_control_one, &control);
 }
 
 /* Parameters to set a debugging address.  */
@@ -355,20 +367,20 @@ struct reg_addr
 /* Set address REGNUM (zero based) to ADDR in THREAD.  */
 
 static void
-i386_gnu_dr_set_addr_one (struct proc *thread, void *arg)
+x86_gnu_dr_set_addr_one (struct proc *thread, void *arg)
 {
   struct reg_addr *reg_addr = (struct reg_addr *) arg;
   struct i386_debug_state regs;
 
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
   regs.dr[reg_addr->regnum] = reg_addr->addr;
-  i386_gnu_dr_set (&regs, thread);
+  x86_gnu_dr_set (&regs, thread);
 }
 
 /* Set address REGNUM (zero based) to ADDR in all threads.  */
 
 static void
-i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
+x86_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
 {
   struct reg_addr reg_addr;
 
@@ -378,13 +390,13 @@ i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
   reg_addr.addr = addr;
 
   inf_update_procs (gnu_current_inf);
-  inf_threads (gnu_current_inf, i386_gnu_dr_set_addr_one, &reg_addr);
+  inf_threads (gnu_current_inf, x86_gnu_dr_set_addr_one, &reg_addr);
 }
 
 /* Get debug register REGNUM value from only the one LWP of PTID.  */
 
 static unsigned long
-i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
+x86_gnu_dr_get_reg (ptid_t ptid, int regnum)
 {
   struct i386_debug_state regs;
   struct proc *thread;
@@ -393,7 +405,7 @@ i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
   inf_update_procs (gnu_current_inf);
 
   thread = inf_tid_to_thread (gnu_current_inf, ptid.lwp ());
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
 
   return regs.dr[regnum];
 }
@@ -401,46 +413,50 @@ i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
 /* Return the inferior's debug register REGNUM.  */
 
 static CORE_ADDR
-i386_gnu_dr_get_addr (int regnum)
+x86_gnu_dr_get_addr (int regnum)
 {
   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 
-  return i386_gnu_dr_get_reg (inferior_ptid, regnum);
+  return x86_gnu_dr_get_reg (inferior_ptid, regnum);
 }
 
 /* Get DR_STATUS from only the one thread of INFERIOR_PTID.  */
 
 static unsigned long
-i386_gnu_dr_get_status (void)
+x86_gnu_dr_get_status (void)
 {
-  return i386_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
 }
 
 /* Return the inferior's DR7 debug control register.  */
 
 static unsigned long
-i386_gnu_dr_get_control (void)
+x86_gnu_dr_get_control (void)
 {
-  return i386_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
 }
 #endif /* i386_DEBUG_STATE */
 
-void _initialize_i386gnu_nat ();
+void _initialize_x86_gnu_nat ();
 void
-_initialize_i386gnu_nat ()
+_initialize_x86_gnu_nat ()
 {
 #ifdef i386_DEBUG_STATE
-  x86_dr_low.set_control = i386_gnu_dr_set_control;
+  x86_dr_low.set_control = x86_gnu_dr_set_control;
   gdb_assert (DR_FIRSTADDR == 0 && DR_LASTADDR < i386_DEBUG_STATE_COUNT);
-  x86_dr_low.set_addr = i386_gnu_dr_set_addr;
-  x86_dr_low.get_addr = i386_gnu_dr_get_addr;
-  x86_dr_low.get_status = i386_gnu_dr_get_status;
-  x86_dr_low.get_control = i386_gnu_dr_get_control;
+  x86_dr_low.set_addr = x86_gnu_dr_set_addr;
+  x86_dr_low.get_addr = x86_gnu_dr_get_addr;
+  x86_dr_low.get_status = x86_gnu_dr_get_status;
+  x86_dr_low.get_control = x86_gnu_dr_get_control;
+#ifdef __x86_64__
+  x86_set_debug_register_length (8);
+#else
   x86_set_debug_register_length (4);
+#endif
 #endif /* i386_DEBUG_STATE */
 
-  gnu_target = &the_i386_gnu_nat_target;
+  gnu_target = &the_x86_gnu_nat_target;
 
   /* Register the target.  */
-  add_inf_child_target (&the_i386_gnu_nat_target);
+  add_inf_child_target (&the_x86_gnu_nat_target);
 }
-- 
2.39.2

Re: [PATCH] Port GDB to Hurd x86_64.

[John Baldwin]

On 2/12/24 8:31 PM, Flavio Cruz wrote:
> This port extends the existing i686 port to support x86_64 by trying to
> reuse existing code whenever it makes sense.
> 
> * gdb/amd64-gnu-tdep.c: Adds logic for handling signal frames and
>    position of amd64 registers in the different Hurd structs, including
>    i386_thread_state. The signal code is very similar to i686, except the
>    trampoline code is adapted.
> * gdb/amd64-gnu-tdep.h: export register offsets for x86-gnu-nat.c.
> * gdb/config/i386/nm-i386gnu.h: renamed to gdb/config/i386/nm-x86-gnu.h
>    and adapt it for x86_64.
> * gdb/config/i386/i386gnu.mn: renamed to gdb/config/i386/nm-x86-gnu.mn
>    and reuse it for x86_64.
> * gdb/configure.host: recognize gnu64 as a host.
> * gdb/configure.nat: recognize gnu64 host and update existing i386gnu to
>    reuse the new shared files.
> * gdb/configure.tgt: recognize x86_64-*-gnu* triplet and use
>    amd64-gnu-tdep.c.
> * gdb/i386-gnu-tdep.c: added i386_gnu_thread_state_reg_offset that is
>    copied from i386-gnu-nat.c. This makes it similar to amd64.
> * gdb/i386-gnu-tdep.h: export register offsets and number of registers.
> * gdb/i386-gnu-nat.c: rename it to x86-gnu-nat.c since we reuse this for
>    i386 and amd64. Updated REG_ADDR to use one of the structures. Added
>    VALID_REGISTER to make sure it's a register we can provide at this time
>    (not all of them are available in amd64). FLAGS_REGISTER is either rfl
>    or efl depending on the arch. Renamed functions and class from i386 to x86
>    whenever they can be reused.
> 
> Tested on Hurd x86_64 and i686.
> ---
> 
> For Hurd x86_64 to work, "[PATCH] Hurd port: update interface to match
> upstream and fix warnings" needs to be applied too.
> 
>   gdb/amd64-gnu-tdep.c                          | 256 ++++++++++++++++++
>   gdb/amd64-gnu-tdep.h                          |  29 ++
>   .../i386/{nm-i386gnu.h => nm-x86-gnu.h}       |   7 +
>   gdb/config/i386/{i386gnu.mn => x86-gnu.mn}    |   0
>   gdb/configure.host                            |   1 +
>   gdb/configure.nat                             |  27 +-
>   gdb/configure.tgt                             |   4 +
>   gdb/i386-gnu-tdep.c                           |  37 ++-
>   gdb/i386-gnu-tdep.h                           |  29 ++
>   gdb/{i386-gnu-nat.c => x86-gnu-nat.c}         | 128 +++++----
>   10 files changed, 457 insertions(+), 61 deletions(-)
>   create mode 100644 gdb/amd64-gnu-tdep.c
>   create mode 100644 gdb/amd64-gnu-tdep.h
>   rename gdb/config/i386/{nm-i386gnu.h => nm-x86-gnu.h} (83%)
>   rename gdb/config/i386/{i386gnu.mn => x86-gnu.mn} (100%)
>   create mode 100644 gdb/i386-gnu-tdep.h
>   rename gdb/{i386-gnu-nat.c => x86-gnu-nat.c} (75%)
> 
> diff --git a/gdb/amd64-gnu-tdep.c b/gdb/amd64-gnu-tdep.c
> new file mode 100644
> index 00000000000..57aeccea8b9
> --- /dev/null
> +++ b/gdb/amd64-gnu-tdep.c
> @@ -0,0 +1,256 @@
> +/* Mapping between the general-purpose registers in `struct
> +   sigcontext' format (starting at sc_i386_thread_state)
> +   and GDB's register cache layout.  */
> +
> +/* From <bits/sigcontext.h>.  */
> +static int amd64_gnu_sc_reg_offset[] =
> +{
> +  15 * 8,			/* %rax */
> +  12 * 8,			/* %rbx */
> +  14 * 8,			/* %rcx */
> +  13 * 8,			/* %rdx */
> +  10 * 8,			/* %rsi */
> +  9 * 8,			/* %rdi */
> +  10 * 8,			/* %rbp */
> +  11 * 8,			/* %rsp */
> +  0 * 8,			/* %r8 ...  */
> +  8 * 8,
> +  7 * 8,
> +  6 * 8,
> +  3 * 8,
> +  2 * 8,
> +  1 * 8,
> +  0 * 8,			/* ... %r15 */
> +  16 * 8,			/* %rip */
> +  18 * 8,			/* %eflags */
> +  17 * 8,			/* %cs */
> +};
> +
> +/* From <sys/ucontext.h>.  */
> +static int amd64_gnu_gregset_reg_offset[] =
> +{
> +  10 * 8,			/* %rax */
> +  5 * 8,			/* %rbx */
> +  11 * 8,			/* %rcx */
> +  12 * 8,			/* %rdx */
> +  13 * 8,			/* %rsi */
> +  14 * 8,			/* %rdi */
> +  4 * 8,			/* %rbp */
> +  19 * 8,			/* %rsp */
> +  9 * 8,			/* %r8 ...  */
> +  8 * 8,
> +  7 * 8,
> +  6 * 8,
> +  3 * 8,
> +  2 * 8,
> +  1 * 8,
> +  0 * 8,			/* ... %r15 */
> +  16 * 8,			/* %rip */
> +  18 * 8,			/* %eflags */
> +  17 * 8,			/* %cs */
> +  -1,				  /* %ss */
> +  -1,				  /* %ds */
> +  -1,				  /* %es */
> +  -1,				  /* %fs */
> +  -1,				  /* %gs */
> +};
> +
> +/* Offset to the thread_state_t location where REG is stored.  */
> +#define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)

You can't use a reference to this OS-specific type in a tdep.c file,
only in a nat.c file.  tdep.c should be buildable on other platforms
to permit cross debugging of core dumps, remote targets, etc.

> +/* At REG_OFFSET[N] is the offset to the thread_state_t location where
> +   the GDB register N is stored.  */
> +int amd64_gnu_thread_state_reg_offset[] =
> +{
> +  REG_OFFSET (rax),		/* %rax */
> +  REG_OFFSET (rbx),		/* %rbx */
> +  REG_OFFSET (rcx),		/* %rcx */
> +  REG_OFFSET (rdx),		/* %rdx */
> +  REG_OFFSET (rsi),		/* %rsi */
> +  REG_OFFSET (rdi),		/* %rdi */
> +  REG_OFFSET (rbp),		/* %rbp */
> +  REG_OFFSET (ursp),	/* %rsp */
> +  REG_OFFSET (r8),		/* %r8 ...  */
> +  REG_OFFSET (r9),
> +  REG_OFFSET (r10),
> +  REG_OFFSET (r11),
> +  REG_OFFSET (r12),
> +  REG_OFFSET (r13),
> +  REG_OFFSET (r14),
> +  REG_OFFSET (r15),		/* ... %r15 */
> +  REG_OFFSET (rip),		/* %rip */
> +  REG_OFFSET (rfl),		/* %rflags */
> +  REG_OFFSET (cs)	    /* %cs */
> +};
> +
> +const int amd64_gnu_thread_state_num_regs =
> +  ARRAY_SIZE (amd64_gnu_thread_state_reg_offset);

That said, I also don't see any references to amd64_gnu_thread_state_*
in this file, and it looks to only be used in x86-gnu-nat.c, so I think
you should instead move this array to x86-gnu-nat.c instead (and
similarly for i386_gnu_thread_state_* you added in i386-gnu-tdep.c).

-- 
John Baldwin

[PATCH v2] Port GDB to Hurd x86_64.

[Flavio Cruz]

This port extends the existing i686 port to support x86_64 by trying to
reuse existing code whenever it makes sense.

* gdb/amd64-gnu-tdep.c: Adds logic for handling signal frames and
  position of amd64 registers in the different Hurd structs.
  The signal code is very similar to i686, except the trampoline code
  is adapted.
* gdb/config/i386/nm-i386gnu.h: renamed to gdb/config/i386/nm-x86-gnu.h
  and adapt it for x86_64.
* gdb/config/i386/i386gnu.mn: renamed to gdb/config/i386/nm-x86-gnu.mn
  and reuse it for x86_64.
* gdb/configure.host: recognize gnu64 as a host.
* gdb/configure.nat: recognize gnu64 host and update existing i386gnu to
  reuse the new shared files.
* gdb/configure.tgt: recognize x86_64-*-gnu* triplet and use
  amd64-gnu-tdep.c.
* gdb/i386-gnu-tdep.c: added i386_gnu_thread_state_reg_offset that is
  copied from i386-gnu-nat.c. This makes it similar to amd64.
* gdb/i386-gnu-nat.c: rename it to x86-gnu-nat.c since we reuse this for
  i386 and amd64. Updated REG_ADDR to use one of the structures. Added
  VALID_REGISTER to make sure it's a register we can provide at this time
  (not all of them are available in amd64). FLAGS_REGISTER is either rfl
  or efl depending on the arch. Renamed functions and class from i386 to x86
  whenever they can be reused.

Tested on Hurd x86_64 and i686.
---

I addressed John's comments and moved amd64_gnu_thread_state_* and
i386_gnu_thread_state_* to x86-gnu-nat.c. The new patch also contains a few
changes that makes backtracing through shared libraries work.


 gdb/amd64-gnu-tdep.c                          | 230 ++++++++++++++++++
 .../i386/{nm-i386gnu.h => nm-x86-gnu.h}       |   7 +
 gdb/config/i386/{i386gnu.mn => x86-gnu.mn}    |   0
 gdb/configure.host                            |   1 +
 gdb/configure.nat                             |  27 +-
 gdb/configure.tgt                             |   6 +-
 gdb/i386-gnu-tdep.c                           |  13 +-
 gdb/{i386-gnu-nat.c => x86-gnu-nat.c}         | 171 +++++++++----
 8 files changed, 399 insertions(+), 56 deletions(-)
 create mode 100644 gdb/amd64-gnu-tdep.c
 rename gdb/config/i386/{nm-i386gnu.h => nm-x86-gnu.h} (83%)
 rename gdb/config/i386/{i386gnu.mn => x86-gnu.mn} (100%)
 rename gdb/{i386-gnu-nat.c => x86-gnu-nat.c} (69%)

diff --git a/gdb/amd64-gnu-tdep.c b/gdb/amd64-gnu-tdep.c
new file mode 100644
index 00000000000..0776ec70dd7
--- /dev/null
+++ b/gdb/amd64-gnu-tdep.c
@@ -0,0 +1,230 @@
+/* Target-dependent code for the GNU Hurd.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "gdbcore.h"
+#include "osabi.h"
+#include "solib-svr4.h"
+
+#include "amd64-tdep.h"
+#include "glibc-tdep.h"
+
+/* Recognizing signal handler frames.  */
+
+/* When the GNU/Hurd libc calls a signal handler, the return address points
+   inside the trampoline assembly snippet.
+
+   If the trampoline function name can not be identified, we resort to reading
+   memory from the process in order to identify it.  */
+
+static const gdb_byte gnu_sigtramp_code[] =
+{
+/* rpc_wait_trampoline: */
+  0x48, 0xc7, 0xc0, 0xe7, 0xff, 0xff, 0xff,	/* mov    $-25,%rax */
+  0x0f, 0x05,					/* syscall */
+  0x49, 0x89, 0x04, 0x24,			/* mov    %rax,(%r12) */
+  0x48, 0x89, 0xdc,				/* mov    %rbx,%rsp */
+
+/* trampoline: */
+  0x5f,			                        /* pop    %rdi */
+  0x5e,						/* pop    %rsi */
+  0x5a,						/* pop    %rdx */
+  0x48, 0x83, 0xc4, 0x08,			/* add    $0x8,%rsp */
+  0x41, 0xff, 0xd5,				/* call   *%r13 */
+
+/* RA HERE */
+  0x48, 0x8b, 0x7c, 0x24, 0x10,			/* mov    0x10(%rsp),%rdi */
+  0xc3,						/* ret */
+
+/* firewall: */
+  0xf4,						/* hlt */
+};
+
+#define GNU_SIGTRAMP_LEN (sizeof gnu_sigtramp_code)
+#define GNU_SIGTRAMP_TAIL 7			/* length of tail after RA */
+
+/* If THIS_FRAME is a sigtramp routine, return the address of the
+   start of the routine.  Otherwise, return 0.  */
+
+static CORE_ADDR
+amd64_gnu_sigtramp_start (frame_info_ptr this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  gdb_byte buf[GNU_SIGTRAMP_LEN];
+
+  if (!safe_frame_unwind_memory (this_frame,
+				 pc + GNU_SIGTRAMP_TAIL - GNU_SIGTRAMP_LEN,
+				 buf))
+    return 0;
+
+  if (memcmp (buf, gnu_sigtramp_code, GNU_SIGTRAMP_LEN) != 0)
+    return 0;
+
+  return pc;
+}
+
+/* Return whether THIS_FRAME corresponds to a Hurd sigtramp routine.  */
+
+static int
+amd64_gnu_sigtramp_p (frame_info_ptr this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  const char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+
+  /* If we have a NAME, we can check for the trampoline function */
+  if (name != NULL && strcmp (name, "trampoline") == 0)
+    return 1;
+
+  return amd64_gnu_sigtramp_start (this_frame) != 0;
+}
+
+/* Offset to sc_i386_thread_state in sigcontext, from <bits/sigcontext.h>.  */
+#define AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET 32
+
+/* Assuming THIS_FRAME is a Hurd sigtramp routine, return the
+   address of the associated sigcontext structure.  */
+
+static CORE_ADDR
+amd64_gnu_sigcontext_addr (frame_info_ptr this_frame)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  CORE_ADDR pc;
+  CORE_ADDR sp;
+  gdb_byte buf[8];
+
+  get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
+  sp = extract_unsigned_integer (buf, 8, byte_order);
+
+  pc = amd64_gnu_sigtramp_start (this_frame);
+  if (pc)
+    {
+      CORE_ADDR sigcontext_addr;
+
+      /* The sigcontext structure address is passed as the third argument
+       * of the signal handler but %RDX is not saved across calls. Luckily,
+       * the structured is saved underneath the &__sigreturn and a dummy word
+       * to fill the slot for the address for __sigreturn to return to.
+       */
+      read_memory (sp + 16, buf, 8);
+      sigcontext_addr = extract_unsigned_integer (buf, 8, byte_order);
+      return sigcontext_addr + AMD64_GNU_SIGCONTEXT_THREAD_STATE_OFFSET;
+    }
+
+  error (_("Couldn't recognize signal trampoline."));
+  return 0;
+}
+
+/* Mapping between the general-purpose registers in `struct
+   sigcontext' format (starting at sc_i386_thread_state)
+   and GDB's register cache layout.  */
+
+/* From <bits/sigcontext.h>.  */
+static int amd64_gnu_sc_reg_offset[] =
+{
+  15 * 8,			/* %rax */
+  12 * 8,			/* %rbx */
+  14 * 8,			/* %rcx */
+  13 * 8,			/* %rdx */
+  10 * 8,			/* %rsi */
+  9 * 8,			/* %rdi */
+  10 * 8,			/* %rbp */
+  11 * 8,			/* %rsp */
+  0 * 8,			/* %r8 ...  */
+  8 * 8,
+  7 * 8,
+  6 * 8,
+  3 * 8,
+  2 * 8,
+  1 * 8,
+  0 * 8,			/* ... %r15 */
+  16 * 8,			/* %rip */
+  18 * 8,			/* %eflags */
+  17 * 8,			/* %cs */
+};
+
+/* From <sys/ucontext.h>.  */
+static int amd64_gnu_gregset_reg_offset[] =
+{
+  10 * 8,			/* %rax */
+  5 * 8,			/* %rbx */
+  11 * 8,			/* %rcx */
+  12 * 8,			/* %rdx */
+  13 * 8,			/* %rsi */
+  14 * 8,			/* %rdi */
+  4 * 8,			/* %rbp */
+  19 * 8,			/* %rsp */
+  9 * 8,			/* %r8 ...  */
+  8 * 8,
+  7 * 8,
+  6 * 8,
+  3 * 8,
+  2 * 8,
+  1 * 8,
+  0 * 8,			/* ... %r15 */
+  16 * 8,			/* %rip */
+  18 * 8,			/* %eflags */
+  17 * 8,			/* %cs */
+  -1,				  /* %ss */
+  -1,				  /* %ds */
+  -1,				  /* %es */
+  -1,				  /* %fs */
+  -1,				  /* %gs */
+};
+
+static void
+amd64_gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
+
+  amd64_init_abi (info, gdbarch,
+      amd64_target_description (X86_XSTATE_SSE_MASK, true));
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+      svr4_fetch_objfile_link_map);
+
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
+
+  /* Hurd uses the dynamic linker included in the GNU C Library.  */
+  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+  tdep->gregset_reg_offset = amd64_gnu_gregset_reg_offset;
+  tdep->gregset_num_regs = ARRAY_SIZE (amd64_gnu_gregset_reg_offset);
+  tdep->sizeof_gregset = 21 * 8; /* sizeof (struct i386_thread_state); */
+
+  tdep->sigtramp_p = amd64_gnu_sigtramp_p;
+  tdep->sigcontext_addr = amd64_gnu_sigcontext_addr;
+  tdep->sc_reg_offset = amd64_gnu_sc_reg_offset;
+  tdep->sc_num_regs = ARRAY_SIZE (amd64_gnu_sc_reg_offset);
+
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_solib_svr4_fetch_link_map_offsets
+    (gdbarch, svr4_lp64_fetch_link_map_offsets);
+}
+
+void _initialize_amd64_gnu_tdep ();
+void
+_initialize_amd64_gnu_tdep ()
+{
+  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
+			  GDB_OSABI_HURD, amd64_gnu_init_abi);
+}
diff --git a/gdb/config/i386/nm-i386gnu.h b/gdb/config/i386/nm-x86-gnu.h
similarity index 83%
rename from gdb/config/i386/nm-i386gnu.h
rename to gdb/config/i386/nm-x86-gnu.h
index d2d5de83948..ed4d1729227 100644
--- a/gdb/config/i386/nm-i386gnu.h
+++ b/gdb/config/i386/nm-x86-gnu.h
@@ -22,9 +22,16 @@
 /* Thread flavors used in re-setting the T bit.  */
 #define THREAD_STATE_FLAVOR		i386_REGS_SEGS_STATE
 #define THREAD_STATE_SIZE		i386_THREAD_STATE_COUNT
+#ifdef __x86_64__
+#define THREAD_STATE_SET_TRACED(state) \
+	((struct i386_thread_state *) (state))->rfl |= 0x100
+#define THREAD_STATE_CLEAR_TRACED(state) \
+	((((struct i386_thread_state *) (state))->rfl &= ~0x100), 1)
+#else
 #define THREAD_STATE_SET_TRACED(state) \
   	((struct i386_thread_state *) (state))->efl |= 0x100
 #define THREAD_STATE_CLEAR_TRACED(state) \
   	((((struct i386_thread_state *) (state))->efl &= ~0x100), 1)
+#endif /* __x86_64__ */
 
 #endif /* CONFIG_I386_NM_I386GNU_H */
diff --git a/gdb/config/i386/i386gnu.mn b/gdb/config/i386/x86-gnu.mn
similarity index 100%
rename from gdb/config/i386/i386gnu.mn
rename to gdb/config/i386/x86-gnu.mn
diff --git a/gdb/configure.host b/gdb/configure.host
index da71675b201..999af8e59ae 100644
--- a/gdb/configure.host
+++ b/gdb/configure.host
@@ -184,6 +184,7 @@ x86_64-*-mingw*)        gdb_host=mingw64
 			gdb_host_obs=mingw-hdep.o
 			;;
 x86_64-*-cygwin*)	gdb_host=cygwin64 ;;
+x86_64-*-gnu*)		gdb_host=gnu64 ;;
 m32r*-*-linux*)          gdb_host=linux ;;
 
 xtensa*-*-linux*)	gdb_host=linux ;;
diff --git a/gdb/configure.nat b/gdb/configure.nat
index 8b98511cef7..ef404fb791a 100644
--- a/gdb/configure.nat
+++ b/gdb/configure.nat
@@ -211,23 +211,44 @@ case ${gdb_host} in
 		;;
 	esac
 	;;
+    gnu64)
+	case ${gdb_host_cpu} in
+	    i386)
+		# Host: x86_64 running the GNU Hurd
+		NATDEPFILES='x86-gnu-nat.o gnu-nat.o \
+		     x86-nat.o nat/x86-dregs.o nat/x86-xstate.o \
+		     amd64-nat.o fork-child.o \
+		     nat/fork-inferior.o \
+		     notify_S.o process_reply_S.o msg_reply_S.o \
+		     msg_U.o exc_request_U.o exc_request_S.o'
+		HAVE_NATIVE_GCORE_HOST=1
+
+		NAT_FILE='nm-x86-gnu.h'
+		MH_CFLAGS='-D_GNU_SOURCE'
+
+		XM_CLIBS='-lshouldbeinlibc'
+
+		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/x86-gnu.mn"
+		;;
+	esac
+	;;
     i386gnu)
 	case ${gdb_host_cpu} in
 	    i386)
 		# Host: Intel 386 running the GNU Hurd
-		NATDEPFILES='i386-gnu-nat.o gnu-nat.o \
+		NATDEPFILES='x86-gnu-nat.o gnu-nat.o \
 		     x86-nat.o nat/x86-dregs.o fork-child.o \
 		     nat/fork-inferior.o \
 		     notify_S.o process_reply_S.o msg_reply_S.o \
 		     msg_U.o exc_request_U.o exc_request_S.o'
 		HAVE_NATIVE_GCORE_HOST=1
 
-		NAT_FILE='nm-i386gnu.h'
+		NAT_FILE='nm-x86-gnu.h'
 		MH_CFLAGS='-D_GNU_SOURCE'
 
 		XM_CLIBS='-lshouldbeinlibc'
 
-		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/i386gnu.mn"
+		nat_makefile_frag="${srcdir}/config/${gdb_host_cpu}/x86-gnu.mn"
 		;;
 	esac
 	;;
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 47a674201f9..df9e9917ad1 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -328,7 +328,7 @@ i[34567]86-*-linux*)
 	;;
 i[34567]86-*-gnu*)
 	# Target: Intel 386 running the GNU Hurd
-	gdb_target_obs="i386-gnu-tdep.o solib-svr4.o"
+	gdb_target_obs="i386-gnu-tdep.o glibc-tdep.o solib-svr4.o"
 	;;
 i[34567]86-*-cygwin*)
 	# Target: Intel 386 running win32
@@ -744,6 +744,10 @@ x86_64-*-openbsd*)
 x86_64-*-rtems*)
 	gdb_target_obs="${amd64_tobjs} ${i386_tobjs} i386-bsd-tdep.o"
 	;;
+x86_64-*-gnu*)
+	# Target: x86_64 running the GNU Hurd
+	gdb_target_obs="amd64-gnu-tdep.o glibc-tdep.o solib-svr4.o"
+	;;
 xtensa*-*-*linux*)
 	# Target: GNU/Linux Xtensa
 	gdb_target_obs="xtensa-linux-tdep.o symfile-mem.o linux-tdep.o"
diff --git a/gdb/i386-gnu-tdep.c b/gdb/i386-gnu-tdep.c
index 9ff47147513..b94e23670de 100644
--- a/gdb/i386-gnu-tdep.c
+++ b/gdb/i386-gnu-tdep.c
@@ -21,6 +21,7 @@
 #include "osabi.h"
 #include "solib-svr4.h"
 
+#include "glibc-tdep.h"
 #include "i386-tdep.h"
 
 /* Recognizing signal handler frames.  */
@@ -72,8 +73,7 @@ i386_gnu_sigtramp_start (frame_info_ptr this_frame)
   return pc;
 }
 
-/* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp
-   routine.  */
+/* Return whether THIS_FRAME corresponds to a Hurd sigtramp routine.  */
 
 static int
 i386_gnu_sigtramp_p (frame_info_ptr this_frame)
@@ -178,9 +178,18 @@ i386gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   /* GNU uses ELF.  */
   i386_elf_init_abi (info, gdbarch);
 
+  /* Hurd uses SVR4-style shared libraries.  */
+  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
   set_solib_svr4_fetch_link_map_offsets
     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 
+  /* Hurd uses the dynamic linker included in the GNU C Library.  */
+  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+					     svr4_fetch_objfile_link_map);
+
   tdep->gregset_reg_offset = i386gnu_gregset_reg_offset;
   tdep->gregset_num_regs = ARRAY_SIZE (i386gnu_gregset_reg_offset);
   tdep->sizeof_gregset = 19 * 4;
diff --git a/gdb/i386-gnu-nat.c b/gdb/x86-gnu-nat.c
similarity index 69%
rename from gdb/i386-gnu-nat.c
rename to gdb/x86-gnu-nat.c
index 0b0759179aa..15a92fbdb39 100644
--- a/gdb/i386-gnu-nat.c
+++ b/gdb/x86-gnu-nat.c
@@ -35,7 +35,13 @@ extern "C"
 #include "floatformat.h"
 #include "regcache.h"
 
+
+#ifdef __x86_64__
+#include "amd64-tdep.h"
+#include "amd64-nat.h"
+#else
 #include "i386-tdep.h"
+#endif
 
 #include "inf-child.h"
 #include "i387-tdep.h"
@@ -43,21 +49,82 @@ extern "C"
 /* Offset to the thread_state_t location where REG is stored.  */
 #define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
 
+#ifdef __x86_64__
+
 /* At REG_OFFSET[N] is the offset to the thread_state_t location where
    the GDB register N is stored.  */
-static int reg_offset[] =
+static int amd64_gnu_thread_state_reg_offset[] =
 {
-  REG_OFFSET (eax), REG_OFFSET (ecx), REG_OFFSET (edx), REG_OFFSET (ebx),
-  REG_OFFSET (uesp), REG_OFFSET (ebp), REG_OFFSET (esi), REG_OFFSET (edi),
-  REG_OFFSET (eip), REG_OFFSET (efl), REG_OFFSET (cs), REG_OFFSET (ss),
-  REG_OFFSET (ds), REG_OFFSET (es), REG_OFFSET (fs), REG_OFFSET (gs)
+  REG_OFFSET (rax),		/* %rax */
+  REG_OFFSET (rbx),		/* %rbx */
+  REG_OFFSET (rcx),		/* %rcx */
+  REG_OFFSET (rdx),		/* %rdx */
+  REG_OFFSET (rsi),		/* %rsi */
+  REG_OFFSET (rdi),		/* %rdi */
+  REG_OFFSET (rbp),		/* %rbp */
+  REG_OFFSET (ursp),	/* %rsp */
+  REG_OFFSET (r8),		/* %r8 ...  */
+  REG_OFFSET (r9),
+  REG_OFFSET (r10),
+  REG_OFFSET (r11),
+  REG_OFFSET (r12),
+  REG_OFFSET (r13),
+  REG_OFFSET (r14),
+  REG_OFFSET (r15),		/* ... %r15 */
+  REG_OFFSET (rip),		/* %rip */
+  REG_OFFSET (rfl),		/* %rflags */
+  REG_OFFSET (cs)	    /* %cs */
 };
 
-#define REG_ADDR(state, regnum) ((char *)(state) + reg_offset[regnum])
+static const int amd64_gnu_thread_state_num_regs =
+  ARRAY_SIZE (amd64_gnu_thread_state_reg_offset);
+
+#define REG_ADDR(state, regnum) \
+  ((char *)(state) + amd64_gnu_thread_state_reg_offset[regnum])
+#define VALID_REGISTER(regnum) \
+  ((regnum) >= 0 && (regnum) < amd64_gnu_thread_state_num_regs)
+#define NUM_GREGS amd64_gnu_thread_state_num_regs
+#define FLAGS_REGISTER rfl
+
+#else
+
+/* At REG_OFFSET[N] is the offset to the thread_state_t location where
+   the GDB register N is stored.  */
+static int i386_gnu_thread_state_reg_offset[] =
+{
+  REG_OFFSET (eax),	/* %eax */
+  REG_OFFSET (ecx),	/* %ecx */
+  REG_OFFSET (edx),	/* %edx */
+  REG_OFFSET (ebx),	/* %ebx */
+  REG_OFFSET (uesp),	/* %esp */
+  REG_OFFSET (ebp),	/* %ebp */
+  REG_OFFSET (esi),	/* %esi */
+  REG_OFFSET (edi),	/* %edi */
+  REG_OFFSET (eip),	/* %eip */
+  REG_OFFSET (efl),	/* %efl */
+  REG_OFFSET (cs),	/* %cs */
+  REG_OFFSET (ss),	/* %ss */
+  REG_OFFSET (ds),	/* %ds */
+  REG_OFFSET (es),	/* %es */
+  REG_OFFSET (fs),	/* %fs */
+  REG_OFFSET (gs)	/* gs */
+};
+
+static const int i386_gnu_thread_state_num_regs =
+  ARRAY_SIZE (i386_gnu_thread_state_reg_offset);
+
+#define REG_ADDR(state, regnum) \
+  ((char *)(state) + i386_gnu_thread_state_reg_offset[regnum])
+#define VALID_REGISTER(regnum) \
+  ((regnum) >= 0 && (regnum) < i386_gnu_thread_state_num_regs)
+#define NUM_GREGS i386_gnu_thread_state_num_regs
+#define FLAGS_REGISTER efl
+
+#endif  /* __x86_64__ */
 
 \f
 
-/* The i386 GNU Hurd target.  */
+/* The x86 GNU Hurd target.  */
 
 #ifdef i386_DEBUG_STATE
 using gnu_base_target = x86_nat_target<gnu_nat_target>;
@@ -65,13 +132,13 @@ using gnu_base_target = x86_nat_target<gnu_nat_target>;
 using gnu_base_target = gnu_nat_target;
 #endif
 
-struct i386_gnu_nat_target final : public gnu_base_target
+struct x86_gnu_nat_target final : public gnu_base_target
 {
   void fetch_registers (struct regcache *, int) override;
   void store_registers (struct regcache *, int) override;
 };
 
-static i386_gnu_nat_target the_i386_gnu_nat_target;
+static x86_gnu_nat_target the_x86_gnu_nat_target;
 
 /* Get the whole floating-point state of THREAD and record the values
    of the corresponding (pseudo) registers.  */
@@ -106,7 +173,7 @@ fetch_fpregs (struct regcache *regcache, struct proc *thread)
 
 /* Fetch register REGNO, or all regs if REGNO is -1.  */
 void
-i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
+x86_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 {
   struct proc *thread;
   ptid_t ptid = regcache->ptid ();
@@ -119,7 +186,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
     error (_("Can't fetch registers from thread %s: No such thread"),
 	   target_pid_to_str (ptid).c_str ());
 
-  if (regno < I386_NUM_GREGS || regno == -1)
+  if (VALID_REGISTER (regno) || regno == -1)
     {
       thread_state_t state;
 
@@ -138,7 +205,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 
 	  proc_debug (thread, "fetching all register");
 
-	  for (i = 0; i < I386_NUM_GREGS; i++)
+	  for (i = 0; i < NUM_GREGS; i++)
 	    regcache->raw_supply (i, REG_ADDR (state, i));
 	  thread->fetched_regs = ~0;
 	}
@@ -153,7 +220,7 @@ i386_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
 	}
     }
 
-  if (regno >= I386_NUM_GREGS || regno == -1)
+  if (!VALID_REGISTER(regno) || regno == -1)
     {
       proc_debug (thread, "fetching floating-point registers");
 
@@ -196,7 +263,7 @@ store_fpregs (const struct regcache *regcache, struct proc *thread, int regno)
 
 /* Store at least register REGNO, or all regs if REGNO == -1.  */
 void
-i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
+x86_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 {
   struct proc *thread;
   struct gdbarch *gdbarch = regcache->arch ();
@@ -210,7 +277,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
     error (_("Couldn't store registers into thread %s: No such thread"),
 	   target_pid_to_str (ptid).c_str ());
 
-  if (regno < I386_NUM_GREGS || regno == -1)
+  if (VALID_REGISTER (regno) || regno == -1)
     {
       thread_state_t state;
       thread_state_data_t old_state;
@@ -231,14 +298,14 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 
       /* Save the T bit.  We might try to restore the %eflags register
 	 below, but changing the T bit would seriously confuse GDB.  */
-      trace = ((struct i386_thread_state *)state)->efl & 0x100;
+      trace = ((struct i386_thread_state *)state)->FLAGS_REGISTER & 0x100;
 
       if (!was_aborted && was_valid)
 	/* See which registers have changed after aborting the thread.  */
 	{
 	  int check_regno;
 
-	  for (check_regno = 0; check_regno < I386_NUM_GREGS; check_regno++)
+	  for (check_regno = 0; check_regno < NUM_GREGS; check_regno++)
 	    if ((thread->fetched_regs & (1 << check_regno))
 		&& memcpy (REG_ADDR (&old_state, check_regno),
 			   REG_ADDR (state, check_regno),
@@ -263,7 +330,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 
 	  proc_debug (thread, "storing all registers");
 
-	  for (i = 0; i < I386_NUM_GREGS; i++)
+	  for (i = 0; i < NUM_GREGS; i++)
 	    if (REG_VALID == regcache->get_register_status (i))
 	      regcache->raw_collect (i, REG_ADDR (state, i));
 	}
@@ -277,11 +344,11 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 	}
 
       /* Restore the T bit.  */
-      ((struct i386_thread_state *)state)->efl &= ~0x100;
-      ((struct i386_thread_state *)state)->efl |= trace;
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER &= ~0x100;
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER |= trace;
     }
 
-  if (regno >= I386_NUM_GREGS || regno == -1)
+  if (!VALID_REGISTER (regno) || regno == -1)
     {
       proc_debug (thread, "storing floating-point registers");
 
@@ -296,7 +363,7 @@ i386_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
 /* Get debug registers for thread THREAD.  */
 
 static void
-i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
+x86_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 {
   mach_msg_type_number_t count = i386_DEBUG_STATE_COUNT;
   kern_return_t err;
@@ -311,7 +378,7 @@ i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 /* Set debug registers for thread THREAD.  */
 
 static void
-i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
+x86_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 {
   kern_return_t err;
 
@@ -325,23 +392,23 @@ i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 /* Set DR_CONTROL in THREAD.  */
 
 static void
-i386_gnu_dr_set_control_one (struct proc *thread, void *arg)
+x86_gnu_dr_set_control_one (struct proc *thread, void *arg)
 {
   unsigned long *control = (unsigned long *) arg;
   struct i386_debug_state regs;
 
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
   regs.dr[DR_CONTROL] = *control;
-  i386_gnu_dr_set (&regs, thread);
+  x86_gnu_dr_set (&regs, thread);
 }
 
 /* Set DR_CONTROL to CONTROL in all threads.  */
 
 static void
-i386_gnu_dr_set_control (unsigned long control)
+x86_gnu_dr_set_control (unsigned long control)
 {
   inf_update_procs (gnu_current_inf);
-  inf_threads (gnu_current_inf, i386_gnu_dr_set_control_one, &control);
+  inf_threads (gnu_current_inf, x86_gnu_dr_set_control_one, &control);
 }
 
 /* Parameters to set a debugging address.  */
@@ -355,20 +422,20 @@ struct reg_addr
 /* Set address REGNUM (zero based) to ADDR in THREAD.  */
 
 static void
-i386_gnu_dr_set_addr_one (struct proc *thread, void *arg)
+x86_gnu_dr_set_addr_one (struct proc *thread, void *arg)
 {
   struct reg_addr *reg_addr = (struct reg_addr *) arg;
   struct i386_debug_state regs;
 
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
   regs.dr[reg_addr->regnum] = reg_addr->addr;
-  i386_gnu_dr_set (&regs, thread);
+  x86_gnu_dr_set (&regs, thread);
 }
 
 /* Set address REGNUM (zero based) to ADDR in all threads.  */
 
 static void
-i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
+x86_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
 {
   struct reg_addr reg_addr;
 
@@ -378,13 +445,13 @@ i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
   reg_addr.addr = addr;
 
   inf_update_procs (gnu_current_inf);
-  inf_threads (gnu_current_inf, i386_gnu_dr_set_addr_one, &reg_addr);
+  inf_threads (gnu_current_inf, x86_gnu_dr_set_addr_one, &reg_addr);
 }
 
 /* Get debug register REGNUM value from only the one LWP of PTID.  */
 
 static unsigned long
-i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
+x86_gnu_dr_get_reg (ptid_t ptid, int regnum)
 {
   struct i386_debug_state regs;
   struct proc *thread;
@@ -393,7 +460,7 @@ i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
   inf_update_procs (gnu_current_inf);
 
   thread = inf_tid_to_thread (gnu_current_inf, ptid.lwp ());
-  i386_gnu_dr_get (&regs, thread);
+  x86_gnu_dr_get (&regs, thread);
 
   return regs.dr[regnum];
 }
@@ -401,46 +468,50 @@ i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
 /* Return the inferior's debug register REGNUM.  */
 
 static CORE_ADDR
-i386_gnu_dr_get_addr (int regnum)
+x86_gnu_dr_get_addr (int regnum)
 {
   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 
-  return i386_gnu_dr_get_reg (inferior_ptid, regnum);
+  return x86_gnu_dr_get_reg (inferior_ptid, regnum);
 }
 
 /* Get DR_STATUS from only the one thread of INFERIOR_PTID.  */
 
 static unsigned long
-i386_gnu_dr_get_status (void)
+x86_gnu_dr_get_status (void)
 {
-  return i386_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
 }
 
 /* Return the inferior's DR7 debug control register.  */
 
 static unsigned long
-i386_gnu_dr_get_control (void)
+x86_gnu_dr_get_control (void)
 {
-  return i386_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
 }
 #endif /* i386_DEBUG_STATE */
 
-void _initialize_i386gnu_nat ();
+void _initialize_x86_gnu_nat ();
 void
-_initialize_i386gnu_nat ()
+_initialize_x86_gnu_nat ()
 {
 #ifdef i386_DEBUG_STATE
-  x86_dr_low.set_control = i386_gnu_dr_set_control;
+  x86_dr_low.set_control = x86_gnu_dr_set_control;
   gdb_assert (DR_FIRSTADDR == 0 && DR_LASTADDR < i386_DEBUG_STATE_COUNT);
-  x86_dr_low.set_addr = i386_gnu_dr_set_addr;
-  x86_dr_low.get_addr = i386_gnu_dr_get_addr;
-  x86_dr_low.get_status = i386_gnu_dr_get_status;
-  x86_dr_low.get_control = i386_gnu_dr_get_control;
+  x86_dr_low.set_addr = x86_gnu_dr_set_addr;
+  x86_dr_low.get_addr = x86_gnu_dr_get_addr;
+  x86_dr_low.get_status = x86_gnu_dr_get_status;
+  x86_dr_low.get_control = x86_gnu_dr_get_control;
+#ifdef __x86_64__
+  x86_set_debug_register_length (8);
+#else
   x86_set_debug_register_length (4);
+#endif
 #endif /* i386_DEBUG_STATE */
 
-  gnu_target = &the_i386_gnu_nat_target;
+  gnu_target = &the_x86_gnu_nat_target;
 
   /* Register the target.  */
-  add_inf_child_target (&the_i386_gnu_nat_target);
+  add_inf_child_target (&the_x86_gnu_nat_target);
 }
-- 
2.39.2

Re: [PATCH v2] Port GDB to Hurd x86_64.

[John Baldwin]

On 2/23/24 9:28 PM, Flavio Cruz wrote:
> This port extends the existing i686 port to support x86_64 by trying to
> reuse existing code whenever it makes sense.
> 
> * gdb/amd64-gnu-tdep.c: Adds logic for handling signal frames and
>    position of amd64 registers in the different Hurd structs.
>    The signal code is very similar to i686, except the trampoline code
>    is adapted.
> * gdb/config/i386/nm-i386gnu.h: renamed to gdb/config/i386/nm-x86-gnu.h
>    and adapt it for x86_64.
> * gdb/config/i386/i386gnu.mn: renamed to gdb/config/i386/nm-x86-gnu.mn
>    and reuse it for x86_64.
> * gdb/configure.host: recognize gnu64 as a host.
> * gdb/configure.nat: recognize gnu64 host and update existing i386gnu to
>    reuse the new shared files.
> * gdb/configure.tgt: recognize x86_64-*-gnu* triplet and use
>    amd64-gnu-tdep.c.
> * gdb/i386-gnu-tdep.c: added i386_gnu_thread_state_reg_offset that is
>    copied from i386-gnu-nat.c. This makes it similar to amd64.
> * gdb/i386-gnu-nat.c: rename it to x86-gnu-nat.c since we reuse this for
>    i386 and amd64. Updated REG_ADDR to use one of the structures. Added
>    VALID_REGISTER to make sure it's a register we can provide at this time
>    (not all of them are available in amd64). FLAGS_REGISTER is either rfl
>    or efl depending on the arch. Renamed functions and class from i386 to x86
>    whenever they can be reused.
> 
> Tested on Hurd x86_64 and i686.
> ---
> 
> I addressed John's comments and moved amd64_gnu_thread_state_* and
> i386_gnu_thread_state_* to x86-gnu-nat.c. The new patch also contains a few
> changes that makes backtracing through shared libraries work.

Thanks, this generally looks ok to me.

One question I have is if you need nat/x86-xstate.o for the native Hurd x86_64
target?  The i686 target doesn't use it and I didn't see any references in
the patches to XSAVE support, so I suspect you don't need it.  Were you getting
a link error without it, or is it something you copied from Linux x86_64?  If
the latter, it is probably best to drop it for now until you add XSAVE support
in the future (which would presumably apply to both i686 and x86_64).

Reviewed-By: John Baldwin <jhb@FreeBSD.org>

-- 
John Baldwin