/*
* Dump the debug register contents to the user.
* We can't dump our per cpu values because it
* may contain cpu wide breakpoint, something that
* doesn't belong to the current task.
*
* TODO: include non-ptrace user breakpoints (perf)
*/
void aout_dump_debugregs(struct user *dump)
{
int i;
int dr7 = 0;
struct perf_event *bp;
struct arch_hw_breakpoint *info;
struct thread_struct *thread = ¤t->thread;
for (i = 0; i < HBP_NUM; i++) {
bp = thread->ptrace_bps[i];
if (bp && !bp->attr.disabled) {
dump->u_debugreg[i] = bp->attr.bp_addr;
info = counter_arch_bp(bp);
dr7 |= encode_dr7(i, info->len, info->type);
} else {
dump->u_debugreg[i] = 0;
}
}
dump->u_debugreg[4] = 0;
dump->u_debugreg[5] = 0;
dump->u_debugreg[6] = current->thread.debugreg6;
dump->u_debugreg[7] = dr7;
}
int arch_validate_hwbkpt_settings(struct perf_event *bp)
{
int ret = -EINVAL;
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
if (!bp)
return ret;
switch (bp->attr.bp_type) {
case HW_BREAKPOINT_R:
info->type = DABR_DATA_READ;
break;
case HW_BREAKPOINT_W:
info->type = DABR_DATA_WRITE;
break;
case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
info->type = (DABR_DATA_READ | DABR_DATA_WRITE);
break;
default:
return ret;
}
info->address = bp->attr.bp_addr;
info->len = bp->attr.bp_len;
if (info->len >
(HW_BREAKPOINT_LEN - (info->address & HW_BREAKPOINT_ALIGN)))
return -EINVAL;
return 0;
}
/*
* Install a perf counter breakpoint.
*
* We seek a free debug address register and use it for this
* breakpoint. Eventually we enable it in the debug control register.
*
* Atomic: we hold the counter->ctx->lock and we only handle variables
* and registers local to this cpu.
*/
int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned long *dr7;
int i;
for (i = 0; i < HBP_NUM; i++) {
struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]);
if (!*slot) {
*slot = bp;
break;
}
}
if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
return -EBUSY;
set_debugreg(info->address, i);
__this_cpu_write(cpu_debugreg[i], info->address);
dr7 = &__get_cpu_var(cpu_dr7);
*dr7 |= encode_dr7(i, info->len, info->type);
set_debugreg(*dr7, 7);
return 0;
}
/*
* Enable/disable all of the breakpoints active at the specified
* exception level at the register level.
* This is used when single-stepping after a breakpoint exception.
*/
static void toggle_bp_registers(int reg, enum debug_el el, int enable)
{
int i, max_slots, privilege;
u32 ctrl;
struct perf_event **slots;
switch (reg) {
case AARCH64_DBG_REG_BCR:
slots = this_cpu_ptr(bp_on_reg);
max_slots = core_num_brps;
break;
case AARCH64_DBG_REG_WCR:
slots = this_cpu_ptr(wp_on_reg);
max_slots = core_num_wrps;
break;
default:
return;
}
for (i = 0; i < max_slots; ++i) {
if (!slots[i])
continue;
privilege = counter_arch_bp(slots[i])->ctrl.privilege;
if (debug_exception_level(privilege) != el)
continue;
ctrl = read_wb_reg(reg, i);
if (enable)
ctrl |= 0x1;
else
ctrl &= ~0x1;
write_wb_reg(reg, i, ctrl);
}
}
/*
* Handle single-step exceptions following a DABR hit.
*/
int __kprobes single_step_dabr_instruction(struct die_args *args)
{
struct pt_regs *regs = args->regs;
struct perf_event *bp = NULL;
struct arch_hw_breakpoint *info;
bp = current->thread.last_hit_ubp;
/*
* Check if we are single-stepping as a result of a
* previous HW Breakpoint exception
*/
if (!bp)
return NOTIFY_DONE;
info = counter_arch_bp(bp);
/*
* We shall invoke the user-defined callback function in the single
* stepping handler to confirm to 'trigger-after-execute' semantics
*/
if (!info->extraneous_interrupt)
perf_bp_event(bp, regs);
set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
current->thread.last_hit_ubp = NULL;
/*
* If the process was being single-stepped by ptrace, let the
* other single-step actions occur (e.g. generate SIGTRAP).
*/
if (test_thread_flag(TIF_SINGLESTEP))
return NOTIFY_DONE;
return NOTIFY_STOP;
}
/*
* Handle hitting a HW-breakpoint.
*/
static void ptrace_hbptriggered(struct perf_event *bp,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
siginfo_t info = {
.si_signo = SIGTRAP,
.si_errno = 0,
.si_code = TRAP_HWBKPT,
.si_addr = (void __user *)(bkpt->trigger),
};
#ifdef CONFIG_COMPAT
int i;
if (!is_compat_task())
goto send_sig;
for (i = 0; i < ARM_MAX_BRP; ++i) {
if (current->thread.debug.hbp_break[i] == bp) {
info.si_errno = (i << 1) + 1;
break;
}
}
for (i = 0; i < ARM_MAX_WRP; ++i) {
if (current->thread.debug.hbp_watch[i] == bp) {
info.si_errno = -((i << 1) + 1);
break;
}
}
send_sig:
#endif
force_sig_info(SIGTRAP, &info, current);
}
/*
* Unregister breakpoints from this task and reset the pointers in
* the thread_struct.
*/
void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
{
int i;
struct thread_struct *t = &tsk->thread;
for (i = 0; i < ARM_MAX_BRP; i++) {
if (t->debug.hbp_break[i]) {
unregister_hw_breakpoint(t->debug.hbp_break[i]);
t->debug.hbp_break[i] = NULL;
}
}
for (i = 0; i < ARM_MAX_WRP; i++) {
if (t->debug.hbp_watch[i]) {
unregister_hw_breakpoint(t->debug.hbp_watch[i]);
t->debug.hbp_watch[i] = NULL;
}
}
}
static void set_ibreak_regs(int reg, struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned long ibreakenable;
xtensa_wsr(info->address, SREG_IBREAKA + reg);
ibreakenable = xtensa_get_sr(SREG_IBREAKENABLE);
xtensa_set_sr(ibreakenable | (1 << reg), SREG_IBREAKENABLE);
}
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;
}
/*
* Validate the arch-specific HW Breakpoint register settings
*/
int arch_validate_hwbkpt_settings(struct perf_event *bp,
struct task_struct *tsk)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned int align;
int ret;
ret = arch_build_bp_info(bp);
if (ret)
return ret;
ret = -EINVAL;
switch (info->len) {
case SH_BREAKPOINT_LEN_1:
align = 0;
break;
case SH_BREAKPOINT_LEN_2:
align = 1;
break;
case SH_BREAKPOINT_LEN_4:
align = 3;
break;
case SH_BREAKPOINT_LEN_8:
align = 7;
break;
default:
return ret;
}
/*
* For kernel-addresses, either the address or symbol name can be
* specified.
*/
if (info->name)
info->address = (unsigned long)kallsyms_lookup_name(info->name);
/*
* Check that the low-order bits of the address are appropriate
* for the alignment implied by len.
*/
if (info->address & align)
return -EINVAL;
/* Check that the virtual address is in the proper range */
if (tsk) {
if (!arch_check_va_in_userspace(info->address, info->len))
return -EFAULT;
} else {
if (!arch_check_va_in_kernelspace(info->address, info->len))
return -EFAULT;
}
return 0;
}
int arch_check_bp_in_kernelspace(struct perf_event *bp)
{
unsigned int len;
unsigned long va;
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
va = info->address;
len = get_hbp_len(info->len);
return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
}
int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot = &__get_cpu_var(bp_per_reg);
*slot = bp;
if (current->thread.last_hit_ubp != bp)
set_dabr(info->address | info->type | DABR_TRANSLATION);
return 0;
}
/*
* Restores the breakpoint on the debug registers.
* Invoke this function if it is known that the execution context is
* about to change to cause loss of MSR_SE settings.
*/
void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
{
struct arch_hw_breakpoint *info;
if (likely(!tsk->thread.last_hit_ubp))
return;
info = counter_arch_bp(tsk->thread.last_hit_ubp);
regs->msr &= ~MSR_SE;
set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
tsk->thread.last_hit_ubp = NULL;
}
static int ptrace_hbp_get_ctrl(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
u32 *ctrl)
{
struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
if (IS_ERR(bp))
return PTR_ERR(bp);
*ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
return 0;
}
static void set_dbreak_regs(int reg, struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned long dbreakc = DBREAKC_MASK_MASK & -info->len;
if (info->type & XTENSA_BREAKPOINT_LOAD)
dbreakc |= DBREAKC_LOAD_MASK;
if (info->type & XTENSA_BREAKPOINT_STORE)
dbreakc |= DBREAKC_STOR_MASK;
xtensa_wsr(info->address, SREG_DBREAKA + reg);
xtensa_wsr(dbreakc, SREG_DBREAKC + reg);
}
static int arch_build_bp_info(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
info->address = bp->attr.bp_addr;
/* Type */
switch (bp->attr.bp_type) {
case HW_BREAKPOINT_W:
info->type = X86_BREAKPOINT_WRITE;
break;
case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
info->type = X86_BREAKPOINT_RW;
break;
case HW_BREAKPOINT_X:
info->type = X86_BREAKPOINT_EXECUTE;
/*
* x86 inst breakpoints need to have a specific undefined len.
* But we still need to check userspace is not trying to setup
* an unsupported length, to get a range breakpoint for example.
*/
if (bp->attr.bp_len == sizeof(long)) {
info->len = X86_BREAKPOINT_LEN_X;
return 0;
}
default:
return -EINVAL;
}
/* Len */
switch (bp->attr.bp_len) {
case HW_BREAKPOINT_LEN_1:
info->len = X86_BREAKPOINT_LEN_1;
break;
case HW_BREAKPOINT_LEN_2:
info->len = X86_BREAKPOINT_LEN_2;
break;
case HW_BREAKPOINT_LEN_4:
info->len = X86_BREAKPOINT_LEN_4;
break;
#ifdef CONFIG_X86_64
case HW_BREAKPOINT_LEN_8:
info->len = X86_BREAKPOINT_LEN_8;
break;
#endif
default:
return -EINVAL;
}
return 0;
}
static int arch_build_bp_info(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
info->address = bp->attr.bp_addr;
/* */
switch (bp->attr.bp_type) {
case HW_BREAKPOINT_W:
info->type = X86_BREAKPOINT_WRITE;
break;
case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
info->type = X86_BREAKPOINT_RW;
break;
case HW_BREAKPOINT_X:
info->type = X86_BREAKPOINT_EXECUTE;
/*
*/
if (bp->attr.bp_len == sizeof(long)) {
info->len = X86_BREAKPOINT_LEN_X;
return 0;
}
default:
return -EINVAL;
}
/* */
switch (bp->attr.bp_len) {
case HW_BREAKPOINT_LEN_1:
info->len = X86_BREAKPOINT_LEN_1;
break;
case HW_BREAKPOINT_LEN_2:
info->len = X86_BREAKPOINT_LEN_2;
break;
case HW_BREAKPOINT_LEN_4:
info->len = X86_BREAKPOINT_LEN_4;
break;
#ifdef CONFIG_X86_64
case HW_BREAKPOINT_LEN_8:
info->len = X86_BREAKPOINT_LEN_8;
break;
#endif
default:
return -EINVAL;
}
return 0;
}
/*
* Install a perf counter breakpoint.
*/
int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot, **slots;
struct debug_info *debug_info = ¤t->thread.debug;
int i, max_slots, ctrl_reg, val_reg, reg_enable;
u32 ctrl;
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
/* Breakpoint */
ctrl_reg = AARCH64_DBG_REG_BCR;
val_reg = AARCH64_DBG_REG_BVR;
slots = __get_cpu_var(bp_on_reg);
max_slots = core_num_brps;
reg_enable = !debug_info->bps_disabled;
} else {
/* Watchpoint */
ctrl_reg = AARCH64_DBG_REG_WCR;
val_reg = AARCH64_DBG_REG_WVR;
slots = __get_cpu_var(wp_on_reg);
max_slots = core_num_wrps;
reg_enable = !debug_info->wps_disabled;
}
for (i = 0; i < max_slots; ++i) {
slot = &slots[i];
if (!*slot) {
*slot = bp;
break;
}
}
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
return -ENOSPC;
/* Ensure debug monitors are enabled at the correct exception level. */
enable_debug_monitors(debug_exception_level(info->ctrl.privilege));
/* Setup the address register. */
write_wb_reg(val_reg, i, info->address);
/* Setup the control register. */
ctrl = encode_ctrl_reg(info->ctrl);
write_wb_reg(ctrl_reg, i, reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
return 0;
}
/*
* Install a perf counter breakpoint.
*
* We seek a free debug address register and use it for this
* breakpoint.
*
* Atomic: we hold the counter->ctx->lock and we only handle variables
* and registers local to this cpu.
*/
int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot = &__get_cpu_var(bp_per_reg);
*slot = bp;
/*
* Do not install DABR values if the instruction must be single-stepped.
* If so, DABR will be populated in single_step_dabr_instruction().
*/
if (current->thread.last_hit_ubp != bp)
set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
return 0;
}
static int ptrace_gethbpregs(struct task_struct *tsk, long num,
unsigned long __user *data)
{
u32 reg;
int idx, ret = 0;
struct perf_event *bp;
struct arch_hw_breakpoint_ctrl arch_ctrl;
if (num == 0) {
reg = ptrace_get_hbp_resource_info();
} else {
idx = ptrace_hbp_num_to_idx(num);
if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
ret = -EINVAL;
goto out;
}
bp = tsk->thread.debug.hbp[idx];
if (!bp) {
reg = 0;
goto put;
}
arch_ctrl = counter_arch_bp(bp)->ctrl;
/*
* Fix up the len because we may have adjusted it
* to compensate for an unaligned address.
*/
while (!(arch_ctrl.len & 0x1))
arch_ctrl.len >>= 1;
if (num & 0x1)
reg = bp->attr.bp_addr;
else
reg = encode_ctrl_reg(arch_ctrl);
}
put:
if (put_user(reg, data))
ret = -EFAULT;
out:
return ret;
}
/*
* Validate the arch-specific HW Breakpoint register settings
*/
int arch_validate_hwbkpt_settings(struct perf_event *bp)
{
int ret = -EINVAL;
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
if (!bp)
return ret;
switch (bp->attr.bp_type) {
case HW_BREAKPOINT_R:
info->type = DABR_DATA_READ;
break;
case HW_BREAKPOINT_W:
info->type = DABR_DATA_WRITE;
break;
case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
info->type = (DABR_DATA_READ | DABR_DATA_WRITE);
break;
default:
return ret;
}
info->address = bp->attr.bp_addr;
info->len = bp->attr.bp_len;
info->dabrx = DABRX_ALL;
if (bp->attr.exclude_user)
info->dabrx &= ~DABRX_USER;
if (bp->attr.exclude_kernel)
info->dabrx &= ~DABRX_KERNEL;
if (bp->attr.exclude_hv)
info->dabrx &= ~DABRX_HYP;
/*
* Since breakpoint length can be a maximum of HW_BREAKPOINT_LEN(8)
* and breakpoint addresses are aligned to nearest double-word
* HW_BREAKPOINT_ALIGN by rounding off to the lower address, the
* 'symbolsize' should satisfy the check below.
*/
if (info->len >
(HW_BREAKPOINT_LEN - (info->address & HW_BREAKPOINT_ALIGN)))
return -EINVAL;
return 0;
}
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
int i;
for (i = 0; i < sh_ubc->num_events; i++) {
struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]);
if (*slot == bp) {
*slot = NULL;
break;
}
}
if (WARN_ONCE(i == sh_ubc->num_events, "Can't find any breakpoint slot"))
return;
sh_ubc->disable(info, i);
clk_disable(sh_ubc->clk);
}
int arch_install_hw_breakpoint(struct perf_event *bp)
{
int i;
if (counter_arch_bp(bp)->type == XTENSA_BREAKPOINT_EXECUTE) {
/* Breakpoint */
i = alloc_slot(this_cpu_ptr(bp_on_reg), XCHAL_NUM_IBREAK, bp);
if (i < 0)
return i;
set_ibreak_regs(i, bp);
} else {
/* Watchpoint */
i = alloc_slot(this_cpu_ptr(wp_on_reg), XCHAL_NUM_DBREAK, bp);
if (i < 0)
return i;
set_dbreak_regs(i, bp);
}
return 0;
}
int arch_validate_hwbkpt_settings(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned int align;
int ret;
ret = arch_build_bp_info(bp);
if (ret)
return ret;
ret = -EINVAL;
switch (info->len) {
case X86_BREAKPOINT_LEN_1:
align = 0;
break;
case X86_BREAKPOINT_LEN_2:
align = 1;
break;
case X86_BREAKPOINT_LEN_4:
align = 3;
break;
#ifdef CONFIG_X86_64
case X86_BREAKPOINT_LEN_8:
align = 7;
break;
#endif
default:
return ret;
}
/*
*/
if (info->address & align)
return -EINVAL;
return 0;
}
static int arch_build_bp_info(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
info->address = bp->attr.bp_addr;
switch (bp->attr.bp_len) {
case HW_BREAKPOINT_LEN_1:
info->len = SH_BREAKPOINT_LEN_1;
break;
case HW_BREAKPOINT_LEN_2:
info->len = SH_BREAKPOINT_LEN_2;
break;
case HW_BREAKPOINT_LEN_4:
info->len = SH_BREAKPOINT_LEN_4;
break;
case HW_BREAKPOINT_LEN_8:
info->len = SH_BREAKPOINT_LEN_8;
break;
default:
return -EINVAL;
}
switch (bp->attr.bp_type) {
case HW_BREAKPOINT_R:
info->type = SH_BREAKPOINT_READ;
break;
case HW_BREAKPOINT_W:
info->type = SH_BREAKPOINT_WRITE;
break;
case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
info->type = SH_BREAKPOINT_RW;
break;
default:
return -EINVAL;
}
return 0;
}
/*
* Validate the arch-specific HW Breakpoint register settings
*/
int arch_validate_hwbkpt_settings(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned int align;
int ret;
ret = arch_build_bp_info(bp);
if (ret)
return ret;
ret = -EINVAL;
switch (info->len) {
case X86_BREAKPOINT_LEN_1:
align = 0;
break;
case X86_BREAKPOINT_LEN_2:
align = 1;
break;
case X86_BREAKPOINT_LEN_4:
align = 3;
break;
#ifdef CONFIG_X86_64
case X86_BREAKPOINT_LEN_8:
align = 7;
break;
#endif
default:
return ret;
}
/*
* Check that the low-order bits of the address are appropriate
* for the alignment implied by len.
*/
if (info->address & align)
return -EINVAL;
return 0;
}
/*
* Handle hitting a HW-breakpoint.
*/
static void ptrace_hbptriggered(struct perf_event *bp, int unused,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
long num;
int i;
siginfo_t info;
for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
if (current->thread.debug.hbp[i] == bp)
break;
num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
info.si_signo = SIGTRAP;
info.si_errno = (int)num;
info.si_code = TRAP_HWBKPT;
info.si_addr = (void __user *)(bkpt->trigger);
force_sig_info(SIGTRAP, &info, current);
}
int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
int i;
for (i = 0; i < sh_ubc->num_events; i++) {
struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]);
if (!*slot) {
*slot = bp;
break;
}
}
if (WARN_ONCE(i == sh_ubc->num_events, "Can't find any breakpoint slot"))
return -EBUSY;
clk_enable(sh_ubc->clk);
sh_ubc->enable(info, i);
return 0;
}
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
int i;
if (info->type == XTENSA_BREAKPOINT_EXECUTE) {
unsigned long ibreakenable;
/* Breakpoint */
i = free_slot(this_cpu_ptr(bp_on_reg), XCHAL_NUM_IBREAK, bp);
if (i >= 0) {
ibreakenable = xtensa_get_sr(SREG_IBREAKENABLE);
xtensa_set_sr(ibreakenable & ~(1 << i),
SREG_IBREAKENABLE);
}
} else {
/* Watchpoint */
i = free_slot(this_cpu_ptr(wp_on_reg), XCHAL_NUM_DBREAK, bp);
if (i >= 0)
xtensa_wsr(0, SREG_DBREAKC + i);
}
}
int __kprobes single_step_dabr_instruction(struct die_args *args)
{
struct pt_regs *regs = args->regs;
struct perf_event *bp = NULL;
struct arch_hw_breakpoint *bp_info;
bp = current->thread.last_hit_ubp;
if (!bp)
return NOTIFY_DONE;
bp_info = counter_arch_bp(bp);
if (!bp_info->extraneous_interrupt)
perf_bp_event(bp, regs);
set_dabr(bp_info->address | bp_info->type | DABR_TRANSLATION);
current->thread.last_hit_ubp = NULL;
if (test_thread_flag(TIF_SINGLESTEP))
return NOTIFY_DONE;
return NOTIFY_STOP;
}
/*
* Uninstall the breakpoint contained in the given counter.
*
* First we search the debug address register it uses and then we disable
* it.
*
* Atomic: we hold the counter->ctx->lock and we only handle variables
* and registers local to this cpu.
*/
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned long *dr7;
int i;
for (i = 0; i < HBP_NUM; i++) {
struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]);
if (*slot == bp) {
*slot = NULL;
break;
}
}
if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
return;
dr7 = &__get_cpu_var(cpu_dr7);
*dr7 &= ~__encode_dr7(i, info->len, info->type);
set_debugreg(*dr7, 7);
}