356 lines
8.9 KiB
C
356 lines
8.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* AArch64 KGDB support
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*
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* Based on arch/arm/kernel/kgdb.c
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*
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* Copyright (C) 2013 Cavium Inc.
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* Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
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*/
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#include <linux/bug.h>
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#include <linux/irq.h>
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#include <linux/kdebug.h>
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#include <linux/kgdb.h>
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#include <linux/kprobes.h>
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#include <linux/sched/task_stack.h>
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#include <asm/debug-monitors.h>
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#include <asm/insn.h>
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#include <asm/traps.h>
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struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
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{ "x0", 8, offsetof(struct pt_regs, regs[0])},
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{ "x1", 8, offsetof(struct pt_regs, regs[1])},
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{ "x2", 8, offsetof(struct pt_regs, regs[2])},
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{ "x3", 8, offsetof(struct pt_regs, regs[3])},
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{ "x4", 8, offsetof(struct pt_regs, regs[4])},
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{ "x5", 8, offsetof(struct pt_regs, regs[5])},
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{ "x6", 8, offsetof(struct pt_regs, regs[6])},
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{ "x7", 8, offsetof(struct pt_regs, regs[7])},
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{ "x8", 8, offsetof(struct pt_regs, regs[8])},
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{ "x9", 8, offsetof(struct pt_regs, regs[9])},
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{ "x10", 8, offsetof(struct pt_regs, regs[10])},
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{ "x11", 8, offsetof(struct pt_regs, regs[11])},
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{ "x12", 8, offsetof(struct pt_regs, regs[12])},
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{ "x13", 8, offsetof(struct pt_regs, regs[13])},
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{ "x14", 8, offsetof(struct pt_regs, regs[14])},
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{ "x15", 8, offsetof(struct pt_regs, regs[15])},
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{ "x16", 8, offsetof(struct pt_regs, regs[16])},
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{ "x17", 8, offsetof(struct pt_regs, regs[17])},
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{ "x18", 8, offsetof(struct pt_regs, regs[18])},
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{ "x19", 8, offsetof(struct pt_regs, regs[19])},
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{ "x20", 8, offsetof(struct pt_regs, regs[20])},
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{ "x21", 8, offsetof(struct pt_regs, regs[21])},
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{ "x22", 8, offsetof(struct pt_regs, regs[22])},
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{ "x23", 8, offsetof(struct pt_regs, regs[23])},
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{ "x24", 8, offsetof(struct pt_regs, regs[24])},
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{ "x25", 8, offsetof(struct pt_regs, regs[25])},
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{ "x26", 8, offsetof(struct pt_regs, regs[26])},
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{ "x27", 8, offsetof(struct pt_regs, regs[27])},
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{ "x28", 8, offsetof(struct pt_regs, regs[28])},
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{ "x29", 8, offsetof(struct pt_regs, regs[29])},
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{ "x30", 8, offsetof(struct pt_regs, regs[30])},
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{ "sp", 8, offsetof(struct pt_regs, sp)},
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{ "pc", 8, offsetof(struct pt_regs, pc)},
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/*
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* struct pt_regs thinks PSTATE is 64-bits wide but gdb remote
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* protocol disagrees. Therefore we must extract only the lower
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* 32-bits. Look for the big comment in asm/kgdb.h for more
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* detail.
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*/
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{ "pstate", 4, offsetof(struct pt_regs, pstate)
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#ifdef CONFIG_CPU_BIG_ENDIAN
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+ 4
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#endif
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},
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{ "v0", 16, -1 },
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{ "v1", 16, -1 },
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{ "v2", 16, -1 },
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{ "v3", 16, -1 },
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{ "v4", 16, -1 },
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{ "v5", 16, -1 },
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{ "v6", 16, -1 },
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{ "v7", 16, -1 },
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{ "v8", 16, -1 },
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{ "v9", 16, -1 },
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{ "v10", 16, -1 },
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{ "v11", 16, -1 },
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{ "v12", 16, -1 },
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{ "v13", 16, -1 },
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{ "v14", 16, -1 },
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{ "v15", 16, -1 },
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{ "v16", 16, -1 },
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{ "v17", 16, -1 },
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{ "v18", 16, -1 },
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{ "v19", 16, -1 },
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{ "v20", 16, -1 },
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{ "v21", 16, -1 },
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{ "v22", 16, -1 },
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{ "v23", 16, -1 },
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{ "v24", 16, -1 },
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{ "v25", 16, -1 },
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{ "v26", 16, -1 },
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{ "v27", 16, -1 },
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{ "v28", 16, -1 },
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{ "v29", 16, -1 },
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{ "v30", 16, -1 },
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{ "v31", 16, -1 },
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{ "fpsr", 4, -1 },
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{ "fpcr", 4, -1 },
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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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struct cpu_context *cpu_context = &task->thread.cpu_context;
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/* Initialize to zero */
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memset((char *)gdb_regs, 0, NUMREGBYTES);
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gdb_regs[19] = cpu_context->x19;
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gdb_regs[20] = cpu_context->x20;
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gdb_regs[21] = cpu_context->x21;
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gdb_regs[22] = cpu_context->x22;
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gdb_regs[23] = cpu_context->x23;
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gdb_regs[24] = cpu_context->x24;
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gdb_regs[25] = cpu_context->x25;
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gdb_regs[26] = cpu_context->x26;
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gdb_regs[27] = cpu_context->x27;
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gdb_regs[28] = cpu_context->x28;
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gdb_regs[29] = cpu_context->fp;
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gdb_regs[31] = cpu_context->sp;
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gdb_regs[32] = cpu_context->pc;
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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->pc = pc;
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}
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static int compiled_break;
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static 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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kgdb_arch_set_pc(regs, addr);
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else if (compiled_break == 1)
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kgdb_arch_set_pc(regs, regs->pc + 4);
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compiled_break = 0;
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}
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int kgdb_arch_handle_exception(int exception_vector, int signo,
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int err_code, char *remcom_in_buffer,
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char *remcom_out_buffer,
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struct pt_regs *linux_regs)
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{
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int err;
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switch (remcom_in_buffer[0]) {
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case 'D':
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case 'k':
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/*
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* Packet D (Detach), k (kill). No special handling
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* is required here. Handle same as c packet.
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*/
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case 'c':
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/*
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* Packet c (Continue) to continue executing.
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* Set pc to required address.
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* Try to read optional parameter and set pc.
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* If this was a compiled breakpoint, we need to move
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* to the next instruction else we will just breakpoint
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* over and over again.
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*/
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kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
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atomic_set(&kgdb_cpu_doing_single_step, -1);
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kgdb_single_step = 0;
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/*
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* Received continue command, disable single step
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*/
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if (kernel_active_single_step())
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kernel_disable_single_step();
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err = 0;
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break;
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case 's':
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/*
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* Update step address value with address passed
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* with step packet.
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* On debug exception return PC is copied to ELR
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* So just update PC.
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* If no step address is passed, resume from the address
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* pointed by PC. Do not update PC
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*/
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kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
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atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
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kgdb_single_step = 1;
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/*
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* Enable single step handling
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*/
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if (!kernel_active_single_step())
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kernel_enable_single_step(linux_regs);
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err = 0;
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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_brk_fn(struct pt_regs *regs, unsigned int esr)
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{
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kgdb_handle_exception(1, SIGTRAP, 0, regs);
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return DBG_HOOK_HANDLED;
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}
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NOKPROBE_SYMBOL(kgdb_brk_fn)
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static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr)
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{
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compiled_break = 1;
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kgdb_handle_exception(1, SIGTRAP, 0, regs);
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return DBG_HOOK_HANDLED;
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}
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NOKPROBE_SYMBOL(kgdb_compiled_brk_fn);
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static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
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{
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if (!kgdb_single_step)
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return DBG_HOOK_ERROR;
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kgdb_handle_exception(1, SIGTRAP, 0, regs);
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return DBG_HOOK_HANDLED;
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}
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NOKPROBE_SYMBOL(kgdb_step_brk_fn);
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static struct break_hook kgdb_brkpt_hook = {
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.fn = kgdb_brk_fn,
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.imm = KGDB_DYN_DBG_BRK_IMM,
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};
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static struct break_hook kgdb_compiled_brkpt_hook = {
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.fn = kgdb_compiled_brk_fn,
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.imm = KGDB_COMPILED_DBG_BRK_IMM,
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};
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static struct step_hook kgdb_step_hook = {
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.fn = kgdb_step_brk_fn
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};
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static int __kgdb_notify(struct die_args *args, unsigned long cmd)
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{
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struct pt_regs *regs = args->regs;
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if (kgdb_handle_exception(1, args->signr, cmd, regs))
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return NOTIFY_DONE;
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return NOTIFY_STOP;
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}
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static int
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kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = __kgdb_notify(ptr, cmd);
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local_irq_restore(flags);
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return ret;
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}
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static struct notifier_block kgdb_notifier = {
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.notifier_call = kgdb_notify,
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/*
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* Want to be lowest priority
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*/
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.priority = -INT_MAX,
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};
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/*
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* kgdb_arch_init - Perform any architecture specific initialization.
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* This function will handle the initialization of any architecture
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* specific callbacks.
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*/
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int kgdb_arch_init(void)
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{
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int ret = register_die_notifier(&kgdb_notifier);
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if (ret != 0)
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return ret;
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register_kernel_break_hook(&kgdb_brkpt_hook);
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register_kernel_break_hook(&kgdb_compiled_brkpt_hook);
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register_kernel_step_hook(&kgdb_step_hook);
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return 0;
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}
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/*
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* kgdb_arch_exit - Perform any architecture specific uninitalization.
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* This function will handle the uninitalization of any architecture
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* specific callbacks, for dynamic registration and unregistration.
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*/
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void kgdb_arch_exit(void)
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{
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unregister_kernel_break_hook(&kgdb_brkpt_hook);
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unregister_kernel_break_hook(&kgdb_compiled_brkpt_hook);
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unregister_kernel_step_hook(&kgdb_step_hook);
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unregister_die_notifier(&kgdb_notifier);
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}
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const struct kgdb_arch arch_kgdb_ops;
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int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
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{
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int err;
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BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE);
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err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr);
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if (err)
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return err;
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return aarch64_insn_write((void *)bpt->bpt_addr,
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(u32)AARCH64_BREAK_KGDB_DYN_DBG);
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}
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int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
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{
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return aarch64_insn_write((void *)bpt->bpt_addr,
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*(u32 *)bpt->saved_instr);
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}
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