/* * AArch64 KGDB support * * Based on arch/arm/kernel/kgdb.c * * Copyright (C) 2013 Cavium Inc. * Author: Vijaya Kumar K * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include #include #include #include #include #include #include #include struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { { "x0", 8, offsetof(struct pt_regs, regs[0])}, { "x1", 8, offsetof(struct pt_regs, regs[1])}, { "x2", 8, offsetof(struct pt_regs, regs[2])}, { "x3", 8, offsetof(struct pt_regs, regs[3])}, { "x4", 8, offsetof(struct pt_regs, regs[4])}, { "x5", 8, offsetof(struct pt_regs, regs[5])}, { "x6", 8, offsetof(struct pt_regs, regs[6])}, { "x7", 8, offsetof(struct pt_regs, regs[7])}, { "x8", 8, offsetof(struct pt_regs, regs[8])}, { "x9", 8, offsetof(struct pt_regs, regs[9])}, { "x10", 8, offsetof(struct pt_regs, regs[10])}, { "x11", 8, offsetof(struct pt_regs, regs[11])}, { "x12", 8, offsetof(struct pt_regs, regs[12])}, { "x13", 8, offsetof(struct pt_regs, regs[13])}, { "x14", 8, offsetof(struct pt_regs, regs[14])}, { "x15", 8, offsetof(struct pt_regs, regs[15])}, { "x16", 8, offsetof(struct pt_regs, regs[16])}, { "x17", 8, offsetof(struct pt_regs, regs[17])}, { "x18", 8, offsetof(struct pt_regs, regs[18])}, { "x19", 8, offsetof(struct pt_regs, regs[19])}, { "x20", 8, offsetof(struct pt_regs, regs[20])}, { "x21", 8, offsetof(struct pt_regs, regs[21])}, { "x22", 8, offsetof(struct pt_regs, regs[22])}, { "x23", 8, offsetof(struct pt_regs, regs[23])}, { "x24", 8, offsetof(struct pt_regs, regs[24])}, { "x25", 8, offsetof(struct pt_regs, regs[25])}, { "x26", 8, offsetof(struct pt_regs, regs[26])}, { "x27", 8, offsetof(struct pt_regs, regs[27])}, { "x28", 8, offsetof(struct pt_regs, regs[28])}, { "x29", 8, offsetof(struct pt_regs, regs[29])}, { "x30", 8, offsetof(struct pt_regs, regs[30])}, { "sp", 8, offsetof(struct pt_regs, sp)}, { "pc", 8, offsetof(struct pt_regs, pc)}, /* * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote * protocol disagrees. Therefore we must extract only the lower * 32-bits. Look for the big comment in asm/kgdb.h for more * detail. */ { "pstate", 4, offsetof(struct pt_regs, pstate) #ifdef CONFIG_CPU_BIG_ENDIAN + 4 #endif }, { "v0", 16, -1 }, { "v1", 16, -1 }, { "v2", 16, -1 }, { "v3", 16, -1 }, { "v4", 16, -1 }, { "v5", 16, -1 }, { "v6", 16, -1 }, { "v7", 16, -1 }, { "v8", 16, -1 }, { "v9", 16, -1 }, { "v10", 16, -1 }, { "v11", 16, -1 }, { "v12", 16, -1 }, { "v13", 16, -1 }, { "v14", 16, -1 }, { "v15", 16, -1 }, { "v16", 16, -1 }, { "v17", 16, -1 }, { "v18", 16, -1 }, { "v19", 16, -1 }, { "v20", 16, -1 }, { "v21", 16, -1 }, { "v22", 16, -1 }, { "v23", 16, -1 }, { "v24", 16, -1 }, { "v25", 16, -1 }, { "v26", 16, -1 }, { "v27", 16, -1 }, { "v28", 16, -1 }, { "v29", 16, -1 }, { "v30", 16, -1 }, { "v31", 16, -1 }, { "fpsr", 4, -1 }, { "fpcr", 4, -1 }, }; 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) { struct pt_regs *thread_regs; /* Initialize to zero */ memset((char *)gdb_regs, 0, NUMREGBYTES); thread_regs = task_pt_regs(task); memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES); /* Special case for PSTATE (check comments in asm/kgdb.h for details) */ dbg_get_reg(33, gdb_regs + GP_REG_BYTES, thread_regs); } void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) { regs->pc = pc; } static int compiled_break; static 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)) kgdb_arch_set_pc(regs, addr); else if (compiled_break == 1) kgdb_arch_set_pc(regs, regs->pc + 4); compiled_break = 0; } int kgdb_arch_handle_exception(int exception_vector, int signo, int err_code, char *remcom_in_buffer, char *remcom_out_buffer, struct pt_regs *linux_regs) { int err; switch (remcom_in_buffer[0]) { case 'D': case 'k': /* * Packet D (Detach), k (kill). No special handling * is required here. Handle same as c packet. */ case 'c': /* * Packet c (Continue) to continue executing. * Set pc to required address. * Try to read optional parameter and set pc. * If this was a compiled breakpoint, we need to move * to the next instruction else we will just breakpoint * over and over again. */ kgdb_arch_update_addr(linux_regs, remcom_in_buffer); atomic_set(&kgdb_cpu_doing_single_step, -1); kgdb_single_step = 0; /* * Received continue command, disable single step */ if (kernel_active_single_step()) kernel_disable_single_step(); err = 0; break; case 's': /* * Update step address value with address passed * with step packet. * On debug exception return PC is copied to ELR * So just update PC. * If no step address is passed, resume from the address * pointed by PC. Do not update PC */ kgdb_arch_update_addr(linux_regs, remcom_in_buffer); atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id()); kgdb_single_step = 1; /* * Enable single step handling */ if (!kernel_active_single_step()) kernel_enable_single_step(linux_regs); err = 0; break; default: err = -1; } return err; } static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) { kgdb_handle_exception(1, SIGTRAP, 0, regs); return 0; } NOKPROBE_SYMBOL(kgdb_brk_fn) static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) { compiled_break = 1; kgdb_handle_exception(1, SIGTRAP, 0, regs); return 0; } NOKPROBE_SYMBOL(kgdb_compiled_brk_fn); static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr) { if (!kgdb_single_step) return DBG_HOOK_ERROR; kgdb_handle_exception(1, SIGTRAP, 0, regs); return 0; } NOKPROBE_SYMBOL(kgdb_step_brk_fn); static struct break_hook kgdb_brkpt_hook = { .esr_mask = 0xffffffff, .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_DYN_DBG_BRK_IMM), .fn = kgdb_brk_fn }; static struct break_hook kgdb_compiled_brkpt_hook = { .esr_mask = 0xffffffff, .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_COMPILED_DBG_BRK_IMM), .fn = kgdb_compiled_brk_fn }; static struct step_hook kgdb_step_hook = { .fn = kgdb_step_brk_fn }; static void kgdb_call_nmi_hook(void *ignored) { kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); } void kgdb_roundup_cpus(unsigned long flags) { local_irq_enable(); smp_call_function(kgdb_call_nmi_hook, NULL, 0); local_irq_disable(); } static int __kgdb_notify(struct die_args *args, unsigned long cmd) { struct pt_regs *regs = args->regs; if (kgdb_handle_exception(1, args->signr, cmd, regs)) return NOTIFY_DONE; return NOTIFY_STOP; } static int kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) { unsigned long flags; int ret; local_irq_save(flags); ret = __kgdb_notify(ptr, cmd); local_irq_restore(flags); return ret; } static struct notifier_block kgdb_notifier = { .notifier_call = kgdb_notify, /* * Want to be lowest priority */ .priority = -INT_MAX, }; /* * kgdb_arch_init - Perform any architecture specific initialization. * This function will handle the initialization of any architecture * specific callbacks. */ int kgdb_arch_init(void) { int ret = register_die_notifier(&kgdb_notifier); if (ret != 0) return ret; register_break_hook(&kgdb_brkpt_hook); register_break_hook(&kgdb_compiled_brkpt_hook); register_step_hook(&kgdb_step_hook); return 0; } /* * kgdb_arch_exit - Perform any architecture specific uninitalization. * This function will handle the uninitalization of any architecture * specific callbacks, for dynamic registration and unregistration. */ void kgdb_arch_exit(void) { unregister_break_hook(&kgdb_brkpt_hook); unregister_break_hook(&kgdb_compiled_brkpt_hook); unregister_step_hook(&kgdb_step_hook); unregister_die_notifier(&kgdb_notifier); } struct kgdb_arch arch_kgdb_ops; int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) { int err; BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE); err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr); if (err) return err; return aarch64_insn_write((void *)bpt->bpt_addr, (u32)AARCH64_BREAK_KGDB_DYN_DBG); } int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) { return aarch64_insn_write((void *)bpt->bpt_addr, *(u32 *)bpt->saved_instr); }