return brps;
}
-int hw_breakpoint_slots(int type)
-{
- /*
- * We can be called early, so don't rely on
- * our static variables being initialised.
- */
- switch (type) {
- case TYPE_INST:
- return get_num_brps();
- case TYPE_DATA:
- return get_num_wrps();
- default:
- pr_warning("unknown slot type: %d\n", type);
- return 0;
- }
-}
-
/*
* In order to access the breakpoint/watchpoint control registers,
* we must be running in debug monitor mode. Unfortunately, we can
goto out;
}
+ /* If monitor mode is already enabled, just return. */
+ if (dscr & ARM_DSCR_MDBGEN)
+ goto out;
+
/* Write to the corresponding DSCR. */
- switch (debug_arch) {
+ switch (get_debug_arch()) {
case ARM_DEBUG_ARCH_V6:
case ARM_DEBUG_ARCH_V6_1:
ARM_DBG_WRITE(c1, 0, (dscr | ARM_DSCR_MDBGEN));
/* Check that the write made it through. */
ARM_DBG_READ(c1, 0, dscr);
- if (WARN_ONCE(!(dscr & ARM_DSCR_MDBGEN),
- "failed to enable monitor mode.")) {
+ if (!(dscr & ARM_DSCR_MDBGEN))
ret = -EPERM;
- }
out:
return ret;
}
+int hw_breakpoint_slots(int type)
+{
+ /*
+ * We can be called early, so don't rely on
+ * our static variables being initialised.
+ */
+ switch (type) {
+ case TYPE_INST:
+ return get_num_brps();
+ case TYPE_DATA:
+ return get_num_wrps();
+ default:
+ pr_warning("unknown slot type: %d\n", type);
+ return 0;
+ }
+}
+
/*
* Check if 8-bit byte-address select is available.
* This clobbers WRP 0.
if (debug_arch < ARM_DEBUG_ARCH_V7_ECP14)
goto out;
- if (enable_monitor_mode())
- goto out;
-
memset(&ctrl, 0, sizeof(ctrl));
ctrl.len = ARM_BREAKPOINT_LEN_8;
ctrl_reg = encode_ctrl_reg(ctrl);
return max_watchpoint_len;
}
-/*
- * Handler for reactivating a suspended watchpoint when the single
- * step `mismatch' breakpoint is triggered.
- */
-static void wp_single_step_handler(struct perf_event *bp, int unused,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- perf_event_enable(counter_arch_bp(bp)->suspended_wp);
- unregister_hw_breakpoint(bp);
-}
-
-static int bp_is_single_step(struct perf_event *bp)
-{
- return bp->overflow_handler == wp_single_step_handler;
-}
-
/*
* Install a perf counter breakpoint.
*/
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot, **slots;
int i, max_slots, ctrl_base, val_base, ret = 0;
+ u32 addr, ctrl;
/* Ensure that we are in monitor mode and halting mode is disabled. */
ret = enable_monitor_mode();
if (ret)
goto out;
+ addr = info->address;
+ ctrl = encode_ctrl_reg(info->ctrl) | 0x1;
+
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
/* Breakpoint */
ctrl_base = ARM_BASE_BCR;
val_base = ARM_BASE_BVR;
- slots = __get_cpu_var(bp_on_reg);
+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
max_slots = core_num_brps;
-
- if (bp_is_single_step(bp)) {
- info->ctrl.mismatch = 1;
- i = max_slots;
- slots[i] = bp;
- goto setup;
+ if (info->step_ctrl.enabled) {
+ /* Override the breakpoint data with the step data. */
+ addr = info->trigger & ~0x3;
+ ctrl = encode_ctrl_reg(info->step_ctrl);
}
} else {
/* Watchpoint */
- ctrl_base = ARM_BASE_WCR;
- val_base = ARM_BASE_WVR;
- slots = __get_cpu_var(wp_on_reg);
+ if (info->step_ctrl.enabled) {
+ /* Install into the reserved breakpoint region. */
+ ctrl_base = ARM_BASE_BCR + core_num_brps;
+ val_base = ARM_BASE_BVR + core_num_brps;
+ /* Override the watchpoint data with the step data. */
+ addr = info->trigger & ~0x3;
+ ctrl = encode_ctrl_reg(info->step_ctrl);
+ } else {
+ ctrl_base = ARM_BASE_WCR;
+ val_base = ARM_BASE_WVR;
+ }
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
max_slots = core_num_wrps;
}
goto out;
}
-setup:
/* Setup the address register. */
- write_wb_reg(val_base + i, info->address);
+ write_wb_reg(val_base + i, addr);
/* Setup the control register. */
- write_wb_reg(ctrl_base + i, encode_ctrl_reg(info->ctrl) | 0x1);
+ write_wb_reg(ctrl_base + i, ctrl);
out:
return ret;
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
/* Breakpoint */
base = ARM_BASE_BCR;
- slots = __get_cpu_var(bp_on_reg);
+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
max_slots = core_num_brps;
-
- if (bp_is_single_step(bp)) {
- i = max_slots;
- slots[i] = NULL;
- goto reset;
- }
} else {
/* Watchpoint */
- base = ARM_BASE_WCR;
- slots = __get_cpu_var(wp_on_reg);
+ if (info->step_ctrl.enabled)
+ base = ARM_BASE_BCR + core_num_brps;
+ else
+ base = ARM_BASE_WCR;
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
max_slots = core_num_wrps;
}
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
return;
-reset:
/* Reset the control register. */
write_wb_reg(base + i, 0);
}
/* Privilege */
info->ctrl.privilege = ARM_BREAKPOINT_USER;
- if (arch_check_bp_in_kernelspace(bp) && !bp_is_single_step(bp))
+ if (arch_check_bp_in_kernelspace(bp))
info->ctrl.privilege |= ARM_BREAKPOINT_PRIV;
/* Enabled? */
* Currently we rely on an overflow handler to take
* care of single-stepping the breakpoint when it fires.
* In the case of userspace breakpoints on a core with V7 debug,
- * we can use the mismatch feature as a poor-man's hardware single-step.
+ * we can use the mismatch feature as a poor-man's hardware
+ * single-step, but this only works for per-task breakpoints.
*/
if (WARN_ONCE(!bp->overflow_handler &&
- (arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_brps()),
+ (arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_brps()
+ || !bp->hw.bp_target),
"overflow handler required but none found")) {
ret = -EINVAL;
}
return ret;
}
-static void update_mismatch_flag(int idx, int flag)
+/*
+ * Enable/disable single-stepping over the breakpoint bp at address addr.
+ */
+static void enable_single_step(struct perf_event *bp, u32 addr)
{
- struct perf_event *bp = __get_cpu_var(bp_on_reg[idx]);
- struct arch_hw_breakpoint *info;
-
- if (bp == NULL)
- return;
+ struct arch_hw_breakpoint *info = counter_arch_bp(bp);
- info = counter_arch_bp(bp);
+ arch_uninstall_hw_breakpoint(bp);
+ info->step_ctrl.mismatch = 1;
+ info->step_ctrl.len = ARM_BREAKPOINT_LEN_4;
+ info->step_ctrl.type = ARM_BREAKPOINT_EXECUTE;
+ info->step_ctrl.privilege = info->ctrl.privilege;
+ info->step_ctrl.enabled = 1;
+ info->trigger = addr;
+ arch_install_hw_breakpoint(bp);
+}
- /* Update the mismatch field to enter/exit `single-step' mode */
- if (!bp->overflow_handler && info->ctrl.mismatch != flag) {
- info->ctrl.mismatch = flag;
- write_wb_reg(ARM_BASE_BCR + idx, encode_ctrl_reg(info->ctrl) | 0x1);
- }
+static void disable_single_step(struct perf_event *bp)
+{
+ arch_uninstall_hw_breakpoint(bp);
+ counter_arch_bp(bp)->step_ctrl.enabled = 0;
+ arch_install_hw_breakpoint(bp);
}
static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
{
int i;
- struct perf_event *bp, **slots = __get_cpu_var(wp_on_reg);
+ struct perf_event *wp, **slots;
struct arch_hw_breakpoint *info;
- struct perf_event_attr attr;
+
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
/* Without a disassembler, we can only handle 1 watchpoint. */
BUG_ON(core_num_wrps > 1);
- hw_breakpoint_init(&attr);
- attr.bp_addr = regs->ARM_pc & ~0x3;
- attr.bp_len = HW_BREAKPOINT_LEN_4;
- attr.bp_type = HW_BREAKPOINT_X;
-
for (i = 0; i < core_num_wrps; ++i) {
rcu_read_lock();
- if (slots[i] == NULL) {
+ wp = slots[i];
+
+ if (wp == NULL) {
rcu_read_unlock();
continue;
}
* single watchpoint, we can set the trigger to the lowest
* possible faulting address.
*/
- info = counter_arch_bp(slots[i]);
- info->trigger = slots[i]->attr.bp_addr;
+ info = counter_arch_bp(wp);
+ info->trigger = wp->attr.bp_addr;
pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);
- perf_bp_event(slots[i], regs);
+ perf_bp_event(wp, regs);
/*
* If no overflow handler is present, insert a temporary
* mismatch breakpoint so we can single-step over the
* watchpoint trigger.
*/
- if (!slots[i]->overflow_handler) {
- bp = register_user_hw_breakpoint(&attr,
- wp_single_step_handler,
- current);
- counter_arch_bp(bp)->suspended_wp = slots[i];
- perf_event_disable(slots[i]);
- }
+ if (!wp->overflow_handler)
+ enable_single_step(wp, instruction_pointer(regs));
rcu_read_unlock();
}
}
+static void watchpoint_single_step_handler(unsigned long pc)
+{
+ int i;
+ struct perf_event *wp, **slots;
+ struct arch_hw_breakpoint *info;
+
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
+
+ for (i = 0; i < core_num_reserved_brps; ++i) {
+ rcu_read_lock();
+
+ wp = slots[i];
+
+ if (wp == NULL)
+ goto unlock;
+
+ info = counter_arch_bp(wp);
+ if (!info->step_ctrl.enabled)
+ goto unlock;
+
+ /*
+ * Restore the original watchpoint if we've completed the
+ * single-step.
+ */
+ if (info->trigger != pc)
+ disable_single_step(wp);
+
+unlock:
+ rcu_read_unlock();
+ }
+}
+
static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
{
int i;
- int mismatch;
u32 ctrl_reg, val, addr;
- struct perf_event *bp, **slots = __get_cpu_var(bp_on_reg);
+ struct perf_event *bp, **slots;
struct arch_hw_breakpoint *info;
struct arch_hw_breakpoint_ctrl ctrl;
+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
+
/* The exception entry code places the amended lr in the PC. */
addr = regs->ARM_pc;
- for (i = 0; i < core_num_brps + core_num_reserved_brps; ++i) {
+ /* Check the currently installed breakpoints first. */
+ for (i = 0; i < core_num_brps; ++i) {
rcu_read_lock();
bp = slots[i];
- if (bp == NULL) {
- rcu_read_unlock();
- continue;
- }
+ if (bp == NULL)
+ goto unlock;
- mismatch = 0;
+ info = counter_arch_bp(bp);
/* Check if the breakpoint value matches. */
val = read_wb_reg(ARM_BASE_BVR + i);
if (val != (addr & ~0x3))
- goto unlock;
+ goto mismatch;
/* Possible match, check the byte address select to confirm. */
ctrl_reg = read_wb_reg(ARM_BASE_BCR + i);
decode_ctrl_reg(ctrl_reg, &ctrl);
if ((1 << (addr & 0x3)) & ctrl.len) {
- mismatch = 1;
- info = counter_arch_bp(bp);
info->trigger = addr;
- }
-
-unlock:
- if ((mismatch && !info->ctrl.mismatch) || bp_is_single_step(bp)) {
pr_debug("breakpoint fired: address = 0x%x\n", addr);
perf_bp_event(bp, regs);
+ if (!bp->overflow_handler)
+ enable_single_step(bp, addr);
+ goto unlock;
}
- update_mismatch_flag(i, mismatch);
+mismatch:
+ /* If we're stepping a breakpoint, it can now be restored. */
+ if (info->step_ctrl.enabled)
+ disable_single_step(bp);
+unlock:
rcu_read_unlock();
}
+
+ /* Handle any pending watchpoint single-step breakpoints. */
+ watchpoint_single_step_handler(addr);
}
/*
static int __init arch_hw_breakpoint_init(void)
{
- int ret = 0;
u32 dscr;
debug_arch = get_debug_arch();
if (debug_arch > ARM_DEBUG_ARCH_V7_ECP14) {
pr_info("debug architecture 0x%x unsupported.\n", debug_arch);
- ret = -ENODEV;
- goto out;
+ return 0;
}
/* Determine how many BRPs/WRPs are available. */
/* Register hotplug notifier. */
register_cpu_notifier(&dbg_reset_nb);
-out:
- return ret;
+ return 0;
}
arch_initcall(arch_hw_breakpoint_init);
git.openpandora.org / pandora-kernel.git / blobdiff