-/* Support for debug registers. */
-
-/* Get debug register REGNUM value from only the one LWP of PTID. */
-
-static unsigned long
-x86_linux_dr_get (ptid_t ptid, int regnum)
-{
- int tid;
- unsigned long value;
-
- tid = ptid_get_lwp (ptid);
- if (tid == 0)
- tid = ptid_get_pid (ptid);
-
- errno = 0;
- value = ptrace (PTRACE_PEEKUSER, tid,
- offsetof (struct user, u_debugreg[regnum]), 0);
- if (errno != 0)
- perror_with_name (_("Couldn't read debug register"));
-
- return value;
-}
-
-/* Set debug register REGNUM to VALUE in only the one LWP of PTID. */
-
-static void
-x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
-{
- int tid;
-
- tid = ptid_get_lwp (ptid);
- if (tid == 0)
- tid = ptid_get_pid (ptid);
-
- errno = 0;
- ptrace (PTRACE_POKEUSER, tid,
- offsetof (struct user, u_debugreg[regnum]), value);
- if (errno != 0)
- perror_with_name (_("Couldn't write debug register"));
-}
-
-/* Return the inferior's debug register REGNUM. */
-
-static CORE_ADDR
-x86_linux_dr_get_addr (int regnum)
-{
- /* DR6 and DR7 are retrieved with some other way. */
- gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
-
- return x86_linux_dr_get (inferior_ptid, regnum);
-}
-
-/* Return the inferior's DR7 debug control register. */
-
-static unsigned long
-x86_linux_dr_get_control (void)
-{
- return x86_linux_dr_get (inferior_ptid, DR_CONTROL);
-}
-
-/* Get DR_STATUS from only the one LWP of INFERIOR_PTID. */
-
-static unsigned long
-x86_linux_dr_get_status (void)
-{
- return x86_linux_dr_get (inferior_ptid, DR_STATUS);
-}
-
-/* Callback for iterate_over_lwps. Update the debug registers of
- LWP. */
-
-static int
-update_debug_registers_callback (struct lwp_info *lwp, void *arg)
-{
- if (lwp->arch_private == NULL)
- lwp->arch_private = XCNEW (struct arch_lwp_info);
-
- /* The actual update is done later just before resuming the lwp, we
- just mark that the registers need updating. */
- lwp->arch_private->debug_registers_changed = 1;
-
- /* If the lwp isn't stopped, force it to momentarily pause, so we
- can update its debug registers. */
- if (!lwp->stopped)
- linux_stop_lwp (lwp);
-
- /* Continue the iteration. */
- return 0;
-}
-
-/* Set DR_CONTROL to ADDR in all LWPs of the current inferior. */
-
-static void
-x86_linux_dr_set_control (unsigned long control)
-{
- ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
-
- iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
-}
-
-/* Set address REGNUM (zero based) to ADDR in all LWPs of the current
- inferior. */
-
-static void
-x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
-{
- ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
-
- gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
-
- iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
-}
-
-/* Called when resuming a thread.
- If the debug regs have changed, update the thread's copies. */
-
-static void
-x86_linux_prepare_to_resume (struct lwp_info *lwp)
-{
- int clear_status = 0;
-
- /* NULL means this is the main thread still going through the shell,
- or, no watchpoint has been set yet. In that case, there's
- nothing to do. */
- if (lwp->arch_private == NULL)
- return;
-
- if (lwp->arch_private->debug_registers_changed)
- {
- struct i386_debug_reg_state *state
- = i386_debug_reg_state (ptid_get_pid (lwp->ptid));
- int i;
-
- /* See amd64_linux_prepare_to_resume for Linux kernel note on
- i386_linux_dr_set calls ordering. */
-
- x86_linux_dr_set (lwp->ptid, DR_CONTROL, 0);
-
- for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
- if (state->dr_ref_count[i] > 0)
- {
- x86_linux_dr_set (lwp->ptid, i, state->dr_mirror[i]);
-
- /* If we're setting a watchpoint, any change the inferior
- had done itself to the debug registers needs to be
- discarded, otherwise, i386_stopped_data_address can get
- confused. */
- clear_status = 1;
- }
-
- if (state->dr_control_mirror != 0)
- x86_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror);
-
- lwp->arch_private->debug_registers_changed = 0;
- }
-
- if (clear_status || lwp->stopped_by_watchpoint)
- x86_linux_dr_set (lwp->ptid, DR_STATUS, 0);
-}
-
-static void
-x86_linux_new_thread (struct lwp_info *lp)
-{
- struct arch_lwp_info *info = XCNEW (struct arch_lwp_info);
-
- info->debug_registers_changed = 1;
-
- lp->arch_private = info;
-}
-
-/* linux_nat_new_fork hook. */
-
-static void
-x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid)
-{
- pid_t parent_pid;
- struct i386_debug_reg_state *parent_state;
- struct i386_debug_reg_state *child_state;
-
- /* NULL means no watchpoint has ever been set in the parent. In
- that case, there's nothing to do. */
- if (parent->arch_private == NULL)
- return;
-
- /* Linux kernel before 2.6.33 commit
- 72f674d203cd230426437cdcf7dd6f681dad8b0d
- will inherit hardware debug registers from parent
- on fork/vfork/clone. Newer Linux kernels create such tasks with
- zeroed debug registers.
-
- GDB core assumes the child inherits the watchpoints/hw
- breakpoints of the parent, and will remove them all from the
- forked off process. Copy the debug registers mirrors into the
- new process so that all breakpoints and watchpoints can be
- removed together. The debug registers mirror will become zeroed
- in the end before detaching the forked off process, thus making
- this compatible with older Linux kernels too. */
-
- parent_pid = ptid_get_pid (parent->ptid);
- parent_state = i386_debug_reg_state (parent_pid);
- child_state = i386_debug_reg_state (child_pid);
- *child_state = *parent_state;
-}
-
-\f
-