From 8e5d40700492597d103ebdb68eab733456b66fad Mon Sep 17 00:00:00 2001 From: Gary Benson Date: Tue, 24 Mar 2015 14:05:45 +0000 Subject: Move low-level Linux x86 debug register code to a shared file This commit moves the now-identical low-level Linux x86 debug register code from gdb/x86-linux-nat.c and gdb/gdbserver/linux-x86-low.c into a new shared file gdb/nat/x86-linux-dregs.c. gdb/ChangeLog: * nat/x86-linux-dregs.h: New file. * nat/x86-linux-dregs.c: Likewise. * Makefile.in (HFILES_NO_SRCDIR): Add nat/x86-linux-dregs.h. (x86-linux-dregs.o): New rule. * config/i386/linux.mh (NATDEPFILES): Add x86-linux-dregs.o. * config/i386/linux64.mh (NATDEPFILES): Likewise. * x86-linux-nat.c: Include nat/x86-linux-dregs.h. (u_debugreg_offset): Moved to nat/x86-linux-dregs.c. (x86_linux_dr_get): Likewise. (x86_linux_dr_set): Likewise. (x86_linux_dr_get_addr): Likewise. (x86_linux_dr_get_control): Likewise. (x86_linux_dr_get_status): Likewise. (update_debug_registers_callback): Likewise. (x86_linux_dr_set_control): Likewise. (x86_linux_dr_set_addr): Likewise. (x86_linux_update_debug_registers): Likewise. gdb/gdbserver/ChangeLog: * Makefile.in (x86-linux-dregs.o): New rule. * configure.srv: Add x86-linux-dregs.o to relevant targets. * linux-x86-low.c: Include nat/x86-linux-dregs.h. (u_debugreg_offset): Moved to nat/x86-linux-dregs.c. (x86_linux_dr_get): Likewise. (x86_linux_dr_set): Likewise. (update_debug_registers_callback): Likewise. (x86_linux_dr_set_addr): Likewise. (x86_linux_dr_get_addr): Likewise. (x86_linux_dr_set_control): Likewise. (x86_linux_dr_get_control): Likewise. (x86_linux_dr_get_status): Likewise. (x86_linux_update_debug_registers): Likewise. --- gdb/nat/x86-linux-dregs.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 gdb/nat/x86-linux-dregs.c (limited to 'gdb/nat/x86-linux-dregs.c') diff --git a/gdb/nat/x86-linux-dregs.c b/gdb/nat/x86-linux-dregs.c new file mode 100644 index 0000000..9389803 --- /dev/null +++ b/gdb/nat/x86-linux-dregs.c @@ -0,0 +1,183 @@ +/* Low-level debug register code for GNU/Linux x86 (i386 and x86-64). + + Copyright (C) 1999-2015 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 . */ + +#include "common-defs.h" +#include +#include +#include "target/waitstatus.h" +#include "nat/x86-linux.h" +#include "nat/x86-dregs.h" +#include "nat/x86-linux-dregs.h" + +/* Return the offset of REGNUM in the u_debugreg field of struct + user. */ + +static int +u_debugreg_offset (int regnum) +{ + return (offsetof (struct user, u_debugreg) + + sizeof (((struct user *) 0)->u_debugreg[0]) * regnum); +} + +/* Get debug register REGNUM value from the LWP specified by PTID. */ + +static unsigned long +x86_linux_dr_get (ptid_t ptid, int regnum) +{ + int tid; + unsigned long value; + + gdb_assert (ptid_lwp_p (ptid)); + tid = ptid_get_lwp (ptid); + + errno = 0; + value = ptrace (PTRACE_PEEKUSER, tid, u_debugreg_offset (regnum), 0); + if (errno != 0) + perror_with_name (_("Couldn't read debug register")); + + return value; +} + +/* Set debug register REGNUM to VALUE in the LWP specified by PTID. */ + +static void +x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value) +{ + int tid; + + gdb_assert (ptid_lwp_p (ptid)); + tid = ptid_get_lwp (ptid); + + errno = 0; + ptrace (PTRACE_POKEUSER, tid, u_debugreg_offset (regnum), value); + if (errno != 0) + perror_with_name (_("Couldn't write debug register")); +} + +/* Callback for iterate_over_lwps. Mark that our local mirror of + LWP's debug registers has been changed, and cause LWP to stop if + it isn't already. Values are written from our local mirror to + the actual debug registers immediately prior to LWP resuming. */ + +static int +update_debug_registers_callback (struct lwp_info *lwp, void *arg) +{ + lwp_set_debug_registers_changed (lwp, 1); + + if (!lwp_is_stopped (lwp)) + linux_stop_lwp (lwp); + + /* Continue the iteration. */ + return 0; +} + +/* See nat/x86-linux-dregs.h. */ + +CORE_ADDR +x86_linux_dr_get_addr (int regnum) +{ + gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR); + + return x86_linux_dr_get (current_lwp_ptid (), regnum); +} + +/* See nat/x86-linux-dregs.h. */ + +void +x86_linux_dr_set_addr (int regnum, CORE_ADDR addr) +{ + ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (current_lwp_ptid ())); + + gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR); + + iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL); +} + +/* See nat/x86-linux-dregs.h. */ + +unsigned long +x86_linux_dr_get_control (void) +{ + return x86_linux_dr_get (current_lwp_ptid (), DR_CONTROL); +} + +/* See nat/x86-linux-dregs.h. */ + +void +x86_linux_dr_set_control (unsigned long control) +{ + ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (current_lwp_ptid ())); + + iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL); +} + +/* See nat/x86-linux-dregs.h. */ + +unsigned long +x86_linux_dr_get_status (void) +{ + return x86_linux_dr_get (current_lwp_ptid (), DR_STATUS); +} + +/* See nat/x86-linux-dregs.h. */ + +void +x86_linux_update_debug_registers (struct lwp_info *lwp) +{ + ptid_t ptid = ptid_of_lwp (lwp); + int clear_status = 0; + + gdb_assert (lwp_is_stopped (lwp)); + + if (lwp_debug_registers_changed (lwp)) + { + struct x86_debug_reg_state *state + = x86_debug_reg_state (ptid_get_pid (ptid)); + int i; + + /* Prior to Linux kernel 2.6.33 commit + 72f674d203cd230426437cdcf7dd6f681dad8b0d, setting DR0-3 to + a value that did not match what was enabled in DR_CONTROL + resulted in EINVAL. To avoid this we zero DR_CONTROL before + writing address registers, only writing DR_CONTROL's actual + value once all the addresses are in place. */ + x86_linux_dr_set (ptid, DR_CONTROL, 0); + + ALL_DEBUG_ADDRESS_REGISTERS (i) + if (state->dr_ref_count[i] > 0) + { + x86_linux_dr_set (ptid, i, state->dr_mirror[i]); + + /* If we're setting a watchpoint, any change the inferior + has made to its debug registers needs to be discarded + to avoid x86_stopped_data_address getting confused. */ + clear_status = 1; + } + + /* If DR_CONTROL is supposed to be zero then it's already set. */ + if (state->dr_control_mirror != 0) + x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror); + + lwp_set_debug_registers_changed (lwp, 0); + } + + if (clear_status + || lwp_stop_reason (lwp) == TARGET_STOPPED_BY_WATCHPOINT) + x86_linux_dr_set (ptid, DR_STATUS, 0); +} -- cgit v1.1