static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
void *addr = (void *) regs->tpc;
int ret = 0;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if (kcb->kprobe_status == KPROBE_HIT_SS) {
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
kcb->kprobe_orig_tstate_pil);
goto no_kprobe;
}
/* We have reentered the kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p);
kcb->kprobe_status = KPROBE_REENTER;
prepare_singlestep(p, regs, kcb);
return 1;
} else {
if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
goto no_kprobe;
}
p = __get_cpu_var(current_kprobe);
if (p->break_handler && p->break_handler(p, regs))
goto ss_probe;
}
goto no_kprobe;
}
p = get_kprobe(addr);
if (!p) {
if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of ours: let kernel handle it */
goto no_kprobe;
}
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
return 1;
ss_probe:
prepare_singlestep(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
void *addr = (void *) regs->tpc;
int ret = 0;
preempt_disable();
if (kprobe_running()) {
/* We *are* holding lock here, so this is safe.
* Disarm the probe we just hit, and ignore it.
*/
p = get_kprobe(addr);
if (p) {
if (kprobe_status == KPROBE_HIT_SS) {
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
current_kprobe_orig_tstate_pil);
unlock_kprobes();
goto no_kprobe;
}
/* We have reentered the kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe();
set_current_kprobe(p, regs);
p->nmissed++;
kprobe_status = KPROBE_REENTER;
prepare_singlestep(p, regs);
return 1;
} else {
p = current_kprobe;
if (p->break_handler && p->break_handler(p, regs))
goto ss_probe;
}
/* If it's not ours, can't be delete race, (we hold lock). */
goto no_kprobe;
}
lock_kprobes();
p = get_kprobe(addr);
if (!p) {
unlock_kprobes();
if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of ours: let kernel handle it */
goto no_kprobe;
}
set_current_kprobe(p, regs);
kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
return 1;
ss_probe:
prepare_singlestep(p, regs);
kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
/*
* Called with IRQs disabled. IRQs must remain disabled from that point
* all the way until processing this kprobe is complete. The current
* kprobes implementation cannot process more than one nested level of
* kprobe, and that level is reserved for user kprobe handlers, so we can't
* risk encountering a new kprobe in an interrupt handler.
*/
void __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p, *cur;
struct kprobe_ctlblk *kcb;
kcb = get_kprobe_ctlblk();
cur = kprobe_running();
#ifdef CONFIG_THUMB2_KERNEL
/*
* First look for a probe which was registered using an address with
* bit 0 set, this is the usual situation for pointers to Thumb code.
* If not found, fallback to looking for one with bit 0 clear.
*/
p = get_kprobe((kprobe_opcode_t *)(regs->ARM_pc | 1));
if (!p)
p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc);
#else /* ! CONFIG_THUMB2_KERNEL */
p = get_kprobe((kprobe_opcode_t *)regs->ARM_pc);
#endif
if (p) {
if (cur) {
/* Kprobe is pending, so we're recursing. */
switch (kcb->kprobe_status) {
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
/* A pre- or post-handler probe got us here. */
kprobes_inc_nmissed_count(p);
save_previous_kprobe(kcb);
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_REENTER;
singlestep(p, regs, kcb);
restore_previous_kprobe(kcb);
break;
default:
/* impossible cases */
BUG();
}
} else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
/* Probe hit and conditional execution check ok. */
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
* pre-handler and it returned non-zero, it prepped
* for calling the break_handler below on re-entry,
* so get out doing nothing more here.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
kcb->kprobe_status = KPROBE_HIT_SS;
singlestep(p, regs, kcb);
if (p->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
reset_current_kprobe();
}
} else {
/*
* Probe hit but conditional execution check failed,
* so just skip the instruction and continue as if
* nothing had happened.
*/
singlestep_skip(p, regs);
}
} else if (cur) {
/* We probably hit a jprobe. Call its break handler. */
if (cur->break_handler && cur->break_handler(cur, regs)) {
kcb->kprobe_status = KPROBE_HIT_SS;
singlestep(cur, regs, kcb);
if (cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
}
reset_current_kprobe();
} else {
/*
* The probe was removed and a race is in progress.
* There is nothing we can do about it. Let's restart
* the instruction. By the time we can restart, the
* real instruction will be there.
*/
}
}
/*
* Called with IRQs disabled. IRQs must remain disabled from that point
* all the way until processing this kprobe is complete. The current
* kprobes implementation cannot process more than one nested level of
* kprobe, and that level is reserved for user kprobe handlers, so we can't
* risk encountering a new kprobe in an interrupt handler.
*/
void __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p, *cur;
struct kprobe_ctlblk *kcb;
kprobe_opcode_t *addr = (kprobe_opcode_t *)regs->ARM_pc;
kcb = get_kprobe_ctlblk();
cur = kprobe_running();
p = get_kprobe(addr);
if (p) {
if (cur) {
/* Kprobe is pending, so we're recursing. */
switch (kcb->kprobe_status) {
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
/* A pre- or post-handler probe got us here. */
kprobes_inc_nmissed_count(p);
save_previous_kprobe(kcb);
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_REENTER;
singlestep(p, regs, kcb);
restore_previous_kprobe(kcb);
break;
default:
/* impossible cases */
BUG();
}
} else {
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
* pre-handler and it returned non-zero, it prepped
* for calling the break_handler below on re-entry,
* so get out doing nothing more here.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
kcb->kprobe_status = KPROBE_HIT_SS;
singlestep(p, regs, kcb);
if (p->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
reset_current_kprobe();
}
}
} else if (cur) {
/* We probably hit a jprobe. Call its break handler. */
if (cur->break_handler && cur->break_handler(cur, regs)) {
kcb->kprobe_status = KPROBE_HIT_SS;
singlestep(cur, regs, kcb);
if (cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
}
reset_current_kprobe();
} else {
/*
* The probe was removed and a race is in progress.
* There is nothing we can do about it. Let's restart
* the instruction. By the time we can restart, the
* real instruction will be there.
*/
}
}
