x86: kgdb support
simplified and streamlined kgdb support on x86, both 32-bit and 64-bit, based on patch from: Subject: kgdb: core-lite From: Jason Wessel <jason.wessel@windriver.com> [ and countless other authors - see the patch for details. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Ingo Molnar
parent
f2d937f3bf
commit
82da3ff89d
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@ -23,6 +23,7 @@ config X86
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select HAVE_KPROBES
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select HAVE_KRETPROBES
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select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
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select HAVE_ARCH_KGDB
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config GENERIC_LOCKBREAK
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@ -66,6 +66,7 @@ obj-$(CONFIG_MODULES) += module_$(BITS).o
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obj-$(CONFIG_ACPI_SRAT) += srat_32.o
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obj-$(CONFIG_EFI) += efi.o efi_$(BITS).o efi_stub_$(BITS).o
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obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o
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obj-$(CONFIG_KGDB) += kgdb.o
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obj-$(CONFIG_VM86) += vm86_32.o
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obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
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@ -0,0 +1,417 @@
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/*
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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 <asm/apicdef.h>
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#include <asm/system.h>
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#ifdef CONFIG_X86_32
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# include <mach_ipi.h>
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#else
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# include <asm/mach_apic.h>
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#endif
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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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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_PS] = regs->flags;
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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_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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#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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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_regs[GDB_PS] = *(unsigned long *)(p->thread.sp + 8);
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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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/**
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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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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->flags = gdb_regs[GDB_PS];
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regs->ip = gdb_regs[GDB_PC];
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#ifdef CONFIG_X86_32
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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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#endif
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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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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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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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newPC = linux_regs->ip;
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/* clear the trace bit */
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linux_regs->flags &= ~TF_MASK;
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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 |= TF_MASK;
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kgdb_single_step = 1;
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if (kgdb_contthread) {
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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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}
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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 __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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return NOTIFY_STOP;
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}
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return NOTIFY_DONE;
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case DIE_NMI_IPI:
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if (atomic_read(&kgdb_active) != -1) {
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/* KGDB CPU roundup: */
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if (kgdb_nmicallback(raw_smp_processor_id(), regs))
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return NOTIFY_DONE;
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return NOTIFY_STOP;
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}
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return NOTIFY_DONE;
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case DIE_NMIWATCHDOG:
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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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return NOTIFY_STOP;
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}
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/* Enter debugger: */
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break;
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case DIE_DEBUG:
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if (atomic_read(&kgdb_cpu_doing_single_step) ==
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raw_smp_processor_id() &&
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user_mode(regs))
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return single_step_cont(regs, args);
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/* fall through */
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default:
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if (user_mode(regs))
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return NOTIFY_DONE;
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}
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if (kgdb_handle_exception(args->trapnr, args->signr, args->err, 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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* Lowest-prio notifier priority, we want to be notified last:
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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 initalization.
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*
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* This function will handle the initalization 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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return register_die_notifier(&kgdb_notifier);
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}
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/**
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* kgdb_arch_exit - Perform any architecture specific uninitalization.
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*
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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_die_notifier(&kgdb_notifier);
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}
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/**
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*
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* kgdb_skipexception - Bail out of KGDB when we've been triggered.
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* @exception: Exception vector number
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* @regs: Current &struct pt_regs.
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*
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* On some architectures we need to skip a breakpoint exception when
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* it occurs after a breakpoint has been removed.
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*
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* Skip an int3 exception when it occurs after a breakpoint has been
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* removed. Backtrack eip by 1 since the int3 would have caused it to
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* increment by 1.
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*/
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int kgdb_skipexception(int exception, struct pt_regs *regs)
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{
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if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
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regs->ip -= 1;
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return 1;
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}
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return 0;
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}
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unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
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{
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if (exception == 3)
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return instruction_pointer(regs) - 1;
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return instruction_pointer(regs);
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}
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struct kgdb_arch arch_kgdb_ops = {
|
||||
/* Breakpoint instruction: */
|
||||
.gdb_bpt_instr = { 0xcc },
|
||||
};
|
||||
|
|
@ -0,0 +1,81 @@
|
|||
#ifndef _ASM_KGDB_H_
|
||||
#define _ASM_KGDB_H_
|
||||
|
||||
/*
|
||||
* Copyright (C) 2001-2004 Amit S. Kale
|
||||
* Copyright (C) 2008 Wind River Systems, Inc.
|
||||
*/
|
||||
|
||||
/*
|
||||
* BUFMAX defines the maximum number of characters in inbound/outbound
|
||||
* buffers at least NUMREGBYTES*2 are needed for register packets
|
||||
* Longer buffer is needed to list all threads
|
||||
*/
|
||||
#define BUFMAX 1024
|
||||
|
||||
/*
|
||||
* Note that this register image is in a different order than
|
||||
* the register image that Linux produces at interrupt time.
|
||||
*
|
||||
* Linux's register image is defined by struct pt_regs in ptrace.h.
|
||||
* Just why GDB uses a different order is a historical mystery.
|
||||
*/
|
||||
#ifdef CONFIG_X86_32
|
||||
enum regnames {
|
||||
GDB_AX, /* 0 */
|
||||
GDB_CX, /* 1 */
|
||||
GDB_DX, /* 2 */
|
||||
GDB_BX, /* 3 */
|
||||
GDB_SP, /* 4 */
|
||||
GDB_BP, /* 5 */
|
||||
GDB_SI, /* 6 */
|
||||
GDB_DI, /* 7 */
|
||||
GDB_PC, /* 8 also known as eip */
|
||||
GDB_PS, /* 9 also known as eflags */
|
||||
GDB_CS, /* 10 */
|
||||
GDB_SS, /* 11 */
|
||||
GDB_DS, /* 12 */
|
||||
GDB_ES, /* 13 */
|
||||
GDB_FS, /* 14 */
|
||||
GDB_GS, /* 15 */
|
||||
};
|
||||
#else /* ! CONFIG_X86_32 */
|
||||
enum regnames {
|
||||
GDB_AX, /* 0 */
|
||||
GDB_DX, /* 1 */
|
||||
GDB_CX, /* 2 */
|
||||
GDB_BX, /* 3 */
|
||||
GDB_SI, /* 4 */
|
||||
GDB_DI, /* 5 */
|
||||
GDB_BP, /* 6 */
|
||||
GDB_SP, /* 7 */
|
||||
GDB_R8, /* 8 */
|
||||
GDB_R9, /* 9 */
|
||||
GDB_R10, /* 10 */
|
||||
GDB_R11, /* 11 */
|
||||
GDB_R12, /* 12 */
|
||||
GDB_R13, /* 13 */
|
||||
GDB_R14, /* 14 */
|
||||
GDB_R15, /* 15 */
|
||||
GDB_PC, /* 16 */
|
||||
GDB_PS, /* 17 */
|
||||
};
|
||||
#endif /* CONFIG_X86_32 */
|
||||
|
||||
/*
|
||||
* Number of bytes of registers:
|
||||
*/
|
||||
#ifdef CONFIG_X86_32
|
||||
# define NUMREGBYTES 64
|
||||
#else
|
||||
# define NUMREGBYTES ((GDB_PS+1)*8)
|
||||
#endif
|
||||
|
||||
static inline void arch_kgdb_breakpoint(void)
|
||||
{
|
||||
asm(" int $3");
|
||||
}
|
||||
#define BREAK_INSTR_SIZE 1
|
||||
#define CACHE_FLUSH_IS_SAFE 1
|
||||
|
||||
#endif /* _ASM_KGDB_H_ */
|
||||
Loading…
Reference in New Issue