File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
new file mode 100644
index 0000000..44256a6
--- /dev/null
+++ b/arch/x86/kernel/kgdb.c
@@ -0,0 +1,819 @@
+/*
+ * 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/smp.h>
+#include <linux/nmi.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/uaccess.h>
+#include <linux/memory.h>
+
+#include <asm/debugreg.h>
+#include <asm/apicdef.h>
+#include <asm/apic.h>
+#include <asm/nmi.h>
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+#ifdef CONFIG_X86_32
+ { "ax", 4, offsetof(struct pt_regs, ax) },
+ { "cx", 4, offsetof(struct pt_regs, cx) },
+ { "dx", 4, offsetof(struct pt_regs, dx) },
+ { "bx", 4, offsetof(struct pt_regs, bx) },
+ { "sp", 4, offsetof(struct pt_regs, sp) },
+ { "bp", 4, offsetof(struct pt_regs, bp) },
+ { "si", 4, offsetof(struct pt_regs, si) },
+ { "di", 4, offsetof(struct pt_regs, di) },
+ { "ip", 4, offsetof(struct pt_regs, ip) },
+ { "flags", 4, offsetof(struct pt_regs, flags) },
+ { "cs", 4, offsetof(struct pt_regs, cs) },
+ { "ss", 4, offsetof(struct pt_regs, ss) },
+ { "ds", 4, offsetof(struct pt_regs, ds) },
+ { "es", 4, offsetof(struct pt_regs, es) },
+#else
+ { "ax", 8, offsetof(struct pt_regs, ax) },
+ { "bx", 8, offsetof(struct pt_regs, bx) },
+ { "cx", 8, offsetof(struct pt_regs, cx) },
+ { "dx", 8, offsetof(struct pt_regs, dx) },
+ { "si", 8, offsetof(struct pt_regs, si) },
+ { "di", 8, offsetof(struct pt_regs, di) },
+ { "bp", 8, offsetof(struct pt_regs, bp) },
+ { "sp", 8, offsetof(struct pt_regs, sp) },
+ { "r8", 8, offsetof(struct pt_regs, r8) },
+ { "r9", 8, offsetof(struct pt_regs, r9) },
+ { "r10", 8, offsetof(struct pt_regs, r10) },
+ { "r11", 8, offsetof(struct pt_regs, r11) },
+ { "r12", 8, offsetof(struct pt_regs, r12) },
+ { "r13", 8, offsetof(struct pt_regs, r13) },
+ { "r14", 8, offsetof(struct pt_regs, r14) },
+ { "r15", 8, offsetof(struct pt_regs, r15) },
+ { "ip", 8, offsetof(struct pt_regs, ip) },
+ { "flags", 4, offsetof(struct pt_regs, flags) },
+ { "cs", 4, offsetof(struct pt_regs, cs) },
+ { "ss", 4, offsetof(struct pt_regs, ss) },
+ { "ds", 4, -1 },
+ { "es", 4, -1 },
+#endif
+ { "fs", 4, -1 },
+ { "gs", 4, -1 },
+};
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (
+#ifdef CONFIG_X86_32
+ regno == GDB_SS || regno == GDB_FS || regno == GDB_GS ||
+#endif
+ regno == GDB_SP || regno == GDB_ORIG_AX)
+ return 0;
+
+ if (dbg_reg_def[regno].offset != -1)
+ memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+ dbg_reg_def[regno].size);
+ return 0;
+}
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno == GDB_ORIG_AX) {
+ memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax));
+ return "orig_ax";
+ }
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return NULL;
+
+ if (dbg_reg_def[regno].offset != -1)
+ memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+ dbg_reg_def[regno].size);
+
+#ifdef CONFIG_X86_32
+ switch (regno) {
+ case GDB_SS:
+ if (!user_mode(regs))
+ *(unsigned long *)mem = __KERNEL_DS;
+ break;
+ case GDB_SP:
+ if (!user_mode(regs))
+ *(unsigned long *)mem = kernel_stack_pointer(regs);
+ break;
+ case GDB_GS:
+ case GDB_FS:
+ *(unsigned long *)mem = 0xFFFF;
+ break;
+ }
+#endif
+ return dbg_reg_def[regno].name;
+}
+
+/**
+ * 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)
+{
+#ifndef CONFIG_X86_32
+ u32 *gdb_regs32 = (u32 *)gdb_regs;
+#endif
+ 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_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8);
+ gdb_regs32[GDB_CS] = __KERNEL_CS;
+ gdb_regs32[GDB_SS] = __KERNEL_DS;
+ 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;
+}
+
+static struct hw_breakpoint {
+ unsigned enabled;
+ unsigned long addr;
+ int len;
+ int type;
+ struct perf_event * __percpu *pev;
+} breakinfo[HBP_NUM];
+
+static unsigned long early_dr7;
+
+static void kgdb_correct_hw_break(void)
+{
+ int breakno;
+
+ for (breakno = 0; breakno < HBP_NUM; breakno++) {
+ struct perf_event *bp;
+ struct arch_hw_breakpoint *info;
+ int val;
+ int cpu = raw_smp_processor_id();
+ if (!breakinfo[breakno].enabled)
+ continue;
+ if (dbg_is_early) {
+ set_debugreg(breakinfo[breakno].addr, breakno);
+ early_dr7 |= encode_dr7(breakno,
+ breakinfo[breakno].len,
+ breakinfo[breakno].type);
+ set_debugreg(early_dr7, 7);
+ continue;
+ }
+ bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ info = counter_arch_bp(bp);
+ if (bp->attr.disabled != 1)
+ continue;
+ bp->attr.bp_addr = breakinfo[breakno].addr;
+ bp->attr.bp_len = breakinfo[breakno].len;
+ bp->attr.bp_type = breakinfo[breakno].type;
+ info->address = breakinfo[breakno].addr;
+ info->len = breakinfo[breakno].len;
+ info->type = breakinfo[breakno].type;
+ val = arch_install_hw_breakpoint(bp);
+ if (!val)
+ bp->attr.disabled = 0;
+ }
+ if (!dbg_is_early)
+ hw_breakpoint_restore();
+}
+
+static int hw_break_reserve_slot(int breakno)
+{
+ int cpu;
+ int cnt = 0;
+ struct perf_event **pevent;
+
+ if (dbg_is_early)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ cnt++;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_reserve_bp_slot(*pevent))
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ for_each_online_cpu(cpu) {
+ cnt--;
+ if (!cnt)
+ break;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ dbg_release_bp_slot(*pevent);
+ }
+ return -1;
+}
+
+static int hw_break_release_slot(int breakno)
+{
+ struct perf_event **pevent;
+ int cpu;
+
+ if (dbg_is_early)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_release_bp_slot(*pevent))
+ /*
+ * The debugger is responsible for handing the retry on
+ * remove failure.
+ */
+ return -1;
+ }
+ return 0;
+}
+
+static int
+kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ int i;
+
+ for (i = 0; i < HBP_NUM; i++)
+ if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+ break;
+ if (i == HBP_NUM)
+ return -1;
+
+ if (hw_break_release_slot(i)) {
+ printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
+ return -1;
+ }
+ breakinfo[i].enabled = 0;
+
+ return 0;
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
+ for (i = 0; i < HBP_NUM; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (!bp->attr.disabled) {
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ continue;
+ }
+ if (dbg_is_early)
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ else if (hw_break_release_slot(i))
+ printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n",
+ breakinfo[i].addr);
+ breakinfo[i].enabled = 0;
+ }
+}
+
+static int
+kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ int i;
+
+ for (i = 0; i < HBP_NUM; i++)
+ if (!breakinfo[i].enabled)
+ break;
+ if (i == HBP_NUM)
+ return -1;
+
+ switch (bptype) {
+ case BP_HARDWARE_BREAKPOINT:
+ len = 1;
+ breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
+ break;
+ case BP_WRITE_WATCHPOINT:
+ breakinfo[i].type = X86_BREAKPOINT_WRITE;
+ break;
+ case BP_ACCESS_WATCHPOINT:
+ breakinfo[i].type = X86_BREAKPOINT_RW;
+ break;
+ default:
+ return -1;
+ }
+ switch (len) {
+ case 1:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_1;
+ break;
+ case 2:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_2;
+ break;
+ case 4:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_4;
+ break;
+#ifdef CONFIG_X86_64
+ case 8:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_8;
+ break;
+#endif
+ default:
+ return -1;
+ }
+ breakinfo[i].addr = addr;
+ if (hw_break_reserve_slot(i)) {
+ breakinfo[i].addr = 0;
+ return -1;
+ }
+ breakinfo[i].enabled = 1;
+
+ 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.
+ */
+static void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
+ /* Disable hardware debugging while we are in kgdb: */
+ set_debugreg(0UL, 7);
+ for (i = 0; i < HBP_NUM; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ if (dbg_is_early) {
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ continue;
+ }
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled == 1)
+ continue;
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ }
+}
+
+#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)
+{
+ apic->send_IPI_allbutself(APIC_DM_NMI);
+}
+#endif
+
+/**
+ * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ * @e_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.
+ * @remcomInBuffer: The buffer of the packet we have read.
+ * @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into.
+ * @linux_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;
+ char *ptr;
+
+ 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':
+ /* 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;
+ atomic_set(&kgdb_cpu_doing_single_step,
+ raw_smp_processor_id());
+ }
+
+ 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);
+ /*
+ * Reset the BS bit in dr6 (pointed by args->err) to
+ * denote completion of processing
+ */
+ (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
+
+ return NOTIFY_STOP;
+}
+
+static DECLARE_BITMAP(was_in_debug_nmi, NR_CPUS);
+
+static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
+{
+ int cpu;
+
+ switch (cmd) {
+ case NMI_LOCAL:
+ if (atomic_read(&kgdb_active) != -1) {
+ /* KGDB CPU roundup */
+ cpu = raw_smp_processor_id();
+ kgdb_nmicallback(cpu, regs);
+ set_bit(cpu, was_in_debug_nmi);
+ touch_nmi_watchdog();
+
+ return NMI_HANDLED;
+ }
+ break;
+
+ case NMI_UNKNOWN:
+ cpu = raw_smp_processor_id();
+
+ if (__test_and_clear_bit(cpu, was_in_debug_nmi))
+ return NMI_HANDLED;
+
+ break;
+ default:
+ /* do nothing */
+ break;
+ }
+ return NMI_DONE;
+}
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+ struct pt_regs *regs = args->regs;
+
+ switch (cmd) {
+ case DIE_DEBUG:
+ if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
+ 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, cmd, regs))
+ return NOTIFY_DONE;
+
+ /* Must touch watchdog before return to normal operation */
+ touch_nmi_watchdog();
+ return NOTIFY_STOP;
+}
+
+int kgdb_ll_trap(int cmd, const char *str,
+ struct pt_regs *regs, long err, int trap, int sig)
+{
+ struct die_args args = {
+ .regs = regs,
+ .str = str,
+ .err = err,
+ .trapnr = trap,
+ .signr = sig,
+
+ };
+
+ if (!kgdb_io_module_registered)
+ return NOTIFY_DONE;
+
+ return __kgdb_notify(&args, cmd);
+}
+
+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,
+};
+
+/**
+ * kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ * This function will handle the initalization of any architecture
+ * specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+ int retval;
+
+ retval = register_die_notifier(&kgdb_notifier);
+ if (retval)
+ goto out;
+
+ retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler,
+ 0, "kgdb");
+ if (retval)
+ goto out1;
+
+ retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler,
+ 0, "kgdb");
+
+ if (retval)
+ goto out2;
+
+ return retval;
+
+out2:
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
+out1:
+ unregister_die_notifier(&kgdb_notifier);
+out:
+ return retval;
+}
+
+static void kgdb_hw_overflow_handler(struct perf_event *event,
+ struct perf_sample_data *data, struct pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+ int i;
+
+ for (i = 0; i < 4; i++)
+ if (breakinfo[i].enabled)
+ tsk->thread.debugreg6 |= (DR_TRAP0 << i);
+}
+
+void kgdb_arch_late(void)
+{
+ int i, cpu;
+ struct perf_event_attr attr;
+ struct perf_event **pevent;
+
+ /*
+ * Pre-allocate the hw breakpoint structions in the non-atomic
+ * portion of kgdb because this operation requires mutexs to
+ * complete.
+ */
+ hw_breakpoint_init(&attr);
+ attr.bp_addr = (unsigned long)kgdb_arch_init;
+ attr.bp_len = HW_BREAKPOINT_LEN_1;
+ attr.bp_type = HW_BREAKPOINT_W;
+ attr.disabled = 1;
+ for (i = 0; i < HBP_NUM; i++) {
+ if (breakinfo[i].pev)
+ continue;
+ breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
+ if (IS_ERR((void * __force)breakinfo[i].pev)) {
+ printk(KERN_ERR "kgdb: Could not allocate hw"
+ "breakpoints\nDisabling the kernel debugger\n");
+ breakinfo[i].pev = NULL;
+ kgdb_arch_exit();
+ return;
+ }
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
+ pevent[0]->hw.sample_period = 1;
+ pevent[0]->overflow_handler = kgdb_hw_overflow_handler;
+ if (pevent[0]->destroy != NULL) {
+ pevent[0]->destroy = NULL;
+ release_bp_slot(*pevent);
+ }
+ }
+ }
+}
+
+/**
+ * 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)
+{
+ int i;
+ for (i = 0; i < 4; i++) {
+ if (breakinfo[i].pev) {
+ unregister_wide_hw_breakpoint(breakinfo[i].pev);
+ breakinfo[i].pev = NULL;
+ }
+ }
+ unregister_nmi_handler(NMI_UNKNOWN, "kgdb");
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
+ 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);
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ regs->ip = ip;
+}
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+#ifdef CONFIG_DEBUG_RODATA
+ char opc[BREAK_INSTR_SIZE];
+#endif /* CONFIG_DEBUG_RODATA */
+
+ bpt->type = BP_BREAKPOINT;
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ err = probe_kernel_write((char *)bpt->bpt_addr,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+#ifdef CONFIG_DEBUG_RODATA
+ if (!err)
+ return err;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ return -EBUSY;
+ text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
+ return -EINVAL;
+ bpt->type = BP_POKE_BREAKPOINT;
+#endif /* CONFIG_DEBUG_RODATA */
+ return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+#ifdef CONFIG_DEBUG_RODATA
+ int err;
+ char opc[BREAK_INSTR_SIZE];
+
+ if (bpt->type != BP_POKE_BREAKPOINT)
+ goto knl_write;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ goto knl_write;
+ text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
+ goto knl_write;
+ return err;
+knl_write:
+#endif /* CONFIG_DEBUG_RODATA */
+ return probe_kernel_write((char *)bpt->bpt_addr,
+ (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
+}
+
+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,
+ .disable_hw_break = kgdb_disable_hw_debug,
+ .remove_all_hw_break = kgdb_remove_all_hw_break,
+ .correct_hw_break = kgdb_correct_hw_break,
+};