From: Luis Machado <luis.machado@linaro.org>
To: gdb-patches@sourceware.org
Subject: [PING][PATCH] Fix displaced stepping watchpoint check order
Date: Thu, 1 Jul 2021 10:53:54 -0300 [thread overview]
Message-ID: <0805224e-dbb1-b5b4-f686-1efb85d135ed@linaro.org> (raw)
In-Reply-To: <20210608154230.354202-1-luis.machado@linaro.org>
On 6/8/21 12:42 PM, Luis Machado wrote:
> When checking the stopped data address, I noticed, under some circumstances,
> that the instruction at PC wasn't the expected one. This happens because the
> displaced stepping machinery restores the buffer before checking if the
> instruction executed successfully, which in turn calls the watchpoint check.
>
> I guess this was never noticed because stopped data address checks usually
> don't need to fetch the instruction at PC, but AArch64 needs to do it from
> now on.
>
> We should check if the instruction executed successfully before we restore the
> scratchpad contents.
>
> Regression tested on aarch64-linux/Ubuntu 20.04.
>
> gdb/ChangeLog:
>
> YYYY-MM-DD Luis Machado <luis.machado@linaro.org>
>
> * displaced-stepping.c (displaced_step_buffers::finish): Move check
> upwards.
> ---
> gdb/displaced-stepping.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/displaced-stepping.c b/gdb/displaced-stepping.c
> index 59b78c22f6a..06324d523d8 100644
> --- a/gdb/displaced-stepping.c
> +++ b/gdb/displaced-stepping.c
> @@ -227,6 +227,11 @@ displaced_step_buffers::finish (gdbarch *arch, thread_info *thread,
>
> ULONGEST len = gdbarch_max_insn_length (arch);
>
> + /* Check if the execution was successful before restoring the buffer
> + contents. */
> + bool instruction_executed_successfully
> + = displaced_step_instruction_executed_successfully (arch, sig);
> +
> /* Restore memory of the buffer. */
> write_memory_ptid (thread->ptid, buffer->addr,
> buffer->saved_copy.data (), len);
> @@ -237,9 +242,6 @@ displaced_step_buffers::finish (gdbarch *arch, thread_info *thread,
>
> regcache *rc = get_thread_regcache (thread);
>
> - bool instruction_executed_successfully
> - = displaced_step_instruction_executed_successfully (arch, sig);
> -
> if (instruction_executed_successfully)
> {
> gdbarch_displaced_step_fixup (arch, copy_insn_closure.get (),
>
next prev parent reply other threads:[~2021-07-01 13:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-08 15:42 [PATCH] " Luis Machado
2021-06-15 14:09 ` [Ping][PATCH] " Luis Machado
2021-06-22 1:56 ` [PING] [PATCH] " Luis Machado
2021-07-01 13:53 ` Luis Machado [this message]
2021-07-23 13:25 ` [PING][PATCH] " Luis Machado
2021-07-29 19:36 ` [PATCH] " Simon Marchi
2021-07-29 20:17 ` Luis Machado
2021-07-30 0:59 ` Simon Marchi
2021-07-30 1:32 ` Luis Machado
2021-08-19 1:31 ` Simon Marchi
2021-08-19 16:13 ` Luis Machado
2021-08-19 18:23 ` Simon Marchi
2021-08-19 18:48 ` Luis Machado
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