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Re: [patch v4 14/24] record-btrace: provide xfer_partial target method
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: Markus Metzger <markus dot t dot metzger at intel dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Sun, 18 Aug 2013 21:07:53 +0200
- Subject: Re: [patch v4 14/24] record-btrace: provide xfer_partial target method
- References: <1372842874-28951-1-git-send-email-markus dot t dot metzger at intel dot com> <1372842874-28951-15-git-send-email-markus dot t dot metzger at intel dot com>
On Wed, 03 Jul 2013 11:14:24 +0200, Markus Metzger wrote:
> Provide the xfer_partial target method for the btrace record target.
>
> Only allow memory accesses to readonly memory while we're replaying.
>
> 2013-07-03 Markus Metzger <markus.t.metzger@intel.com>
>
> * record-btrace.c (record_btrace_xfer_partial): New.
> (init_record_btrace_ops): Initialize xfer_partial.
>
>
> ---
> gdb/record-btrace.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 58 insertions(+), 0 deletions(-)
>
> diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
> index cb1f3bb..831a367 100644
> --- a/gdb/record-btrace.c
> +++ b/gdb/record-btrace.c
> @@ -754,6 +754,63 @@ record_btrace_is_replaying (void)
> return 0;
> }
>
> +/* The to_xfer_partial method of target record-btrace. */
> +
> +static LONGEST
> +record_btrace_xfer_partial (struct target_ops *ops, enum target_object object,
> + const char *annex, gdb_byte *readbuf,
> + const gdb_byte *writebuf, ULONGEST offset,
> + LONGEST len)
> +{
> + struct target_ops *t;
> +
> + /* Normalize the request so len is positive. */
> + if (len < 0)
> + {
> + offset += len;
> + len = - len;
> + }
I do not see LEN could be < 0, do you? Use just:
gdb_assetr (len >= 0);
(It even should never be LEN == 0 but that may not be guaranteed.)
> +
> + /* Filter out requests that don't make sense during replay. */
> + if (record_btrace_is_replaying ())
> + {
> + switch (object)
> + {
> + case TARGET_OBJECT_MEMORY:
> + case TARGET_OBJECT_RAW_MEMORY:
> + case TARGET_OBJECT_STACK_MEMORY:
> + {
> + /* We allow reading readonly memory. */
> + struct target_section *section;
> +
> + section = target_section_by_addr (ops, offset);
> + if (section != NULL)
> + {
> + /* Check if the section we found is readonly. */
> + if ((bfd_get_section_flags (section->bfd,
> + section->the_bfd_section)
> + & SEC_READONLY) != 0)
> + {
> + /* Truncate the request to fit into this section. */
> + len = min (len, section->endaddr - offset);
> + break;
> + }
> + }
> +
> + return -1;
> + }
> + }
> + }
> +
> + /* Forward the request. */
> + for (t = ops->beneath; t != NULL; t = t->beneath)
> + if (t->to_xfer_partial != NULL)
> + return t->to_xfer_partial (t, object, annex, readbuf, writebuf,
> + offset, len);
> +
> + return -1;
> +}
> +
> /* The to_fetch_registers method of target record-btrace. */
>
> static void
> @@ -936,6 +993,7 @@ init_record_btrace_ops (void)
> ops->to_call_history_from = record_btrace_call_history_from;
> ops->to_call_history_range = record_btrace_call_history_range;
> ops->to_record_is_replaying = record_btrace_is_replaying;
> + ops->to_xfer_partial = record_btrace_xfer_partial;
> ops->to_fetch_registers = record_btrace_fetch_registers;
> ops->to_store_registers = record_btrace_store_registers;
> ops->to_prepare_to_store = record_btrace_prepare_to_store;
> --
> 1.7.1