Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758091AbYBJJTA (ORCPT ); Sun, 10 Feb 2008 04:19:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752233AbYBJJSn (ORCPT ); Sun, 10 Feb 2008 04:18:43 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:46650 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751708AbYBJJS2 (ORCPT ); Sun, 10 Feb 2008 04:18:28 -0500 Date: Sun, 10 Feb 2008 10:17:57 +0100 From: Ingo Molnar To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Thomas Gleixner , Jason Wessel Subject: Re: [3/6] kgdb: core Message-ID: <20080210091757.GA17341@elte.hu> References: <20080210071331.GC3851@elte.hu> <20080210073542.GB26666@infradead.org> <20080210074352.GA7188@elte.hu> <20080210075732.GA9349@infradead.org> <20080210080225.GC7188@elte.hu> <20080210082132.GA9878@elte.hu> <20080210082624.GB10479@infradead.org> <20080210090817.GA15409@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080210090817.GA15409@elte.hu> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 106735 Lines: 3966 * Ingo Molnar wrote: > Anyway, to resolve this i've turning them into non-docbook, > descriptive comments. Please submit any docbook patch to > arch/x86/kernel/kgdb.c to x86.git if you'd like more documentation. no need for that btw, i just added the docbook entries to arch/x86/kernel/kgdb.c myself and fixed all of kgdb.h. Tree is at: git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb.git tip 2e3ebf25b0bd8646e517806073e1991be1fec8a2. Shortlog, diffstat and the full patch can be found below, with all relevant review feedback addressed. Builds, boots and works fine on x86. Ingo ------------------> Ingo Molnar (3): pids: add pid_max prototype uaccess: add probe_kernel_write() x86: kgdb support Jan Kiszka (1): consoles: polling support, kgdboc Jason Wessel (2): kgdb: core kgdb: document parameters Documentation/kernel-parameters.txt | 5 + arch/x86/Kconfig | 4 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/kgdb.c | 672 ++++++++++++ drivers/char/tty_io.c | 47 + drivers/serial/8250.c | 62 ++ drivers/serial/Kconfig | 3 + drivers/serial/Makefile | 1 + drivers/serial/kgdboc.c | 164 +++ drivers/serial/serial_core.c | 67 ++- include/asm-generic/kgdb.h | 91 ++ include/asm-x86/kgdb.h | 85 ++ include/linux/kgdb.h | 333 ++++++ include/linux/pid.h | 2 + include/linux/serial_core.h | 4 + include/linux/tty_driver.h | 12 + include/linux/uaccess.h | 22 + kernel/Makefile | 1 + kernel/kgdb.c | 2019 +++++++++++++++++++++++++++++++++++ kernel/sysctl.c | 2 +- lib/Kconfig.debug | 2 + lib/Kconfig.kgdb | 37 + 22 files changed, 3634 insertions(+), 2 deletions(-) create mode 100644 arch/x86/kernel/kgdb.c create mode 100644 drivers/serial/kgdboc.c create mode 100644 include/asm-generic/kgdb.h create mode 100644 include/asm-x86/kgdb.h create mode 100644 include/linux/kgdb.h create mode 100644 kernel/kgdb.c create mode 100644 lib/Kconfig.kgdb diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a4fc7fc..6e97307 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -930,6 +930,11 @@ and is between 256 and 4096 characters. It is defined in the file kstack=N [X86-32,X86-64] Print N words from the kernel stack in oops dumps. + kgdboc= [HW] kgdb over consoles. + Requires a tty driver that supports console polling. + (only serial suported for now) + Format: [,baud] + l2cr= [PPC] lapic [X86-32,APIC] Enable the local APIC even if BIOS diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index aaed1a3..85bcc23 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -14,6 +14,7 @@ config X86_32 config X86_64 def_bool 64BIT + select HAVE_ARCH_KGDB_SHADOW_INFO ### Arch settings config X86 @@ -143,6 +144,9 @@ config AUDIT_ARCH config ARCH_SUPPORTS_AOUT def_bool y +config HAVE_ARCH_KGDB + def_bool y + # Use the generic interrupt handling code in kernel/irq/: config GENERIC_HARDIRQS bool diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 76ec0f8..4cd39cd 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -58,6 +58,7 @@ obj-$(CONFIG_MODULES) += module_$(BITS).o obj-$(CONFIG_ACPI_SRAT) += srat_32.o obj-$(CONFIG_EFI) += efi.o efi_$(BITS).o efi_stub_$(BITS).o obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o +obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_VM86) += vm86_32.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c new file mode 100644 index 0000000..7130273 --- /dev/null +++ b/arch/x86/kernel/kgdb.c @@ -0,0 +1,672 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + */ + +/* + * Copyright (C) 2004 Amit S. Kale + * Copyright (C) 2000-2001 VERITAS Software Corporation. + * Copyright (C) 2002 Andi Kleen, SuSE Labs + * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd. + * Copyright (C) 2007 MontaVista Software, Inc. + * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc. + */ +/**************************************************************************** + * Contributor: Lake Stevens Instrument Division$ + * Written by: Glenn Engel $ + * Updated by: Amit Kale + * Updated by: Tom Rini + * Updated by: Jason Wessel + * Modified for 386 by Jim Kingdon, Cygnus Support. + * Origianl kgdb, compatibility with 2.1.xx kernel by + * David Grothe + * Integrated into 2.2.5 kernel by Tigran Aivazian + * X86_64 changes from Andi Kleen's patch merged by Jim Houston + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#ifdef CONFIG_X86_32 +# include +#else +# include +#endif + +/* + * Put the error code here just in case the user cares: + */ +static int gdb_x86errcode; + +/* + * Likewise, the vector number here (since GDB only gets the signal + * number through the usual means, and that's not very specific): + */ +static int gdb_x86vector = -1; + +/** + * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @regs: The &struct pt_regs of the current process. + * + * Convert the pt_regs in @regs into the format for registers that + * GDB expects, stored in @gdb_regs. + */ +void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + gdb_regs[GDB_AX] = regs->ax; + gdb_regs[GDB_BX] = regs->bx; + gdb_regs[GDB_CX] = regs->cx; + gdb_regs[GDB_DX] = regs->dx; + gdb_regs[GDB_SI] = regs->si; + gdb_regs[GDB_DI] = regs->di; + gdb_regs[GDB_BP] = regs->bp; + gdb_regs[GDB_PS] = regs->flags; + gdb_regs[GDB_PC] = regs->ip; +#ifdef CONFIG_X86_32 + gdb_regs[GDB_DS] = regs->ds; + gdb_regs[GDB_ES] = regs->es; + gdb_regs[GDB_CS] = regs->cs; + gdb_regs[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_FS] = 0xFFFF; + gdb_regs[GDB_GS] = 0xFFFF; +#else + gdb_regs[GDB_R8] = regs->r8; + gdb_regs[GDB_R9] = regs->r9; + gdb_regs[GDB_R10] = regs->r10; + gdb_regs[GDB_R11] = regs->r11; + gdb_regs[GDB_R12] = regs->r12; + gdb_regs[GDB_R13] = regs->r13; + gdb_regs[GDB_R14] = regs->r14; + gdb_regs[GDB_R15] = regs->r15; +#endif + gdb_regs[GDB_SP] = regs->sp; +} + +/** + * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @p: The &struct task_struct of the desired process. + * + * Convert the register values of the sleeping process in @p to + * the format that GDB expects. + * This function is called when kgdb does not have access to the + * &struct pt_regs and therefore it should fill the gdb registers + * @gdb_regs with what has been saved in &struct thread_struct + * thread field during switch_to. + */ +void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) +{ + gdb_regs[GDB_AX] = 0; + gdb_regs[GDB_BX] = 0; + gdb_regs[GDB_CX] = 0; + gdb_regs[GDB_DX] = 0; + gdb_regs[GDB_SI] = 0; + gdb_regs[GDB_DI] = 0; + gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; +#ifdef CONFIG_X86_32 + gdb_regs[GDB_DS] = __KERNEL_DS; + gdb_regs[GDB_ES] = __KERNEL_DS; + gdb_regs[GDB_PS] = 0; + gdb_regs[GDB_CS] = __KERNEL_CS; + gdb_regs[GDB_PC] = p->thread.ip; + gdb_regs[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_FS] = 0xFFFF; + gdb_regs[GDB_GS] = 0xFFFF; +#else + gdb_regs[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); + gdb_regs[GDB_PC] = 0; + gdb_regs[GDB_R8] = 0; + gdb_regs[GDB_R9] = 0; + gdb_regs[GDB_R10] = 0; + gdb_regs[GDB_R11] = 0; + gdb_regs[GDB_R12] = 0; + gdb_regs[GDB_R13] = 0; + gdb_regs[GDB_R14] = 0; + gdb_regs[GDB_R15] = 0; +#endif + gdb_regs[GDB_SP] = p->thread.sp; +} + +/** + * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. + * @gdb_regs: A pointer to hold the registers we've received from GDB. + * @regs: A pointer to a &struct pt_regs to hold these values in. + * + * Convert the GDB regs in @gdb_regs into the pt_regs, and store them + * in @regs. + */ +void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + regs->ax = gdb_regs[GDB_AX]; + regs->bx = gdb_regs[GDB_BX]; + regs->cx = gdb_regs[GDB_CX]; + regs->dx = gdb_regs[GDB_DX]; + regs->si = gdb_regs[GDB_SI]; + regs->di = gdb_regs[GDB_DI]; + regs->bp = gdb_regs[GDB_BP]; + regs->flags = gdb_regs[GDB_PS]; + regs->ip = gdb_regs[GDB_PC]; +#ifdef CONFIG_X86_32 + regs->ds = gdb_regs[GDB_DS]; + regs->es = gdb_regs[GDB_ES]; + regs->cs = gdb_regs[GDB_CS]; +#else + regs->r8 = gdb_regs[GDB_R8]; + regs->r9 = gdb_regs[GDB_R9]; + regs->r10 = gdb_regs[GDB_R10]; + regs->r11 = gdb_regs[GDB_R11]; + regs->r12 = gdb_regs[GDB_R12]; + regs->r13 = gdb_regs[GDB_R13]; + regs->r14 = gdb_regs[GDB_R14]; + regs->r15 = gdb_regs[GDB_R15]; +#endif +} + +static struct hw_breakpoint { + unsigned enabled; + unsigned type; + unsigned len; + unsigned long addr; +} breakinfo[4] = { + { .enabled = 0 }, + { .enabled = 0 }, + { .enabled = 0 }, + { .enabled = 0 }, +}; + +static void kgdb_correct_hw_break(void) +{ + unsigned long dr7; + int correctit = 0; + int breakbit; + int breakno; + + get_debugreg(dr7, 7); + for (breakno = 0; breakno < 4; breakno++) { + breakbit = 2 << (breakno << 1); + if (!(dr7 & breakbit) && breakinfo[breakno].enabled) { + correctit = 1; + dr7 |= breakbit; + dr7 &= ~(0xf0000 << (breakno << 2)); + dr7 |= ((breakinfo[breakno].len << 2) | + breakinfo[breakno].type) << + ((breakno << 2) + 16); + switch (breakno) { + case 0: + set_debugreg(breakinfo[0].addr, 0); + break; + + case 1: + set_debugreg(breakinfo[1].addr, 1); + break; + + case 2: + set_debugreg(breakinfo[2].addr, 2); + break; + + case 3: + set_debugreg(breakinfo[3].addr, 3); + break; + } + } else if ((dr7 & breakbit) && !breakinfo[breakno].enabled) { + correctit = 1; + dr7 &= ~breakbit; + dr7 &= ~(0xf0000 << (breakno << 2)); + } + } + if (correctit) + set_debugreg(dr7, 7); +} + +static int +kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) +{ + int i; + + for (i = 0; i < 4; i++) + if (breakinfo[i].addr == addr && breakinfo[i].enabled) + break; + if (i == 4) + return -1; + + breakinfo[i].enabled = 0; + + return 0; +} + +static void kgdb_remove_all_hw_break(void) +{ + int i; + + for (i = 0; i < 4; i++) + memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint)); +} + +static int +kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) +{ + unsigned type; + int i; + + for (i = 0; i < 4; i++) + if (!breakinfo[i].enabled) + break; + if (i == 4) + return -1; + + switch (bptype) { + case BP_HARDWARE_BREAKPOINT: + type = 0; + len = 1; + break; + case BP_WRITE_WATCHPOINT: + type = 1; + break; + case BP_ACCESS_WATCHPOINT: + type = 3; + break; + default: + return -1; + } + + if (len == 1 || len == 2 || len == 4) + breakinfo[i].len = len - 1; + else + return -1; + + breakinfo[i].enabled = 1; + breakinfo[i].addr = addr; + breakinfo[i].type = type; + + return 0; +} + +/** + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +void kgdb_disable_hw_debug(struct pt_regs *regs) +{ + /* Disable hardware debugging while we are in kgdb: */ + set_debugreg(0UL, 7); +} + +/** + * kgdb_post_master_code - Save error vector/code numbers. + * @regs: Original pt_regs. + * @e_vector: Original error vector. + * @err_code: Original error code. + * + * This is needed on architectures which support SMP and KGDB. + * This function is called after all the slave cpus have been put + * to a know spin state and the master CPU has control over KGDB. + */ +void kgdb_post_master_code(struct pt_regs *regs, int e_vector, int err_code) +{ + /* Master processor is completely in the debugger */ + gdb_x86vector = e_vector; + gdb_x86errcode = err_code; +} + +#ifdef CONFIG_SMP +/** + * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * @flags: Current IRQ state + * + * On SMP systems, we need to get the attention of the other CPUs + * and get them be in a known state. This should do what is needed + * to get the other CPUs to call kgdb_wait(). Note that on some arches, + * the NMI approach is not used for rounding up all the CPUs. For example, + * in case of MIPS, smp_call_function() is used to roundup CPUs. In + * this case, we have to make sure that interrupts are enabled before + * calling smp_call_function(). The argument to this function is + * the flags that will be used when restoring the interrupts. There is + * local_irq_save() call before kgdb_roundup_cpus(). + * + * On non-SMP systems, this is not called. + */ +void kgdb_roundup_cpus(unsigned long flags) +{ + send_IPI_allbutself(APIC_DM_NMI); +} +#endif + +/** + * kgdb_arch_handle_exception - Handle architecture specific GDB packets. + * @vector: The error vector of the exception that happened. + * @signo: The signal number of the exception that happened. + * @err_code: The error code of the exception that happened. + * @remcom_in_buffer: The buffer of the packet we have read. + * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. + * @regs: The &struct pt_regs of the current process. + * + * This function MUST handle the 'c' and 's' command packets, + * as well packets to set / remove a hardware breakpoint, if used. + * If there are additional packets which the hardware needs to handle, + * they are handled here. The code should return -1 if it wants to + * process more packets, and a %0 or %1 if it wants to exit from the + * kgdb callback. + */ +int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, + char *remcomInBuffer, char *remcomOutBuffer, + struct pt_regs *linux_regs) +{ + unsigned long addr; + unsigned long dr6; + char *ptr; + int newPC; + + switch (remcomInBuffer[0]) { + case 'c': + case 's': + /* try to read optional parameter, pc unchanged if no parm */ + ptr = &remcomInBuffer[1]; + if (kgdb_hex2long(&ptr, &addr)) + linux_regs->ip = addr; + newPC = linux_regs->ip; + + /* clear the trace bit */ + linux_regs->flags &= ~TF_MASK; + atomic_set(&cpu_doing_single_step, -1); + + /* set the trace bit if we're stepping */ + if (remcomInBuffer[0] == 's') { + linux_regs->flags |= TF_MASK; + kgdb_single_step = 1; + if (kgdb_contthread) { + atomic_set(&cpu_doing_single_step, + raw_smp_processor_id()); + } + } + + get_debugreg(dr6, 6); + if (!(dr6 & 0x4000)) { + int breakno; + + for (breakno = 0; breakno < 4; breakno++) { + if (dr6 & (1 << breakno) && + breakinfo[breakno].type == 0) { + /* Set restore flag: */ + linux_regs->flags |= X86_EFLAGS_RF; + break; + } + } + } + set_debugreg(0UL, 6); + kgdb_correct_hw_break(); + + return 0; + } + + /* this means that we do not want to exit from the handler: */ + return -1; +} + +#ifdef CONFIG_X86_64 + +static struct pt_regs *in_interrupt_stack(unsigned long rsp, int cpu) +{ + struct pt_regs *regs = NULL; + unsigned long end = (unsigned long)cpu_pda(cpu)->irqstackptr; + + if (rsp <= end && rsp >= end - IRQSTACKSIZE + 8) + regs = *(((struct pt_regs **)end) - 1); + + return regs; +} + +static struct pt_regs *in_exception_stack(unsigned long rsp, int cpu) +{ + struct tss_struct *init_tss = &__get_cpu_var(init_tss); + struct pt_regs *regs; + int i; + + for (i = 0; i < N_EXCEPTION_STACKS; i++) + if (rsp >= init_tss[cpu].x86_tss.ist[i] && + rsp <= init_tss[cpu].x86_tss.ist[i] + EXCEPTION_STKSZ) { + regs = (void *) init_tss[cpu].x86_tss.ist[i] +\ + EXCEPTION_STKSZ; + return regs - 1; + } + + return NULL; +} + +/** + * kgdb_shadowinfo - Get shadowed information on @threadid. + * @regs: The &struct pt_regs of the current process. + * @buffer: A buffer of %BUFMAX size. + * @threadid: The thread id of the shadowed process to get information on. + */ +void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid) +{ + static char intr_desc[] = "Stack at interrupt entrypoint"; + static char exc_desc[] = "Stack at exception entrypoint"; + int cpu = raw_smp_processor_id(); + struct pt_regs *stregs; + + stregs = in_interrupt_stack(regs->sp, cpu); + if (stregs) { + kgdb_mem2hex(intr_desc, buffer, strlen(intr_desc)); + } else { + stregs = in_exception_stack(regs->sp, cpu); + if (stregs) + kgdb_mem2hex(exc_desc, buffer, strlen(exc_desc)); + } +} + +/** + * kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id of the shadowed process to get information on. + * + * RETURN: + * This returns a pointer to the &struct task_struct of the shadowed + * thread, @threadid. + */ +struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs, int threadid) +{ + int cpu = raw_smp_processor_id(); + struct pt_regs *stregs; + + stregs = in_interrupt_stack(regs->sp, cpu); + if (stregs) { + return current; + } else { + stregs = in_exception_stack(regs->sp, cpu); + if (stregs) + return current; + } + + return NULL; +} + +/** + * kgdb_shadow_regs - Return the shadowed registers of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id we want the &struct pt_regs for. + * + * RETURN: + * The a pointer to the &struct pt_regs of the shadowed thread @threadid. + */ +struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid) +{ + int cpu = raw_smp_processor_id(); + struct pt_regs *stregs; + + stregs = in_interrupt_stack(regs->sp, cpu); + if (stregs) { + return stregs; + } else { + stregs = in_exception_stack(regs->sp, cpu); + if (stregs) + return stregs; + } + + return NULL; +} + +#endif /* CONFIG_X86_64 */ + +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); + + return NOTIFY_STOP; +} + +static int +kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) +{ + struct die_args *args = ptr; + struct pt_regs *regs = args->regs; + + switch (cmd) { + case DIE_NMI: + if (atomic_read(&kgdb_active)) { + /* KGDB CPU roundup */ + kgdb_nmicallback(raw_smp_processor_id(), regs); + return NOTIFY_STOP; + } + return NOTIFY_DONE; + + case DIE_NMI_IPI: + if (atomic_read(&kgdb_active)) { + /* KGDB CPU roundup: */ + if (kgdb_nmicallback(raw_smp_processor_id(), regs)) + return NOTIFY_DONE; + return NOTIFY_STOP; + } + return NOTIFY_DONE; + + case DIE_NMIWATCHDOG: + if (atomic_read(&kgdb_active)) { + /* KGDB CPU roundup: */ + kgdb_nmicallback(raw_smp_processor_id(), regs); + return NOTIFY_STOP; + } + /* Enter debugger: */ + break; + + case DIE_DEBUG: + if (atomic_read(&cpu_doing_single_step) == + raw_smp_processor_id() && + user_mode(regs)) + return single_step_cont(regs, args); + /* fall through */ + default: + if (user_mode(regs)) + return NOTIFY_DONE; + } + + if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) + return NOTIFY_DONE; + + return NOTIFY_STOP; +} + +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) +{ + register_die_notifier(&kgdb_notifier); + return 0; +} + + +/** + * kgdb_arch_uninit - Perform any architecture specific uninitalization. + * + * This function will handle the uninitalization of any architecture + * specific callbacks, for dynamic registration and unregistration. + */ +void kgdb_arch_uninit(void) +{ + unregister_die_notifier(&kgdb_notifier); +} + +/** + * + * kgdb_skipexception - Bail of 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, +#ifndef CONFIG_X86_32 + .shadowth = 1, +#endif + .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, +}; diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 613ec81..4d3c701 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) return NULL; } +#ifdef CONFIG_CONSOLE_POLL + +/** + * tty_find_polling_driver - find device of a polled tty + * @name: name string to match + * @line: pointer to resulting tty line nr + * + * This routine returns a tty driver structure, given a name + * and the condition that the tty driver is capable of polled + * operation. + */ +struct tty_driver *tty_find_polling_driver(char *name, int *line) +{ + struct tty_driver *p, *res = NULL; + int tty_line = 0; + char *str; + + mutex_lock(&tty_mutex); + /* Search through the tty devices to look for a match */ + list_for_each_entry(p, &tty_drivers, tty_drivers) { + str = name + strlen(p->name); + tty_line = simple_strtoul(str, &str, 10); + if (*str == ',') + str++; + if (*str == '\0') + str = 0; + + if (tty_line >= 0 && tty_line <= p->num && p->poll_init && + !p->poll_init(p, tty_line, str)) { + + res = p; + *line = tty_line; + break; + } + } + mutex_unlock(&tty_mutex); + + return res; +} +EXPORT_SYMBOL_GPL(tty_find_polling_driver); +#endif + /** * tty_check_change - check for POSIX terminal changes * @tty: tty to check @@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver, driver->write_proc = op->write_proc; driver->tiocmget = op->tiocmget; driver->tiocmset = op->tiocmset; +#ifdef CONFIG_CONSOLE_POLL + driver->poll_init = op->poll_init; + driver->poll_get_char = op->poll_get_char; + driver->poll_put_char = op->poll_put_char; +#endif } diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 77f7a7f..be86c3e 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1740,6 +1740,64 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits) } } +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context. + */ + +static int serial8250_get_poll_char(struct uart_port *port) +{ + struct uart_8250_port *up = (struct uart_8250_port *)port; + unsigned char lsr = serial_inp(up, UART_LSR); + + while (!(lsr & UART_LSR_DR)) + lsr = serial_inp(up, UART_LSR); + + return serial_inp(up, UART_RX); +} + + +static void serial8250_put_poll_char(struct uart_port *port, + unsigned char c) +{ + unsigned int ier; + struct uart_8250_port *up = (struct uart_8250_port *)port; + + /* + * First save the IER then disable the interrupts + */ + ier = serial_in(up, UART_IER); +#ifdef UART_CAP_UUE + if (up->capabilities & UART_CAP_UUE) +#else + if (up->port.type == PORT_XSCALE) +#endif + serial_out(up, UART_IER, UART_IER_UUE); + else + serial_out(up, UART_IER, 0); + + wait_for_xmitr(up, BOTH_EMPTY); + /* + * Send the character out. + * If a LF, also do CR... + */ + serial_out(up, UART_TX, c); + if (c == 10) { + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_TX, 13); + } + + /* + * Finally, wait for transmitter to become empty + * and restore the IER + */ + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_IER, ier); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static int serial8250_startup(struct uart_port *port) { struct uart_8250_port *up = (struct uart_8250_port *)port; @@ -2386,6 +2444,10 @@ static struct uart_ops serial8250_pops = { .request_port = serial8250_request_port, .config_port = serial8250_config_port, .verify_port = serial8250_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif }; static struct uart_8250_port serial8250_ports[UART_NR]; diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index b82595c..5d9667c 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -961,6 +961,9 @@ config SERIAL_CORE config SERIAL_CORE_CONSOLE bool +config CONSOLE_POLL + bool + config SERIAL_68328 bool "68328 serial support" depends on M68328 || M68EZ328 || M68VZ328 diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index 640cfe4..1d8ee05 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o obj-$(CONFIG_SERIAL_NETX) += netx-serial.o obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o +obj-$(CONFIG_KGDBOC) += kgdboc.o obj-$(CONFIG_SERIAL_QE) += ucc_uart.o diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c new file mode 100644 index 0000000..5079d32 --- /dev/null +++ b/drivers/serial/kgdboc.c @@ -0,0 +1,164 @@ +/* + * drivers/serial/kgdboc.c + * + * Based on the same principle as kgdboe using the NETPOLL api, this + * driver uses a console polling api to implement a gdb serial inteface + * which is multiplexed on a console port. + * + * Maintainer: Jason Wessel + * + * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ +#include +#include +#include +#include + +#define MAX_KGDBOC_CONFIG_STR 40 + +static struct kgdb_io kgdboc_io_ops; + +/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ +static int configured = -1; + +MODULE_DESCRIPTION("KGDB Console TTY Driver"); +MODULE_LICENSE("GPL"); +static char config[MAX_KGDBOC_CONFIG_STR]; +static struct kparam_string kps = { + .string = config, + .maxlen = MAX_KGDBOC_CONFIG_STR, +}; + +static struct tty_driver *kgdb_tty_driver; +static int kgdb_tty_line; + +static int kgdboc_option_setup(char *opt) +{ + if (strlen(opt) > MAX_KGDBOC_CONFIG_STR) { + printk(KERN_ERR "kgdboc: config string too long\n"); + return -ENOSPC; + } + strcpy(config, opt); + + return 0; +} +__setup("kgdboc=", kgdboc_option_setup); + +static int configure_kgdboc(void) +{ + struct tty_driver *p; + int tty_line = 0; + int err; + + err = kgdboc_option_setup(config); + if (err || !strlen(config) || isspace(config[0])) + goto noconfig; + + err = -ENODEV; + + p = tty_find_polling_driver(config, &tty_line); + if (!p) + goto noconfig; + + kgdb_tty_driver = p; + kgdb_tty_line = tty_line; + + err = kgdb_register_io_module(&kgdboc_io_ops); + if (err) + goto noconfig; + + configured = 1; + + return 0; + +noconfig: + config[0] = 0; + configured = 0; + + return err; +} + +static int init_kgdboc(void) +{ + /* Already configured? */ + if (configured == 1) + return 0; + + return configure_kgdboc(); +} + +static void cleanup_kgdboc(void) +{ + if (configured == 1) + kgdb_unregister_io_module(&kgdboc_io_ops); +} + +static int kgdboc_get_char(void) +{ + return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line); +} + +static void kgdboc_put_char(u8 chr) +{ + kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr); +} + +static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp) +{ + if (strlen(kmessage) >= MAX_KGDBOC_CONFIG_STR) { + printk(KERN_ERR "kgdboc: config string too long\n"); + return -ENOSPC; + } + + /* Only copy in the string if the init function has not run yet */ + if (configured < 0) { + strcpy(config, kmessage); + return 0; + } + + if (kgdb_connected) { + printk(KERN_ERR + "kgdboc: Cannot reconfigure while KGDB is connected.\n"); + + return -EBUSY; + } + + strcpy(config, kmessage); + + if (configured == 1) + cleanup_kgdboc(); + + /* Go and configure with the new params. */ + return configure_kgdboc(); +} + +static void kgdboc_pre_exp_handler(void) +{ + /* Increment the module count when the debugger is active */ + if (!kgdb_connected) + try_module_get(THIS_MODULE); +} + +static void kgdboc_post_exp_handler(void) +{ + /* decrement the module count when the debugger detaches */ + if (!kgdb_connected) + module_put(THIS_MODULE); +} + +static struct kgdb_io kgdboc_io_ops = { + .name = "kgdboc", + .read_char = kgdboc_get_char, + .write_char = kgdboc_put_char, + .pre_exception = kgdboc_pre_exp_handler, + .post_exception = kgdboc_post_exp_handler, +}; + +module_init(init_kgdboc); +module_exit(cleanup_kgdboc); +module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644); +MODULE_PARM_DESC(kgdboc, "[,baud]"); diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 0f5a179..8e6dce3 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1924,7 +1924,12 @@ uart_set_options(struct uart_port *port, struct console *co, port->mctrl |= TIOCM_DTR; port->ops->set_termios(port, &termios, &dummy); - co->cflag = termios.c_cflag; + /* + * Allow the setting of the UART parameters with a NULL console + * too: + */ + if (co) + co->cflag = termios.c_cflag; return 0; } @@ -2182,6 +2187,61 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, } } +#ifdef CONFIG_CONSOLE_POLL + +static int uart_poll_init(struct tty_driver *driver, int line, char *options) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (!state || !state->port) + return -1; + + port = state->port; + if (!(port->ops->poll_get_char && + port->ops->poll_put_char)) + return -1; + + if (options) { + uart_parse_options(options, &baud, &parity, &bits, &flow); + return uart_set_options(port, NULL, baud, parity, bits, flow); + } + + return 0; +} + +static int uart_poll_get_char(struct tty_driver *driver, int line) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + + if (!state || !state->port) + return -1; + + port = state->port; + return port->ops->poll_get_char(port); +} + +static void uart_poll_put_char(struct tty_driver *driver, int line, char ch) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + + if (!state || !state->port) + return; + + port = state->port; + port->ops->poll_put_char(port, ch); +} +#endif + static const struct tty_operations uart_ops = { .open = uart_open, .close = uart_close, @@ -2206,6 +2266,11 @@ static const struct tty_operations uart_ops = { #endif .tiocmget = uart_tiocmget, .tiocmset = uart_tiocmset, +#ifdef CONFIG_CONSOLE_POLL + .poll_init = uart_poll_init, + .poll_get_char = uart_poll_get_char, + .poll_put_char = uart_poll_put_char, +#endif }; /** diff --git a/include/asm-generic/kgdb.h b/include/asm-generic/kgdb.h new file mode 100644 index 0000000..115972e --- /dev/null +++ b/include/asm-generic/kgdb.h @@ -0,0 +1,91 @@ +/* + * This provides the assembly level information so that KGDB can provide + * a GDB that has been patched with enough information to know to stop + * trying to unwind the function. + * + * Author: Tom Rini + * + * 2005 (c) MontaVista Software, Inc. + * 2006 (c) Embedded Alley Solutions, Inc. + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#ifndef __ASM_GENERIC_KGDB_H__ +#define __ASM_GENERIC_KGDB_H__ + +struct pt_regs; + +/** + * kgdb_skipexception - Bail of 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. + */ +int kgdb_skipexception(int exception, struct pt_regs *regs); + +/** + * kgdb_post_master_code - Save error vector/code numbers. + * @regs: Original pt_regs. + * @e_vector: Original error vector. + * @err_code: Original error code. + * + * This is needed on architectures which support SMP and KGDB. + * This function is called after all the slave cpus have been put + * to a know spin state and the master CPU has control over KGDB. + */ +extern void kgdb_post_master_code(struct pt_regs *regs, int e_vector, + int err_code); + +/** + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +extern void kgdb_disable_hw_debug(struct pt_regs *regs); + +#ifdef CONFIG_HAVE_ARCH_KGDB_SHADOW_INFO +/** + * kgdb_shadowinfo - Get shadowed information on @threadid. + * @regs: The &struct pt_regs of the current process. + * @buffer: A buffer of %BUFMAX size. + * @threadid: The thread id of the shadowed process to get information on. + */ +extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, + unsigned threadid); + +/** + * kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id of the shadowed process to get information on. + * + * RETURN: + * This returns a pointer to the &struct task_struct of the shadowed + * thread, @threadid. + */ +extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs, + int threadid); + +/** + * kgdb_shadow_regs - Return the shadowed registers of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id we want the &struct pt_regs for. + * + * RETURN: + * The a pointer to the &struct pt_regs of the shadowed thread @threadid. + */ +extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid); +#else +#define kgdb_shadowinfo(regs, buf, threadid) do { } while (0) +#define kgdb_get_shadow_thread(regs, threadid) NULL +#define kgdb_shadow_regs(regs, threadid) NULL +#endif + +#endif /* __ASM_GENERIC_KGDB_H__ */ diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h new file mode 100644 index 0000000..e0375f6 --- /dev/null +++ b/include/asm-x86/kgdb.h @@ -0,0 +1,85 @@ +#ifdef __KERNEL__ +#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 + +#ifndef __ASSEMBLY__ +static inline void arch_kgdb_breakpoint(void) +{ + asm(" int $3"); +} +# define BREAK_INSTR_SIZE 1 +# define CACHE_FLUSH_IS_SAFE 1 +#endif + +#endif /* _ASM_KGDB_H_ */ +#endif /* __KERNEL__ */ diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h new file mode 100644 index 0000000..ca44c14 --- /dev/null +++ b/include/linux/kgdb.h @@ -0,0 +1,333 @@ +/* + * This provides the callbacks and functions that KGDB needs to share between + * the core, I/O and arch-specific portions. + * + * Author: Amit Kale and + * Tom Rini + * + * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc. + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ +#ifndef _KGDB_H_ +#define _KGDB_H_ + +#include + +#ifdef CONFIG_KGDB + +#include +#include +#include + +#include + +struct pt_regs; + +/* + * kgdb_skipexception - Bail of 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. + */ +int kgdb_skipexception(int exception, struct pt_regs *regs); + +/* + * kgdb_post_master_code - Save error vector/code numbers. + * @regs: Original pt_regs. + * @e_vector: Original error vector. + * @err_code: Original error code. + * + * This is needed on architectures which support SMP and KGDB. + * This function is called after all the slave cpus have been put + * to a know spin state and the master CPU has control over KGDB. + */ +extern void kgdb_post_master_code(struct pt_regs *regs, int e_vector, + int err_code); + +/* + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +extern void kgdb_disable_hw_debug(struct pt_regs *regs); + +#ifdef CONFIG_HAVE_ARCH_KGDB_SHADOW_INFO +/* + * kgdb_shadowinfo - Get shadowed information on @threadid. + * @regs: The &struct pt_regs of the current process. + * @buffer: A buffer of %BUFMAX size. + * @threadid: The thread id of the shadowed process to get information on. + */ +extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, + unsigned threadid); + +/* + * kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id of the shadowed process to get information on. + * + * RETURN: + * This returns a pointer to the &struct task_struct of the shadowed + * thread, @threadid. + */ +extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs, + int threadid); + +/* + * kgdb_shadow_regs - Return the shadowed registers of @threadid. + * @regs: The &struct pt_regs of the current thread. + * @threadid: The thread id we want the &struct pt_regs for. + * + * RETURN: + * The a pointer to the &struct pt_regs of the shadowed thread @threadid. + */ +extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid); +#else +#define kgdb_shadowinfo(regs, buf, threadid) do { } while (0) +#define kgdb_get_shadow_thread(regs, threadid) NULL +#define kgdb_shadow_regs(regs, threadid) NULL +#endif + +struct tasklet_struct; +struct task_struct; +struct uart_port; + +/* To enter the debugger explicitly. */ +void kgdb_breakpoint(void); + +extern int kgdb_connected; +extern int kgdb_may_fault; + +extern atomic_t kgdb_setting_breakpoint; +extern atomic_t cpu_doing_single_step; + +extern struct task_struct *kgdb_usethread; +extern struct task_struct *kgdb_contthread; + +enum kgdb_bptype { + BP_BREAKPOINT = 0, + BP_HARDWARE_BREAKPOINT, + BP_WRITE_WATCHPOINT, + BP_READ_WATCHPOINT, + BP_ACCESS_WATCHPOINT +}; + +enum kgdb_bpstate { + BP_UNDEFINED = 0, + BP_REMOVED, + BP_SET, + BP_ACTIVE +}; + +struct kgdb_bkpt { + unsigned long bpt_addr; + unsigned char saved_instr[BREAK_INSTR_SIZE]; + enum kgdb_bptype type; + enum kgdb_bpstate state; +}; + +/* The maximum number of KGDB I/O modules that can be loaded */ +#define KGDB_MAX_IO_HANDLERS 3 + +#ifndef KGDB_MAX_BREAKPOINTS +# define KGDB_MAX_BREAKPOINTS 1000 +#endif + +#define KGDB_HW_BREAKPOINT 1 + +/* + * Functions each KGDB-supporting architecture must provide: + */ + +/* + * kgdb_arch_init - Perform any architecture specific initalization. + * + * This function will handle the initalization of any architecture + * specific callbacks. + */ +int kgdb_arch_init(void); + +/* + * kgdb_arch_uninit - Perform any architecture specific uninitalization. + * + * This function will handle the uninitalization of any architecture + * specific callbacks, for dynamic registration and unregistration. + */ +void kgdb_arch_uninit(void); + +/* + * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @regs: The &struct pt_regs of the current process. + * + * Convert the pt_regs in @regs into the format for registers that + * GDB expects, stored in @gdb_regs. + */ +void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs); + +/* + * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @p: The &struct task_struct of the desired process. + * + * Convert the register values of the sleeping process in @p to + * the format that GDB expects. + * This function is called when kgdb does not have access to the + * &struct pt_regs and therefore it should fill the gdb registers + * @gdb_regs with what has been saved in &struct thread_struct + * thread field during switch_to. + */ +void +sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p); + +/* + * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. + * @gdb_regs: A pointer to hold the registers we've received from GDB. + * @regs: A pointer to a &struct pt_regs to hold these values in. + * + * Convert the GDB regs in @gdb_regs into the pt_regs, and store them + * in @regs. + */ +void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs); + +/* + * kgdb_arch_handle_exception - Handle architecture specific GDB packets. + * @vector: The error vector of the exception that happened. + * @signo: The signal number of the exception that happened. + * @err_code: The error code of the exception that happened. + * @remcom_in_buffer: The buffer of the packet we have read. + * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. + * @regs: The &struct pt_regs of the current process. + * + * This function MUST handle the 'c' and 's' command packets, + * as well packets to set / remove a hardware breakpoint, if used. + * If there are additional packets which the hardware needs to handle, + * they are handled here. The code should return -1 if it wants to + * process more packets, and a %0 or %1 if it wants to exit from the + * kgdb callback. + */ +int kgdb_arch_handle_exception(int vector, int signo, int err_code, + char *remcom_in_buffer, + char *remcom_out_buffer, + struct pt_regs *regs); + +/* + * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * @flags: Current IRQ state + * + * On SMP systems, we need to get the attention of the other CPUs + * and get them be in a known state. This should do what is needed + * to get the other CPUs to call kgdb_wait(). Note that on some arches, + * the NMI approach is not used for rounding up all the CPUs. For example, + * in case of MIPS, smp_call_function() is used to roundup CPUs. In + * this case, we have to make sure that interrupts are enabled before + * calling smp_call_function(). The argument to this function is + * the flags that will be used when restoring the interrupts. There is + * local_irq_save() call before kgdb_roundup_cpus(). + * + * On non-SMP systems, this is not called. + */ +void kgdb_roundup_cpus(unsigned long flags); + +/* Optional functions. */ +int kgdb_validate_break_address(unsigned long addr); +int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr); +int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle); + +/* + * struct kgdb_arch - Describe architecture specific values. + * @gdb_bpt_instr: The instruction to trigger a breakpoint. + * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT. + * @shadowth: A value of %1 indicates we shadow information on processes. + * @set_breakpoint: Allow an architecture to specify how to set a software + * breakpoint. + * @remove_breakpoint: Allow an architecture to specify how to remove a + * software breakpoint. + * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware + * breakpoint. + * @remove_hw_breakpoint: Allow an architecture to specify how to remove a + * hardware breakpoint. + * @remove_all_hw_break: Allow an architecture to specify how to remove all + * hardware breakpoints. + * @correct_hw_break: Allow an architecture to specify how to correct the + * hardware debug registers. + * + * The @shadowth flag is an option to shadow information not retrievable by + * gdb otherwise. This is deprecated in favor of a binutils which supports + * CFI macros. + */ +struct kgdb_arch { + unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE]; + unsigned long flags; + unsigned shadowth; + + int (*set_breakpoint)(unsigned long, char *); + int (*remove_breakpoint)(unsigned long, char *); + int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); + int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); + void (*remove_all_hw_break)(void); + void (*correct_hw_break)(void); +}; + +/* + * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB. + * @name: Name of the I/O driver. + * @read_char: Pointer to a function that will return one char. + * @write_char: Pointer to a function that will write one char. + * @flush: Pointer to a function that will flush any pending writes. + * @init: Pointer to a function that will initialize the device. + * @late_init: Pointer to a function that will do any setup that has + * other dependencies. + * @pre_exception: Pointer to a function that will do any prep work for + * the I/O driver. + * @post_exception: Pointer to a function that will do any cleanup work + * for the I/O driver. + * + * The @init and @late_init function pointers allow for an I/O driver + * such as a serial driver to fully initialize the port with @init and + * be called very early, yet safely call request_irq() later in the boot + * sequence. + * + * @init is allowed to return a non-0 return value to indicate failure. + * If this is called early on, then KGDB will try again when it would call + * @late_init. If it has failed later in boot as well, the user will be + * notified. + */ +struct kgdb_io { + const char *name; + int (*read_char) (void); + void (*write_char) (u8); + void (*flush) (void); + int (*init) (void); + void (*pre_exception) (void); + void (*post_exception) (void); +}; + +extern struct kgdb_arch arch_kgdb_ops; + +int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops); +void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops); + +int kgdb_hex2long(char **ptr, long *long_val); +char *kgdb_mem2hex(char *mem, char *buf, int count); +char *kgdb_hex2mem(char *buf, char *mem, int count); + +int kgdb_isremovedbreak(unsigned long addr); + +int kgdb_handle_exception(int ex_vector, int signo, int err_code, + struct pt_regs *regs); +int kgdb_nmicallback(int cpu, void *regs); + +extern int kgdb_single_step; +extern atomic_t kgdb_active; + +#endif /* !CONFIG_KGDB */ + +#endif /* _KGDB_H_ */ diff --git a/include/linux/pid.h b/include/linux/pid.h index f84d532..e066d3d 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -86,6 +86,8 @@ extern struct task_struct *FASTCALL(get_pid_task(struct pid *pid, extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type); +extern int pid_max; + /* * attach_pid() and detach_pid() must be called with the tasklist_lock * write-held. diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 1a0b6cf..7d1a46b 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -211,6 +211,10 @@ struct uart_ops { void (*config_port)(struct uart_port *, int); int (*verify_port)(struct uart_port *, struct serial_struct *); int (*ioctl)(struct uart_port *, unsigned int, unsigned long); +#ifdef CONFIG_CONSOLE_POLL + void (*poll_put_char)(struct uart_port *, unsigned char); + int (*poll_get_char)(struct uart_port *); +#endif }; #define UART_CONFIG_TYPE (1 << 0) diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 85c95cd..21f69ac 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -125,6 +125,7 @@ #include struct tty_struct; +struct tty_driver; struct tty_operations { int (*open)(struct tty_struct * tty, struct file * filp); @@ -157,6 +158,11 @@ struct tty_operations { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif }; struct tty_driver { @@ -220,6 +226,11 @@ struct tty_driver { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif struct list_head tty_drivers; }; @@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines); void put_tty_driver(struct tty_driver *driver); void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op); +extern struct tty_driver *tty_find_polling_driver(char *name, int *line); /* tty driver magic number */ #define TTY_DRIVER_MAGIC 0x5402 diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 975c963..98cfe02 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -84,4 +84,26 @@ static inline unsigned long __copy_from_user_nocache(void *to, ret; \ }) +/** + * probe_kernel_write(): safely attempt to write to a location + * @addr: address to write to - its type is type typeof(rdval)* + * @rdval: write to this variable + * + * Safely write to address @addr from variable @rdval. If a kernel fault + * happens, handle that and return -EFAULT. + */ +#define probe_kernel_write(addr, rdval) \ + ({ \ + long ret; \ + mm_segment_t old_fs = get_fs(); \ + \ + set_fs(KERNEL_DS); \ + pagefault_disable(); \ + ret = __put_user(rdval, \ + (__force typeof(rdval) __user *)(addr)); \ + pagefault_enable(); \ + set_fs(old_fs); \ + ret; \ + }) + #endif /* __LINUX_UACCESS_H__ */ diff --git a/kernel/Makefile b/kernel/Makefile index 6c584c5..05c8003 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o obj-$(CONFIG_AUDIT_TREE) += audit_tree.o obj-$(CONFIG_KPROBES) += kprobes.o +obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ obj-$(CONFIG_SECCOMP) += seccomp.o diff --git a/kernel/kgdb.c b/kernel/kgdb.c new file mode 100644 index 0000000..fb4f1a3 --- /dev/null +++ b/kernel/kgdb.c @@ -0,0 +1,2019 @@ +/* + * kernel/kgdb.c + * + * Maintainer: Jason Wessel + * + * Copyright (C) 2000-2001 VERITAS Software Corporation. + * Copyright (C) 2002-2004 Timesys Corporation + * Copyright (C) 2003-2004 Amit S. Kale + * Copyright (C) 2004 Pavel Machek + * Copyright (C) 2004-2006 Tom Rini + * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. + * Copyright (C) 2005-2008 Wind River Systems, Inc. + * Copyright (C) 2007 MontaVista Software, Inc. + * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar + * + * Contributors at various stages not listed above: + * Jason Wessel ( jason.wessel@windriver.com ) + * George Anzinger + * Anurekh Saxena (anurekh.saxena@timesys.com) + * Lake Stevens Instrument Division (Glenn Engel) + * Jim Kingdon, Cygnus Support. + * + * Original KGDB stub: David Grothe , + * Tigran Aivazian + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static int kgdb_break_asap; + +struct kgdb_state { + int all_cpus_synced; + int ex_vector; + int signo; + int err_code; + int cpu; + int pass_exception; + long threadid; + long kgdb_usethreadid; + struct pt_regs *linux_regs; +}; + +static struct debuggerinfo_struct { + void *debuggerinfo; + struct task_struct *task; +} kgdb_info[NR_CPUS]; + +/* + * Could we be about to try and access a bad memory location? + * If so we also need to flag this has happened. + */ +int kgdb_may_fault; + +/* Is a host GDB connected to us? */ +int kgdb_connected; +EXPORT_SYMBOL_GPL(kgdb_connected); + +/* All the KGDB handlers are installed */ +static int kgdb_io_module_registered; + +/* Guard for recursive entry */ +static int exception_level; + +static struct kgdb_io *kgdb_io_ops; +static DEFINE_SPINLOCK(kgdb_registration_lock); + +/* + * Holds information about breakpoints in a kernel. These breakpoints are + * added and removed by gdb. + */ +static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { + [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } +}; + +/* + * KGDB locking is really nasty at places - but we really can only + * do sane debugging if all processors are in a controlled state. + * + * So we go through painful cycles of wait and see, with every + * CPU having a lock: + */ + +/* How many times to count all of the waiting CPUs */ +#define ROUNDUP_WAIT 640000 /* Arbitrary, increase if needed. */ +#define BUF_THREAD_ID_SIZE 16 + +static spinlock_t slave_cpu_locks[NR_CPUS] = { + [0 ... NR_CPUS-1] = __SPIN_LOCK_UNLOCKED(slave_cpu_locks) +}; +static atomic_t cpu_in_kgdb[NR_CPUS]; +atomic_t kgdb_setting_breakpoint; + +struct task_struct *kgdb_usethread; +struct task_struct *kgdb_contthread; + +int kgdb_single_step; +static atomic_t kgdb_sync = ATOMIC_INIT(-1); +atomic_t kgdb_active; + +/* Our I/O buffers. */ +static char remcom_in_buffer[BUFMAX]; +static char remcom_out_buffer[BUFMAX]; + +/* Storage for the registers, in GDB format. */ +static unsigned long gdb_regs[(NUMREGBYTES + + sizeof(unsigned long) - 1) / + sizeof(unsigned long)]; + +/* to keep track of the CPU which is doing the single stepping*/ +atomic_t cpu_doing_single_step = ATOMIC_INIT(-1); + +static int +kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x); + +/* reboot notifier block */ +static struct notifier_block kgdb_reboot_notifier = { + .notifier_call = kgdb_notify_reboot, + .priority = INT_MAX, +}; + +/* + * Finally, some KGDB code :-) + */ + +static char *kgdb_get_mem(char *addr, unsigned char *buf, int count) +{ + while (count) { + if ((unsigned long)addr < TASK_SIZE) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + if (probe_kernel_address(addr, *buf)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + buf++; + addr++; + count--; + } + kgdb_may_fault = 0; + + return NULL; +} + +static char *kgdb_set_mem(char *addr, unsigned char *buf, int count) +{ + while (count) { + if ((unsigned long)addr < TASK_SIZE) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + if (probe_kernel_write(addr, *buf)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + buf++; + addr++; + count--; + } + kgdb_may_fault = 0; + + return NULL; +} + + +/* + * Weak aliases for breakpoint management, + * can be overriden by architectures when needed: + */ +int __weak kgdb_validate_break_address(unsigned long addr) +{ + char tmp_variable[BREAK_INSTR_SIZE]; + + if (!kgdb_get_mem((char *)addr, tmp_variable, BREAK_INSTR_SIZE)) + return 0; + return -1; +} + +int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) +{ + if (kgdb_get_mem((char *)addr, saved_instr, BREAK_INSTR_SIZE)) + return -1; + + if (kgdb_set_mem((char *)addr, arch_kgdb_ops.gdb_bpt_instr, + BREAK_INSTR_SIZE)) + return -1; + return 0; +} + +int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) +{ + if (kgdb_set_mem((char *)addr, (char *)bundle, BREAK_INSTR_SIZE)) + return -1; + return 0; +} + +unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +/* + * GDB remote protocol parser: + */ + +static const char hexchars[] = "0123456789abcdef"; + +static int hex(char ch) +{ + if ((ch >= 'a') && (ch <= 'f')) + return ch - 'a' + 10; + if ((ch >= '0') && (ch <= '9')) + return ch - '0'; + if ((ch >= 'A') && (ch <= 'F')) + return ch - 'A' + 10; + return -1; +} + +/* scan for the sequence $# */ +static void get_packet(char *buffer) +{ + unsigned char checksum; + unsigned char xmitcsum; + int count; + char ch; + + do { + /* + * Spin and wait around for the start character, ignore all + * other characters: + */ + while ((ch = (kgdb_io_ops->read_char())) != '$') + /* nothing */; + + kgdb_connected = 1; + checksum = 0; + xmitcsum = -1; + + count = 0; + + /* + * now, read until a # or end of buffer is found: + */ + while (count < (BUFMAX - 1)) { + ch = kgdb_io_ops->read_char(); + if (ch == '#') + break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = 0; + + if (ch == '#') { + xmitcsum = hex(kgdb_io_ops->read_char()) << 4; + xmitcsum += hex(kgdb_io_ops->read_char()); + + if (checksum != xmitcsum) + /* failed checksum */ + kgdb_io_ops->write_char('-'); + else + /* successful transfer */ + kgdb_io_ops->write_char('+'); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + } + } while (checksum != xmitcsum); +} + +/* + * Send the packet in buffer. + * Check for gdb connection if asked for. + */ +static void put_packet(char *buffer) +{ + unsigned char checksum; + int count; + char ch; + + /* + * $#. + */ + while (1) { + kgdb_io_ops->write_char('$'); + checksum = 0; + count = 0; + + while ((ch = buffer[count])) { + kgdb_io_ops->write_char(ch); + checksum += ch; + count++; + } + + kgdb_io_ops->write_char('#'); + kgdb_io_ops->write_char(hexchars[checksum >> 4]); + kgdb_io_ops->write_char(hexchars[checksum % 16]); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + + /* Now see what we get in reply. */ + ch = kgdb_io_ops->read_char(); + + if (ch == 3) + ch = kgdb_io_ops->read_char(); + + /* If we get an ACK, we are done. */ + if (ch == '+') + return; + + /* + * If we get the start of another packet, this means + * that GDB is attempting to reconnect. We will NAK + * the packet being sent, and stop trying to send this + * packet. + */ + if (ch == '$') { + kgdb_io_ops->write_char('-'); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + return; + } + } +} + +/* + * Fault-tolerant memory accessor wrappers. Performance is a secondary + * concern, the primary concern is not to crash the debugger (or the + * debuggee): + */ + +/* + * Convert the memory pointed to by mem into hex, placing result in buf. + * Return a pointer to the last char put in buf (null). May return an error. + */ +char *kgdb_mem2hex(char *mem, char *buf, int count) +{ + /* + * Accessing some registers in a single load instruction is + * required to avoid bad side effects for some I/O registers. + */ + if ((count == 2) && (((long)mem & 1) == 0)) { + u16 tmp_s; + + if (probe_kernel_address(mem, tmp_s)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + + mem += 2; +#ifdef __BIG_ENDIAN + *buf++ = hexchars[(tmp_s >> 12) & 0xf]; + *buf++ = hexchars[(tmp_s >> 8) & 0xf]; + *buf++ = hexchars[(tmp_s >> 4) & 0xf]; + *buf++ = hexchars[tmp_s & 0xf]; +#else + *buf++ = hexchars[(tmp_s >> 4) & 0xf]; + *buf++ = hexchars[tmp_s & 0xf]; + *buf++ = hexchars[(tmp_s >> 12) & 0xf]; + *buf++ = hexchars[(tmp_s >> 8) & 0xf]; +#endif + } else if ((count == 4) && (((long)mem & 3) == 0)) { + u32 tmp_l; + if (probe_kernel_address(mem, tmp_l)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + + mem += 4; +#ifdef __BIG_ENDIAN + *buf++ = hexchars[(tmp_l >> 28) & 0xf]; + *buf++ = hexchars[(tmp_l >> 24) & 0xf]; + *buf++ = hexchars[(tmp_l >> 20) & 0xf]; + *buf++ = hexchars[(tmp_l >> 16) & 0xf]; + *buf++ = hexchars[(tmp_l >> 12) & 0xf]; + *buf++ = hexchars[(tmp_l >> 8) & 0xf]; + *buf++ = hexchars[(tmp_l >> 4) & 0xf]; + *buf++ = hexchars[tmp_l & 0xf]; +#else + *buf++ = hexchars[(tmp_l >> 4) & 0xf]; + *buf++ = hexchars[tmp_l & 0xf]; + *buf++ = hexchars[(tmp_l >> 12) & 0xf]; + *buf++ = hexchars[(tmp_l >> 8) & 0xf]; + *buf++ = hexchars[(tmp_l >> 20) & 0xf]; + *buf++ = hexchars[(tmp_l >> 16) & 0xf]; + *buf++ = hexchars[(tmp_l >> 28) & 0xf]; + *buf++ = hexchars[(tmp_l >> 24) & 0xf]; +#endif +#ifdef CONFIG_64BIT + } else if ((count == 8) && (((long)mem & 7) == 0)) { + u64 tmp_ll; + if (probe_kernel_address(mem, tmp_ll)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + + mem += 8; +#ifdef __BIG_ENDIAN + *buf++ = hexchars[(tmp_ll >> 60) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 56) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 52) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 48) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 44) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 40) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 36) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 32) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 28) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 24) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 20) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 16) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 12) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 8) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 4) & 0xf]; + *buf++ = hexchars[tmp_ll & 0xf]; +#else + *buf++ = hexchars[(tmp_ll >> 4) & 0xf]; + *buf++ = hexchars[tmp_ll & 0xf]; + *buf++ = hexchars[(tmp_ll >> 12) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 8) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 20) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 16) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 28) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 24) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 36) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 32) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 44) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 40) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 52) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 48) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 60) & 0xf]; + *buf++ = hexchars[(tmp_ll >> 56) & 0xf]; +#endif +#endif + } else { + while (count-- > 0) { + unsigned char ch; + + if (probe_kernel_address(mem, ch)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + mem++; + *buf++ = hexchars[ch >> 4]; + *buf++ = hexchars[ch & 0xf]; + } + } + + kgdb_may_fault = 0; + *buf = 0; + + return buf; +} + +/* + * Copy the binary array pointed to by buf into mem. Fix $, #, and + * 0x7d escaped with 0x7d. Return a pointer to the character after + * the last byte written. + */ +static char *kgdb_ebin2mem(char *buf, char *mem, int count) +{ + for (; count > 0; count--, buf++) { + if (*buf == 0x7d) { + if (probe_kernel_write(mem, (char)(*buf ^ 0x20))) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + buf++; + } else { + if (probe_kernel_write(mem, *buf)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + } + mem++; + } + kgdb_may_fault = 0; + + return mem; +} + +/* + * Convert the hex array pointed to by buf into binary to be placed in mem. + * Return a pointer to the character AFTER the last byte written. + * May return an error. + */ +char *kgdb_hex2mem(char *buf, char *mem, int count) +{ + if ((count == 2) && (((long)mem & 1) == 0)) { + u16 tmp_s = 0; + +#ifdef __BIG_ENDIAN + tmp_s |= hex(*buf++) << 12; + tmp_s |= hex(*buf++) << 8; + tmp_s |= hex(*buf++) << 4; + tmp_s |= hex(*buf++); +#else + tmp_s |= hex(*buf++) << 4; + tmp_s |= hex(*buf++); + tmp_s |= hex(*buf++) << 12; + tmp_s |= hex(*buf++) << 8; +#endif + if (probe_kernel_write(mem, tmp_s)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + mem += 2; + } else if ((count == 4) && (((long)mem & 3) == 0)) { + u32 tmp_l = 0; + +#ifdef __BIG_ENDIAN + tmp_l |= hex(*buf++) << 28; + tmp_l |= hex(*buf++) << 24; + tmp_l |= hex(*buf++) << 20; + tmp_l |= hex(*buf++) << 16; + tmp_l |= hex(*buf++) << 12; + tmp_l |= hex(*buf++) << 8; + tmp_l |= hex(*buf++) << 4; + tmp_l |= hex(*buf++); +#else + tmp_l |= hex(*buf++) << 4; + tmp_l |= hex(*buf++); + tmp_l |= hex(*buf++) << 12; + tmp_l |= hex(*buf++) << 8; + tmp_l |= hex(*buf++) << 20; + tmp_l |= hex(*buf++) << 16; + tmp_l |= hex(*buf++) << 28; + tmp_l |= hex(*buf++) << 24; +#endif + if (probe_kernel_write(mem, tmp_l)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + mem += 4; + } else { + int i; + + for (i = 0; i < count; i++) { + unsigned char ch = hex(*buf++) << 4; + + ch |= hex(*buf++); + if (probe_kernel_write(mem, ch)) { + kgdb_may_fault = 0; + return ERR_PTR(-EINVAL); + } + mem++; + } + } + kgdb_may_fault = 0; + + return mem; +} + +/* + * While we find nice hex chars, build a long_val. + * Return number of chars processed. + */ +int kgdb_hex2long(char **ptr, long *long_val) +{ + int hex_val; + int num = 0; + + *long_val = 0; + + while (**ptr) { + hex_val = hex(**ptr); + if (hex_val >= 0) { + *long_val = (*long_val << 4) | hex_val; + num++; + } else + break; + + (*ptr)++; + } + + return num; +} + +/* Write memory due to an 'M' or 'X' packet. */ +static char *write_mem_msg(int binary) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long addr; + unsigned long length; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && + kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { + if (binary) + ptr = kgdb_ebin2mem(ptr, (char *)addr, length); + else + ptr = kgdb_hex2mem(ptr, (char *)addr, length); + if (IS_ERR(ptr)) + return ptr; + if (CACHE_FLUSH_IS_SAFE) + flush_icache_range(addr, addr + length + 1); + return NULL; + } + + return ERR_PTR(-EINVAL); +} + +static inline char *pack_hex_byte(char *pkt, int byte) +{ + *pkt++ = hexchars[(byte >> 4) & 0xf]; + *pkt++ = hexchars[(byte & 0xf)]; + + return pkt; +} + +static inline void error_packet(char *pkt, int error) +{ + error = -error; + pkt[0] = 'E'; + pkt[1] = hexchars[(error / 10)]; + pkt[2] = hexchars[(error % 10)]; + pkt[3] = '\0'; +} + +/* + * Black magic portion #2. Thread ID accessors. + */ + +static char *pack_threadid(char *pkt, unsigned char *id) +{ + char *limit; + + limit = pkt + BUF_THREAD_ID_SIZE; + while (pkt < limit) + pkt = pack_hex_byte(pkt, *id++); + + return pkt; +} + +static void int_to_threadref(unsigned char *id, int value) +{ + unsigned char *scan; + int i = 4; + + scan = (unsigned char *)id; + while (i--) + *scan++ = 0; + *scan++ = (value >> 24) & 0xff; + *scan++ = (value >> 16) & 0xff; + *scan++ = (value >> 8) & 0xff; + *scan++ = (value & 0xff); +} + +static struct task_struct *getthread(struct pt_regs *regs, int tid) +{ + if (init_pid_ns.last_pid == 0) + return current; + + if (num_online_cpus() && (tid >= pid_max + num_online_cpus() + + arch_kgdb_ops.shadowth)) + return NULL; + + if (arch_kgdb_ops.shadowth && (tid >= pid_max + num_online_cpus())) { + return kgdb_get_shadow_thread(regs, tid - pid_max - + num_online_cpus()); + } + + if (tid >= pid_max) + return idle_task(tid - pid_max); + + if (!tid) + return NULL; + + /* + * find_task_by_pid() does not take the tasklist lock anymore + * but is nicely RCU locked - hence is a pretty resilient + * thing to use: + */ + return find_task_by_pid(tid); +} + +/* + * CPU debug state control: + */ + +#ifdef CONFIG_SMP +static void kgdb_wait(struct pt_regs *regs) +{ + unsigned long flags; + int cpu; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + kgdb_info[cpu].debuggerinfo = regs; + kgdb_info[cpu].task = current; + atomic_set(&cpu_in_kgdb[cpu], 1); + + /* + * The master CPU must be active to enter here, but this is + * gaurd in case the master CPU had not been selected if + * this was an entry via nmi. + */ + while (!atomic_read(&kgdb_active)) + cpu_relax(); + + /* Wait till master CPU goes completely into the debugger. */ + while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active) - 1])) { + int i = 10; /* an arbitrary number. Be nice. A bit. */ + + while (--i) + cpu_relax(); + } + + /* Wait till master CPU is done with debugging */ + spin_lock(&slave_cpu_locks[cpu]); + + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; + + /* fix up hardware debug registers on local cpu */ + if (arch_kgdb_ops.correct_hw_break) + arch_kgdb_ops.correct_hw_break(); + + /* Signal the master CPU that we are done: */ + atomic_set(&cpu_in_kgdb[cpu], 0); + spin_unlock(&slave_cpu_locks[cpu]); + local_irq_restore(flags); +} +#endif + +/* + * SW breakpoint management: + */ +static int kgdb_activate_sw_breakpoints(void) +{ + unsigned long addr; + int error = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_SET) + continue; + + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_set_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + + if (CACHE_FLUSH_IS_SAFE) { + if (current->mm && addr < TASK_SIZE) { + flush_cache_range(current->mm->mmap_cache, + addr, addr + BREAK_INSTR_SIZE); + } else { + flush_icache_range(addr, addr + + BREAK_INSTR_SIZE); + } + } + kgdb_break[i].state = BP_ACTIVE; + } + return 0; +} + +static int kgdb_set_sw_break(unsigned long addr) +{ + int error = kgdb_validate_break_address(addr); + int breakno = -1; + int i; + + if (error < 0) + return error; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) + return -EEXIST; + } + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state == BP_REMOVED && + kgdb_break[i].bpt_addr == addr) { + breakno = i; + break; + } + } + + if (breakno == -1) { + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state == BP_UNDEFINED) { + breakno = i; + break; + } + } + } + + if (breakno == -1) + return -E2BIG; + + kgdb_break[breakno].state = BP_SET; + kgdb_break[breakno].type = BP_BREAKPOINT; + kgdb_break[breakno].bpt_addr = addr; + + return 0; +} + +static int kgdb_deactivate_sw_breakpoints(void) +{ + unsigned long addr; + int error = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_ACTIVE) + continue; + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_remove_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + + if (CACHE_FLUSH_IS_SAFE && current->mm && + addr < TASK_SIZE) { + flush_cache_range(current->mm->mmap_cache, + addr, addr + BREAK_INSTR_SIZE); + } else if (CACHE_FLUSH_IS_SAFE) { + flush_icache_range(addr, addr + BREAK_INSTR_SIZE); + } + kgdb_break[i].state = BP_SET; + } + return 0; +} + +static int kgdb_remove_sw_break(unsigned long addr) +{ + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) { + kgdb_break[i].state = BP_REMOVED; + return 0; + } + } + return -ENOENT; +} + +int kgdb_isremovedbreak(unsigned long addr) +{ + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_REMOVED) && + (kgdb_break[i].bpt_addr == addr)) + return 1; + } + return 0; +} + +int remove_all_break(void) +{ + unsigned long addr; + int error; + int i; + + /* Clear memory breakpoints. */ + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_SET) + continue; + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_remove_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + kgdb_break[i].state = BP_REMOVED; + } + + /* Clear hardware breakpoints. */ + if (arch_kgdb_ops.remove_all_hw_break) + arch_kgdb_ops.remove_all_hw_break(); + + return 0; +} + +static inline int shadow_pid(int realpid) +{ + if (realpid) + return realpid; + + return pid_max + raw_smp_processor_id(); +} + +static char gdbmsgbuf[BUFMAX + 1]; + +static void kgdb_msg_write(const char *s, int len) +{ + char *bufptr; + int wcount; + int i; + + /* 'O'utput */ + gdbmsgbuf[0] = 'O'; + + /* Fill and send buffers... */ + while (len > 0) { + bufptr = gdbmsgbuf + 1; + + /* Calculate how many this time */ + if ((len << 1) > (BUFMAX - 2)) + wcount = (BUFMAX - 2) >> 1; + else + wcount = len; + + /* Pack in hex chars */ + for (i = 0; i < wcount; i++) + bufptr = pack_hex_byte(bufptr, s[i]); + *bufptr = '\0'; + + /* Move up */ + s += wcount; + len -= wcount; + + /* Write packet */ + put_packet(gdbmsgbuf); + } +} + +/* + * Return true if there is a valid kgdb I/O module. Also if no + * debugger is attached a message can be printed to the console about + * waiting for the debugger to attach. + * + * The print_wait argument is only to be true when called from inside + * the core kgdb_handle_exception, because it will wait for the + * debugger to attach. + */ +static int kgdb_io_ready(int print_wait) +{ + if (!kgdb_io_ops) + return 0; + if (kgdb_connected) + return 1; + if (atomic_read(&kgdb_setting_breakpoint)) + return 1; + if (print_wait) + printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); + return 1; +} + +/* + * All the functions that start with gdb_cmd are the various + * operations to implement the handlers for the gdbserial protocol + * where KGDB is communicating with an external debugger + */ + +/* Handle the '?' status packets */ +static void gdb_cmd_status(struct kgdb_state *ks) +{ + /* + * We know that this packet is only sent + * during initial connect. So to be safe, + * we clear out our breakpoints now in case + * GDB is reconnecting. + */ + remove_all_break(); + + /* + * Also, if we haven't been able to roundup all + * CPUs, send an 'O' packet informing the user + * as much. Only need to do this once. + */ + if (!ks->all_cpus_synced) + kgdb_msg_write("Not all CPUs have been synced for KGDB\n", 39); + + remcom_out_buffer[0] = 'S'; + remcom_out_buffer[1] = hexchars[ks->signo >> 4]; + remcom_out_buffer[2] = hexchars[ks->signo % 16]; +} + +/* Handle the 'g' get registers request */ +static void gdb_cmd_getregs(struct kgdb_state *ks) +{ + struct pt_regs *shadowregs; + struct task_struct *thread; + void *local_debuggerinfo; + int i; + + thread = kgdb_usethread; + if (!thread) { + thread = kgdb_info[ks->cpu].task; + local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; + } else { + local_debuggerinfo = NULL; + for (i = 0; i < NR_CPUS; i++) { + /* + * Try to find the task on some other + * or possibly this node if we do not + * find the matching task then we try + * to approximate the results. + */ + if (thread == kgdb_info[i].task) + local_debuggerinfo = kgdb_info[i].debuggerinfo; + } + } + + /* + * All threads that don't have debuggerinfo should be + * in __schedule() sleeping, since all other CPUs + * are in kgdb_wait, and thus have debuggerinfo. + */ + if (arch_kgdb_ops.shadowth && + ks->kgdb_usethreadid >= pid_max + num_online_cpus()) { + + shadowregs = kgdb_shadow_regs(ks->linux_regs, + ks->kgdb_usethreadid - + pid_max - + num_online_cpus()); + if (!shadowregs) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + pt_regs_to_gdb_regs(gdb_regs, shadowregs); + } else { + if (local_debuggerinfo) { + pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); + } else { + /* + * Pull stuff saved during switch_to; nothing + * else is accessible (or even particularly + * relevant). + * + * This should be enough for a stack trace. + */ + sleeping_thread_to_gdb_regs(gdb_regs, thread); + } + } + kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); +} + +/* Handle the 'G' set registers request */ +static void gdb_cmd_setregs(struct kgdb_state *ks) +{ + kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); + + if (kgdb_usethread && kgdb_usethread != current) { + error_packet(remcom_out_buffer, -EINVAL); + } else { + gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); + strcpy(remcom_out_buffer, "OK"); + } +} + +/* Handle the 'm' memory read bytes */ +static void gdb_cmd_memread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long length; + unsigned long addr; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && + kgdb_hex2long(&ptr, &length) > 0) { + + ptr = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); + if (IS_ERR(ptr)) + error_packet(remcom_out_buffer, PTR_ERR(ptr)); + } else { + error_packet(remcom_out_buffer, -EINVAL); + } +} + +/* Handle the 'M' memory write bytes */ +static void gdb_cmd_memwrite(struct kgdb_state *ks) +{ + char *ptr = write_mem_msg(0); + + if (IS_ERR(ptr)) + error_packet(remcom_out_buffer, PTR_ERR(ptr)); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'X' memory binary write bytes */ +static void gdb_cmd_binwrite(struct kgdb_state *ks) +{ + char *ptr = write_mem_msg(1); + + if (IS_ERR(ptr)) + error_packet(remcom_out_buffer, PTR_ERR(ptr)); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'D' or 'k', detach or kill packets */ +static void gdb_cmd_detachkill(struct kgdb_state *ks) +{ + int error; + + /* The detach case */ + if (remcom_in_buffer[0] == 'D') { + error = remove_all_break(); + if (error < 0) { + error_packet(remcom_out_buffer, error); + } else { + strcpy(remcom_out_buffer, "OK"); + kgdb_connected = 0; + } + put_packet(remcom_out_buffer); + } else { + /* + * Assume the kill case, with no exit code checking, + * trying to force detach the debugger: + */ + remove_all_break(); + kgdb_connected = 0; + } +} + +/* Handle the 'R' reboot packets */ +static int gdb_cmd_reboot(struct kgdb_state *ks) +{ + /* For now, only honor R0 */ + if (strcmp(remcom_in_buffer, "R0") == 0) { + printk(KERN_CRIT "Executing reboot\n"); + strcpy(remcom_out_buffer, "OK"); + put_packet(remcom_out_buffer); + emergency_sync(); + + /* + * Execution should not return from + * machine_restart() + */ + machine_restart(NULL); + kgdb_connected = 0; + + return 1; + } + return 0; +} + +/* Handle the 'q' query packets */ +static void gdb_cmd_query(struct kgdb_state *ks) +{ + int numshadowth = num_online_cpus() + arch_kgdb_ops.shadowth; + struct task_struct *thread; + unsigned char thref[8]; + char *ptr; + int i; + + switch (remcom_in_buffer[1]) { + case 's': + case 'f': + if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + + /* + * If we have not yet completed in + * pidhash_init() there isn't much we + * can give back. + */ + if (init_pid_ns.last_pid == 0) { + if (remcom_in_buffer[1] == 'f') + strcpy(remcom_out_buffer, "m0000000000000001"); + break; + } + + if (remcom_in_buffer[1] == 'f') + ks->threadid = 1; + + remcom_out_buffer[0] = 'm'; + ptr = remcom_out_buffer + 1; + + for (i = 0; i < 17 && ks->threadid < pid_max + numshadowth; + ks->threadid++) { + + thread = getthread(ks->linux_regs, ks->threadid); + if (thread) { + int_to_threadref(thref, ks->threadid); + pack_threadid(ptr, thref); + ptr += 16; + *(ptr++) = ','; + i++; + } + } + *(--ptr) = '\0'; + break; + + case 'C': + /* Current thread id */ + strcpy(remcom_out_buffer, "QC"); + ks->threadid = shadow_pid(current->pid); + int_to_threadref(thref, ks->threadid); + pack_threadid(remcom_out_buffer + 2, thref); + break; + case 'T': + if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + ks->threadid = 0; + ptr = remcom_in_buffer + 17; + kgdb_hex2long(&ptr, &ks->threadid); + if (!getthread(ks->linux_regs, ks->threadid)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + if (ks->threadid < pid_max) { + kgdb_mem2hex(getthread(ks->linux_regs, + ks->threadid)->comm, + remcom_out_buffer, 16); + } else { + if (ks->threadid >= pid_max + num_online_cpus()) { + kgdb_shadowinfo(ks->linux_regs, + remcom_out_buffer, + ks->threadid - pid_max - + num_online_cpus()); + } else { + static char tmpstr[23 + BUF_THREAD_ID_SIZE]; + sprintf(tmpstr, "Shadow task %d for pid 0", + (int)(ks->threadid - pid_max)); + kgdb_mem2hex(tmpstr, remcom_out_buffer, + strlen(tmpstr)); + } + } + break; + } +} + +/* Handle the 'H' task query packets */ +static void gdb_cmd_task(struct kgdb_state *ks) +{ + struct task_struct *thread; + char *ptr; + + switch (remcom_in_buffer[1]) { + case 'g': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_usethread = thread; + ks->kgdb_usethreadid = ks->threadid; + strcpy(remcom_out_buffer, "OK"); + break; + case 'c': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + if (!ks->threadid) { + kgdb_contthread = NULL; + } else { + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_contthread = thread; + } + strcpy(remcom_out_buffer, "OK"); + break; + } +} + +/* Handle the 'T' thread query packets */ +static void gdb_cmd_thread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + struct task_struct *thread; + + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (thread) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, -EINVAL); +} + +/* Handle the 'z' or 'Z' breakpoint remove or set packets */ +static void gdb_cmd_break(struct kgdb_state *ks) +{ + /* + * Since GDB-5.3, it's been drafted that '0' is a software + * breakpoint, '1' is a hardware breakpoint, so let's do that. + */ + char *bpt_type = &remcom_in_buffer[1]; + char *ptr = &remcom_in_buffer[2]; + unsigned long addr; + unsigned long length; + int error = 0; + + if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { + /* Unsupported */ + if (*bpt_type > '4') + return; + } else { + if (*bpt_type != '0' && *bpt_type != '1') + /* Unsupported. */ + return; + } + + /* + * Test if this is a hardware breakpoint, and + * if we support it: + */ + if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) + /* Unsupported. */ + return; + + if (*(ptr++) != ',') { + error_packet(remcom_out_buffer, -EINVAL); + return; + } else { + if (kgdb_hex2long(&ptr, &addr)) { + if (*(ptr++) != ',' || + !kgdb_hex2long(&ptr, &length)) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + } else { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + } + + if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') + error = kgdb_set_sw_break(addr); + else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') + error = kgdb_remove_sw_break(addr); + else if (remcom_in_buffer[0] == 'Z') + error = arch_kgdb_ops.set_hw_breakpoint(addr, + (int)length, *bpt_type); + else if (remcom_in_buffer[0] == 'z') + error = arch_kgdb_ops.remove_hw_breakpoint(addr, + (int) length, *bpt_type); + + if (error == 0) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, error); +} + +/* Handle the 'C' signal / exception passing packets */ +static int gdb_cmd_exception_pass(struct kgdb_state *ks) +{ + /* C09 == pass exception + * C15 == detach kgdb, pass exception + */ + if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'c'; + + } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'D'; + remove_all_break(); + kgdb_connected = 0; + return 1; + + } else { + error_packet(remcom_out_buffer, -EINVAL); + return 0; + } + + /* Indicate fall through */ + return -1; +} + +/* + * This function performs all gdbserial command procesing + */ +static int gdb_serial_stub(struct kgdb_state *ks) +{ + int error = 0; + int tmp; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + if (kgdb_connected) { + unsigned char thref[8]; + char *ptr; + + /* + * Warn debugger if the CPUs are not synced with an 'O' + * packet: + */ + if (!ks->all_cpus_synced) { + kgdb_msg_write("Not all CPUs have been synced for " + "KGDB\n", 39); + } + /* Reply to host that an exception has occurred */ + ptr = remcom_out_buffer; + *ptr++ = 'T'; + *ptr++ = hexchars[(ks->signo >> 4) % 16]; + *ptr++ = hexchars[ks->signo % 16]; + ptr += strlen(strcpy(ptr, "thread:")); + int_to_threadref(thref, shadow_pid(current->pid)); + ptr = pack_threadid(ptr, thref); + *ptr++ = ';'; + put_packet(remcom_out_buffer); + } + + kgdb_usethread = kgdb_info[ks->cpu].task; + ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); + ks->pass_exception = 0; + + while (1) { + error = 0; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + get_packet(remcom_in_buffer); + + switch (remcom_in_buffer[0]) { + case '?': /* gdbserial status */ + gdb_cmd_status(ks); + break; + case 'g': /* return the value of the CPU registers */ + gdb_cmd_getregs(ks); + break; + case 'G': /* set the value of the CPU registers - return OK */ + gdb_cmd_setregs(ks); + break; + case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ + gdb_cmd_memread(ks); + break; + case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_memwrite(ks); + break; + case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_binwrite(ks); + break; + /* kill or detach. KGDB should treat this like a + * continue. + */ + case 'D': /* Debugger detach */ + case 'k': /* Debugger detach via kill */ + gdb_cmd_detachkill(ks); + goto default_handle; + case 'R': /* Reboot */ + if (gdb_cmd_reboot(ks)) + goto default_handle; + break; + case 'q': /* query command */ + gdb_cmd_query(ks); + break; + case 'H': /* task related */ + gdb_cmd_task(ks); + break; + case 'T': /* Query thread status */ + gdb_cmd_thread(ks); + break; + case 'z': /* Break point remove */ + case 'Z': /* Break point set */ + gdb_cmd_break(ks); + break; + case 'C': /* Exception passing */ + tmp = gdb_cmd_exception_pass(ks); + if (tmp > 0) + goto default_handle; + if (tmp == 0) + break; + /* Fall through on tmp < 0 */ + case 'c': /* Continue packet */ + case 's': /* Single step packet */ + if (kgdb_contthread && kgdb_contthread != current) { + /* Can't switch threads in kgdb */ + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_activate_sw_breakpoints(); + /* Fall through to default processing */ + default: +default_handle: + error = kgdb_arch_handle_exception(ks->ex_vector, + ks->signo, + ks->err_code, + remcom_in_buffer, + remcom_out_buffer, + ks->linux_regs); + /* + * Leave cmd processing on error, detach, + * kill, continue, or single step. + */ + if (error >= 0 || remcom_in_buffer[0] == 'D' || + remcom_in_buffer[0] == 'k') { + error = 0; + goto kgdb_exit; + } + + } + + /* reply to the request */ + put_packet(remcom_out_buffer); + } + +kgdb_exit: + if (ks->pass_exception) + error = 1; + return error; +} + +static int kgdb_reenter_check(struct kgdb_state *ks) +{ + unsigned long addr; + + if (atomic_read(&kgdb_active) != raw_smp_processor_id() + 1) + return 0; + + /* Panic on recursive debugger calls: */ + exception_level++; + addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); + kgdb_deactivate_sw_breakpoints(); + + /* + * If the break point removed ok at the place exception + * occurred, try to recover and print a warning to the end + * user because the user planted a breakpoint in a place that + * KGDB needs in order to function. + */ + if (kgdb_remove_sw_break(addr) == 0) { + exception_level = 0; + kgdb_skipexception(ks->ex_vector, ks->linux_regs); + kgdb_activate_sw_breakpoints(); + printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n"); + WARN_ON_ONCE(1); + + return 1; + } + remove_all_break(); + kgdb_skipexception(ks->ex_vector, ks->linux_regs); + + if (exception_level > 1) { + dump_stack(); + panic("Recursive entry to debugger"); + } + + printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); + dump_stack(); + panic("Recursive entry to debugger"); + + return 1; +} + +/* + * kgdb_handle_exception() - main entry point from a kernel exception + * + * Locking hierarchy: + * interface locks, if any (begin_session) + * kgdb lock (kgdb_active) + * + * Note that since we can be in here prior to our cpumask being filled + * out, we err on the side of caution and loop over NR_CPUS instead + * of a for_each_online_cpu. + */ +int +kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) +{ + struct kgdb_state kgdb_var; + struct kgdb_state *ks = &kgdb_var; + unsigned long flags; + int error = 0; + int i, cpu; + + ks->cpu = raw_smp_processor_id(); + ks->all_cpus_synced = 0; + ks->ex_vector = evector; + ks->signo = signo; + ks->ex_vector = evector; + ks->err_code = ecode; + ks->kgdb_usethreadid = 0; + ks->linux_regs = regs; + + if (kgdb_reenter_check(ks)) + return 0; /* Ouch, double exception ! */ + +acquirelock: + /* + * Interrupts will be restored by the 'trap return' code, except when + * single stepping. + */ + local_irq_save(flags); + + cpu = raw_smp_processor_id(); + + /* + * Being the process of declaring a master debug processor, the + * goal is to have only one single processor set kgdb_active + * to the number of the cpu + 1. The atomic variable kgdb_sync is + * used to control the selection. + */ + while (1) { + i = 25; /* an arbitrary number */ + if (atomic_read(&kgdb_sync) < 0 && + atomic_inc_and_test(&kgdb_sync)) { + atomic_set(&kgdb_active, cpu + 1); + break; + } + + while (--i) + cpu_relax(); + + if (atomic_read(&cpu_doing_single_step) != -1 && + atomic_read(&cpu_doing_single_step) != cpu) + udelay(1); + } + + /* + * Do not start the debugger connection on this CPU if the last + * instance of the exception handler wanted to come into the + * debugger on a different CPU via a single step + */ + if (atomic_read(&cpu_doing_single_step) != -1 && + atomic_read(&cpu_doing_single_step) != cpu) { + + atomic_set(&kgdb_active, 0); + atomic_set(&kgdb_sync, -1); + local_irq_restore(flags); + + goto acquirelock; + } + + if (!kgdb_io_ready(1)) { + error = 1; + goto kgdb_restore; /* No I/O connection, so resume the system */ + } + + /* + * Don't enter if we have hit a removed breakpoint. + */ + if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) + goto kgdb_restore; + + /* Call the I/O driver's pre_exception routine */ + if (kgdb_io_ops->pre_exception) + kgdb_io_ops->pre_exception(); + + kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs; + kgdb_info[ks->cpu].task = current; + + kgdb_disable_hw_debug(ks->linux_regs); + + /* + * Get the slave CPU lock which will hold all the non-master + * CPU in a spin state while the debugger is active + */ + if (!kgdb_single_step || !kgdb_contthread) { + for (i = 0; i < NR_CPUS; i++) + spin_lock(&slave_cpu_locks[i]); + } + +#ifdef CONFIG_SMP + /* Signal the other CPUs to enter kgdb_wait() */ + if (!kgdb_single_step || !kgdb_contthread) + kgdb_roundup_cpus(flags); +#endif + + /* + * spin_lock code is good enough as a barrier so we don't + * need one here: + */ + atomic_set(&cpu_in_kgdb[ks->cpu], 1); + + /* + * Wait a reasonable time for the other CPUs to be notified and + * be waiting for us. Very early on this could be imperfect + * as num_online_cpus() could be 0. + */ + for (i = 0; i < ROUNDUP_WAIT; i++) { + int num = 0; + int n; + + for (n = 0; n < NR_CPUS; n++) { + if (atomic_read(&cpu_in_kgdb[n])) + num++; + } + if (num >= num_online_cpus()) { + ks->all_cpus_synced = 1; + break; + } + } + + /* Master processor is completely in the debugger */ + kgdb_post_master_code(ks->linux_regs, ks->ex_vector, ks->err_code); + kgdb_deactivate_sw_breakpoints(); + kgdb_single_step = 0; + kgdb_contthread = NULL; + exception_level = 0; + + /* Talk to debugger with gdbserial protocol */ + error = gdb_serial_stub(ks); + + /* Call the I/O driver's post_exception routine */ + if (kgdb_io_ops->post_exception) + kgdb_io_ops->post_exception(); + + kgdb_info[ks->cpu].debuggerinfo = NULL; + kgdb_info[ks->cpu].task = NULL; + atomic_set(&cpu_in_kgdb[ks->cpu], 0); + + if (!kgdb_single_step || !kgdb_contthread) { + for (i = NR_CPUS-1; i >= 0; i--) + spin_unlock(&slave_cpu_locks[i]); + /* + * Wait till all the CPUs have quit + * from the debugger. + */ + for (i = 0; i < NR_CPUS; i++) { + while (atomic_read(&cpu_in_kgdb[i])) { + int j = 10; /* an arbitrary number */ + + while (--j) + cpu_relax(); + } + } + } + +#ifdef CONFIG_SMP + /* + * This delay has a real purpose. The problem is that if you + * are single-stepping, you are sending an NMI to all the + * other CPUs to stop them. Interrupts come in, but don't get + * handled. Then you let them go just long enough to get into + * their interrupt routines and use up some stack. You stop them + * again, and then do the same thing. After a while you blow + * the stack on the other CPUs. This delay gives some time for + * interrupts to be cleared out on the other CPUs. + */ + if (kgdb_single_step) + mdelay(2); +#endif +kgdb_restore: + /* Free kgdb_active */ + atomic_set(&kgdb_active, 0); + atomic_set(&kgdb_sync, -1); + local_irq_restore(flags); + + return error; +} + +/* + * GDB places a breakpoint at this function to know dynamically + * loaded objects. It's not defined static so that only one instance with this + * name exists in the kernel. + */ + +int module_event(struct notifier_block *self, unsigned long val, void *data) +{ + return 0; +} + +static struct notifier_block kgdb_module_load_nb = { + .notifier_call = module_event, +}; + +int kgdb_nmicallback(int cpu, void *regs) +{ +#ifdef CONFIG_SMP + if (!atomic_read(&cpu_in_kgdb[cpu]) && + atomic_read(&kgdb_active) != (cpu + 1)) { + kgdb_wait((struct pt_regs *)regs); + return 0; + } +#endif + return 1; +} + +/* + * This is called when a panic happens. All we need to do is + * kgdb_breakpoint(). + */ +static int +kgdb_panic_notify(struct notifier_block *self, unsigned long cmd, void *ptr) +{ + if (atomic_read(&kgdb_active) != 0) { + printk(KERN_ERR "KGDB: Cannot handle panic while" + "debugger active\n"); + dump_stack(); + return NOTIFY_DONE; + } + printk(KERN_ERR "kgdb panic point\n"); + kgdb_breakpoint(); + + return NOTIFY_DONE; +} + +static struct notifier_block kgdb_panic_notifier = { + .notifier_call = kgdb_panic_notify, +}; + +#ifdef CONFIG_KGDB_CONSOLE_OUTPUT + +void kgdb_console_write(struct console *co, const char *s, unsigned count) +{ + unsigned long flags; + + /* If we're debugging, or KGDB has not connected, don't try + * and print. */ + if (!kgdb_connected || atomic_read(&kgdb_active) != 0) + return; + + local_irq_save(flags); + kgdb_msg_write(s, count); + local_irq_restore(flags); +} + +static struct console kgdbcons = { + .name = "kgdb", + .write = kgdb_console_write, + .flags = CON_PRINTBUFFER | CON_ENABLED, + .index = -1, +} +; +#endif + +#ifdef CONFIG_MAGIC_SYSRQ +static void sysrq_handle_gdb(int key, struct tty_struct *tty) +{ + if (!kgdb_io_ops) { + printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); + return; + } + if (!kgdb_connected) + printk(KERN_CRIT "Entering KGDB\n"); + + kgdb_breakpoint(); +} + +static struct sysrq_key_op sysrq_gdb_op = { + .handler = sysrq_handle_gdb, + .help_msg = "Gdb", + .action_msg = "GDB", +}; +#endif + +static void kgdb_register_callbacks(void) +{ + if (!kgdb_io_module_registered) { + kgdb_io_module_registered = 1; + kgdb_arch_init(); + atomic_notifier_chain_register(&panic_notifier_list, + &kgdb_panic_notifier); + register_module_notifier(&kgdb_module_load_nb); + register_reboot_notifier(&kgdb_reboot_notifier); +#ifdef CONFIG_MAGIC_SYSRQ + register_sysrq_key('g', &sysrq_gdb_op); +#endif +#ifdef CONFIG_KGDB_CONSOLE_OUTPUT + /* Initialize the console registration */ + register_console(&kgdbcons); +#endif + } +} + +static void kgdb_unregister_callbacks(void) +{ + /* + * When this routine is called KGDB should unregister from the + * panic handler and clean up, making sure it is not handling any + * break exceptions at the time. + */ + if (kgdb_io_module_registered) { + kgdb_io_module_registered = 0; + kgdb_arch_uninit(); + atomic_notifier_chain_unregister(&panic_notifier_list, + &kgdb_panic_notifier); + unregister_module_notifier(&kgdb_module_load_nb); + unregister_reboot_notifier(&kgdb_reboot_notifier); +#ifdef CONFIG_MAGIC_SYSRQ + unregister_sysrq_key('g', &sysrq_gdb_op); +#endif +#ifdef CONFIG_KGDB_CONSOLE_OUTPUT + /* Initialize the console registration */ + unregister_console(&kgdbcons); +#endif + } +} + +static void kgdb_initial_breakpoint(void) +{ + kgdb_break_asap = 0; + + printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); + kgdb_breakpoint(); +} + +int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) +{ + int err; + + spin_lock(&kgdb_registration_lock); + + if (kgdb_io_ops) { + spin_unlock(&kgdb_registration_lock); + + printk(KERN_ERR "kgdb: Another I/O driver is already " + "registered with KGDB.\n"); + return -EBUSY; + } + + if (new_kgdb_io_ops->init) { + err = new_kgdb_io_ops->init(); + if (err) { + spin_unlock(&kgdb_registration_lock); + return err; + } + } + + kgdb_io_ops = new_kgdb_io_ops; + + spin_unlock(&kgdb_registration_lock); + + printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", + new_kgdb_io_ops->name); + + /* Arm KGDB now. */ + kgdb_register_callbacks(); + + if (kgdb_break_asap) + kgdb_initial_breakpoint(); + + return 0; +} +EXPORT_SYMBOL_GPL(kgdb_register_io_module); + +void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) +{ + BUG_ON(kgdb_connected); + + /* + * KGDB is no longer able to communicate out, so + * unregister our callbacks and reset state. + */ + kgdb_unregister_callbacks(); + + spin_lock(&kgdb_registration_lock); + + WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); + kgdb_io_ops = NULL; + + spin_unlock(&kgdb_registration_lock); + + printk(KERN_INFO + "kgdb: Unregistered I/O driver %s, debugger disabled.\n", + old_kgdb_io_ops->name); +} +EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); + +/* + * This function will generate a breakpoint exception. It is used at the + * beginning of a program to sync up with a debugger and can be used + * otherwise as a quick means to stop program execution and "break" into + * the debugger. + */ +void kgdb_breakpoint(void) +{ + atomic_set(&kgdb_setting_breakpoint, 1); + wmb(); /* Sync point before breakpoint */ + arch_kgdb_breakpoint(); + wmb(); /* Sync point after breakpoint */ + atomic_set(&kgdb_setting_breakpoint, 0); +} +EXPORT_SYMBOL_GPL(kgdb_breakpoint); + +static int +kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x) +{ + unsigned long flags; + + /* + * If we're debugging, or KGDB has not connected, don't try + * and print: + */ + if (!kgdb_connected || atomic_read(&kgdb_active) != 0) + return 0; + + if (code == SYS_RESTART || code == SYS_HALT || code == SYS_POWER_OFF) { + local_irq_save(flags); + put_packet("X00"); + kgdb_connected = 0; + local_irq_restore(flags); + } + return NOTIFY_DONE; +} + +static int __init opt_kgdb_wait(char *str) +{ + kgdb_break_asap = 1; + + if (kgdb_io_module_registered) + kgdb_initial_breakpoint(); + + return 0; +} + +early_param("kgdbwait", opt_kgdb_wait); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index d41ef6b..97a152c 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -71,7 +72,6 @@ extern int max_threads; extern int core_uses_pid; extern int suid_dumpable; extern char core_pattern[]; -extern int pid_max; extern int min_free_kbytes; extern int pid_max_min, pid_max_max; extern int sysctl_drop_caches; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a370fe8..a904916 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -618,3 +618,5 @@ config PROVIDE_OHCI1394_DMA_INIT See Documentation/debugging-via-ohci1394.txt for more information. source "samples/Kconfig" + +source "lib/Kconfig.kgdb" diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb new file mode 100644 index 0000000..00263c0 --- /dev/null +++ b/lib/Kconfig.kgdb @@ -0,0 +1,37 @@ + +menuconfig KGDB + bool "KGDB: kernel debugging with remote gdb" + select FRAME_POINTER + depends on HAVE_ARCH_KGDB + depends on DEBUG_KERNEL && EXPERIMENTAL + help + If you say Y here, it will be possible to remotely debug the + kernel using gdb. Documentation of kernel debugger is available + at http://kgdb.sourceforge.net as well as in DocBook form + in Documentation/DocBook/. If unsure, say N. + +config HAVE_ARCH_KGDB_SHADOW_INFO + bool + +config KGDB_CONSOLE_OUTPUT + bool "KGDB: Console messages through gdb" + depends on KGDB + help + If you say Y here, console messages will appear through gdb. + Other consoles such as tty or ttyS will continue to work as usual. + Note that if you use this in conjunction with KGDBOE, if the + ethernet driver runs into an error condition during use with KGDB, + it is possible to hit an infinite recursion, causing the kernel + to crash, and typically reboot. For this reason, it is preferable + to use NETCONSOLE in conjunction with KGDBOE instead of + KGDB_CONSOLE. + +config KGDBOC + tristate "KGDB: use kgdb over the serial console" + depends on KGDB + select CONSOLE_POLL + select MAGIC_SYSRQ + default y + help + Share a serial console with kgdb. Sysrq-g must be used + to break in initially. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/