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rtos/hwthread: add hardware-thread pseudo rtos 

This patch adds "hwthread", a pseudo rtos that represents cpu cores
in an SMP system as threads to gdb. This allows to debug SMP
system kernels in a more sensible manner and removes the current
atrocities of switching gdb manually between CPU cores to update
the context.

Change-Id: Ib781c6c34097689d21d9e02011e4d74a4a742379
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>

Source: http://openocd.zylin.com/#/c/3999
This commit is contained in:
Matthias Welwarsky 2017-02-17 16:16:51 +01:00 committed by Tim Newsome
parent afb450af6f
commit a01b079440
4 changed files with 464 additions and 51 deletions
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118
doc/openocd.texi
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@ -9858,55 +9858,6 @@ and GDB would require stopping the target to get the prompt back.
Do not use this mode under an IDE like Eclipse as it caches values of
previously shown varibles.
@anchor{usingopenocdsmpwithgdb}
@section Using OpenOCD SMP with GDB
@cindex SMP
For SMP support following GDB serial protocol packet have been defined :
@itemize @bullet
@item j - smp status request
@item J - smp set request
@end itemize
OpenOCD implements :
@itemize @bullet
@item @option{jc} packet for reading core id displayed by
GDB connection. Reply is @option{XXXXXXXX} (8 hex digits giving core id) or
@option{E01} for target not smp.
@item @option{JcXXXXXXXX} (8 hex digits) packet for setting core id displayed at next GDB continue
(core id -1 is reserved for returning to normal resume mode). Reply @option{E01}
for target not smp or @option{OK} on success.
@end itemize
Handling of this packet within GDB can be done :
@itemize @bullet
@item by the creation of an internal variable (i.e @option{_core}) by mean
of function allocate_computed_value allowing following GDB command.
@example
set $_core 1
#Jc01 packet is sent
print $_core
#jc packet is sent and result is affected in $
@end example
@item by the usage of GDB maintenance command as described in following example (2 cpus in SMP with
core id 0 and 1 @pxref{definecputargetsworkinginsmp,,Define CPU targets working in SMP}).
@example
# toggle0 : force display of coreid 0
define toggle0
maint packet Jc0
continue
main packet Jc-1
end
# toggle1 : force display of coreid 1
define toggle1
maint packet Jc1
continue
main packet Jc-1
end
@end example
@end itemize
@section RTOS Support
@cindex RTOS Support
@anchor{gdbrtossupport}
@ -9937,12 +9888,11 @@ Currently supported rtos's include:
@item @option{mqx}
@item @option{uCOS-III}
@item @option{nuttx}
@item @option{hwthread} (This is not an actual RTOS. @xref{usingopenocdsmpwithgdb,,Using OpenOCD SMP with GDB}.)
@end itemize
@quotation Note
Before an RTOS can be detected, it must export certain symbols; otherwise, it cannot
be used by OpenOCD. Below is a list of the required symbols for each supported RTOS.
@end quotation
@table @code
@item eCos symbols
@ -9989,6 +9939,72 @@ contrib/rtos-helpers/FreeRTOS-openocd.c
contrib/rtos-helpers/uCOS-III-openocd.c
@end table
@anchor{usingopenocdsmpwithgdb}
@section Using OpenOCD SMP with GDB
@cindex SMP
@cindex RTOS
@cindex hwthread
OpenOCD includes a pseudo RTOS called @emph{hwthread} that presents CPU cores
("hardware threads") in an SMP system as threads to GDB. With this extension,
GDB can be used to inspect the state of an SMP system in a natural way.
After halting the system, using the GDB command @command{info threads} will
list the context of each active CPU core in the system. GDB's @command{thread}
command can be used to switch the view to a different CPU core.
The @command{step} and @command{stepi} commands can be used to step a specific core
while other cores are free-running or remain halted, depending on the
scheduler-locking mode configured in GDB.
@section Legacy SMP core switching support
@quotation Note
This method is deprecated in favor of the @emph{hwthread} pseudo RTOS.
@end quotation
For SMP support following GDB serial protocol packet have been defined :
@itemize @bullet
@item j - smp status request
@item J - smp set request
@end itemize
OpenOCD implements :
@itemize @bullet
@item @option{jc} packet for reading core id displayed by
GDB connection. Reply is @option{XXXXXXXX} (8 hex digits giving core id) or
@option{E01} for target not smp.
@item @option{JcXXXXXXXX} (8 hex digits) packet for setting core id displayed at next GDB continue
(core id -1 is reserved for returning to normal resume mode). Reply @option{E01}
for target not smp or @option{OK} on success.
@end itemize
Handling of this packet within GDB can be done :
@itemize @bullet
@item by the creation of an internal variable (i.e @option{_core}) by mean
of function allocate_computed_value allowing following GDB command.
@example
set $_core 1
#Jc01 packet is sent
print $_core
#jc packet is sent and result is affected in $
@end example
@item by the usage of GDB maintenance command as described in following example (2 cpus in SMP with
core id 0 and 1 @pxref{definecputargetsworkinginsmp,,Define CPU targets working in SMP}).
@example
# toggle0 : force display of coreid 0
define toggle0
maint packet Jc0
continue
main packet Jc-1
end
# toggle1 : force display of coreid 1
define toggle1
maint packet Jc1
continue
main packet Jc-1
end
@end example
@end itemize
@node Tcl Scripting API
@chapter Tcl Scripting API
@cindex Tcl Scripting API

1
src/rtos/Makefile.am
View File

@ -17,6 +17,7 @@ noinst_LTLIBRARIES += %D%/librtos.la
%D%/riscv_debug.c \
%D%/uCOS-III.c \
%D%/nuttx.c \
%D%/hwthread.c \
%D%/rtos.h \
%D%/rtos_standard_stackings.h \
%D%/rtos_ecos_stackings.h \

394
src/rtos/hwthread.c Normal file
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@ -0,0 +1,394 @@
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <helper/time_support.h>
#include <jtag/jtag.h>
#include "target/target.h"
#include "target/target_type.h"
#include "target/register.h"
#include "rtos.h"
#include "helper/log.h"
#include "helper/types.h"
#include "server/gdb_server.h"
static bool hwthread_detect_rtos(struct target *target);
static int hwthread_create(struct target *target);
static int hwthread_update_threads(struct rtos *rtos);
static int hwthread_get_thread_reg_list(struct rtos *rtos, int64_t thread_id, char **hex_reg_list);
static int hwthread_get_symbol_list_to_lookup(symbol_table_elem_t *symbol_list[]);
static int hwthread_smp_init(struct target *target);
#define HW_THREAD_NAME_STR_SIZE (32)
extern int rtos_thread_packet(struct connection *connection, const char *packet, int packet_size);
static inline threadid_t threadid_from_target(const struct target *target)
{
return target->coreid + 1;
}
const struct rtos_type hwthread_rtos = {
.name = "hwthread",
.detect_rtos = hwthread_detect_rtos,
.create = hwthread_create,
.update_threads = hwthread_update_threads,
.get_thread_reg_list = hwthread_get_thread_reg_list,
.get_symbol_list_to_lookup = hwthread_get_symbol_list_to_lookup,
.smp_init = hwthread_smp_init,
};
struct hwthread_params {
int dummy_param;
};
static int hwthread_fill_thread(struct rtos *rtos, struct target *curr, int thread_num)
{
char tmp_str[HW_THREAD_NAME_STR_SIZE];
threadid_t tid = threadid_from_target(curr);
memset(tmp_str, 0, HW_THREAD_NAME_STR_SIZE);
/* thread-id is the core-id of this core inside the SMP group plus 1 */
rtos->thread_details[thread_num].threadid = tid;
/* create the thread name */
rtos->thread_details[thread_num].exists = true;
rtos->thread_details[thread_num].thread_name_str = strdup(target_name(curr));
snprintf(tmp_str, HW_THREAD_NAME_STR_SIZE-1, "state: %s", debug_reason_name(curr));
rtos->thread_details[thread_num].extra_info_str = strdup(tmp_str);
return ERROR_OK;
}
static int hwthread_update_threads(struct rtos *rtos)
{
int threads_found = 0;
int thread_list_size = 0;
struct target_list *head;
struct target *target;
int64_t current_thread = 0;
enum target_debug_reason current_reason = DBG_REASON_UNDEFINED;
if (rtos == NULL)
return -1;
target = rtos->target;
/* wipe out previous thread details if any */
rtos_free_threadlist(rtos);
/* determine the number of "threads" */
if (target->smp) {
for (head = target->head; head != NULL; head = head->next) {
struct target *curr = head->target;
if (!target_was_examined(curr))
continue;
++thread_list_size;
}
} else
thread_list_size = 1;
/* create space for new thread details */
rtos->thread_details = malloc(sizeof(struct thread_detail) * thread_list_size);
if (target->smp) {
/* loop over all threads */
for (head = target->head; head != NULL; head = head->next) {
struct target *curr = head->target;
if (!target_was_examined(curr))
continue;
threadid_t tid = threadid_from_target(curr);
hwthread_fill_thread(rtos, curr, threads_found);
/* find an interesting thread to set as current */
switch (current_reason) {
case DBG_REASON_UNDEFINED:
current_reason = curr->debug_reason;
current_thread = tid;
break;
case DBG_REASON_SINGLESTEP:
/* single-step can only be overridden by itself */
if (curr->debug_reason == DBG_REASON_SINGLESTEP) {
if (tid == rtos->current_threadid)
current_thread = tid;
}
break;
case DBG_REASON_BREAKPOINT:
/* single-step overrides breakpoint */
if (curr->debug_reason == DBG_REASON_SINGLESTEP) {
current_reason = curr->debug_reason;
current_thread = tid;
} else
/* multiple breakpoints, prefer gdbs' threadid */
if (curr->debug_reason == DBG_REASON_BREAKPOINT) {
if (tid == rtos->current_threadid)
current_thread = tid;
}
break;
case DBG_REASON_WATCHPOINT:
/* breakpoint and single-step override watchpoint */
if (curr->debug_reason == DBG_REASON_SINGLESTEP ||
curr->debug_reason == DBG_REASON_BREAKPOINT) {
current_reason = curr->debug_reason;
current_thread = tid;
}
break;
case DBG_REASON_DBGRQ:
/* all other reasons override debug-request */
if (curr->debug_reason == DBG_REASON_SINGLESTEP ||
curr->debug_reason == DBG_REASON_WATCHPOINT ||
curr->debug_reason == DBG_REASON_BREAKPOINT) {
current_reason = curr->debug_reason;
current_thread = tid;
} else
if (curr->debug_reason == DBG_REASON_DBGRQ) {
if (tid == rtos->current_threadid)
current_thread = tid;
}
break;
default:
break;
}
threads_found++;
}
} else {
hwthread_fill_thread(rtos, target, threads_found);
current_thread = threadid_from_target(target);
threads_found++;
}
rtos->thread_count = threads_found;
/* we found an interesting thread, set it as current */
if (current_thread != 0)
rtos->current_thread = current_thread;
else if (rtos->current_threadid != 0)
rtos->current_thread = rtos->current_threadid;
else
rtos->current_thread = threadid_from_target(target);
LOG_DEBUG("%s current_thread=%i", __func__, (int)rtos->current_thread);
return 0;
}
static int hwthread_smp_init(struct target *target)
{
return hwthread_update_threads(target->rtos);
}
static inline int gdb_reg_pos(struct target *target, int pos, int len)
{
if (target->endianness == TARGET_LITTLE_ENDIAN)
return pos;
else
return len - 1 - pos;
}
/* Convert register to string of bytes. NB! The # of bits in the
* register might be non-divisible by 8(a byte), in which
* case an entire byte is shown.
*
* NB! the format on the wire is the target endianness
*
* The format of reg->value is little endian
*
*/
static void gdb_str_to_target(struct target *target,
char *tstr, struct reg *reg)
{
int i;
uint8_t *buf;
int buf_len;
buf = reg->value;
buf_len = DIV_ROUND_UP(reg->size, 8);
for (i = 0; i < buf_len; i++) {
int j = gdb_reg_pos(target, i, buf_len);
tstr += sprintf(tstr, "%02x", buf[j]);
}
}
static int hwthread_get_thread_reg_list(struct rtos *rtos, int64_t thread_id, char **hex_reg_list)
{
struct target_list *head;
struct target *target;
struct target *curr;
struct reg **reg_list;
int reg_list_size;
int reg_packet_size = 0;
char *reg_packet;
char *reg_packet_p;
int i;
int retval;
*hex_reg_list = NULL;
if (rtos == NULL)
return ERROR_FAIL;
target = rtos->target;
/* Find the thread with that thread_id */
if (target->smp) {
curr = NULL;
for (head = target->head; head != NULL; head = head->next) {
curr = head->target;
if (thread_id == threadid_from_target(curr))
break;
}
if (head == NULL)
return ERROR_FAIL;
} else {
curr = target;
if (thread_id != threadid_from_target(curr))
return ERROR_FAIL;
}
if (!target_was_examined(curr))
return ERROR_FAIL;
retval = target_get_gdb_reg_list(curr, &reg_list, &reg_list_size,
REG_CLASS_GENERAL);
if (retval != ERROR_OK)
return retval;
for (i = 0; i < reg_list_size; i++)
reg_packet_size += DIV_ROUND_UP(reg_list[i]->size, 8) * 2;
if (reg_packet_size == 0)
return ERROR_FAIL;
reg_packet = malloc(reg_packet_size + 1); /* plus one for string termination null */
if (reg_packet == NULL)
return ERROR_FAIL;
reg_packet_p = reg_packet;
for (i = 0; i < reg_list_size; i++) {
if (!reg_list[i]->valid)
reg_list[i]->type->get(reg_list[i]);
gdb_str_to_target(target, reg_packet_p, reg_list[i]);
reg_packet_p += DIV_ROUND_UP(reg_list[i]->size, 8) * 2;
}
*hex_reg_list = reg_packet;
free(reg_list);
return ERROR_OK;
}
static int hwthread_get_symbol_list_to_lookup(symbol_table_elem_t *symbol_list[])
{
/* return an empty list, we don't have any symbols to look up */
*symbol_list = calloc(1, sizeof(symbol_table_elem_t));
(*symbol_list)[0].symbol_name = NULL;
return 0;
}
static int hwthread_target_for_threadid(struct connection *connection, int64_t thread_id, struct target **p_target)
{
struct target *target = get_target_from_connection(connection);
struct target_list *head;
struct target *curr;
if (target->smp) {
/* Find the thread with that thread_id */
curr = NULL;
for (head = target->head; head != NULL; head = head->next) {
curr = head->target;
if (thread_id == threadid_from_target(curr))
break;
}
if (head == NULL)
return ERROR_FAIL;
} else {
curr = target;
if (thread_id != threadid_from_target(curr))
return ERROR_FAIL;
}
*p_target = curr;
return ERROR_OK;
}
static bool hwthread_detect_rtos(struct target *target)
{
/* always return 0, avoid auto-detection */
return false;
}
static int hwthread_thread_packet(struct connection *connection, const char *packet, int packet_size)
{
struct target *target = get_target_from_connection(connection);
struct target *curr = NULL;
int64_t current_threadid;
if (packet[0] == 'H' && packet[1] == 'g') {
sscanf(packet, "Hg%16" SCNx64, &current_threadid);
if (current_threadid > 0) {
if (hwthread_target_for_threadid(connection, current_threadid, &curr) != ERROR_OK) {
LOG_ERROR("hwthread: cannot find thread id %"PRId64, current_threadid);
gdb_put_packet(connection, "E01", 3);
return ERROR_FAIL;
}
target->rtos->current_thread = current_threadid;
} else
if (current_threadid == 0 || current_threadid == -1)
target->rtos->current_thread = threadid_from_target(target);
target->rtos->current_threadid = current_threadid;
gdb_put_packet(connection, "OK", 2);
return ERROR_OK;
}
return rtos_thread_packet(connection, packet, packet_size);
}
static int hwthread_create(struct target *target)
{
LOG_INFO("Hardware thread awareness created");
target->rtos->rtos_specific_params = NULL;
target->rtos->current_thread = 0;
target->rtos->thread_details = NULL;
target->rtos->gdb_target_for_threadid = hwthread_target_for_threadid;
target->rtos->gdb_thread_packet = hwthread_thread_packet;
return 0;
}

2
src/rtos/rtos.c
View File

@ -36,6 +36,7 @@ extern struct rtos_type embKernel_rtos;
extern struct rtos_type mqx_rtos;
extern struct rtos_type uCOS_III_rtos;
extern struct rtos_type nuttx_rtos;
extern struct rtos_type hwthread_rtos;
extern struct rtos_type riscv_rtos;
static struct rtos_type *rtos_types[] = {
@ -48,6 +49,7 @@ static struct rtos_type *rtos_types[] = {
&mqx_rtos,
&uCOS_III_rtos,
&nuttx_rtos,
&hwthread_rtos,
&riscv_rtos,
NULL
};