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Bochs/bochs/patches/patch.consistent2b
Bryce Denney bf983610b9 - commit patch which fixes all known trace-on problems. This patch is 
for Bochs 1.2.
2001-09-27 14:08:04 +00:00

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----------------------------------------------------------------------
Patch name: patch.consistent2b
Author: Bryce Denney
Date: Thu Sep 27 10:14:30 EDT 2001
Detailed description:
This patch fixes a number of debugger problems.
- with trace-on, simulation time would pass 5x faster than usual, so
interrupts and other timed events would happen at different times
- with trace-on, breakpoints were ignored
- with trace-on, control-C would not stop the processor and return to the
debugger.
This patch changes the execution quantum for the debugger to 1, which means
that cpu_loop is asked to do one instruction at a time. This may cause
bochs with the debugger to be slower than before.
I haven't tested without the debugger yet, so I don't know if the timing
of events matches or not.
Apply patch to:
Bochs 1.2
Instructions:
To patch, go to main bochs directory.
Type "patch -p0 < THIS_PATCH_FILE".
----------------------------------------------------------------------
? cpu/Makefile
? cpu/both.cc
? debug/Makefile
Index: cpu/cpu.cc
===================================================================
RCS file: /cvsroot/bochs/bochs/cpu/cpu.cc,v
retrieving revision 1.6
diff -u -r1.6 cpu.cc
--- cpu/cpu.cc 2001/05/24 18:46:34 1.6
+++ cpu/cpu.cc 2001/09/27 14:01:23
@@ -281,6 +281,14 @@
CHECK_MAX_INSTRUCTIONS(max_instr_count);
#if BX_DEBUGGER
+ if (BX_CPU_THIS_PTR trace) {
+ // print the instruction that was just executed. This used to
+ // return with a certain stop reason, but as a result the tracing
+ // affected simulation, which is obviously bad when you're trying
+ // to debug a problem.
+ bx_dbg_disassemble_current (-1);
+ }
+
// BW vm mode switch support is in dbg_is_begin_instr_bpoint
// note instr generating exceptions never reach this point.
@@ -317,14 +325,9 @@
}
}
#endif
- if (BX_CPU_THIS_PTR trace) {
- BX_CPU_THIS_PTR stop_reason = STOP_TRACE;
- return;
- }
-#endif
-#if BX_DEBUGGER
{
+ // check for icount or control-C. If found, set guard reg and return.
Bit32u debug_eip = BX_CPU_THIS_PTR prev_eip;
if ( dbg_is_end_instr_bpoint(
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value,
@@ -334,6 +337,7 @@
return;
}
}
+
#endif // #if BX_DEBUGGER
goto main_cpu_loop;
}
@@ -613,6 +617,7 @@
BX_CPU_C::dbg_is_begin_instr_bpoint(Bit32u cs, Bit32u eip, Bit32u laddr,
Bit32u is_32)
{
+ //fprintf (stderr, "begin_instr_bp: checking cs:eip %04x:%08x\n", cs, eip);
BX_CPU_THIS_PTR guard_found.cs = cs;
BX_CPU_THIS_PTR guard_found.eip = eip;
BX_CPU_THIS_PTR guard_found.laddr = laddr;
@@ -672,7 +677,14 @@
Boolean valid;
dbg_xlate_linear2phy(BX_CPU_THIS_PTR guard_found.laddr,
&phy, &valid);
- if ( (BX_CPU_THIS_PTR guard_found.icount!=0) && valid ) {
+ // why the condition "guard_found.icount!=0"? That means that
+ // breakpoints only occur when you're using "continue" but never
+ // when you're using "step". I'm going to try disabling taht
+ // condition and see what happens. This caused it to stop at
+ // a breakpoint even while trace-on is on.
+ if ( valid
+ //&& (BX_CPU_THIS_PTR guard_found.icount!=0)
+ ) {
for (unsigned i=0; i<bx_guard.iaddr.num_physical; i++) {
if ( bx_guard.iaddr.phy[i].addr == phy ) {
BX_CPU_THIS_PTR guard_found.guard_found = BX_DBG_GUARD_IADDR_PHY;
@@ -692,8 +704,16 @@
BX_CPU_C::dbg_is_end_instr_bpoint(Bit32u cs, Bit32u eip, Bit32u laddr,
Bit32u is_32)
{
+ //fprintf (stderr, "end_instr_bp: checking for icount or ^C\n");
BX_CPU_THIS_PTR guard_found.icount++;
+ // convenient point to see if user typed Ctrl-C
+ if (bx_guard.interrupt_requested &&
+ (bx_guard.guard_for & BX_DBG_GUARD_CTRL_C)) {
+ BX_CPU_THIS_PTR guard_found.guard_found = BX_DBG_GUARD_CTRL_C;
+ return(1);
+ }
+
// see if debugger requesting icount guard
if (bx_guard.guard_for & BX_DBG_GUARD_ICOUNT) {
if (BX_CPU_THIS_PTR guard_found.icount >= bx_guard.icount) {
@@ -704,13 +724,6 @@
BX_CPU_THIS_PTR guard_found.guard_found = BX_DBG_GUARD_ICOUNT;
return(1);
}
- }
-
- // convenient point to see if user typed Ctrl-C
- if (bx_guard.interrupt_requested &&
- (bx_guard.guard_for & BX_DBG_GUARD_CTRL_C)) {
- BX_CPU_THIS_PTR guard_found.guard_found = BX_DBG_GUARD_CTRL_C;
- return(1);
}
#if (BX_NUM_SIMULATORS >= 2)
Index: debug/dbg_main.cc
===================================================================
RCS file: /cvsroot/bochs/bochs/debug/dbg_main.cc,v
retrieving revision 1.9.2.1
diff -u -r1.9.2.1 dbg_main.cc
--- debug/dbg_main.cc 2001/05/29 14:28:38 1.9.2.1
+++ debug/dbg_main.cc 2001/09/27 14:01:29
@@ -1482,13 +1482,18 @@
bx_guard.interrupt_requested = 0;
int stop = 0;
int which = -1;
+ int max_instr_executed = 0;
while (!stop) {
- int quantum = 5; // arbitrary number of cycles to run in each
+ int quantum = 1; // arbitrary number of cycles to run in each
for (int cpu=0; cpu < BX_SMP_PROCESSORS; cpu++) {
BX_CPU(cpu)->guard_found.guard_found = 0;
BX_CPU(cpu)->guard_found.icount = 0;
bx_guard.icount = quantum;
BX_CPU(cpu)->cpu_loop (-1);
+ /// check out BX_CPU(cpu)->guard_found.icount
+ //fprintf (stderr, "dbg_cont: after cpu_loop guard_found.icount=%d\n", BX_CPU(cpu)->guard_found.icount);
+ if (BX_CPU(cpu)->guard_found.icount > max_instr_executed)
+ max_instr_executed = BX_CPU(cpu)->guard_found.icount;
// set stop flag if a guard found other than icount or halted
unsigned long found = BX_CPU(cpu)->guard_found.guard_found;
stop_reason_t reason = (stop_reason_t) BX_CPU(cpu)->stop_reason;
@@ -1507,7 +1512,13 @@
// cpus set stop, too bad.
}
// increment time tick only after all processors have had their chance.
- BX_TICKN(quantum);
+ // MAJOR PROBLEM: we should tick by the number of instructions
+ // that were ACTUALLY executed, not the number that we asked it
+ // to execute. When tracing is on, only one instruction is
+ // executed, not quantum. As a result, when you trace you get
+ // ticks speeding ahead at 5x normal speed.
+ BX_TICKN(max_instr_executed);
+ //BX_TICKN(quantum);
}
#endif
@@ -1517,10 +1528,6 @@
BX_INSTR_DEBUG_PROMPT();
bx_dbg_print_guard_results();
- if (BX_CPU(which)->stop_reason == STOP_TRACE
- || BX_CPU(which)->stop_reason == STOP_CPU_HALTED)
- goto one_more;
-
if (watchpoint_continue && (BX_CPU(which)->stop_reason == STOP_READ_WATCH_POINT ||
BX_CPU(which)->stop_reason == STOP_WRITE_WATCH_POINT))
goto one_more;
@@ -1972,7 +1979,47 @@
#endif
+void bx_dbg_disassemble_current (int which_cpu)
+{
+ Bit32u phy;
+ Boolean valid;
+
+ if (which_cpu < 0) {
+ // iterate over all of them.
+ for (int i=0; i<BX_NUM_SIMULATORS; i++)
+ bx_dbg_disassemble_current (i);
+ return;
+ }
+
+ BX_CPU(which_cpu)->dbg_xlate_linear2phy(BX_CPU(which_cpu)->guard_found.laddr, &phy, &valid);
+
+ if (valid) {
+ unsigned ilen;
+ BX_CPU(which_cpu)->mem->dbg_fetch_mem(phy, 16, bx_disasm_ibuf);
+ ilen = bx_disassemble.disasm(BX_CPU(which_cpu)->guard_found.is_32bit_code,
+ bx_disasm_ibuf, bx_disasm_tbuf);
+
+ if (BX_CPU(which_cpu)->guard_found.is_32bit_code) {
+ fprintf(stderr, "(%u) %04x:%08x (%s): ", which_cpu,
+ (unsigned) BX_CPU(which_cpu)->guard_found.cs,
+ (unsigned) BX_CPU(which_cpu)->guard_found.eip,
+ bx_dbg_symbolic_address((BX_CPU(which_cpu)->cr3) >> 12, BX_CPU(which_cpu)->guard_found.eip, BX_CPU(which_cpu)->sregs[BX_SREG_CS].cache.u.segment.base));
+ }
+ else {
+ fprintf(stderr, "(%u) %04x:%04x: ", which_cpu,
+ (unsigned) BX_CPU(which_cpu)->guard_found.cs,
+ (unsigned) BX_CPU(which_cpu)->guard_found.eip);
+ }
+ for (unsigned j=0; j<ilen; j++)
+ fprintf(stderr, "%02x", (unsigned) bx_disasm_ibuf[j]);
+ fprintf(stderr, ": %s\n", bx_disasm_tbuf);
+ }
+ else {
+ fprintf(stderr, "(%u) ??? (physical address not available)\n", which_cpu);
+ }
+}
+
void
bx_dbg_print_guard_results(void)
{
@@ -2019,8 +2066,6 @@
}
else if (BX_CPU(sim)->stop_reason == STOP_MAGIC_BREAK_POINT) {
fprintf(stderr, "(%u) Magic breakpoint\n", sim);
- } else if (BX_CPU(sim)->stop_reason == STOP_TRACE) {
- /* Nothing */
} else if (BX_CPU(sim)->stop_reason == STOP_TIME_BREAK_POINT) {
fprintf(stderr, "(%u) Caught time breakpoint\n", sim);
} else if (BX_CPU(sim)->stop_reason == STOP_MODE_BREAK_POINT) {
@@ -2036,40 +2081,14 @@
sim, BX_CPU(sim)->stop_reason);
}
-
#if BX_DISASM
if (bx_debugger.auto_disassemble) {
- Bit32u phy;
- Boolean valid;
-
- BX_CPU(sim)->dbg_xlate_linear2phy(BX_CPU(sim)->guard_found.laddr, &phy, &valid);
-
- if (valid) {
- unsigned ilen;
-
- BX_CPU(sim)->mem->dbg_fetch_mem(phy, 16, bx_disasm_ibuf);
- ilen = bx_disassemble.disasm(BX_CPU(sim)->guard_found.is_32bit_code,
- bx_disasm_ibuf, bx_disasm_tbuf);
-
- if (BX_CPU(sim)->guard_found.is_32bit_code) {
- fprintf(stderr, "(%u) %04x:%08x (%s): ", sim,
- (unsigned) BX_CPU(sim)->guard_found.cs,
- (unsigned) BX_CPU(sim)->guard_found.eip,
- bx_dbg_symbolic_address((BX_CPU(sim)->cr3) >> 12, BX_CPU(sim)->guard_found.eip, BX_CPU(sim)->sregs[BX_SREG_CS].cache.u.segment.base));
- }
- else {
- fprintf(stderr, "(%u) %04x:%04x: ", sim,
- (unsigned) BX_CPU(sim)->guard_found.cs,
- (unsigned) BX_CPU(sim)->guard_found.eip);
- }
- for (unsigned j=0; j<ilen; j++)
- fprintf(stderr, "%02x", (unsigned) bx_disasm_ibuf[j]);
- fprintf(stderr, ": %s\n", bx_disasm_tbuf);
- }
- else {
- fprintf(stderr, "(%u) ??? (physical address not available)\n", sim);
- }
- }
+ // if tracing is on for this cpu, we've already printed the disassembly
+ // for the instruction that's about to be executed. So omit the
+ // disassembly here. (experiment)
+ if (! BX_CPU(sim)->trace)
+ bx_dbg_disassemble_current (sim);
+ }
#endif // #if BX_DISASM
}
}
Index: debug/debug.h
===================================================================
RCS file: /cvsroot/bochs/bochs/debug/debug.h,v
retrieving revision 1.4
diff -u -r1.4 debug.h
--- debug/debug.h 2001/05/23 08:16:07 1.4
+++ debug/debug.h 2001/09/27 14:01:29
@@ -148,7 +148,7 @@
extern Bit32u read_watchpoint[MAX_READ_WATCHPOINTS];
typedef enum {
- STOP_NO_REASON = 0, STOP_TIME_BREAK_POINT, STOP_READ_WATCH_POINT, STOP_WRITE_WATCH_POINT, STOP_MAGIC_BREAK_POINT, STOP_TRACE, STOP_MODE_BREAK_POINT, STOP_CPU_HALTED
+ STOP_NO_REASON = 0, STOP_TIME_BREAK_POINT, STOP_READ_WATCH_POINT, STOP_WRITE_WATCH_POINT, STOP_MAGIC_BREAK_POINT, UNUSED_STOP_TRACE, STOP_MODE_BREAK_POINT, STOP_CPU_HALTED
} stop_reason_t;
typedef enum {
@@ -403,6 +403,7 @@
void bx_dbg_raise_HLDA(void);
Bit8u bx_dbg_IAC(void);
void bx_dbg_set_INTR(Boolean b);
+void bx_dbg_disassemble_current (int which_cpu);
int bx_dbg_symbolic_output(void); /* BW */
#endif // #ifdef __cplusplus
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