6 #include <sys/socket.h>
17 #include "gdbserver.h"
20 #define C_EBREAK 0x9002
21 #define EBREAK 0x00100073
23 //////////////////////////////////////// Utility Functions
25 void die(const char* msg
)
27 fprintf(stderr
, "gdbserver code died: %s\n", msg
);
31 // gdb's register list is defined in riscv_gdb_reg_names gdb/riscv-tdep.c in
32 // its source tree. We must interpret the numbers the same here.
44 //////////////////////////////////////// Functions to generate RISC-V opcodes.
46 // TODO: Does this already exist somewhere?
48 // Using regnames.cc as source. The RVG Calling Convention of the 2.0 RISC-V
49 // spec says it should be 2 and 3.
52 static uint32_t bits(uint32_t value
, unsigned int hi
, unsigned int lo
) {
53 return (value
>> lo
) & ((1 << (hi
+1-lo
)) - 1);
56 static uint32_t bit(uint32_t value
, unsigned int b
) {
57 return (value
>> b
) & 1;
60 static uint32_t jal(unsigned int rd
, uint32_t imm
) {
61 return (bit(imm
, 20) << 31) |
62 (bits(imm
, 10, 1) << 21) |
63 (bit(imm
, 11) << 20) |
64 (bits(imm
, 19, 12) << 12) |
69 static uint32_t csrsi(unsigned int csr
, uint8_t imm
) {
71 (bits(imm
, 4, 0) << 15) |
75 static uint32_t csrr(unsigned int rd
, unsigned int csr
) {
76 return (csr
<< 20) | (rd
<< 7) | MATCH_CSRRS
;
79 static uint32_t sw(unsigned int src
, unsigned int base
, uint16_t offset
)
81 return (bits(offset
, 11, 5) << 25) |
84 (bits(offset
, 4, 0) << 7) |
88 static uint32_t sd(unsigned int src
, unsigned int base
, uint16_t offset
)
90 return (bits(offset
, 11, 5) << 25) |
91 (bits(src
, 4, 0) << 20) |
93 (bits(offset
, 4, 0) << 7) |
98 unsigned int circular_buffer_t
<T
>::size() const
103 return end
+ capacity
- start
;
106 template <typename T
>
107 void circular_buffer_t
<T
>::consume(unsigned int bytes
)
109 start
= (start
+ bytes
) % capacity
;
112 template <typename T
>
113 unsigned int circular_buffer_t
<T
>::contiguous_empty_size() const
117 return capacity
- end
- 1;
119 return capacity
- end
;
121 return start
- end
- 1;
124 template <typename T
>
125 unsigned int circular_buffer_t
<T
>::contiguous_data_size() const
130 return capacity
- start
;
133 template <typename T
>
134 void circular_buffer_t
<T
>::data_added(unsigned int bytes
)
137 assert(end
<= capacity
);
142 template <typename T
>
143 void circular_buffer_t
<T
>::reset()
149 template <typename T
>
150 void circular_buffer_t
<T
>::append(const T
*src
, unsigned int count
)
152 unsigned int copy
= std::min(count
, contiguous_empty_size());
153 memcpy(contiguous_empty(), src
, copy
* sizeof(T
));
157 assert(count
< contiguous_empty_size());
158 memcpy(contiguous_empty(), src
, count
* sizeof(T
));
163 ////////////////////////////// Debug Operations
165 class halt_op_t
: public operation_t
168 halt_op_t(gdbserver_t
& gdbserver
) : operation_t(gdbserver
) {};
172 // TODO: For now we just assume the target is 64-bit.
173 gs
.write_debug_ram(0, csrsi(DCSR_ADDRESS
, DCSR_HALT_MASK
));
174 gs
.write_debug_ram(1, csrr(S0
, DPC_ADDRESS
));
175 gs
.write_debug_ram(2, sd(S0
, 0, (uint16_t) DEBUG_RAM_START
));
176 gs
.write_debug_ram(3, csrr(S0
, DCSR_ADDRESS
));
177 gs
.write_debug_ram(4, sd(S0
, 0, (uint16_t) DEBUG_RAM_START
+ 8));
178 gs
.write_debug_ram(5, jal(0, (uint32_t) (DEBUG_ROM_RESUME
- (DEBUG_RAM_START
+ 4*5))));
189 class general_registers_read_op_t
: public operation_t
191 // Register order that gdb expects is:
192 // "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
193 // "x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
194 // "x16", "x17", "x18", "x19", "x20", "x21", "x22", "x23",
195 // "x24", "x25", "x26", "x27", "x28", "x29", "x30", "x31",
197 // Each byte of register data is described by two hex digits. The bytes with
198 // the register are transmitted in target byte order. The size of each
199 // register and their position within the āgā packet are determined by the
200 // gdb internal gdbarch functions DEPRECATED_REGISTER_RAW_SIZE and
201 // gdbarch_register_name.
204 general_registers_read_op_t(gdbserver_t
& gdbserver
) :
205 operation_t(gdbserver
), current_reg(0) {};
211 // x0 is always zero.
214 gs
.write_debug_ram(0, sd(1, 0, (uint16_t) DEBUG_RAM_START
+ 16));
215 gs
.write_debug_ram(1, sd(2, 0, (uint16_t) DEBUG_RAM_START
+ 0));
216 gs
.write_debug_ram(2, jal(0, (uint32_t) (DEBUG_ROM_RESUME
- (DEBUG_RAM_START
+ 4*2))));
224 fprintf(stderr
, "step %d\n", current_reg
);
225 gs
.send(((uint64_t) gs
.read_debug_ram(5) << 32) | gs
.read_debug_ram(4));
226 if (current_reg
>= 31) {
231 gs
.send(((uint64_t) gs
.read_debug_ram(1) << 32) | gs
.read_debug_ram(0));
234 // TODO properly read s0 and s1
235 gs
.write_debug_ram(0, sd(current_reg
, 0, (uint16_t) DEBUG_RAM_START
+ 16));
236 gs
.write_debug_ram(1, sd(current_reg
+1, 0, (uint16_t) DEBUG_RAM_START
+ 0));
237 gs
.write_debug_ram(2, jal(0, (uint32_t) (DEBUG_ROM_RESUME
- (DEBUG_RAM_START
+ 4*2))));
244 unsigned int current_reg
;
247 class register_read_op_t
: public operation_t
250 register_read_op_t(gdbserver_t
& gdbserver
, unsigned int reg
) :
251 operation_t(gdbserver
), reg(reg
) {};
255 if (reg
>= REG_XPR0
&& reg
<= REG_XPR31
) {
256 die("handle_register_read");
257 // send(p->state.XPR[reg - REG_XPR0]);
258 } else if (reg
== REG_PC
) {
259 gs
.write_debug_ram(0, csrr(S0
, DPC_ADDRESS
));
260 gs
.write_debug_ram(1, sd(S0
, 0, (uint16_t) DEBUG_RAM_START
));
261 gs
.write_debug_ram(2, jal(0, (uint32_t) (DEBUG_ROM_RESUME
- (DEBUG_RAM_START
+ 4*2))));
263 } else if (reg
>= REG_FPR0
&& reg
<= REG_FPR31
) {
264 die("handle_register_read");
265 // send(p->state.FPR[reg - REG_FPR0]);
266 } else if (reg
>= REG_CSR0
&& reg
<= REG_CSR4095
) {
268 die("handle_register_read");
269 // send(p->get_csr(reg - REG_CSR0));
271 // It would be nicer to return an error here, but if you do that then gdb
272 // exits out of 'info registers all' as soon as it encounters a register
273 // that can't be read.
279 gs
.send_packet("E02");
289 gs
.send(((uint64_t) gs
.read_debug_ram(1) << 32) | gs
.read_debug_ram(0));
298 ////////////////////////////// gdbserver itself
300 gdbserver_t::gdbserver_t(uint16_t port
, sim_t
*sim
) :
303 recv_buf(64 * 1024), send_buf(64 * 1024),
306 socket_fd
= socket(AF_INET
, SOCK_STREAM
, 0);
307 if (socket_fd
== -1) {
308 fprintf(stderr
, "failed to make socket: %s (%d)\n", strerror(errno
), errno
);
312 fcntl(socket_fd
, F_SETFL
, O_NONBLOCK
);
314 if (setsockopt(socket_fd
, SOL_SOCKET
, SO_REUSEADDR
, &reuseaddr
,
315 sizeof(int)) == -1) {
316 fprintf(stderr
, "failed setsockopt: %s (%d)\n", strerror(errno
), errno
);
320 struct sockaddr_in addr
;
321 memset(&addr
, 0, sizeof(addr
));
322 addr
.sin_family
= AF_INET
;
323 addr
.sin_addr
.s_addr
= INADDR_ANY
;
324 addr
.sin_port
= htons(port
);
326 if (bind(socket_fd
, (struct sockaddr
*) &addr
, sizeof(addr
)) == -1) {
327 fprintf(stderr
, "failed to bind socket: %s (%d)\n", strerror(errno
), errno
);
331 if (listen(socket_fd
, 1) == -1) {
332 fprintf(stderr
, "failed to listen on socket: %s (%d)\n", strerror(errno
), errno
);
337 void gdbserver_t::write_debug_ram(unsigned int index
, uint32_t value
)
339 sim
->debug_module
.ram_write32(index
, value
);
342 uint32_t gdbserver_t::read_debug_ram(unsigned int index
)
344 return sim
->debug_module
.ram_read32(index
);
347 void gdbserver_t::set_operation(operation_t
* operation
)
349 assert(this->operation
== NULL
|| operation
== NULL
);
350 if (operation
&& operation
->start()) {
353 this->operation
= operation
;
357 void gdbserver_t::accept()
359 client_fd
= ::accept(socket_fd
, NULL
, NULL
);
360 if (client_fd
== -1) {
361 if (errno
== EAGAIN
) {
362 // No client waiting to connect right now.
364 fprintf(stderr
, "failed to accept on socket: %s (%d)\n", strerror(errno
),
369 fcntl(client_fd
, F_SETFL
, O_NONBLOCK
);
372 extended_mode
= false;
374 // gdb wants the core to be halted when it attaches.
375 set_operation(new halt_op_t(*this));
379 void gdbserver_t::read()
381 // Reading from a non-blocking socket still blocks if there is no data
384 size_t count
= recv_buf
.contiguous_empty_size();
386 ssize_t bytes
= ::read(client_fd
, recv_buf
.contiguous_empty(), count
);
388 if (errno
== EAGAIN
) {
389 // We'll try again the next call.
391 fprintf(stderr
, "failed to read on socket: %s (%d)\n", strerror(errno
), errno
);
394 } else if (bytes
== 0) {
395 // The remote disconnected.
397 processor_t
*p
= sim
->get_core(0);
398 // TODO p->set_halted(false, HR_NONE);
402 recv_buf
.data_added(bytes
);
406 void gdbserver_t::write()
408 if (send_buf
.empty())
411 while (!send_buf
.empty()) {
412 unsigned int count
= send_buf
.contiguous_data_size();
414 ssize_t bytes
= ::write(client_fd
, send_buf
.contiguous_data(), count
);
416 fprintf(stderr
, "failed to write to socket: %s (%d)\n", strerror(errno
), errno
);
418 } else if (bytes
== 0) {
419 // Client can't take any more data right now.
422 fprintf(stderr
, "wrote %ld bytes: ", bytes
);
423 for (unsigned int i
= 0; i
< bytes
; i
++) {
424 fprintf(stderr
, "%c", send_buf
[i
]);
426 fprintf(stderr
, "\n");
427 send_buf
.consume(bytes
);
432 void print_packet(const std::vector
<uint8_t> &packet
)
434 for (uint8_t c
: packet
) {
435 if (c
>= ' ' and c
<= '~')
436 fprintf(stderr
, "%c", c
);
438 fprintf(stderr
, "\\x%x", c
);
440 fprintf(stderr
, "\n");
443 uint8_t compute_checksum(const std::vector
<uint8_t> &packet
)
445 uint8_t checksum
= 0;
446 for (auto i
= packet
.begin() + 1; i
!= packet
.end() - 3; i
++ ) {
452 uint8_t character_hex_value(uint8_t character
)
454 if (character
>= '0' && character
<= '9')
455 return character
- '0';
456 if (character
>= 'a' && character
<= 'f')
457 return 10 + character
- 'a';
458 if (character
>= 'A' && character
<= 'F')
459 return 10 + character
- 'A';
463 uint8_t extract_checksum(const std::vector
<uint8_t> &packet
)
465 return character_hex_value(*(packet
.end() - 1)) +
466 16 * character_hex_value(*(packet
.end() - 2));
469 void gdbserver_t::process_requests()
471 // See https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
473 while (!recv_buf
.empty()) {
474 std::vector
<uint8_t> packet
;
475 for (unsigned int i
= 0; i
< recv_buf
.size(); i
++) {
476 uint8_t b
= recv_buf
[i
];
478 if (packet
.empty() && expect_ack
&& b
== '+') {
483 if (packet
.empty() && b
== 3) {
484 fprintf(stderr
, "Received interrupt\n");
491 // Start of new packet.
492 if (!packet
.empty()) {
493 fprintf(stderr
, "Received malformed %ld-byte packet from debug client: ",
495 print_packet(packet
);
503 // Packets consist of $<packet-data>#<checksum>
504 // where <checksum> is
505 if (packet
.size() >= 4 &&
506 packet
[packet
.size()-3] == '#') {
507 handle_packet(packet
);
508 recv_buf
.consume(i
+1);
512 // There's a partial packet in the buffer. Wait until we get more data to
520 void gdbserver_t::handle_halt_reason(const std::vector
<uint8_t> &packet
)
525 void gdbserver_t::handle_general_registers_read(const std::vector
<uint8_t> &packet
)
527 set_operation(new general_registers_read_op_t(*this));
530 void gdbserver_t::set_interrupt(uint32_t hartid
) {
531 sim
->debug_module
.set_interrupt(hartid
);
534 // First byte is the most-significant one.
535 // Eg. "08675309" becomes 0x08675309.
536 uint64_t consume_hex_number(std::vector
<uint8_t>::const_iterator
&iter
,
537 std::vector
<uint8_t>::const_iterator end
)
541 while (iter
!= end
) {
543 uint64_t c_value
= character_hex_value(c
);
553 // First byte is the least-significant one.
554 // Eg. "08675309" becomes 0x09536708
555 uint64_t consume_hex_number_le(std::vector
<uint8_t>::const_iterator
&iter
,
556 std::vector
<uint8_t>::const_iterator end
)
559 unsigned int shift
= 4;
561 while (iter
!= end
) {
563 uint64_t c_value
= character_hex_value(c
);
567 value
|= c_value
<< shift
;
568 if ((shift
% 8) == 0)
576 void consume_string(std::string
&str
, std::vector
<uint8_t>::const_iterator
&iter
,
577 std::vector
<uint8_t>::const_iterator end
, uint8_t separator
)
579 while (iter
!= end
&& *iter
!= separator
) {
580 str
.append(1, (char) *iter
);
585 void gdbserver_t::handle_register_read(const std::vector
<uint8_t> &packet
)
589 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
590 unsigned int n
= consume_hex_number(iter
, packet
.end());
592 return send_packet("E01");
594 set_operation(new register_read_op_t(*this, n
));
597 void gdbserver_t::handle_register_write(const std::vector
<uint8_t> &packet
)
601 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
602 unsigned int n
= consume_hex_number(iter
, packet
.end());
604 return send_packet("E05");
607 reg_t value
= consume_hex_number_le(iter
, packet
.end());
609 return send_packet("E06");
611 processor_t
*p
= sim
->get_core(0);
613 die("handle_register_write");
615 if (n >= REG_XPR0 && n <= REG_XPR31) {
616 p->state.XPR.write(n - REG_XPR0, value);
617 } else if (n == REG_PC) {
619 } else if (n >= REG_FPR0 && n <= REG_FPR31) {
620 p->state.FPR.write(n - REG_FPR0, value);
621 } else if (n >= REG_CSR0 && n <= REG_CSR4095) {
623 p->set_csr(n - REG_CSR0, value);
625 return send_packet("EFF");
628 return send_packet("E07");
632 return send_packet("OK");
635 void gdbserver_t::handle_memory_read(const std::vector
<uint8_t> &packet
)
638 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
639 reg_t address
= consume_hex_number(iter
, packet
.end());
641 return send_packet("E10");
643 reg_t length
= consume_hex_number(iter
, packet
.end());
645 return send_packet("E11");
649 processor_t
*p
= sim
->get_core(0);
650 mmu_t
* mmu
= sim
->debug_mmu
;
652 for (reg_t i
= 0; i
< length
; i
++) {
653 sprintf(buffer
, "%02x", mmu
->load_uint8(address
+ i
));
659 void gdbserver_t::handle_memory_binary_write(const std::vector
<uint8_t> &packet
)
661 // X addr,length:XX...
662 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
663 reg_t address
= consume_hex_number(iter
, packet
.end());
665 return send_packet("E20");
667 reg_t length
= consume_hex_number(iter
, packet
.end());
669 return send_packet("E21");
672 processor_t
*p
= sim
->get_core(0);
673 mmu_t
* mmu
= sim
->debug_mmu
;
674 for (unsigned int i
= 0; i
< length
; i
++) {
675 if (iter
== packet
.end()) {
676 return send_packet("E22");
678 mmu
->store_uint8(address
+ i
, *iter
);
682 return send_packet("E4b"); // EOVERFLOW
687 void gdbserver_t::handle_continue(const std::vector
<uint8_t> &packet
)
690 processor_t
*p
= sim
->get_core(0);
691 if (packet
[2] != '#') {
692 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
693 die("handle_continue");
694 // p->state.pc = consume_hex_number(iter, packet.end());
696 return send_packet("E30");
699 // TODO p->set_halted(false, HR_NONE);
700 // TODO running = true;
703 void gdbserver_t::handle_step(const std::vector
<uint8_t> &packet
)
706 processor_t
*p
= sim
->get_core(0);
707 if (packet
[2] != '#') {
708 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
710 //p->state.pc = consume_hex_number(iter, packet.end());
712 return send_packet("E40");
715 // TODO: p->set_single_step(true);
716 // TODO running = true;
719 void gdbserver_t::handle_kill(const std::vector
<uint8_t> &packet
)
722 // The exact effect of this packet is not specified.
723 // Looks like OpenOCD disconnects?
727 void gdbserver_t::handle_extended(const std::vector
<uint8_t> &packet
)
729 // Enable extended mode. In extended mode, the remote server is made
730 // persistent. The āRā packet is used to restart the program being debugged.
732 extended_mode
= true;
735 void software_breakpoint_t::insert(mmu_t
* mmu
)
738 instruction
= mmu
->load_uint16(address
);
739 mmu
->store_uint16(address
, C_EBREAK
);
741 instruction
= mmu
->load_uint32(address
);
742 mmu
->store_uint32(address
, EBREAK
);
744 fprintf(stderr
, ">>> Read %x from %lx\n", instruction
, address
);
747 void software_breakpoint_t::remove(mmu_t
* mmu
)
749 fprintf(stderr
, ">>> write %x to %lx\n", instruction
, address
);
751 mmu
->store_uint16(address
, instruction
);
753 mmu
->store_uint32(address
, instruction
);
757 void gdbserver_t::handle_breakpoint(const std::vector
<uint8_t> &packet
)
759 // insert: Z type,addr,kind
760 // remove: z type,addr,kind
762 software_breakpoint_t bp
;
763 bool insert
= (packet
[1] == 'Z');
764 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
765 int type
= consume_hex_number(iter
, packet
.end());
767 return send_packet("E50");
769 bp
.address
= consume_hex_number(iter
, packet
.end());
771 return send_packet("E51");
773 bp
.size
= consume_hex_number(iter
, packet
.end());
774 // There may be more options after a ; here, but we don't support that.
776 return send_packet("E52");
778 if (bp
.size
!= 2 && bp
.size
!= 4) {
779 return send_packet("E53");
782 processor_t
*p
= sim
->get_core(0);
783 die("handle_breakpoint");
788 breakpoints[bp.address] = bp;
791 bp = breakpoints[bp.address];
793 breakpoints.erase(bp.address);
796 sim->debug_mmu->flush_icache();
798 return send_packet("OK");
801 void gdbserver_t::handle_query(const std::vector
<uint8_t> &packet
)
804 std::vector
<uint8_t>::const_iterator iter
= packet
.begin() + 2;
806 consume_string(name
, iter
, packet
.end(), ':');
807 if (iter
!= packet
.end())
809 if (name
== "Supported") {
811 while (iter
!= packet
.end()) {
813 consume_string(feature
, iter
, packet
.end(), ';');
814 if (iter
!= packet
.end())
816 if (feature
== "swbreak+") {
823 fprintf(stderr
, "Unsupported query %s\n", name
.c_str());
824 return send_packet("");
827 void gdbserver_t::handle_packet(const std::vector
<uint8_t> &packet
)
829 if (compute_checksum(packet
) != extract_checksum(packet
)) {
830 fprintf(stderr
, "Received %ld-byte packet with invalid checksum\n", packet
.size());
831 fprintf(stderr
, "Computed checksum: %x\n", compute_checksum(packet
));
832 print_packet(packet
);
837 fprintf(stderr
, "Received %ld-byte packet from debug client: ", packet
.size());
838 print_packet(packet
);
843 return handle_extended(packet
);
845 return handle_halt_reason(packet
);
847 return handle_general_registers_read(packet
);
849 return handle_kill(packet
);
851 return handle_memory_read(packet
);
853 // return handle_memory_write(packet);
855 return handle_memory_binary_write(packet
);
857 return handle_register_read(packet
);
859 return handle_register_write(packet
);
861 return handle_continue(packet
);
863 return handle_step(packet
);
866 return handle_breakpoint(packet
);
869 return handle_query(packet
);
873 fprintf(stderr
, "** Unsupported packet: ");
874 print_packet(packet
);
878 void gdbserver_t::handle_interrupt()
880 processor_t
*p
= sim
->get_core(0);
881 // TODO p->set_halted(true, HR_INTERRUPT);
882 send_packet("S02"); // Pretend program received SIGINT.
883 // TODO running = false;
886 void gdbserver_t::handle()
889 processor_t
*p
= sim
->get_core(0);
891 bool interrupt
= sim
->debug_module
.get_interrupt(0);
894 if (operation
&& operation
->step()) {
902 // gdb requested a halt and now it's done.
904 fprintf(stderr, "DPC: 0x%x\n", read_debug_ram(0));
905 fprintf(stderr, "DCSR: 0x%x\n", read_debug_ram(2));
906 state = STATE_HALTED;
913 if (running && p->halted) {
914 // The core was running, but now it's halted. Better tell gdb.
915 switch (p->halt_reason) {
917 fprintf(stderr, "Internal error. Processor halted without reason.\n");
923 // There's no gdb code for this.
927 send_packet("T05swbreak:;");
931 // TODO: Actually include register values here
944 this->process_requests();
948 void gdbserver_t::send(const char* msg
)
950 unsigned int length
= strlen(msg
);
951 for (const char *c
= msg
; *c
; c
++)
952 running_checksum
+= *c
;
953 send_buf
.append((const uint8_t *) msg
, length
);
956 void gdbserver_t::send(uint64_t value
)
959 for (unsigned int i
= 0; i
< 8; i
++) {
960 sprintf(buffer
, "%02x", (int) (value
& 0xff));
966 void gdbserver_t::send(uint32_t value
)
969 for (unsigned int i
= 0; i
< 4; i
++) {
970 sprintf(buffer
, "%02x", (int) (value
& 0xff));
976 void gdbserver_t::send_packet(const char* data
)
984 void gdbserver_t::start_packet()
987 running_checksum
= 0;
990 void gdbserver_t::end_packet(const char* data
)
996 char checksum_string
[4];
997 sprintf(checksum_string
, "#%02x", running_checksum
);
998 send(checksum_string
);