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-rw-r--r--arch/x86/kernel/kgdb.c567
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diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
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+/*
+ * 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;
+ if (kgdb_contthread) {
+ 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() &&
+ 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;
+
+ /* 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,
+};
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-30 01:57:24 +0000