diff options
Diffstat (limited to 'arch/arm64/kernel/kgdb.c')
| -rw-r--r-- | arch/arm64/kernel/kgdb.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c new file mode 100644 index 000000000..4e1f983df --- /dev/null +++ b/arch/arm64/kernel/kgdb.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AArch64 KGDB support + * + * Based on arch/arm/kernel/kgdb.c + * + * Copyright (C) 2013 Cavium Inc. + * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com> + */ + +#include <linux/bug.h> +#include <linux/irq.h> +#include <linux/kdebug.h> +#include <linux/kgdb.h> +#include <linux/kprobes.h> +#include <linux/sched/task_stack.h> + +#include <asm/debug-monitors.h> +#include <asm/insn.h> +#include <asm/patching.h> +#include <asm/traps.h> + +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 cpu_context *cpu_context = &task->thread.cpu_context; + + /* Initialize to zero */ + memset((char *)gdb_regs, 0, NUMREGBYTES); + + gdb_regs[19] = cpu_context->x19; + gdb_regs[20] = cpu_context->x20; + gdb_regs[21] = cpu_context->x21; + gdb_regs[22] = cpu_context->x22; + gdb_regs[23] = cpu_context->x23; + gdb_regs[24] = cpu_context->x24; + gdb_regs[25] = cpu_context->x25; + gdb_regs[26] = cpu_context->x26; + gdb_regs[27] = cpu_context->x27; + gdb_regs[28] = cpu_context->x28; + gdb_regs[29] = cpu_context->fp; + + gdb_regs[31] = cpu_context->sp; + gdb_regs[32] = cpu_context->pc; +} + +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); + else + kernel_rewind_single_step(linux_regs); + err = 0; + break; + default: + err = -1; + } + return err; +} + +static int kgdb_brk_fn(struct pt_regs *regs, unsigned long esr) +{ + kgdb_handle_exception(1, SIGTRAP, 0, regs); + return DBG_HOOK_HANDLED; +} +NOKPROBE_SYMBOL(kgdb_brk_fn) + +static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned long esr) +{ + compiled_break = 1; + kgdb_handle_exception(1, SIGTRAP, 0, regs); + + return DBG_HOOK_HANDLED; +} +NOKPROBE_SYMBOL(kgdb_compiled_brk_fn); + +static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned long esr) +{ + if (!kgdb_single_step) + return DBG_HOOK_ERROR; + + kgdb_handle_exception(0, SIGTRAP, 0, regs); + return DBG_HOOK_HANDLED; +} +NOKPROBE_SYMBOL(kgdb_step_brk_fn); + +static struct break_hook kgdb_brkpt_hook = { + .fn = kgdb_brk_fn, + .imm = KGDB_DYN_DBG_BRK_IMM, +}; + +static struct break_hook kgdb_compiled_brkpt_hook = { + .fn = kgdb_compiled_brk_fn, + .imm = KGDB_COMPILED_DBG_BRK_IMM, +}; + +static struct step_hook kgdb_step_hook = { + .fn = kgdb_step_brk_fn +}; + +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_kernel_break_hook(&kgdb_brkpt_hook); + register_kernel_break_hook(&kgdb_compiled_brkpt_hook); + register_kernel_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_kernel_break_hook(&kgdb_brkpt_hook); + unregister_kernel_break_hook(&kgdb_compiled_brkpt_hook); + unregister_kernel_step_hook(&kgdb_step_hook); + unregister_die_notifier(&kgdb_notifier); +} + +const 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); +} |