584 lines
15 KiB
C
584 lines
15 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/init.h>
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#include <linux/smp.h>
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#include <linux/nmi.h>
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#include <asm/apicdef.h>
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#include <asm/system.h>
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#include <asm/apic.h>
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/*
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* Put the error code here just in case the user cares:
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*/
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static int gdb_x86errcode;
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/*
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* Likewise, the vector number here (since GDB only gets the signal
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* number through the usual means, and that's not very specific):
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*/
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static int gdb_x86vector = -1;
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/**
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* pt_regs_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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* @regs: The &struct pt_regs of the current process.
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*
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* Convert the pt_regs in @regs into the format for registers that
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* GDB expects, stored in @gdb_regs.
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*/
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void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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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] = regs->ax;
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gdb_regs[GDB_BX] = regs->bx;
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gdb_regs[GDB_CX] = regs->cx;
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gdb_regs[GDB_DX] = regs->dx;
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gdb_regs[GDB_SI] = regs->si;
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gdb_regs[GDB_DI] = regs->di;
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gdb_regs[GDB_BP] = regs->bp;
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gdb_regs[GDB_PC] = regs->ip;
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#ifdef CONFIG_X86_32
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gdb_regs[GDB_PS] = regs->flags;
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gdb_regs[GDB_DS] = regs->ds;
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gdb_regs[GDB_ES] = regs->es;
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gdb_regs[GDB_CS] = regs->cs;
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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_regs[GDB_R8] = regs->r8;
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gdb_regs[GDB_R9] = regs->r9;
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gdb_regs[GDB_R10] = regs->r10;
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gdb_regs[GDB_R11] = regs->r11;
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gdb_regs[GDB_R12] = regs->r12;
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gdb_regs[GDB_R13] = regs->r13;
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gdb_regs[GDB_R14] = regs->r14;
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gdb_regs[GDB_R15] = regs->r15;
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gdb_regs32[GDB_PS] = regs->flags;
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gdb_regs32[GDB_CS] = regs->cs;
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gdb_regs32[GDB_SS] = regs->ss;
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#endif
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gdb_regs[GDB_SP] = regs->sp;
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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] = p->thread.ip;
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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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/**
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* gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
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* @gdb_regs: A pointer to hold the registers we've received from GDB.
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* @regs: A pointer to a &struct pt_regs to hold these values in.
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*
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* Convert the GDB regs in @gdb_regs into the pt_regs, and store them
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* in @regs.
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*/
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void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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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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regs->ax = gdb_regs[GDB_AX];
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regs->bx = gdb_regs[GDB_BX];
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regs->cx = gdb_regs[GDB_CX];
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regs->dx = gdb_regs[GDB_DX];
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regs->si = gdb_regs[GDB_SI];
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regs->di = gdb_regs[GDB_DI];
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regs->bp = gdb_regs[GDB_BP];
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regs->ip = gdb_regs[GDB_PC];
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#ifdef CONFIG_X86_32
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regs->flags = gdb_regs[GDB_PS];
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regs->ds = gdb_regs[GDB_DS];
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regs->es = gdb_regs[GDB_ES];
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regs->cs = gdb_regs[GDB_CS];
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#else
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regs->r8 = gdb_regs[GDB_R8];
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regs->r9 = gdb_regs[GDB_R9];
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regs->r10 = gdb_regs[GDB_R10];
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regs->r11 = gdb_regs[GDB_R11];
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regs->r12 = gdb_regs[GDB_R12];
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regs->r13 = gdb_regs[GDB_R13];
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regs->r14 = gdb_regs[GDB_R14];
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regs->r15 = gdb_regs[GDB_R15];
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regs->flags = gdb_regs32[GDB_PS];
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regs->cs = gdb_regs32[GDB_CS];
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regs->ss = gdb_regs32[GDB_SS];
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#endif
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}
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static struct hw_breakpoint {
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unsigned enabled;
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unsigned type;
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unsigned len;
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unsigned long addr;
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} breakinfo[4];
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static void kgdb_correct_hw_break(void)
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{
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unsigned long dr7;
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int correctit = 0;
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int breakbit;
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int breakno;
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get_debugreg(dr7, 7);
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for (breakno = 0; breakno < 4; breakno++) {
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breakbit = 2 << (breakno << 1);
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if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
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correctit = 1;
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dr7 |= breakbit;
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dr7 &= ~(0xf0000 << (breakno << 2));
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dr7 |= ((breakinfo[breakno].len << 2) |
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breakinfo[breakno].type) <<
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((breakno << 2) + 16);
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if (breakno >= 0 && breakno <= 3)
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set_debugreg(breakinfo[breakno].addr, breakno);
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} else {
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if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
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correctit = 1;
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dr7 &= ~breakbit;
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dr7 &= ~(0xf0000 << (breakno << 2));
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}
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}
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}
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if (correctit)
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set_debugreg(dr7, 7);
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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 < 4; i++)
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if (breakinfo[i].addr == addr && breakinfo[i].enabled)
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break;
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if (i == 4)
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return -1;
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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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for (i = 0; i < 4; i++)
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memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
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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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unsigned type;
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int i;
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for (i = 0; i < 4; i++)
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if (!breakinfo[i].enabled)
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break;
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if (i == 4)
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return -1;
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switch (bptype) {
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case BP_HARDWARE_BREAKPOINT:
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type = 0;
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len = 1;
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break;
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case BP_WRITE_WATCHPOINT:
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type = 1;
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break;
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case BP_ACCESS_WATCHPOINT:
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type = 3;
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break;
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default:
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return -1;
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}
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if (len == 1 || len == 2 || len == 4)
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breakinfo[i].len = len - 1;
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else
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return -1;
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breakinfo[i].enabled = 1;
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breakinfo[i].addr = addr;
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breakinfo[i].type = type;
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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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void kgdb_disable_hw_debug(struct pt_regs *regs)
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{
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/* Disable hardware debugging while we are in kgdb: */
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set_debugreg(0UL, 7);
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}
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/**
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* kgdb_post_primary_code - Save error vector/code numbers.
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* @regs: Original pt_regs.
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* @e_vector: Original error vector.
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* @err_code: Original error code.
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*
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* This is needed on architectures which support SMP and KGDB.
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* This function is called after all the slave cpus have been put
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* to a know spin state and the primary CPU has control over KGDB.
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*/
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void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
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{
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/* primary processor is completely in the debugger */
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gdb_x86vector = e_vector;
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gdb_x86errcode = err_code;
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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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* @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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* @remcom_in_buffer: The buffer of the packet we have read.
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* @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
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* @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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unsigned long dr6;
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char *ptr;
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int newPC;
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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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newPC = linux_regs->ip;
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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 */
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if (remcomInBuffer[0] == 's') {
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linux_regs->flags |= X86_EFLAGS_TF;
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kgdb_single_step = 1;
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atomic_set(&kgdb_cpu_doing_single_step,
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raw_smp_processor_id());
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}
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get_debugreg(dr6, 6);
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if (!(dr6 & 0x4000)) {
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int breakno;
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for (breakno = 0; breakno < 4; breakno++) {
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if (dr6 & (1 << breakno) &&
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breakinfo[breakno].type == 0) {
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/* Set restore flag: */
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linux_regs->flags |= X86_EFLAGS_RF;
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break;
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}
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}
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}
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set_debugreg(0UL, 6);
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kgdb_correct_hw_break();
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return 0;
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}
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/* this means that we do not want to exit from the handler: */
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return -1;
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}
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static inline int
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single_step_cont(struct pt_regs *regs, struct die_args *args)
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{
|
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/*
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* Single step exception from kernel space to user space so
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* eat the exception and continue the process:
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*/
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printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
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"resuming...\n");
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kgdb_arch_handle_exception(args->trapnr, args->signr,
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args->err, "c", "", regs);
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return NOTIFY_STOP;
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}
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static int was_in_debug_nmi[NR_CPUS];
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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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switch (cmd) {
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case DIE_NMI:
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if (atomic_read(&kgdb_active) != -1) {
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/* KGDB CPU roundup */
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kgdb_nmicallback(raw_smp_processor_id(), regs);
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was_in_debug_nmi[raw_smp_processor_id()] = 1;
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touch_nmi_watchdog();
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return NOTIFY_STOP;
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}
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return NOTIFY_DONE;
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|
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case DIE_NMI_IPI:
|
|
/* Just ignore, we will handle the roundup on DIE_NMI. */
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return NOTIFY_DONE;
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|
|
case DIE_NMIUNKNOWN:
|
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if (was_in_debug_nmi[raw_smp_processor_id()]) {
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was_in_debug_nmi[raw_smp_processor_id()] = 0;
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return NOTIFY_STOP;
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|
}
|
|
return NOTIFY_DONE;
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|
|
case DIE_NMIWATCHDOG:
|
|
if (atomic_read(&kgdb_active) != -1) {
|
|
/* KGDB CPU roundup: */
|
|
kgdb_nmicallback(raw_smp_processor_id(), regs);
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return NOTIFY_STOP;
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}
|
|
/* Enter debugger: */
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break;
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|
|
case DIE_DEBUG:
|
|
if (atomic_read(&kgdb_cpu_doing_single_step) ==
|
|
raw_smp_processor_id()) {
|
|
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, args->err, regs))
|
|
return NOTIFY_DONE;
|
|
|
|
/* Must touch watchdog before return to normal operation */
|
|
touch_nmi_watchdog();
|
|
return NOTIFY_STOP;
|
|
}
|
|
|
|
static int
|
|
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
|
|
{
|
|
unsigned long flags;
|
|
int ret;
|
|
|
|
local_irq_save(flags);
|
|
ret = __kgdb_notify(ptr, cmd);
|
|
local_irq_restore(flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct notifier_block kgdb_notifier = {
|
|
.notifier_call = kgdb_notify,
|
|
|
|
/*
|
|
* Lowest-prio notifier priority, we want to be notified last:
|
|
*/
|
|
.priority = -INT_MAX,
|
|
};
|
|
|
|
/**
|
|
* kgdb_arch_init - Perform any architecture specific initalization.
|
|
*
|
|
* This function will handle the initalization of any architecture
|
|
* specific callbacks.
|
|
*/
|
|
int kgdb_arch_init(void)
|
|
{
|
|
return register_die_notifier(&kgdb_notifier);
|
|
}
|
|
|
|
/**
|
|
* kgdb_arch_exit - Perform any architecture specific uninitalization.
|
|
*
|
|
* This function will handle the uninitalization of any architecture
|
|
* specific callbacks, for dynamic registration and unregistration.
|
|
*/
|
|
void kgdb_arch_exit(void)
|
|
{
|
|
unregister_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);
|
|
}
|
|
|
|
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,
|
|
.remove_all_hw_break = kgdb_remove_all_hw_break,
|
|
.correct_hw_break = kgdb_correct_hw_break,
|
|
};
|