Re: [RFA 4/8] New port: TI C6x: Read loadmap from gdbserver

Yao Qi
2011-07-25T04:28:33Z

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On 07/22/2011 10:16 AM, Mike Frysinger wrote:

Mike, thanks for the review.

>> +#if defined __DSBT__
>> +static int
>
> rather than being tied to the exec format that *gdbserver* is being
> built as, shouldnt this be bound to the ptrace defines being available
> ? how abut using "#ifdef PTRACE_GETDSBT" ?
>

Yeah, that makes sense. Done.

>> +linux_read_loadmap (const char *annex, CORE_ADDR offset,
>> + unsigned char *myaddr, unsigned int len)
>
> indentation looks wrong wrt GNU style. needs tabs and spaces to
> properly align it.
>

Fixed.

>> + int addr = (strcmp (annex, "exec") == 0 ? (int) PTRACE_GETDSBT_EXEC :
>> + (strcmp (annex, "interp") == 0 ? (int) PTRACE_GETDSBT_INTERP :
>> + -1));
>> ...
>> + if (addr == -1)
>> + return -1;
>
> style with add init is off here too. but seems like it'd be cleaner
> to have this be a series of if statements incorporated into the -1
> check to make the -1 value unnecessary.
>

Agreed. Fixed.

>> + copy_length = actual_length - offset < len ? actual_length - offset : len;
>
> does gdb really not have min/max helpers ?
>

gdb has, but gdbserver doesn't. I'll leave the code here. A follow-up
patch can move min/max helper into common/ and use them in gdbserver.

>> + ptrace (PTRACE_GETDSBT, pid, addr, &data);
>
> what if it fails ?
>

We can return -1 if it fails. Done in new patch.

>> + {"fdpic", handle_qxfer_fdpic}
>
> style is broken. needs space after "{", space before "}", and comma after "}"
>

Fixed.

>> + /* Load maps for FDPIC systems. */
>> + TARGET_OBJECT_FDPIC
>
> i think this needs a trailing comma

Fixed.

--
Yao (é½å°§)

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2011-07-19 Andrew Stubbs <ams@codesourcery.com>
Yao Qi <yao@codesourcery.com>

gdb/
* remote.c (PACKET_qXfer_fdpic): New enum value.
(remote_protocol_features): Add qXfer:fdpic:read packet.
(remote_xfer_partial): Support TARGET_OBJECT_FDPIC.
(_initialize_remote): Add set/show remote read-fdpic-loadmap command.
* target.h (enum target_object): Add TARGET_OBJECT_FDPIC.

gdb/gdbserver:
* linux-low.c (struct target_loadseg): New type.
(struct target_loadmap): New type.
(linux_read_loadmap): New function.
(linux_target_ops): Add linux_read_loadmap.
* server.c (handle_query): Support qXfer:fdpic:read packet.
* target.h (struct target_ops): Add read_loadmap.

gdb/doc/
* gdb.texinfo : Document qXfer:fdpic:read packet.
---
gdb/doc/gdb.texinfo | 17 ++++++++++++
gdb/gdbserver/linux-low.c | 65 +++++++++++++++++++++++++++++++++++++++++++++
gdb/gdbserver/server.c | 19 +++++++++++++
gdb/gdbserver/target.h | 4 +++
gdb/remote.c | 10 +++++++
gdb/target.h | 2 +
6 files changed, 117 insertions(+), 0 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 129a46b..37c81b8 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -33654,6 +33654,10 @@ These are the currently defined stub features and their properties:
@tab @samp{-}
@tab Yes

+@item @samp{qXfer:fdpic:read}
+@tab No
+@tab @samp{-}
+@tab Yes

@item @samp{QNonStop}
@tab No
@@ -33765,6 +33769,10 @@ The remote stub understands the @samp{qXfer:threads:read} packet
The remote stub understands the @samp{qXfer:traceframe-info:read}
packet (@pxref{qXfer traceframe info read}).

+@item qXfer:fdpic:read
+The remote stub understands the @samp{qXfer:fdpic:read}
+packet (@pxref{qXfer fdpic loadmap read}).
+
@item QNonStop
The remote stub understands the @samp{QNonStop} packet
(@pxref{QNonStop}).
@@ -34020,6 +34028,15 @@ Return a description of the current traceframe's contents.
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).

+@item qXfer:fdpic:read:@var{annex}:@var{offset},@var{length}
+@anchor{qXfer fdpic loadmap read}
+Read contents of @code{loadmap}s on the target system. The
+annex, either @samp{exec} or @samp{interp}, specifies which @code{loadmap},
+executable @code{loadmap} or interpreter @code{loadmap} to read.
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+
@item qXfer:osdata:read::@var{offset},@var{length}
@anchor{qXfer osdata read}
Access the target's @dfn{operating system information}.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index d84fd68..f3641d0 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4964,6 +4964,66 @@ linux_core_of_thread (ptid_t ptid)
return core;
}

+#if defined __DSBT__
+struct target_loadseg
+{
+ /* Core address to which the segment is mapped. */
+ Elf32_Addr addr;
+ /* VMA recorded in the program header. */
+ Elf32_Addr p_vaddr;
+ /* Size of this segment in memory. */
+ Elf32_Word p_memsz;
+};
+
+struct target_loadmap
+{
+ /* Protocol version number, must be zero. */
+ Elf32_Word version;
+ /* Pointer to the DSBT table, its size, and the DSBT index. */
+ unsigned *dsbt_table;
+ unsigned dsbt_size, dsbt_index;
+ /* Number of segments in this map. */
+ Elf32_Word nsegs;
+ /* The actual memory map. */
+ struct target_loadseg segs[/*nsegs*/];
+};
+#endif
+
+#if defined PTRACE_GETDSBT
+static int
+linux_read_loadmap (const char *annex, CORE_ADDR offset,
+ unsigned char *myaddr, unsigned int len)
+{
+ int pid = lwpid_of (get_thread_lwp (current_inferior));
+ int addr = -1;
+ struct target_loadmap *data = NULL;
+ unsigned int actual_length, copy_length;
+
+ if (strcmp (annex, "exec") == 0)
+ addr= (int) PTRACE_GETDSBT_EXEC;
+ else if (strcmp (annex, "interp") == 0)
+ addr =(int) PTRACE_GETDSBT_INTERP;
+ else
+ return -1;
+
+ if (ptrace (PTRACE_GETDSBT, pid, addr, &data) != 0)
+ return -1;
+
+ if (data == NULL)
+ return -1;
+
+ actual_length = sizeof (struct target_loadmap)
+ + sizeof (struct target_loadseg) * data->nsegs;
+
+ if (offset < 0 || offset > actual_length)
+ return -1;
+
+ copy_length = actual_length - offset < len ? actual_length - offset : len;
+ memcpy (myaddr, ((char *)data) + offset, copy_length);
+ return copy_length;
+}
+#endif /* defined PTRACE_GETDSBT */
+
static void
linux_process_qsupported (const char *query)
{
@@ -5112,6 +5172,11 @@ static struct target_ops linux_target_ops = {
NULL,
#endif
linux_core_of_thread,
+#if defined PTRACE_GETDSBT
+ linux_read_loadmap,
+#else
+ NULL,
+#endif
linux_process_qsupported,
linux_supports_tracepoints,
linux_read_pc,
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index fd06c8f..7b19745 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1171,6 +1171,21 @@ handle_qxfer_traceframe_info (const char *annex,
return len;
}

+/* Handle qXfer:fdpic:read. */
+
+static int
+handle_qxfer_fdpic (const char *annex, gdb_byte *readbuf,
+ const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
+{
+ if (the_target->read_fdpic_loadmap == NULL)
+ return -2;
+
+ if (!target_running ())
+ return -1;
+
+ return (*the_target->read_fdpic_loadmap) (annex, offset, readbuf, len);
+}
+
static const struct qxfer qxfer_packets[] =
{
{ "auxv", handle_qxfer_auxv },
@@ -1182,6 +1197,7 @@ static const struct qxfer qxfer_packets[] =
{ "statictrace", handle_qxfer_statictrace },
{ "threads", handle_qxfer_threads },
{ "traceframe-info", handle_qxfer_traceframe_info },
+ { "fdpic", handle_qxfer_fdpic},
};

static int
@@ -1509,6 +1525,9 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
if (the_target->qxfer_siginfo != NULL)
strcat (own_buf, ";qXfer:siginfo:read+;qXfer:siginfo:write+");

+ if (the_target->read_fdpic_loadmap != NULL)
+ strcat (own_buf, ";qXfer:fdpic:read+");
+
/* We always report qXfer:features:read, as targets may
install XML files on a subsequent call to arch_setup.
If we reported to GDB on startup that we don't support
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 00214db..60f4f34 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -311,6 +311,10 @@ struct target_ops
/* Returns the core given a thread, or -1 if not known. */
int (*core_of_thread) (ptid_t);

+ /* Read FDPIC loadmaps. Read LEN bytes at OFFSET into a buffer at MYADDR. */
+ int (*read_fdpic_loadmap) (const char *annex, CORE_ADDR offset,
+ unsigned char *myaddr, unsigned int len);
+
/* Target specific qSupported support. */
void (*process_qsupported) (const char *);

diff --git a/gdb/remote.c b/gdb/remote.c
index b03ef59..9a1c653 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1262,6 +1262,7 @@ enum {
PACKET_bs,
PACKET_TracepointSource,
PACKET_QAllow,
+ PACKET_qXfer_fdpic,
PACKET_MAX
};

@@ -3769,6 +3770,8 @@ static struct protocol_feature remote_protocol_features[] = {
PACKET_QAllow },
{ "EnableDisableTracepoints", PACKET_DISABLE,
remote_enable_disable_tracepoint_feature, -1 },
+ { "qXfer:fdpic:read", PACKET_DISABLE, remote_supported_packet,
+ PACKET_qXfer_fdpic },
};

static char *remote_support_xml;
@@ -8299,6 +8302,10 @@ remote_xfer_partial (struct target_ops *ops, enum target_object object,
return remote_read_qxfer
(ops, "traceframe-info", annex, readbuf, offset, len,
&remote_protocol_packets[PACKET_qXfer_traceframe_info]);
+
+ case TARGET_OBJECT_FDPIC:
+ return remote_read_qxfer (ops, "fdpic", annex, readbuf, offset, len,
+ &remote_protocol_packets[PACKET_qXfer_fdpic]);
default:
return -1;
}
@@ -10903,6 +10910,9 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_statictrace_read],
"qXfer:statictrace:read", "read-sdata-object", 0);

+ add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_fdpic],
+ "qXfer:fdpic:read", "read-fdpic-loadmap", 0);
+
/* Keep the old ``set remote Z-packet ...'' working. Each individual
Z sub-packet has its own set and show commands, but users may
have sets to this variable in their .gdbinit files (or in their
diff --git a/gdb/target.h b/gdb/target.h
index 3b39d6f..e264657 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -274,6 +274,8 @@ enum target_object
TARGET_OBJECT_HPUX_SOLIB_GOT,
/* Traceframe info, in XML format. */
TARGET_OBJECT_TRACEFRAME_INFO,
+ /* Load maps for FDPIC systems. */
+ TARGET_OBJECT_FDPIC,
/* Possible future objects: TARGET_OBJECT_FILE, ... */
};

--
1.7.0.4