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server: gdb: respect command gdb_report_register_access_error 

Commit 236c54c94a ("server/gdb_server.c: support unavailable
registers") correctly returns a string of 'x' when the register is
not available in the current target.

While implementing this, it incorrectly drops the pre-existing
feature of optionally ignoring errors while reading a register.
This feature has a real use case documented in the OpenOCD manual
in chapter 'Using GDB as a non-intrusive memory inspector', where
GDB attaches to a target without halting it. For targets that need
to be halted to read its registers, we need to hack the values of
the registers returned to GDB; either returning 'xxxx' or an error
causes GDB to drop the connection.

Re-add the check on 'gdb_report_register_access_error' to keep the
pre-existing behavior when a register error has to be ignored:
- return a string of '0';
- drop a debug message.

Change-Id: Ie65c92f259f92502e688914f334655b635874179
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Fixes: 236c54c94a ("server/gdb_server.c: support unavailable registers")
Reviewed-on: https://review.openocd.org/c/openocd/+/8228
Tested-by: jenkins
This commit is contained in:
Antonio Borneo 2024-05-03 23:04:46 +02:00
parent 437dde701c
commit 71013521d7
1 changed files with 8 additions and 2 deletions
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10
src/server/gdb_server.c
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@ -1233,6 +1233,8 @@ static int gdb_get_reg_value_as_str(struct target *target, char *tstr, struct re
tstr[len] = '\0';
return ERROR_OK;
}
memset(tstr, '0', len);
tstr[len] = '\0';
return ERROR_FAIL;
}
@ -1277,7 +1279,9 @@ static int gdb_get_registers_packet(struct connection *connection,
for (i = 0; i < reg_list_size; i++) {
if (!reg_list[i] || reg_list[i]->exist == false || reg_list[i]->hidden)
continue;
if (gdb_get_reg_value_as_str(target, reg_packet_p, reg_list[i]) != ERROR_OK) {
retval = gdb_get_reg_value_as_str(target, reg_packet_p, reg_list[i]);
if (retval != ERROR_OK && gdb_report_register_access_error) {
LOG_DEBUG("Couldn't get register %s.", reg_list[i]->name);
free(reg_packet);
free(reg_list);
return gdb_error(connection, retval);
@ -1395,7 +1399,9 @@ static int gdb_get_register_packet(struct connection *connection,
reg_packet = calloc(DIV_ROUND_UP(reg_list[reg_num]->size, 8) * 2 + 1, 1); /* plus one for string termination null */
if (gdb_get_reg_value_as_str(target, reg_packet, reg_list[reg_num]) != ERROR_OK) {
retval = gdb_get_reg_value_as_str(target, reg_packet, reg_list[reg_num]);
if (retval != ERROR_OK && gdb_report_register_access_error) {
LOG_DEBUG("Couldn't get register %s.", reg_list[reg_num]->name);
free(reg_packet);
free(reg_list);
return gdb_error(connection, retval);