From fe89bd2be8667d4d876329dd534dd59158e33b1f Mon Sep 17 00:00:00 2001 From: Vincent Chen Date: Thu, 16 Apr 2020 10:38:05 +0800 Subject: riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen Reviewed-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/kgdb.c | 200 +++++++++++++++++++++++++++++++++++++++++++++ arch/riscv/kernel/traps.c | 5 ++ 3 files changed, 206 insertions(+) create mode 100644 arch/riscv/kernel/kgdb.c (limited to 'arch/riscv/kernel') diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index d8bbd3207100..b355cf485671 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -51,5 +51,6 @@ ifeq ($(CONFIG_RISCV_SBI), y) obj-$(CONFIG_SMP) += cpu_ops_sbi.o endif obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o +obj-$(CONFIG_KGDB) += kgdb.o clean: diff --git a/arch/riscv/kernel/kgdb.c b/arch/riscv/kernel/kgdb.c new file mode 100644 index 000000000000..6bdc0908a5b8 --- /dev/null +++ b/arch/riscv/kernel/kgdb.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 SiFive + */ + +#include +#include +#include +#include +#include +#include +#include + +enum { + NOT_KGDB_BREAK = 0, + KGDB_SW_BREAK, + KGDB_COMPILED_BREAK, +}; + +struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { + {DBG_REG_ZERO, GDB_SIZEOF_REG, -1}, + {DBG_REG_RA, GDB_SIZEOF_REG, offsetof(struct pt_regs, ra)}, + {DBG_REG_SP, GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)}, + {DBG_REG_GP, GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)}, + {DBG_REG_TP, GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)}, + {DBG_REG_T0, GDB_SIZEOF_REG, offsetof(struct pt_regs, t0)}, + {DBG_REG_T1, GDB_SIZEOF_REG, offsetof(struct pt_regs, t1)}, + {DBG_REG_T2, GDB_SIZEOF_REG, offsetof(struct pt_regs, t2)}, + {DBG_REG_FP, GDB_SIZEOF_REG, offsetof(struct pt_regs, s0)}, + {DBG_REG_S1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)}, + {DBG_REG_A0, GDB_SIZEOF_REG, offsetof(struct pt_regs, a0)}, + {DBG_REG_A1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)}, + {DBG_REG_A2, GDB_SIZEOF_REG, offsetof(struct pt_regs, a2)}, + {DBG_REG_A3, GDB_SIZEOF_REG, offsetof(struct pt_regs, a3)}, + {DBG_REG_A4, GDB_SIZEOF_REG, offsetof(struct pt_regs, a4)}, + {DBG_REG_A5, GDB_SIZEOF_REG, offsetof(struct pt_regs, a5)}, + {DBG_REG_A6, GDB_SIZEOF_REG, offsetof(struct pt_regs, a6)}, + {DBG_REG_A7, GDB_SIZEOF_REG, offsetof(struct pt_regs, a7)}, + {DBG_REG_S2, GDB_SIZEOF_REG, offsetof(struct pt_regs, s2)}, + {DBG_REG_S3, GDB_SIZEOF_REG, offsetof(struct pt_regs, s3)}, + {DBG_REG_S4, GDB_SIZEOF_REG, offsetof(struct pt_regs, s4)}, + {DBG_REG_S5, GDB_SIZEOF_REG, offsetof(struct pt_regs, s5)}, + {DBG_REG_S6, GDB_SIZEOF_REG, offsetof(struct pt_regs, s6)}, + {DBG_REG_S7, GDB_SIZEOF_REG, offsetof(struct pt_regs, s7)}, + {DBG_REG_S8, GDB_SIZEOF_REG, offsetof(struct pt_regs, s8)}, + {DBG_REG_S9, GDB_SIZEOF_REG, offsetof(struct pt_regs, s9)}, + {DBG_REG_S10, GDB_SIZEOF_REG, offsetof(struct pt_regs, s10)}, + {DBG_REG_S11, GDB_SIZEOF_REG, offsetof(struct pt_regs, s11)}, + {DBG_REG_T3, GDB_SIZEOF_REG, offsetof(struct pt_regs, t3)}, + {DBG_REG_T4, GDB_SIZEOF_REG, offsetof(struct pt_regs, t4)}, + {DBG_REG_T5, GDB_SIZEOF_REG, offsetof(struct pt_regs, t5)}, + {DBG_REG_T6, GDB_SIZEOF_REG, offsetof(struct pt_regs, t6)}, + {DBG_REG_EPC, GDB_SIZEOF_REG, offsetof(struct pt_regs, epc)}, +}; + +char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) +{ + if (regno >= DBG_MAX_REG_NUM || regno < 0) + return NULL; + + if (dbg_reg_def[regno].offset != -1) + memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, + dbg_reg_def[regno].size); + else + memset(mem, 0, dbg_reg_def[regno].size); + return dbg_reg_def[regno].name; +} + +int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) +{ + if (regno >= DBG_MAX_REG_NUM || regno < 0) + return -EINVAL; + + if (dbg_reg_def[regno].offset != -1) + memcpy((void *)regs + dbg_reg_def[regno].offset, mem, + dbg_reg_def[regno].size); + return 0; +} + +void +sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) +{ + /* Initialize to zero */ + memset((char *)gdb_regs, 0, NUMREGBYTES); + + gdb_regs[DBG_REG_SP_OFF] = task->thread.sp; + gdb_regs[DBG_REG_FP_OFF] = task->thread.s[0]; + gdb_regs[DBG_REG_S1_OFF] = task->thread.s[1]; + gdb_regs[DBG_REG_S2_OFF] = task->thread.s[2]; + gdb_regs[DBG_REG_S3_OFF] = task->thread.s[3]; + gdb_regs[DBG_REG_S4_OFF] = task->thread.s[4]; + gdb_regs[DBG_REG_S5_OFF] = task->thread.s[5]; + gdb_regs[DBG_REG_S6_OFF] = task->thread.s[6]; + gdb_regs[DBG_REG_S7_OFF] = task->thread.s[7]; + gdb_regs[DBG_REG_S8_OFF] = task->thread.s[8]; + gdb_regs[DBG_REG_S9_OFF] = task->thread.s[10]; + gdb_regs[DBG_REG_S10_OFF] = task->thread.s[11]; + gdb_regs[DBG_REG_EPC_OFF] = task->thread.ra; +} + +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->epc = pc; +} + +static inline void kgdb_arch_update_addr(struct pt_regs *regs, + char *remcom_in_buffer) +{ + unsigned long addr; + char *ptr; + + ptr = &remcom_in_buffer[1]; + if (kgdb_hex2long(&ptr, &addr)) + regs->epc = addr; +} + +int kgdb_arch_handle_exception(int vector, int signo, int err_code, + char *remcom_in_buffer, char *remcom_out_buffer, + struct pt_regs *regs) +{ + int err = 0; + + switch (remcom_in_buffer[0]) { + case 'c': + case 'D': + case 'k': + if (remcom_in_buffer[0] == 'c') + kgdb_arch_update_addr(regs, remcom_in_buffer); + break; + default: + err = -1; + } + + return err; +} + +int kgdb_riscv_kgdbbreak(unsigned long addr) +{ + if (atomic_read(&kgdb_setting_breakpoint)) + if (addr == (unsigned long)&kgdb_compiled_break) + return KGDB_COMPILED_BREAK; + + return kgdb_has_hit_break(addr); +} + +static int kgdb_riscv_notify(struct notifier_block *self, unsigned long cmd, + void *ptr) +{ + struct die_args *args = (struct die_args *)ptr; + struct pt_regs *regs = args->regs; + unsigned long flags; + int type; + + if (user_mode(regs)) + return NOTIFY_DONE; + + type = kgdb_riscv_kgdbbreak(regs->epc); + if (type == NOT_KGDB_BREAK && cmd == DIE_TRAP) + return NOTIFY_DONE; + + local_irq_save(flags); + if (kgdb_handle_exception(1, args->signr, cmd, regs)) + return NOTIFY_DONE; + + if (type == KGDB_COMPILED_BREAK) + regs->epc += 4; + + local_irq_restore(flags); + + return NOTIFY_STOP; +} + +static struct notifier_block kgdb_notifier = { + .notifier_call = kgdb_riscv_notify, +}; + +int kgdb_arch_init(void) +{ + register_die_notifier(&kgdb_notifier); + + return 0; +} + +void kgdb_arch_exit(void) +{ + unregister_die_notifier(&kgdb_notifier); +} + +/* + * Global data + */ +#ifdef CONFIG_RISCV_ISA_C +const struct kgdb_arch arch_kgdb_ops = { + .gdb_bpt_instr = {0x02, 0x90}, /* c.ebreak */ +}; +#else +const struct kgdb_arch arch_kgdb_ops = { + .gdb_bpt_instr = {0x73, 0x00, 0x10, 0x00}, /* ebreak */ +}; +#endif diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 7f58fa53033f..5080fdf8c296 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -147,6 +147,11 @@ asmlinkage __visible void do_trap_break(struct pt_regs *regs) { if (user_mode(regs)) force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); +#ifdef CONFIG_KGDB + else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) + == NOTIFY_STOP) + return; +#endif else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) regs->epc += get_break_insn_length(regs->epc); else -- cgit v1.2.3