817 строки
21 KiB
C
817 строки
21 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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*/
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/*
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* Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
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* Copyright (C) 2000-2001 VERITAS Software Corporation.
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* Copyright (C) 2002 Andi Kleen, SuSE Labs
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* Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
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* Copyright (C) 2007 MontaVista Software, Inc.
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* Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
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*/
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/****************************************************************************
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* Contributor: Lake Stevens Instrument Division$
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* Written by: Glenn Engel $
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* Updated by: Amit Kale<akale@veritas.com>
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* Updated by: Tom Rini <trini@kernel.crashing.org>
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* Updated by: Jason Wessel <jason.wessel@windriver.com>
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* Modified for 386 by Jim Kingdon, Cygnus Support.
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* Origianl kgdb, compatibility with 2.1.xx kernel by
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* David Grothe <dave@gcom.com>
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* Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
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* X86_64 changes from Andi Kleen's patch merged by Jim Houston
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*/
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#include <linux/spinlock.h>
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#include <linux/kdebug.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/ptrace.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/kgdb.h>
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#include <linux/smp.h>
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#include <linux/nmi.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/uaccess.h>
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#include <linux/memory.h>
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#include <asm/text-patching.h>
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#include <asm/debugreg.h>
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#include <asm/apicdef.h>
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#include <asm/apic.h>
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#include <asm/nmi.h>
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struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
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{
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#ifdef CONFIG_X86_32
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{ "ax", 4, offsetof(struct pt_regs, ax) },
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{ "cx", 4, offsetof(struct pt_regs, cx) },
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{ "dx", 4, offsetof(struct pt_regs, dx) },
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{ "bx", 4, offsetof(struct pt_regs, bx) },
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{ "sp", 4, offsetof(struct pt_regs, sp) },
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{ "bp", 4, offsetof(struct pt_regs, bp) },
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{ "si", 4, offsetof(struct pt_regs, si) },
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{ "di", 4, offsetof(struct pt_regs, di) },
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{ "ip", 4, offsetof(struct pt_regs, ip) },
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{ "flags", 4, offsetof(struct pt_regs, flags) },
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{ "cs", 4, offsetof(struct pt_regs, cs) },
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{ "ss", 4, offsetof(struct pt_regs, ss) },
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{ "ds", 4, offsetof(struct pt_regs, ds) },
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{ "es", 4, offsetof(struct pt_regs, es) },
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#else
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{ "ax", 8, offsetof(struct pt_regs, ax) },
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{ "bx", 8, offsetof(struct pt_regs, bx) },
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{ "cx", 8, offsetof(struct pt_regs, cx) },
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{ "dx", 8, offsetof(struct pt_regs, dx) },
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{ "si", 8, offsetof(struct pt_regs, si) },
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{ "di", 8, offsetof(struct pt_regs, di) },
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{ "bp", 8, offsetof(struct pt_regs, bp) },
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{ "sp", 8, offsetof(struct pt_regs, sp) },
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{ "r8", 8, offsetof(struct pt_regs, r8) },
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{ "r9", 8, offsetof(struct pt_regs, r9) },
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{ "r10", 8, offsetof(struct pt_regs, r10) },
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{ "r11", 8, offsetof(struct pt_regs, r11) },
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{ "r12", 8, offsetof(struct pt_regs, r12) },
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{ "r13", 8, offsetof(struct pt_regs, r13) },
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{ "r14", 8, offsetof(struct pt_regs, r14) },
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{ "r15", 8, offsetof(struct pt_regs, r15) },
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{ "ip", 8, offsetof(struct pt_regs, ip) },
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{ "flags", 4, offsetof(struct pt_regs, flags) },
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{ "cs", 4, offsetof(struct pt_regs, cs) },
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{ "ss", 4, offsetof(struct pt_regs, ss) },
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{ "ds", 4, -1 },
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{ "es", 4, -1 },
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#endif
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{ "fs", 4, -1 },
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{ "gs", 4, -1 },
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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 (
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#ifdef CONFIG_X86_32
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regno == GDB_SS || regno == GDB_FS || regno == GDB_GS ||
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#endif
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regno == GDB_SP || regno == GDB_ORIG_AX)
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return 0;
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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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char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
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{
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if (regno == GDB_ORIG_AX) {
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memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax));
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return "orig_ax";
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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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#ifdef CONFIG_X86_32
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switch (regno) {
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case GDB_SS:
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if (!user_mode(regs))
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*(unsigned long *)mem = __KERNEL_DS;
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break;
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case GDB_SP:
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if (!user_mode(regs))
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*(unsigned long *)mem = kernel_stack_pointer(regs);
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break;
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case GDB_GS:
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case GDB_FS:
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*(unsigned long *)mem = 0xFFFF;
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break;
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}
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#endif
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return dbg_reg_def[regno].name;
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}
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/**
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* sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
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* @gdb_regs: A pointer to hold the registers in the order GDB wants.
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* @p: The &struct task_struct of the desired process.
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*
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* Convert the register values of the sleeping process in @p to
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* the format that GDB expects.
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* This function is called when kgdb does not have access to the
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* &struct pt_regs and therefore it should fill the gdb registers
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* @gdb_regs with what has been saved in &struct thread_struct
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* thread field during switch_to.
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*/
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void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
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{
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#ifndef CONFIG_X86_32
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u32 *gdb_regs32 = (u32 *)gdb_regs;
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#endif
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gdb_regs[GDB_AX] = 0;
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gdb_regs[GDB_BX] = 0;
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gdb_regs[GDB_CX] = 0;
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gdb_regs[GDB_DX] = 0;
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gdb_regs[GDB_SI] = 0;
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gdb_regs[GDB_DI] = 0;
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gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp;
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#ifdef CONFIG_X86_32
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gdb_regs[GDB_DS] = __KERNEL_DS;
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gdb_regs[GDB_ES] = __KERNEL_DS;
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gdb_regs[GDB_PS] = 0;
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gdb_regs[GDB_CS] = __KERNEL_CS;
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gdb_regs[GDB_PC] = p->thread.ip;
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gdb_regs[GDB_SS] = __KERNEL_DS;
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gdb_regs[GDB_FS] = 0xFFFF;
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gdb_regs[GDB_GS] = 0xFFFF;
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#else
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gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8);
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gdb_regs32[GDB_CS] = __KERNEL_CS;
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gdb_regs32[GDB_SS] = __KERNEL_DS;
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gdb_regs[GDB_PC] = 0;
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gdb_regs[GDB_R8] = 0;
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gdb_regs[GDB_R9] = 0;
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gdb_regs[GDB_R10] = 0;
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gdb_regs[GDB_R11] = 0;
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gdb_regs[GDB_R12] = 0;
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gdb_regs[GDB_R13] = 0;
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gdb_regs[GDB_R14] = 0;
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gdb_regs[GDB_R15] = 0;
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#endif
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gdb_regs[GDB_SP] = p->thread.sp;
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}
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static struct hw_breakpoint {
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unsigned enabled;
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unsigned long addr;
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int len;
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int type;
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struct perf_event * __percpu *pev;
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} breakinfo[HBP_NUM];
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static unsigned long early_dr7;
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static void kgdb_correct_hw_break(void)
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{
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int breakno;
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for (breakno = 0; breakno < HBP_NUM; breakno++) {
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struct perf_event *bp;
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struct arch_hw_breakpoint *info;
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int val;
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int cpu = raw_smp_processor_id();
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if (!breakinfo[breakno].enabled)
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continue;
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if (dbg_is_early) {
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set_debugreg(breakinfo[breakno].addr, breakno);
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early_dr7 |= encode_dr7(breakno,
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breakinfo[breakno].len,
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breakinfo[breakno].type);
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set_debugreg(early_dr7, 7);
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continue;
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}
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bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
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info = counter_arch_bp(bp);
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if (bp->attr.disabled != 1)
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continue;
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bp->attr.bp_addr = breakinfo[breakno].addr;
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bp->attr.bp_len = breakinfo[breakno].len;
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bp->attr.bp_type = breakinfo[breakno].type;
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info->address = breakinfo[breakno].addr;
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info->len = breakinfo[breakno].len;
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info->type = breakinfo[breakno].type;
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val = arch_install_hw_breakpoint(bp);
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if (!val)
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bp->attr.disabled = 0;
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}
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if (!dbg_is_early)
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hw_breakpoint_restore();
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}
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static int hw_break_reserve_slot(int breakno)
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{
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int cpu;
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int cnt = 0;
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struct perf_event **pevent;
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if (dbg_is_early)
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return 0;
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for_each_online_cpu(cpu) {
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cnt++;
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pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
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if (dbg_reserve_bp_slot(*pevent))
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goto fail;
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}
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return 0;
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fail:
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for_each_online_cpu(cpu) {
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cnt--;
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if (!cnt)
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break;
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pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
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dbg_release_bp_slot(*pevent);
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}
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return -1;
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}
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static int hw_break_release_slot(int breakno)
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{
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struct perf_event **pevent;
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int cpu;
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if (dbg_is_early)
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return 0;
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for_each_online_cpu(cpu) {
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pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
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if (dbg_release_bp_slot(*pevent))
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/*
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* The debugger is responsible for handing the retry on
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* remove failure.
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*/
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return -1;
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}
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return 0;
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}
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static int
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kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
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{
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int i;
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for (i = 0; i < HBP_NUM; i++)
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if (breakinfo[i].addr == addr && breakinfo[i].enabled)
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break;
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if (i == HBP_NUM)
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return -1;
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if (hw_break_release_slot(i)) {
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printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
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return -1;
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}
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breakinfo[i].enabled = 0;
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return 0;
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}
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static void kgdb_remove_all_hw_break(void)
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{
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int i;
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int cpu = raw_smp_processor_id();
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struct perf_event *bp;
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for (i = 0; i < HBP_NUM; i++) {
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if (!breakinfo[i].enabled)
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continue;
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bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
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if (!bp->attr.disabled) {
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arch_uninstall_hw_breakpoint(bp);
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bp->attr.disabled = 1;
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continue;
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}
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if (dbg_is_early)
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early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
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breakinfo[i].type);
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else if (hw_break_release_slot(i))
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printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n",
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breakinfo[i].addr);
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breakinfo[i].enabled = 0;
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}
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}
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static int
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kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
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{
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int i;
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for (i = 0; i < HBP_NUM; i++)
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if (!breakinfo[i].enabled)
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break;
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if (i == HBP_NUM)
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return -1;
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switch (bptype) {
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case BP_HARDWARE_BREAKPOINT:
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len = 1;
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breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
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break;
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case BP_WRITE_WATCHPOINT:
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breakinfo[i].type = X86_BREAKPOINT_WRITE;
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break;
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case BP_ACCESS_WATCHPOINT:
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breakinfo[i].type = X86_BREAKPOINT_RW;
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break;
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default:
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return -1;
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}
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switch (len) {
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case 1:
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breakinfo[i].len = X86_BREAKPOINT_LEN_1;
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break;
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case 2:
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breakinfo[i].len = X86_BREAKPOINT_LEN_2;
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break;
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case 4:
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breakinfo[i].len = X86_BREAKPOINT_LEN_4;
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break;
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#ifdef CONFIG_X86_64
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case 8:
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breakinfo[i].len = X86_BREAKPOINT_LEN_8;
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break;
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#endif
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default:
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return -1;
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}
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breakinfo[i].addr = addr;
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if (hw_break_reserve_slot(i)) {
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breakinfo[i].addr = 0;
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return -1;
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}
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breakinfo[i].enabled = 1;
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return 0;
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}
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/**
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* kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
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* @regs: Current &struct pt_regs.
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*
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* This function will be called if the particular architecture must
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* disable hardware debugging while it is processing gdb packets or
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* handling exception.
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*/
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static void kgdb_disable_hw_debug(struct pt_regs *regs)
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{
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int i;
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int cpu = raw_smp_processor_id();
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struct perf_event *bp;
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/* Disable hardware debugging while we are in kgdb: */
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set_debugreg(0UL, 7);
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for (i = 0; i < HBP_NUM; i++) {
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if (!breakinfo[i].enabled)
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continue;
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if (dbg_is_early) {
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early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
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breakinfo[i].type);
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continue;
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}
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bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
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if (bp->attr.disabled == 1)
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continue;
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arch_uninstall_hw_breakpoint(bp);
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bp->attr.disabled = 1;
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}
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}
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#ifdef CONFIG_SMP
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/**
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* kgdb_roundup_cpus - Get other CPUs into a holding pattern
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* @flags: Current IRQ state
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*
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* On SMP systems, we need to get the attention of the other CPUs
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* and get them be in a known state. This should do what is needed
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* to get the other CPUs to call kgdb_wait(). Note that on some arches,
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* the NMI approach is not used for rounding up all the CPUs. For example,
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* in case of MIPS, smp_call_function() is used to roundup CPUs. In
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* this case, we have to make sure that interrupts are enabled before
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* calling smp_call_function(). The argument to this function is
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* the flags that will be used when restoring the interrupts. There is
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* local_irq_save() call before kgdb_roundup_cpus().
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*
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* On non-SMP systems, this is not called.
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*/
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void kgdb_roundup_cpus(unsigned long flags)
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{
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apic->send_IPI_allbutself(APIC_DM_NMI);
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}
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#endif
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/**
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* kgdb_arch_handle_exception - Handle architecture specific GDB packets.
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* @e_vector: The error vector of the exception that happened.
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* @signo: The signal number of the exception that happened.
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* @err_code: The error code of the exception that happened.
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* @remcomInBuffer: The buffer of the packet we have read.
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* @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into.
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* @linux_regs: The &struct pt_regs of the current process.
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*
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* This function MUST handle the 'c' and 's' command packets,
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* as well packets to set / remove a hardware breakpoint, if used.
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* If there are additional packets which the hardware needs to handle,
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* they are handled here. The code should return -1 if it wants to
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* process more packets, and a %0 or %1 if it wants to exit from the
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* kgdb callback.
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*/
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int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
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char *remcomInBuffer, char *remcomOutBuffer,
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struct pt_regs *linux_regs)
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{
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unsigned long addr;
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char *ptr;
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switch (remcomInBuffer[0]) {
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case 'c':
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case 's':
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/* try to read optional parameter, pc unchanged if no parm */
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ptr = &remcomInBuffer[1];
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if (kgdb_hex2long(&ptr, &addr))
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linux_regs->ip = addr;
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case 'D':
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case 'k':
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/* clear the trace bit */
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linux_regs->flags &= ~X86_EFLAGS_TF;
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atomic_set(&kgdb_cpu_doing_single_step, -1);
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/* set the trace bit if we're stepping */
|
|
if (remcomInBuffer[0] == 's') {
|
|
linux_regs->flags |= X86_EFLAGS_TF;
|
|
atomic_set(&kgdb_cpu_doing_single_step,
|
|
raw_smp_processor_id());
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* this means that we do not want to exit from the handler: */
|
|
return -1;
|
|
}
|
|
|
|
static inline int
|
|
single_step_cont(struct pt_regs *regs, struct die_args *args)
|
|
{
|
|
/*
|
|
* Single step exception from kernel space to user space so
|
|
* eat the exception and continue the process:
|
|
*/
|
|
printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
|
|
"resuming...\n");
|
|
kgdb_arch_handle_exception(args->trapnr, args->signr,
|
|
args->err, "c", "", regs);
|
|
/*
|
|
* Reset the BS bit in dr6 (pointed by args->err) to
|
|
* denote completion of processing
|
|
*/
|
|
(*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
|
|
|
|
return NOTIFY_STOP;
|
|
}
|
|
|
|
static DECLARE_BITMAP(was_in_debug_nmi, NR_CPUS);
|
|
|
|
static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
|
|
{
|
|
int cpu;
|
|
|
|
switch (cmd) {
|
|
case NMI_LOCAL:
|
|
if (atomic_read(&kgdb_active) != -1) {
|
|
/* KGDB CPU roundup */
|
|
cpu = raw_smp_processor_id();
|
|
kgdb_nmicallback(cpu, regs);
|
|
set_bit(cpu, was_in_debug_nmi);
|
|
touch_nmi_watchdog();
|
|
|
|
return NMI_HANDLED;
|
|
}
|
|
break;
|
|
|
|
case NMI_UNKNOWN:
|
|
cpu = raw_smp_processor_id();
|
|
|
|
if (__test_and_clear_bit(cpu, was_in_debug_nmi))
|
|
return NMI_HANDLED;
|
|
|
|
break;
|
|
default:
|
|
/* do nothing */
|
|
break;
|
|
}
|
|
return NMI_DONE;
|
|
}
|
|
|
|
static int __kgdb_notify(struct die_args *args, unsigned long cmd)
|
|
{
|
|
struct pt_regs *regs = args->regs;
|
|
|
|
switch (cmd) {
|
|
case DIE_DEBUG:
|
|
if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
|
|
if (user_mode(regs))
|
|
return single_step_cont(regs, args);
|
|
break;
|
|
} else if (test_thread_flag(TIF_SINGLESTEP))
|
|
/* This means a user thread is single stepping
|
|
* a system call which should be ignored
|
|
*/
|
|
return NOTIFY_DONE;
|
|
/* fall through */
|
|
default:
|
|
if (user_mode(regs))
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
|
|
return NOTIFY_DONE;
|
|
|
|
/* Must touch watchdog before return to normal operation */
|
|
touch_nmi_watchdog();
|
|
return NOTIFY_STOP;
|
|
}
|
|
|
|
int kgdb_ll_trap(int cmd, const char *str,
|
|
struct pt_regs *regs, long err, int trap, int sig)
|
|
{
|
|
struct die_args args = {
|
|
.regs = regs,
|
|
.str = str,
|
|
.err = err,
|
|
.trapnr = trap,
|
|
.signr = sig,
|
|
|
|
};
|
|
|
|
if (!kgdb_io_module_registered)
|
|
return NOTIFY_DONE;
|
|
|
|
return __kgdb_notify(&args, cmd);
|
|
}
|
|
|
|
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,
|
|
};
|
|
|
|
/**
|
|
* 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 retval;
|
|
|
|
retval = register_die_notifier(&kgdb_notifier);
|
|
if (retval)
|
|
goto out;
|
|
|
|
retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler,
|
|
0, "kgdb");
|
|
if (retval)
|
|
goto out1;
|
|
|
|
retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler,
|
|
0, "kgdb");
|
|
|
|
if (retval)
|
|
goto out2;
|
|
|
|
return retval;
|
|
|
|
out2:
|
|
unregister_nmi_handler(NMI_LOCAL, "kgdb");
|
|
out1:
|
|
unregister_die_notifier(&kgdb_notifier);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
static void kgdb_hw_overflow_handler(struct perf_event *event,
|
|
struct perf_sample_data *data, struct pt_regs *regs)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
int i;
|
|
|
|
for (i = 0; i < 4; i++)
|
|
if (breakinfo[i].enabled)
|
|
tsk->thread.debugreg6 |= (DR_TRAP0 << i);
|
|
}
|
|
|
|
void kgdb_arch_late(void)
|
|
{
|
|
int i, cpu;
|
|
struct perf_event_attr attr;
|
|
struct perf_event **pevent;
|
|
|
|
/*
|
|
* Pre-allocate the hw breakpoint structions in the non-atomic
|
|
* portion of kgdb because this operation requires mutexs to
|
|
* complete.
|
|
*/
|
|
hw_breakpoint_init(&attr);
|
|
attr.bp_addr = (unsigned long)kgdb_arch_init;
|
|
attr.bp_len = HW_BREAKPOINT_LEN_1;
|
|
attr.bp_type = HW_BREAKPOINT_W;
|
|
attr.disabled = 1;
|
|
for (i = 0; i < HBP_NUM; i++) {
|
|
if (breakinfo[i].pev)
|
|
continue;
|
|
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
|
|
if (IS_ERR((void * __force)breakinfo[i].pev)) {
|
|
printk(KERN_ERR "kgdb: Could not allocate hw"
|
|
"breakpoints\nDisabling the kernel debugger\n");
|
|
breakinfo[i].pev = NULL;
|
|
kgdb_arch_exit();
|
|
return;
|
|
}
|
|
for_each_online_cpu(cpu) {
|
|
pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
|
|
pevent[0]->hw.sample_period = 1;
|
|
pevent[0]->overflow_handler = kgdb_hw_overflow_handler;
|
|
if (pevent[0]->destroy != NULL) {
|
|
pevent[0]->destroy = NULL;
|
|
release_bp_slot(*pevent);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
int i;
|
|
for (i = 0; i < 4; i++) {
|
|
if (breakinfo[i].pev) {
|
|
unregister_wide_hw_breakpoint(breakinfo[i].pev);
|
|
breakinfo[i].pev = NULL;
|
|
}
|
|
}
|
|
unregister_nmi_handler(NMI_UNKNOWN, "kgdb");
|
|
unregister_nmi_handler(NMI_LOCAL, "kgdb");
|
|
unregister_die_notifier(&kgdb_notifier);
|
|
}
|
|
|
|
/**
|
|
*
|
|
* kgdb_skipexception - Bail out of KGDB when we've been triggered.
|
|
* @exception: Exception vector number
|
|
* @regs: Current &struct pt_regs.
|
|
*
|
|
* On some architectures we need to skip a breakpoint exception when
|
|
* it occurs after a breakpoint has been removed.
|
|
*
|
|
* Skip an int3 exception when it occurs after a breakpoint has been
|
|
* removed. Backtrack eip by 1 since the int3 would have caused it to
|
|
* increment by 1.
|
|
*/
|
|
int kgdb_skipexception(int exception, struct pt_regs *regs)
|
|
{
|
|
if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
|
|
regs->ip -= 1;
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
|
|
{
|
|
if (exception == 3)
|
|
return instruction_pointer(regs) - 1;
|
|
return instruction_pointer(regs);
|
|
}
|
|
|
|
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
|
|
{
|
|
regs->ip = ip;
|
|
}
|
|
|
|
int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
|
|
{
|
|
int err;
|
|
char opc[BREAK_INSTR_SIZE];
|
|
|
|
bpt->type = BP_BREAKPOINT;
|
|
err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
|
|
BREAK_INSTR_SIZE);
|
|
if (err)
|
|
return err;
|
|
err = probe_kernel_write((char *)bpt->bpt_addr,
|
|
arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
|
|
if (!err)
|
|
return err;
|
|
/*
|
|
* It is safe to call text_poke() because normal kernel execution
|
|
* is stopped on all cores, so long as the text_mutex is not locked.
|
|
*/
|
|
if (mutex_is_locked(&text_mutex))
|
|
return -EBUSY;
|
|
text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
|
|
BREAK_INSTR_SIZE);
|
|
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
|
|
if (err)
|
|
return err;
|
|
if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
|
|
return -EINVAL;
|
|
bpt->type = BP_POKE_BREAKPOINT;
|
|
|
|
return err;
|
|
}
|
|
|
|
int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
|
|
{
|
|
int err;
|
|
char opc[BREAK_INSTR_SIZE];
|
|
|
|
if (bpt->type != BP_POKE_BREAKPOINT)
|
|
goto knl_write;
|
|
/*
|
|
* It is safe to call text_poke() because normal kernel execution
|
|
* is stopped on all cores, so long as the text_mutex is not locked.
|
|
*/
|
|
if (mutex_is_locked(&text_mutex))
|
|
goto knl_write;
|
|
text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
|
|
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
|
|
if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
|
|
goto knl_write;
|
|
return err;
|
|
|
|
knl_write:
|
|
return probe_kernel_write((char *)bpt->bpt_addr,
|
|
(char *)bpt->saved_instr, BREAK_INSTR_SIZE);
|
|
}
|
|
|
|
struct kgdb_arch arch_kgdb_ops = {
|
|
/* Breakpoint instruction: */
|
|
.gdb_bpt_instr = { 0xcc },
|
|
.flags = KGDB_HW_BREAKPOINT,
|
|
.set_hw_breakpoint = kgdb_set_hw_break,
|
|
.remove_hw_breakpoint = kgdb_remove_hw_break,
|
|
.disable_hw_break = kgdb_disable_hw_debug,
|
|
.remove_all_hw_break = kgdb_remove_all_hw_break,
|
|
.correct_hw_break = kgdb_correct_hw_break,
|
|
};
|