[PING] [PATCH] Enable hardware watchpoints on attach for aarch64
Alan Hayward
Alan.Hayward@arm.com
Thu Jun 7 13:19:00 GMT 2018
Aarch64 changes look good to me.
I’m not up to speed enough with .exp files to comment on that part.
I tested it on an aarch64 box, and it works fine for me.
Alan.
> On 7 Jun 2018, at 09:54, Richard Bunt <richard.bunt@arm.com> wrote:
>
> Polite ping.
>
>
> On 05/23/2018 09:48 AM, Richard Bunt wrote:
>> This patch fixes a bug whereby hardware watchpoints are not used on
>> aarch64 when attaching to a target. The fix adds an aarch64 specialization
>> of post_attach which records the number of available hardware debug registers
>> using aarch64_linux_get_debug_reg_capacity. This implementation mirrors that
>> of aarch64_linux_child_post_startup_inferior which successfully enables the
>> use of hardware watchpoints when launching the target under the debugger.
>>
>> 2018-05-14 Richard Bunt<richard.bunt@arm.com>
>> Dirk Schubert<dirk.schubert@arm.com>
>>
>> * aarch64-linux-nat.c (post_attach): New.
>> (aarch64_linux_nat_target::post_attach): Override post_attach to
>> record the number of hardware debug registers.
>>
>> gdb/testsuite/ChangeLog:
>>
>> 2018-05-14 Richard Bunt<richard.bunt@arm.com>
>>
>> * gdb.base/watchpoint-hw-attach.c: New test.
>> * gdb.base/watchpoint-hw-attach.exp: New file.
>> ---
>> Annotation for this patch
>> gdb/aarch64-linux-nat.c | 18 ++++++
>> gdb/testsuite/gdb.base/watchpoint-hw-attach.c | 44 +++++++++++++
>> gdb/testsuite/gdb.base/watchpoint-hw-attach.exp | 85 +++++++++++++++++++++++++
>> 3 files changed, 147 insertions(+)
>> create mode 100644 gdb/testsuite/gdb.base/watchpoint-hw-attach.c
>> create mode 100644 gdb/testsuite/gdb.base/watchpoint-hw-attach.exp
>>
>> diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
>> index 908b83a..e0f75d0 100644
>> --- a/gdb/aarch64-linux-nat.c
>> +++ b/gdb/aarch64-linux-nat.c
>> @@ -76,6 +76,9 @@ public:
>> /* Override the GNU/Linux inferior startup hook. */
>> void post_startup_inferior (ptid_t) override;
>>
>> + /* Override the GNU/Linux post attach hook. */
>> + void post_attach (int pid) override;
>> +
>> /* These three defer to common nat/ code. */
>> void low_new_thread (struct lwp_info *lp) override
>> { aarch64_linux_new_thread (lp); }
>> @@ -521,6 +524,21 @@ aarch64_linux_nat_target::post_startup_inferior (ptid_t ptid)
>> linux_nat_target::post_startup_inferior (ptid);
>> }
>>
>> +/* Implement the "post_attach" target_ops method. */
>> +
>> +void
>> +aarch64_linux_nat_target::post_attach (int pid)
>> +{
>> + low_forget_process (pid);
>> + /* Set the hardware debug register capacity. If
>> + aarch64_linux_get_debug_reg_capacity is not called
>> + (as it is in aarch64_linux_child_post_startup_inferior) then
>> + software watchpoints will be used instead of hardware
>> + watchpoints when attaching to a target. */
>> + aarch64_linux_get_debug_reg_capacity (pid);
>> + linux_nat_target::post_attach (pid);
>> +}
>> +
>> extern struct target_desc *tdesc_arm_with_neon;
>>
>> /* Implement the "read_description" target_ops method. */
>> diff --git a/gdb/testsuite/gdb.base/watchpoint-hw-attach.c b/gdb/testsuite/gdb.base/watchpoint-hw-attach.c
>> new file mode 100644
>> index 0000000..9d55b28
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/watchpoint-hw-attach.c
>> @@ -0,0 +1,44 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> + Copyright 2018 Free Software Foundation, Inc.
>> +
>> + 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 <stdio.h>
>> +#include <sys/types.h>
>> +#include <unistd.h>
>> +
>> +/* This is set to 1 by the debugger post attach to continue to the
>> + watchpoint trigger. */
>> +volatile int should_continue = 0;
>> +/* The variable to place a watchpoint on. */
>> +volatile int watched_variable = 0;
>> +
>> +int
>> +main (void)
>> +{
>> + unsigned int counter = 1;
>> + int mypid = getpid ();
>> +
>> + /* Wait for the debugger to attach, but not indefinitely so this
>> + test program is not left hanging around. */
>> + for (counter = 0; !should_continue && counter < 100; counter++)
>> + sleep (1); /* pidacquired */
>> +
>> + watched_variable = 0; /* prewatchtrigger */
>> + /* Trigger a watchpoint. */
>> + watched_variable = 4;
>> + printf ("My variable is %d\n", watched_variable);
>> + return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.base/watchpoint-hw-attach.exp b/gdb/testsuite/gdb.base/watchpoint-hw-attach.exp
>> new file mode 100644
>> index 0000000..a030cb7
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/watchpoint-hw-attach.exp
>> @@ -0,0 +1,85 @@
>> +# Copyright 2018 Free Software Foundation, Inc.
>> +
>> +# 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/>.
>> +
>> +# watchpoint-hw-attach.exp -- Test if hardware watchpoints are used
>> +# when attaching to a target.
>> +
>> +if {[skip_hw_watchpoint_tests]} {
>> + return 0
>> +}
>> +
>> +if {![can_spawn_for_attach]} {
>> + return 0
>> +}
>> +
>> +standard_testfile
>> +
>> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
>> + return -1
>> +}
>> +
>> +clean_restart $binfile
>> +
>> +if ![runto_main] {
>> + untested "can't run to main"
>> + return -1
>> +}
>> +# Run to the point where mypid in the test program has been
>> +# populated.
>> +gdb_breakpoint [gdb_get_line_number "pidacquired"]
>> +gdb_continue_to_breakpoint "pidacquired"
>> +
>> +# Get the PID of the test process.
>> +set testpid ""
>> +set test "get inferior process ID"
>> + gdb_test_multiple "p mypid" $test {
>> + -re " = ($decimal)\r\n$gdb_prompt $" {
>> + set testpid $expect_out(1,string)
>> + pass $test
>> + }
>> +}
>> +
>> +gdb_test "detach" "Detaching from program: .*"
>> +
>> +if {$testpid == ""} {
>> + return -1
>> +}
>> +
>> +# A clean restart is needed to force the hardware watchpoint setup
>> +# logic to run post attach rather than post inferior launch.
>> +clean_restart $binfile
>> +
>> +set test "attach $testpid"
>> +gdb_test_multiple $test $test {
>> + -re "Attaching to program.*process $testpid\r\n.*$gdb_prompt $" {
>> + pass "$test"
>> + }
>> + timeout {
>> + fail "$test"
>> + }
>> +}
>> +
>> +gdb_test_no_output "set should_continue = 1"
>> +# Ensure the test program is in the top frame so the required
>> +# variables are in scope.
>> +gdb_breakpoint [gdb_get_line_number "prewatchtrigger"]
>> +gdb_continue_to_breakpoint "prewatchtrigger"
>> +
>> +gdb_test "watch watched_variable" \
>> + "Hardware watchpoint $decimal: watched_variable"
>> +
>> +gdb_test "continue" \
>> + "continue.*Continuing.*\.Hardware watchpoint $decimal:\
>> + watched_variable.*Old value = 0.*New value = 4.*"
>> -- 1.8.5.6
>>
>
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