2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License as published by the
4 * Free Software Foundation; either version 2, or (at your option) any
7 * This program is distributed in the hope that it will be useful, but
8 * WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
15 * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
16 * Copyright (C) 2000-2001 VERITAS Software Corporation.
17 * Copyright (C) 2002 Andi Kleen, SuSE Labs
18 * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
19 * Copyright (C) 2007 MontaVista Software, Inc.
20 * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
22 /****************************************************************************
23 * Contributor: Lake Stevens Instrument Division$
24 * Written by: Glenn Engel $
25 * Updated by: Amit Kale<akale@veritas.com>
26 * Updated by: Tom Rini <trini@kernel.crashing.org>
27 * Updated by: Jason Wessel <jason.wessel@windriver.com>
28 * Modified for 386 by Jim Kingdon, Cygnus Support.
29 * Origianl kgdb, compatibility with 2.1.xx kernel by
30 * David Grothe <dave@gcom.com>
31 * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
32 * X86_64 changes from Andi Kleen's patch merged by Jim Houston
34 #include <linux/spinlock.h>
35 #include <linux/kdebug.h>
36 #include <linux/string.h>
37 #include <linux/kernel.h>
38 #include <linux/ptrace.h>
39 #include <linux/sched.h>
40 #include <linux/delay.h>
41 #include <linux/kgdb.h>
42 #include <linux/init.h>
43 #include <linux/smp.h>
44 #include <linux/nmi.h>
45 #include <linux/hw_breakpoint.h>
47 #include <asm/debugreg.h>
48 #include <asm/apicdef.h>
49 #include <asm/system.h>
53 struct dbg_reg_def_t dbg_reg_def
[DBG_MAX_REG_NUM
] =
56 { "ax", 4, offsetof(struct pt_regs
, ax
) },
57 { "cx", 4, offsetof(struct pt_regs
, cx
) },
58 { "dx", 4, offsetof(struct pt_regs
, dx
) },
59 { "bx", 4, offsetof(struct pt_regs
, bx
) },
60 { "sp", 4, offsetof(struct pt_regs
, sp
) },
61 { "bp", 4, offsetof(struct pt_regs
, bp
) },
62 { "si", 4, offsetof(struct pt_regs
, si
) },
63 { "di", 4, offsetof(struct pt_regs
, di
) },
64 { "ip", 4, offsetof(struct pt_regs
, ip
) },
65 { "flags", 4, offsetof(struct pt_regs
, flags
) },
66 { "cs", 4, offsetof(struct pt_regs
, cs
) },
67 { "ss", 4, offsetof(struct pt_regs
, ss
) },
68 { "ds", 4, offsetof(struct pt_regs
, ds
) },
69 { "es", 4, offsetof(struct pt_regs
, es
) },
73 { "ax", 8, offsetof(struct pt_regs
, ax
) },
74 { "bx", 8, offsetof(struct pt_regs
, bx
) },
75 { "cx", 8, offsetof(struct pt_regs
, cx
) },
76 { "dx", 8, offsetof(struct pt_regs
, dx
) },
77 { "si", 8, offsetof(struct pt_regs
, dx
) },
78 { "di", 8, offsetof(struct pt_regs
, di
) },
79 { "bp", 8, offsetof(struct pt_regs
, bp
) },
80 { "sp", 8, offsetof(struct pt_regs
, sp
) },
81 { "r8", 8, offsetof(struct pt_regs
, r8
) },
82 { "r9", 8, offsetof(struct pt_regs
, r9
) },
83 { "r10", 8, offsetof(struct pt_regs
, r10
) },
84 { "r11", 8, offsetof(struct pt_regs
, r11
) },
85 { "r12", 8, offsetof(struct pt_regs
, r12
) },
86 { "r13", 8, offsetof(struct pt_regs
, r13
) },
87 { "r14", 8, offsetof(struct pt_regs
, r14
) },
88 { "r15", 8, offsetof(struct pt_regs
, r15
) },
89 { "ip", 8, offsetof(struct pt_regs
, ip
) },
90 { "flags", 4, offsetof(struct pt_regs
, flags
) },
91 { "cs", 4, offsetof(struct pt_regs
, cs
) },
92 { "ss", 4, offsetof(struct pt_regs
, ss
) },
96 int dbg_set_reg(int regno
, void *mem
, struct pt_regs
*regs
)
100 regno
== GDB_SS
|| regno
== GDB_FS
|| regno
== GDB_GS
||
102 regno
== GDB_SP
|| regno
== GDB_ORIG_AX
)
105 if (dbg_reg_def
[regno
].offset
!= -1)
106 memcpy((void *)regs
+ dbg_reg_def
[regno
].offset
, mem
,
107 dbg_reg_def
[regno
].size
);
111 char *dbg_get_reg(int regno
, void *mem
, struct pt_regs
*regs
)
113 if (regno
== GDB_ORIG_AX
) {
114 memcpy(mem
, ®s
->orig_ax
, sizeof(regs
->orig_ax
));
117 if (regno
>= DBG_MAX_REG_NUM
|| regno
< 0)
120 if (dbg_reg_def
[regno
].offset
!= -1)
121 memcpy(mem
, (void *)regs
+ dbg_reg_def
[regno
].offset
,
122 dbg_reg_def
[regno
].size
);
127 if (!user_mode_vm(regs
))
128 *(unsigned long *)mem
= __KERNEL_DS
;
131 if (!user_mode_vm(regs
))
132 *(unsigned long *)mem
= kernel_stack_pointer(regs
);
136 *(unsigned long *)mem
= 0xFFFF;
140 return dbg_reg_def
[regno
].name
;
144 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
145 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
146 * @p: The &struct task_struct of the desired process.
148 * Convert the register values of the sleeping process in @p to
149 * the format that GDB expects.
150 * This function is called when kgdb does not have access to the
151 * &struct pt_regs and therefore it should fill the gdb registers
152 * @gdb_regs with what has been saved in &struct thread_struct
153 * thread field during switch_to.
155 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs
, struct task_struct
*p
)
157 #ifndef CONFIG_X86_32
158 u32
*gdb_regs32
= (u32
*)gdb_regs
;
160 gdb_regs
[GDB_AX
] = 0;
161 gdb_regs
[GDB_BX
] = 0;
162 gdb_regs
[GDB_CX
] = 0;
163 gdb_regs
[GDB_DX
] = 0;
164 gdb_regs
[GDB_SI
] = 0;
165 gdb_regs
[GDB_DI
] = 0;
166 gdb_regs
[GDB_BP
] = *(unsigned long *)p
->thread
.sp
;
168 gdb_regs
[GDB_DS
] = __KERNEL_DS
;
169 gdb_regs
[GDB_ES
] = __KERNEL_DS
;
170 gdb_regs
[GDB_PS
] = 0;
171 gdb_regs
[GDB_CS
] = __KERNEL_CS
;
172 gdb_regs
[GDB_PC
] = p
->thread
.ip
;
173 gdb_regs
[GDB_SS
] = __KERNEL_DS
;
174 gdb_regs
[GDB_FS
] = 0xFFFF;
175 gdb_regs
[GDB_GS
] = 0xFFFF;
177 gdb_regs32
[GDB_PS
] = *(unsigned long *)(p
->thread
.sp
+ 8);
178 gdb_regs32
[GDB_CS
] = __KERNEL_CS
;
179 gdb_regs32
[GDB_SS
] = __KERNEL_DS
;
180 gdb_regs
[GDB_PC
] = 0;
181 gdb_regs
[GDB_R8
] = 0;
182 gdb_regs
[GDB_R9
] = 0;
183 gdb_regs
[GDB_R10
] = 0;
184 gdb_regs
[GDB_R11
] = 0;
185 gdb_regs
[GDB_R12
] = 0;
186 gdb_regs
[GDB_R13
] = 0;
187 gdb_regs
[GDB_R14
] = 0;
188 gdb_regs
[GDB_R15
] = 0;
190 gdb_regs
[GDB_SP
] = p
->thread
.sp
;
193 static struct hw_breakpoint
{
198 struct perf_event
* __percpu
*pev
;
199 } breakinfo
[HBP_NUM
];
201 static unsigned long early_dr7
;
203 static void kgdb_correct_hw_break(void)
207 for (breakno
= 0; breakno
< HBP_NUM
; breakno
++) {
208 struct perf_event
*bp
;
209 struct arch_hw_breakpoint
*info
;
211 int cpu
= raw_smp_processor_id();
212 if (!breakinfo
[breakno
].enabled
)
215 set_debugreg(breakinfo
[breakno
].addr
, breakno
);
216 early_dr7
|= encode_dr7(breakno
,
217 breakinfo
[breakno
].len
,
218 breakinfo
[breakno
].type
);
219 set_debugreg(early_dr7
, 7);
222 bp
= *per_cpu_ptr(breakinfo
[breakno
].pev
, cpu
);
223 info
= counter_arch_bp(bp
);
224 if (bp
->attr
.disabled
!= 1)
226 bp
->attr
.bp_addr
= breakinfo
[breakno
].addr
;
227 bp
->attr
.bp_len
= breakinfo
[breakno
].len
;
228 bp
->attr
.bp_type
= breakinfo
[breakno
].type
;
229 info
->address
= breakinfo
[breakno
].addr
;
230 info
->len
= breakinfo
[breakno
].len
;
231 info
->type
= breakinfo
[breakno
].type
;
232 val
= arch_install_hw_breakpoint(bp
);
234 bp
->attr
.disabled
= 0;
237 hw_breakpoint_restore();
240 static int hw_break_reserve_slot(int breakno
)
244 struct perf_event
**pevent
;
249 for_each_online_cpu(cpu
) {
251 pevent
= per_cpu_ptr(breakinfo
[breakno
].pev
, cpu
);
252 if (dbg_reserve_bp_slot(*pevent
))
259 for_each_online_cpu(cpu
) {
263 pevent
= per_cpu_ptr(breakinfo
[breakno
].pev
, cpu
);
264 dbg_release_bp_slot(*pevent
);
269 static int hw_break_release_slot(int breakno
)
271 struct perf_event
**pevent
;
277 for_each_online_cpu(cpu
) {
278 pevent
= per_cpu_ptr(breakinfo
[breakno
].pev
, cpu
);
279 if (dbg_release_bp_slot(*pevent
))
281 * The debugger is responsible for handing the retry on
290 kgdb_remove_hw_break(unsigned long addr
, int len
, enum kgdb_bptype bptype
)
294 for (i
= 0; i
< HBP_NUM
; i
++)
295 if (breakinfo
[i
].addr
== addr
&& breakinfo
[i
].enabled
)
300 if (hw_break_release_slot(i
)) {
301 printk(KERN_ERR
"Cannot remove hw breakpoint at %lx\n", addr
);
304 breakinfo
[i
].enabled
= 0;
309 static void kgdb_remove_all_hw_break(void)
312 int cpu
= raw_smp_processor_id();
313 struct perf_event
*bp
;
315 for (i
= 0; i
< HBP_NUM
; i
++) {
316 if (!breakinfo
[i
].enabled
)
318 bp
= *per_cpu_ptr(breakinfo
[i
].pev
, cpu
);
319 if (!bp
->attr
.disabled
) {
320 arch_uninstall_hw_breakpoint(bp
);
321 bp
->attr
.disabled
= 1;
325 early_dr7
&= ~encode_dr7(i
, breakinfo
[i
].len
,
327 else if (hw_break_release_slot(i
))
328 printk(KERN_ERR
"KGDB: hw bpt remove failed %lx\n",
330 breakinfo
[i
].enabled
= 0;
335 kgdb_set_hw_break(unsigned long addr
, int len
, enum kgdb_bptype bptype
)
339 for (i
= 0; i
< HBP_NUM
; i
++)
340 if (!breakinfo
[i
].enabled
)
346 case BP_HARDWARE_BREAKPOINT
:
348 breakinfo
[i
].type
= X86_BREAKPOINT_EXECUTE
;
350 case BP_WRITE_WATCHPOINT
:
351 breakinfo
[i
].type
= X86_BREAKPOINT_WRITE
;
353 case BP_ACCESS_WATCHPOINT
:
354 breakinfo
[i
].type
= X86_BREAKPOINT_RW
;
361 breakinfo
[i
].len
= X86_BREAKPOINT_LEN_1
;
364 breakinfo
[i
].len
= X86_BREAKPOINT_LEN_2
;
367 breakinfo
[i
].len
= X86_BREAKPOINT_LEN_4
;
371 breakinfo
[i
].len
= X86_BREAKPOINT_LEN_8
;
377 breakinfo
[i
].addr
= addr
;
378 if (hw_break_reserve_slot(i
)) {
379 breakinfo
[i
].addr
= 0;
382 breakinfo
[i
].enabled
= 1;
388 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
389 * @regs: Current &struct pt_regs.
391 * This function will be called if the particular architecture must
392 * disable hardware debugging while it is processing gdb packets or
393 * handling exception.
395 static void kgdb_disable_hw_debug(struct pt_regs
*regs
)
398 int cpu
= raw_smp_processor_id();
399 struct perf_event
*bp
;
401 /* Disable hardware debugging while we are in kgdb: */
402 set_debugreg(0UL, 7);
403 for (i
= 0; i
< HBP_NUM
; i
++) {
404 if (!breakinfo
[i
].enabled
)
407 early_dr7
&= ~encode_dr7(i
, breakinfo
[i
].len
,
411 bp
= *per_cpu_ptr(breakinfo
[i
].pev
, cpu
);
412 if (bp
->attr
.disabled
== 1)
414 arch_uninstall_hw_breakpoint(bp
);
415 bp
->attr
.disabled
= 1;
421 * kgdb_roundup_cpus - Get other CPUs into a holding pattern
422 * @flags: Current IRQ state
424 * On SMP systems, we need to get the attention of the other CPUs
425 * and get them be in a known state. This should do what is needed
426 * to get the other CPUs to call kgdb_wait(). Note that on some arches,
427 * the NMI approach is not used for rounding up all the CPUs. For example,
428 * in case of MIPS, smp_call_function() is used to roundup CPUs. In
429 * this case, we have to make sure that interrupts are enabled before
430 * calling smp_call_function(). The argument to this function is
431 * the flags that will be used when restoring the interrupts. There is
432 * local_irq_save() call before kgdb_roundup_cpus().
434 * On non-SMP systems, this is not called.
436 void kgdb_roundup_cpus(unsigned long flags
)
438 apic
->send_IPI_allbutself(APIC_DM_NMI
);
443 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
444 * @vector: The error vector of the exception that happened.
445 * @signo: The signal number of the exception that happened.
446 * @err_code: The error code of the exception that happened.
447 * @remcom_in_buffer: The buffer of the packet we have read.
448 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
449 * @regs: The &struct pt_regs of the current process.
451 * This function MUST handle the 'c' and 's' command packets,
452 * as well packets to set / remove a hardware breakpoint, if used.
453 * If there are additional packets which the hardware needs to handle,
454 * they are handled here. The code should return -1 if it wants to
455 * process more packets, and a %0 or %1 if it wants to exit from the
458 int kgdb_arch_handle_exception(int e_vector
, int signo
, int err_code
,
459 char *remcomInBuffer
, char *remcomOutBuffer
,
460 struct pt_regs
*linux_regs
)
465 switch (remcomInBuffer
[0]) {
468 /* try to read optional parameter, pc unchanged if no parm */
469 ptr
= &remcomInBuffer
[1];
470 if (kgdb_hex2long(&ptr
, &addr
))
471 linux_regs
->ip
= addr
;
474 /* clear the trace bit */
475 linux_regs
->flags
&= ~X86_EFLAGS_TF
;
476 atomic_set(&kgdb_cpu_doing_single_step
, -1);
478 /* set the trace bit if we're stepping */
479 if (remcomInBuffer
[0] == 's') {
480 linux_regs
->flags
|= X86_EFLAGS_TF
;
481 atomic_set(&kgdb_cpu_doing_single_step
,
482 raw_smp_processor_id());
488 /* this means that we do not want to exit from the handler: */
493 single_step_cont(struct pt_regs
*regs
, struct die_args
*args
)
496 * Single step exception from kernel space to user space so
497 * eat the exception and continue the process:
499 printk(KERN_ERR
"KGDB: trap/step from kernel to user space, "
501 kgdb_arch_handle_exception(args
->trapnr
, args
->signr
,
502 args
->err
, "c", "", regs
);
504 * Reset the BS bit in dr6 (pointed by args->err) to
505 * denote completion of processing
507 (*(unsigned long *)ERR_PTR(args
->err
)) &= ~DR_STEP
;
512 static int was_in_debug_nmi
[NR_CPUS
];
514 static int __kgdb_notify(struct die_args
*args
, unsigned long cmd
)
516 struct pt_regs
*regs
= args
->regs
;
520 if (atomic_read(&kgdb_active
) != -1) {
521 /* KGDB CPU roundup */
522 kgdb_nmicallback(raw_smp_processor_id(), regs
);
523 was_in_debug_nmi
[raw_smp_processor_id()] = 1;
524 touch_nmi_watchdog();
530 if (was_in_debug_nmi
[raw_smp_processor_id()]) {
531 was_in_debug_nmi
[raw_smp_processor_id()] = 0;
537 if (atomic_read(&kgdb_cpu_doing_single_step
) != -1) {
539 return single_step_cont(regs
, args
);
541 } else if (test_thread_flag(TIF_SINGLESTEP
))
542 /* This means a user thread is single stepping
543 * a system call which should be ignored
552 if (kgdb_handle_exception(args
->trapnr
, args
->signr
, cmd
, regs
))
555 /* Must touch watchdog before return to normal operation */
556 touch_nmi_watchdog();
560 int kgdb_ll_trap(int cmd
, const char *str
,
561 struct pt_regs
*regs
, long err
, int trap
, int sig
)
563 struct die_args args
= {
572 if (!kgdb_io_module_registered
)
575 return __kgdb_notify(&args
, cmd
);
579 kgdb_notify(struct notifier_block
*self
, unsigned long cmd
, void *ptr
)
584 local_irq_save(flags
);
585 ret
= __kgdb_notify(ptr
, cmd
);
586 local_irq_restore(flags
);
591 static struct notifier_block kgdb_notifier
= {
592 .notifier_call
= kgdb_notify
,
595 * Lowest-prio notifier priority, we want to be notified last:
597 .priority
= NMI_LOCAL_LOW_PRIOR
,
601 * kgdb_arch_init - Perform any architecture specific initalization.
603 * This function will handle the initalization of any architecture
604 * specific callbacks.
606 int kgdb_arch_init(void)
608 return register_die_notifier(&kgdb_notifier
);
611 static void kgdb_hw_overflow_handler(struct perf_event
*event
,
612 struct perf_sample_data
*data
, struct pt_regs
*regs
)
614 struct task_struct
*tsk
= current
;
617 for (i
= 0; i
< 4; i
++)
618 if (breakinfo
[i
].enabled
)
619 tsk
->thread
.debugreg6
|= (DR_TRAP0
<< i
);
622 void kgdb_arch_late(void)
625 struct perf_event_attr attr
;
626 struct perf_event
**pevent
;
629 * Pre-allocate the hw breakpoint structions in the non-atomic
630 * portion of kgdb because this operation requires mutexs to
633 hw_breakpoint_init(&attr
);
634 attr
.bp_addr
= (unsigned long)kgdb_arch_init
;
635 attr
.bp_len
= HW_BREAKPOINT_LEN_1
;
636 attr
.bp_type
= HW_BREAKPOINT_W
;
638 for (i
= 0; i
< HBP_NUM
; i
++) {
639 if (breakinfo
[i
].pev
)
641 breakinfo
[i
].pev
= register_wide_hw_breakpoint(&attr
, NULL
, NULL
);
642 if (IS_ERR((void * __force
)breakinfo
[i
].pev
)) {
643 printk(KERN_ERR
"kgdb: Could not allocate hw"
644 "breakpoints\nDisabling the kernel debugger\n");
645 breakinfo
[i
].pev
= NULL
;
649 for_each_online_cpu(cpu
) {
650 pevent
= per_cpu_ptr(breakinfo
[i
].pev
, cpu
);
651 pevent
[0]->hw
.sample_period
= 1;
652 pevent
[0]->overflow_handler
= kgdb_hw_overflow_handler
;
653 if (pevent
[0]->destroy
!= NULL
) {
654 pevent
[0]->destroy
= NULL
;
655 release_bp_slot(*pevent
);
662 * kgdb_arch_exit - Perform any architecture specific uninitalization.
664 * This function will handle the uninitalization of any architecture
665 * specific callbacks, for dynamic registration and unregistration.
667 void kgdb_arch_exit(void)
670 for (i
= 0; i
< 4; i
++) {
671 if (breakinfo
[i
].pev
) {
672 unregister_wide_hw_breakpoint(breakinfo
[i
].pev
);
673 breakinfo
[i
].pev
= NULL
;
676 unregister_die_notifier(&kgdb_notifier
);
681 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
682 * @exception: Exception vector number
683 * @regs: Current &struct pt_regs.
685 * On some architectures we need to skip a breakpoint exception when
686 * it occurs after a breakpoint has been removed.
688 * Skip an int3 exception when it occurs after a breakpoint has been
689 * removed. Backtrack eip by 1 since the int3 would have caused it to
692 int kgdb_skipexception(int exception
, struct pt_regs
*regs
)
694 if (exception
== 3 && kgdb_isremovedbreak(regs
->ip
- 1)) {
701 unsigned long kgdb_arch_pc(int exception
, struct pt_regs
*regs
)
704 return instruction_pointer(regs
) - 1;
705 return instruction_pointer(regs
);
708 void kgdb_arch_set_pc(struct pt_regs
*regs
, unsigned long ip
)
713 struct kgdb_arch arch_kgdb_ops
= {
714 /* Breakpoint instruction: */
715 .gdb_bpt_instr
= { 0xcc },
716 .flags
= KGDB_HW_BREAKPOINT
,
717 .set_hw_breakpoint
= kgdb_set_hw_break
,
718 .remove_hw_breakpoint
= kgdb_remove_hw_break
,
719 .disable_hw_break
= kgdb_disable_hw_debug
,
720 .remove_all_hw_break
= kgdb_remove_all_hw_break
,
721 .correct_hw_break
= kgdb_correct_hw_break
,