391 lines
11 KiB
C
391 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2020 SiFive
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*/
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#include <linux/ptrace.h>
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#include <linux/kdebug.h>
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#include <linux/bug.h>
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#include <linux/kgdb.h>
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#include <linux/irqflags.h>
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#include <linux/string.h>
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#include <asm/cacheflush.h>
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#include <asm/gdb_xml.h>
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#include <asm/parse_asm.h>
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enum {
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NOT_KGDB_BREAK = 0,
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KGDB_SW_BREAK,
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KGDB_COMPILED_BREAK,
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KGDB_SW_SINGLE_STEP
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};
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static unsigned long stepped_address;
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static unsigned int stepped_opcode;
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#if __riscv_xlen == 32
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/* C.JAL is an RV32C-only instruction */
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DECLARE_INSN(c_jal, MATCH_C_JAL, MASK_C_JAL)
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#else
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#define is_c_jal_insn(opcode) 0
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#endif
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DECLARE_INSN(jalr, MATCH_JALR, MASK_JALR)
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DECLARE_INSN(jal, MATCH_JAL, MASK_JAL)
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DECLARE_INSN(c_jr, MATCH_C_JR, MASK_C_JR)
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DECLARE_INSN(c_jalr, MATCH_C_JALR, MASK_C_JALR)
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DECLARE_INSN(c_j, MATCH_C_J, MASK_C_J)
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DECLARE_INSN(beq, MATCH_BEQ, MASK_BEQ)
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DECLARE_INSN(bne, MATCH_BNE, MASK_BNE)
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DECLARE_INSN(blt, MATCH_BLT, MASK_BLT)
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DECLARE_INSN(bge, MATCH_BGE, MASK_BGE)
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DECLARE_INSN(bltu, MATCH_BLTU, MASK_BLTU)
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DECLARE_INSN(bgeu, MATCH_BGEU, MASK_BGEU)
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DECLARE_INSN(c_beqz, MATCH_C_BEQZ, MASK_C_BEQZ)
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DECLARE_INSN(c_bnez, MATCH_C_BNEZ, MASK_C_BNEZ)
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DECLARE_INSN(sret, MATCH_SRET, MASK_SRET)
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static int decode_register_index(unsigned long opcode, int offset)
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{
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return (opcode >> offset) & 0x1F;
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}
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static int decode_register_index_short(unsigned long opcode, int offset)
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{
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return ((opcode >> offset) & 0x7) + 8;
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}
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/* Calculate the new address for after a step */
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static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
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{
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unsigned long pc = regs->epc;
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unsigned long *regs_ptr = (unsigned long *)regs;
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unsigned int rs1_num, rs2_num;
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int op_code;
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if (get_kernel_nofault(op_code, (void *)pc))
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return -EINVAL;
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if ((op_code & __INSN_LENGTH_MASK) != __INSN_LENGTH_GE_32) {
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if (is_c_jalr_insn(op_code) || is_c_jr_insn(op_code)) {
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rs1_num = decode_register_index(op_code, RVC_C2_RS1_OPOFF);
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*next_addr = regs_ptr[rs1_num];
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} else if (is_c_j_insn(op_code) || is_c_jal_insn(op_code)) {
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*next_addr = EXTRACT_RVC_J_IMM(op_code) + pc;
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} else if (is_c_beqz_insn(op_code)) {
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rs1_num = decode_register_index_short(op_code,
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RVC_C1_RS1_OPOFF);
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if (!rs1_num || regs_ptr[rs1_num] == 0)
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*next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
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else
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*next_addr = pc + 2;
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} else if (is_c_bnez_insn(op_code)) {
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rs1_num =
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decode_register_index_short(op_code, RVC_C1_RS1_OPOFF);
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if (rs1_num && regs_ptr[rs1_num] != 0)
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*next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
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else
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*next_addr = pc + 2;
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} else {
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*next_addr = pc + 2;
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}
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} else {
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if ((op_code & __INSN_OPCODE_MASK) == __INSN_BRANCH_OPCODE) {
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bool result = false;
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long imm = EXTRACT_BTYPE_IMM(op_code);
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unsigned long rs1_val = 0, rs2_val = 0;
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rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
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rs2_num = decode_register_index(op_code, RVG_RS2_OPOFF);
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if (rs1_num)
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rs1_val = regs_ptr[rs1_num];
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if (rs2_num)
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rs2_val = regs_ptr[rs2_num];
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if (is_beq_insn(op_code))
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result = (rs1_val == rs2_val) ? true : false;
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else if (is_bne_insn(op_code))
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result = (rs1_val != rs2_val) ? true : false;
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else if (is_blt_insn(op_code))
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result =
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((long)rs1_val <
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(long)rs2_val) ? true : false;
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else if (is_bge_insn(op_code))
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result =
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((long)rs1_val >=
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(long)rs2_val) ? true : false;
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else if (is_bltu_insn(op_code))
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result = (rs1_val < rs2_val) ? true : false;
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else if (is_bgeu_insn(op_code))
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result = (rs1_val >= rs2_val) ? true : false;
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if (result)
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*next_addr = imm + pc;
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else
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*next_addr = pc + 4;
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} else if (is_jal_insn(op_code)) {
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*next_addr = EXTRACT_JTYPE_IMM(op_code) + pc;
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} else if (is_jalr_insn(op_code)) {
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rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
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if (rs1_num)
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*next_addr = ((unsigned long *)regs)[rs1_num];
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*next_addr += EXTRACT_ITYPE_IMM(op_code);
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} else if (is_sret_insn(op_code)) {
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*next_addr = pc;
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} else {
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*next_addr = pc + 4;
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}
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}
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return 0;
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}
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static int do_single_step(struct pt_regs *regs)
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{
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/* Determine where the target instruction will send us to */
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unsigned long addr = 0;
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int error = get_step_address(regs, &addr);
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if (error)
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return error;
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/* Store the op code in the stepped address */
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error = get_kernel_nofault(stepped_opcode, (void *)addr);
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if (error)
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return error;
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stepped_address = addr;
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/* Replace the op code with the break instruction */
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error = copy_to_kernel_nofault((void *)stepped_address,
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arch_kgdb_ops.gdb_bpt_instr,
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BREAK_INSTR_SIZE);
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/* Flush and return */
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if (!error) {
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flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
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kgdb_single_step = 1;
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atomic_set(&kgdb_cpu_doing_single_step,
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raw_smp_processor_id());
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} else {
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stepped_address = 0;
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stepped_opcode = 0;
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}
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return error;
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}
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/* Undo a single step */
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static void undo_single_step(struct pt_regs *regs)
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{
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if (stepped_opcode != 0) {
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copy_to_kernel_nofault((void *)stepped_address,
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(void *)&stepped_opcode, BREAK_INSTR_SIZE);
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flush_icache_range(stepped_address,
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stepped_address + BREAK_INSTR_SIZE);
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}
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stepped_address = 0;
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stepped_opcode = 0;
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kgdb_single_step = 0;
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atomic_set(&kgdb_cpu_doing_single_step, -1);
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}
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struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
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{DBG_REG_ZERO, GDB_SIZEOF_REG, -1},
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{DBG_REG_RA, GDB_SIZEOF_REG, offsetof(struct pt_regs, ra)},
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{DBG_REG_SP, GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)},
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{DBG_REG_GP, GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
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{DBG_REG_TP, GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)},
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{DBG_REG_T0, GDB_SIZEOF_REG, offsetof(struct pt_regs, t0)},
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{DBG_REG_T1, GDB_SIZEOF_REG, offsetof(struct pt_regs, t1)},
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{DBG_REG_T2, GDB_SIZEOF_REG, offsetof(struct pt_regs, t2)},
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{DBG_REG_FP, GDB_SIZEOF_REG, offsetof(struct pt_regs, s0)},
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{DBG_REG_S1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
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{DBG_REG_A0, GDB_SIZEOF_REG, offsetof(struct pt_regs, a0)},
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{DBG_REG_A1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
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{DBG_REG_A2, GDB_SIZEOF_REG, offsetof(struct pt_regs, a2)},
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{DBG_REG_A3, GDB_SIZEOF_REG, offsetof(struct pt_regs, a3)},
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{DBG_REG_A4, GDB_SIZEOF_REG, offsetof(struct pt_regs, a4)},
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{DBG_REG_A5, GDB_SIZEOF_REG, offsetof(struct pt_regs, a5)},
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{DBG_REG_A6, GDB_SIZEOF_REG, offsetof(struct pt_regs, a6)},
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{DBG_REG_A7, GDB_SIZEOF_REG, offsetof(struct pt_regs, a7)},
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{DBG_REG_S2, GDB_SIZEOF_REG, offsetof(struct pt_regs, s2)},
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{DBG_REG_S3, GDB_SIZEOF_REG, offsetof(struct pt_regs, s3)},
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{DBG_REG_S4, GDB_SIZEOF_REG, offsetof(struct pt_regs, s4)},
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{DBG_REG_S5, GDB_SIZEOF_REG, offsetof(struct pt_regs, s5)},
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{DBG_REG_S6, GDB_SIZEOF_REG, offsetof(struct pt_regs, s6)},
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{DBG_REG_S7, GDB_SIZEOF_REG, offsetof(struct pt_regs, s7)},
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{DBG_REG_S8, GDB_SIZEOF_REG, offsetof(struct pt_regs, s8)},
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{DBG_REG_S9, GDB_SIZEOF_REG, offsetof(struct pt_regs, s9)},
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{DBG_REG_S10, GDB_SIZEOF_REG, offsetof(struct pt_regs, s10)},
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{DBG_REG_S11, GDB_SIZEOF_REG, offsetof(struct pt_regs, s11)},
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{DBG_REG_T3, GDB_SIZEOF_REG, offsetof(struct pt_regs, t3)},
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{DBG_REG_T4, GDB_SIZEOF_REG, offsetof(struct pt_regs, t4)},
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{DBG_REG_T5, GDB_SIZEOF_REG, offsetof(struct pt_regs, t5)},
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{DBG_REG_T6, GDB_SIZEOF_REG, offsetof(struct pt_regs, t6)},
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{DBG_REG_EPC, GDB_SIZEOF_REG, offsetof(struct pt_regs, epc)},
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{DBG_REG_STATUS, GDB_SIZEOF_REG, offsetof(struct pt_regs, status)},
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{DBG_REG_BADADDR, GDB_SIZEOF_REG, offsetof(struct pt_regs, badaddr)},
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{DBG_REG_CAUSE, GDB_SIZEOF_REG, offsetof(struct pt_regs, cause)},
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};
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char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
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{
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if (regno >= DBG_MAX_REG_NUM || regno < 0)
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return NULL;
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if (dbg_reg_def[regno].offset != -1)
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memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
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dbg_reg_def[regno].size);
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else
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memset(mem, 0, dbg_reg_def[regno].size);
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return dbg_reg_def[regno].name;
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}
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int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
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{
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if (regno >= DBG_MAX_REG_NUM || regno < 0)
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return -EINVAL;
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if (dbg_reg_def[regno].offset != -1)
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memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
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dbg_reg_def[regno].size);
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return 0;
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}
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void
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sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
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{
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/* Initialize to zero */
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memset((char *)gdb_regs, 0, NUMREGBYTES);
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gdb_regs[DBG_REG_SP_OFF] = task->thread.sp;
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gdb_regs[DBG_REG_FP_OFF] = task->thread.s[0];
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gdb_regs[DBG_REG_S1_OFF] = task->thread.s[1];
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gdb_regs[DBG_REG_S2_OFF] = task->thread.s[2];
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gdb_regs[DBG_REG_S3_OFF] = task->thread.s[3];
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gdb_regs[DBG_REG_S4_OFF] = task->thread.s[4];
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gdb_regs[DBG_REG_S5_OFF] = task->thread.s[5];
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gdb_regs[DBG_REG_S6_OFF] = task->thread.s[6];
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gdb_regs[DBG_REG_S7_OFF] = task->thread.s[7];
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gdb_regs[DBG_REG_S8_OFF] = task->thread.s[8];
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gdb_regs[DBG_REG_S9_OFF] = task->thread.s[10];
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gdb_regs[DBG_REG_S10_OFF] = task->thread.s[11];
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gdb_regs[DBG_REG_EPC_OFF] = task->thread.ra;
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}
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void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
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{
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regs->epc = pc;
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}
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void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
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char *remcom_out_buffer)
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{
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if (!strncmp(remcom_in_buffer, gdb_xfer_read_target,
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sizeof(gdb_xfer_read_target)))
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strcpy(remcom_out_buffer, riscv_gdb_stub_target_desc);
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else if (!strncmp(remcom_in_buffer, gdb_xfer_read_cpuxml,
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sizeof(gdb_xfer_read_cpuxml)))
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strcpy(remcom_out_buffer, riscv_gdb_stub_cpuxml);
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}
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static inline void kgdb_arch_update_addr(struct pt_regs *regs,
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char *remcom_in_buffer)
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{
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unsigned long addr;
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char *ptr;
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ptr = &remcom_in_buffer[1];
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if (kgdb_hex2long(&ptr, &addr))
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regs->epc = addr;
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}
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int kgdb_arch_handle_exception(int vector, int signo, int err_code,
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char *remcom_in_buffer, char *remcom_out_buffer,
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struct pt_regs *regs)
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{
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int err = 0;
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undo_single_step(regs);
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switch (remcom_in_buffer[0]) {
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case 'c':
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case 'D':
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case 'k':
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if (remcom_in_buffer[0] == 'c')
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kgdb_arch_update_addr(regs, remcom_in_buffer);
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break;
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case 's':
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kgdb_arch_update_addr(regs, remcom_in_buffer);
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err = do_single_step(regs);
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break;
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default:
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err = -1;
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}
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return err;
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}
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static int kgdb_riscv_kgdbbreak(unsigned long addr)
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{
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if (stepped_address == addr)
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return KGDB_SW_SINGLE_STEP;
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if (atomic_read(&kgdb_setting_breakpoint))
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if (addr == (unsigned long)&kgdb_compiled_break)
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return KGDB_COMPILED_BREAK;
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return kgdb_has_hit_break(addr);
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}
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static int kgdb_riscv_notify(struct notifier_block *self, unsigned long cmd,
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void *ptr)
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{
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struct die_args *args = (struct die_args *)ptr;
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struct pt_regs *regs = args->regs;
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unsigned long flags;
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int type;
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if (user_mode(regs))
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return NOTIFY_DONE;
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type = kgdb_riscv_kgdbbreak(regs->epc);
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if (type == NOT_KGDB_BREAK && cmd == DIE_TRAP)
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return NOTIFY_DONE;
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local_irq_save(flags);
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if (kgdb_handle_exception(type == KGDB_SW_SINGLE_STEP ? 0 : 1,
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args->signr, cmd, regs))
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return NOTIFY_DONE;
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if (type == KGDB_COMPILED_BREAK)
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regs->epc += 4;
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local_irq_restore(flags);
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return NOTIFY_STOP;
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}
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static struct notifier_block kgdb_notifier = {
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.notifier_call = kgdb_riscv_notify,
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};
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int kgdb_arch_init(void)
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{
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register_die_notifier(&kgdb_notifier);
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return 0;
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}
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void kgdb_arch_exit(void)
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{
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unregister_die_notifier(&kgdb_notifier);
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}
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/*
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* Global data
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*/
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#ifdef CONFIG_RISCV_ISA_C
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const struct kgdb_arch arch_kgdb_ops = {
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.gdb_bpt_instr = {0x02, 0x90}, /* c.ebreak */
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};
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#else
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const struct kgdb_arch arch_kgdb_ops = {
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.gdb_bpt_instr = {0x73, 0x00, 0x10, 0x00}, /* ebreak */
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};
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#endif
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