| /* |
| * 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 <amitkale@linsyssoft.com> |
| * 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<akale@veritas.com> |
| * Updated by: Tom Rini <trini@kernel.crashing.org> |
| * Updated by: Jason Wessel <jason.wessel@windriver.com> |
| * Modified for 386 by Jim Kingdon, Cygnus Support. |
| * Origianl kgdb, compatibility with 2.1.xx kernel by |
| * David Grothe <dave@gcom.com> |
| * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com> |
| * X86_64 changes from Andi Kleen's patch merged by Jim Houston |
| */ |
| #include <linux/spinlock.h> |
| #include <linux/kdebug.h> |
| #include <linux/string.h> |
| #include <linux/kernel.h> |
| #include <linux/ptrace.h> |
| #include <linux/sched.h> |
| #include <linux/delay.h> |
| #include <linux/kgdb.h> |
| #include <linux/init.h> |
| #include <linux/smp.h> |
| #include <linux/nmi.h> |
| |
| #include <asm/apicdef.h> |
| #include <asm/system.h> |
| |
| #include <mach_ipi.h> |
| |
| /* |
| * 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]; |
| |
| 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); |
| if (breakno >= 0 && breakno <= 3) |
| set_debugreg(breakinfo[breakno].addr, breakno); |
| |
| } 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_primary_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 primary CPU has control over KGDB. |
| */ |
| void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) |
| { |
| /* primary 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; |
| case 'D': |
| case 'k': |
| newPC = linux_regs->ip; |
| |
| /* clear the trace bit */ |
| linux_regs->flags &= ~X86_EFLAGS_TF; |
| atomic_set(&kgdb_cpu_doing_single_step, -1); |
| |
| /* set the trace bit if we're stepping */ |
| if (remcomInBuffer[0] == 's') { |
| linux_regs->flags |= X86_EFLAGS_TF; |
| kgdb_single_step = 1; |
| atomic_set(&kgdb_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; |
| } |
| |
| 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 was_in_debug_nmi[NR_CPUS]; |
| |
| static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
| { |
| struct pt_regs *regs = args->regs; |
| |
| switch (cmd) { |
| case DIE_NMI: |
| if (atomic_read(&kgdb_active) != -1) { |
| /* KGDB CPU roundup */ |
| kgdb_nmicallback(raw_smp_processor_id(), regs); |
| was_in_debug_nmi[raw_smp_processor_id()] = 1; |
| touch_nmi_watchdog(); |
| return NOTIFY_STOP; |
| } |
| return NOTIFY_DONE; |
| |
| case DIE_NMI_IPI: |
| if (atomic_read(&kgdb_active) != -1) { |
| /* KGDB CPU roundup */ |
| kgdb_nmicallback(raw_smp_processor_id(), regs); |
| was_in_debug_nmi[raw_smp_processor_id()] = 1; |
| touch_nmi_watchdog(); |
| } |
| return NOTIFY_DONE; |
| |
| case DIE_NMIUNKNOWN: |
| if (was_in_debug_nmi[raw_smp_processor_id()]) { |
| was_in_debug_nmi[raw_smp_processor_id()] = 0; |
| return NOTIFY_STOP; |
| } |
| return NOTIFY_DONE; |
| |
| case DIE_NMIWATCHDOG: |
| if (atomic_read(&kgdb_active) != -1) { |
| /* KGDB CPU roundup: */ |
| kgdb_nmicallback(raw_smp_processor_id(), regs); |
| return NOTIFY_STOP; |
| } |
| /* Enter debugger: */ |
| break; |
| |
| case DIE_DEBUG: |
| if (atomic_read(&kgdb_cpu_doing_single_step) == |
| raw_smp_processor_id()) { |
| if (user_mode(regs)) |
| return single_step_cont(regs, args); |
| break; |
| } else if (test_thread_flag(TIF_SINGLESTEP)) |
| /* This means a user thread is single stepping |
| * a system call which should be ignored |
| */ |
| return NOTIFY_DONE; |
| /* fall through */ |
| default: |
| if (user_mode(regs)) |
| return NOTIFY_DONE; |
| } |
| |
| if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) |
| return NOTIFY_DONE; |
| |
| /* Must touch watchdog before return to normal operation */ |
| touch_nmi_watchdog(); |
| return NOTIFY_STOP; |
| } |
| |
| static int |
| kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) |
| { |
| unsigned long flags; |
| int ret; |
| |
| local_irq_save(flags); |
| ret = __kgdb_notify(ptr, cmd); |
| local_irq_restore(flags); |
| |
| return ret; |
| } |
| |
| static struct notifier_block kgdb_notifier = { |
| .notifier_call = kgdb_notify, |
| |
| /* |
| * Lowest-prio notifier priority, we want to be notified last: |
| */ |
| .priority = -INT_MAX, |
| }; |
| |
| /** |
| * kgdb_arch_init - Perform any architecture specific initalization. |
| * |
| * This function will handle the initalization of any architecture |
| * specific callbacks. |
| */ |
| int kgdb_arch_init(void) |
| { |
| return register_die_notifier(&kgdb_notifier); |
| } |
| |
| /** |
| * kgdb_arch_exit - Perform any architecture specific uninitalization. |
| * |
| * This function will handle the uninitalization of any architecture |
| * specific callbacks, for dynamic registration and unregistration. |
| */ |
| void kgdb_arch_exit(void) |
| { |
| unregister_die_notifier(&kgdb_notifier); |
| } |
| |
| /** |
| * |
| * kgdb_skipexception - Bail out of KGDB when we've been triggered. |
| * @exception: Exception vector number |
| * @regs: Current &struct pt_regs. |
| * |
| * On some architectures we need to skip a breakpoint exception when |
| * it occurs after a breakpoint has been removed. |
| * |
| * Skip an int3 exception when it occurs after a breakpoint has been |
| * removed. Backtrack eip by 1 since the int3 would have caused it to |
| * increment by 1. |
| */ |
| int kgdb_skipexception(int exception, struct pt_regs *regs) |
| { |
| if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { |
| regs->ip -= 1; |
| return 1; |
| } |
| return 0; |
| } |
| |
| unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) |
| { |
| if (exception == 3) |
| return instruction_pointer(regs) - 1; |
| return instruction_pointer(regs); |
| } |
| |
| struct kgdb_arch arch_kgdb_ops = { |
| /* Breakpoint instruction: */ |
| .gdb_bpt_instr = { 0xcc }, |
| .flags = KGDB_HW_BREAKPOINT, |
| .set_hw_breakpoint = kgdb_set_hw_break, |
| .remove_hw_breakpoint = kgdb_remove_hw_break, |
| .remove_all_hw_break = kgdb_remove_all_hw_break, |
| .correct_hw_break = kgdb_correct_hw_break, |
| }; |