2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
7 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2004 Thiemo Seufer
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/stddef.h>
17 #include <linux/unistd.h>
18 #include <linux/ptrace.h>
19 #include <linux/slab.h>
20 #include <linux/mman.h>
21 #include <linux/personality.h>
22 #include <linux/sys.h>
23 #include <linux/user.h>
24 #include <linux/a.out.h>
25 #include <linux/init.h>
26 #include <linux/completion.h>
27 #include <linux/kallsyms.h>
30 #include <asm/bootinfo.h>
34 #include <asm/pgtable.h>
35 #include <asm/system.h>
36 #include <asm/mipsregs.h>
37 #include <asm/processor.h>
38 #include <asm/uaccess.h>
41 #include <asm/isadep.h>
43 #ifdef CONFIG_MIPS_MT_SMTC
44 #include <asm/mipsmtregs.h>
45 extern void smtc_idle_loop_hook(void);
46 #endif /* CONFIG_MIPS_MT_SMTC */
49 * The idle thread. There's no useful work to be done, so just try to conserve
50 * power and have a low exit latency (ie sit in a loop waiting for somebody to
51 * say that they'd like to reschedule)
53 ATTRIB_NORET
void cpu_idle(void)
55 /* endless idle loop with no priority at all */
57 while (!need_resched()) {
58 #ifdef CONFIG_MIPS_MT_SMTC
59 smtc_idle_loop_hook();
60 #endif /* CONFIG_MIPS_MT_SMTC */
64 preempt_enable_no_resched();
71 * Native o32 and N64 ABI without DSP ASE
73 struct mips_abi mips_abi
= {
74 .do_signal
= do_signal
,
75 #ifdef CONFIG_TRAD_SIGNALS
76 .setup_frame
= setup_frame
,
78 .setup_rt_frame
= setup_rt_frame
81 #ifdef CONFIG_MIPS32_O32
83 * o32 compatibility on 64-bit kernels, without DSP ASE
85 struct mips_abi mips_abi_32
= {
86 .do_signal
= do_signal32
,
87 .setup_frame
= setup_frame_32
,
88 .setup_rt_frame
= setup_rt_frame_32
90 #endif /* CONFIG_MIPS32_O32 */
92 #ifdef CONFIG_MIPS32_N32
94 * N32 on 64-bit kernels, without DSP ASE
96 struct mips_abi mips_abi_n32
= {
97 .do_signal
= do_signal
,
98 .setup_rt_frame
= setup_rt_frame_n32
100 #endif /* CONFIG_MIPS32_N32 */
102 asmlinkage
void ret_from_fork(void);
104 void start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long sp
)
106 unsigned long status
;
108 /* New thread loses kernel privileges. */
109 status
= regs
->cp0_status
& ~(ST0_CU0
|ST0_CU1
|KU_MASK
);
112 status
|= (current
->thread
.mflags
& MF_32BIT_REGS
) ? 0 : ST0_FR
;
115 regs
->cp0_status
= status
;
122 current_thread_info()->addr_limit
= USER_DS
;
125 void exit_thread(void)
129 void flush_thread(void)
133 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long usp
,
134 unsigned long unused
, struct task_struct
*p
, struct pt_regs
*regs
)
136 struct thread_info
*ti
= task_thread_info(p
);
137 struct pt_regs
*childregs
;
139 p
->set_child_tid
= p
->clear_child_tid
= NULL
;
141 childksp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
- 32;
153 /* set up new TSS. */
154 childregs
= (struct pt_regs
*) childksp
- 1;
156 childregs
->regs
[7] = 0; /* Clear error flag */
158 #if defined(CONFIG_BINFMT_IRIX)
159 if (current
->personality
!= PER_LINUX
) {
160 /* Under IRIX things are a little different. */
161 childregs
->regs
[3] = 1;
165 childregs
->regs
[2] = 0; /* Child gets zero as return value */
166 regs
->regs
[2] = p
->pid
;
168 if (childregs
->cp0_status
& ST0_CU0
) {
169 childregs
->regs
[28] = (unsigned long) ti
;
170 childregs
->regs
[29] = childksp
;
171 ti
->addr_limit
= KERNEL_DS
;
173 childregs
->regs
[29] = usp
;
174 ti
->addr_limit
= USER_DS
;
176 p
->thread
.reg29
= (unsigned long) childregs
;
177 p
->thread
.reg31
= (unsigned long) ret_from_fork
;
180 * New tasks lose permission to use the fpu. This accelerates context
181 * switching for most programs since they don't use the fpu.
183 p
->thread
.cp0_status
= read_c0_status() & ~(ST0_CU2
|ST0_CU1
);
184 childregs
->cp0_status
&= ~(ST0_CU2
|ST0_CU1
);
185 clear_tsk_thread_flag(p
, TIF_USEDFPU
);
187 #ifdef CONFIG_MIPS_MT_FPAFF
189 * FPU affinity support is cleaner if we track the
190 * user-visible CPU affinity from the very beginning.
191 * The generic cpus_allowed mask will already have
192 * been copied from the parent before copy_thread
195 p
->thread
.user_cpus_allowed
= p
->cpus_allowed
;
196 #endif /* CONFIG_MIPS_MT_FPAFF */
198 if (clone_flags
& CLONE_SETTLS
)
199 ti
->tp_value
= regs
->regs
[7];
204 /* Fill in the fpu structure for a core dump.. */
205 int dump_fpu(struct pt_regs
*regs
, elf_fpregset_t
*r
)
207 memcpy(r
, ¤t
->thread
.fpu
, sizeof(current
->thread
.fpu
));
212 void elf_dump_regs(elf_greg_t
*gp
, struct pt_regs
*regs
)
216 for (i
= 0; i
< EF_R0
; i
++)
219 for (i
= 1; i
<= 31; i
++)
220 gp
[EF_R0
+ i
] = regs
->regs
[i
];
223 gp
[EF_LO
] = regs
->lo
;
224 gp
[EF_HI
] = regs
->hi
;
225 gp
[EF_CP0_EPC
] = regs
->cp0_epc
;
226 gp
[EF_CP0_BADVADDR
] = regs
->cp0_badvaddr
;
227 gp
[EF_CP0_STATUS
] = regs
->cp0_status
;
228 gp
[EF_CP0_CAUSE
] = regs
->cp0_cause
;
234 int dump_task_regs (struct task_struct
*tsk
, elf_gregset_t
*regs
)
236 elf_dump_regs(*regs
, task_pt_regs(tsk
));
240 int dump_task_fpu (struct task_struct
*t
, elf_fpregset_t
*fpr
)
242 memcpy(fpr
, &t
->thread
.fpu
, sizeof(current
->thread
.fpu
));
248 * Create a kernel thread
250 ATTRIB_NORET
void kernel_thread_helper(void *arg
, int (*fn
)(void *))
255 long kernel_thread(int (*fn
)(void *), void *arg
, unsigned long flags
)
259 memset(®s
, 0, sizeof(regs
));
261 regs
.regs
[4] = (unsigned long) arg
;
262 regs
.regs
[5] = (unsigned long) fn
;
263 regs
.cp0_epc
= (unsigned long) kernel_thread_helper
;
264 regs
.cp0_status
= read_c0_status();
265 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
266 regs
.cp0_status
&= ~(ST0_KUP
| ST0_IEC
);
267 regs
.cp0_status
|= ST0_IEP
;
269 regs
.cp0_status
|= ST0_EXL
;
272 /* Ok, create the new process.. */
273 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
, 0, ®s
, 0, NULL
, NULL
);
279 struct mips_frame_info
{
281 unsigned long func_size
;
286 static inline int is_ra_save_ins(union mips_instruction
*ip
)
288 /* sw / sd $ra, offset($sp) */
289 return (ip
->i_format
.opcode
== sw_op
|| ip
->i_format
.opcode
== sd_op
) &&
290 ip
->i_format
.rs
== 29 &&
291 ip
->i_format
.rt
== 31;
294 static inline int is_jal_jalr_jr_ins(union mips_instruction
*ip
)
296 if (ip
->j_format
.opcode
== jal_op
)
298 if (ip
->r_format
.opcode
!= spec_op
)
300 return ip
->r_format
.func
== jalr_op
|| ip
->r_format
.func
== jr_op
;
303 static inline int is_sp_move_ins(union mips_instruction
*ip
)
305 /* addiu/daddiu sp,sp,-imm */
306 if (ip
->i_format
.rs
!= 29 || ip
->i_format
.rt
!= 29)
308 if (ip
->i_format
.opcode
== addiu_op
|| ip
->i_format
.opcode
== daddiu_op
)
313 static int get_frame_info(struct mips_frame_info
*info
)
315 union mips_instruction
*ip
= info
->func
;
316 unsigned max_insns
= info
->func_size
/ sizeof(union mips_instruction
);
319 info
->pc_offset
= -1;
320 info
->frame_size
= 0;
326 max_insns
= 128U; /* unknown function size */
327 max_insns
= min(128U, max_insns
);
329 for (i
= 0; i
< max_insns
; i
++, ip
++) {
331 if (is_jal_jalr_jr_ins(ip
))
333 if (!info
->frame_size
) {
334 if (is_sp_move_ins(ip
))
335 info
->frame_size
= - ip
->i_format
.simmediate
;
338 if (info
->pc_offset
== -1 && is_ra_save_ins(ip
)) {
340 ip
->i_format
.simmediate
/ sizeof(long);
344 if (info
->frame_size
&& info
->pc_offset
>= 0) /* nested */
346 if (info
->pc_offset
< 0) /* leaf */
348 /* prologue seems boggus... */
353 static struct mips_frame_info schedule_mfi __read_mostly
;
355 static int __init
frame_info_init(void)
357 unsigned long size
= 0;
358 #ifdef CONFIG_KALLSYMS
361 char namebuf
[KSYM_NAME_LEN
+ 1];
363 kallsyms_lookup((unsigned long)schedule
, &size
, &ofs
, &modname
, namebuf
);
365 schedule_mfi
.func
= schedule
;
366 schedule_mfi
.func_size
= size
;
368 get_frame_info(&schedule_mfi
);
371 * Without schedule() frame info, result given by
372 * thread_saved_pc() and get_wchan() are not reliable.
374 if (schedule_mfi
.pc_offset
< 0)
375 printk("Can't analyze schedule() prologue at %p\n", schedule
);
380 arch_initcall(frame_info_init
);
383 * Return saved PC of a blocked thread.
385 unsigned long thread_saved_pc(struct task_struct
*tsk
)
387 struct thread_struct
*t
= &tsk
->thread
;
389 /* New born processes are a special case */
390 if (t
->reg31
== (unsigned long) ret_from_fork
)
392 if (schedule_mfi
.pc_offset
< 0)
394 return ((unsigned long *)t
->reg29
)[schedule_mfi
.pc_offset
];
398 #ifdef CONFIG_KALLSYMS
399 /* used by show_backtrace() */
400 unsigned long unwind_stack(struct task_struct
*task
, unsigned long *sp
,
401 unsigned long pc
, unsigned long ra
)
403 unsigned long stack_page
;
404 struct mips_frame_info info
;
406 char namebuf
[KSYM_NAME_LEN
+ 1];
407 unsigned long size
, ofs
;
410 stack_page
= (unsigned long)task_stack_page(task
);
414 if (!kallsyms_lookup(pc
, &size
, &ofs
, &modname
, namebuf
))
417 * Return ra if an exception occured at the first instruction
419 if (unlikely(ofs
== 0))
422 info
.func
= (void *)(pc
- ofs
);
423 info
.func_size
= ofs
; /* analyze from start to ofs */
424 leaf
= get_frame_info(&info
);
428 if (*sp
< stack_page
||
429 *sp
+ info
.frame_size
> stack_page
+ THREAD_SIZE
- 32)
434 * For some extreme cases, get_frame_info() can
435 * consider wrongly a nested function as a leaf
436 * one. In that cases avoid to return always the
439 pc
= pc
!= ra
? ra
: 0;
441 pc
= ((unsigned long *)(*sp
))[info
.pc_offset
];
443 *sp
+= info
.frame_size
;
444 return __kernel_text_address(pc
) ? pc
: 0;
449 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
451 unsigned long get_wchan(struct task_struct
*task
)
453 unsigned long pc
= 0;
454 #ifdef CONFIG_KALLSYMS
458 if (!task
|| task
== current
|| task
->state
== TASK_RUNNING
)
460 if (!task_stack_page(task
))
463 pc
= thread_saved_pc(task
);
465 #ifdef CONFIG_KALLSYMS
466 sp
= task
->thread
.reg29
+ schedule_mfi
.frame_size
;
468 while (in_sched_functions(pc
))
469 pc
= unwind_stack(task
, &sp
, pc
, 0);