/**
* modify_user_hw_breakpoint - modify a user-space hardware breakpoint
* @bp: the breakpoint structure to modify
* @attr: new breakpoint attributes
* @triggered: callback to trigger when we hit the breakpoint
* @tsk: pointer to 'task_struct' of the process to which the address belongs
*/
int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
{
u64 old_addr = bp->attr.bp_addr;
u64 old_len = bp->attr.bp_len;
int old_type = bp->attr.bp_type;
int err = 0;
perf_event_disable(bp);
bp->attr.bp_addr = attr->bp_addr;
bp->attr.bp_type = attr->bp_type;
bp->attr.bp_len = attr->bp_len;
if (attr->disabled)
goto end;
err = validate_hw_breakpoint(bp);
if (!err)
perf_event_enable(bp);
if (err) {
bp->attr.bp_addr = old_addr;
bp->attr.bp_type = old_type;
bp->attr.bp_len = old_len;
if (!bp->attr.disabled)
perf_event_enable(bp);
return err;
}
end:
bp->attr.disabled = attr->disabled;
return 0;
}
static void nmi_timer_stop_cpu(int cpu)
{
struct perf_event *event = per_cpu(nmi_timer_events, cpu);
if (event && ctr_running)
perf_event_disable(event);
}
int __kprobes hw_breakpoint_handler(struct die_args *args)
{
int rc = NOTIFY_STOP;
struct perf_event *bp;
struct pt_regs *regs = args->regs;
int stepped = 1;
struct arch_hw_breakpoint *info;
unsigned int instr;
unsigned long dar = regs->dar;
set_dabr(0);
rcu_read_lock();
bp = __get_cpu_var(bp_per_reg);
if (!bp)
goto out;
info = counter_arch_bp(bp);
if (bp->overflow_handler == ptrace_triggered) {
perf_bp_event(bp, regs);
rc = NOTIFY_DONE;
goto out;
}
info->extraneous_interrupt = !((bp->attr.bp_addr <= dar) &&
(dar - bp->attr.bp_addr < bp->attr.bp_len));
if (user_mode(regs)) {
bp->ctx->task->thread.last_hit_ubp = bp;
regs->msr |= MSR_SE;
goto out;
}
stepped = 0;
instr = 0;
if (!__get_user_inatomic(instr, (unsigned int *) regs->nip))
stepped = emulate_step(regs, instr);
if (!stepped) {
WARN(1, "Unable to handle hardware breakpoint. Breakpoint at "
"0x%lx will be disabled.", info->address);
perf_event_disable(bp);
goto out;
}
if (!info->extraneous_interrupt)
perf_bp_event(bp, regs);
set_dabr(info->address | info->type | DABR_TRANSLATION);
out:
rcu_read_unlock();
return rc;
}
static void watchdog_nmi_disable(unsigned int cpu)
{
struct perf_event *event = per_cpu(watchdog_ev, cpu);
if (event) {
perf_event_disable(event);
per_cpu(watchdog_ev, cpu) = NULL;
/* should be in cleanup, but blocks oprofile */
perf_event_release_kernel(event);
}
return;
}
/**
* kvm_pmu_stop_counter - stop PMU counter
* @pmc: The PMU counter pointer
*
* If this counter has been configured to monitor some event, release it here.
*/
static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
{
u64 counter, reg;
if (pmc->perf_event) {
counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
__vcpu_sys_reg(vcpu, reg) = counter;
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
pmc->perf_event = NULL;
}
}
static void nmi_timer_shutdown(void)
{
struct perf_event *event;
int cpu;
cpuhp_remove_state(hp_online);
for_each_possible_cpu(cpu) {
event = per_cpu(nmi_timer_events, cpu);
if (!event)
continue;
perf_event_disable(event);
per_cpu(nmi_timer_events, cpu) = NULL;
perf_event_release_kernel(event);
}
}
/**
* kvm_pmu_vcpu_destroy - free perf event of PMU for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
struct kvm_pmc *pmc = &pmu->pmc[i];
if (pmc->perf_event) {
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
pmc->perf_event = NULL;
}
}
}
void watchdog_nmi_disable(unsigned int cpu)
{
struct perf_event *event = per_cpu(watchdog_ev, cpu);
if (event) {
perf_event_disable(event);
per_cpu(watchdog_ev, cpu) = NULL;
/* should be in cleanup, but blocks oprofile */
perf_event_release_kernel(event);
}
if (cpu == 0) {
/* watchdog_nmi_enable() expects this to be zero initially. */
cpu0_err = 0;
}
}
static void nmi_timer_shutdown(void)
{
struct perf_event *event;
int cpu;
cpu_notifier_register_begin();
__unregister_cpu_notifier(&nmi_timer_cpu_nb);
for_each_possible_cpu(cpu) {
event = per_cpu(nmi_timer_events, cpu);
if (!event)
continue;
perf_event_disable(event);
per_cpu(nmi_timer_events, cpu) = NULL;
perf_event_release_kernel(event);
}
cpu_notifier_register_done();
}
/*
* Handle debug exception notifications.
*/
int __kprobes hw_breakpoint_handler(struct die_args *args)
{
int rc = NOTIFY_STOP;
struct perf_event *bp;
struct pt_regs *regs = args->regs;
int stepped = 1;
struct arch_hw_breakpoint *info;
unsigned int instr;
unsigned long dar = regs->dar;
/* Disable breakpoints during exception handling */
set_dabr(0, 0);
/*
* The counter may be concurrently released but that can only
* occur from a call_rcu() path. We can then safely fetch
* the breakpoint, use its callback, touch its counter
* while we are in an rcu_read_lock() path.
*/
rcu_read_lock();
bp = __get_cpu_var(bp_per_reg);
if (!bp)
goto out;
info = counter_arch_bp(bp);
/*
* Return early after invoking user-callback function without restoring
* DABR if the breakpoint is from ptrace which always operates in
* one-shot mode. The ptrace-ed process will receive the SIGTRAP signal
* generated in do_dabr().
*/
if (bp->overflow_handler == ptrace_triggered) {
perf_bp_event(bp, regs);
rc = NOTIFY_DONE;
goto out;
}
/*
* Verify if dar lies within the address range occupied by the symbol
* being watched to filter extraneous exceptions. If it doesn't,
* we still need to single-step the instruction, but we don't
* generate an event.
*/
info->extraneous_interrupt = !((bp->attr.bp_addr <= dar) &&
(dar - bp->attr.bp_addr < bp->attr.bp_len));
/* Do not emulate user-space instructions, instead single-step them */
if (user_mode(regs)) {
current->thread.last_hit_ubp = bp;
regs->msr |= MSR_SE;
goto out;
}
stepped = 0;
instr = 0;
if (!__get_user_inatomic(instr, (unsigned int *) regs->nip))
stepped = emulate_step(regs, instr);
/*
* emulate_step() could not execute it. We've failed in reliably
* handling the hw-breakpoint. Unregister it and throw a warning
* message to let the user know about it.
*/
if (!stepped) {
WARN(1, "Unable to handle hardware breakpoint. Breakpoint at "
"0x%lx will be disabled.", info->address);
perf_event_disable(bp);
goto out;
}
/*
* As a policy, the callback is invoked in a 'trigger-after-execute'
* fashion
*/
if (!info->extraneous_interrupt)
perf_bp_event(bp, regs);
set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
out:
rcu_read_unlock();
return rc;
}
void capo_perf_event_disable(struct perf_event *pevent){
if(pevent != NULL)
perf_event_disable(pevent);
}
