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-rw-r--r--share/man/man4/ddb.481
-rw-r--r--sys/amd64/amd64/trap.c38
-rw-r--r--sys/amd64/include/db_machdep.h12
-rw-r--r--sys/ddb/db_examine.c2
-rw-r--r--sys/ddb/db_expr.c36
-rw-r--r--sys/ddb/db_main.c5
-rw-r--r--sys/ddb/db_run.c40
-rw-r--r--sys/ddb/ddb.h3
-rw-r--r--sys/i386/i386/db_disasm.c13
-rw-r--r--sys/i386/i386/db_interface.c24
-rw-r--r--sys/i386/i386/db_trace.c55
-rw-r--r--sys/i386/i386/trap.c41
-rw-r--r--sys/i386/i386/vm86.c8
-rw-r--r--sys/i386/include/db_machdep.h19
-rw-r--r--sys/x86/include/frame.h16
15 files changed, 274 insertions, 119 deletions
diff --git a/share/man/man4/ddb.4 b/share/man/man4/ddb.4
index 010ab00..6b072ba 100644
--- a/share/man/man4/ddb.4
+++ b/share/man/man4/ddb.4
@@ -146,25 +146,32 @@ to be the same as
.Pp
The general command syntax is:
.Ar command Ns Op Li / Ns Ar modifier
-.Ar address Ns Op Li , Ns Ar count
+.Oo Ar addr Oc Ns Op Li , Ns Ar count
.Pp
A blank line repeats the previous command from the address
.Va next
with
count 1 and no modifiers.
Specifying
-.Ar address
+.Ar addr
sets
.Va dot
to the address.
Omitting
-.Ar address
+.Ar addr
uses
.Va dot .
A missing
.Ar count
is taken
to be 1 for printing commands or infinity for stack traces.
+A
+.Ar count
+of -1 is equivalent to a missing
+.Ar count .
+Options that are supplied but not supported by the given
+.Ar command
+are usually ignored.
.Pp
The
.Nm
@@ -204,8 +211,14 @@ browse through the history buffer, and move the cursor within the
current line.
.Sh COMMANDS
.Bl -tag -width indent -compact
-.It Ic examine
-.It Ic x
+.It Xo
+.Ic examine Ns Op Li / Ns Cm AISabcdghilmorsuxz ...
+.Oo Ar addr Oc Ns Op Li , Ns Ar count
+.Xc
+.It Xo
+.Ic x Ns Op Li / Ns Cm AISabcdghilmorsuxz ...
+.Oo Ar addr Oc Ns Op Li , Ns Ar count
+.Xc
Display the addressed locations according to the formats in the modifier.
Multiple modifier formats display multiple locations.
If no format is specified, the last format specified for this command
@@ -251,7 +264,9 @@ The location is also displayed in hex at the beginning of each line.
display as an instruction
.It Cm I
display as an instruction with possible alternate formats depending on the
-machine, but none of the supported architectures have an alternate format.
+machine.
+On i386, this selects the alternate format for the instruction decoding
+(16 bits in a 32-bit code segment and vice versa).
.It Cm S
display a symbol name for the pointer stored at the address
.El
@@ -328,16 +343,17 @@ Set the named variable or register with the value of
.Ar expr .
Valid variable names are described below.
.Pp
-.It Ic break Ns Op Li / Ns Cm u
-.It Ic b Ns Op Li / Ns Cm u
+.It Ic break Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op Li , Ns Ar count
+.It Ic b Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op Li , Ns Ar count
Set a break point at
.Ar addr .
If
.Ar count
-is supplied, continues
+is supplied, the
+.Ic continue
+command will not stop at this break point on the first
.Ar count
-\- 1 times before stopping at the
-break point.
+\- 1 times that it is hit.
If the break point is set, a break point number is
printed with
.Ql # .
@@ -361,21 +377,24 @@ user space break points may not work correctly.
Setting a break
point at the low-level code paths may also cause strange behavior.
.Pp
-.It Ic delete Ar addr
-.It Ic d Ar addr
+.It Ic delete Op Ar addr
+.It Ic d Op Ar addr
.It Ic delete Li # Ns Ar number
-.It Ic d Li # Ns Ar number
-Delete the break point.
-The target break point can be specified by a
+.It Ic d Li # Ns Ar number
+Delete the specified break point.
+The break point can be specified by a
break point number with
.Ql # ,
or by using the same
.Ar addr
specified in the original
.Ic break
-command.
+command, or by omitting
+.Ar addr
+to get the default address of
+.Va dot .
.Pp
-.It Ic watch Ar addr Ns Li , Ns Ar size
+.It Ic watch Oo Ar addr Oc Ns Op Li , Ns Ar size
Set a watchpoint for a region.
Execution stops when an attempt to modify the region occurs.
The
@@ -389,7 +408,7 @@ Attempts to watch wired kernel memory
may cause unrecoverable error in some systems such as i386.
Watchpoints on user addresses work best.
.Pp
-.It Ic hwatch Ar addr Ns Li , Ns Ar size
+.It Ic hwatch Oo Ar addr Oc Ns Op Li , Ns Ar size
Set a hardware watchpoint for a region if supported by the
architecture.
Execution stops when an attempt to modify the region occurs.
@@ -405,14 +424,14 @@ Use
for setting watchpoints on kernel address locations only, and avoid
its use on user mode address spaces.
.Pp
-.It Ic dhwatch Ar addr Ns Li , Ns Ar size
+.It Ic dhwatch Oo Ar addr Oc Ns Op Li , Ns Ar size
Delete specified hardware watchpoint.
.Pp
-.It Ic step Ns Op Li / Ns Cm p
-.It Ic s Ns Op Li / Ns Cm p
+.It Ic step Ns Oo Li / Ns Cm p Oc Ns Op Li , Ns Ar count
+.It Ic s Ns Oo Li / Ns Cm p Oc Ns Op Li , Ns Ar count
Single step
.Ar count
-times (the comma is a mandatory part of the syntax).
+times.
If the
.Cm p
modifier is specified, print each instruction at each step.
@@ -458,22 +477,22 @@ Otherwise, only print when the matching return is hit.
.Pp
.It Xo
.Ic trace Ns Op Li / Ns Cm u
-.Op Ar pid | tid
+.Op Ar pid | tid Ns
.Op Li , Ns Ar count
.Xc
.It Xo
.Ic t Ns Op Li / Ns Cm u
-.Op Ar pid | tid
+.Op Ar pid | tid Ns
.Op Li , Ns Ar count
.Xc
.It Xo
.Ic where Ns Op Li / Ns Cm u
-.Op Ar pid | tid
+.Op Ar pid | tid Ns
.Op Li , Ns Ar count
.Xc
.It Xo
.Ic bt Ns Op Li / Ns Cm u
-.Op Ar pid | tid
+.Op Ar pid | tid Ns
.Op Li , Ns Ar count
.Xc
Stack trace.
@@ -498,16 +517,11 @@ only if the machine dependent code supports it.
.Ic search Ns Op Li / Ns Cm bhl
.Ar addr
.Ar value
-.Op Ar mask
+.Op Ar mask Ns
.Op Li , Ns Ar count
.Xc
Search memory for
.Ar value .
-This command might fail in interesting
-ways if it does not find the searched-for value.
-This is because
-.Nm
-does not always recover from touching bad memory.
The optional
.Ar count
argument limits the search.
@@ -537,7 +551,6 @@ addresses for the process and not show other information.
.Pp
.It Ic show Cm all trace
.It Ic alltrace
-.Xc
Show a stack trace for every thread in the system.
.Pp
.It Ic show Cm all ttys
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 04c5dcc..8d2b399 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -176,7 +176,10 @@ trap(struct trapframe *frame)
#endif
struct thread *td = curthread;
struct proc *p = td->td_proc;
- int i = 0, ucode = 0, code;
+#ifdef KDB
+ register_t dr6;
+#endif
+ int i = 0, ucode = 0;
u_int type;
register_t addr = 0;
ksiginfo_t ksi;
@@ -236,7 +239,7 @@ trap(struct trapframe *frame)
* interrupts disabled until they are accidentally
* enabled later.
*/
- if (ISPL(frame->tf_cs) == SEL_UPL)
+ if (TRAPF_USERMODE(frame))
uprintf(
"pid %ld (%s): trap %d with interrupts disabled\n",
(long)curproc->p_pid, curthread->td_name, type);
@@ -258,9 +261,7 @@ trap(struct trapframe *frame)
}
}
- code = frame->tf_err;
-
- if (ISPL(frame->tf_cs) == SEL_UPL) {
+ if (TRAPF_USERMODE(frame)) {
/* user trap */
td->td_pticks = 0;
@@ -377,7 +378,7 @@ trap(struct trapframe *frame)
#ifdef DEV_ISA
case T_NMI:
/* machine/parity/power fail/"kitchen sink" faults */
- if (isa_nmi(code) == 0) {
+ if (isa_nmi(frame->tf_err) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
@@ -540,8 +541,7 @@ trap(struct trapframe *frame)
* Reset breakpoint bits because the
* processor doesn't
*/
- /* XXX check upper bits here */
- load_dr6(rdr6() & 0xfffffff0);
+ load_dr6(rdr6() & ~0xf);
goto out;
}
/*
@@ -553,7 +553,10 @@ trap(struct trapframe *frame)
* Otherwise, debugger traps "can't happen".
*/
#ifdef KDB
- if (kdb_trap(type, 0, frame))
+ /* XXX %dr6 is not quite reentrant. */
+ dr6 = rdr6();
+ load_dr6(dr6 & ~0x4000);
+ if (kdb_trap(type, dr6, frame))
goto out;
#endif
break;
@@ -561,7 +564,7 @@ trap(struct trapframe *frame)
#ifdef DEV_ISA
case T_NMI:
/* machine/parity/power fail/"kitchen sink" faults */
- if (isa_nmi(code) == 0) {
+ if (isa_nmi(frame->tf_err) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
@@ -773,7 +776,6 @@ trap_fatal(frame, eva)
{
int code, ss;
u_int type;
- long esp;
struct soft_segment_descriptor softseg;
char *msg;
@@ -787,7 +789,7 @@ trap_fatal(frame, eva)
else
msg = "UNKNOWN";
printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
- ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
+ TRAPF_USERMODE(frame) ? "user" : "kernel");
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
@@ -804,14 +806,8 @@ trap_fatal(frame, eva)
}
printf("instruction pointer = 0x%lx:0x%lx\n",
frame->tf_cs & 0xffff, frame->tf_rip);
- if (ISPL(frame->tf_cs) == SEL_UPL) {
- ss = frame->tf_ss & 0xffff;
- esp = frame->tf_rsp;
- } else {
- ss = GSEL(GDATA_SEL, SEL_KPL);
- esp = (long)&frame->tf_rsp;
- }
- printf("stack pointer = 0x%x:0x%lx\n", ss, esp);
+ ss = frame->tf_ss & 0xffff;
+ printf("stack pointer = 0x%x:0x%lx\n", ss, frame->tf_rsp);
printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
@@ -934,7 +930,7 @@ amd64_syscall(struct thread *td, int traced)
ksiginfo_t ksi;
#ifdef DIAGNOSTIC
- if (ISPL(td->td_frame->tf_cs) != SEL_UPL) {
+ if (!TRAPF_USERMODE(td->td_frame)) {
panic("syscall");
/* NOT REACHED */
}
diff --git a/sys/amd64/include/db_machdep.h b/sys/amd64/include/db_machdep.h
index 29e385e..722a7b3 100644
--- a/sys/amd64/include/db_machdep.h
+++ b/sys/amd64/include/db_machdep.h
@@ -56,12 +56,16 @@ do { \
#define db_clear_single_step kdb_cpu_clear_singlestep
#define db_set_single_step kdb_cpu_set_singlestep
-#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
/*
- * Watchpoints are not supported. The debug exception type is in %dr6
- * and not yet in the args to this macro.
+ * The debug exception type is copied from %dr6 to 'code' and used to
+ * disambiguate single step traps. Watchpoints have no special support.
+ * Our hardware breakpoints are not well integrated with ddb and are too
+ * different from watchpoints. ddb treats them as unknown traps with
+ * unknown addresses and doesn't turn them off while it is running.
*/
-#define IS_WATCHPOINT_TRAP(type, code) 0
+#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
+#define IS_SSTEP_TRAP(type, code) ((type) == T_TRCTRAP && (code) & 0x4000)
+#define IS_WATCHPOINT_TRAP(type, code) 0
#define I_CALL 0xe8
#define I_CALLI 0xff
diff --git a/sys/ddb/db_examine.c b/sys/ddb/db_examine.c
index de2bbe4..a1e5a28 100644
--- a/sys/ddb/db_examine.c
+++ b/sys/ddb/db_examine.c
@@ -241,7 +241,7 @@ db_print_loc_and_inst(db_addr_t loc)
db_printsym(loc, DB_STGY_PROC);
if (db_search_symbol(loc, DB_STGY_PROC, &off) != C_DB_SYM_NULL) {
db_printf(":\t");
- (void)db_disasm(loc, true);
+ (void)db_disasm(loc, false);
}
}
diff --git a/sys/ddb/db_expr.c b/sys/ddb/db_expr.c
index db17f36..c206a57 100644
--- a/sys/ddb/db_expr.c
+++ b/sys/ddb/db_expr.c
@@ -57,7 +57,8 @@ db_term(db_expr_t *valuep)
if (!db_value_of_name(db_tok_string, valuep) &&
!db_value_of_name_pcpu(db_tok_string, valuep) &&
!db_value_of_name_vnet(db_tok_string, valuep)) {
- db_error("Symbol not found\n");
+ db_printf("Symbol '%s' not found\n", db_tok_string);
+ db_error(NULL);
/*NOTREACHED*/
}
return (true);
@@ -89,12 +90,14 @@ db_term(db_expr_t *valuep)
}
if (t == tLPAREN) {
if (!db_expression(valuep)) {
- db_error("Syntax error\n");
+ db_printf("Expression syntax error after '%c'\n", '(');
+ db_error(NULL);
/*NOTREACHED*/
}
t = db_read_token();
if (t != tRPAREN) {
- db_error("Syntax error\n");
+ db_printf("Expression syntax error -- expected '%c'\n", ')');
+ db_error(NULL);
/*NOTREACHED*/
}
return (true);
@@ -164,7 +167,9 @@ db_mult_expr(db_expr_t *valuep)
while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH ||
t == tBIT_AND ) {
if (!db_term(&rhs)) {
- db_printf("Expression syntax error after '%c'\n", '!');
+ db_printf("Expression syntax error after '%c'\n",
+ t == tSTAR ? '*' : t == tSLASH ? '/' : t == tPCT ? '%' :
+ t == tHASH ? '#' : '&');
db_error(NULL);
/*NOTREACHED*/
}
@@ -177,7 +182,7 @@ db_mult_expr(db_expr_t *valuep)
break;
default:
if (rhs == 0) {
- db_error("Divide by 0\n");
+ db_error("Division by 0\n");
/*NOTREACHED*/
}
if (t == tSLASH)
@@ -199,7 +204,6 @@ db_add_expr(db_expr_t *valuep)
{
db_expr_t lhs, rhs;
int t;
- char c;
if (!db_mult_expr(&lhs))
return (false);
@@ -207,8 +211,8 @@ db_add_expr(db_expr_t *valuep)
t = db_read_token();
while (t == tPLUS || t == tMINUS || t == tBIT_OR) {
if (!db_mult_expr(&rhs)) {
- c = db_tok_string[0];
- db_printf("Expression syntax error after '%c'\n", c);
+ db_printf("Expression syntax error after '%c'\n",
+ t == tPLUS ? '+' : t == tMINUS ? '-' : '|');
db_error(NULL);
/*NOTREACHED*/
}
@@ -243,11 +247,14 @@ db_shift_expr(db_expr_t *valuep)
t = db_read_token();
while (t == tSHIFT_L || t == tSHIFT_R) {
if (!db_add_expr(&rhs)) {
- db_error("Syntax error\n");
+ db_printf("Expression syntax error after '%s'\n",
+ t == tSHIFT_L ? "<<" : ">>");
+ db_error(NULL);
/*NOTREACHED*/
}
if (rhs < 0) {
- db_error("Negative shift amount\n");
+ db_printf("Negative shift amount %jd\n", (intmax_t)rhs);
+ db_error(NULL);
/*NOTREACHED*/
}
if (t == tSHIFT_L)
@@ -269,7 +276,6 @@ db_logical_relation_expr(
{
db_expr_t lhs, rhs;
int t;
- char op[3];
if (!db_shift_expr(&lhs))
return (false);
@@ -277,11 +283,11 @@ db_logical_relation_expr(
t = db_read_token();
while (t == tLOG_EQ || t == tLOG_NOT_EQ || t == tGREATER ||
t == tGREATER_EQ || t == tLESS || t == tLESS_EQ) {
- op[0] = db_tok_string[0];
- op[1] = db_tok_string[1];
- op[2] = 0;
if (!db_shift_expr(&rhs)) {
- db_printf("Expression syntax error after \"%s\"\n", op);
+ db_printf("Expression syntax error after '%s'\n",
+ t == tLOG_EQ ? "==" : t == tLOG_NOT_EQ ? "!=" :
+ t == tGREATER ? ">" : t == tGREATER_EQ ? ">=" :
+ t == tLESS ? "<" : "<=");
db_error(NULL);
/*NOTREACHED*/
}
diff --git a/sys/ddb/db_main.c b/sys/ddb/db_main.c
index 3345bb6..da6a513 100644
--- a/sys/ddb/db_main.c
+++ b/sys/ddb/db_main.c
@@ -226,10 +226,7 @@ db_trap(int type, int code)
if (cnunavailable())
return (0);
- bkpt = IS_BREAKPOINT_TRAP(type, code);
- watchpt = IS_WATCHPOINT_TRAP(type, code);
-
- if (db_stop_at_pc(&bkpt)) {
+ if (db_stop_at_pc(type, code, &bkpt, &watchpt)) {
if (db_inst_count) {
db_printf("After %d instructions (%d loads, %d stores),\n",
db_inst_count, db_load_count, db_store_count);
diff --git a/sys/ddb/db_run.c b/sys/ddb/db_run.c
index 5250651..4d8d3c7 100644
--- a/sys/ddb/db_run.c
+++ b/sys/ddb/db_run.c
@@ -48,15 +48,15 @@ __FBSDID("$FreeBSD$");
#include <ddb/db_break.h>
#include <ddb/db_access.h>
-static int db_run_mode;
-#define STEP_NONE 0
#define STEP_ONCE 1
#define STEP_RETURN 2
#define STEP_CALLT 3
#define STEP_CONTINUE 4
#define STEP_INVISIBLE 5
#define STEP_COUNT 6
+static int db_run_mode = STEP_CONTINUE;
+static bool db_sstep_multiple;
static bool db_sstep_print;
static int db_loop_count;
static int db_call_depth;
@@ -90,13 +90,14 @@ db_pc_is_singlestep(db_addr_t pc)
#endif
bool
-db_stop_at_pc(bool *is_breakpoint)
+db_stop_at_pc(int type, int code, bool *is_breakpoint, bool *is_watchpoint)
{
db_addr_t pc;
db_breakpoint_t bkpt;
+ *is_breakpoint = IS_BREAKPOINT_TRAP(type, code);
+ *is_watchpoint = IS_WATCHPOINT_TRAP(type, code);
pc = PC_REGS();
-
if (db_pc_is_singlestep(pc))
*is_breakpoint = false;
@@ -125,13 +126,39 @@ db_stop_at_pc(bool *is_breakpoint)
*is_breakpoint = true;
return (true); /* stop here */
}
+ return (false); /* continue the countdown */
} else if (*is_breakpoint) {
#ifdef BKPT_SKIP
BKPT_SKIP;
#endif
}
- *is_breakpoint = false;
+ *is_breakpoint = false; /* might be a breakpoint, but not ours */
+
+ /*
+ * If not stepping, then silently ignore single-step traps
+ * (except for clearing the single-step-flag above).
+ *
+ * If stepping, then abort if the trap type is unexpected.
+ * Breakpoints owned by us are expected and were handled above.
+ * Single-steps are expected and are handled below. All others
+ * are unexpected.
+ *
+ * Only do either of these if the MD layer claims to classify
+ * single-step traps unambiguously (by defining IS_SSTEP_TRAP).
+ * Otherwise, fall through to the bad historical behaviour
+ * given by turning unexpected traps into expected traps: if not
+ * stepping, then expect only breakpoints and stop, and if
+ * stepping, then expect only single-steps and step.
+ */
+#ifdef IS_SSTEP_TRAP
+ if (db_run_mode == STEP_CONTINUE && IS_SSTEP_TRAP(type, code))
+ return (false);
+ if (db_run_mode != STEP_CONTINUE && !IS_SSTEP_TRAP(type, code)) {
+ printf("Stepping aborted\n");
+ return (true);
+ }
+#endif
if (db_run_mode == STEP_INVISIBLE) {
db_run_mode = STEP_CONTINUE;
@@ -184,7 +211,6 @@ db_stop_at_pc(bool *is_breakpoint)
return (false); /* continue */
}
}
- db_run_mode = STEP_NONE;
return (true);
}
@@ -194,6 +220,7 @@ db_restart_at_pc(bool watchpt)
db_addr_t pc = PC_REGS();
if ((db_run_mode == STEP_COUNT) ||
+ ((db_run_mode == STEP_ONCE) && db_sstep_multiple) ||
(db_run_mode == STEP_RETURN) ||
(db_run_mode == STEP_CALLT)) {
/*
@@ -321,6 +348,7 @@ db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
db_run_mode = STEP_ONCE;
db_loop_count = count;
+ db_sstep_multiple = (count != 1);
db_sstep_print = print;
db_inst_count = 0;
db_load_count = 0;
diff --git a/sys/ddb/ddb.h b/sys/ddb/ddb.h
index a2adcdf..fcf772b 100644
--- a/sys/ddb/ddb.h
+++ b/sys/ddb/ddb.h
@@ -215,7 +215,8 @@ void db_restart_at_pc(bool watchpt);
int db_set_variable(db_expr_t value);
void db_set_watchpoints(void);
void db_skip_to_eol(void);
-bool db_stop_at_pc(bool *is_breakpoint);
+bool db_stop_at_pc(int type, int code, bool *is_breakpoint,
+ bool *is_watchpoint);
#define db_strcpy strcpy
void db_trace_self(void);
int db_trace_thread(struct thread *, int);
diff --git a/sys/i386/i386/db_disasm.c b/sys/i386/i386/db_disasm.c
index 2b398da..5728fe5 100644
--- a/sys/i386/i386/db_disasm.c
+++ b/sys/i386/i386/db_disasm.c
@@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
* Instruction disassembler.
*/
#include <sys/param.h>
+#include <sys/kdb.h>
#include <ddb/ddb.h>
#include <ddb/db_access.h>
@@ -1168,9 +1169,17 @@ db_disasm(db_addr_t loc, bool altfmt)
int len;
struct i_addr address;
+ if (db_segsize(kdb_frame) == 16)
+ altfmt = !altfmt;
get_value_inc(inst, loc, 1, FALSE);
- short_addr = FALSE;
- size = LONG;
+ if (altfmt) {
+ short_addr = TRUE;
+ size = WORD;
+ }
+ else {
+ short_addr = FALSE;
+ size = LONG;
+ }
seg = NULL;
/*
diff --git a/sys/i386/i386/db_interface.c b/sys/i386/i386/db_interface.c
index 7079e56..3c0ac81 100644
--- a/sys/i386/i386/db_interface.c
+++ b/sys/i386/i386/db_interface.c
@@ -135,6 +135,30 @@ db_write_bytes(vm_offset_t addr, size_t size, char *data)
return (ret);
}
+int
+db_segsize(struct trapframe *tfp)
+{
+ struct proc_ldt *plp;
+ struct segment_descriptor *sdp;
+ int sel;
+
+ if (tfp == NULL)
+ return (32);
+ if (tfp->tf_eflags & PSL_VM)
+ return (16);
+ sel = tfp->tf_cs & 0xffff;
+ if (sel == GSEL(GCODE_SEL, SEL_KPL))
+ return (32);
+ /* Rare cases follow. User mode cases are currently unreachable. */
+ if (ISLDT(sel)) {
+ plp = curthread->td_proc->p_md.md_ldt;
+ sdp = (plp != NULL) ? &plp->ldt_sd : &ldt[0].sd;
+ } else {
+ sdp = &gdt[PCPU_GET(cpuid) * NGDT].sd;
+ }
+ return (sdp[IDXSEL(sel)].sd_def32 == 0 ? 16 : 32);
+}
+
void
db_show_mdpcpu(struct pcpu *pc)
{
diff --git a/sys/i386/i386/db_trace.c b/sys/i386/i386/db_trace.c
index 3563579..4f5f413 100644
--- a/sys/i386/i386/db_trace.c
+++ b/sys/i386/i386/db_trace.c
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
#include <sys/sysent.h>
#include <machine/cpu.h>
+#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/reg.h>
@@ -81,8 +82,7 @@ struct db_variable *db_eregs = db_regs + nitems(db_regs);
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));
+ return (TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp);
}
static int
@@ -104,12 +104,32 @@ db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
static int
db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
{
+ struct trapframe_vm86 *tfp;
+ int off;
uint16_t *reg;
if (kdb_frame == NULL)
return (0);
- reg = (uint16_t *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
+ off = (intptr_t)vp->valuep;
+ if (kdb_frame->tf_eflags & PSL_VM) {
+ tfp = (void *)kdb_frame;
+ switch ((intptr_t)vp->valuep) {
+ case (intptr_t)DB_OFFSET(tf_cs):
+ reg = (uint16_t *)&tfp->tf_cs;
+ break;
+ case (intptr_t)DB_OFFSET(tf_ds):
+ reg = (uint16_t *)&tfp->tf_vm86_ds;
+ break;
+ case (intptr_t)DB_OFFSET(tf_es):
+ reg = (uint16_t *)&tfp->tf_vm86_es;
+ break;
+ case (intptr_t)DB_OFFSET(tf_fs):
+ reg = (uint16_t *)&tfp->tf_vm86_fs;
+ break;
+ }
+ } else
+ reg = (uint16_t *)((uintptr_t)kdb_frame + off);
if (op == DB_VAR_GET)
*valuep = *reg;
else
@@ -126,7 +146,7 @@ db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
if (op == DB_VAR_GET)
*valuep = get_esp(kdb_frame);
- else if (ISPL(kdb_frame->tf_cs))
+ else if (TF_HAS_STACKREGS(kdb_frame))
kdb_frame->tf_esp = *valuep;
return (1);
}
@@ -134,7 +154,16 @@ db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
static int
db_gs(struct db_variable *vp, db_expr_t *valuep, int op)
{
+ struct trapframe_vm86 *tfp;
+ if (kdb_frame != NULL && kdb_frame->tf_eflags & PSL_VM) {
+ tfp = (void *)kdb_frame;
+ if (op == DB_VAR_GET)
+ *valuep = tfp->tf_vm86_gs;
+ else
+ tfp->tf_vm86_gs = *valuep;
+ return (1);
+ }
if (op == DB_VAR_GET)
*valuep = rgs();
else
@@ -150,8 +179,9 @@ db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
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))
+ *valuep = TF_HAS_STACKREGS(kdb_frame) ? kdb_frame->tf_ss :
+ rss();
+ else if (TF_HAS_STACKREGS(kdb_frame))
kdb_frame->tf_ss = *valuep;
return (1);
}
@@ -391,6 +421,17 @@ db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
int instr, narg;
boolean_t first;
+ if (db_segsize(tf) == 16) {
+ db_printf(
+"--- 16-bit%s, cs:eip = %#x:%#x, ss:esp = %#x:%#x, ebp = %#x, tf = %p ---\n",
+ (tf->tf_eflags & PSL_VM) ? " (vm86)" : "",
+ tf->tf_cs, tf->tf_eip,
+ TF_HAS_STACKREGS(tf) ? tf->tf_ss : rss(),
+ TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp,
+ tf->tf_ebp, tf);
+ return (0);
+ }
+
/*
* If an indirect call via an invalid pointer caused a trap,
* %pc contains the invalid address while the return address
@@ -408,7 +449,7 @@ db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
* 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))
+ if (TF_HAS_STACKREGS(kdb_frame))
instr = (int)(kdb_frame + 1);
else
instr = (int)&kdb_frame->tf_esp;
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index c540a49..3decfd43 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -189,7 +189,10 @@ trap(struct trapframe *frame)
#endif
struct thread *td = curthread;
struct proc *p = td->td_proc;
- int i = 0, ucode = 0, code;
+#ifdef KDB
+ register_t dr6;
+#endif
+ int i = 0, ucode = 0;
u_int type;
register_t addr = 0;
vm_offset_t eva;
@@ -267,7 +270,8 @@ trap(struct trapframe *frame)
* interrupts disabled until they are accidentally
* enabled later.
*/
- if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM))
+ if (TRAPF_USERMODE(frame) &&
+ (curpcb->pcb_flags & PCB_VM86CALL) == 0)
uprintf(
"pid %ld (%s): trap %d with interrupts disabled\n",
(long)curproc->p_pid, curthread->td_name, type);
@@ -291,7 +295,6 @@ trap(struct trapframe *frame)
}
}
eva = 0;
- code = frame->tf_err;
if (type == T_PAGEFLT) {
/*
* For some Cyrix CPUs, %cr2 is clobbered by
@@ -307,9 +310,7 @@ trap(struct trapframe *frame)
enable_intr();
}
- if ((ISPL(frame->tf_cs) == SEL_UPL) ||
- ((frame->tf_eflags & PSL_VM) &&
- !(curpcb->pcb_flags & PCB_VM86CALL))) {
+ if (TRAPF_USERMODE(frame) && (curpcb->pcb_flags & PCB_VM86CALL) == 0) {
/* user trap */
td->td_pticks = 0;
@@ -335,6 +336,7 @@ trap(struct trapframe *frame)
goto out;
}
#endif
+user_trctrap_out:
frame->tf_eflags &= ~PSL_T;
i = SIGTRAP;
ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
@@ -360,6 +362,11 @@ trap(struct trapframe *frame)
case T_STKFLT: /* stack fault */
if (frame->tf_eflags & PSL_VM) {
i = vm86_emulate((struct vm86frame *)frame);
+ if (i == SIGTRAP) {
+ type = T_TRCTRAP;
+ load_dr6(rdr6() | 0x4000);
+ goto user_trctrap_out;
+ }
if (i == 0)
goto user;
break;
@@ -461,7 +468,7 @@ trap(struct trapframe *frame)
goto userout;
#else /* !POWERFAIL_NMI */
/* machine/parity/power fail/"kitchen sink" faults */
- if (isa_nmi(code) == 0) {
+ if (isa_nmi(frame->tf_err) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
@@ -566,6 +573,11 @@ trap(struct trapframe *frame)
case T_STKFLT: /* stack fault */
if (frame->tf_eflags & PSL_VM) {
i = vm86_emulate((struct vm86frame *)frame);
+ if (i == SIGTRAP) {
+ type = T_TRCTRAP;
+ load_dr6(rdr6() | 0x4000);
+ goto kernel_trctrap;
+ }
if (i != 0)
/*
* returns to original process
@@ -654,6 +666,7 @@ trap(struct trapframe *frame)
break;
case T_TRCTRAP: /* trace trap */
+kernel_trctrap:
if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) {
/*
* We've just entered system mode via the
@@ -687,7 +700,7 @@ trap(struct trapframe *frame)
* Reset breakpoint bits because the
* processor doesn't
*/
- load_dr6(rdr6() & 0xfffffff0);
+ load_dr6(rdr6() & ~0xf);
goto out;
}
/*
@@ -699,7 +712,10 @@ trap(struct trapframe *frame)
* Otherwise, debugger traps "can't happen".
*/
#ifdef KDB
- if (kdb_trap(type, 0, frame))
+ /* XXX %dr6 is not quite reentrant. */
+ dr6 = rdr6();
+ load_dr6(dr6 & ~0x4000);
+ if (kdb_trap(type, dr6, frame))
goto out;
#endif
break;
@@ -715,7 +731,7 @@ trap(struct trapframe *frame)
goto out;
#else /* !POWERFAIL_NMI */
/* machine/parity/power fail/"kitchen sink" faults */
- if (isa_nmi(code) == 0) {
+ if (isa_nmi(frame->tf_err) == 0) {
#ifdef KDB
/*
* NMI can be hooked up to a pushbutton
@@ -953,7 +969,7 @@ trap_fatal(frame, eva)
}
printf("instruction pointer = 0x%x:0x%x\n",
frame->tf_cs & 0xffff, frame->tf_eip);
- if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
+ if (TF_HAS_STACKREGS(frame)) {
ss = frame->tf_ss & 0xffff;
esp = frame->tf_esp;
} else {
@@ -1107,7 +1123,8 @@ syscall(struct trapframe *frame)
ksiginfo_t ksi;
#ifdef DIAGNOSTIC
- if (ISPL(frame->tf_cs) != SEL_UPL) {
+ if (!(TRAPF_USERMODE(frame) &&
+ (curpcb->pcb_flags & PCB_VM86CALL) == 0)) {
panic("syscall");
/* NOT REACHED */
}
diff --git a/sys/i386/i386/vm86.c b/sys/i386/i386/vm86.c
index 93ff855..baa1912 100644
--- a/sys/i386/i386/vm86.c
+++ b/sys/i386/i386/vm86.c
@@ -171,7 +171,7 @@ vm86_emulate(vmf)
PUSHL((vmf->vmf_eflags & PUSH_MASK)
| PSL_IOPL, vmf);
vmf->vmf_ip += inc_ip;
- return (0);
+ return (retcode);
case POPF:
temp_flags = POPL(vmf) & POP_MASK;
@@ -185,7 +185,7 @@ vm86_emulate(vmf)
} else {
vmf->vmf_eflags &= ~PSL_VIF;
}
- return (0);
+ return (retcode);
}
break;
@@ -203,7 +203,7 @@ vm86_emulate(vmf)
case INTn:
break;
- /* VME if trying to set PSL_TF, or PSL_I when VIP is set */
+ /* VME if trying to set PSL_T, or PSL_I when VIP is set */
case POPF:
temp_flags = POP(vmf) & POP_MASK;
vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
@@ -218,7 +218,7 @@ vm86_emulate(vmf)
}
return (retcode);
- /* VME if trying to set PSL_TF, or PSL_I when VIP is set */
+ /* VME if trying to set PSL_T, or PSL_I when VIP is set */
case IRET:
vmf->vmf_ip = POP(vmf);
vmf->vmf_cs = POP(vmf);
diff --git a/sys/i386/include/db_machdep.h b/sys/i386/include/db_machdep.h
index 27207a8..e8d1d8e 100644
--- a/sys/i386/include/db_machdep.h
+++ b/sys/i386/include/db_machdep.h
@@ -35,7 +35,10 @@
typedef vm_offset_t db_addr_t; /* address - unsigned */
typedef int db_expr_t; /* expression - signed */
-#define PC_REGS() ((db_addr_t)kdb_thrctx->pcb_eip)
+#define PC_REGS() ((db_addr_t)(kdb_frame->tf_eflags & PSL_VM ? \
+ (kdb_frame->tf_eip & 0xffff) + \
+ ((kdb_frame->tf_cs & 0xffff) << 4) : \
+ kdb_frame->tf_eip))
#define BKPT_INST 0xcc /* breakpoint instruction */
#define BKPT_SIZE (1) /* size of breakpoint inst */
@@ -56,12 +59,16 @@ do { \
#define db_clear_single_step kdb_cpu_clear_singlestep
#define db_set_single_step kdb_cpu_set_singlestep
-#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
/*
- * Watchpoints are not supported. The debug exception type is in %dr6
- * and not yet in the args to this macro.
+ * The debug exception type is copied from %dr6 to 'code' and used to
+ * disambiguate single step traps. Watchpoints have no special support.
+ * Our hardware breakpoints are not well integrated with ddb and are too
+ * different from watchpoints. ddb treats them as unknown traps with
+ * unknown addresses and doesn't turn them off while it is running.
*/
-#define IS_WATCHPOINT_TRAP(type, code) 0
+#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
+#define IS_SSTEP_TRAP(type, code) ((type) == T_TRCTRAP && (code) & 0x4000)
+#define IS_WATCHPOINT_TRAP(type, code) 0
#define I_CALL 0xe8
#define I_CALLI 0xff
@@ -91,4 +98,6 @@ do { \
#define DB_SMALL_VALUE_MAX 0x7fffffff
#define DB_SMALL_VALUE_MIN (-0x400001)
+int db_segsize(struct trapframe *tfp);
+
#endif /* !_MACHINE_DB_MACHDEP_H_ */
diff --git a/sys/x86/include/frame.h b/sys/x86/include/frame.h
index a32ef7c..7418736 100644
--- a/sys/x86/include/frame.h
+++ b/sys/x86/include/frame.h
@@ -64,7 +64,7 @@ struct trapframe {
int tf_eip;
int tf_cs;
int tf_eflags;
- /* below only when crossing rings (e.g. user to kernel) */
+ /* below only when crossing rings (user to kernel) */
int tf_esp;
int tf_ss;
};
@@ -89,15 +89,24 @@ struct trapframe_vm86 {
int tf_eip;
int tf_cs;
int tf_eflags;
- /* below only when crossing rings (e.g. user to kernel) */
+ /* below only when crossing rings (user (including vm86) to kernel) */
int tf_esp;
int tf_ss;
- /* below only when switching out of VM86 mode */
+ /* below only when crossing from vm86 mode to kernel */
int tf_vm86_es;
int tf_vm86_ds;
int tf_vm86_fs;
int tf_vm86_gs;
};
+
+/*
+ * This alias for the MI TRAPF_USERMODE() should be used when we don't
+ * care about user mode itself, but need to know if a frame has stack
+ * registers. The difference is only logical, but on i386 the logic
+ * for using TRAPF_USERMODE() is complicated by sometimes treating vm86
+ * bioscall mode (which is a special ring 3 user mode) as kernel mode.
+ */
+#define TF_HAS_STACKREGS(tf) TRAPF_USERMODE(tf)
#endif /* __i386__ */
#ifdef __amd64__
@@ -136,6 +145,7 @@ struct trapframe {
register_t tf_rip;
register_t tf_cs;
register_t tf_rflags;
+ /* the amd64 frame always has the stack registers */
register_t tf_rsp;
register_t tf_ss;
};
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