diff options
Diffstat (limited to 'arch/arm64/kernel/hw_breakpoint.c')
-rw-r--r-- | arch/arm64/kernel/hw_breakpoint.c | 221 |
1 files changed, 154 insertions, 67 deletions
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index ff516f6..bcaaac9 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 = ¤t->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]; + i = hw_breakpoint_slot_setup(slots, max_slots, bp, ops); - if (!*slot) { - *slot = bp; - break; - } - } + if (WARN_ONCE(i < 0, "Can't find any breakpoint slot")) + return i; - 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); + 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 +894,33 @@ static struct notifier_block hw_breakpoint_reset_nb = { .notifier_call = hw_breakpoint_reset_notify, }; +#ifdef CONFIG_CPU_PM +static int hw_breakpoint_cpu_pm_notify(struct notifier_block *self, + unsigned long action, + void *v) +{ + if (action == CPU_PM_EXIT) { + hw_breakpoint_reset(NULL); + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + +static struct notifier_block hw_breakpoint_cpu_pm_nb = { + .notifier_call = hw_breakpoint_cpu_pm_notify, +}; + +static void __init hw_breakpoint_pm_init(void) +{ + cpu_pm_register_notifier(&hw_breakpoint_cpu_pm_nb); +} +#else +static inline void hw_breakpoint_pm_init(void) +{ +} +#endif + /* * One-time initialisation. */ @@ -850,8 +936,8 @@ 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 +947,7 @@ static int __init arch_hw_breakpoint_init(void) /* Register hotplug notifier. */ register_cpu_notifier(&hw_breakpoint_reset_nb); + hw_breakpoint_pm_init(); return 0; } |