| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| */ |
| |
| /* |
| * 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/text-patching.h> |
| #include <asm/debugreg.h> |
| #include <asm/apicdef.h> |
| #include <asm/apic.h> |
| #include <asm/nmi.h> |
| #include <asm/switch_to.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_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] = ((struct inactive_task_frame *)p->thread.sp)->bp; |
| #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_SS] = __KERNEL_DS; |
| gdb_regs[GDB_FS] = 0xFFFF; |
| gdb_regs[GDB_GS] = 0xFFFF; |
| #else |
| gdb_regs32[GDB_PS] = 0; |
| gdb_regs32[GDB_CS] = __KERNEL_CS; |
| gdb_regs32[GDB_SS] = __KERNEL_DS; |
| 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_PC] = 0; |
| 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 |
| * |
| * 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. |
| * |
| * On non-SMP systems, this is not called. |
| */ |
| void kgdb_roundup_cpus(void) |
| { |
| apic_send_IPI_allbutself(NMI_VECTOR); |
| } |
| #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; |
| /* fall through */ |
| 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 initialization. |
| * |
| * This function will handle the initialization 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; |
| |
| bpt->type = BP_BREAKPOINT; |
| err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr, |
| BREAK_INSTR_SIZE); |
| if (err) |
| return err; |
| err = copy_to_kernel_nofault((char *)bpt->bpt_addr, |
| arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); |
| if (!err) |
| return err; |
| /* |
| * It is safe to call text_poke_kgdb() 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_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, |
| BREAK_INSTR_SIZE); |
| bpt->type = BP_POKE_BREAKPOINT; |
| |
| return 0; |
| } |
| |
| int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
| { |
| if (bpt->type != BP_POKE_BREAKPOINT) |
| goto knl_write; |
| /* |
| * It is safe to call text_poke_kgdb() 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_kgdb((void *)bpt->bpt_addr, bpt->saved_instr, |
| BREAK_INSTR_SIZE); |
| return 0; |
| |
| knl_write: |
| return copy_to_kernel_nofault((char *)bpt->bpt_addr, |
| (char *)bpt->saved_instr, BREAK_INSTR_SIZE); |
| } |
| |
| const 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, |
| }; |