arm64: kernel: refactor code to install/uninstall breakpoints
Most of the code executed to install and uninstall breakpoints is common and can be factored out in a function that through a runtime operations type provides the requested implementation. This patch creates a common function that can be used to install/uninstall breakpoints and defines the set of operations that can be carried out through it. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
This commit is contained in:
Lorenzo Pieralisi
parent
1fcf7ce0c6
commit
2f04304587
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@ -169,15 +169,63 @@ static enum debug_el debug_exception_level(int privilege)
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}
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}
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/*
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* Install a perf counter breakpoint.
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enum hw_breakpoint_ops {
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HW_BREAKPOINT_INSTALL,
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HW_BREAKPOINT_UNINSTALL
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};
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/**
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* hw_breakpoint_slot_setup - Find and setup a perf slot according to
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* operations
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*
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* @slots: pointer to array of slots
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* @max_slots: max number of slots
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* @bp: perf_event to setup
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* @ops: operation to be carried out on the slot
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*
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* Return:
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* slot index on success
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* -ENOSPC if no slot is available/matches
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* -EINVAL on wrong operations parameter
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*/
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int arch_install_hw_breakpoint(struct perf_event *bp)
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static int hw_breakpoint_slot_setup(struct perf_event **slots, int max_slots,
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struct perf_event *bp,
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enum hw_breakpoint_ops ops)
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{
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int i;
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struct perf_event **slot;
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for (i = 0; i < max_slots; ++i) {
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slot = &slots[i];
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switch (ops) {
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case HW_BREAKPOINT_INSTALL:
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if (!*slot) {
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*slot = bp;
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return i;
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}
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break;
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case HW_BREAKPOINT_UNINSTALL:
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if (*slot == bp) {
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*slot = NULL;
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return i;
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}
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break;
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default:
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pr_warn_once("Unhandled hw breakpoint ops %d\n", ops);
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return -EINVAL;
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}
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}
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return -ENOSPC;
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}
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static int hw_breakpoint_control(struct perf_event *bp,
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enum hw_breakpoint_ops ops)
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{
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struct arch_hw_breakpoint *info = counter_arch_bp(bp);
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struct perf_event **slot, **slots;
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struct perf_event **slots;
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struct debug_info *debug_info = ¤t->thread.debug;
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int i, max_slots, ctrl_reg, val_reg, reg_enable;
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enum debug_el dbg_el = debug_exception_level(info->ctrl.privilege);
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u32 ctrl;
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if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
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@ -196,67 +244,53 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
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reg_enable = !debug_info->wps_disabled;
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}
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for (i = 0; i < max_slots; ++i) {
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slot = &slots[i];
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i = hw_breakpoint_slot_setup(slots, max_slots, bp, ops);
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if (!*slot) {
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*slot = bp;
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break;
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}
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if (WARN_ONCE(i < 0, "Can't find any breakpoint slot"))
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return i;
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switch (ops) {
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case HW_BREAKPOINT_INSTALL:
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/*
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* Ensure debug monitors are enabled at the correct exception
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* level.
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*/
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enable_debug_monitors(dbg_el);
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/* Setup the address register. */
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write_wb_reg(val_reg, i, info->address);
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/* Setup the control register. */
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ctrl = encode_ctrl_reg(info->ctrl);
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write_wb_reg(ctrl_reg, i,
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reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
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break;
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case HW_BREAKPOINT_UNINSTALL:
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/* Reset the control register. */
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write_wb_reg(ctrl_reg, i, 0);
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/*
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* Release the debug monitors for the correct exception
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* level.
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*/
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disable_debug_monitors(dbg_el);
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break;
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}
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if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
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return -ENOSPC;
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/* Ensure debug monitors are enabled at the correct exception level. */
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enable_debug_monitors(debug_exception_level(info->ctrl.privilege));
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/* Setup the address register. */
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write_wb_reg(val_reg, i, info->address);
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/* Setup the control register. */
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ctrl = encode_ctrl_reg(info->ctrl);
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write_wb_reg(ctrl_reg, i, reg_enable ? ctrl | 0x1 : ctrl & ~0x1);
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return 0;
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}
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/*
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* Install a perf counter breakpoint.
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*/
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int arch_install_hw_breakpoint(struct perf_event *bp)
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{
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return hw_breakpoint_control(bp, HW_BREAKPOINT_INSTALL);
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}
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void arch_uninstall_hw_breakpoint(struct perf_event *bp)
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{
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struct arch_hw_breakpoint *info = counter_arch_bp(bp);
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struct perf_event **slot, **slots;
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int i, max_slots, base;
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if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
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/* Breakpoint */
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base = AARCH64_DBG_REG_BCR;
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slots = this_cpu_ptr(bp_on_reg);
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max_slots = core_num_brps;
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} else {
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/* Watchpoint */
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base = AARCH64_DBG_REG_WCR;
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slots = this_cpu_ptr(wp_on_reg);
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max_slots = core_num_wrps;
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}
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/* Remove the breakpoint. */
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for (i = 0; i < max_slots; ++i) {
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slot = &slots[i];
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if (*slot == bp) {
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*slot = NULL;
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break;
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}
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}
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if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
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return;
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/* Reset the control register. */
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write_wb_reg(base, i, 0);
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/* Release the debug monitors for the correct exception level. */
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disable_debug_monitors(debug_exception_level(info->ctrl.privilege));
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hw_breakpoint_control(bp, HW_BREAKPOINT_UNINSTALL);
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}
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static int get_hbp_len(u8 hbp_len)
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