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>
46 #include <asm/debugreg.h>
47 #include <asm/apicdef.h>
48 #include <asm/system.h>
53 * Put the error code here just in case the user cares:
55 static int gdb_x86errcode
;
58 * Likewise, the vector number here (since GDB only gets the signal
59 * number through the usual means, and that's not very specific):
61 static int gdb_x86vector
= -1;
64 * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
65 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
66 * @regs: The &struct pt_regs of the current process.
68 * Convert the pt_regs in @regs into the format for registers that
69 * GDB expects, stored in @gdb_regs.
71 void pt_regs_to_gdb_regs(unsigned long *gdb_regs
, struct pt_regs
*regs
)
74 u32
*gdb_regs32
= (u32
*)gdb_regs
;
76 gdb_regs
[GDB_AX
] = regs
->ax
;
77 gdb_regs
[GDB_BX
] = regs
->bx
;
78 gdb_regs
[GDB_CX
] = regs
->cx
;
79 gdb_regs
[GDB_DX
] = regs
->dx
;
80 gdb_regs
[GDB_SI
] = regs
->si
;
81 gdb_regs
[GDB_DI
] = regs
->di
;
82 gdb_regs
[GDB_BP
] = regs
->bp
;
83 gdb_regs
[GDB_PC
] = regs
->ip
;
85 gdb_regs
[GDB_PS
] = regs
->flags
;
86 gdb_regs
[GDB_DS
] = regs
->ds
;
87 gdb_regs
[GDB_ES
] = regs
->es
;
88 gdb_regs
[GDB_CS
] = regs
->cs
;
89 gdb_regs
[GDB_SS
] = __KERNEL_DS
;
90 gdb_regs
[GDB_FS
] = 0xFFFF;
91 gdb_regs
[GDB_GS
] = 0xFFFF;
92 gdb_regs
[GDB_SP
] = (int)®s
->sp
;
94 gdb_regs
[GDB_R8
] = regs
->r8
;
95 gdb_regs
[GDB_R9
] = regs
->r9
;
96 gdb_regs
[GDB_R10
] = regs
->r10
;
97 gdb_regs
[GDB_R11
] = regs
->r11
;
98 gdb_regs
[GDB_R12
] = regs
->r12
;
99 gdb_regs
[GDB_R13
] = regs
->r13
;
100 gdb_regs
[GDB_R14
] = regs
->r14
;
101 gdb_regs
[GDB_R15
] = regs
->r15
;
102 gdb_regs32
[GDB_PS
] = regs
->flags
;
103 gdb_regs32
[GDB_CS
] = regs
->cs
;
104 gdb_regs32
[GDB_SS
] = regs
->ss
;
105 gdb_regs
[GDB_SP
] = regs
->sp
;
110 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
111 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
112 * @p: The &struct task_struct of the desired process.
114 * Convert the register values of the sleeping process in @p to
115 * the format that GDB expects.
116 * This function is called when kgdb does not have access to the
117 * &struct pt_regs and therefore it should fill the gdb registers
118 * @gdb_regs with what has been saved in &struct thread_struct
119 * thread field during switch_to.
121 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs
, struct task_struct
*p
)
123 #ifndef CONFIG_X86_32
124 u32
*gdb_regs32
= (u32
*)gdb_regs
;
126 gdb_regs
[GDB_AX
] = 0;
127 gdb_regs
[GDB_BX
] = 0;
128 gdb_regs
[GDB_CX
] = 0;
129 gdb_regs
[GDB_DX
] = 0;
130 gdb_regs
[GDB_SI
] = 0;
131 gdb_regs
[GDB_DI
] = 0;
132 gdb_regs
[GDB_BP
] = *(unsigned long *)p
->thread
.sp
;
134 gdb_regs
[GDB_DS
] = __KERNEL_DS
;
135 gdb_regs
[GDB_ES
] = __KERNEL_DS
;
136 gdb_regs
[GDB_PS
] = 0;
137 gdb_regs
[GDB_CS
] = __KERNEL_CS
;
138 gdb_regs
[GDB_PC
] = p
->thread
.ip
;
139 gdb_regs
[GDB_SS
] = __KERNEL_DS
;
140 gdb_regs
[GDB_FS
] = 0xFFFF;
141 gdb_regs
[GDB_GS
] = 0xFFFF;
143 gdb_regs32
[GDB_PS
] = *(unsigned long *)(p
->thread
.sp
+ 8);
144 gdb_regs32
[GDB_CS
] = __KERNEL_CS
;
145 gdb_regs32
[GDB_SS
] = __KERNEL_DS
;
146 gdb_regs
[GDB_PC
] = p
->thread
.ip
;
147 gdb_regs
[GDB_R8
] = 0;
148 gdb_regs
[GDB_R9
] = 0;
149 gdb_regs
[GDB_R10
] = 0;
150 gdb_regs
[GDB_R11
] = 0;
151 gdb_regs
[GDB_R12
] = 0;
152 gdb_regs
[GDB_R13
] = 0;
153 gdb_regs
[GDB_R14
] = 0;
154 gdb_regs
[GDB_R15
] = 0;
156 gdb_regs
[GDB_SP
] = p
->thread
.sp
;
160 * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
161 * @gdb_regs: A pointer to hold the registers we've received from GDB.
162 * @regs: A pointer to a &struct pt_regs to hold these values in.
164 * Convert the GDB regs in @gdb_regs into the pt_regs, and store them
167 void gdb_regs_to_pt_regs(unsigned long *gdb_regs
, struct pt_regs
*regs
)
169 #ifndef CONFIG_X86_32
170 u32
*gdb_regs32
= (u32
*)gdb_regs
;
172 regs
->ax
= gdb_regs
[GDB_AX
];
173 regs
->bx
= gdb_regs
[GDB_BX
];
174 regs
->cx
= gdb_regs
[GDB_CX
];
175 regs
->dx
= gdb_regs
[GDB_DX
];
176 regs
->si
= gdb_regs
[GDB_SI
];
177 regs
->di
= gdb_regs
[GDB_DI
];
178 regs
->bp
= gdb_regs
[GDB_BP
];
179 regs
->ip
= gdb_regs
[GDB_PC
];
181 regs
->flags
= gdb_regs
[GDB_PS
];
182 regs
->ds
= gdb_regs
[GDB_DS
];
183 regs
->es
= gdb_regs
[GDB_ES
];
184 regs
->cs
= gdb_regs
[GDB_CS
];
186 regs
->r8
= gdb_regs
[GDB_R8
];
187 regs
->r9
= gdb_regs
[GDB_R9
];
188 regs
->r10
= gdb_regs
[GDB_R10
];
189 regs
->r11
= gdb_regs
[GDB_R11
];
190 regs
->r12
= gdb_regs
[GDB_R12
];
191 regs
->r13
= gdb_regs
[GDB_R13
];
192 regs
->r14
= gdb_regs
[GDB_R14
];
193 regs
->r15
= gdb_regs
[GDB_R15
];
194 regs
->flags
= gdb_regs32
[GDB_PS
];
195 regs
->cs
= gdb_regs32
[GDB_CS
];
196 regs
->ss
= gdb_regs32
[GDB_SS
];
200 static struct hw_breakpoint
{
207 static void kgdb_correct_hw_break(void)
214 get_debugreg(dr7
, 7);
215 for (breakno
= 0; breakno
< 4; breakno
++) {
216 breakbit
= 2 << (breakno
<< 1);
217 if (!(dr7
& breakbit
) && breakinfo
[breakno
].enabled
) {
220 dr7
&= ~(0xf0000 << (breakno
<< 2));
221 dr7
|= ((breakinfo
[breakno
].len
<< 2) |
222 breakinfo
[breakno
].type
) <<
223 ((breakno
<< 2) + 16);
224 if (breakno
>= 0 && breakno
<= 3)
225 set_debugreg(breakinfo
[breakno
].addr
, breakno
);
228 if ((dr7
& breakbit
) && !breakinfo
[breakno
].enabled
) {
231 dr7
&= ~(0xf0000 << (breakno
<< 2));
236 set_debugreg(dr7
, 7);
240 kgdb_remove_hw_break(unsigned long addr
, int len
, enum kgdb_bptype bptype
)
244 for (i
= 0; i
< 4; i
++)
245 if (breakinfo
[i
].addr
== addr
&& breakinfo
[i
].enabled
)
250 breakinfo
[i
].enabled
= 0;
255 static void kgdb_remove_all_hw_break(void)
259 for (i
= 0; i
< 4; i
++)
260 memset(&breakinfo
[i
], 0, sizeof(struct hw_breakpoint
));
264 kgdb_set_hw_break(unsigned long addr
, int len
, enum kgdb_bptype bptype
)
269 for (i
= 0; i
< 4; i
++)
270 if (!breakinfo
[i
].enabled
)
276 case BP_HARDWARE_BREAKPOINT
:
280 case BP_WRITE_WATCHPOINT
:
283 case BP_ACCESS_WATCHPOINT
:
290 if (len
== 1 || len
== 2 || len
== 4)
291 breakinfo
[i
].len
= len
- 1;
295 breakinfo
[i
].enabled
= 1;
296 breakinfo
[i
].addr
= addr
;
297 breakinfo
[i
].type
= type
;
303 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
304 * @regs: Current &struct pt_regs.
306 * This function will be called if the particular architecture must
307 * disable hardware debugging while it is processing gdb packets or
308 * handling exception.
310 void kgdb_disable_hw_debug(struct pt_regs
*regs
)
312 /* Disable hardware debugging while we are in kgdb: */
313 set_debugreg(0UL, 7);
317 * kgdb_post_primary_code - Save error vector/code numbers.
318 * @regs: Original pt_regs.
319 * @e_vector: Original error vector.
320 * @err_code: Original error code.
322 * This is needed on architectures which support SMP and KGDB.
323 * This function is called after all the slave cpus have been put
324 * to a know spin state and the primary CPU has control over KGDB.
326 void kgdb_post_primary_code(struct pt_regs
*regs
, int e_vector
, int err_code
)
328 /* primary processor is completely in the debugger */
329 gdb_x86vector
= e_vector
;
330 gdb_x86errcode
= err_code
;
335 * kgdb_roundup_cpus - Get other CPUs into a holding pattern
336 * @flags: Current IRQ state
338 * On SMP systems, we need to get the attention of the other CPUs
339 * and get them be in a known state. This should do what is needed
340 * to get the other CPUs to call kgdb_wait(). Note that on some arches,
341 * the NMI approach is not used for rounding up all the CPUs. For example,
342 * in case of MIPS, smp_call_function() is used to roundup CPUs. In
343 * this case, we have to make sure that interrupts are enabled before
344 * calling smp_call_function(). The argument to this function is
345 * the flags that will be used when restoring the interrupts. There is
346 * local_irq_save() call before kgdb_roundup_cpus().
348 * On non-SMP systems, this is not called.
350 void kgdb_roundup_cpus(unsigned long flags
)
352 apic
->send_IPI_allbutself(APIC_DM_NMI
);
357 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
358 * @vector: The error vector of the exception that happened.
359 * @signo: The signal number of the exception that happened.
360 * @err_code: The error code of the exception that happened.
361 * @remcom_in_buffer: The buffer of the packet we have read.
362 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
363 * @regs: The &struct pt_regs of the current process.
365 * This function MUST handle the 'c' and 's' command packets,
366 * as well packets to set / remove a hardware breakpoint, if used.
367 * If there are additional packets which the hardware needs to handle,
368 * they are handled here. The code should return -1 if it wants to
369 * process more packets, and a %0 or %1 if it wants to exit from the
372 int kgdb_arch_handle_exception(int e_vector
, int signo
, int err_code
,
373 char *remcomInBuffer
, char *remcomOutBuffer
,
374 struct pt_regs
*linux_regs
)
381 switch (remcomInBuffer
[0]) {
384 /* try to read optional parameter, pc unchanged if no parm */
385 ptr
= &remcomInBuffer
[1];
386 if (kgdb_hex2long(&ptr
, &addr
))
387 linux_regs
->ip
= addr
;
390 newPC
= linux_regs
->ip
;
392 /* clear the trace bit */
393 linux_regs
->flags
&= ~X86_EFLAGS_TF
;
394 atomic_set(&kgdb_cpu_doing_single_step
, -1);
396 /* set the trace bit if we're stepping */
397 if (remcomInBuffer
[0] == 's') {
398 linux_regs
->flags
|= X86_EFLAGS_TF
;
399 kgdb_single_step
= 1;
400 atomic_set(&kgdb_cpu_doing_single_step
,
401 raw_smp_processor_id());
404 get_debugreg(dr6
, 6);
405 if (!(dr6
& 0x4000)) {
408 for (breakno
= 0; breakno
< 4; breakno
++) {
409 if (dr6
& (1 << breakno
) &&
410 breakinfo
[breakno
].type
== 0) {
411 /* Set restore flag: */
412 linux_regs
->flags
|= X86_EFLAGS_RF
;
417 set_debugreg(0UL, 6);
418 kgdb_correct_hw_break();
423 /* this means that we do not want to exit from the handler: */
428 single_step_cont(struct pt_regs
*regs
, struct die_args
*args
)
431 * Single step exception from kernel space to user space so
432 * eat the exception and continue the process:
434 printk(KERN_ERR
"KGDB: trap/step from kernel to user space, "
436 kgdb_arch_handle_exception(args
->trapnr
, args
->signr
,
437 args
->err
, "c", "", regs
);
439 * Reset the BS bit in dr6 (pointed by args->err) to
440 * denote completion of processing
442 (*(unsigned long *)ERR_PTR(args
->err
)) &= ~DR_STEP
;
447 static int was_in_debug_nmi
[NR_CPUS
];
449 static int __kgdb_notify(struct die_args
*args
, unsigned long cmd
)
451 struct pt_regs
*regs
= args
->regs
;
455 if (atomic_read(&kgdb_active
) != -1) {
456 /* KGDB CPU roundup */
457 kgdb_nmicallback(raw_smp_processor_id(), regs
);
458 was_in_debug_nmi
[raw_smp_processor_id()] = 1;
459 touch_nmi_watchdog();
465 /* Just ignore, we will handle the roundup on DIE_NMI. */
469 if (was_in_debug_nmi
[raw_smp_processor_id()]) {
470 was_in_debug_nmi
[raw_smp_processor_id()] = 0;
475 case DIE_NMIWATCHDOG
:
476 if (atomic_read(&kgdb_active
) != -1) {
477 /* KGDB CPU roundup: */
478 kgdb_nmicallback(raw_smp_processor_id(), regs
);
481 /* Enter debugger: */
485 if (atomic_read(&kgdb_cpu_doing_single_step
) ==
486 raw_smp_processor_id()) {
488 return single_step_cont(regs
, args
);
490 } else if (test_thread_flag(TIF_SINGLESTEP
))
491 /* This means a user thread is single stepping
492 * a system call which should be ignored
501 if (kgdb_handle_exception(args
->trapnr
, args
->signr
, args
->err
, regs
))
504 /* Must touch watchdog before return to normal operation */
505 touch_nmi_watchdog();
510 kgdb_notify(struct notifier_block
*self
, unsigned long cmd
, void *ptr
)
515 local_irq_save(flags
);
516 ret
= __kgdb_notify(ptr
, cmd
);
517 local_irq_restore(flags
);
522 static struct notifier_block kgdb_notifier
= {
523 .notifier_call
= kgdb_notify
,
526 * Lowest-prio notifier priority, we want to be notified last:
528 .priority
= -INT_MAX
,
532 * kgdb_arch_init - Perform any architecture specific initalization.
534 * This function will handle the initalization of any architecture
535 * specific callbacks.
537 int kgdb_arch_init(void)
539 return register_die_notifier(&kgdb_notifier
);
543 * kgdb_arch_exit - Perform any architecture specific uninitalization.
545 * This function will handle the uninitalization of any architecture
546 * specific callbacks, for dynamic registration and unregistration.
548 void kgdb_arch_exit(void)
550 unregister_die_notifier(&kgdb_notifier
);
555 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
556 * @exception: Exception vector number
557 * @regs: Current &struct pt_regs.
559 * On some architectures we need to skip a breakpoint exception when
560 * it occurs after a breakpoint has been removed.
562 * Skip an int3 exception when it occurs after a breakpoint has been
563 * removed. Backtrack eip by 1 since the int3 would have caused it to
566 int kgdb_skipexception(int exception
, struct pt_regs
*regs
)
568 if (exception
== 3 && kgdb_isremovedbreak(regs
->ip
- 1)) {
575 unsigned long kgdb_arch_pc(int exception
, struct pt_regs
*regs
)
578 return instruction_pointer(regs
) - 1;
579 return instruction_pointer(regs
);
582 struct kgdb_arch arch_kgdb_ops
= {
583 /* Breakpoint instruction: */
584 .gdb_bpt_instr
= { 0xcc },
585 .flags
= KGDB_HW_BREAKPOINT
,
586 .set_hw_breakpoint
= kgdb_set_hw_break
,
587 .remove_hw_breakpoint
= kgdb_remove_hw_break
,
588 .remove_all_hw_break
= kgdb_remove_all_hw_break
,
589 .correct_hw_break
= kgdb_correct_hw_break
,