From: John Baldwin <jhb@FreeBSD.org>
To: gdb-patches@sourceware.org
Subject: [PATCH v2 06/12] x86-fbsd-nat: Copy debug register state on fork.
Date: Wed, 16 Mar 2022 13:19:17 -0700 [thread overview]
Message-ID: <20220316201923.89694-7-jhb@FreeBSD.org> (raw)
In-Reply-To: <20220316201923.89694-1-jhb@FreeBSD.org>
Use the FreeBSD native target low_new_fork hook to copy the
per-process debug state from the parent to the child on fork.
---
gdb/configure.nat | 4 ++--
gdb/x86-fbsd-nat.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
gdb/x86-fbsd-nat.h | 2 ++
3 files changed, 49 insertions(+), 2 deletions(-)
create mode 100644 gdb/x86-fbsd-nat.c
diff --git a/gdb/configure.nat b/gdb/configure.nat
index b45519fd116..92ad4a6522b 100644
--- a/gdb/configure.nat
+++ b/gdb/configure.nat
@@ -165,7 +165,7 @@ case ${gdb_host} in
i386)
# Host: FreeBSD/i386
NATDEPFILES="${NATDEPFILES} x86-nat.o nat/x86-dregs.o \
- x86-bsd-nat.o i386-fbsd-nat.o bsd-kvm.o"
+ x86-bsd-nat.o x86-fbsd-nat.o i386-fbsd-nat.o bsd-kvm.o"
;;
mips)
# Host: FreeBSD/mips
@@ -194,7 +194,7 @@ case ${gdb_host} in
# Host: FreeBSD/amd64
NATDEPFILES="${NATDEPFILES} amd64-nat.o \
amd64-fbsd-nat.o bsd-kvm.o x86-nat.o nat/x86-dregs.o \
- x86-bsd-nat.o"
+ x86-bsd-nat.o x86-fbsd-nat.o"
;;
esac
;;
diff --git a/gdb/x86-fbsd-nat.c b/gdb/x86-fbsd-nat.c
new file mode 100644
index 00000000000..ad8c693b68e
--- /dev/null
+++ b/gdb/x86-fbsd-nat.c
@@ -0,0 +1,45 @@
+/* Native-dependent code for FreeBSD x86.
+
+ Copyright (C) 2022 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 "x86-fbsd-nat.h"
+
+/* Implement the virtual fbsd_nat_target::low_new_fork method. */
+
+void
+x86_fbsd_nat_target::low_new_fork (ptid_t parent, pid_t child)
+{
+ struct x86_debug_reg_state *parent_state, *child_state;
+
+ /* If there is no parent state, no watchpoints nor breakpoints have
+ been set, so there is nothing to do. */
+ parent_state = x86_lookup_debug_reg_state (parent.pid ());
+ if (parent_state == nullptr)
+ return;
+
+ /* The kernel clears debug registers in the new child process after
+ fork, but 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. */
+
+ child_state = x86_debug_reg_state (child);
+ *child_state = *parent_state;
+}
diff --git a/gdb/x86-fbsd-nat.h b/gdb/x86-fbsd-nat.h
index f9d3514aab4..cdb8cd36a4c 100644
--- a/gdb/x86-fbsd-nat.h
+++ b/gdb/x86-fbsd-nat.h
@@ -29,6 +29,8 @@ class x86_fbsd_nat_target : public x86bsd_nat_target<fbsd_nat_target>
{
bool supports_stopped_by_hw_breakpoint () override
{ return true; }
+
+ void low_new_fork (ptid_t parent, pid_t child) override;
};
#endif /* x86-bsd-nat.h */
--
2.34.1
next prev parent reply other threads:[~2022-03-16 20:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-16 20:19 [PATCH v2 00/12] FreeBSD/aarch64 hardware watchpoint support John Baldwin
2022-03-16 20:19 ` [PATCH v2 01/12] Remove USE_SIGTRAP_SIGINFO condition for FreeBSD/x86 debug regs support John Baldwin
2022-03-16 20:19 ` [PATCH v2 02/12] x86-nat: Use an unordered_map to store per-pid debug reg state John Baldwin
2022-03-21 18:07 ` Pedro Alves
2022-03-16 20:19 ` [PATCH v2 03/12] x86-nat: Add x86_lookup_debug_reg_state John Baldwin
2022-03-21 18:10 ` Pedro Alves
2022-03-16 20:19 ` [PATCH v2 04/12] Add an x86_fbsd_nat_target mixin class for FreeBSD x86 native targets John Baldwin
2022-03-16 20:19 ` [PATCH v2 05/12] fbsd-nat: Add a low_new_fork virtual method John Baldwin
2022-03-16 20:19 ` John Baldwin [this message]
2022-03-16 20:19 ` [PATCH v2 07/12] nat: Split out platform-independent aarch64 debug register support John Baldwin
2022-03-17 15:37 ` Luis Machado
2022-03-16 20:19 ` [PATCH v2 08/12] aarch64: Add an aarch64_nat_target mixin class John Baldwin
2022-03-17 15:35 ` Luis Machado
2022-03-16 20:19 ` [PATCH v2 09/12] fbsd-nat: Add helper routine to fetch siginfo_t for a ptid John Baldwin
2022-03-16 20:19 ` [PATCH v2 10/12] fbsd-nat: Add a low_delete_thread virtual method John Baldwin
2022-03-16 20:19 ` [PATCH v2 11/12] fbsd-nat: Add a low_prepare_to_resume " John Baldwin
2022-03-16 20:19 ` [PATCH v2 12/12] Add support for hardware breakpoints/watchpoints on FreeBSD/Aarch64 John Baldwin
2022-03-30 15:23 ` [PATCH v2 00/12] FreeBSD/aarch64 hardware watchpoint support Luis Machado
2022-03-30 15:31 ` Luis Machado
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