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Diffstat (limited to 'arch/arm64/kernel/hw_breakpoint.c')
-rw-r--r--arch/arm64/kernel/hw_breakpoint.c203
1 files changed, 136 insertions, 67 deletions
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index ff516f6691e4..f17f581116fc 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -20,6 +20,7 @@
#define pr_fmt(fmt) "hw-breakpoint: " fmt
+#include <linux/cpu_pm.h>
#include <linux/errno.h>
#include <linux/hw_breakpoint.h>
#include <linux/perf_event.h>
@@ -169,15 +170,68 @@ static enum debug_el debug_exception_level(int privilege)
}
}
-/*
- * Install a perf counter breakpoint.
+enum hw_breakpoint_ops {
+ HW_BREAKPOINT_INSTALL,
+ HW_BREAKPOINT_UNINSTALL,
+ HW_BREAKPOINT_RESTORE
+};
+
+/**
+ * hw_breakpoint_slot_setup - Find and setup a perf slot according to
+ * operations
+ *
+ * @slots: pointer to array of slots
+ * @max_slots: max number of slots
+ * @bp: perf_event to setup
+ * @ops: operation to be carried out on the slot
+ *
+ * Return:
+ * slot index on success
+ * -ENOSPC if no slot is available/matches
+ * -EINVAL on wrong operations parameter
*/
-int arch_install_hw_breakpoint(struct perf_event *bp)
+static int hw_breakpoint_slot_setup(struct perf_event **slots, int max_slots,
+ struct perf_event *bp,
+ enum hw_breakpoint_ops ops)
+{
+ int i;
+ struct perf_event **slot;
+
+ for (i = 0; i < max_slots; ++i) {
+ slot = &slots[i];
+ switch (ops) {
+ case HW_BREAKPOINT_INSTALL:
+ if (!*slot) {
+ *slot = bp;
+ return i;
+ }
+ break;
+ case HW_BREAKPOINT_UNINSTALL:
+ if (*slot == bp) {
+ *slot = NULL;
+ return i;
+ }
+ break;
+ case HW_BREAKPOINT_RESTORE:
+ if (*slot == bp)
+ return i;
+ break;
+ default:
+ pr_warn_once("Unhandled hw breakpoint ops %d\n", ops);
+ return -EINVAL;
+ }
+ }
+ return -ENOSPC;
+}
+
+static int hw_breakpoint_control(struct perf_event *bp,
+ enum hw_breakpoint_ops ops)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
- struct perf_event **slot, **slots;
+ struct perf_event **slots;
struct debug_info *debug_info = &current->thread.debug;
int i, max_slots, ctrl_reg, val_reg, reg_enable;
+ enum debug_el dbg_el = debug_exception_level(info->ctrl.privilege);
u32 ctrl;
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
@@ -196,67 +250,54 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
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;
+ i = hw_breakpoint_slot_setup(slots, max_slots, bp, ops);
- /* Ensure debug monitors are enabled at the correct exception level. */
- enable_debug_monitors(debug_exception_level(info->ctrl.privilege));
+ if (WARN_ONCE(i < 0, "Can't find any breakpoint slot"))
+ return i;
- /* Setup the address register. */
- write_wb_reg(val_reg, i, info->address);
+ switch (ops) {
+ case HW_BREAKPOINT_INSTALL:
+ /*
+ * Ensure debug monitors are enabled at the correct exception
+ * level.
+ */
+ enable_debug_monitors(dbg_el);
+ /* Fall through */
+ case HW_BREAKPOINT_RESTORE:
+ /* 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);
+ break;
+ case HW_BREAKPOINT_UNINSTALL:
+ /* Reset the control register. */
+ write_wb_reg(ctrl_reg, i, 0);
- /* Setup the control register. */
- ctrl = encode_ctrl_reg(info->ctrl);
- write_wb_reg(ctrl_reg, i, reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
+ /*
+ * Release the debug monitors for the correct exception
+ * level.
+ */
+ disable_debug_monitors(dbg_el);
+ break;
+ }
return 0;
}
-void arch_uninstall_hw_breakpoint(struct perf_event *bp)
+/*
+ * 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;
- int i, max_slots, base;
-
- if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
- /* Breakpoint */
- base = AARCH64_DBG_REG_BCR;
- slots = this_cpu_ptr(bp_on_reg);
- max_slots = core_num_brps;
- } else {
- /* Watchpoint */
- base = AARCH64_DBG_REG_WCR;
- slots = this_cpu_ptr(wp_on_reg);
- max_slots = core_num_wrps;
- }
-
- /* Remove the breakpoint. */
- for (i = 0; i < max_slots; ++i) {
- slot = &slots[i];
-
- if (*slot == bp) {
- *slot = NULL;
- break;
- }
- }
-
- if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
- return;
-
- /* Reset the control register. */
- write_wb_reg(base, i, 0);
+ return hw_breakpoint_control(bp, HW_BREAKPOINT_INSTALL);
+}
- /* Release the debug monitors for the correct exception level. */
- disable_debug_monitors(debug_exception_level(info->ctrl.privilege));
+void arch_uninstall_hw_breakpoint(struct perf_event *bp)
+{
+ hw_breakpoint_control(bp, HW_BREAKPOINT_UNINSTALL);
}
static int get_hbp_len(u8 hbp_len)
@@ -806,18 +847,36 @@ void hw_breakpoint_thread_switch(struct task_struct *next)
/*
* CPU initialisation.
*/
-static void reset_ctrl_regs(void *unused)
+static void hw_breakpoint_reset(void *unused)
{
int i;
-
- for (i = 0; i < core_num_brps; ++i) {
- write_wb_reg(AARCH64_DBG_REG_BCR, i, 0UL);
- write_wb_reg(AARCH64_DBG_REG_BVR, i, 0UL);
+ struct perf_event **slots;
+ /*
+ * When a CPU goes through cold-boot, it does not have any installed
+ * slot, so it is safe to share the same function for restoring and
+ * resetting breakpoints; when a CPU is hotplugged in, it goes
+ * through the slots, which are all empty, hence it just resets control
+ * and value for debug registers.
+ * When this function is triggered on warm-boot through a CPU PM
+ * notifier some slots might be initialized; if so they are
+ * reprogrammed according to the debug slots content.
+ */
+ for (slots = this_cpu_ptr(bp_on_reg), i = 0; i < core_num_brps; ++i) {
+ if (slots[i]) {
+ hw_breakpoint_control(slots[i], HW_BREAKPOINT_RESTORE);
+ } else {
+ write_wb_reg(AARCH64_DBG_REG_BCR, i, 0UL);
+ write_wb_reg(AARCH64_DBG_REG_BVR, i, 0UL);
+ }
}
- for (i = 0; i < core_num_wrps; ++i) {
- write_wb_reg(AARCH64_DBG_REG_WCR, i, 0UL);
- write_wb_reg(AARCH64_DBG_REG_WVR, i, 0UL);
+ for (slots = this_cpu_ptr(wp_on_reg), i = 0; i < core_num_wrps; ++i) {
+ if (slots[i]) {
+ hw_breakpoint_control(slots[i], HW_BREAKPOINT_RESTORE);
+ } else {
+ write_wb_reg(AARCH64_DBG_REG_WCR, i, 0UL);
+ write_wb_reg(AARCH64_DBG_REG_WVR, i, 0UL);
+ }
}
}
@@ -827,7 +886,7 @@ static int hw_breakpoint_reset_notify(struct notifier_block *self,
{
int cpu = (long)hcpu;
if (action == CPU_ONLINE)
- smp_call_function_single(cpu, reset_ctrl_regs, NULL, 1);
+ smp_call_function_single(cpu, hw_breakpoint_reset, NULL, 1);
return NOTIFY_OK;
}
@@ -835,6 +894,14 @@ static struct notifier_block hw_breakpoint_reset_nb = {
.notifier_call = hw_breakpoint_reset_notify,
};
+#ifdef CONFIG_ARM64_CPU_SUSPEND
+extern void cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *));
+#else
+static inline void cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
+{
+}
+#endif
+
/*
* One-time initialisation.
*/
@@ -850,8 +917,8 @@ static int __init arch_hw_breakpoint_init(void)
* Reset the breakpoint resources. We assume that a halting
* debugger will leave the world in a nice state for us.
*/
- smp_call_function(reset_ctrl_regs, NULL, 1);
- reset_ctrl_regs(NULL);
+ smp_call_function(hw_breakpoint_reset, NULL, 1);
+ hw_breakpoint_reset(NULL);
/* Register debug fault handlers. */
hook_debug_fault_code(DBG_ESR_EVT_HWBP, breakpoint_handler, SIGTRAP,
@@ -861,6 +928,8 @@ static int __init arch_hw_breakpoint_init(void)
/* Register hotplug notifier. */
register_cpu_notifier(&hw_breakpoint_reset_nb);
+ /* Register cpu_suspend hw breakpoint restore hook */
+ cpu_suspend_set_dbg_restorer(hw_breakpoint_reset);
return 0;
}