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355 lines
8.9 KiB
355 lines
8.9 KiB
// 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 <[email protected]> |
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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(0, 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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