/* $OpenBSD: db_trace.c,v 1.17 2002/05/18 09:49:17 art Exp $ */
/* $NetBSD: db_trace.c,v 1.20 1997/02/05 05:10:25 scottr Exp $ */
/*
* Mach Operating System
* Copyright (c) 1992 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 Mellon
* the rights to redistribute these changes.
*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <machine/db_machdep.h>
#include <ddb/db_interface.h>
#include <ddb/db_output.h>
#include <ddb/db_access.h>
#include <ddb/db_sym.h>
#include <ddb/db_variables.h>
extern label_t *db_recover;
/*
* Register list
*/
static int db_var_short(struct db_variable *, db_expr_t *, int);
struct db_variable db_regs[] = {
/* D0-D7 */
{ "d0", (long *)&ddb_regs.tf_regs[0], FCN_NULL },
{ "d1", (long *)&ddb_regs.tf_regs[1], FCN_NULL },
{ "d2", (long *)&ddb_regs.tf_regs[2], FCN_NULL },
{ "d3", (long *)&ddb_regs.tf_regs[3], FCN_NULL },
{ "d4", (long *)&ddb_regs.tf_regs[4], FCN_NULL },
{ "d5", (long *)&ddb_regs.tf_regs[5], FCN_NULL },
{ "d6", (long *)&ddb_regs.tf_regs[6], FCN_NULL },
{ "d7", (long *)&ddb_regs.tf_regs[7], FCN_NULL },
/* A0-A7 */
{ "a0", (long *)&ddb_regs.tf_regs[8+0], FCN_NULL },
{ "a1", (long *)&ddb_regs.tf_regs[8+1], FCN_NULL },
{ "a2", (long *)&ddb_regs.tf_regs[8+2], FCN_NULL },
{ "a3", (long *)&ddb_regs.tf_regs[8+3], FCN_NULL },
{ "a4", (long *)&ddb_regs.tf_regs[8+4], FCN_NULL },
{ "a5", (long *)&ddb_regs.tf_regs[8+5], FCN_NULL },
{ "a6", (long *)&ddb_regs.tf_regs[8+6], FCN_NULL },
{ "sp", (long *)&ddb_regs.tf_regs[8+7], FCN_NULL },
/* misc. */
{ "pc", (long *)&ddb_regs.tf_pc, FCN_NULL },
{ "sr", (long *)&ddb_regs.tf_sr, db_var_short }
};
struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
static int
db_var_short(varp, valp, op)
struct db_variable *varp;
db_expr_t *valp;
int op;
{
if (op == DB_VAR_GET)
*valp = (db_expr_t) *((short *)varp->valuep);
else
*((short *)varp->valuep) = (short) *valp;
return(0);
}
#define MAXINT 0x7fffffff
#if 0
#define INKERNEL(va) (((vaddr_t)(va)) >= VM_MIN_KERNEL_ADDRESS && \
(((vaddr_t)(va)) < (USRSTACK - MAXSSIZ) || \
((vaddr_t)(va)) >= USRSTACK))
#else
/* XXX - Slight hack... */
extern int curpcb;
#define INKERNEL(va) (((int)(va) > curpcb) && \
((int)(va) < (curpcb + USPACE)))
#endif
#define get(addr, space) \
(db_get_value((db_addr_t)(addr), sizeof(int), FALSE))
#define get16(addr, space) \
(db_get_value((db_addr_t)(addr), sizeof(u_short), FALSE))
#define NREGISTERS 16
struct stackpos {
int k_pc;
int k_fp;
int k_nargs;
int k_entry;
int k_caller;
int k_flags;
int k_regloc[NREGISTERS];
};
static void findentry(struct stackpos *);
static void findregs(struct stackpos *, db_addr_t);
static int nextframe(struct stackpos *, int);
static void stacktop(db_regs_t *, struct stackpos *);
#define FR_SAVFP 0
#define FR_SAVPC 4
#define K_CALLTRAMP 1 /* for k_flags: caller is __sigtramp */
#define K_SIGTRAMP 2 /* for k_flags: this is __sigtramp */
static void
stacktop(regs, sp)
db_regs_t *regs;
struct stackpos *sp;
{
int i;
/* Note: leave out a6, a7 */
for (i = 0; i < (8+6); i++) {
sp->k_regloc[i] = (int) ®s->tf_regs[i];
}
sp->k_fp = get(®s->tf_regs[8+6], 0);
/* skip sp (a7) */
sp->k_pc = get(®s->tf_pc, 0);
sp->k_flags = 0;
findentry(sp);
}
/*
* The VAX has a very nice calling convention, and it is quite easy to
* find saved registers, and the number of parameters. We are not nearly
* so lucky. We must grub around in code for much of this information
* (remember the PDP-11?), and the saved register list seems to be
* especially hard to find.
*/
#define HIWORD 0xffff0000
#define LOWORD 0x0000ffff
#define LINKLA6 0x480e0000 /* linkl a6,#x */
#define LINKWA6 0x4e560000 /* linkw a6,#x */
#define ADDLSP 0xdffc0000 /* addl #x,sp */
#define ADDWSP 0xdefc0000 /* addw #x,sp */
#define LEASP 0x4fef0000 /* lea sp@(x),sp*/
#define TSTBSP 0x4a2f0000 /* tstb sp@(x) */
#define INSMSK 0xfff80000
#define MOVLSP 0x2e800000 /* movl dx,sp@ */
#define MOVLD0 0x20000000 /* movl d0,dx */
#define MOVLA0 0x20400000 /* movl d0,ax */
#define MVLMSK 0xf1ff0000
#define MOVEML 0x48d70000 /* moveml #x,sp@ */
#define JSR 0x4eb80000 /* jsr x.[WL] */
#define JSRPC 0x4eba0000 /* jsr PC@( ) */
#define LONGBIT 0x00010000
#define BSR 0x61000000 /* bsr x */
#define BSRL 0x61ff0000 /* bsrl x */
#define BYTE3 0x0000ff00
#define LOBYTE 0x000000ff
#define ADQMSK 0xf1ff0000
#define ADDQSP 0x508f0000 /* addql #x,sp */
#define ADDQWSP 0x504f0000 /* addqw #x,sp */
struct nlist * trampsym = 0;
struct nlist * funcsym = 0;
static int
nextframe(sp, kerneltrace)
struct stackpos *sp;
int kerneltrace;
{
int i;
db_addr_t addr;
db_addr_t calladdr;
db_addr_t oldfp = sp->k_fp;
/*
* Find our entry point. Then find out
* which registers we saved, and map them.
* Our entry point is the address our caller called.
*/
calladdr = sp->k_caller;
addr = sp->k_entry;
if (sp->k_flags & K_CALLTRAMP) {
#if 0
/* we never set CALLTRAMP */
/*
* Caller was sigtramp. Therefore:
* - no registers were saved;
* - no new frame-pointer
* - caller found in sigcontext structure.
* - WE become sigtramp
* - we have no parameters
* MUCH MAGIC USED IN FINDING CALLER'S PC.
*/
sp->k_pc = sp->k_caller;
sp->k_entry = trampsym->n_value;
sp->k_flags = 0;
addr = get(sp->k_fp + sizeof(int) * 11, DSP);
sp->k_nargs = 0;
#if DEBUG
db_printf("nextframe: sigcontext at 0x%x, signaled at 0x%x\n",
addr, sp->k_caller);
#endif
errflg = 0;
#endif /* 0 */
} else {
if (addr == MAXINT) {
/* we don't know what registers are involved here--
invalidate all */
for (i = 0; i < NREGISTERS; i++)
sp->k_regloc[i] = -1;
} else
findregs(sp, addr);
/* find caller's pc and fp */
sp->k_pc = calladdr;
sp->k_fp = get(sp->k_fp + FR_SAVFP, DSP);
/*
* Now that we have assumed the identity of our caller, find
* how many longwords of argument WE were called with.
*/
sp->k_flags = 0;
/*
* Don't dig around in user stack to find no. of args and
* entry point if just tracing the kernel
*/
if (kerneltrace && !INKERNEL(sp->k_fp)) {
sp->k_nargs = 0;
sp->k_entry = MAXINT;
} else
findentry(sp);
}
if (sp->k_fp == 0 || oldfp == sp->k_fp)
return 0;
return (sp->k_fp);
}
static void
findentry(sp)
struct stackpos *sp;
{
/*
* Set the k_nargs and k_entry fields in the stackpos structure. This
* is called from stacktop() and from nextframe(). Our caller will do
* an addq or addl or addw to sp just after we return to pop off our
* arguments. Find that instruction and extract the value.
*/
int instruc;
int val;
db_addr_t addr, nextword;
label_t db_jmpbuf;
label_t *savejmp;
savejmp = db_recover;
db_recover = &db_jmpbuf;
if (setjmp(&db_jmpbuf)) {
/* oops -- we touched something we ought not to have */
/* cannot trace caller of "start" */
sp->k_entry = MAXINT;
sp->k_nargs = 0;
db_recover = savejmp;
return;
}
addr = get(sp->k_fp + FR_SAVPC, DSP);
if (addr == 0) {
/* oops -- we touched something we ought not to have */
/* cannot trace caller of "start" */
sp->k_entry = MAXINT;
sp->k_nargs = 0;
db_recover = savejmp;
return;
}
instruc = get(addr - 6, ISP);
nextword = get(addr - 4, ISP);
db_recover = savejmp;
if ((instruc & HIWORD) == (JSR | LONGBIT)) {
/* longword offset here */
sp->k_caller = addr - 6;
sp->k_entry = nextword;
} else if ((instruc & HIWORD) == BSRL) {
/* longword self-relative offset */
sp->k_caller = addr - 6;
sp->k_entry = nextword + (addr - 4);
} else {
instruc = nextword;
if ((instruc & HIWORD) == JSR) {
/* short word offset */
sp->k_caller = addr - 4;
sp->k_entry = instruc & LOWORD;
} else if ((instruc & HIWORD) == BSR) {
/* short word, self-relative offset */
sp->k_caller = addr - 4;
sp->k_entry = (addr - 2) + (short)(instruc & LOWORD);
} else if ((instruc & HIWORD) == JSRPC) {
/* PC-relative, short word offset */
sp->k_caller = addr - 4;
sp->k_entry = (addr - 2) + (instruc & LOWORD);
} else {
if ((instruc & BYTE3) == (BSR >> 16)) {
/* byte, self-relative offset */
sp->k_caller = addr - 2;
sp->k_entry = addr + (char)(instruc & LOBYTE);
} else {
/* was a call through a proc parameter */
sp->k_caller = addr - 2;
sp->k_entry = MAXINT;
/*
* We know that sigtramp calls your signal
* catcher this way -- see if this is the
* tramp: if so then:
* - set the K_CALLTRAMP flag, for use by
* nextframe();
* - take k_entry from __sigfunc array.
*/
#if 0
/* not in kernel */
/*
* The number (9) in the below expression is
* magic: it is the number of stack items below
* callee`s fp and sigtramp`s copy of the
* signal number.
*/
if (trampsym &&
(findsym(sp->k_caller, ISYM), cursym == trampsym)) {
int signl;
sp->k_flags |= K_CALLTRAMP;
if (funcsym) {
signl = get(sp->k_fp + sizeof(int) * 9, DSP);
sp->k_entry = get(funcsym->n_value+(sizeof(int(*)()))*signl, DSP);
} else
sp->k_entry = -1;
errflg = 0;
#ifdef DEBUG
db_printf("Caller is sigtramp: signal is %d: entry is %x\n",
signl, sp->k_entry);
#endif
}
#ifdef DEBUG
else
db_printf("Non-tramp jsr a0@\n");
#endif
#endif /* 0 */
}
}
}
instruc = get(addr, ISP);
/* on bad days, the compiler dumps a register move here */
if ((instruc & MVLMSK) == MOVLA0 ||
(instruc & MVLMSK) == MOVLD0)
instruc = get(addr += 2, ISP);
if ((instruc & ADQMSK) == ADDQSP ||
(instruc & ADQMSK) == ADDQWSP) {
val = 0;
do {
int n;
n = (instruc >> (16+9)) & 07;
if (n == 0)
n = 8;
val += n;
instruc = get(addr += 2, ISP);
} while ((instruc & ADQMSK) == ADDQSP ||
(instruc & ADQMSK) == ADDQWSP);
} else if ((instruc & HIWORD) == ADDLSP)
val = get(addr + 2, ISP);
else if ((instruc & HIWORD) == ADDWSP ||
(instruc & HIWORD) == LEASP)
val = instruc & LOWORD;
else
val = 20;
sp->k_nargs = val / 4;
}
/*
* Look at the procedure prolog of the current called procedure.
* Figure out which registers we saved, and where they are
*/
static void
findregs(sp, addr)
struct stackpos *sp;
db_addr_t addr;
{
long instruc, val, i;
int regp;
regp = 0;
instruc = get(addr, ISP);
if ((instruc & HIWORD) == LINKLA6) {
instruc = get(addr + 2, ISP);
addr += 6;
regp = sp->k_fp + instruc;
} else if ((instruc & HIWORD) == LINKWA6) {
addr += 4;
if ((instruc &= LOWORD) == 0) {
/* look for addl */
instruc = get(addr, ISP);
if ((instruc & HIWORD) == ADDLSP) {
instruc = get(addr + 2, ISP);
addr += 6;
}
/* else frame is really size 0 */
} else {
/* link offset was non-zero -- sign extend it */
instruc <<= 16;
instruc >>= 16;
}
/* we now have the negative frame size */
regp = sp->k_fp + instruc;
}
/* find which registers were saved */
/* (expecting probe instruction next) */
instruc = get(addr, ISP);
if ((instruc & HIWORD) == TSTBSP)
addr += 4;
/* now we expect either a moveml or a movl */
instruc = get(addr, ISP);
if ((instruc & INSMSK) == MOVLSP) {
/* only saving one register */
i = (instruc >> 16) & 07;
sp->k_regloc[i] = regp;
} else if ((instruc & HIWORD) == MOVEML) {
/* saving multiple registers or unoptimized code */
val = instruc & LOWORD;
i = 0;
while (val) {
if (val & 1) {
sp->k_regloc[i] = regp;
regp += sizeof(int);
}
val >>= 1;
i++;
}
}
/* else no registers saved */
}
/*
* Frame tracing.
*/
void
db_stack_trace_print(addr, have_addr, count, modif, pr)
db_expr_t addr;
int have_addr;
db_expr_t count;
char *modif;
int (*pr)(const char *, ...);
{
int i, nargs;
long val;
db_addr_t regp;
char * name;
struct stackpos pos;
boolean_t kernel_only = TRUE;
int fault_pc = 0;
{
char *cp = modif;
char c;
while ((c = *cp++) != 0)
if (c == 'u')
kernel_only = FALSE;
}
if (count == -1)
count = 65535;
if (!have_addr)
stacktop(&ddb_regs, &pos);
#if 0
else {
/*
* Only have user register state.
*/
pcb_t t_pcb;
db_regs_t *user_regs;
t_pcb = (pcb_t) get(&th->pcb, 0);
user_regs = (db_regs_t *)
get(&t_pcb->user_regs, 0);
stacktop(user_regs, &pos);
/* foo*/
}
#endif
else {
pos.k_flags = 0;
pos.k_fp = addr;
pos.k_nargs = 0;
pos.k_pc = MAXINT;
pos.k_entry = MAXINT;
/* sorry, we cannot find our registers without knowing our pc */
for (i = 0; i < NREGISTERS; i++)
pos.k_regloc[i] = 0;
findentry(&pos);
}
while (count) {
count--;
/* HACK */
if (pos.k_pc == MAXINT) {
name = "?";
pos.k_pc = 0;
} else {
db_find_sym_and_offset(pos.k_pc, &name, &val);
if (name == 0) {
val = MAXINT;
name = "?";
}
}
/*
* Since faultstkadj doesn't set up a valid stack frame,
* we would assume it was the source of the fault. To
* get around this we peek at the fourth argument of
* "trap()" (the stack frame at the time of the fault)
* to determine the _real_ value of PC when things wen
* wrong.
*
* NOTE: If the argument list for 'trap()' ever changes,
* we lose.
*/
if (strcmp("_trap", name) == 0) {
int tfp;
/* Point to 'trap()'s 4th argument (frame structure) */
tfp = pos.k_fp + FR_SAVFP + 4 + (4 * 4);
/* Determine if fault was from kernel or user mode */
regp = tfp + offsetof(struct frame, f_sr);
if (!USERMODE(get16(regp, DSP))) {
/*
* Definitely a kernel mode fault,
* so get the PC at the time of the fault.
*/
regp = tfp + offsetof(struct frame, f_pc);
fault_pc = get(regp, DSP);
}
} else
if (fault_pc) {
if (strcmp("faultstkadj", name) == 0) {
db_find_sym_and_offset(fault_pc, &name, &val);
if (name == 0) {
val = MAXINT;
name = "?";
}
}
fault_pc = 0;
}
(*pr)("%s", name);
if (pos.k_entry != MAXINT && name) {
char * entry_name;
long e_val;
db_find_sym_and_offset(pos.k_entry, &entry_name,
&e_val);
if (entry_name != 0 && entry_name != name &&
e_val != val) {
(*pr)("(?)\n%s", entry_name);
}
}
(*pr)("(");
regp = pos.k_fp + FR_SAVFP + 4;
if ((nargs = pos.k_nargs)) {
while (nargs--) {
(*pr)("%lx", get(regp += 4, DSP));
if (nargs)
(*pr)(",");
}
}
if (val == MAXINT)
(*pr)(") at %x\n", pos.k_pc);
else
(*pr)(") + %lx\n", val);
/*
* Stop tracing if frame ptr no longer points into kernel
* stack.
*/
if (kernel_only && !INKERNEL(pos.k_fp))
break;
if (nextframe(&pos, kernel_only) == 0)
break;
}
}
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