Port GDB to Hurd x86_64.

This port extends the existing i686 port to support x86_64 by reusing
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.

1 files changed, 516 insertions, 0 deletions

diff --git a/gdb/x86-gnu-nat.c b/gdb/x86-gnu-nat.c
new file mode 100644
index 0000000..da3b7e9
--- /dev/null
+++ b/gdb/x86-gnu-nat.c
@@ -0,0 +1,516 @@
+/* Low level interface to i386 running the GNU Hurd.
+
+   Copyright (C) 1992-2024 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 this first, to pick up the <mach.h> 'thread_info' diversion.  */
+#include "gnu-nat.h"
+
+/* Mach/Hurd headers are not yet ready for C++ compilation.  */
+extern "C"
+{
+#include <mach.h>
+#include <mach_error.h>
+#include <mach/message.h>
+#include <mach/exception.h>
+}
+
+#include "x86-nat.h"
+#include "inferior.h"
+#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"
+
+/* 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 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 */
+};
+
+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__ */
+
+
+
+/* The x86 GNU Hurd target.  */
+
+#ifdef i386_DEBUG_STATE
+using gnu_base_target = x86_nat_target<gnu_nat_target>;
+#else
+using gnu_base_target = gnu_nat_target;
+#endif
+
+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 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.  */
+
+static void
+fetch_fpregs (struct regcache *regcache, struct proc *thread)
+{
+  mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
+  struct i386_float_state state;
+  kern_return_t err;
+
+  err = thread_get_state (thread->port, i386_FLOAT_STATE,
+			  (thread_state_t) &state, &count);
+  if (err)
+    {
+      warning (_("Couldn't fetch floating-point state from %s"),
+	       proc_string (thread));
+      return;
+    }
+
+  if (!state.initialized)
+    {
+      /* The floating-point state isn't initialized.  */
+      i387_supply_fsave (regcache, -1, NULL);
+    }
+  else
+    {
+      /* Supply the floating-point registers.  */
+      i387_supply_fsave (regcache, -1, state.hw_state);
+    }
+}
+
+/* Fetch register REGNO, or all regs if REGNO is -1.  */
+void
+x86_gnu_nat_target::fetch_registers (struct regcache *regcache, int regno)
+{
+  struct proc *thread;
+  ptid_t ptid = regcache->ptid ();
+
+  /* Make sure we know about new threads.  */
+  inf_update_procs (gnu_current_inf);
+
+  thread = inf_tid_to_thread (gnu_current_inf, ptid.lwp ());
+  if (!thread)
+    error (_("Can't fetch registers from thread %s: No such thread"),
+	   target_pid_to_str (ptid).c_str ());
+
+  if (VALID_REGISTER (regno) || regno == -1)
+    {
+      thread_state_t state;
+
+      /* This does the dirty work for us.  */
+      state = proc_get_state (thread, 0);
+      if (!state)
+	{
+	  warning (_("Couldn't fetch registers from %s"),
+		   proc_string (thread));
+	  return;
+	}
+
+      if (regno == -1)
+	{
+	  int i;
+
+	  proc_debug (thread, "fetching all register");
+
+	  for (i = 0; i < NUM_GREGS; i++)
+	    regcache->raw_supply (i, REG_ADDR (state, i));
+	  thread->fetched_regs = ~0;
+	}
+      else
+	{
+	  proc_debug (thread, "fetching register %s",
+		      gdbarch_register_name (regcache->arch (),
+					     regno));
+
+	  regcache->raw_supply (regno, REG_ADDR (state, regno));
+	  thread->fetched_regs |= (1 << regno);
+	}
+    }
+
+  if (!VALID_REGISTER(regno) || regno == -1)
+    {
+      proc_debug (thread, "fetching floating-point registers");
+
+      fetch_fpregs (regcache, thread);
+    }
+}
+
+
+/* Store the whole floating-point state into THREAD using information
+   from the corresponding (pseudo) registers.  */
+static void
+store_fpregs (const struct regcache *regcache, struct proc *thread, int regno)
+{
+  mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
+  struct i386_float_state state;
+  kern_return_t err;
+
+  err = thread_get_state (thread->port, i386_FLOAT_STATE,
+			  (thread_state_t) &state, &count);
+  if (err)
+    {
+      warning (_("Couldn't fetch floating-point state from %s"),
+	       proc_string (thread));
+      return;
+    }
+
+  /* FIXME: kettenis/2001-07-15: Is this right?  Should we somehow
+     take into account DEPRECATED_REGISTER_VALID like the old code did?  */
+  i387_collect_fsave (regcache, regno, state.hw_state);
+
+  err = thread_set_state (thread->port, i386_FLOAT_STATE,
+			  (thread_state_t) &state, i386_FLOAT_STATE_COUNT);
+  if (err)
+    {
+      warning (_("Couldn't store floating-point state into %s"),
+	       proc_string (thread));
+      return;
+    }
+}
+
+/* Store at least register REGNO, or all regs if REGNO == -1.  */
+void
+x86_gnu_nat_target::store_registers (struct regcache *regcache, int regno)
+{
+  struct proc *thread;
+  struct gdbarch *gdbarch = regcache->arch ();
+  ptid_t ptid = regcache->ptid ();
+
+  /* Make sure we know about new threads.  */
+  inf_update_procs (gnu_current_inf);
+
+  thread = inf_tid_to_thread (gnu_current_inf, ptid.lwp ());
+  if (!thread)
+    error (_("Couldn't store registers into thread %s: No such thread"),
+	   target_pid_to_str (ptid).c_str ());
+
+  if (VALID_REGISTER (regno) || regno == -1)
+    {
+      thread_state_t state;
+      thread_state_data_t old_state;
+      int was_aborted = thread->aborted;
+      int was_valid = thread->state_valid;
+      int trace;
+
+      if (!was_aborted && was_valid)
+	memcpy (&old_state, &thread->state, sizeof (old_state));
+
+      state = proc_get_state (thread, 1);
+      if (!state)
+	{
+	  warning (_("Couldn't store registers into %s"),
+		   proc_string (thread));
+	  return;
+	}
+
+      /* 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)->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 < NUM_GREGS; check_regno++)
+	    if ((thread->fetched_regs & (1 << check_regno))
+		&& memcpy (REG_ADDR (&old_state, check_regno),
+			   REG_ADDR (state, check_regno),
+			   register_size (gdbarch, check_regno)))
+	      /* Register CHECK_REGNO has changed!  Ack!  */
+	      {
+		warning (_("Register %s changed after the thread was aborted"),
+			 gdbarch_register_name (gdbarch, check_regno));
+		if (regno >= 0 && regno != check_regno)
+		  /* Update GDB's copy of the register.  */
+		  regcache->raw_supply (check_regno,
+					REG_ADDR (state, check_regno));
+		else
+		  warning (_("... also writing this register!  "
+			     "Suspicious..."));
+	      }
+	}
+
+      if (regno == -1)
+	{
+	  int i;
+
+	  proc_debug (thread, "storing all registers");
+
+	  for (i = 0; i < NUM_GREGS; i++)
+	    if (REG_VALID == regcache->get_register_status (i))
+	      regcache->raw_collect (i, REG_ADDR (state, i));
+	}
+      else
+	{
+	  proc_debug (thread, "storing register %s",
+		      gdbarch_register_name (gdbarch, regno));
+
+	  gdb_assert (REG_VALID == regcache->get_register_status (regno));
+	  regcache->raw_collect (regno, REG_ADDR (state, regno));
+	}
+
+      /* Restore the T bit.  */
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER &= ~0x100;
+      ((struct i386_thread_state *)state)->FLAGS_REGISTER |= trace;
+    }
+
+  if (!VALID_REGISTER (regno) || regno == -1)
+    {
+      proc_debug (thread, "storing floating-point registers");
+
+      store_fpregs (regcache, thread, regno);
+    }
+}
+
+
+/* Support for debug registers.  */
+
+#ifdef i386_DEBUG_STATE
+/* Get debug registers for thread THREAD.  */
+
+static void
+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;
+
+  err = thread_get_state (thread->port, i386_DEBUG_STATE,
+			  (thread_state_t) regs, &count);
+  if (err != 0 || count != i386_DEBUG_STATE_COUNT)
+    warning (_("Couldn't fetch debug state from %s"),
+	     proc_string (thread));
+}
+
+/* Set debug registers for thread THREAD.  */
+
+static void
+x86_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
+{
+  kern_return_t err;
+
+  err = thread_set_state (thread->port, i386_DEBUG_STATE,
+			  (thread_state_t) regs, i386_DEBUG_STATE_COUNT);
+  if (err != 0)
+    warning (_("Couldn't store debug state into %s"),
+	     proc_string (thread));
+}
+
+/* Set DR_CONTROL in THREAD.  */
+
+static void
+x86_gnu_dr_set_control_one (struct proc *thread, void *arg)
+{
+  unsigned long *control = (unsigned long *) arg;
+  struct i386_debug_state regs;
+
+  x86_gnu_dr_get (&regs, thread);
+  regs.dr[DR_CONTROL] = *control;
+  x86_gnu_dr_set (&regs, thread);
+}
+
+/* Set DR_CONTROL to CONTROL in all threads.  */
+
+static void
+x86_gnu_dr_set_control (unsigned long control)
+{
+  inf_update_procs (gnu_current_inf);
+  inf_threads (gnu_current_inf, x86_gnu_dr_set_control_one, &control);
+}
+
+/* Parameters to set a debugging address.  */
+
+struct reg_addr
+{
+  int regnum;		/* Register number (zero based).  */
+  CORE_ADDR addr;	/* Address.  */
+};
+
+/* Set address REGNUM (zero based) to ADDR in THREAD.  */
+
+static void
+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;
+
+  x86_gnu_dr_get (&regs, thread);
+  regs.dr[reg_addr->regnum] = reg_addr->addr;
+  x86_gnu_dr_set (&regs, thread);
+}
+
+/* Set address REGNUM (zero based) to ADDR in all threads.  */
+
+static void
+x86_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
+{
+  struct reg_addr reg_addr;
+
+  gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
+
+  reg_addr.regnum = regnum;
+  reg_addr.addr = addr;
+
+  inf_update_procs (gnu_current_inf);
+  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
+x86_gnu_dr_get_reg (ptid_t ptid, int regnum)
+{
+  struct i386_debug_state regs;
+  struct proc *thread;
+
+  /* Make sure we know about new threads.  */
+  inf_update_procs (gnu_current_inf);
+
+  thread = inf_tid_to_thread (gnu_current_inf, ptid.lwp ());
+  x86_gnu_dr_get (&regs, thread);
+
+  return regs.dr[regnum];
+}
+
+/* Return the inferior's debug register REGNUM.  */
+
+static CORE_ADDR
+x86_gnu_dr_get_addr (int regnum)
+{
+  gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
+
+  return x86_gnu_dr_get_reg (inferior_ptid, regnum);
+}
+
+/* Get DR_STATUS from only the one thread of INFERIOR_PTID.  */
+
+static unsigned long
+x86_gnu_dr_get_status (void)
+{
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
+}
+
+/* Return the inferior's DR7 debug control register.  */
+
+static unsigned long
+x86_gnu_dr_get_control (void)
+{
+  return x86_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
+}
+#endif /* i386_DEBUG_STATE */
+
+void _initialize_x86_gnu_nat ();
+void
+_initialize_x86_gnu_nat ()
+{
+#ifdef i386_DEBUG_STATE
+  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 = 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_x86_gnu_nat_target;
+
+  /* Register the target.  */
+  add_inf_child_target (&the_x86_gnu_nat_target);
+}