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| Current File : //sys/i386/i386/db_trace.c |
/*-
* 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
* 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/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/i386/i386/db_trace.c 183413 2008-09-27 15:54:04Z kib $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/proc.h>
#include <sys/sysent.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/reg.h>
#include <machine/stack.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <ddb/ddb.h>
#include <ddb/db_access.h>
#include <ddb/db_sym.h>
#include <ddb/db_variables.h>
static db_varfcn_t db_dr0;
static db_varfcn_t db_dr1;
static db_varfcn_t db_dr2;
static db_varfcn_t db_dr3;
static db_varfcn_t db_dr4;
static db_varfcn_t db_dr5;
static db_varfcn_t db_dr6;
static db_varfcn_t db_dr7;
static db_varfcn_t db_esp;
static db_varfcn_t db_frame;
static db_varfcn_t db_ss;
/*
* Machine register set.
*/
#define DB_OFFSET(x) (db_expr_t *)offsetof(struct trapframe, x)
struct db_variable db_regs[] = {
{ "cs", DB_OFFSET(tf_cs), db_frame },
{ "ds", DB_OFFSET(tf_ds), db_frame },
{ "es", DB_OFFSET(tf_es), db_frame },
{ "fs", DB_OFFSET(tf_fs), db_frame },
{ "ss", NULL, db_ss },
{ "eax", DB_OFFSET(tf_eax), db_frame },
{ "ecx", DB_OFFSET(tf_ecx), db_frame },
{ "edx", DB_OFFSET(tf_edx), db_frame },
{ "ebx", DB_OFFSET(tf_ebx), db_frame },
{ "esp", NULL, db_esp },
{ "ebp", DB_OFFSET(tf_ebp), db_frame },
{ "esi", DB_OFFSET(tf_esi), db_frame },
{ "edi", DB_OFFSET(tf_edi), db_frame },
{ "eip", DB_OFFSET(tf_eip), db_frame },
{ "efl", DB_OFFSET(tf_eflags), db_frame },
#define DB_N_SHOW_REGS 15 /* Don't show registers after here. */
{ "dr0", NULL, db_dr0 },
{ "dr1", NULL, db_dr1 },
{ "dr2", NULL, db_dr2 },
{ "dr3", NULL, db_dr3 },
{ "dr4", NULL, db_dr4 },
{ "dr5", NULL, db_dr5 },
{ "dr6", NULL, db_dr6 },
{ "dr7", NULL, db_dr7 },
};
struct db_variable *db_eregs = db_regs + DB_N_SHOW_REGS;
#define DB_DRX_FUNC(reg) \
static int \
db_ ## reg (vp, valuep, op) \
struct db_variable *vp; \
db_expr_t * valuep; \
int op; \
{ \
if (op == DB_VAR_GET) \
*valuep = r ## reg (); \
else \
load_ ## reg (*valuep); \
return (1); \
}
DB_DRX_FUNC(dr0)
DB_DRX_FUNC(dr1)
DB_DRX_FUNC(dr2)
DB_DRX_FUNC(dr3)
DB_DRX_FUNC(dr4)
DB_DRX_FUNC(dr5)
DB_DRX_FUNC(dr6)
DB_DRX_FUNC(dr7)
static __inline int
get_esp(struct trapframe *tf)
{
return ((ISPL(tf->tf_cs)) ? tf->tf_esp :
(db_expr_t)tf + (uintptr_t)DB_OFFSET(tf_esp));
}
static int
db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
{
int *reg;
if (kdb_frame == NULL)
return (0);
reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
if (op == DB_VAR_GET)
*valuep = *reg;
else
*reg = *valuep;
return (1);
}
static int
db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
{
if (kdb_frame == NULL)
return (0);
if (op == DB_VAR_GET)
*valuep = get_esp(kdb_frame);
else if (ISPL(kdb_frame->tf_cs))
kdb_frame->tf_esp = *valuep;
return (1);
}
static int
db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
{
if (kdb_frame == NULL)
return (0);
if (op == DB_VAR_GET)
*valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss();
else if (ISPL(kdb_frame->tf_cs))
kdb_frame->tf_ss = *valuep;
return (1);
}
#define NORMAL 0
#define TRAP 1
#define INTERRUPT 2
#define SYSCALL 3
#define DOUBLE_FAULT 4
#define TRAP_INTERRUPT 5
#define TRAP_TIMERINT 6
static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
static int db_numargs(struct i386_frame *);
static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t);
static void decode_syscall(int, struct thread *);
static const char * watchtype_str(int type);
int i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
struct dbreg *d);
int i386_clr_watch(int watchnum, struct dbreg *d);
/*
* Figure out how many arguments were passed into the frame at "fp".
*/
static int
db_numargs(fp)
struct i386_frame *fp;
{
char *argp;
int inst;
int args;
argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
/*
* XXX etext is wrong for LKMs. We should attempt to interpret
* the instruction at the return address in all cases. This
* may require better fault handling.
*/
if (argp < btext || argp >= etext) {
args = -1;
} else {
retry:
inst = db_get_value((int)argp, 4, FALSE);
if ((inst & 0xff) == 0x59) /* popl %ecx */
args = 1;
else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
args = ((inst >> 16) & 0xff) / 4;
else if ((inst & 0xf8ff) == 0xc089) { /* movl %eax, %Reg */
argp += 2;
goto retry;
} else
args = -1;
}
return (args);
}
static void
db_print_stack_entry(name, narg, argnp, argp, callpc)
const char *name;
int narg;
char **argnp;
int *argp;
db_addr_t callpc;
{
int n = narg >= 0 ? narg : 5;
db_printf("%s(", name);
while (n) {
if (argnp)
db_printf("%s=", *argnp++);
db_printf("%r", db_get_value((int)argp, 4, FALSE));
argp++;
if (--n != 0)
db_printf(",");
}
if (narg < 0)
db_printf(",...");
db_printf(") at ");
db_printsym(callpc, DB_STGY_PROC);
db_printf("\n");
}
static void
decode_syscall(int number, struct thread *td)
{
struct proc *p;
c_db_sym_t sym;
db_expr_t diff;
sy_call_t *f;
const char *symname;
db_printf(" (%d", number);
p = (td != NULL) ? td->td_proc : NULL;
if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
f = p->p_sysent->sv_table[number].sy_call;
sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
if (sym != DB_SYM_NULL && diff == 0) {
db_symbol_values(sym, &symname, NULL);
db_printf(", %s, %s", p->p_sysent->sv_name, symname);
}
}
db_printf(")");
}
/*
* Figure out the next frame up in the call stack.
*/
static void
db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
{
struct trapframe *tf;
int frame_type;
int eip, esp, ebp;
db_expr_t offset;
c_db_sym_t sym;
const char *name;
eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
/*
* Figure out frame type. We look at the address just before
* the saved instruction pointer as the saved EIP is after the
* call function, and if the function being called is marked as
* dead (such as panic() at the end of dblfault_handler()), then
* the instruction at the saved EIP will be part of a different
* function (syscall() in this example) rather than the one that
* actually made the call.
*/
frame_type = NORMAL;
sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
db_symbol_values(sym, &name, NULL);
if (name != NULL) {
if (strcmp(name, "calltrap") == 0 ||
strcmp(name, "fork_trampoline") == 0)
frame_type = TRAP;
else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
strncmp(name, "Xapic_isr", 9) == 0)
frame_type = INTERRUPT;
else if (strcmp(name, "Xlcall_syscall") == 0 ||
strcmp(name, "Xint0x80_syscall") == 0)
frame_type = SYSCALL;
else if (strcmp(name, "dblfault_handler") == 0)
frame_type = DOUBLE_FAULT;
/* XXX: These are interrupts with trap frames. */
else if (strcmp(name, "Xtimerint") == 0)
frame_type = TRAP_TIMERINT;
else if (strcmp(name, "Xcpustop") == 0 ||
strcmp(name, "Xrendezvous") == 0 ||
strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
strcmp(name, "Xlazypmap") == 0)
frame_type = TRAP_INTERRUPT;
}
/*
* Normal frames need no special processing.
*/
if (frame_type == NORMAL) {
*ip = (db_addr_t) eip;
*fp = (struct i386_frame *) ebp;
return;
}
db_print_stack_entry(name, 0, 0, 0, eip);
/*
* For a double fault, we have to snag the values from the
* previous TSS since a double fault uses a task gate to
* switch to a known good state.
*/
if (frame_type == DOUBLE_FAULT) {
esp = PCPU_GET(common_tss.tss_esp);
eip = PCPU_GET(common_tss.tss_eip);
ebp = PCPU_GET(common_tss.tss_ebp);
db_printf(
"--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
eip, esp, ebp);
*ip = (db_addr_t) eip;
*fp = (struct i386_frame *) ebp;
return;
}
/*
* Point to base of trapframe which is just above the
* current frame.
*/
if (frame_type == INTERRUPT)
tf = (struct trapframe *)((int)*fp + 16);
else if (frame_type == TRAP_INTERRUPT)
tf = (struct trapframe *)((int)*fp + 8);
else
tf = (struct trapframe *)((int)*fp + 12);
if (INKERNEL((int) tf)) {
esp = get_esp(tf);
eip = tf->tf_eip;
ebp = tf->tf_ebp;
switch (frame_type) {
case TRAP:
db_printf("--- trap %#r", tf->tf_trapno);
break;
case SYSCALL:
db_printf("--- syscall");
decode_syscall(tf->tf_eax, td);
break;
case TRAP_TIMERINT:
case TRAP_INTERRUPT:
case INTERRUPT:
db_printf("--- interrupt");
break;
default:
panic("The moon has moved again.");
}
db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
esp, ebp);
}
*ip = (db_addr_t) eip;
*fp = (struct i386_frame *) ebp;
}
static int
db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
db_addr_t pc, int count)
{
struct i386_frame *actframe;
#define MAXNARG 16
char *argnames[MAXNARG], **argnp = NULL;
const char *name;
int *argp;
db_expr_t offset;
c_db_sym_t sym;
int instr, narg;
boolean_t first;
/*
* If an indirect call via an invalid pointer caused a trap,
* %pc contains the invalid address while the return address
* of the unlucky caller has been saved by CPU on the stack
* just before the trap frame. In this case, try to recover
* the caller's address so that the first frame is assigned
* to the right spot in the right function, for that is where
* the failure actually happened.
*
* This trick depends on the fault address stashed in tf_err
* by trap_fatal() before entering KDB.
*/
if (kdb_frame && pc == kdb_frame->tf_err) {
/*
* Find where the trap frame actually ends.
* It won't contain tf_esp or tf_ss unless crossing rings.
*/
if (ISPL(kdb_frame->tf_cs))
instr = (int)(kdb_frame + 1);
else
instr = (int)&kdb_frame->tf_esp;
pc = db_get_value(instr, 4, FALSE);
}
if (count == -1)
count = 1024;
first = TRUE;
while (count-- && !db_pager_quit) {
sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
db_symbol_values(sym, &name, NULL);
/*
* Attempt to determine a (possibly fake) frame that gives
* the caller's pc. It may differ from `frame' if the
* current function never sets up a standard frame or hasn't
* set one up yet or has just discarded one. The last two
* cases can be guessed fairly reliably for code generated
* by gcc. The first case is too much trouble to handle in
* general because the amount of junk on the stack depends
* on the pc (the special handling of "calltrap", etc. in
* db_nextframe() works because the `next' pc is special).
*/
actframe = frame;
if (first) {
if (tf != NULL) {
instr = db_get_value(pc, 4, FALSE);
if ((instr & 0xffffff) == 0x00e58955) {
/* pushl %ebp; movl %esp, %ebp */
actframe = (void *)(get_esp(tf) - 4);
} else if ((instr & 0xffff) == 0x0000e589) {
/* movl %esp, %ebp */
actframe = (void *)get_esp(tf);
if (tf->tf_ebp == 0) {
/* Fake frame better. */
frame = actframe;
}
} else if ((instr & 0xff) == 0x000000c3) {
/* ret */
actframe = (void *)(get_esp(tf) - 4);
} else if (offset == 0) {
/* Probably an assembler symbol. */
actframe = (void *)(get_esp(tf) - 4);
}
} else if (strcmp(name, "fork_trampoline") == 0) {
/*
* Don't try to walk back on a stack for a
* process that hasn't actually been run yet.
*/
db_print_stack_entry(name, 0, 0, 0, pc);
break;
}
first = FALSE;
}
argp = &actframe->f_arg0;
narg = MAXNARG;
if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
argnp = argnames;
} else {
narg = db_numargs(frame);
}
db_print_stack_entry(name, narg, argnp, argp, pc);
if (actframe != frame) {
/* `frame' belongs to caller. */
pc = (db_addr_t)
db_get_value((int)&actframe->f_retaddr, 4, FALSE);
continue;
}
db_nextframe(&frame, &pc, td);
if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
db_symbol_values(sym, &name, NULL);
db_print_stack_entry(name, 0, 0, 0, pc);
break;
}
if (!INKERNEL((int) frame)) {
break;
}
}
return (0);
}
void
db_trace_self(void)
{
struct i386_frame *frame;
db_addr_t callpc;
register_t ebp;
__asm __volatile("movl %%ebp,%0" : "=r" (ebp));
frame = (struct i386_frame *)ebp;
callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
frame = frame->f_frame;
db_backtrace(curthread, NULL, frame, callpc, -1);
}
int
db_trace_thread(struct thread *thr, int count)
{
struct pcb *ctx;
ctx = kdb_thr_ctx(thr);
return (db_backtrace(thr, NULL, (struct i386_frame *)ctx->pcb_ebp,
ctx->pcb_eip, count));
}
int
i386_set_watch(watchnum, watchaddr, size, access, d)
int watchnum;
unsigned int watchaddr;
int size;
int access;
struct dbreg *d;
{
int i, len;
if (watchnum == -1) {
for (i = 0; i < 4; i++)
if (!DBREG_DR7_ENABLED(d->dr[7], i))
break;
if (i < 4)
watchnum = i;
else
return (-1);
}
switch (access) {
case DBREG_DR7_EXEC:
size = 1; /* size must be 1 for an execution breakpoint */
/* fall through */
case DBREG_DR7_WRONLY:
case DBREG_DR7_RDWR:
break;
default:
return (-1);
}
/*
* we can watch a 1, 2, or 4 byte sized location
*/
switch (size) {
case 1:
len = DBREG_DR7_LEN_1;
break;
case 2:
len = DBREG_DR7_LEN_2;
break;
case 4:
len = DBREG_DR7_LEN_4;
break;
default:
return (-1);
}
/* clear the bits we are about to affect */
d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
/* set drN register to the address, N=watchnum */
DBREG_DRX(d, watchnum) = watchaddr;
/* enable the watchpoint */
d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
DBREG_DR7_GLOBAL_ENABLE);
return (watchnum);
}
int
i386_clr_watch(watchnum, d)
int watchnum;
struct dbreg *d;
{
if (watchnum < 0 || watchnum >= 4)
return (-1);
d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
DBREG_DRX(d, watchnum) = 0;
return (0);
}
int
db_md_set_watchpoint(addr, size)
db_expr_t addr;
db_expr_t size;
{
struct dbreg d;
int avail, i, wsize;
fill_dbregs(NULL, &d);
avail = 0;
for(i = 0; i < 4; i++) {
if (!DBREG_DR7_ENABLED(d.dr[7], i))
avail++;
}
if (avail * 4 < size)
return (-1);
for (i = 0; i < 4 && (size > 0); i++) {
if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
if (size > 2)
wsize = 4;
else
wsize = size;
i386_set_watch(i, addr, wsize,
DBREG_DR7_WRONLY, &d);
addr += wsize;
size -= wsize;
}
}
set_dbregs(NULL, &d);
return(0);
}
int
db_md_clr_watchpoint(addr, size)
db_expr_t addr;
db_expr_t size;
{
struct dbreg d;
int i;
fill_dbregs(NULL, &d);
for(i = 0; i < 4; i++) {
if (DBREG_DR7_ENABLED(d.dr[7], i)) {
if ((DBREG_DRX((&d), i) >= addr) &&
(DBREG_DRX((&d), i) < addr+size))
i386_clr_watch(i, &d);
}
}
set_dbregs(NULL, &d);
return(0);
}
static const char *
watchtype_str(type)
int type;
{
switch (type) {
case DBREG_DR7_EXEC : return "execute"; break;
case DBREG_DR7_RDWR : return "read/write"; break;
case DBREG_DR7_WRONLY : return "write"; break;
default : return "invalid"; break;
}
}
void
db_md_list_watchpoints()
{
struct dbreg d;
int i, len, type;
fill_dbregs(NULL, &d);
db_printf("\nhardware watchpoints:\n");
db_printf(" watch status type len address\n");
db_printf(" ----- -------- ---------- --- ----------\n");
for (i = 0; i < 4; i++) {
if (DBREG_DR7_ENABLED(d.dr[7], i)) {
type = DBREG_DR7_ACCESS(d.dr[7], i);
len = DBREG_DR7_LEN(d.dr[7], i);
db_printf(" %-5d %-8s %10s %3d ",
i, "enabled", watchtype_str(type), len + 1);
db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
db_printf("\n");
} else {
db_printf(" %-5d disabled\n", i);
}
}
db_printf("\ndebug register values:\n");
for (i = 0; i < 8; i++) {
db_printf(" dr%d 0x%08x\n", i, DBREG_DRX((&d), i));
}
db_printf("\n");
}