This is an automated email from Gerrit.
Tim Newsome (t...@sifive.com) just uploaded a new patch set to Gerrit, which
you can find at http://openocd.zylin.com/3803
-- gerrit
commit c1214c044a80f9d77a1762de66ebabd44a32435c
Author: Tim Newsome <t...@sifive.com>
Date: Wed Oct 5 07:57:38 2016 -0700
Perform small writes before sending OK.
To speed up downloads, OpenOCD sends gdb OK when a write is received,
even before the write has actually occurred. The failure is then
returned for the next write. That leads to the following confusing
behavior:
```
(gdb) p/x *((int*)0xdeadbeef)=8675309
$2 = 0x845fed
(gdb) p/x *((int*)0x80000000)=6874742
Cannot access memory at address 0x80000000
```
While it's actually the first write that failed.
This change hacks around this problem by not sending OK for small writes
(len<8) until the write has actually occurred. This does not impact
download speed, since during downloads (almost) all writes will have
much larger length.
Change-Id: I1f8b9bb19b0707487f840df6871e372e4ba228dd
Signed-off-by: Tim Newsome <t...@sifive.com>
diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c
index 4a18198..57c2f73 100644
--- a/src/server/gdb_server.c
+++ b/src/server/gdb_server.c
@@ -1473,6 +1473,10 @@ static int gdb_write_memory_binary_packet(struct
connection *connection,
uint32_t len = 0;
int retval = ERROR_OK;
+ /* Packets larger than fast_limit bytes will be acknowledged instantly
on
+ * the assumption that we're in a download and it's important to go as
fast
+ * as possible. */
+ uint32_t fast_limit = 8;
/* skip command character */
packet++;
@@ -1493,19 +1497,23 @@ static int gdb_write_memory_binary_packet(struct
connection *connection,
struct gdb_connection *gdb_connection = connection->priv;
- if (gdb_connection->mem_write_error) {
+ if (gdb_connection->mem_write_error)
retval = ERROR_FAIL;
- /* now that we have reported the memory write error, we can
clear the condition */
- gdb_connection->mem_write_error = false;
- }
- /* By replying the packet *immediately* GDB will send us a new packet
- * while we write the last one to the target.
- */
- if (retval == ERROR_OK)
- gdb_put_packet(connection, "OK", 2);
- else {
+ if (retval == ERROR_OK) {
+ if (len >= fast_limit) {
+ /* By replying the packet *immediately* GDB will send
us a new packet
+ * while we write the last one to the target.
+ * We only do this for larger writes, so that users who
do something like:
+ * p *((int*)0xdeadbeef)=8675309
+ * will get immediate feedback that that write failed.
+ */
+ gdb_put_packet(connection, "OK", 2);
+ }
+ } else {
retval = gdb_error(connection, retval);
+ /* now that we have reported the memory write error, we can
clear the condition */
+ gdb_connection->mem_write_error = false;
if (retval != ERROR_OK)
return retval;
}
@@ -1518,6 +1526,15 @@ static int gdb_write_memory_binary_packet(struct
connection *connection,
gdb_connection->mem_write_error = true;
}
+ if (len < fast_limit) {
+ if (retval != ERROR_OK) {
+ gdb_error(connection, retval);
+ gdb_connection->mem_write_error = false;
+ } else {
+ gdb_put_packet(connection, "OK", 2);
+ }
+ }
+
return ERROR_OK;
}
--
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