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-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
6 files changed, 130 insertions, 30 deletions
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_ */
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