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>
28 #include <linux/prctl.h>
31 #include <asm/bootinfo.h>
36 #include <asm/pgtable.h>
37 #include <asm/mipsregs.h>
38 #include <asm/processor.h>
40 #include <asm/uaccess.h>
43 #include <asm/isadep.h>
45 #include <asm/stacktrace.h>
46 #include <asm/irq_regs.h>
48 #ifdef CONFIG_HOTPLUG_CPU
49 void arch_cpu_idle_dead(void)
51 /* What the heck is this check doing ? */
52 if (!cpu_isset(smp_processor_id(), cpu_callin_map
))
57 asmlinkage
void ret_from_fork(void);
58 asmlinkage
void ret_from_kernel_thread(void);
60 void start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long sp
)
64 /* New thread loses kernel privileges. */
65 status
= regs
->cp0_status
& ~(ST0_CU0
|ST0_CU1
|ST0_FR
|KU_MASK
);
67 regs
->cp0_status
= status
;
71 clear_thread_flag(TIF_USEDMSA
);
72 clear_thread_flag(TIF_MSA_CTX_LIVE
);
78 void exit_thread(void)
82 void flush_thread(void)
86 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
89 * Save any process state which is live in hardware registers to the
90 * parent context prior to duplication. This prevents the new child
91 * state becoming stale if the parent is preempted before copy_thread()
92 * gets a chance to save the parent's live hardware registers to the
99 else if (is_fpu_owner())
110 int copy_thread(unsigned long clone_flags
, unsigned long usp
,
111 unsigned long arg
, struct task_struct
*p
)
113 struct thread_info
*ti
= task_thread_info(p
);
114 struct pt_regs
*childregs
, *regs
= current_pt_regs();
115 unsigned long childksp
;
116 p
->set_child_tid
= p
->clear_child_tid
= NULL
;
118 childksp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
- 32;
120 /* set up new TSS. */
121 childregs
= (struct pt_regs
*) childksp
- 1;
122 /* Put the stack after the struct pt_regs. */
123 childksp
= (unsigned long) childregs
;
124 p
->thread
.cp0_status
= read_c0_status() & ~(ST0_CU2
|ST0_CU1
);
125 if (unlikely(p
->flags
& PF_KTHREAD
)) {
126 unsigned long status
= p
->thread
.cp0_status
;
127 memset(childregs
, 0, sizeof(struct pt_regs
));
128 ti
->addr_limit
= KERNEL_DS
;
129 p
->thread
.reg16
= usp
; /* fn */
130 p
->thread
.reg17
= arg
;
131 p
->thread
.reg29
= childksp
;
132 p
->thread
.reg31
= (unsigned long) ret_from_kernel_thread
;
133 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
134 status
= (status
& ~(ST0_KUP
| ST0_IEP
| ST0_IEC
)) |
135 ((status
& (ST0_KUC
| ST0_IEC
)) << 2);
139 childregs
->cp0_status
= status
;
143 childregs
->regs
[7] = 0; /* Clear error flag */
144 childregs
->regs
[2] = 0; /* Child gets zero as return value */
146 childregs
->regs
[29] = usp
;
147 ti
->addr_limit
= USER_DS
;
149 p
->thread
.reg29
= (unsigned long) childregs
;
150 p
->thread
.reg31
= (unsigned long) ret_from_fork
;
153 * New tasks lose permission to use the fpu. This accelerates context
154 * switching for most programs since they don't use the fpu.
156 childregs
->cp0_status
&= ~(ST0_CU2
|ST0_CU1
);
158 clear_tsk_thread_flag(p
, TIF_USEDFPU
);
159 clear_tsk_thread_flag(p
, TIF_USEDMSA
);
160 clear_tsk_thread_flag(p
, TIF_MSA_CTX_LIVE
);
162 #ifdef CONFIG_MIPS_MT_FPAFF
163 clear_tsk_thread_flag(p
, TIF_FPUBOUND
);
164 #endif /* CONFIG_MIPS_MT_FPAFF */
166 if (clone_flags
& CLONE_SETTLS
)
167 ti
->tp_value
= regs
->regs
[7];
172 #ifdef CONFIG_CC_STACKPROTECTOR
173 #include <linux/stackprotector.h>
174 unsigned long __stack_chk_guard __read_mostly
;
175 EXPORT_SYMBOL(__stack_chk_guard
);
178 struct mips_frame_info
{
180 unsigned long func_size
;
185 #define J_TARGET(pc,target) \
186 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
188 static inline int is_ra_save_ins(union mips_instruction
*ip
)
190 #ifdef CONFIG_CPU_MICROMIPS
191 union mips_instruction mmi
;
195 * swm16 reglist,offset(sp)
196 * swm32 reglist,offset(sp)
198 * jradiussp - NOT SUPPORTED
200 * microMIPS is way more fun...
202 if (mm_insn_16bit(ip
->halfword
[0])) {
203 mmi
.word
= (ip
->halfword
[0] << 16);
204 return (mmi
.mm16_r5_format
.opcode
== mm_swsp16_op
&&
205 mmi
.mm16_r5_format
.rt
== 31) ||
206 (mmi
.mm16_m_format
.opcode
== mm_pool16c_op
&&
207 mmi
.mm16_m_format
.func
== mm_swm16_op
);
210 mmi
.halfword
[0] = ip
->halfword
[1];
211 mmi
.halfword
[1] = ip
->halfword
[0];
212 return (mmi
.mm_m_format
.opcode
== mm_pool32b_op
&&
213 mmi
.mm_m_format
.rd
> 9 &&
214 mmi
.mm_m_format
.base
== 29 &&
215 mmi
.mm_m_format
.func
== mm_swm32_func
) ||
216 (mmi
.i_format
.opcode
== mm_sw32_op
&&
217 mmi
.i_format
.rs
== 29 &&
218 mmi
.i_format
.rt
== 31);
221 /* sw / sd $ra, offset($sp) */
222 return (ip
->i_format
.opcode
== sw_op
|| ip
->i_format
.opcode
== sd_op
) &&
223 ip
->i_format
.rs
== 29 &&
224 ip
->i_format
.rt
== 31;
228 static inline int is_jump_ins(union mips_instruction
*ip
)
230 #ifdef CONFIG_CPU_MICROMIPS
232 * jr16,jrc,jalr16,jalr16
234 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
235 * jraddiusp - NOT SUPPORTED
237 * microMIPS is kind of more fun...
239 union mips_instruction mmi
;
241 mmi
.word
= (ip
->halfword
[0] << 16);
243 if ((mmi
.mm16_r5_format
.opcode
== mm_pool16c_op
&&
244 (mmi
.mm16_r5_format
.rt
& mm_jr16_op
) == mm_jr16_op
) ||
245 ip
->j_format
.opcode
== mm_jal32_op
)
247 if (ip
->r_format
.opcode
!= mm_pool32a_op
||
248 ip
->r_format
.func
!= mm_pool32axf_op
)
250 return ((ip
->u_format
.uimmediate
>> 6) & mm_jalr_op
) == mm_jalr_op
;
252 if (ip
->j_format
.opcode
== j_op
)
254 if (ip
->j_format
.opcode
== jal_op
)
256 if (ip
->r_format
.opcode
!= spec_op
)
258 return ip
->r_format
.func
== jalr_op
|| ip
->r_format
.func
== jr_op
;
262 static inline int is_sp_move_ins(union mips_instruction
*ip
)
264 #ifdef CONFIG_CPU_MICROMIPS
269 * jradiussp - NOT SUPPORTED
271 * microMIPS is not more fun...
273 if (mm_insn_16bit(ip
->halfword
[0])) {
274 union mips_instruction mmi
;
276 mmi
.word
= (ip
->halfword
[0] << 16);
277 return (mmi
.mm16_r3_format
.opcode
== mm_pool16d_op
&&
278 mmi
.mm16_r3_format
.simmediate
&& mm_addiusp_func
) ||
279 (mmi
.mm16_r5_format
.opcode
== mm_pool16d_op
&&
280 mmi
.mm16_r5_format
.rt
== 29);
282 return ip
->mm_i_format
.opcode
== mm_addiu32_op
&&
283 ip
->mm_i_format
.rt
== 29 && ip
->mm_i_format
.rs
== 29;
285 /* addiu/daddiu sp,sp,-imm */
286 if (ip
->i_format
.rs
!= 29 || ip
->i_format
.rt
!= 29)
288 if (ip
->i_format
.opcode
== addiu_op
|| ip
->i_format
.opcode
== daddiu_op
)
294 static int get_frame_info(struct mips_frame_info
*info
)
296 #ifdef CONFIG_CPU_MICROMIPS
297 union mips_instruction
*ip
= (void *) (((char *) info
->func
) - 1);
299 union mips_instruction
*ip
= info
->func
;
301 unsigned max_insns
= info
->func_size
/ sizeof(union mips_instruction
);
304 info
->pc_offset
= -1;
305 info
->frame_size
= 0;
311 max_insns
= 128U; /* unknown function size */
312 max_insns
= min(128U, max_insns
);
314 for (i
= 0; i
< max_insns
; i
++, ip
++) {
318 if (!info
->frame_size
) {
319 if (is_sp_move_ins(ip
))
321 #ifdef CONFIG_CPU_MICROMIPS
322 if (mm_insn_16bit(ip
->halfword
[0]))
326 if (ip
->halfword
[0] & mm_addiusp_func
)
328 tmp
= (((ip
->halfword
[0] >> 1) & 0x1ff) << 2);
329 info
->frame_size
= -(signed short)(tmp
| ((tmp
& 0x100) ? 0xfe00 : 0));
331 tmp
= (ip
->halfword
[0] >> 1);
332 info
->frame_size
= -(signed short)(tmp
& 0xf);
334 ip
= (void *) &ip
->halfword
[1];
338 info
->frame_size
= - ip
->i_format
.simmediate
;
342 if (info
->pc_offset
== -1 && is_ra_save_ins(ip
)) {
344 ip
->i_format
.simmediate
/ sizeof(long);
348 if (info
->frame_size
&& info
->pc_offset
>= 0) /* nested */
350 if (info
->pc_offset
< 0) /* leaf */
352 /* prologue seems boggus... */
357 static struct mips_frame_info schedule_mfi __read_mostly
;
359 #ifdef CONFIG_KALLSYMS
360 static unsigned long get___schedule_addr(void)
362 return kallsyms_lookup_name("__schedule");
365 static unsigned long get___schedule_addr(void)
367 union mips_instruction
*ip
= (void *)schedule
;
371 for (i
= 0; i
< max_insns
; i
++, ip
++) {
372 if (ip
->j_format
.opcode
== j_op
)
373 return J_TARGET(ip
, ip
->j_format
.target
);
379 static int __init
frame_info_init(void)
381 unsigned long size
= 0;
382 #ifdef CONFIG_KALLSYMS
387 addr
= get___schedule_addr();
389 addr
= (unsigned long)schedule
;
391 #ifdef CONFIG_KALLSYMS
392 kallsyms_lookup_size_offset(addr
, &size
, &ofs
);
394 schedule_mfi
.func
= (void *)addr
;
395 schedule_mfi
.func_size
= size
;
397 get_frame_info(&schedule_mfi
);
400 * Without schedule() frame info, result given by
401 * thread_saved_pc() and get_wchan() are not reliable.
403 if (schedule_mfi
.pc_offset
< 0)
404 printk("Can't analyze schedule() prologue at %p\n", schedule
);
409 arch_initcall(frame_info_init
);
412 * Return saved PC of a blocked thread.
414 unsigned long thread_saved_pc(struct task_struct
*tsk
)
416 struct thread_struct
*t
= &tsk
->thread
;
418 /* New born processes are a special case */
419 if (t
->reg31
== (unsigned long) ret_from_fork
)
421 if (schedule_mfi
.pc_offset
< 0)
423 return ((unsigned long *)t
->reg29
)[schedule_mfi
.pc_offset
];
427 #ifdef CONFIG_KALLSYMS
428 /* generic stack unwinding function */
429 unsigned long notrace
unwind_stack_by_address(unsigned long stack_page
,
434 struct mips_frame_info info
;
435 unsigned long size
, ofs
;
437 extern void ret_from_irq(void);
438 extern void ret_from_exception(void);
444 * If we reached the bottom of interrupt context,
445 * return saved pc in pt_regs.
447 if (pc
== (unsigned long)ret_from_irq
||
448 pc
== (unsigned long)ret_from_exception
) {
449 struct pt_regs
*regs
;
450 if (*sp
>= stack_page
&&
451 *sp
+ sizeof(*regs
) <= stack_page
+ THREAD_SIZE
- 32) {
452 regs
= (struct pt_regs
*)*sp
;
454 if (__kernel_text_address(pc
)) {
455 *sp
= regs
->regs
[29];
456 *ra
= regs
->regs
[31];
462 if (!kallsyms_lookup_size_offset(pc
, &size
, &ofs
))
465 * Return ra if an exception occurred at the first instruction
467 if (unlikely(ofs
== 0)) {
473 info
.func
= (void *)(pc
- ofs
);
474 info
.func_size
= ofs
; /* analyze from start to ofs */
475 leaf
= get_frame_info(&info
);
479 if (*sp
< stack_page
||
480 *sp
+ info
.frame_size
> stack_page
+ THREAD_SIZE
- 32)
485 * For some extreme cases, get_frame_info() can
486 * consider wrongly a nested function as a leaf
487 * one. In that cases avoid to return always the
490 pc
= pc
!= *ra
? *ra
: 0;
492 pc
= ((unsigned long *)(*sp
))[info
.pc_offset
];
494 *sp
+= info
.frame_size
;
496 return __kernel_text_address(pc
) ? pc
: 0;
498 EXPORT_SYMBOL(unwind_stack_by_address
);
500 /* used by show_backtrace() */
501 unsigned long unwind_stack(struct task_struct
*task
, unsigned long *sp
,
502 unsigned long pc
, unsigned long *ra
)
504 unsigned long stack_page
= (unsigned long)task_stack_page(task
);
505 return unwind_stack_by_address(stack_page
, sp
, pc
, ra
);
510 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
512 unsigned long get_wchan(struct task_struct
*task
)
514 unsigned long pc
= 0;
515 #ifdef CONFIG_KALLSYMS
517 unsigned long ra
= 0;
520 if (!task
|| task
== current
|| task
->state
== TASK_RUNNING
)
522 if (!task_stack_page(task
))
525 pc
= thread_saved_pc(task
);
527 #ifdef CONFIG_KALLSYMS
528 sp
= task
->thread
.reg29
+ schedule_mfi
.frame_size
;
530 while (in_sched_functions(pc
))
531 pc
= unwind_stack(task
, &sp
, pc
, &ra
);
539 * Don't forget that the stack pointer must be aligned on a 8 bytes
540 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
542 unsigned long arch_align_stack(unsigned long sp
)
544 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
545 sp
-= get_random_int() & ~PAGE_MASK
;
550 static void arch_dump_stack(void *info
)
552 struct pt_regs
*regs
;
554 regs
= get_irq_regs();
562 void arch_trigger_all_cpu_backtrace(bool include_self
)
564 smp_call_function(arch_dump_stack
, NULL
, 1);
567 int mips_get_process_fp_mode(struct task_struct
*task
)
571 if (!test_tsk_thread_flag(task
, TIF_32BIT_FPREGS
))
572 value
|= PR_FP_MODE_FR
;
573 if (test_tsk_thread_flag(task
, TIF_HYBRID_FPREGS
))
574 value
|= PR_FP_MODE_FRE
;
579 int mips_set_process_fp_mode(struct task_struct
*task
, unsigned int value
)
581 const unsigned int known_bits
= PR_FP_MODE_FR
| PR_FP_MODE_FRE
;
582 unsigned long switch_count
;
583 struct task_struct
*t
;
585 /* Check the value is valid */
586 if (value
& ~known_bits
)
589 /* Avoid inadvertently triggering emulation */
590 if ((value
& PR_FP_MODE_FR
) && cpu_has_fpu
&&
591 !(current_cpu_data
.fpu_id
& MIPS_FPIR_F64
))
593 if ((value
& PR_FP_MODE_FRE
) && cpu_has_fpu
&& !cpu_has_fre
)
596 /* FR = 0 not supported in MIPS R6 */
597 if (!(value
& PR_FP_MODE_FR
) && cpu_has_fpu
&& cpu_has_mips_r6
)
600 /* Save FP & vector context, then disable FPU & MSA */
601 if (task
->signal
== current
->signal
)
604 /* Prevent any threads from obtaining live FP context */
605 atomic_set(&task
->mm
->context
.fp_mode_switching
, 1);
606 smp_mb__after_atomic();
609 * If there are multiple online CPUs then wait until all threads whose
610 * FP mode is about to change have been context switched. This approach
611 * allows us to only worry about whether an FP mode switch is in
612 * progress when FP is first used in a tasks time slice. Pretty much all
613 * of the mode switch overhead can thus be confined to cases where mode
614 * switches are actually occuring. That is, to here. However for the
615 * thread performing the mode switch it may take a while...
617 if (num_online_cpus() > 1) {
618 spin_lock_irq(&task
->sighand
->siglock
);
620 for_each_thread(task
, t
) {
624 switch_count
= t
->nvcsw
+ t
->nivcsw
;
627 spin_unlock_irq(&task
->sighand
->siglock
);
629 spin_lock_irq(&task
->sighand
->siglock
);
630 } while ((t
->nvcsw
+ t
->nivcsw
) == switch_count
);
633 spin_unlock_irq(&task
->sighand
->siglock
);
637 * There are now no threads of the process with live FP context, so it
638 * is safe to proceed with the FP mode switch.
640 for_each_thread(task
, t
) {
641 /* Update desired FP register width */
642 if (value
& PR_FP_MODE_FR
) {
643 clear_tsk_thread_flag(t
, TIF_32BIT_FPREGS
);
645 set_tsk_thread_flag(t
, TIF_32BIT_FPREGS
);
646 clear_tsk_thread_flag(t
, TIF_MSA_CTX_LIVE
);
649 /* Update desired FP single layout */
650 if (value
& PR_FP_MODE_FRE
)
651 set_tsk_thread_flag(t
, TIF_HYBRID_FPREGS
);
653 clear_tsk_thread_flag(t
, TIF_HYBRID_FPREGS
);
656 /* Allow threads to use FP again */
657 atomic_set(&task
->mm
->context
.fp_mode_switching
, 0);