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- /******************************************************************************
- * Copyright 2015 Espressif Systems
- *
- * Description: A stub to make the ESP8266 debuggable by GDB over the serial
- * port.
- *
- * License: ESPRESSIF MIT License
- *******************************************************************************/
- #include "ets_sys.h"
- #include "eagle_soc.h"
- #include "c_types.h"
- #include "gpio.h"
- #include "xtensa/corebits.h"
- #include "gdbstub/gdbstub.h"
- #include "gdbstub/gdbstub-entry.h"
- #include "gdbstub/gdbstub-cfg.h"
- //From xtruntime-frames.h
- struct XTensa_exception_frame_s {
- uint32_t pc;
- uint32_t ps;
- uint32_t sar;
- uint32_t vpri;
- uint32_t a0;
- uint32_t a[14]; //a2..a15
- //These are added manually by the exception code; the HAL doesn't set these on an exception.
- uint32_t litbase;
- uint32_t sr176;
- uint32_t sr208;
- uint32_t a1;
- //'reason' is abused for both the debug and the exception vector: if bit 7 is set,
- //this contains an exception reason, otherwise it contains a debug vector bitmap.
- uint32_t reason;
- };
- struct XTensa_rtos_int_frame_s {
- uint32_t exitPtr;
- uint32_t pc;
- uint32_t ps;
- uint32_t a[16];
- uint32_t sar;
- };
- #if GDBSTUB_FREERTOS
- /*
- Definitions for FreeRTOS. This redefines some os_* functions to use their non-os* counterparts. It
- also sets up some function pointers for ROM functions that aren't in the FreeRTOS ld files.
- */
- #include <string.h>
- #include <stdio.h>
- void _xt_isr_attach(int inum, void *fn);
- void _xt_isr_unmask(int inum);
- void os_install_putc1(void (*p)(char c));
- #define os_printf(...) printf(__VA_ARGS__)
- #define os_memcpy(a,b,c) memcpy(a,b,c)
- typedef void wdtfntype();
- static wdtfntype *ets_wdt_disable=(wdtfntype *)0x400030f0;
- static wdtfntype *ets_wdt_enable=(wdtfntype *)0x40002fa0;
- #else
- /*
- OS-less SDK defines. Defines some headers for things that aren't in the include files, plus
- the xthal stack frame struct.
- */
- #include "osapi.h"
- #include "user_interface.h"
- void _xtos_set_exception_handler(int cause, void (exhandler)(struct XTensa_exception_frame_s *frame));
- int os_printf_plus(const char *format, ...) __attribute__ ((format (printf, 1, 2)));
- #endif
- #define EXCEPTION_GDB_SP_OFFSET 0x100
- //We need some UART register defines.
- #define ETS_UART_INUM 5
- #define REG_UART_BASE( i ) (0x60000000+(i)*0xf00)
- #define UART_STATUS( i ) (REG_UART_BASE( i ) + 0x1C)
- #define UART_RXFIFO_CNT 0x000000FF
- #define UART_RXFIFO_CNT_S 0
- #define UART_TXFIFO_CNT 0x000000FF
- #define UART_TXFIFO_CNT_S 16
- #define UART_FIFO( i ) (REG_UART_BASE( i ) + 0x0)
- #define UART_INT_ENA(i) (REG_UART_BASE(i) + 0xC)
- #define UART_INT_CLR(i) (REG_UART_BASE(i) + 0x10)
- #define UART_RXFIFO_TOUT_INT_ENA (BIT(8))
- #define UART_RXFIFO_FULL_INT_ENA (BIT(0))
- #define UART_RXFIFO_TOUT_INT_CLR (BIT(8))
- #define UART_RXFIFO_FULL_INT_CLR (BIT(0))
- //Length of buffer used to reserve GDB commands. Has to be at least able to fit the G command, which
- //implies a minimum size of about 190 bytes.
- #define PBUFLEN 256
- //Length of gdb stdout buffer, for console redirection
- #define OBUFLEN 32
- //The asm stub saves the Xtensa registers here when a debugging exception happens.
- struct XTensa_exception_frame_s gdbstub_savedRegs;
- #if GDBSTUB_USE_OWN_STACK
- //This is the debugging exception stack.
- int exceptionStack[256];
- #endif
- static unsigned char cmd[PBUFLEN]; //GDB command input buffer
- static char chsum; //Running checksum of the output packet
- #if GDBSTUB_REDIRECT_CONSOLE_OUTPUT
- static unsigned char obuf[OBUFLEN]; //GDB stdout buffer
- static int obufpos=0; //Current position in the buffer
- #endif
- static int32_t singleStepPs=-1; //Stores ps when single-stepping instruction. -1 when not in use.
- //Small function to feed the hardware watchdog. Needed to stop the ESP from resetting
- //due to a watchdog timeout while reading a command.
- static void ATTR_GDBFN keepWDTalive() {
- uint64_t *wdtval=(uint64_t*)0x3ff21048;
- uint64_t *wdtovf=(uint64_t*)0x3ff210cc;
- int *wdtctl=(int*)0x3ff210c8;
- *wdtovf=*wdtval+1600000;
- *wdtctl|=(1<<31);
- }
- //Receive a char from the uart. Uses polling and feeds the watchdog.
- static int ATTR_GDBFN gdbRecvChar() {
- int i;
- while (((READ_PERI_REG(UART_STATUS(0))>>UART_RXFIFO_CNT_S)&UART_RXFIFO_CNT)==0) {
- keepWDTalive();
- }
- i=READ_PERI_REG(UART_FIFO(0));
- return i;
- }
- //Send a char to the uart.
- static void ATTR_GDBFN gdbSendChar(char c) {
- while (((READ_PERI_REG(UART_STATUS(0))>>UART_TXFIFO_CNT_S)&UART_TXFIFO_CNT)>=126) ;
- WRITE_PERI_REG(UART_FIFO(0), c);
- }
- //Send the start of a packet; reset checksum calculation.
- static void ATTR_GDBFN gdbPacketStart() {
- chsum=0;
- gdbSendChar('$');
- }
- //Send a char as part of a packet
- static void ATTR_GDBFN gdbPacketChar(char c) {
- if (c=='#' || c=='$' || c=='}' || c=='*') {
- gdbSendChar('}');
- gdbSendChar(c^0x20);
- chsum+=(c^0x20)+'}';
- } else {
- gdbSendChar(c);
- chsum+=c;
- }
- }
- //Send a string as part of a packet
- static void ATTR_GDBFN gdbPacketStr(char *c) {
- while (*c!=0) {
- gdbPacketChar(*c);
- c++;
- }
- }
- //Send a hex val as part of a packet. 'bits'/4 dictates the number of hex chars sent.
- static void ATTR_GDBFN gdbPacketHex(int val, int bits) {
- char hexChars[]="0123456789abcdef";
- int i;
- for (i=bits; i>0; i-=4) {
- gdbPacketChar(hexChars[(val>>(i-4))&0xf]);
- }
- }
- //Finish sending a packet.
- static void ATTR_GDBFN gdbPacketEnd() {
- gdbSendChar('#');
- gdbPacketHex(chsum, 8);
- }
- //Error states used by the routines that grab stuff from the incoming gdb packet
- #define ST_ENDPACKET -1
- #define ST_ERR -2
- #define ST_OK -3
- #define ST_CONT -4
- //Grab a hex value from the gdb packet. Ptr will get positioned on the end
- //of the hex string, as far as the routine has read into it. Bits/4 indicates
- //the max amount of hex chars it gobbles up. Bits can be -1 to eat up as much
- //hex chars as possible.
- static long ATTR_GDBFN gdbGetHexVal(unsigned char **ptr, int bits) {
- int i;
- int no;
- unsigned int v=0;
- char c;
- no=bits/4;
- if (bits==-1) no=64;
- for (i=0; i<no; i++) {
- c=**ptr;
- (*ptr)++;
- if (c>='0' && c<='9') {
- v<<=4;
- v|=(c-'0');
- } else if (c>='A' && c<='F') {
- v<<=4;
- v|=(c-'A')+10;
- } else if (c>='a' && c<='f') {
- v<<=4;
- v|=(c-'a')+10;
- } else if (c=='#') {
- if (bits==-1) {
- (*ptr)--;
- return v;
- }
- return ST_ENDPACKET;
- } else {
- if (bits==-1) {
- (*ptr)--;
- return v;
- }
- return ST_ERR;
- }
- }
- return v;
- }
- //Swap an int into the form gdb wants it
- static int ATTR_GDBFN iswap(int i) {
- int r;
- r=((i>>24)&0xff);
- r|=((i>>16)&0xff)<<8;
- r|=((i>>8)&0xff)<<16;
- r|=((i>>0)&0xff)<<24;
- return r;
- }
- //Read a byte from the ESP8266 memory.
- static unsigned char ATTR_GDBFN readbyte(unsigned int p) {
- int *i=(int*)(p&(~3));
- if (p<0x20000000 || p>=0x60000000) return -1;
- return *i>>((p&3)*8);
- }
- //Write a byte to the ESP8266 memory.
- static void ATTR_GDBFN writeByte(unsigned int p, unsigned char d) {
- int *i=(int*)(p&(~3));
- if (p<0x20000000 || p>=0x60000000) return;
- if ((p&3)==0) *i=(*i&0xffffff00)|(d<<0);
- if ((p&3)==1) *i=(*i&0xffff00ff)|(d<<8);
- if ((p&3)==2) *i=(*i&0xff00ffff)|(d<<16);
- if ((p&3)==3) *i=(*i&0x00ffffff)|(d<<24);
- }
- //Returns 1 if it makes sense to write to addr p
- static int ATTR_GDBFN validWrAddr(int p) {
- if (p>=0x3ff00000 && p<0x40000000) return 1;
- if (p>=0x40100000 && p<0x40140000) return 1;
- if (p>=0x60000000 && p<0x60002000) return 1;
- return 0;
- }
- /*
- Register file in the format lx106 gdb port expects it.
- Inspired by gdb/regformats/reg-xtensa.dat from
- https://github.com/jcmvbkbc/crosstool-NG/blob/lx106-g%2B%2B/overlays/xtensa_lx106.tar
- As decoded by Cesanta.
- */
- struct regfile {
- uint32_t a[16];
- uint32_t pc;
- uint32_t sar;
- uint32_t litbase;
- uint32_t sr176;
- uint32_t sr208;
- uint32_t ps;
- };
- //Send the reason execution is stopped to GDB.
- static void ATTR_GDBFN sendReason() {
- #if 0
- char *reason=""; //default
- #endif
- //exception-to-signal mapping
- char exceptionSignal[]={4,31,11,11,2,6,8,0,6,7,0,0,7,7,7,7};
- int i=0;
- gdbPacketStart();
- gdbPacketChar('T');
- if (gdbstub_savedRegs.reason==0xff) {
- gdbPacketHex(2, 8); //sigint
- } else if (gdbstub_savedRegs.reason&0x80) {
- //We stopped because of an exception. Convert exception code to a signal number and send it.
- i=gdbstub_savedRegs.reason&0x7f;
- if (i<sizeof(exceptionSignal)) gdbPacketHex(exceptionSignal[i], 8); else gdbPacketHex(11, 8);
- } else {
- //We stopped because of a debugging exception.
- gdbPacketHex(5, 8); //sigtrap
- //Current Xtensa GDB versions don't seem to request this, so let's leave it off.
- #if 0
- if (gdbstub_savedRegs.reason&(1<<0)) reason="break";
- if (gdbstub_savedRegs.reason&(1<<1)) reason="hwbreak";
- if (gdbstub_savedRegs.reason&(1<<2)) reason="watch";
- if (gdbstub_savedRegs.reason&(1<<3)) reason="swbreak";
- if (gdbstub_savedRegs.reason&(1<<4)) reason="swbreak";
- gdbPacketStr(reason);
- gdbPacketChar(':');
- //ToDo: watch: send address
- #endif
- }
- gdbPacketEnd();
- }
- //Handle a command as received from GDB.
- static int ATTR_GDBFN gdbHandleCommand(unsigned char *cmd, int len) {
- //Handle a command
- int i, j, k;
- unsigned char *data=cmd+1;
- if (cmd[0]=='g') { //send all registers to gdb
- gdbPacketStart();
- gdbPacketHex(iswap(gdbstub_savedRegs.a0), 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.a1), 32);
- for (i=2; i<16; i++) gdbPacketHex(iswap(gdbstub_savedRegs.a[i-2]), 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.pc), 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.sar), 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.litbase), 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.sr176), 32);
- gdbPacketHex(0, 32);
- gdbPacketHex(iswap(gdbstub_savedRegs.ps), 32);
- gdbPacketEnd();
- } else if (cmd[0]=='G') { //receive content for all registers from gdb
- gdbstub_savedRegs.a0=iswap(gdbGetHexVal(&data, 32));
- gdbstub_savedRegs.a1=iswap(gdbGetHexVal(&data, 32));
- for (i=2; i<16; i++) gdbstub_savedRegs.a[i-2]=iswap(gdbGetHexVal(&data, 32));
- gdbstub_savedRegs.pc=iswap(gdbGetHexVal(&data, 32));
- gdbstub_savedRegs.sar=iswap(gdbGetHexVal(&data, 32));
- gdbstub_savedRegs.litbase=iswap(gdbGetHexVal(&data, 32));
- gdbstub_savedRegs.sr176=iswap(gdbGetHexVal(&data, 32));
- gdbGetHexVal(&data, 32);
- gdbstub_savedRegs.ps=iswap(gdbGetHexVal(&data, 32));
- gdbPacketStart();
- gdbPacketStr("OK");
- gdbPacketEnd();
- } else if (cmd[0]=='m') { //read memory to gdb
- i=gdbGetHexVal(&data, -1);
- data++;
- j=gdbGetHexVal(&data, -1);
- gdbPacketStart();
- for (k=0; k<j; k++) {
- gdbPacketHex(readbyte(i++), 8);
- }
- gdbPacketEnd();
- } else if (cmd[0]=='M') { //write memory from gdb
- i=gdbGetHexVal(&data, -1); //addr
- data++; //skip ,
- j=gdbGetHexVal(&data, -1); //length
- data++; //skip :
- if (validWrAddr(i) && validWrAddr(i+j)) {
- for (k=0; k<j; k++) {
- writeByte(i, gdbGetHexVal(&data, 8));
- i++;
- }
- //Make sure caches are up-to-date. Procedure according to Xtensa ISA document, ISYNC inst desc.
- asm volatile("ISYNC\nISYNC\n");
- gdbPacketStart();
- gdbPacketStr("OK");
- gdbPacketEnd();
- } else {
- //Trying to do a software breakpoint on a flash proc, perhaps?
- gdbPacketStart();
- gdbPacketStr("E01");
- gdbPacketEnd();
- }
- } else if (cmd[0]=='?') { //Reply with stop reason
- sendReason();
- // } else if (strncmp(cmd, "vCont?", 6)==0) {
- // gdbPacketStart();
- // gdbPacketStr("vCont;c;s");
- // gdbPacketEnd();
- } else if (strncmp((char*)cmd, "vCont;c", 7)==0 || cmd[0]=='c') { //continue execution
- return ST_CONT;
- } else if (strncmp((char*)cmd, "vCont;s", 7)==0 || cmd[0]=='s') { //single-step instruction
- //Single-stepping can go wrong if an interrupt is pending, especially when it is e.g. a task switch:
- //the ICOUNT register will overflow in the task switch code. That is why we disable interupts when
- //doing single-instruction stepping.
- singleStepPs=gdbstub_savedRegs.ps;
- gdbstub_savedRegs.ps=(gdbstub_savedRegs.ps & ~0xf)|(XCHAL_DEBUGLEVEL-1);
- gdbstub_icount_ena_single_step();
- return ST_CONT;
- } else if (cmd[0]=='q') { //Extended query
- if (strncmp((char*)&cmd[1], "Supported", 9)==0) { //Capabilities query
- gdbPacketStart();
- gdbPacketStr("swbreak+;hwbreak+;PacketSize=255");
- gdbPacketEnd();
- } else {
- //We don't support other queries.
- gdbPacketStart();
- gdbPacketEnd();
- return ST_ERR;
- }
- } else if (cmd[0]=='Z') { //Set hardware break/watchpoint.
- data+=2; //skip 'x,'
- i=gdbGetHexVal(&data, -1);
- data++; //skip ','
- j=gdbGetHexVal(&data, -1);
- gdbPacketStart();
- if (cmd[1]=='1') { //Set breakpoint
- if (gdbstub_set_hw_breakpoint(i, j)) {
- gdbPacketStr("OK");
- } else {
- gdbPacketStr("E01");
- }
- } else if (cmd[1]=='2' || cmd[1]=='3' || cmd[1]=='4') { //Set watchpoint
- int access=0;
- int mask=0;
- if (cmd[1]=='2') access=2; //write
- if (cmd[1]=='3') access=1; //read
- if (cmd[1]=='4') access=3; //access
- if (j==1) mask=0x3F;
- if (j==2) mask=0x3E;
- if (j==4) mask=0x3C;
- if (j==8) mask=0x38;
- if (j==16) mask=0x30;
- if (j==32) mask=0x20;
- if (j==64) mask=0x00;
- if (mask!=0 && gdbstub_set_hw_watchpoint(i,mask, access)) {
- gdbPacketStr("OK");
- } else {
- gdbPacketStr("E01");
- }
- }
- gdbPacketEnd();
- } else if (cmd[0]=='z') { //Clear hardware break/watchpoint
- data+=2; //skip 'x,'
- i=gdbGetHexVal(&data, -1);
- data++; //skip ','
- j=gdbGetHexVal(&data, -1);
- gdbPacketStart();
- if (cmd[1]=='1') { //hardware breakpoint
- if (gdbstub_del_hw_breakpoint(i)) {
- gdbPacketStr("OK");
- } else {
- gdbPacketStr("E01");
- }
- } else if (cmd[1]=='2' || cmd[1]=='3' || cmd[1]=='4') { //hardware watchpoint
- if (gdbstub_del_hw_watchpoint(i)) {
- gdbPacketStr("OK");
- } else {
- gdbPacketStr("E01");
- }
- }
- gdbPacketEnd();
- } else {
- //We don't recognize or support whatever GDB just sent us.
- gdbPacketStart();
- gdbPacketEnd();
- return ST_ERR;
- }
- return ST_OK;
- }
- //Lower layer: grab a command packet and check the checksum
- //Calls gdbHandleCommand on the packet if the checksum is OK
- //Returns ST_OK on success, ST_ERR when checksum fails, a
- //character if it is received instead of the GDB packet
- //start char.
- static int ATTR_GDBFN gdbReadCommand() {
- unsigned char c;
- unsigned char chsum=0, rchsum;
- unsigned char sentchs[2];
- int p=0;
- unsigned char *ptr;
- c=gdbRecvChar();
- if (c!='$') return c;
- while(1) {
- c=gdbRecvChar();
- if (c=='#') { //end of packet, checksum follows
- cmd[p]=0;
- break;
- }
- chsum+=c;
- if (c=='$') {
- //Wut, restart packet?
- chsum=0;
- p=0;
- continue;
- }
- if (c=='}') { //escape the next char
- c=gdbRecvChar();
- chsum+=c;
- c^=0x20;
- }
- cmd[p++]=c;
- if (p>=PBUFLEN) return ST_ERR;
- }
- //A # has been received. Get and check the received chsum.
- sentchs[0]=gdbRecvChar();
- sentchs[1]=gdbRecvChar();
- ptr=&sentchs[0];
- rchsum=gdbGetHexVal(&ptr, 8);
- // os_printf("c %x r %x\n", chsum, rchsum);
- if (rchsum!=chsum) {
- gdbSendChar('-');
- return ST_ERR;
- } else {
- gdbSendChar('+');
- return gdbHandleCommand(cmd, p);
- }
- }
- //Get the value of one of the A registers
- static unsigned int ATTR_GDBFN getaregval(int reg) {
- if (reg==0) return gdbstub_savedRegs.a0;
- if (reg==1) return gdbstub_savedRegs.a1;
- return gdbstub_savedRegs.a[reg-2];
- }
- //Set the value of one of the A registers
- static void ATTR_GDBFN setaregval(int reg, unsigned int val) {
- os_printf("%x -> %x\n", val, reg);
- if (reg==0) gdbstub_savedRegs.a0=val;
- if (reg==1) gdbstub_savedRegs.a1=val;
- gdbstub_savedRegs.a[reg-2]=val;
- }
- //Emulate the l32i/s32i instruction we're stopped at.
- static void ATTR_GDBFN emulLdSt() {
- unsigned char i0=readbyte(gdbstub_savedRegs.pc);
- unsigned char i1=readbyte(gdbstub_savedRegs.pc+1);
- unsigned char i2=readbyte(gdbstub_savedRegs.pc+2);
- int *p;
- if ((i0&0xf)==2 && (i1&0xf0)==0x20) {
- //l32i
- p=(int*)getaregval(i1&0xf)+(i2*4);
- setaregval(i0>>4, *p);
- gdbstub_savedRegs.pc+=3;
- } else if ((i0&0xf)==0x8) {
- //l32i.n
- p=(int*)getaregval(i1&0xf)+((i1>>4)*4);
- setaregval(i0>>4, *p);
- gdbstub_savedRegs.pc+=2;
- } else if ((i0&0xf)==2 && (i1&0xf0)==0x60) {
- //s32i
- p=(int*)getaregval(i1&0xf)+(i2*4);
- *p=getaregval(i0>>4);
- gdbstub_savedRegs.pc+=3;
- } else if ((i0&0xf)==0x9) {
- //s32i.n
- p=(int*)getaregval(i1&0xf)+((i1>>4)*4);
- *p=getaregval(i0>>4);
- gdbstub_savedRegs.pc+=2;
- } else {
- os_printf("GDBSTUB: No l32i/s32i instruction: %x %x %x. Huh?", i2, i1, i0);
- }
- }
- //We just caught a debug exception and need to handle it. This is called from an assembly
- //routine in gdbstub-entry.S
- void ATTR_GDBFN gdbstub_handle_debug_exception() {
- ets_wdt_disable();
- if (singleStepPs!=-1) {
- //We come here after single-stepping an instruction. Interrupts are disabled
- //for the single step. Re-enable them here.
- gdbstub_savedRegs.ps=(gdbstub_savedRegs.ps&~0xf)|(singleStepPs&0xf);
- singleStepPs=-1;
- }
- sendReason();
- while(gdbReadCommand()!=ST_CONT);
- if ((gdbstub_savedRegs.reason&0x84)==0x4) {
- //We stopped due to a watchpoint. We can't re-execute the current instruction
- //because it will happily re-trigger the same watchpoint, so we emulate it
- //while we're still in debugger space.
- emulLdSt();
- } else if ((gdbstub_savedRegs.reason&0x88)==0x8) {
- //We stopped due to a BREAK instruction. Skip over it.
- //Check the instruction first; gdb may have replaced it with the original instruction
- //if it's one of the breakpoints it set.
- if (readbyte(gdbstub_savedRegs.pc+2)==0 &&
- (readbyte(gdbstub_savedRegs.pc+1)&0xf0)==0x40 &&
- (readbyte(gdbstub_savedRegs.pc)&0x0f)==0x00) {
- gdbstub_savedRegs.pc+=3;
- }
- } else if ((gdbstub_savedRegs.reason&0x90)==0x10) {
- //We stopped due to a BREAK.N instruction. Skip over it, after making sure the instruction
- //actually is a BREAK.N
- if ((readbyte(gdbstub_savedRegs.pc+1)&0xf0)==0xf0 &&
- readbyte(gdbstub_savedRegs.pc)==0x2d) {
- gdbstub_savedRegs.pc+=3;
- }
- }
- ets_wdt_enable();
- }
- #if GDBSTUB_FREERTOS
- //Freetos exception. This routine is called by an assembly routine in gdbstub-entry.S
- void ATTR_GDBFN gdbstub_handle_user_exception() {
- ets_wdt_disable();
- gdbstub_savedRegs.reason|=0x80; //mark as an exception reason
- sendReason();
- while(gdbReadCommand()!=ST_CONT);
- ets_wdt_enable();
- }
- #else
- //Non-OS exception handler. Gets called by the Xtensa HAL.
- static void ATTR_GDBFN gdb_exception_handler(struct XTensa_exception_frame_s *frame) {
- //Save the extra registers the Xtensa HAL doesn't save
- gdbstub_save_extra_sfrs_for_exception();
- //Copy registers the Xtensa HAL did save to gdbstub_savedRegs
- os_memcpy(&gdbstub_savedRegs, frame, 19*4);
- //Credits go to Cesanta for this trick. A1 seems to be destroyed, but because it
- //has a fixed offset from the address of the passed frame, we can recover it.
- gdbstub_savedRegs.a1=(uint32_t)frame+EXCEPTION_GDB_SP_OFFSET;
- gdbstub_savedRegs.reason|=0x80; //mark as an exception reason
- ets_wdt_disable();
- sendReason();
- while(gdbReadCommand()!=ST_CONT);
- ets_wdt_enable();
- //Copy any changed registers back to the frame the Xtensa HAL uses.
- os_memcpy(frame, &gdbstub_savedRegs, 19*4);
- }
- #endif
- #if GDBSTUB_REDIRECT_CONSOLE_OUTPUT
- //Replacement putchar1 routine. Instead of spitting out the character directly, it will buffer up to
- //OBUFLEN characters (or up to a \n, whichever comes earlier) and send it out as a gdb stdout packet.
- static void ATTR_GDBFN gdb_semihost_putchar1(char c) {
- int i;
- obuf[obufpos++]=c;
- if (c=='\n' || obufpos==OBUFLEN) {
- gdbPacketStart();
- gdbPacketChar('O');
- for (i=0; i<obufpos; i++) gdbPacketHex(obuf[i], 8);
- gdbPacketEnd();
- obufpos=0;
- }
- }
- #endif
- #if !GDBSTUB_FREERTOS
- //The OS-less SDK uses the Xtensa HAL to handle exceptions. We can use those functions to catch any
- //fatal exceptions and invoke the debugger when this happens.
- static void ATTR_GDBINIT install_exceptions() {
- int i;
- int exno[]={EXCCAUSE_ILLEGAL, EXCCAUSE_SYSCALL, EXCCAUSE_INSTR_ERROR, EXCCAUSE_LOAD_STORE_ERROR,
- EXCCAUSE_DIVIDE_BY_ZERO, EXCCAUSE_UNALIGNED, EXCCAUSE_INSTR_DATA_ERROR, EXCCAUSE_LOAD_STORE_DATA_ERROR,
- EXCCAUSE_INSTR_ADDR_ERROR, EXCCAUSE_LOAD_STORE_ADDR_ERROR, EXCCAUSE_INSTR_PROHIBITED,
- EXCCAUSE_LOAD_PROHIBITED, EXCCAUSE_STORE_PROHIBITED};
- for (i=0; i<(sizeof(exno)/sizeof(exno[0])); i++) {
- _xtos_set_exception_handler(exno[i], gdb_exception_handler);
- }
- }
- #else
- //FreeRTOS doesn't use the Xtensa HAL for exceptions, but uses its own fatal exception handler.
- //We use a small hack to replace that with a jump to our own handler, which then has the task of
- //decyphering and re-instating the registers the FreeRTOS code left.
- extern void user_fatal_exception_handler();
- extern void gdbstub_user_exception_entry();
- static void ATTR_GDBINIT install_exceptions() {
- //Replace the user_fatal_exception_handler by a jump to our own code
- int *ufe=(int*)user_fatal_exception_handler;
- //This mess encodes as a relative jump instruction to user_fatal_exception_handler
- *ufe=((((int)gdbstub_user_exception_entry-(int)user_fatal_exception_handler)-4)<<6)|6;
- }
- #endif
- #if GDBSTUB_CTRLC_BREAK
- #if !GDBSTUB_FREERTOS
- static void ATTR_GDBFN uart_hdlr(void *arg, void *frame) {
- int doDebug=0, fifolen=0;
- //Save the extra registers the Xtensa HAL doesn't save
- gdbstub_save_extra_sfrs_for_exception();
- fifolen=(READ_PERI_REG(UART_STATUS(0))>>UART_RXFIFO_CNT_S)&UART_RXFIFO_CNT;
- while (fifolen!=0) {
- if ((READ_PERI_REG(UART_FIFO(0)) & 0xFF)==0x3) doDebug=1; //Check if any of the chars is control-C. Throw away rest.
- fifolen--;
- }
- WRITE_PERI_REG(UART_INT_CLR(0), UART_RXFIFO_FULL_INT_CLR|UART_RXFIFO_TOUT_INT_CLR);
- if (doDebug) {
- //Copy registers the Xtensa HAL did save to gdbstub_savedRegs
- os_memcpy(&gdbstub_savedRegs, frame, 19*4);
- gdbstub_savedRegs.a1=(uint32_t)frame+EXCEPTION_GDB_SP_OFFSET;
- gdbstub_savedRegs.reason=0xff; //mark as user break reason
- ets_wdt_disable();
- sendReason();
- while(gdbReadCommand()!=ST_CONT);
- ets_wdt_enable();
- //Copy any changed registers back to the frame the Xtensa HAL uses.
- os_memcpy(frame, &gdbstub_savedRegs, 19*4);
- }
- }
- static void ATTR_GDBINIT install_uart_hdlr() {
- ets_isr_attach(ETS_UART_INUM, uart_hdlr, NULL);
- SET_PERI_REG_MASK(UART_INT_ENA(0), UART_RXFIFO_FULL_INT_ENA|UART_RXFIFO_TOUT_INT_ENA);
- ets_isr_unmask((1<<ETS_UART_INUM)); //enable uart interrupt
- }
- #else
- void ATTR_GDBFN gdbstub_handle_uart_int(struct XTensa_rtos_int_frame_s *frame) {
- int doDebug=0, fifolen=0, x;
- fifolen=(READ_PERI_REG(UART_STATUS(0))>>UART_RXFIFO_CNT_S)&UART_RXFIFO_CNT;
- while (fifolen!=0) {
- if ((READ_PERI_REG(UART_FIFO(0)) & 0xFF)==0x3) doDebug=1; //Check if any of the chars is control-C. Throw away rest.
- fifolen--;
- }
- WRITE_PERI_REG(UART_INT_CLR(0), UART_RXFIFO_FULL_INT_CLR|UART_RXFIFO_TOUT_INT_CLR);
- if (doDebug) {
- //Copy registers the Xtensa HAL did save to gdbstub_savedRegs
- gdbstub_savedRegs.pc=frame->pc;
- gdbstub_savedRegs.ps=frame->ps;
- gdbstub_savedRegs.sar=frame->sar;
- gdbstub_savedRegs.a0=frame->a[0];
- gdbstub_savedRegs.a1=frame->a[1];
- for (x=2; x<16; x++) gdbstub_savedRegs.a[x-2]=frame->a[x];
- // gdbstub_savedRegs.a1=(uint32_t)frame+EXCEPTION_GDB_SP_OFFSET;
- gdbstub_savedRegs.reason=0xff; //mark as user break reason
- // ets_wdt_disable();
- sendReason();
- while(gdbReadCommand()!=ST_CONT);
- // ets_wdt_enable();
- //Copy any changed registers back to the frame the Xtensa HAL uses.
- frame->pc=gdbstub_savedRegs.pc;
- frame->ps=gdbstub_savedRegs.ps;
- frame->sar=gdbstub_savedRegs.sar;
- frame->a[0]=gdbstub_savedRegs.a0;
- frame->a[1]=gdbstub_savedRegs.a1;
- for (x=2; x<16; x++) frame->a[x]=gdbstub_savedRegs.a[x-2];
- }
- }
- static void ATTR_GDBINIT install_uart_hdlr() {
- _xt_isr_attach(ETS_UART_INUM, gdbstub_uart_entry);
- SET_PERI_REG_MASK(UART_INT_ENA(0), UART_RXFIFO_FULL_INT_ENA|UART_RXFIFO_TOUT_INT_ENA);
- _xt_isr_unmask((1<<ETS_UART_INUM)); //enable uart interrupt
- }
- #endif
- #endif
- //gdbstub initialization routine.
- void ATTR_GDBINIT gdbstub_init() {
- #if GDBSTUB_REDIRECT_CONSOLE_OUTPUT
- os_install_putc1(gdb_semihost_putchar1);
- #endif
- #if GDBSTUB_CTRLC_BREAK
- install_uart_hdlr();
- #endif
- install_exceptions();
- gdbstub_init_debug_entry();
- #if GDBSTUB_BREAK_ON_INIT
- gdbstub_do_break();
- #endif
- }
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