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authorJason Wessel <jason.wessel@windriver.com>2008-07-29 16:58:53 -0400
committerRalf Baechle <ralf@linux-mips.org>2008-07-30 16:54:42 -0400
commit8854700115ecf8aa6f087aa915b7b6cf18090d39 (patch)
tree3338d7aed80d715e0576783e0fecf30cc507a9a7 /arch/mips/kernel
parent8d60a903d986ffa26c41f0092320a3b9da20bfaf (diff)
[MIPS] kgdb: add arch support for the kernel's kgdb core
The new kgdb architecture specific handler registers and unregisters dynamically for exceptions depending on when you configure a kgdb I/O driver. Aside from initializing the exceptions earlier in the boot process, kgdb should have no impact on a device when it is compiled in so long as an I/O module is not configured for use. There have been quite a number of contributors during the existence of this patch (see arch/mips/kernel/kgdb.c). Most recently Jason re-wrote the mips kgdb logic to use the die notification handlers. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/Makefile1
-rw-r--r--arch/mips/kernel/irq.c15
-rw-r--r--arch/mips/kernel/kgdb.c281
-rw-r--r--arch/mips/kernel/traps.c21
4 files changed, 318 insertions, 0 deletions
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 73ff048eaa55..706f93974797 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_MIPS32_COMPAT) += linux32.o ptrace32.o signal32.o
71obj-$(CONFIG_MIPS32_N32) += binfmt_elfn32.o scall64-n32.o signal_n32.o 71obj-$(CONFIG_MIPS32_N32) += binfmt_elfn32.o scall64-n32.o signal_n32.o
72obj-$(CONFIG_MIPS32_O32) += binfmt_elfo32.o scall64-o32.o 72obj-$(CONFIG_MIPS32_O32) += binfmt_elfo32.o scall64-o32.o
73 73
74obj-$(CONFIG_KGDB) += kgdb.o
74obj-$(CONFIG_PROC_FS) += proc.o 75obj-$(CONFIG_PROC_FS) += proc.o
75 76
76obj-$(CONFIG_64BIT) += cpu-bugs64.o 77obj-$(CONFIG_64BIT) += cpu-bugs64.o
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index 8acba0880d9f..4b4007b3083a 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -21,11 +21,16 @@
21#include <linux/sched.h> 21#include <linux/sched.h>
22#include <linux/seq_file.h> 22#include <linux/seq_file.h>
23#include <linux/kallsyms.h> 23#include <linux/kallsyms.h>
24#include <linux/kgdb.h>
24 25
25#include <asm/atomic.h> 26#include <asm/atomic.h>
26#include <asm/system.h> 27#include <asm/system.h>
27#include <asm/uaccess.h> 28#include <asm/uaccess.h>
28 29
30#ifdef CONFIG_KGDB
31int kgdb_early_setup;
32#endif
33
29static unsigned long irq_map[NR_IRQS / BITS_PER_LONG]; 34static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
30 35
31int allocate_irqno(void) 36int allocate_irqno(void)
@@ -130,8 +135,18 @@ void __init init_IRQ(void)
130{ 135{
131 int i; 136 int i;
132 137
138#ifdef CONFIG_KGDB
139 if (kgdb_early_setup)
140 return;
141#endif
142
133 for (i = 0; i < NR_IRQS; i++) 143 for (i = 0; i < NR_IRQS; i++)
134 set_irq_noprobe(i); 144 set_irq_noprobe(i);
135 145
136 arch_init_irq(); 146 arch_init_irq();
147
148#ifdef CONFIG_KGDB
149 if (!kgdb_early_setup)
150 kgdb_early_setup = 1;
151#endif
137} 152}
diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
new file mode 100644
index 000000000000..c5a8b2d21ca4
--- /dev/null
+++ b/arch/mips/kernel/kgdb.c
@@ -0,0 +1,281 @@
1/*
2 * Originally written by Glenn Engel, Lake Stevens Instrument Division
3 *
4 * Contributed by HP Systems
5 *
6 * Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
7 * Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
8 *
9 * Copyright (C) 1995 Andreas Busse
10 *
11 * Copyright (C) 2003 MontaVista Software Inc.
12 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
13 *
14 * Copyright (C) 2004-2005 MontaVista Software Inc.
15 * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
16 *
17 * Copyright (C) 2007-2008 Wind River Systems, Inc.
18 * Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
19 *
20 * This file is licensed under the terms of the GNU General Public License
21 * version 2. This program is licensed "as is" without any warranty of any
22 * kind, whether express or implied.
23 */
24
25#include <linux/ptrace.h> /* for linux pt_regs struct */
26#include <linux/kgdb.h>
27#include <linux/kdebug.h>
28#include <linux/sched.h>
29#include <asm/inst.h>
30#include <asm/fpu.h>
31#include <asm/cacheflush.h>
32#include <asm/processor.h>
33#include <asm/sigcontext.h>
34
35static struct hard_trap_info {
36 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
37 unsigned char signo; /* Signal that we map this trap into */
38} hard_trap_info[] = {
39 { 6, SIGBUS }, /* instruction bus error */
40 { 7, SIGBUS }, /* data bus error */
41 { 9, SIGTRAP }, /* break */
42/* { 11, SIGILL }, */ /* CPU unusable */
43 { 12, SIGFPE }, /* overflow */
44 { 13, SIGTRAP }, /* trap */
45 { 14, SIGSEGV }, /* virtual instruction cache coherency */
46 { 15, SIGFPE }, /* floating point exception */
47 { 23, SIGSEGV }, /* watch */
48 { 31, SIGSEGV }, /* virtual data cache coherency */
49 { 0, 0} /* Must be last */
50};
51
52void arch_kgdb_breakpoint(void)
53{
54 __asm__ __volatile__(
55 ".globl breakinst\n\t"
56 ".set\tnoreorder\n\t"
57 "nop\n"
58 "breakinst:\tbreak\n\t"
59 "nop\n\t"
60 ".set\treorder");
61}
62
63static void kgdb_call_nmi_hook(void *ignored)
64{
65 kgdb_nmicallback(raw_smp_processor_id(), (void *)0);
66}
67
68void kgdb_roundup_cpus(unsigned long flags)
69{
70 local_irq_enable();
71 smp_call_function(kgdb_call_nmi_hook, NULL, NULL);
72 local_irq_disable();
73}
74
75static int compute_signal(int tt)
76{
77 struct hard_trap_info *ht;
78
79 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
80 if (ht->tt == tt)
81 return ht->signo;
82
83 return SIGHUP; /* default for things we don't know about */
84}
85
86void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
87{
88 int reg;
89
90#if (KGDB_GDB_REG_SIZE == 32)
91 u32 *ptr = (u32 *)gdb_regs;
92#else
93 u64 *ptr = (u64 *)gdb_regs;
94#endif
95
96 for (reg = 0; reg < 32; reg++)
97 *(ptr++) = regs->regs[reg];
98
99 *(ptr++) = regs->cp0_status;
100 *(ptr++) = regs->lo;
101 *(ptr++) = regs->hi;
102 *(ptr++) = regs->cp0_badvaddr;
103 *(ptr++) = regs->cp0_cause;
104 *(ptr++) = regs->cp0_epc;
105
106 /* FP REGS */
107 if (!(current && (regs->cp0_status & ST0_CU1)))
108 return;
109
110 save_fp(current);
111 for (reg = 0; reg < 32; reg++)
112 *(ptr++) = current->thread.fpu.fpr[reg];
113}
114
115void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
116{
117 int reg;
118
119#if (KGDB_GDB_REG_SIZE == 32)
120 const u32 *ptr = (u32 *)gdb_regs;
121#else
122 const u64 *ptr = (u64 *)gdb_regs;
123#endif
124
125 for (reg = 0; reg < 32; reg++)
126 regs->regs[reg] = *(ptr++);
127
128 regs->cp0_status = *(ptr++);
129 regs->lo = *(ptr++);
130 regs->hi = *(ptr++);
131 regs->cp0_badvaddr = *(ptr++);
132 regs->cp0_cause = *(ptr++);
133 regs->cp0_epc = *(ptr++);
134
135 /* FP REGS from current */
136 if (!(current && (regs->cp0_status & ST0_CU1)))
137 return;
138
139 for (reg = 0; reg < 32; reg++)
140 current->thread.fpu.fpr[reg] = *(ptr++);
141 restore_fp(current);
142}
143
144/*
145 * Similar to regs_to_gdb_regs() except that process is sleeping and so
146 * we may not be able to get all the info.
147 */
148void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
149{
150 int reg;
151 struct thread_info *ti = task_thread_info(p);
152 unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
153 struct pt_regs *regs = (struct pt_regs *)ksp - 1;
154#if (KGDB_GDB_REG_SIZE == 32)
155 u32 *ptr = (u32 *)gdb_regs;
156#else
157 u64 *ptr = (u64 *)gdb_regs;
158#endif
159
160 for (reg = 0; reg < 16; reg++)
161 *(ptr++) = regs->regs[reg];
162
163 /* S0 - S7 */
164 for (reg = 16; reg < 24; reg++)
165 *(ptr++) = regs->regs[reg];
166
167 for (reg = 24; reg < 28; reg++)
168 *(ptr++) = 0;
169
170 /* GP, SP, FP, RA */
171 for (reg = 28; reg < 32; reg++)
172 *(ptr++) = regs->regs[reg];
173
174 *(ptr++) = regs->cp0_status;
175 *(ptr++) = regs->lo;
176 *(ptr++) = regs->hi;
177 *(ptr++) = regs->cp0_badvaddr;
178 *(ptr++) = regs->cp0_cause;
179 *(ptr++) = regs->cp0_epc;
180}
181
182/*
183 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
184 * then try to fall into the debugger
185 */
186static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
187 void *ptr)
188{
189 struct die_args *args = (struct die_args *)ptr;
190 struct pt_regs *regs = args->regs;
191 int trap = (regs->cp0_cause & 0x7c) >> 2;
192
193 if (fixup_exception(regs))
194 return NOTIFY_DONE;
195
196 /* Userpace events, ignore. */
197 if (user_mode(regs))
198 return NOTIFY_DONE;
199
200 if (atomic_read(&kgdb_active) != -1)
201 kgdb_nmicallback(smp_processor_id(), regs);
202
203 if (kgdb_handle_exception(trap, compute_signal(trap), 0, regs))
204 return NOTIFY_DONE;
205
206 if (atomic_read(&kgdb_setting_breakpoint))
207 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
208 regs->cp0_epc += 4;
209
210 /* In SMP mode, __flush_cache_all does IPI */
211 local_irq_enable();
212 __flush_cache_all();
213
214 return NOTIFY_STOP;
215}
216
217static struct notifier_block kgdb_notifier = {
218 .notifier_call = kgdb_mips_notify,
219};
220
221/*
222 * Handle the 's' and 'c' commands
223 */
224int kgdb_arch_handle_exception(int vector, int signo, int err_code,
225 char *remcom_in_buffer, char *remcom_out_buffer,
226 struct pt_regs *regs)
227{
228 char *ptr;
229 unsigned long address;
230 int cpu = smp_processor_id();
231
232 switch (remcom_in_buffer[0]) {
233 case 's':
234 case 'c':
235 /* handle the optional parameter */
236 ptr = &remcom_in_buffer[1];
237 if (kgdb_hex2long(&ptr, &address))
238 regs->cp0_epc = address;
239
240 atomic_set(&kgdb_cpu_doing_single_step, -1);
241 if (remcom_in_buffer[0] == 's')
242 if (kgdb_contthread)
243 atomic_set(&kgdb_cpu_doing_single_step, cpu);
244
245 return 0;
246 }
247
248 return -1;
249}
250
251struct kgdb_arch arch_kgdb_ops;
252
253/*
254 * We use kgdb_early_setup so that functions we need to call now don't
255 * cause trouble when called again later.
256 */
257int kgdb_arch_init(void)
258{
259 union mips_instruction insn = {
260 .r_format = {
261 .opcode = spec_op,
262 .func = break_op,
263 }
264 };
265 memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);
266
267 register_die_notifier(&kgdb_notifier);
268
269 return 0;
270}
271
272/*
273 * kgdb_arch_exit - Perform any architecture specific uninitalization.
274 *
275 * This function will handle the uninitalization of any architecture
276 * specific callbacks, for dynamic registration and unregistration.
277 */
278void kgdb_arch_exit(void)
279{
280 unregister_die_notifier(&kgdb_notifier);
281}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index b8ea4e9d0d87..426cced1e9dc 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -23,6 +23,8 @@
23#include <linux/bootmem.h> 23#include <linux/bootmem.h>
24#include <linux/interrupt.h> 24#include <linux/interrupt.h>
25#include <linux/ptrace.h> 25#include <linux/ptrace.h>
26#include <linux/kgdb.h>
27#include <linux/kdebug.h>
26 28
27#include <asm/bootinfo.h> 29#include <asm/bootinfo.h>
28#include <asm/branch.h> 30#include <asm/branch.h>
@@ -425,6 +427,10 @@ asmlinkage void do_be(struct pt_regs *regs)
425 printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n", 427 printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
426 data ? "Data" : "Instruction", 428 data ? "Data" : "Instruction",
427 field, regs->cp0_epc, field, regs->regs[31]); 429 field, regs->cp0_epc, field, regs->regs[31]);
430 if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
431 == NOTIFY_STOP)
432 return;
433
428 die_if_kernel("Oops", regs); 434 die_if_kernel("Oops", regs);
429 force_sig(SIGBUS, current); 435 force_sig(SIGBUS, current);
430} 436}
@@ -623,6 +629,9 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
623{ 629{
624 siginfo_t info; 630 siginfo_t info;
625 631
632 if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
633 == NOTIFY_STOP)
634 return;
626 die_if_kernel("FP exception in kernel code", regs); 635 die_if_kernel("FP exception in kernel code", regs);
627 636
628 if (fcr31 & FPU_CSR_UNI_X) { 637 if (fcr31 & FPU_CSR_UNI_X) {
@@ -682,6 +691,9 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
682 siginfo_t info; 691 siginfo_t info;
683 char b[40]; 692 char b[40];
684 693
694 if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
695 return;
696
685 /* 697 /*
686 * A short test says that IRIX 5.3 sends SIGTRAP for all trap 698 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
687 * insns, even for trap and break codes that indicate arithmetic 699 * insns, even for trap and break codes that indicate arithmetic
@@ -762,6 +774,10 @@ asmlinkage void do_ri(struct pt_regs *regs)
762 unsigned int opcode = 0; 774 unsigned int opcode = 0;
763 int status = -1; 775 int status = -1;
764 776
777 if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
778 == NOTIFY_STOP)
779 return;
780
765 die_if_kernel("Reserved instruction in kernel code", regs); 781 die_if_kernel("Reserved instruction in kernel code", regs);
766 782
767 if (unlikely(compute_return_epc(regs) < 0)) 783 if (unlikely(compute_return_epc(regs) < 0))
@@ -1537,6 +1553,11 @@ void __init trap_init(void)
1537 extern char except_vec4; 1553 extern char except_vec4;
1538 unsigned long i; 1554 unsigned long i;
1539 1555
1556#if defined(CONFIG_KGDB)
1557 if (kgdb_early_setup)
1558 return; /* Already done */
1559#endif
1560
1540 if (cpu_has_veic || cpu_has_vint) 1561 if (cpu_has_veic || cpu_has_vint)
1541 ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64); 1562 ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
1542 else 1563 else