text: /*	$OpenBSD: db_trace.c,v 1.7 2010/09/27 10:08:28 mikeb Exp $	*/
  /*	$NetBSD: db_trace.c,v 1.1 2003/04/26 18:39:27 fvdl Exp $	*/
  
  /* 
   * Mach Operating System
   * Copyright (c) 1991,1990 Carnegie Mellon University
   * All Rights Reserved.
   * 
   * Permission to use, copy, modify and distribute this software and its
   * documentation is hereby granted, provided that both the copyright
   * notice and this permission notice appear in all copies of the
   * software, derivative works or modified versions, and any portions
   * thereof, and that both notices appear in supporting documentation.
   * 
   * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
   * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   * 
   * Carnegie Mellon requests users of this software to return to
   * 
   *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   *  School of Computer Science
   *  Carnegie Mellon University
   *  Pittsburgh PA 15213-3890
   * 
   * any improvements or extensions that they make and grant Carnegie the
   * rights to redistribute these changes.
   */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/proc.h>
  #include <sys/user.h> 
  
  #include <machine/db_machdep.h>
  #include <machine/frame.h>
  #include <machine/trap.h>
  
  #include <ddb/db_sym.h>
  #include <ddb/db_access.h>
  #include <ddb/db_variables.h>
  #include <ddb/db_output.h>
  #include <ddb/db_interface.h>
  
  #if 1
  #define dbreg(xx) (long *)offsetof(db_regs_t, tf_ ## xx)
  #else
  #define dbreg(xx) (long *)&ddb_regs.tf_ ## xx
  #endif
  
  static int db_x86_64_regop(struct db_variable *, db_expr_t *, int);
  
  /*
   * Machine register set.
   */
  struct db_variable db_regs[] = {
  	{ "ds",		dbreg(ds),     db_x86_64_regop },
  	{ "es",		dbreg(es),     db_x86_64_regop },
  	{ "fs",		dbreg(fs),     db_x86_64_regop },
  	{ "gs",		dbreg(gs),     db_x86_64_regop },
  	{ "rdi",	dbreg(rdi),    db_x86_64_regop },
  	{ "rsi",	dbreg(rsi),    db_x86_64_regop },
  	{ "rbp",	dbreg(rbp),    db_x86_64_regop },
  	{ "rbx",	dbreg(rbx),    db_x86_64_regop },
  	{ "rdx",	dbreg(rdx),    db_x86_64_regop },
  	{ "rcx",	dbreg(rcx),    db_x86_64_regop },
  	{ "rax",	dbreg(rax),    db_x86_64_regop },
  	{ "r8",		dbreg(r8),     db_x86_64_regop },
  	{ "r9",		dbreg(r9),     db_x86_64_regop },
  	{ "r10",	dbreg(r10),    db_x86_64_regop },
  	{ "r11",	dbreg(r11),    db_x86_64_regop },
  	{ "r12",	dbreg(r12),    db_x86_64_regop },
  	{ "r13",	dbreg(r13),    db_x86_64_regop },
  	{ "r14",	dbreg(r14),    db_x86_64_regop },
  	{ "r15",	dbreg(r15),    db_x86_64_regop },
  	{ "rip",	dbreg(rip),    db_x86_64_regop },
  	{ "cs",		dbreg(cs),     db_x86_64_regop },
  	{ "rflags",	dbreg(rflags), db_x86_64_regop },
  	{ "rsp",	dbreg(rsp),    db_x86_64_regop },
  	{ "ss",		dbreg(ss),     db_x86_64_regop },
  };
  struct db_variable * db_eregs =
  	db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
  
  static int
  db_x86_64_regop(struct db_variable *vp, db_expr_t *val, int opcode)
  {
          db_expr_t *regaddr =
              (db_expr_t *)(((uint8_t *)DDB_REGS) + ((size_t)vp->valuep));
          
          switch (opcode) {
          case DB_VAR_GET:
                  *val = *regaddr;
                  break;
          case DB_VAR_SET:
                  *regaddr = *val;
                  break;
          default:
                  panic("db_x86_64_regop: unknown op %d", opcode);
          }
          return 0;
  }
  
  /*
   * Stack trace.
   */
  #define	INKERNEL(va)	(((vaddr_t)(va)) >= VM_MIN_KERNEL_ADDRESS)
  
  struct x86_64_frame {
  	struct x86_64_frame	*f_frame;
  	long			f_retaddr;
  	long			f_arg0;
  	long			f_arg1;
  };
  
  #define	NONE		0
  #define	TRAP		1
  #define	SYSCALL		2
  #define	INTERRUPT	3
  
  db_addr_t	db_trap_symbol_value = 0;
  db_addr_t	db_syscall_symbol_value = 0;
  db_addr_t	db_kdintr_symbol_value = 0;
  boolean_t	db_trace_symbols_found = FALSE;
  
  void db_find_trace_symbols(void);
  int db_numargs(struct x86_64_frame *);
  void db_nextframe(struct x86_64_frame **, db_addr_t *, long *, int,
      int (*) (const char *, ...));
  
  void
  db_find_trace_symbols(void)
  {
  	db_expr_t	value;
  
  	if (db_value_of_name("_trap", &value))
  		db_trap_symbol_value = (db_addr_t) value;
  	if (db_value_of_name("_kdintr", &value))
  		db_kdintr_symbol_value = (db_addr_t) value;
  	if (db_value_of_name("_syscall", &value))
  		db_syscall_symbol_value = (db_addr_t) value;
  	db_trace_symbols_found = TRUE;
  }
  
  /*
   * Figure out how many arguments were passed into the frame at "fp".
   * We can probably figure out how many arguments where passed above
   * the first 6 (which are in registers), but since we can't
   * reliably determine the values currently, just return 0.
   */
  int
  db_numargs(struct x86_64_frame *fp)
  {
  	return 0;
  }
  
  /* 
   * Figure out the next frame up in the call stack.  
   * For trap(), we print the address of the faulting instruction and 
   *   proceed with the calling frame.  We return the ip that faulted.
   *   If the trap was caused by jumping through a bogus pointer, then
   *   the next line in the backtrace will list some random function as 
   *   being called.  It should get the argument list correct, though.  
   *   It might be possible to dig out from the next frame up the name
   *   of the function that faulted, but that could get hairy.
   */
  void
  db_nextframe(struct x86_64_frame **fp, db_addr_t *ip, long *argp, int is_trap,
      int (*pr)(const char *, ...))
  {
  
  	switch (is_trap) {
  	    case NONE:
  		*ip = (db_addr_t)
  			db_get_value((db_addr_t)&(*fp)->f_retaddr, 8, FALSE);
  		*fp = (struct x86_64_frame *)
  			db_get_value((db_addr_t)&(*fp)->f_frame, 8, FALSE);
  		break;
  
  	    default: {
  		struct trapframe *tf;
  
  		/* The only argument to trap() or syscall() is the trapframe. */
  		tf = (struct trapframe *)argp;
  		switch (is_trap) {
  		case TRAP:
  			(*pr)("--- trap (number %d) ---\n", tf->tf_trapno);
  			break;
  		case SYSCALL:
  			(*pr)("--- syscall (number %ld) ---\n", tf->tf_rax);
  			break;
  		case INTERRUPT:
  			(*pr)("--- interrupt ---\n");
  			break;
  		}
  		*fp = (struct x86_64_frame *)tf->tf_rbp;
  		*ip = (db_addr_t)tf->tf_rip;
  		break;
  	    }
  	}
  }
  
  void
  db_stack_trace_print(db_expr_t addr, boolean_t have_addr, db_expr_t count,
      char *modif, int (*pr)(const char *, ...))
  {
  	struct x86_64_frame *frame, *lastframe;
  	long		*argp;
  	db_addr_t	callpc;
  	int		is_trap = 0;
  	boolean_t	kernel_only = TRUE;
  	boolean_t	trace_proc = FALSE;
  
  #if 0
  	if (!db_trace_symbols_found)
  		db_find_trace_symbols();
  #endif
  
  	{
  		char *cp = modif;
  		char c;
  
  		while ((c = *cp++) != 0) {
  			if (c == 'p')
  				trace_proc = TRUE;
  			if (c == 'u')
  				kernel_only = FALSE;
  		}
  	}
  
  	if (!have_addr) {
  		frame = (struct x86_64_frame *)ddb_regs.tf_rbp;
  		callpc = (db_addr_t)ddb_regs.tf_rip;
  	} else {
  		if (trace_proc) {
  			struct proc *p = pfind((pid_t)addr);
  			if (p == NULL) {
  				(*pr) ("db_trace.c: process not found\n");
  				return;
  			}
  			frame = (struct x86_64_frame *)p->p_addr->u_pcb.pcb_rbp;
  		} else {
  			frame = (struct x86_64_frame *)addr;
  		}
  		callpc = (db_addr_t)
  			 db_get_value((db_addr_t)&frame->f_retaddr, 8, FALSE);
  		frame = (struct x86_64_frame *)frame->f_frame;
  	}
  
  	lastframe = 0;
  	while (count && frame != 0) {
  		int		narg;
  		char *	name;
  		db_expr_t	offset;
  		db_sym_t	sym;
  #define MAXNARG	16
  		char	*argnames[MAXNARG], **argnp = NULL;
  
  		sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
  		db_symbol_values(sym, &name, NULL);
  
  		if (lastframe == 0 && sym == NULL) {
  			/* Symbol not found, peek at code */
  			long	instr = db_get_value(callpc, 8, FALSE);
  
  			offset = 1;
  			if ((instr & 0x00ffffff) == 0x00e58955 ||
  					/* enter: pushl %ebp, movl %esp, %ebp */
  			    (instr & 0x0000ffff) == 0x0000e589
  					/* enter+1: movl %esp, %ebp */) {
  				offset = 0;
  			}
  		}
  		if (INKERNEL(frame) && name) {
  			if (!strcmp(name, "trap")) {
  				is_trap = TRAP;
  			} else if (!strcmp(name, "syscall")) {
  				is_trap = SYSCALL;
  			} else if (name[0] == 'X') {
  				if (!strncmp(name, "Xintr", 5) ||
  				    !strncmp(name, "Xresume", 7) ||
  				    !strncmp(name, "Xstray", 6) ||
  				    !strncmp(name, "Xhold", 5) ||
  				    !strncmp(name, "Xrecurse", 8) ||
  				    !strcmp(name, "Xdoreti") ||
  				    !strncmp(name, "Xsoft", 5)) {
  					is_trap = INTERRUPT;
  				} else
  					goto normal;
  			} else
  				goto normal;
  			narg = 0;
  		} else {
  		normal:
  			is_trap = NONE;
  			narg = MAXNARG;
  			if (db_sym_numargs(sym, &narg, argnames))
  				argnp = argnames;
  			else
  				narg = db_numargs(frame);
  		}
  
  		(*pr)("%s(", name);
  
  		if (lastframe == 0 && offset == 0 && !have_addr) {
  			/*
  			 * We have a breakpoint before the frame is set up
  			 * Use %esp instead
  			 */
  			argp = &((struct x86_64_frame *)(ddb_regs.tf_rsp-8))->f_arg0;
  		} else {
  			argp = &frame->f_arg0;
  		}
  
  		while (narg) {
  			if (argnp)
  				(*pr)("%s=", *argnp++);
  			(*pr)("%lx", db_get_value((db_addr_t)argp, 8, FALSE));
  			argp++;
  			if (--narg != 0)
  				(*pr)(",");
  		}
  		(*pr)(") at ");
  		db_printsym(callpc, DB_STGY_PROC, pr);
  		(*pr)("\n");
  
  		if (lastframe == 0 && offset == 0 && !have_addr) {
  			/* Frame really belongs to next callpc */
  			lastframe = (struct x86_64_frame *)(ddb_regs.tf_rsp-8);
  			callpc = (db_addr_t)
  				 db_get_value((db_addr_t)&lastframe->f_retaddr,
  				    8, FALSE);
  			continue;
  		}
  
  		if (is_trap == INTERRUPT)
  			argp = &lastframe->f_arg1;
  		else
  			argp = &frame->f_arg0;
  		lastframe = frame;
  		db_nextframe(&frame, &callpc, argp, is_trap, pr);
  
  		if (frame == 0) {
  			/* end of chain */
  			break;
  		}
  		if (INKERNEL(frame)) {
  			/* staying in kernel */
  			if (frame <= lastframe) {
  				(*pr)("Bad frame pointer: %p\n", frame);
  				break;
  			}
  		} else if (INKERNEL(lastframe)) {
  			/* switch from user to kernel */
  			if (kernel_only) {
  				(*pr)("end of kernel\n");
  				break;	/* kernel stack only */
  			}
  		} else {
  			/* in user */
  			if (frame <= lastframe) {
  				(*pr)("Bad user frame pointer: %p\n",
  					  frame);
  				break;
  			}
  		}
  		--count;
  	}
  	(*pr)("end trace frame: 0x%lx, count: %d\n", frame, count);
  
  	if (count && is_trap != NONE) {
  		db_printsym(callpc, DB_STGY_XTRN, pr);
  		(*pr)(":\n");
  	}
  }
  