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>
33 #include <asm/dsemul.h>
38 #include <asm/pgtable.h>
39 #include <asm/mipsregs.h>
40 #include <asm/processor.h>
42 #include <linux/uaccess.h>
45 #include <asm/isadep.h>
47 #include <asm/stacktrace.h>
48 #include <asm/irq_regs.h>
50 #ifdef CONFIG_HOTPLUG_CPU
51 void arch_cpu_idle_dead(void)
53 /* What the heck is this check doing ? */
54 if (!cpumask_test_cpu(smp_processor_id(), &cpu_callin_map
))
59 asmlinkage
void ret_from_fork(void);
60 asmlinkage
void ret_from_kernel_thread(void);
62 void start_thread(struct pt_regs
* regs
, unsigned long pc
, unsigned long sp
)
66 /* New thread loses kernel privileges. */
67 status
= regs
->cp0_status
& ~(ST0_CU0
|ST0_CU1
|ST0_FR
|KU_MASK
);
69 regs
->cp0_status
= status
;
71 clear_thread_flag(TIF_MSA_CTX_LIVE
);
73 atomic_set(¤t
->thread
.bd_emu_frame
, BD_EMUFRAME_NONE
);
79 void exit_thread(struct task_struct
*tsk
)
82 * User threads may have allocated a delay slot emulation frame.
83 * If so, clean up that allocation.
85 if (!(current
->flags
& PF_KTHREAD
))
86 dsemul_thread_cleanup(tsk
);
89 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
92 * Save any process state which is live in hardware registers to the
93 * parent context prior to duplication. This prevents the new child
94 * state becoming stale if the parent is preempted before copy_thread()
95 * gets a chance to save the parent's live hardware registers to the
100 if (is_msa_enabled())
102 else if (is_fpu_owner())
114 * Copy architecture-specific thread state
116 int copy_thread(unsigned long clone_flags
, unsigned long usp
,
117 unsigned long kthread_arg
, struct task_struct
*p
)
119 struct thread_info
*ti
= task_thread_info(p
);
120 struct pt_regs
*childregs
, *regs
= current_pt_regs();
121 unsigned long childksp
;
122 p
->set_child_tid
= p
->clear_child_tid
= NULL
;
124 childksp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
- 32;
126 /* set up new TSS. */
127 childregs
= (struct pt_regs
*) childksp
- 1;
128 /* Put the stack after the struct pt_regs. */
129 childksp
= (unsigned long) childregs
;
130 p
->thread
.cp0_status
= read_c0_status() & ~(ST0_CU2
|ST0_CU1
);
131 if (unlikely(p
->flags
& PF_KTHREAD
)) {
133 unsigned long status
= p
->thread
.cp0_status
;
134 memset(childregs
, 0, sizeof(struct pt_regs
));
135 ti
->addr_limit
= KERNEL_DS
;
136 p
->thread
.reg16
= usp
; /* fn */
137 p
->thread
.reg17
= kthread_arg
;
138 p
->thread
.reg29
= childksp
;
139 p
->thread
.reg31
= (unsigned long) ret_from_kernel_thread
;
140 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
141 status
= (status
& ~(ST0_KUP
| ST0_IEP
| ST0_IEC
)) |
142 ((status
& (ST0_KUC
| ST0_IEC
)) << 2);
146 childregs
->cp0_status
= status
;
152 childregs
->regs
[7] = 0; /* Clear error flag */
153 childregs
->regs
[2] = 0; /* Child gets zero as return value */
155 childregs
->regs
[29] = usp
;
156 ti
->addr_limit
= USER_DS
;
158 p
->thread
.reg29
= (unsigned long) childregs
;
159 p
->thread
.reg31
= (unsigned long) ret_from_fork
;
162 * New tasks lose permission to use the fpu. This accelerates context
163 * switching for most programs since they don't use the fpu.
165 childregs
->cp0_status
&= ~(ST0_CU2
|ST0_CU1
);
167 clear_tsk_thread_flag(p
, TIF_USEDFPU
);
168 clear_tsk_thread_flag(p
, TIF_USEDMSA
);
169 clear_tsk_thread_flag(p
, TIF_MSA_CTX_LIVE
);
171 #ifdef CONFIG_MIPS_MT_FPAFF
172 clear_tsk_thread_flag(p
, TIF_FPUBOUND
);
173 #endif /* CONFIG_MIPS_MT_FPAFF */
175 atomic_set(&p
->thread
.bd_emu_frame
, BD_EMUFRAME_NONE
);
177 if (clone_flags
& CLONE_SETTLS
)
178 ti
->tp_value
= regs
->regs
[7];
183 #ifdef CONFIG_CC_STACKPROTECTOR
184 #include <linux/stackprotector.h>
185 unsigned long __stack_chk_guard __read_mostly
;
186 EXPORT_SYMBOL(__stack_chk_guard
);
189 struct mips_frame_info
{
191 unsigned long func_size
;
196 #define J_TARGET(pc,target) \
197 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
199 static inline int is_ra_save_ins(union mips_instruction
*ip
)
201 #ifdef CONFIG_CPU_MICROMIPS
204 * swm16 reglist,offset(sp)
205 * swm32 reglist,offset(sp)
207 * jradiussp - NOT SUPPORTED
209 * microMIPS is way more fun...
211 if (mm_insn_16bit(ip
->halfword
[1])) {
212 return (ip
->mm16_r5_format
.opcode
== mm_swsp16_op
&&
213 ip
->mm16_r5_format
.rt
== 31) ||
214 (ip
->mm16_m_format
.opcode
== mm_pool16c_op
&&
215 ip
->mm16_m_format
.func
== mm_swm16_op
);
218 return (ip
->mm_m_format
.opcode
== mm_pool32b_op
&&
219 ip
->mm_m_format
.rd
> 9 &&
220 ip
->mm_m_format
.base
== 29 &&
221 ip
->mm_m_format
.func
== mm_swm32_func
) ||
222 (ip
->i_format
.opcode
== mm_sw32_op
&&
223 ip
->i_format
.rs
== 29 &&
224 ip
->i_format
.rt
== 31);
227 /* sw / sd $ra, offset($sp) */
228 return (ip
->i_format
.opcode
== sw_op
|| ip
->i_format
.opcode
== sd_op
) &&
229 ip
->i_format
.rs
== 29 &&
230 ip
->i_format
.rt
== 31;
234 static inline int is_jump_ins(union mips_instruction
*ip
)
236 #ifdef CONFIG_CPU_MICROMIPS
238 * jr16,jrc,jalr16,jalr16
240 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
241 * jraddiusp - NOT SUPPORTED
243 * microMIPS is kind of more fun...
245 if (mm_insn_16bit(ip
->halfword
[1])) {
246 if ((ip
->mm16_r5_format
.opcode
== mm_pool16c_op
&&
247 (ip
->mm16_r5_format
.rt
& mm_jr16_op
) == mm_jr16_op
))
252 if (ip
->j_format
.opcode
== mm_jal32_op
)
254 if (ip
->r_format
.opcode
!= mm_pool32a_op
||
255 ip
->r_format
.func
!= mm_pool32axf_op
)
257 return ((ip
->u_format
.uimmediate
>> 6) & mm_jalr_op
) == mm_jalr_op
;
259 if (ip
->j_format
.opcode
== j_op
)
261 if (ip
->j_format
.opcode
== jal_op
)
263 if (ip
->r_format
.opcode
!= spec_op
)
265 return ip
->r_format
.func
== jalr_op
|| ip
->r_format
.func
== jr_op
;
269 static inline int is_sp_move_ins(union mips_instruction
*ip
)
271 #ifdef CONFIG_CPU_MICROMIPS
276 * jradiussp - NOT SUPPORTED
278 * microMIPS is not more fun...
280 if (mm_insn_16bit(ip
->halfword
[1])) {
281 return (ip
->mm16_r3_format
.opcode
== mm_pool16d_op
&&
282 ip
->mm16_r3_format
.simmediate
&& mm_addiusp_func
) ||
283 (ip
->mm16_r5_format
.opcode
== mm_pool16d_op
&&
284 ip
->mm16_r5_format
.rt
== 29);
287 return ip
->mm_i_format
.opcode
== mm_addiu32_op
&&
288 ip
->mm_i_format
.rt
== 29 && ip
->mm_i_format
.rs
== 29;
290 /* addiu/daddiu sp,sp,-imm */
291 if (ip
->i_format
.rs
!= 29 || ip
->i_format
.rt
!= 29)
293 if (ip
->i_format
.opcode
== addiu_op
|| ip
->i_format
.opcode
== daddiu_op
)
299 static int get_frame_info(struct mips_frame_info
*info
)
301 bool is_mmips
= IS_ENABLED(CONFIG_CPU_MICROMIPS
);
302 union mips_instruction insn
, *ip
, *ip_end
;
303 const unsigned int max_insns
= 128;
306 info
->pc_offset
= -1;
307 info
->frame_size
= 0;
309 ip
= (void *)msk_isa16_mode((ulong
)info
->func
);
313 ip_end
= (void *)ip
+ info
->func_size
;
315 for (i
= 0; i
< max_insns
&& ip
< ip_end
; i
++, ip
++) {
316 if (is_mmips
&& mm_insn_16bit(ip
->halfword
[0])) {
317 insn
.halfword
[0] = 0;
318 insn
.halfword
[1] = ip
->halfword
[0];
319 } else if (is_mmips
) {
320 insn
.halfword
[0] = ip
->halfword
[1];
321 insn
.halfword
[1] = ip
->halfword
[0];
323 insn
.word
= ip
->word
;
326 if (is_jump_ins(&insn
))
329 if (!info
->frame_size
) {
330 if (is_sp_move_ins(&insn
))
332 #ifdef CONFIG_CPU_MICROMIPS
333 if (mm_insn_16bit(ip
->halfword
[0]))
337 if (ip
->halfword
[0] & mm_addiusp_func
)
339 tmp
= (((ip
->halfword
[0] >> 1) & 0x1ff) << 2);
340 info
->frame_size
= -(signed short)(tmp
| ((tmp
& 0x100) ? 0xfe00 : 0));
342 tmp
= (ip
->halfword
[0] >> 1);
343 info
->frame_size
= -(signed short)(tmp
& 0xf);
345 ip
= (void *) &ip
->halfword
[1];
349 info
->frame_size
= - ip
->i_format
.simmediate
;
353 if (info
->pc_offset
== -1 && is_ra_save_ins(&insn
)) {
355 ip
->i_format
.simmediate
/ sizeof(long);
359 if (info
->frame_size
&& info
->pc_offset
>= 0) /* nested */
361 if (info
->pc_offset
< 0) /* leaf */
363 /* prologue seems bogus... */
368 static struct mips_frame_info schedule_mfi __read_mostly
;
370 #ifdef CONFIG_KALLSYMS
371 static unsigned long get___schedule_addr(void)
373 return kallsyms_lookup_name("__schedule");
376 static unsigned long get___schedule_addr(void)
378 union mips_instruction
*ip
= (void *)schedule
;
382 for (i
= 0; i
< max_insns
; i
++, ip
++) {
383 if (ip
->j_format
.opcode
== j_op
)
384 return J_TARGET(ip
, ip
->j_format
.target
);
390 static int __init
frame_info_init(void)
392 unsigned long size
= 0;
393 #ifdef CONFIG_KALLSYMS
398 addr
= get___schedule_addr();
400 addr
= (unsigned long)schedule
;
402 #ifdef CONFIG_KALLSYMS
403 kallsyms_lookup_size_offset(addr
, &size
, &ofs
);
405 schedule_mfi
.func
= (void *)addr
;
406 schedule_mfi
.func_size
= size
;
408 get_frame_info(&schedule_mfi
);
411 * Without schedule() frame info, result given by
412 * thread_saved_pc() and get_wchan() are not reliable.
414 if (schedule_mfi
.pc_offset
< 0)
415 printk("Can't analyze schedule() prologue at %p\n", schedule
);
420 arch_initcall(frame_info_init
);
423 * Return saved PC of a blocked thread.
425 unsigned long thread_saved_pc(struct task_struct
*tsk
)
427 struct thread_struct
*t
= &tsk
->thread
;
429 /* New born processes are a special case */
430 if (t
->reg31
== (unsigned long) ret_from_fork
)
432 if (schedule_mfi
.pc_offset
< 0)
434 return ((unsigned long *)t
->reg29
)[schedule_mfi
.pc_offset
];
438 #ifdef CONFIG_KALLSYMS
439 /* generic stack unwinding function */
440 unsigned long notrace
unwind_stack_by_address(unsigned long stack_page
,
445 struct mips_frame_info info
;
446 unsigned long size
, ofs
;
448 extern void ret_from_irq(void);
449 extern void ret_from_exception(void);
455 * If we reached the bottom of interrupt context,
456 * return saved pc in pt_regs.
458 if (pc
== (unsigned long)ret_from_irq
||
459 pc
== (unsigned long)ret_from_exception
) {
460 struct pt_regs
*regs
;
461 if (*sp
>= stack_page
&&
462 *sp
+ sizeof(*regs
) <= stack_page
+ THREAD_SIZE
- 32) {
463 regs
= (struct pt_regs
*)*sp
;
465 if (!user_mode(regs
) && __kernel_text_address(pc
)) {
466 *sp
= regs
->regs
[29];
467 *ra
= regs
->regs
[31];
473 if (!kallsyms_lookup_size_offset(pc
, &size
, &ofs
))
476 * Return ra if an exception occurred at the first instruction
478 if (unlikely(ofs
== 0)) {
484 info
.func
= (void *)(pc
- ofs
);
485 info
.func_size
= ofs
; /* analyze from start to ofs */
486 leaf
= get_frame_info(&info
);
490 if (*sp
< stack_page
||
491 *sp
+ info
.frame_size
> stack_page
+ THREAD_SIZE
- 32)
496 * For some extreme cases, get_frame_info() can
497 * consider wrongly a nested function as a leaf
498 * one. In that cases avoid to return always the
501 pc
= pc
!= *ra
? *ra
: 0;
503 pc
= ((unsigned long *)(*sp
))[info
.pc_offset
];
505 *sp
+= info
.frame_size
;
507 return __kernel_text_address(pc
) ? pc
: 0;
509 EXPORT_SYMBOL(unwind_stack_by_address
);
511 /* used by show_backtrace() */
512 unsigned long unwind_stack(struct task_struct
*task
, unsigned long *sp
,
513 unsigned long pc
, unsigned long *ra
)
515 unsigned long stack_page
= 0;
518 for_each_possible_cpu(cpu
) {
519 if (on_irq_stack(cpu
, *sp
)) {
520 stack_page
= (unsigned long)irq_stack
[cpu
];
526 stack_page
= (unsigned long)task_stack_page(task
);
528 return unwind_stack_by_address(stack_page
, sp
, pc
, ra
);
533 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
535 unsigned long get_wchan(struct task_struct
*task
)
537 unsigned long pc
= 0;
538 #ifdef CONFIG_KALLSYMS
540 unsigned long ra
= 0;
543 if (!task
|| task
== current
|| task
->state
== TASK_RUNNING
)
545 if (!task_stack_page(task
))
548 pc
= thread_saved_pc(task
);
550 #ifdef CONFIG_KALLSYMS
551 sp
= task
->thread
.reg29
+ schedule_mfi
.frame_size
;
553 while (in_sched_functions(pc
))
554 pc
= unwind_stack(task
, &sp
, pc
, &ra
);
562 * Don't forget that the stack pointer must be aligned on a 8 bytes
563 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
565 unsigned long arch_align_stack(unsigned long sp
)
567 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
568 sp
-= get_random_int() & ~PAGE_MASK
;
573 static void arch_dump_stack(void *info
)
575 struct pt_regs
*regs
;
577 regs
= get_irq_regs();
585 void arch_trigger_cpumask_backtrace(const cpumask_t
*mask
, bool exclude_self
)
587 long this_cpu
= get_cpu();
589 if (cpumask_test_cpu(this_cpu
, mask
) && !exclude_self
)
592 smp_call_function_many(mask
, arch_dump_stack
, NULL
, 1);
597 int mips_get_process_fp_mode(struct task_struct
*task
)
601 if (!test_tsk_thread_flag(task
, TIF_32BIT_FPREGS
))
602 value
|= PR_FP_MODE_FR
;
603 if (test_tsk_thread_flag(task
, TIF_HYBRID_FPREGS
))
604 value
|= PR_FP_MODE_FRE
;
609 static void prepare_for_fp_mode_switch(void *info
)
611 struct mm_struct
*mm
= info
;
613 if (current
->mm
== mm
)
617 int mips_set_process_fp_mode(struct task_struct
*task
, unsigned int value
)
619 const unsigned int known_bits
= PR_FP_MODE_FR
| PR_FP_MODE_FRE
;
620 struct task_struct
*t
;
623 /* Check the value is valid */
624 if (value
& ~known_bits
)
627 /* Avoid inadvertently triggering emulation */
628 if ((value
& PR_FP_MODE_FR
) && raw_cpu_has_fpu
&&
629 !(raw_current_cpu_data
.fpu_id
& MIPS_FPIR_F64
))
631 if ((value
& PR_FP_MODE_FRE
) && raw_cpu_has_fpu
&& !cpu_has_fre
)
634 /* FR = 0 not supported in MIPS R6 */
635 if (!(value
& PR_FP_MODE_FR
) && raw_cpu_has_fpu
&& cpu_has_mips_r6
)
638 /* Proceed with the mode switch */
641 /* Save FP & vector context, then disable FPU & MSA */
642 if (task
->signal
== current
->signal
)
645 /* Prevent any threads from obtaining live FP context */
646 atomic_set(&task
->mm
->context
.fp_mode_switching
, 1);
647 smp_mb__after_atomic();
650 * If there are multiple online CPUs then force any which are running
651 * threads in this process to lose their FPU context, which they can't
652 * regain until fp_mode_switching is cleared later.
654 if (num_online_cpus() > 1) {
655 /* No need to send an IPI for the local CPU */
656 max_users
= (task
->mm
== current
->mm
) ? 1 : 0;
658 if (atomic_read(¤t
->mm
->mm_users
) > max_users
)
659 smp_call_function(prepare_for_fp_mode_switch
,
660 (void *)current
->mm
, 1);
664 * There are now no threads of the process with live FP context, so it
665 * is safe to proceed with the FP mode switch.
667 for_each_thread(task
, t
) {
668 /* Update desired FP register width */
669 if (value
& PR_FP_MODE_FR
) {
670 clear_tsk_thread_flag(t
, TIF_32BIT_FPREGS
);
672 set_tsk_thread_flag(t
, TIF_32BIT_FPREGS
);
673 clear_tsk_thread_flag(t
, TIF_MSA_CTX_LIVE
);
676 /* Update desired FP single layout */
677 if (value
& PR_FP_MODE_FRE
)
678 set_tsk_thread_flag(t
, TIF_HYBRID_FPREGS
);
680 clear_tsk_thread_flag(t
, TIF_HYBRID_FPREGS
);
683 /* Allow threads to use FP again */
684 atomic_set(&task
->mm
->context
.fp_mode_switching
, 0);