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Fix dead loop after an unexpected unplug #913

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merged 1 commit into from
Apr 8, 2020
Merged

Fix dead loop after an unexpected unplug #913

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222 changes: 167 additions & 55 deletions src/gdbserver/gdb-server.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1115,8 +1115,13 @@ int serve(stlink_t *sl, st_state_t *st) {
* emulate attaching and detaching to target.
*/
unsigned int attached = 1;

/*
* If a critical error is detected, break from the loop
*/
int critical_error = 0;
int ret;
while(1) {
ret = 0;
char* packet;

int status = gdb_recv_packet(client, &packet);
Expand Down Expand Up @@ -1226,32 +1231,75 @@ int serve(stlink_t *sl, st_state_t *st) {
if (!strncmp(cmd, "resume", 6)) {// resume
DLOG("Rcmd: resume\n");
cache_sync(sl);
stlink_run(sl);
ret = stlink_run(sl);
if (ret) {
DLOG("Rcmd: resume failed\n");
reply = strdup("E00");

} else {
reply = strdup("OK");
}

reply = strdup("OK");
} else if (!strncmp(cmd, "halt", 4)) { //halt
reply = strdup("OK");
ret = stlink_force_debug(sl);
if (ret) {
DLOG("Rcmd: halt failed\n");
reply = strdup("E00");

stlink_force_debug(sl);
} else {
reply = strdup("OK");
DLOG("Rcmd: halt\n");
}

DLOG("Rcmd: halt\n");
} else if (!strncmp(cmd, "jtag_reset", 10)) { //jtag_reset
reply = strdup("OK");

stlink_jtag_reset(sl, 0);
stlink_jtag_reset(sl, 1);
stlink_force_debug(sl);
ret = stlink_jtag_reset(sl, 0);
if (ret) {
DLOG("Rcmd: jtag_reset failed with jtag_reset\n");
reply = strdup("E00");

}

ret = stlink_jtag_reset(sl, 1);
if (ret) {
DLOG("Rcmd: jtag_reset failed with jtag_reset\n");
reply = strdup("E00");

}

DLOG("Rcmd: jtag_reset\n");
ret = stlink_force_debug(sl);
if (ret) {
DLOG("Rcmd: jtag_reset failed with force_debug\n");
reply = strdup("E00");

}
if (strcmp(reply, "E00")) {
// no errors have been found
DLOG("Rcmd: jtag_reset\n");
}
} else if (!strncmp(cmd, "reset", 5)) { //reset
reply = strdup("OK");

stlink_force_debug(sl);
stlink_reset(sl);
ret = stlink_force_debug(sl);
if (ret) {
DLOG("Rcmd: reset failed with force_debug\n");
reply = strdup("E00");
}

ret = stlink_reset(sl);
if (ret) {
DLOG("Rcmd: reset failed with reset\n");
reply = strdup("E00");
}

init_code_breakpoints(sl);
init_data_watchpoints(sl);

DLOG("Rcmd: reset\n");
if (reply == NULL) {
reply = strdup("OK");
DLOG("Rcmd: reset\n");
}

} else if (!strncmp(cmd, "semihosting ", 12)) {
DLOG("Rcmd: got semihosting cmd '%s'", cmd);
char *arg = cmd + 12;
Expand Down Expand Up @@ -1369,7 +1417,10 @@ int serve(stlink_t *sl, st_state_t *st) {

case 'c':
cache_sync(sl);
stlink_run(sl);
ret = stlink_run(sl);
if (ret) {
DLOG("Semihost: run failed\n");
}

while(1) {
status = gdb_check_for_interrupt(client);
Expand All @@ -1384,10 +1435,12 @@ int serve(stlink_t *sl, st_state_t *st) {
break;
}

stlink_status(sl);
ret = stlink_status(sl);
if (ret) {
DLOG("Semihost: status failed\n");
}
if(sl->core_stat == STLINK_CORE_HALTED) {
struct stlink_reg reg;
int ret;
stm32_addr_t pc;
stm32_addr_t addr;
int offset = 0;
Expand All @@ -1397,7 +1450,10 @@ int serve(stlink_t *sl, st_state_t *st) {
break;
}

stlink_read_all_regs (sl, &reg);
ret = stlink_read_all_regs (sl, &reg);
if (ret) {
DLOG("Semihost: read_all_regs failed\n");
}

/* Read PC */
pc = reg.r[15];
Expand All @@ -1421,17 +1477,29 @@ int serve(stlink_t *sl, st_state_t *st) {

if (insn == 0xBEAB && !has_breakpoint(addr)) {

do_semihosting (sl, reg.r[0], reg.r[1], &reg.r[0]);
ret = do_semihosting (sl, reg.r[0], reg.r[1], &reg.r[0]);
if (ret) {
DLOG("Semihost: do_semihosting failed\n");
}

/* Write return value */
stlink_write_reg(sl, reg.r[0], 0);
ret = stlink_write_reg(sl, reg.r[0], 0);
if (ret) {
DLOG("Semihost: write_reg failed for return value\n");
}

/* Jump over the break instruction */
stlink_write_reg(sl, reg.r[15] + 2, 15);
ret = stlink_write_reg(sl, reg.r[15] + 2, 15);
if (ret) {
DLOG("Semihost: write_reg failed for jumping over break\n");
}

/* continue execution */
cache_sync(sl);
stlink_run(sl);
ret = stlink_run(sl);
if (ret) {
DLOG("Semihost: continue execution failed with stlink_run\n");
}
} else {
break;
}
Expand All @@ -1444,10 +1512,17 @@ int serve(stlink_t *sl, st_state_t *st) {
break;

case 's':
cache_sync(sl);
stlink_step(sl);
cache_sync(sl);
ret = stlink_step(sl);
if (ret) {
// have problem sending step packet
ELOG("Step: cannot send step request\n");
reply = strdup("E00");
critical_error = 1; // absolutely critical
} else {
reply = strdup("S05"); // TRAP
}

reply = strdup("S05"); // TRAP
break;

case '?':
Expand All @@ -1460,7 +1535,10 @@ int serve(stlink_t *sl, st_state_t *st) {
break;

case 'g':
stlink_read_all_regs(sl, &regp);
ret = stlink_read_all_regs(sl, &regp);
if (ret) {
DLOG("g packet: read_all_regs failed\n");
}

reply = calloc(8 * 16 + 1, 1);
for(int i = 0; i < 16; i++)
Expand All @@ -1473,41 +1551,48 @@ int serve(stlink_t *sl, st_state_t *st) {
unsigned myreg = 0xDEADDEAD;

if(id < 16) {
stlink_read_reg(sl, id, &regp);
ret = stlink_read_reg(sl, id, &regp);
myreg = htonl(regp.r[id]);
} else if(id == 0x19) {
stlink_read_reg(sl, 16, &regp);
ret = stlink_read_reg(sl, 16, &regp);
myreg = htonl(regp.xpsr);
} else if(id == 0x1A) {
stlink_read_reg(sl, 17, &regp);
ret = stlink_read_reg(sl, 17, &regp);
myreg = htonl(regp.main_sp);
} else if(id == 0x1B) {
stlink_read_reg(sl, 18, &regp);
ret = stlink_read_reg(sl, 18, &regp);
myreg = htonl(regp.process_sp);
} else if(id == 0x1C) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.control);
} else if(id == 0x1D) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.faultmask);
} else if(id == 0x1E) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.basepri);
} else if(id == 0x1F) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.primask);
} else if(id >= 0x20 && id < 0x40) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.s[id-0x20]);
} else if(id == 0x40) {
stlink_read_unsupported_reg(sl, id, &regp);
ret = stlink_read_unsupported_reg(sl, id, &regp);
myreg = htonl(regp.fpscr);
} else {
ret = 1;
reply = strdup("E00");
}
if (ret) {
DLOG("p packet: stlink_read_unsupported_reg failed with id %u\n", id);
}

reply = calloc(8 + 1, 1);
sprintf(reply, "%08x", myreg);
if (reply == NULL) {
// if reply is set to "E00", skip
reply = calloc(8 + 1, 1);
sprintf(reply, "%08x", myreg);
}

break;
}
Expand All @@ -1519,31 +1604,36 @@ int serve(stlink_t *sl, st_state_t *st) {
unsigned reg = (unsigned int) strtoul(s_reg, NULL, 16);
unsigned value = (unsigned int) strtoul(s_value, NULL, 16);


if(reg < 16) {
stlink_write_reg(sl, ntohl(value), reg);
ret = stlink_write_reg(sl, ntohl(value), reg);
} else if(reg == 0x19) {
stlink_write_reg(sl, ntohl(value), 16);
ret = stlink_write_reg(sl, ntohl(value), 16);
} else if(reg == 0x1A) {
stlink_write_reg(sl, ntohl(value), 17);
ret = stlink_write_reg(sl, ntohl(value), 17);
} else if(reg == 0x1B) {
stlink_write_reg(sl, ntohl(value), 18);
ret = stlink_write_reg(sl, ntohl(value), 18);
} else if(reg == 0x1C) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else if(reg == 0x1D) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else if(reg == 0x1E) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else if(reg == 0x1F) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else if(reg >= 0x20 && reg < 0x40) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else if(reg == 0x40) {
stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
ret = stlink_write_unsupported_reg(sl, ntohl(value), reg, &regp);
} else {
ret = 1;
reply = strdup("E00");
}

if(!reply) {
if (ret) {
DLOG("P packet: stlink_write_unsupported_reg failed with reg %u\n", reg);
}
if(reply == NULL) {
// note that NULL may not be zero
reply = strdup("OK");
}

Expand All @@ -1555,7 +1645,10 @@ int serve(stlink_t *sl, st_state_t *st) {
char str[9] = {0};
strncpy(str, &packet[1 + i * 8], 8);
uint32_t reg = (uint32_t) strtoul(str, NULL, 16);
stlink_write_reg(sl, ntohl(reg), i);
ret = stlink_write_reg(sl, ntohl(reg), i);
if (ret) {
DLOG("G packet: stlink_write_reg failed");
}
}

reply = strdup("OK");
Expand Down Expand Up @@ -1729,9 +1822,13 @@ int serve(stlink_t *sl, st_state_t *st) {
}

case 'R': {

/* Reset the core. */

stlink_reset(sl);
ret = stlink_reset(sl);
if (ret) {
DLOG("R packet : stlink_reset failed\n");
}
init_code_breakpoints(sl);
init_data_watchpoints(sl);

Expand All @@ -1743,8 +1840,15 @@ int serve(stlink_t *sl, st_state_t *st) {
}
case 'k':
/* Kill request - reset the connection itself */
stlink_run(sl);
stlink_exit_debug_mode(sl);
ret = stlink_run(sl);
if (ret) {
DLOG("Kill: stlink_run failed\n");
}

ret = stlink_exit_debug_mode(sl);
if (ret) {
DLOG("Kill: stlink_exit_debug_mode failed\n");
}
stlink_close(sl);

sl = do_connect(st);
Expand All @@ -1754,7 +1858,10 @@ int serve(stlink_t *sl, st_state_t *st) {
if (st->reset) {
stlink_reset(sl);
}
stlink_force_debug(sl);
ret = stlink_force_debug(sl);
if (ret) {
DLOG("Kill: stlink_force_debug failed\n");
}
init_cache(sl);
init_code_breakpoints(sl);
init_data_watchpoints(sl);
Expand Down Expand Up @@ -1782,6 +1889,11 @@ int serve(stlink_t *sl, st_state_t *st) {
free(reply);
}

if (critical_error) {
close_socket(client);
return 1;
}

free(packet);
}

Expand Down