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/sched/debug.h>
15 #include <linux/sched/task.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/tick.h>
18 #include <linux/kernel.h>
20 #include <linux/stddef.h>
21 #include <linux/unistd.h>
22 #include <linux/export.h>
23 #include <linux/ptrace.h>
24 #include <linux/mman.h>
25 #include <linux/personality.h>
26 #include <linux/sys.h>
27 #include <linux/init.h>
28 #include <linux/completion.h>
29 #include <linux/kallsyms.h>
30 #include <linux/random.h>
31 #include <linux/prctl.h>
34 #include <asm/bootinfo.h>
36 #include <asm/dsemul.h>
41 #include <asm/pgtable.h>
42 #include <asm/mipsregs.h>
43 #include <asm/processor.h>
45 #include <linux/uaccess.h>
48 #include <asm/isadep.h>
50 #include <asm/stacktrace.h>
51 #include <asm/irq_regs.h>
53 #ifdef CONFIG_HOTPLUG_CPU
54 void arch_cpu_idle_dead(void)
60 asmlinkage void ret_from_fork(void);
61 asmlinkage void ret_from_kernel_thread(void);
63 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
67 /* New thread loses kernel privileges. */
68 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
70 regs->cp0_status = status;
72 clear_thread_flag(TIF_MSA_CTX_LIVE);
74 atomic_set(¤t->thread.bd_emu_frame, BD_EMUFRAME_NONE);
80 void exit_thread(struct task_struct *tsk)
83 * User threads may have allocated a delay slot emulation frame.
84 * If so, clean up that allocation.
86 if (!(current->flags & PF_KTHREAD))
87 dsemul_thread_cleanup(tsk);
90 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
93 * Save any process state which is live in hardware registers to the
94 * parent context prior to duplication. This prevents the new child
95 * state becoming stale if the parent is preempted before copy_thread()
96 * gets a chance to save the parent's live hardware registers to the
101 if (is_msa_enabled())
103 else if (is_fpu_owner())
115 * Copy architecture-specific thread state
117 int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
118 unsigned long kthread_arg, struct task_struct *p, unsigned long tls)
120 struct thread_info *ti = task_thread_info(p);
121 struct pt_regs *childregs, *regs = current_pt_regs();
122 unsigned long childksp;
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)
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, int *poff)
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 switch (ip->mm16_r5_format.opcode) {
214 if (ip->mm16_r5_format.rt != 31)
217 *poff = ip->mm16_r5_format.simmediate;
218 *poff = (*poff << 2) / sizeof(ulong);
222 switch (ip->mm16_m_format.func) {
224 *poff = ip->mm16_m_format.imm;
225 *poff += 1 + ip->mm16_m_format.rlist;
226 *poff = (*poff << 2) / sizeof(ulong);
238 switch (ip->i_format.opcode) {
240 if (ip->i_format.rs != 29)
242 if (ip->i_format.rt != 31)
245 *poff = ip->i_format.simmediate / sizeof(ulong);
249 switch (ip->mm_m_format.func) {
251 if (ip->mm_m_format.rd < 0x10)
253 if (ip->mm_m_format.base != 29)
256 *poff = ip->mm_m_format.simmediate;
257 *poff += (ip->mm_m_format.rd & 0xf) * sizeof(u32);
258 *poff /= sizeof(ulong);
268 /* sw / sd $ra, offset($sp) */
269 if ((ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
270 ip->i_format.rs == 29 && ip->i_format.rt == 31) {
271 *poff = ip->i_format.simmediate / sizeof(ulong);
279 static inline int is_jump_ins(union mips_instruction *ip)
281 #ifdef CONFIG_CPU_MICROMIPS
283 * jr16,jrc,jalr16,jalr16
285 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
286 * jraddiusp - NOT SUPPORTED
288 * microMIPS is kind of more fun...
290 if (mm_insn_16bit(ip->halfword[1])) {
291 if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
292 (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
297 if (ip->j_format.opcode == mm_j32_op)
299 if (ip->j_format.opcode == mm_jal32_op)
301 if (ip->r_format.opcode != mm_pool32a_op ||
302 ip->r_format.func != mm_pool32axf_op)
304 return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
306 if (ip->j_format.opcode == j_op)
308 if (ip->j_format.opcode == jal_op)
310 if (ip->r_format.opcode != spec_op)
312 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
316 static inline int is_sp_move_ins(union mips_instruction *ip)
318 #ifdef CONFIG_CPU_MICROMIPS
323 * jradiussp - NOT SUPPORTED
325 * microMIPS is not more fun...
327 if (mm_insn_16bit(ip->halfword[1])) {
328 return (ip->mm16_r3_format.opcode == mm_pool16d_op &&
329 ip->mm16_r3_format.simmediate && mm_addiusp_func) ||
330 (ip->mm16_r5_format.opcode == mm_pool16d_op &&
331 ip->mm16_r5_format.rt == 29);
334 return ip->mm_i_format.opcode == mm_addiu32_op &&
335 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
337 /* addiu/daddiu sp,sp,-imm */
338 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
340 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
346 static int get_frame_info(struct mips_frame_info *info)
348 bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
349 union mips_instruction insn, *ip, *ip_end;
350 const unsigned int max_insns = 128;
353 info->pc_offset = -1;
354 info->frame_size = 0;
356 ip = (void *)msk_isa16_mode((ulong)info->func);
360 ip_end = (void *)ip + info->func_size;
362 for (i = 0; i < max_insns && ip < ip_end; i++, ip++) {
363 if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
364 insn.halfword[0] = 0;
365 insn.halfword[1] = ip->halfword[0];
366 } else if (is_mmips) {
367 insn.halfword[0] = ip->halfword[1];
368 insn.halfword[1] = ip->halfword[0];
370 insn.word = ip->word;
373 if (is_jump_ins(&insn))
376 if (!info->frame_size) {
377 if (is_sp_move_ins(&insn))
379 #ifdef CONFIG_CPU_MICROMIPS
380 if (mm_insn_16bit(ip->halfword[0]))
384 if (ip->halfword[0] & mm_addiusp_func)
386 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
387 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
389 tmp = (ip->halfword[0] >> 1);
390 info->frame_size = -(signed short)(tmp & 0xf);
392 ip = (void *) &ip->halfword[1];
396 info->frame_size = - ip->i_format.simmediate;
400 if (info->pc_offset == -1 &&
401 is_ra_save_ins(&insn, &info->pc_offset))
404 if (info->frame_size && info->pc_offset >= 0) /* nested */
406 if (info->pc_offset < 0) /* leaf */
408 /* prologue seems bogus... */
413 static struct mips_frame_info schedule_mfi __read_mostly;
415 #ifdef CONFIG_KALLSYMS
416 static unsigned long get___schedule_addr(void)
418 return kallsyms_lookup_name("__schedule");
421 static unsigned long get___schedule_addr(void)
423 union mips_instruction *ip = (void *)schedule;
427 for (i = 0; i < max_insns; i++, ip++) {
428 if (ip->j_format.opcode == j_op)
429 return J_TARGET(ip, ip->j_format.target);
435 static int __init frame_info_init(void)
437 unsigned long size = 0;
438 #ifdef CONFIG_KALLSYMS
443 addr = get___schedule_addr();
445 addr = (unsigned long)schedule;
447 #ifdef CONFIG_KALLSYMS
448 kallsyms_lookup_size_offset(addr, &size, &ofs);
450 schedule_mfi.func = (void *)addr;
451 schedule_mfi.func_size = size;
453 get_frame_info(&schedule_mfi);
456 * Without schedule() frame info, result given by
457 * thread_saved_pc() and get_wchan() are not reliable.
459 if (schedule_mfi.pc_offset < 0)
460 printk("Can't analyze schedule() prologue at %p\n", schedule);
465 arch_initcall(frame_info_init);
468 * Return saved PC of a blocked thread.
470 unsigned long thread_saved_pc(struct task_struct *tsk)
472 struct thread_struct *t = &tsk->thread;
474 /* New born processes are a special case */
475 if (t->reg31 == (unsigned long) ret_from_fork)
477 if (schedule_mfi.pc_offset < 0)
479 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
483 #ifdef CONFIG_KALLSYMS
484 /* generic stack unwinding function */
485 unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
490 unsigned long low, high, irq_stack_high;
491 struct mips_frame_info info;
492 unsigned long size, ofs;
493 struct pt_regs *regs;
500 * IRQ stacks start at IRQ_STACK_START
501 * task stacks at THREAD_SIZE - 32
504 if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) {
505 high = stack_page + IRQ_STACK_START;
506 irq_stack_high = high;
508 high = stack_page + THREAD_SIZE - 32;
513 * If we reached the top of the interrupt stack, start unwinding
514 * the interrupted task stack.
516 if (unlikely(*sp == irq_stack_high)) {
517 unsigned long task_sp = *(unsigned long *)*sp;
520 * Check that the pointer saved in the IRQ stack head points to
521 * something within the stack of the current task
523 if (!object_is_on_stack((void *)task_sp))
527 * Follow pointer to tasks kernel stack frame where interrupted
530 regs = (struct pt_regs *)task_sp;
532 if (!user_mode(regs) && __kernel_text_address(pc)) {
533 *sp = regs->regs[29];
534 *ra = regs->regs[31];
539 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
542 * Return ra if an exception occurred at the first instruction
544 if (unlikely(ofs == 0)) {
550 info.func = (void *)(pc - ofs);
551 info.func_size = ofs; /* analyze from start to ofs */
552 leaf = get_frame_info(&info);
556 if (*sp < low || *sp + info.frame_size > high)
561 * For some extreme cases, get_frame_info() can
562 * consider wrongly a nested function as a leaf
563 * one. In that cases avoid to return always the
566 pc = pc != *ra ? *ra : 0;
568 pc = ((unsigned long *)(*sp))[info.pc_offset];
570 *sp += info.frame_size;
572 return __kernel_text_address(pc) ? pc : 0;
574 EXPORT_SYMBOL(unwind_stack_by_address);
576 /* used by show_backtrace() */
577 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
578 unsigned long pc, unsigned long *ra)
580 unsigned long stack_page = 0;
583 for_each_possible_cpu(cpu) {
584 if (on_irq_stack(cpu, *sp)) {
585 stack_page = (unsigned long)irq_stack[cpu];
591 stack_page = (unsigned long)task_stack_page(task);
593 return unwind_stack_by_address(stack_page, sp, pc, ra);
598 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
600 unsigned long get_wchan(struct task_struct *task)
602 unsigned long pc = 0;
603 #ifdef CONFIG_KALLSYMS
605 unsigned long ra = 0;
608 if (!task || task == current || task->state == TASK_RUNNING)
610 if (!task_stack_page(task))
613 pc = thread_saved_pc(task);
615 #ifdef CONFIG_KALLSYMS
616 sp = task->thread.reg29 + schedule_mfi.frame_size;
618 while (in_sched_functions(pc))
619 pc = unwind_stack(task, &sp, pc, &ra);
627 * Don't forget that the stack pointer must be aligned on a 8 bytes
628 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
630 unsigned long arch_align_stack(unsigned long sp)
632 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
633 sp -= get_random_int() & ~PAGE_MASK;
638 static void arch_dump_stack(void *info)
640 struct pt_regs *regs;
642 regs = get_irq_regs();
650 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
652 long this_cpu = get_cpu();
654 if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
657 smp_call_function_many(mask, arch_dump_stack, NULL, 1);
662 int mips_get_process_fp_mode(struct task_struct *task)
666 if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
667 value |= PR_FP_MODE_FR;
668 if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
669 value |= PR_FP_MODE_FRE;
674 static void prepare_for_fp_mode_switch(void *info)
676 struct mm_struct *mm = info;
678 if (current->mm == mm)
682 int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
684 const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
685 struct task_struct *t;
688 /* Check the value is valid */
689 if (value & ~known_bits)
692 /* Avoid inadvertently triggering emulation */
693 if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu &&
694 !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64))
696 if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre)
699 /* FR = 0 not supported in MIPS R6 */
700 if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6)
703 /* Proceed with the mode switch */
706 /* Save FP & vector context, then disable FPU & MSA */
707 if (task->signal == current->signal)
710 /* Prevent any threads from obtaining live FP context */
711 atomic_set(&task->mm->context.fp_mode_switching, 1);
712 smp_mb__after_atomic();
715 * If there are multiple online CPUs then force any which are running
716 * threads in this process to lose their FPU context, which they can't
717 * regain until fp_mode_switching is cleared later.
719 if (num_online_cpus() > 1) {
720 /* No need to send an IPI for the local CPU */
721 max_users = (task->mm == current->mm) ? 1 : 0;
723 if (atomic_read(¤t->mm->mm_users) > max_users)
724 smp_call_function(prepare_for_fp_mode_switch,
725 (void *)current->mm, 1);
729 * There are now no threads of the process with live FP context, so it
730 * is safe to proceed with the FP mode switch.
732 for_each_thread(task, t) {
733 /* Update desired FP register width */
734 if (value & PR_FP_MODE_FR) {
735 clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
737 set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
738 clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
741 /* Update desired FP single layout */
742 if (value & PR_FP_MODE_FRE)
743 set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
745 clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
748 /* Allow threads to use FP again */
749 atomic_set(&task->mm->context.fp_mode_switching, 0);
755 #if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
756 void mips_dump_regs32(u32 *uregs, const struct pt_regs *regs)
760 for (i = MIPS32_EF_R1; i <= MIPS32_EF_R31; i++) {
761 /* k0/k1 are copied as zero. */
762 if (i == MIPS32_EF_R26 || i == MIPS32_EF_R27)
765 uregs[i] = regs->regs[i - MIPS32_EF_R0];
768 uregs[MIPS32_EF_LO] = regs->lo;
769 uregs[MIPS32_EF_HI] = regs->hi;
770 uregs[MIPS32_EF_CP0_EPC] = regs->cp0_epc;
771 uregs[MIPS32_EF_CP0_BADVADDR] = regs->cp0_badvaddr;
772 uregs[MIPS32_EF_CP0_STATUS] = regs->cp0_status;
773 uregs[MIPS32_EF_CP0_CAUSE] = regs->cp0_cause;
775 #endif /* CONFIG_32BIT || CONFIG_MIPS32_O32 */
778 void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs)
782 for (i = MIPS64_EF_R1; i <= MIPS64_EF_R31; i++) {
783 /* k0/k1 are copied as zero. */
784 if (i == MIPS64_EF_R26 || i == MIPS64_EF_R27)
787 uregs[i] = regs->regs[i - MIPS64_EF_R0];
790 uregs[MIPS64_EF_LO] = regs->lo;
791 uregs[MIPS64_EF_HI] = regs->hi;
792 uregs[MIPS64_EF_CP0_EPC] = regs->cp0_epc;
793 uregs[MIPS64_EF_CP0_BADVADDR] = regs->cp0_badvaddr;
794 uregs[MIPS64_EF_CP0_STATUS] = regs->cp0_status;
795 uregs[MIPS64_EF_CP0_CAUSE] = regs->cp0_cause;
797 #endif /* CONFIG_64BIT */