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
10 * Copyright (C) 2013 Imagination Technologies Ltd.
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/tick.h>
15 #include <linux/kernel.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/export.h>
20 #include <linux/ptrace.h>
21 #include <linux/mman.h>
22 #include <linux/personality.h>
23 #include <linux/sys.h>
24 #include <linux/init.h>
25 #include <linux/completion.h>
26 #include <linux/kallsyms.h>
27 #include <linux/random.h>
30 #include <asm/bootinfo.h>
35 #include <asm/pgtable.h>
36 #include <asm/mipsregs.h>
37 #include <asm/processor.h>
39 #include <asm/uaccess.h>
42 #include <asm/isadep.h>
44 #include <asm/stacktrace.h>
45 #include <asm/irq_regs.h>
47 #ifdef CONFIG_HOTPLUG_CPU
48 void arch_cpu_idle_dead(void)
50 /* What the heck is this check doing ? */
51 if (!cpu_isset(smp_processor_id(), cpu_callin_map
))
56 asmlinkage
void ret_from_fork(void);
57 asmlinkage
void ret_from_kernel_thread(void);
59 void start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long sp
)
63 /* New thread loses kernel privileges. */
64 status
= regs
->cp0_status
& ~(ST0_CU0
|ST0_CU1
|ST0_FR
|KU_MASK
);
66 regs
->cp0_status
= status
;
70 clear_thread_flag(TIF_USEDMSA
);
71 clear_thread_flag(TIF_MSA_CTX_LIVE
);
77 void exit_thread(void)
81 void flush_thread(void)
85 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
88 * Save any process state which is live in hardware registers to the
89 * parent context prior to duplication. This prevents the new child
90 * state becoming stale if the parent is preempted before copy_thread()
91 * gets a chance to save the parent's live hardware registers to the
98 else if (is_fpu_owner())
109 int copy_thread(unsigned long clone_flags
, unsigned long usp
,
110 unsigned long arg
, struct task_struct
*p
)
112 struct thread_info
*ti
= task_thread_info(p
);
113 struct pt_regs
*childregs
, *regs
= current_pt_regs();
114 unsigned long childksp
;
115 p
->set_child_tid
= p
->clear_child_tid
= NULL
;
117 childksp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
- 32;
119 /* set up new TSS. */
120 childregs
= (struct pt_regs
*) childksp
- 1;
121 /* Put the stack after the struct pt_regs. */
122 childksp
= (unsigned long) childregs
;
123 p
->thread
.cp0_status
= read_c0_status() & ~(ST0_CU2
|ST0_CU1
);
124 if (unlikely(p
->flags
& PF_KTHREAD
)) {
125 unsigned long status
= p
->thread
.cp0_status
;
126 memset(childregs
, 0, sizeof(struct pt_regs
));
127 ti
->addr_limit
= KERNEL_DS
;
128 p
->thread
.reg16
= usp
; /* fn */
129 p
->thread
.reg17
= arg
;
130 p
->thread
.reg29
= childksp
;
131 p
->thread
.reg31
= (unsigned long) ret_from_kernel_thread
;
132 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
133 status
= (status
& ~(ST0_KUP
| ST0_IEP
| ST0_IEC
)) |
134 ((status
& (ST0_KUC
| ST0_IEC
)) << 2);
138 childregs
->cp0_status
= status
;
142 childregs
->regs
[7] = 0; /* Clear error flag */
143 childregs
->regs
[2] = 0; /* Child gets zero as return value */
145 childregs
->regs
[29] = usp
;
146 ti
->addr_limit
= USER_DS
;
148 p
->thread
.reg29
= (unsigned long) childregs
;
149 p
->thread
.reg31
= (unsigned long) ret_from_fork
;
152 * New tasks lose permission to use the fpu. This accelerates context
153 * switching for most programs since they don't use the fpu.
155 childregs
->cp0_status
&= ~(ST0_CU2
|ST0_CU1
);
157 clear_tsk_thread_flag(p
, TIF_USEDFPU
);
158 clear_tsk_thread_flag(p
, TIF_USEDMSA
);
159 clear_tsk_thread_flag(p
, TIF_MSA_CTX_LIVE
);
161 #ifdef CONFIG_MIPS_MT_FPAFF
162 clear_tsk_thread_flag(p
, TIF_FPUBOUND
);
163 #endif /* CONFIG_MIPS_MT_FPAFF */
165 if (clone_flags
& CLONE_SETTLS
)
166 ti
->tp_value
= regs
->regs
[7];
171 #ifdef CONFIG_CC_STACKPROTECTOR
172 #include <linux/stackprotector.h>
173 unsigned long __stack_chk_guard __read_mostly
;
174 EXPORT_SYMBOL(__stack_chk_guard
);
177 struct mips_frame_info
{
179 unsigned long func_size
;
184 #define J_TARGET(pc,target) \
185 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
187 static inline int is_ra_save_ins(union mips_instruction
*ip
)
189 #ifdef CONFIG_CPU_MICROMIPS
190 union mips_instruction mmi
;
194 * swm16 reglist,offset(sp)
195 * swm32 reglist,offset(sp)
197 * jradiussp - NOT SUPPORTED
199 * microMIPS is way more fun...
201 if (mm_insn_16bit(ip
->halfword
[0])) {
202 mmi
.word
= (ip
->halfword
[0] << 16);
203 return (mmi
.mm16_r5_format
.opcode
== mm_swsp16_op
&&
204 mmi
.mm16_r5_format
.rt
== 31) ||
205 (mmi
.mm16_m_format
.opcode
== mm_pool16c_op
&&
206 mmi
.mm16_m_format
.func
== mm_swm16_op
);
209 mmi
.halfword
[0] = ip
->halfword
[1];
210 mmi
.halfword
[1] = ip
->halfword
[0];
211 return (mmi
.mm_m_format
.opcode
== mm_pool32b_op
&&
212 mmi
.mm_m_format
.rd
> 9 &&
213 mmi
.mm_m_format
.base
== 29 &&
214 mmi
.mm_m_format
.func
== mm_swm32_func
) ||
215 (mmi
.i_format
.opcode
== mm_sw32_op
&&
216 mmi
.i_format
.rs
== 29 &&
217 mmi
.i_format
.rt
== 31);
220 /* sw / sd $ra, offset($sp) */
221 return (ip
->i_format
.opcode
== sw_op
|| ip
->i_format
.opcode
== sd_op
) &&
222 ip
->i_format
.rs
== 29 &&
223 ip
->i_format
.rt
== 31;
227 static inline int is_jump_ins(union mips_instruction
*ip
)
229 #ifdef CONFIG_CPU_MICROMIPS
231 * jr16,jrc,jalr16,jalr16
233 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
234 * jraddiusp - NOT SUPPORTED
236 * microMIPS is kind of more fun...
238 union mips_instruction mmi
;
240 mmi
.word
= (ip
->halfword
[0] << 16);
242 if ((mmi
.mm16_r5_format
.opcode
== mm_pool16c_op
&&
243 (mmi
.mm16_r5_format
.rt
& mm_jr16_op
) == mm_jr16_op
) ||
244 ip
->j_format
.opcode
== mm_jal32_op
)
246 if (ip
->r_format
.opcode
!= mm_pool32a_op
||
247 ip
->r_format
.func
!= mm_pool32axf_op
)
249 return ((ip
->u_format
.uimmediate
>> 6) & mm_jalr_op
) == mm_jalr_op
;
251 if (ip
->j_format
.opcode
== j_op
)
253 if (ip
->j_format
.opcode
== jal_op
)
255 if (ip
->r_format
.opcode
!= spec_op
)
257 return ip
->r_format
.func
== jalr_op
|| ip
->r_format
.func
== jr_op
;
261 static inline int is_sp_move_ins(union mips_instruction
*ip
)
263 #ifdef CONFIG_CPU_MICROMIPS
268 * jradiussp - NOT SUPPORTED
270 * microMIPS is not more fun...
272 if (mm_insn_16bit(ip
->halfword
[0])) {
273 union mips_instruction mmi
;
275 mmi
.word
= (ip
->halfword
[0] << 16);
276 return (mmi
.mm16_r3_format
.opcode
== mm_pool16d_op
&&
277 mmi
.mm16_r3_format
.simmediate
&& mm_addiusp_func
) ||
278 (mmi
.mm16_r5_format
.opcode
== mm_pool16d_op
&&
279 mmi
.mm16_r5_format
.rt
== 29);
281 return ip
->mm_i_format
.opcode
== mm_addiu32_op
&&
282 ip
->mm_i_format
.rt
== 29 && ip
->mm_i_format
.rs
== 29;
284 /* addiu/daddiu sp,sp,-imm */
285 if (ip
->i_format
.rs
!= 29 || ip
->i_format
.rt
!= 29)
287 if (ip
->i_format
.opcode
== addiu_op
|| ip
->i_format
.opcode
== daddiu_op
)
293 static int get_frame_info(struct mips_frame_info
*info
)
295 #ifdef CONFIG_CPU_MICROMIPS
296 union mips_instruction
*ip
= (void *) (((char *) info
->func
) - 1);
298 union mips_instruction
*ip
= info
->func
;
300 unsigned max_insns
= info
->func_size
/ sizeof(union mips_instruction
);
303 info
->pc_offset
= -1;
304 info
->frame_size
= 0;
310 max_insns
= 128U; /* unknown function size */
311 max_insns
= min(128U, max_insns
);
313 for (i
= 0; i
< max_insns
; i
++, ip
++) {
317 if (!info
->frame_size
) {
318 if (is_sp_move_ins(ip
))
320 #ifdef CONFIG_CPU_MICROMIPS
321 if (mm_insn_16bit(ip
->halfword
[0]))
325 if (ip
->halfword
[0] & mm_addiusp_func
)
327 tmp
= (((ip
->halfword
[0] >> 1) & 0x1ff) << 2);
328 info
->frame_size
= -(signed short)(tmp
| ((tmp
& 0x100) ? 0xfe00 : 0));
330 tmp
= (ip
->halfword
[0] >> 1);
331 info
->frame_size
= -(signed short)(tmp
& 0xf);
333 ip
= (void *) &ip
->halfword
[1];
337 info
->frame_size
= - ip
->i_format
.simmediate
;
341 if (info
->pc_offset
== -1 && is_ra_save_ins(ip
)) {
343 ip
->i_format
.simmediate
/ sizeof(long);
347 if (info
->frame_size
&& info
->pc_offset
>= 0) /* nested */
349 if (info
->pc_offset
< 0) /* leaf */
351 /* prologue seems boggus... */
356 static struct mips_frame_info schedule_mfi __read_mostly
;
358 #ifdef CONFIG_KALLSYMS
359 static unsigned long get___schedule_addr(void)
361 return kallsyms_lookup_name("__schedule");
364 static unsigned long get___schedule_addr(void)
366 union mips_instruction
*ip
= (void *)schedule
;
370 for (i
= 0; i
< max_insns
; i
++, ip
++) {
371 if (ip
->j_format
.opcode
== j_op
)
372 return J_TARGET(ip
, ip
->j_format
.target
);
378 static int __init
frame_info_init(void)
380 unsigned long size
= 0;
381 #ifdef CONFIG_KALLSYMS
386 addr
= get___schedule_addr();
388 addr
= (unsigned long)schedule
;
390 #ifdef CONFIG_KALLSYMS
391 kallsyms_lookup_size_offset(addr
, &size
, &ofs
);
393 schedule_mfi
.func
= (void *)addr
;
394 schedule_mfi
.func_size
= size
;
396 get_frame_info(&schedule_mfi
);
399 * Without schedule() frame info, result given by
400 * thread_saved_pc() and get_wchan() are not reliable.
402 if (schedule_mfi
.pc_offset
< 0)
403 printk("Can't analyze schedule() prologue at %p\n", schedule
);
408 arch_initcall(frame_info_init
);
411 * Return saved PC of a blocked thread.
413 unsigned long thread_saved_pc(struct task_struct
*tsk
)
415 struct thread_struct
*t
= &tsk
->thread
;
417 /* New born processes are a special case */
418 if (t
->reg31
== (unsigned long) ret_from_fork
)
420 if (schedule_mfi
.pc_offset
< 0)
422 return ((unsigned long *)t
->reg29
)[schedule_mfi
.pc_offset
];
426 #ifdef CONFIG_KALLSYMS
427 /* generic stack unwinding function */
428 unsigned long notrace
unwind_stack_by_address(unsigned long stack_page
,
433 struct mips_frame_info info
;
434 unsigned long size
, ofs
;
436 extern void ret_from_irq(void);
437 extern void ret_from_exception(void);
443 * If we reached the bottom of interrupt context,
444 * return saved pc in pt_regs.
446 if (pc
== (unsigned long)ret_from_irq
||
447 pc
== (unsigned long)ret_from_exception
) {
448 struct pt_regs
*regs
;
449 if (*sp
>= stack_page
&&
450 *sp
+ sizeof(*regs
) <= stack_page
+ THREAD_SIZE
- 32) {
451 regs
= (struct pt_regs
*)*sp
;
453 if (__kernel_text_address(pc
)) {
454 *sp
= regs
->regs
[29];
455 *ra
= regs
->regs
[31];
461 if (!kallsyms_lookup_size_offset(pc
, &size
, &ofs
))
464 * Return ra if an exception occurred at the first instruction
466 if (unlikely(ofs
== 0)) {
472 info
.func
= (void *)(pc
- ofs
);
473 info
.func_size
= ofs
; /* analyze from start to ofs */
474 leaf
= get_frame_info(&info
);
478 if (*sp
< stack_page
||
479 *sp
+ info
.frame_size
> stack_page
+ THREAD_SIZE
- 32)
484 * For some extreme cases, get_frame_info() can
485 * consider wrongly a nested function as a leaf
486 * one. In that cases avoid to return always the
489 pc
= pc
!= *ra
? *ra
: 0;
491 pc
= ((unsigned long *)(*sp
))[info
.pc_offset
];
493 *sp
+= info
.frame_size
;
495 return __kernel_text_address(pc
) ? pc
: 0;
497 EXPORT_SYMBOL(unwind_stack_by_address
);
499 /* used by show_backtrace() */
500 unsigned long unwind_stack(struct task_struct
*task
, unsigned long *sp
,
501 unsigned long pc
, unsigned long *ra
)
503 unsigned long stack_page
= (unsigned long)task_stack_page(task
);
504 return unwind_stack_by_address(stack_page
, sp
, pc
, ra
);
509 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
511 unsigned long get_wchan(struct task_struct
*task
)
513 unsigned long pc
= 0;
514 #ifdef CONFIG_KALLSYMS
516 unsigned long ra
= 0;
519 if (!task
|| task
== current
|| task
->state
== TASK_RUNNING
)
521 if (!task_stack_page(task
))
524 pc
= thread_saved_pc(task
);
526 #ifdef CONFIG_KALLSYMS
527 sp
= task
->thread
.reg29
+ schedule_mfi
.frame_size
;
529 while (in_sched_functions(pc
))
530 pc
= unwind_stack(task
, &sp
, pc
, &ra
);
538 * Don't forget that the stack pointer must be aligned on a 8 bytes
539 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
541 unsigned long arch_align_stack(unsigned long sp
)
543 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
544 sp
-= get_random_int() & ~PAGE_MASK
;
549 static void arch_dump_stack(void *info
)
551 struct pt_regs
*regs
;
553 regs
= get_irq_regs();
561 void arch_trigger_all_cpu_backtrace(bool include_self
)
563 smp_call_function(arch_dump_stack
, NULL
, 1);