kdb_dbtrap_t
kdba_db_trap(struct pt_regs *regs, int error_unused)
{
kdb_machreg_t dr6;
kdb_machreg_t dr7;
int rw, reg;
int i;
kdb_dbtrap_t rv = KDB_DB_BPT;
kdb_bp_t *bp;
if (KDB_NULL_REGS(regs))
return KDB_DB_NOBPT;
dr6 = kdba_getdr6();
dr7 = kdba_getdr7();
if (KDB_DEBUG(BP))
kdb_printf("kdb: dr6 0x%lx dr7 0x%lx\n", dr6, dr7);
if (dr6 & DR6_BS) {
if (KDB_STATE(SSBPT)) {
if (KDB_DEBUG(BP))
kdb_printf("ssbpt\n");
KDB_STATE_CLEAR(SSBPT);
for(i=0,bp=kdb_breakpoints;
i < KDB_MAXBPT;
i++, bp++) {
if (KDB_DEBUG(BP))
kdb_printf("bp 0x%p enabled %d delayed %d global %d cpu %d\n",
bp, bp->bp_enabled, bp->bp_delayed, bp->bp_global, bp->bp_cpu);
if (!bp->bp_enabled)
continue;
if (!bp->bp_global && bp->bp_cpu != smp_processor_id())
continue;
if (KDB_DEBUG(BP))
kdb_printf("bp for this cpu\n");
if (bp->bp_delayed) {
bp->bp_delayed = 0;
if (KDB_DEBUG(BP))
kdb_printf("kdba_installbp\n");
kdba_installbp(regs, bp);
if (!KDB_STATE(DOING_SS)) {
regs->eflags &= ~EF_TF;
return(KDB_DB_SSBPT);
}
break;
}
}
if (i == KDB_MAXBPT) {
kdb_printf("kdb: Unable to find delayed breakpoint\n");
}
if (!KDB_STATE(DOING_SS)) {
regs->eflags &= ~EF_TF;
return(KDB_DB_NOBPT);
}
/* FALLTHROUGH */
}
/*
* KDB_STATE_DOING_SS is set when the kernel debugger is using
* the processor trap flag to single-step a processor. If a
* single step trap occurs and this flag is clear, the SS trap
* will be ignored by KDB and the kernel will be allowed to deal
* with it as necessary (e.g. for ptrace).
*/
if (!KDB_STATE(DOING_SS))
goto unknown;
/* single step */
rv = KDB_DB_SS; /* Indicate single step */
if (KDB_STATE(DOING_SSB)) {
unsigned char instruction[2];
kdb_id1(regs->rip);
if (kdb_getarea(instruction, regs->rip) ||
(instruction[0]&0xf0) == 0xe0 || /* short disp jumps */
(instruction[0]&0xf0) == 0x70 || /* Misc. jumps */
instruction[0] == 0xc2 || /* ret */
instruction[0] == 0x9a || /* call */
(instruction[0]&0xf8) == 0xc8 || /* enter, leave, iret, int, */
((instruction[0] == 0x0f) &&
((instruction[1]&0xf0)== 0x80))
) {
/*
* End the ssb command here.
*/
KDB_STATE_CLEAR(DOING_SSB);
KDB_STATE_CLEAR(DOING_SS);
} else {
rv = KDB_DB_SSB; /* Indicate ssb - dismiss immediately */
}
} else {
/*
* Print current insn
*/
kdb_printf("SS trap at ");
kdb_symbol_print(regs->rip, NULL, KDB_SP_DEFAULT|KDB_SP_NEWLINE);
kdb_id1(regs->rip);
KDB_STATE_CLEAR(DOING_SS);
}
if (rv != KDB_DB_SSB)
regs->eflags &= ~EF_TF;
}
if (dr6 & DR6_B0) {
rw = DR7_RW0(dr7);
reg = 0;
goto handle;
}
if (dr6 & DR6_B1) {
rw = DR7_RW1(dr7);
reg = 1;
goto handle;
}
if (dr6 & DR6_B2) {
rw = DR7_RW2(dr7);
reg = 2;
goto handle;
}
if (dr6 & DR6_B3) {
rw = DR7_RW3(dr7);
reg = 3;
goto handle;
}
if (rv > 0)
goto handled;
goto unknown; /* dismiss */
handle:
/*
* Set Resume Flag
*/
regs->eflags |= EF_RF;
/*
* Determine which breakpoint was encountered.
*/
for(i=0, bp=kdb_breakpoints; i<KDB_MAXBPT; i++, bp++) {
if (!(bp->bp_free)
&& (bp->bp_global || bp->bp_cpu == smp_processor_id())
&& (bp->bp_hard)
&& (bp->bp_hard->bph_reg == reg)) {
/*
* Hit this breakpoint.
*/
kdb_printf("%s breakpoint #%d at " kdb_bfd_vma_fmt "\n",
kdba_rwtypes[rw],
i, bp->bp_addr);
/*
* For an instruction breakpoint, disassemble
* the current instruction.
*/
if (rw == 0) {
kdb_id1(regs->rip);
}
goto handled;
}
}
unknown:
regs->eflags |= EF_RF; /* Supress further faults */
rv = KDB_DB_NOBPT; /* Cause kdb() to return */
handled:
/*
* Clear the pending exceptions.
*/
kdba_putdr6(0);
return rv;
}
int kdb_stub(struct kgdb_state *ks)
{
int error = 0;
kdb_bp_t *bp;
unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
kdb_reason_t reason = KDB_REASON_OOPS;
kdb_dbtrap_t db_result = KDB_DB_NOBPT;
int i;
if (KDB_STATE(REENTRY)) {
reason = KDB_REASON_SWITCH;
KDB_STATE_CLEAR(REENTRY);
addr = instruction_pointer(ks->linux_regs);
}
ks->pass_exception = 0;
if (atomic_read(&kgdb_setting_breakpoint))
reason = KDB_REASON_KEYBOARD;
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
reason = KDB_REASON_BREAK;
db_result = KDB_DB_BPT;
if (addr != instruction_pointer(ks->linux_regs))
kgdb_arch_set_pc(ks->linux_regs, addr);
break;
}
}
if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
if (bp->bp_free)
continue;
if (bp->bp_addr == addr) {
bp->bp_delay = 1;
bp->bp_delayed = 1;
/*
* SSBPT is set when the kernel debugger must single step a
* task in order to re-establish an instruction breakpoint
* which uses the instruction replacement mechanism. It is
* cleared by any action that removes the need to single-step
* the breakpoint.
*/
reason = KDB_REASON_BREAK;
db_result = KDB_DB_BPT;
KDB_STATE_SET(SSBPT);
break;
}
}
}
if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
ks->signo == SIGTRAP) {
reason = KDB_REASON_SSTEP;
db_result = KDB_DB_BPT;
}
/* Set initial kdb state variables */
KDB_STATE_CLEAR(KGDB_TRANS);
kdb_initial_cpu = ks->cpu;
kdb_current_task = kgdb_info[ks->cpu].task;
kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
/* Remove any breakpoints as needed by kdb and clear single step */
kdb_bp_remove();
KDB_STATE_CLEAR(DOING_SS);
KDB_STATE_CLEAR(DOING_SSB);
KDB_STATE_SET(PAGER);
/* zero out any offline cpu data */
for_each_present_cpu(i) {
if (!cpu_online(i)) {
kgdb_info[i].debuggerinfo = NULL;
kgdb_info[i].task = NULL;
}
}
if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
ks->pass_exception = 1;
KDB_FLAG_SET(CATASTROPHIC);
}
kdb_initial_cpu = ks->cpu;
if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
KDB_STATE_CLEAR(SSBPT);
KDB_STATE_CLEAR(DOING_SS);
} else {
/* Start kdb main loop */
error = kdb_main_loop(KDB_REASON_ENTER, reason,
ks->err_code, db_result, ks->linux_regs);
}
/*
* Upon exit from the kdb main loop setup break points and restart
* the system based on the requested continue state
*/
kdb_initial_cpu = -1;
kdb_current_task = NULL;
kdb_current_regs = NULL;
KDB_STATE_CLEAR(PAGER);
kdbnearsym_cleanup();
if (error == KDB_CMD_KGDB) {
if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
/*
* This inteface glue which allows kdb to transition in into
* the gdb stub. In order to do this the '?' or '' gdb serial
* packet response is processed here. And then control is
* passed to the gdbstub.
*/
if (KDB_STATE(DOING_KGDB))
gdbstub_state(ks, "?");
else
gdbstub_state(ks, "");
KDB_STATE_CLEAR(DOING_KGDB);
KDB_STATE_CLEAR(DOING_KGDB2);
}
return DBG_PASS_EVENT;
}
kdb_bp_install(ks->linux_regs);
dbg_activate_sw_breakpoints();
/* Set the exit state to a single step or a continue */
if (KDB_STATE(DOING_SS))
gdbstub_state(ks, "s");
else
gdbstub_state(ks, "c");
KDB_FLAG_CLEAR(CATASTROPHIC);
/* Invoke arch specific exception handling prior to system resume */
kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
if (ks->pass_exception)
kgdb_info[ks->cpu].ret_state = 1;
if (error == KDB_CMD_CPU) {
KDB_STATE_SET(REENTRY);
/*
* Force clear the single step bit because kdb emulates this
* differently vs the gdbstub
*/
kgdb_single_step = 0;
dbg_deactivate_sw_breakpoints();
return DBG_SWITCH_CPU_EVENT;
}
return kgdb_info[ks->cpu].ret_state;
}
static int
kdb_bc(int argc, const char **argv)
{
kdb_machreg_t addr;
kdb_bp_t *bp = NULL;
int lowbp = KDB_MAXBPT;
int highbp = 0;
int done = 0;
int i;
int diag;
int cmd; /* KDBCMD_B? */
if (strcmp(argv[0], "be") == 0) {
cmd = KDBCMD_BE;
} else if (strcmp(argv[0], "bd") == 0) {
cmd = KDBCMD_BD;
} else
cmd = KDBCMD_BC;
if (argc != 1)
return KDB_ARGCOUNT;
if (strcmp(argv[1], "*") == 0) {
lowbp = 0;
highbp = KDB_MAXBPT;
} else {
diag = kdbgetularg(argv[1], &addr);
if (diag)
return diag;
/*
* For addresses less than the maximum breakpoint number,
* assume that the breakpoint number is desired.
*/
if (addr < KDB_MAXBPT) {
bp = &kdb_breakpoints[addr];
lowbp = highbp = addr;
highbp++;
} else {
for(i=0, bp=kdb_breakpoints; i<KDB_MAXBPT; i++, bp++) {
if (bp->bp_addr == addr) {
lowbp = highbp = i;
highbp++;
break;
}
}
}
}
/*
* Now operate on the set of breakpoints matching the input
* criteria (either '*' for all, or an individual breakpoint).
*/
for(bp=&kdb_breakpoints[lowbp], i=lowbp;
i < highbp;
i++, bp++) {
if (bp->bp_free)
continue;
done++;
switch (cmd) {
case KDBCMD_BC:
if (bp->bp_hardtype)
kdba_free_hwbp(bp);
bp->bp_enabled = 0;
bp->bp_global = 0;
kdb_printf("Breakpoint %d at " kdb_bfd_vma_fmt " cleared\n",
i, bp->bp_addr);
bp->bp_addr = 0;
bp->bp_free = 1;
break;
case KDBCMD_BE:
/*
* Allocate a hardware breakpoint. If one is not
* available, don't enable the breakpoint.
*/
if (!bp->bp_template.bph_free
&& !bp->bp_hardtype) {
kdba_alloc_hwbp(bp, &diag);
if (diag) {
bp->bp_enabled = 0;
bp->bp_hardtype = 0;
kdba_free_hwbp(bp);
return diag;
}
}
bp->bp_enabled = 1;
kdb_printf("Breakpoint %d at " kdb_bfd_vma_fmt " enabled",
i, bp->bp_addr);
kdb_printf("\n");
break;
case KDBCMD_BD:
if (!bp->bp_enabled)
break;
/*
* Since this breakpoint is now disabled, we can
* give up the hardware register which is allocated
* to it.
*/
if (bp->bp_hardtype)
kdba_free_hwbp(bp);
bp->bp_enabled = 0;
kdb_printf("Breakpoint %d at " kdb_bfd_vma_fmt " disabled\n",
i, bp->bp_addr);
break;
}
if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
bp->bp_delay = 0;
KDB_STATE_CLEAR(SSBPT);
}
}
return (!done)?KDB_BPTNOTFOUND:0;
}
