549 lines
13 KiB
C
549 lines
13 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2022-2023 Loongson Technology Corporation Limited
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*/
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#define pr_fmt(fmt) "hw-breakpoint: " fmt
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#include <linux/hw_breakpoint.h>
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#include <linux/kprobes.h>
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#include <linux/perf_event.h>
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#include <asm/hw_breakpoint.h>
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/* Breakpoint currently in use for each BRP. */
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static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[LOONGARCH_MAX_BRP]);
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/* Watchpoint currently in use for each WRP. */
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static DEFINE_PER_CPU(struct perf_event *, wp_on_reg[LOONGARCH_MAX_WRP]);
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int hw_breakpoint_slots(int type)
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{
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/*
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* We can be called early, so don't rely on
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* our static variables being initialised.
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*/
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switch (type) {
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case TYPE_INST:
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return get_num_brps();
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case TYPE_DATA:
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return get_num_wrps();
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default:
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pr_warn("unknown slot type: %d\n", type);
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return 0;
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}
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}
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#define READ_WB_REG_CASE(OFF, N, REG, T, VAL) \
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case (OFF + N): \
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LOONGARCH_CSR_WATCH_READ(N, REG, T, VAL); \
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break
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#define WRITE_WB_REG_CASE(OFF, N, REG, T, VAL) \
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case (OFF + N): \
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LOONGARCH_CSR_WATCH_WRITE(N, REG, T, VAL); \
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break
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#define GEN_READ_WB_REG_CASES(OFF, REG, T, VAL) \
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READ_WB_REG_CASE(OFF, 0, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 1, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 2, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 3, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 4, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 5, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 6, REG, T, VAL); \
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READ_WB_REG_CASE(OFF, 7, REG, T, VAL);
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#define GEN_WRITE_WB_REG_CASES(OFF, REG, T, VAL) \
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WRITE_WB_REG_CASE(OFF, 0, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 1, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 2, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 3, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 4, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 5, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 6, REG, T, VAL); \
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WRITE_WB_REG_CASE(OFF, 7, REG, T, VAL);
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static u64 read_wb_reg(int reg, int n, int t)
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{
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u64 val = 0;
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switch (reg + n) {
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GEN_READ_WB_REG_CASES(CSR_CFG_ADDR, ADDR, t, val);
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GEN_READ_WB_REG_CASES(CSR_CFG_MASK, MASK, t, val);
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GEN_READ_WB_REG_CASES(CSR_CFG_CTRL, CTRL, t, val);
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GEN_READ_WB_REG_CASES(CSR_CFG_ASID, ASID, t, val);
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default:
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pr_warn("Attempt to read from unknown breakpoint register %d\n", n);
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}
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return val;
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}
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NOKPROBE_SYMBOL(read_wb_reg);
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static void write_wb_reg(int reg, int n, int t, u64 val)
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{
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switch (reg + n) {
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GEN_WRITE_WB_REG_CASES(CSR_CFG_ADDR, ADDR, t, val);
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GEN_WRITE_WB_REG_CASES(CSR_CFG_MASK, MASK, t, val);
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GEN_WRITE_WB_REG_CASES(CSR_CFG_CTRL, CTRL, t, val);
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GEN_WRITE_WB_REG_CASES(CSR_CFG_ASID, ASID, t, val);
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default:
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pr_warn("Attempt to write to unknown breakpoint register %d\n", n);
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}
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}
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NOKPROBE_SYMBOL(write_wb_reg);
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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 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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static int hw_breakpoint_slot_setup(struct perf_event **slots, int max_slots,
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struct perf_event *bp, 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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void ptrace_hw_copy_thread(struct task_struct *tsk)
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{
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memset(tsk->thread.hbp_break, 0, sizeof(tsk->thread.hbp_break));
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memset(tsk->thread.hbp_watch, 0, sizeof(tsk->thread.hbp_watch));
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}
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/*
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* Unregister breakpoints from this task and reset the pointers in the thread_struct.
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*/
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void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
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{
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int i;
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struct thread_struct *t = &tsk->thread;
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for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
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if (t->hbp_break[i]) {
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unregister_hw_breakpoint(t->hbp_break[i]);
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t->hbp_break[i] = NULL;
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}
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}
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for (i = 0; i < LOONGARCH_MAX_WRP; i++) {
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if (t->hbp_watch[i]) {
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unregister_hw_breakpoint(t->hbp_watch[i]);
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t->hbp_watch[i] = NULL;
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}
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}
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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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u32 ctrl;
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int i, max_slots, enable;
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struct perf_event **slots;
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struct arch_hw_breakpoint *info = counter_arch_bp(bp);
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if (info->ctrl.type == LOONGARCH_BREAKPOINT_EXECUTE) {
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/* Breakpoint */
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slots = this_cpu_ptr(bp_on_reg);
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max_slots = boot_cpu_data.watch_ireg_count;
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} else {
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/* Watchpoint */
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slots = this_cpu_ptr(wp_on_reg);
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max_slots = boot_cpu_data.watch_dreg_count;
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}
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i = hw_breakpoint_slot_setup(slots, max_slots, bp, ops);
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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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/* Set the FWPnCFG/MWPnCFG 1~4 register. */
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write_wb_reg(CSR_CFG_ADDR, i, 0, info->address);
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write_wb_reg(CSR_CFG_ADDR, i, 1, info->address);
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write_wb_reg(CSR_CFG_MASK, i, 0, info->mask);
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write_wb_reg(CSR_CFG_MASK, i, 1, info->mask);
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write_wb_reg(CSR_CFG_ASID, i, 0, 0);
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write_wb_reg(CSR_CFG_ASID, i, 1, 0);
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if (info->ctrl.type == LOONGARCH_BREAKPOINT_EXECUTE) {
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write_wb_reg(CSR_CFG_CTRL, i, 0, CTRL_PLV_ENABLE);
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} else {
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ctrl = encode_ctrl_reg(info->ctrl);
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write_wb_reg(CSR_CFG_CTRL, i, 1, ctrl | CTRL_PLV_ENABLE |
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1 << MWPnCFG3_LoadEn | 1 << MWPnCFG3_StoreEn);
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}
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enable = csr_read64(LOONGARCH_CSR_CRMD);
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csr_write64(CSR_CRMD_WE | enable, LOONGARCH_CSR_CRMD);
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break;
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case HW_BREAKPOINT_UNINSTALL:
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/* Reset the FWPnCFG/MWPnCFG 1~4 register. */
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write_wb_reg(CSR_CFG_ADDR, i, 0, 0);
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write_wb_reg(CSR_CFG_ADDR, i, 1, 0);
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write_wb_reg(CSR_CFG_MASK, i, 0, 0);
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write_wb_reg(CSR_CFG_MASK, i, 1, 0);
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write_wb_reg(CSR_CFG_CTRL, i, 0, 0);
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write_wb_reg(CSR_CFG_CTRL, i, 1, 0);
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write_wb_reg(CSR_CFG_ASID, i, 0, 0);
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write_wb_reg(CSR_CFG_ASID, i, 1, 0);
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break;
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}
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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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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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{
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unsigned int len_in_bytes = 0;
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switch (hbp_len) {
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case LOONGARCH_BREAKPOINT_LEN_1:
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len_in_bytes = 1;
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break;
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case LOONGARCH_BREAKPOINT_LEN_2:
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len_in_bytes = 2;
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break;
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case LOONGARCH_BREAKPOINT_LEN_4:
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len_in_bytes = 4;
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break;
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case LOONGARCH_BREAKPOINT_LEN_8:
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len_in_bytes = 8;
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break;
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}
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return len_in_bytes;
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}
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/*
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* Check whether bp virtual address is in kernel space.
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*/
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int arch_check_bp_in_kernelspace(struct arch_hw_breakpoint *hw)
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{
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unsigned int len;
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unsigned long va;
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va = hw->address;
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len = get_hbp_len(hw->ctrl.len);
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return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
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}
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/*
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* Extract generic type and length encodings from an arch_hw_breakpoint_ctrl.
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* Hopefully this will disappear when ptrace can bypass the conversion
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* to generic breakpoint descriptions.
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*/
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int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
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int *gen_len, int *gen_type, int *offset)
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{
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/* Type */
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switch (ctrl.type) {
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case LOONGARCH_BREAKPOINT_EXECUTE:
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*gen_type = HW_BREAKPOINT_X;
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break;
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case LOONGARCH_BREAKPOINT_LOAD:
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*gen_type = HW_BREAKPOINT_R;
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break;
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case LOONGARCH_BREAKPOINT_STORE:
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*gen_type = HW_BREAKPOINT_W;
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break;
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case LOONGARCH_BREAKPOINT_LOAD | LOONGARCH_BREAKPOINT_STORE:
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*gen_type = HW_BREAKPOINT_RW;
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break;
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default:
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return -EINVAL;
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}
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if (!ctrl.len)
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return -EINVAL;
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*offset = __ffs(ctrl.len);
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/* Len */
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switch (ctrl.len) {
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case LOONGARCH_BREAKPOINT_LEN_1:
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*gen_len = HW_BREAKPOINT_LEN_1;
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break;
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case LOONGARCH_BREAKPOINT_LEN_2:
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*gen_len = HW_BREAKPOINT_LEN_2;
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break;
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case LOONGARCH_BREAKPOINT_LEN_4:
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*gen_len = HW_BREAKPOINT_LEN_4;
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break;
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case LOONGARCH_BREAKPOINT_LEN_8:
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*gen_len = HW_BREAKPOINT_LEN_8;
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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/*
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* Construct an arch_hw_breakpoint from a perf_event.
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*/
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static int arch_build_bp_info(struct perf_event *bp,
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const struct perf_event_attr *attr,
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struct arch_hw_breakpoint *hw)
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{
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/* Type */
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switch (attr->bp_type) {
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case HW_BREAKPOINT_X:
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hw->ctrl.type = LOONGARCH_BREAKPOINT_EXECUTE;
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break;
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case HW_BREAKPOINT_R:
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hw->ctrl.type = LOONGARCH_BREAKPOINT_LOAD;
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break;
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case HW_BREAKPOINT_W:
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hw->ctrl.type = LOONGARCH_BREAKPOINT_STORE;
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break;
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case HW_BREAKPOINT_RW:
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hw->ctrl.type = LOONGARCH_BREAKPOINT_LOAD | LOONGARCH_BREAKPOINT_STORE;
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break;
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default:
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return -EINVAL;
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}
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/* Len */
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switch (attr->bp_len) {
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case HW_BREAKPOINT_LEN_1:
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hw->ctrl.len = LOONGARCH_BREAKPOINT_LEN_1;
|
||
|
|
break;
|
||
|
|
case HW_BREAKPOINT_LEN_2:
|
||
|
|
hw->ctrl.len = LOONGARCH_BREAKPOINT_LEN_2;
|
||
|
|
break;
|
||
|
|
case HW_BREAKPOINT_LEN_4:
|
||
|
|
hw->ctrl.len = LOONGARCH_BREAKPOINT_LEN_4;
|
||
|
|
break;
|
||
|
|
case HW_BREAKPOINT_LEN_8:
|
||
|
|
hw->ctrl.len = LOONGARCH_BREAKPOINT_LEN_8;
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
return -EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Address */
|
||
|
|
hw->address = attr->bp_addr;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Validate the arch-specific HW Breakpoint register settings.
|
||
|
|
*/
|
||
|
|
int hw_breakpoint_arch_parse(struct perf_event *bp,
|
||
|
|
const struct perf_event_attr *attr,
|
||
|
|
struct arch_hw_breakpoint *hw)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
u64 alignment_mask, offset;
|
||
|
|
|
||
|
|
/* Build the arch_hw_breakpoint. */
|
||
|
|
ret = arch_build_bp_info(bp, attr, hw);
|
||
|
|
if (ret)
|
||
|
|
return ret;
|
||
|
|
|
||
|
|
if (hw->ctrl.type != LOONGARCH_BREAKPOINT_EXECUTE)
|
||
|
|
alignment_mask = 0x7;
|
||
|
|
offset = hw->address & alignment_mask;
|
||
|
|
|
||
|
|
hw->address &= ~alignment_mask;
|
||
|
|
hw->ctrl.len <<= offset;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void update_bp_registers(struct pt_regs *regs, int enable, int type)
|
||
|
|
{
|
||
|
|
u32 ctrl;
|
||
|
|
int i, max_slots;
|
||
|
|
struct perf_event **slots;
|
||
|
|
struct arch_hw_breakpoint *info;
|
||
|
|
|
||
|
|
switch (type) {
|
||
|
|
case 0:
|
||
|
|
slots = this_cpu_ptr(bp_on_reg);
|
||
|
|
max_slots = boot_cpu_data.watch_ireg_count;
|
||
|
|
break;
|
||
|
|
case 1:
|
||
|
|
slots = this_cpu_ptr(wp_on_reg);
|
||
|
|
max_slots = boot_cpu_data.watch_dreg_count;
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
for (i = 0; i < max_slots; ++i) {
|
||
|
|
if (!slots[i])
|
||
|
|
continue;
|
||
|
|
|
||
|
|
info = counter_arch_bp(slots[i]);
|
||
|
|
if (enable) {
|
||
|
|
if ((info->ctrl.type == LOONGARCH_BREAKPOINT_EXECUTE) && (type == 0)) {
|
||
|
|
write_wb_reg(CSR_CFG_CTRL, i, 0, CTRL_PLV_ENABLE);
|
||
|
|
write_wb_reg(CSR_CFG_CTRL, i, 0, CTRL_PLV_ENABLE);
|
||
|
|
} else {
|
||
|
|
ctrl = read_wb_reg(CSR_CFG_CTRL, i, 1);
|
||
|
|
if (info->ctrl.type == LOONGARCH_BREAKPOINT_LOAD)
|
||
|
|
ctrl |= 0x1 << MWPnCFG3_LoadEn;
|
||
|
|
if (info->ctrl.type == LOONGARCH_BREAKPOINT_STORE)
|
||
|
|
ctrl |= 0x1 << MWPnCFG3_StoreEn;
|
||
|
|
write_wb_reg(CSR_CFG_CTRL, i, 1, ctrl);
|
||
|
|
}
|
||
|
|
regs->csr_prmd |= CSR_PRMD_PWE;
|
||
|
|
} else {
|
||
|
|
if ((info->ctrl.type == LOONGARCH_BREAKPOINT_EXECUTE) && (type == 0)) {
|
||
|
|
write_wb_reg(CSR_CFG_CTRL, i, 0, 0);
|
||
|
|
} else {
|
||
|
|
ctrl = read_wb_reg(CSR_CFG_CTRL, i, 1);
|
||
|
|
if (info->ctrl.type == LOONGARCH_BREAKPOINT_LOAD)
|
||
|
|
ctrl &= ~0x1 << MWPnCFG3_LoadEn;
|
||
|
|
if (info->ctrl.type == LOONGARCH_BREAKPOINT_STORE)
|
||
|
|
ctrl &= ~0x1 << MWPnCFG3_StoreEn;
|
||
|
|
write_wb_reg(CSR_CFG_CTRL, i, 1, ctrl);
|
||
|
|
}
|
||
|
|
regs->csr_prmd &= ~CSR_PRMD_PWE;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
NOKPROBE_SYMBOL(update_bp_registers);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Debug exception handlers.
|
||
|
|
*/
|
||
|
|
void breakpoint_handler(struct pt_regs *regs)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
struct perf_event *bp, **slots;
|
||
|
|
|
||
|
|
slots = this_cpu_ptr(bp_on_reg);
|
||
|
|
|
||
|
|
for (i = 0; i < boot_cpu_data.watch_ireg_count; ++i) {
|
||
|
|
bp = slots[i];
|
||
|
|
if (bp == NULL)
|
||
|
|
continue;
|
||
|
|
perf_bp_event(bp, regs);
|
||
|
|
}
|
||
|
|
update_bp_registers(regs, 0, 0);
|
||
|
|
}
|
||
|
|
NOKPROBE_SYMBOL(breakpoint_handler);
|
||
|
|
|
||
|
|
void watchpoint_handler(struct pt_regs *regs)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
struct perf_event *wp, **slots;
|
||
|
|
|
||
|
|
slots = this_cpu_ptr(wp_on_reg);
|
||
|
|
|
||
|
|
for (i = 0; i < boot_cpu_data.watch_dreg_count; ++i) {
|
||
|
|
wp = slots[i];
|
||
|
|
if (wp == NULL)
|
||
|
|
continue;
|
||
|
|
perf_bp_event(wp, regs);
|
||
|
|
}
|
||
|
|
update_bp_registers(regs, 0, 1);
|
||
|
|
}
|
||
|
|
NOKPROBE_SYMBOL(watchpoint_handler);
|
||
|
|
|
||
|
|
static int __init arch_hw_breakpoint_init(void)
|
||
|
|
{
|
||
|
|
int cpu;
|
||
|
|
|
||
|
|
boot_cpu_data.watch_ireg_count = get_num_brps();
|
||
|
|
boot_cpu_data.watch_dreg_count = get_num_wrps();
|
||
|
|
|
||
|
|
pr_info("Found %d breakpoint and %d watchpoint registers.\n",
|
||
|
|
boot_cpu_data.watch_ireg_count, boot_cpu_data.watch_dreg_count);
|
||
|
|
|
||
|
|
for (cpu = 1; cpu < NR_CPUS; cpu++) {
|
||
|
|
cpu_data[cpu].watch_ireg_count = boot_cpu_data.watch_ireg_count;
|
||
|
|
cpu_data[cpu].watch_dreg_count = boot_cpu_data.watch_dreg_count;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
arch_initcall(arch_hw_breakpoint_init);
|
||
|
|
|
||
|
|
void hw_breakpoint_thread_switch(struct task_struct *next)
|
||
|
|
{
|
||
|
|
u64 addr, mask;
|
||
|
|
struct pt_regs *regs = task_pt_regs(next);
|
||
|
|
|
||
|
|
if (test_tsk_thread_flag(next, TIF_SINGLESTEP)) {
|
||
|
|
addr = read_wb_reg(CSR_CFG_ADDR, 0, 0);
|
||
|
|
mask = read_wb_reg(CSR_CFG_MASK, 0, 0);
|
||
|
|
if (!((regs->csr_era ^ addr) & ~mask))
|
||
|
|
csr_write32(CSR_FWPC_SKIP, LOONGARCH_CSR_FWPS);
|
||
|
|
regs->csr_prmd |= CSR_PRMD_PWE;
|
||
|
|
} else {
|
||
|
|
/* Update breakpoints */
|
||
|
|
update_bp_registers(regs, 1, 0);
|
||
|
|
/* Update watchpoints */
|
||
|
|
update_bp_registers(regs, 1, 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void hw_breakpoint_pmu_read(struct perf_event *bp)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Dummy function to register with die_notifier.
|
||
|
|
*/
|
||
|
|
int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
|
||
|
|
unsigned long val, void *data)
|
||
|
|
{
|
||
|
|
return NOTIFY_DONE;
|
||
|
|
}
|