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 (!cpumask_test_cpu(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())
111 * Copy architecture-specific thread state
113 int copy_thread(unsigned long clone_flags, unsigned long usp,
114 unsigned long kthread_arg, struct task_struct *p)
116 struct thread_info *ti = task_thread_info(p);
117 struct pt_regs *childregs, *regs = current_pt_regs();
118 unsigned long childksp;
119 p->set_child_tid = p->clear_child_tid = NULL;
121 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
123 /* set up new TSS. */
124 childregs = (struct pt_regs *) childksp - 1;
125 /* Put the stack after the struct pt_regs. */
126 childksp = (unsigned long) childregs;
127 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
128 if (unlikely(p->flags & PF_KTHREAD)) {
130 unsigned long status = p->thread.cp0_status;
131 memset(childregs, 0, sizeof(struct pt_regs));
132 ti->addr_limit = KERNEL_DS;
133 p->thread.reg16 = usp; /* fn */
134 p->thread.reg17 = kthread_arg;
135 p->thread.reg29 = childksp;
136 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
137 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
138 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
139 ((status & (ST0_KUC | ST0_IEC)) << 2);
143 childregs->cp0_status = status;
149 childregs->regs[7] = 0; /* Clear error flag */
150 childregs->regs[2] = 0; /* Child gets zero as return value */
152 childregs->regs[29] = usp;
153 ti->addr_limit = USER_DS;
155 p->thread.reg29 = (unsigned long) childregs;
156 p->thread.reg31 = (unsigned long) ret_from_fork;
159 * New tasks lose permission to use the fpu. This accelerates context
160 * switching for most programs since they don't use the fpu.
162 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
164 clear_tsk_thread_flag(p, TIF_USEDFPU);
165 clear_tsk_thread_flag(p, TIF_USEDMSA);
166 clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
168 #ifdef CONFIG_MIPS_MT_FPAFF
169 clear_tsk_thread_flag(p, TIF_FPUBOUND);
170 #endif /* CONFIG_MIPS_MT_FPAFF */
172 if (clone_flags & CLONE_SETTLS)
173 ti->tp_value = regs->regs[7];
178 #ifdef CONFIG_CC_STACKPROTECTOR
179 #include <linux/stackprotector.h>
180 unsigned long __stack_chk_guard __read_mostly;
181 EXPORT_SYMBOL(__stack_chk_guard);
184 struct mips_frame_info {
186 unsigned long func_size;
191 #define J_TARGET(pc,target) \
192 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
194 static inline int is_ra_save_ins(union mips_instruction *ip)
196 #ifdef CONFIG_CPU_MICROMIPS
197 union mips_instruction mmi;
201 * swm16 reglist,offset(sp)
202 * swm32 reglist,offset(sp)
204 * jradiussp - NOT SUPPORTED
206 * microMIPS is way more fun...
208 if (mm_insn_16bit(ip->halfword[0])) {
209 mmi.word = (ip->halfword[0] << 16);
210 return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
211 mmi.mm16_r5_format.rt == 31) ||
212 (mmi.mm16_m_format.opcode == mm_pool16c_op &&
213 mmi.mm16_m_format.func == mm_swm16_op);
216 mmi.halfword[0] = ip->halfword[1];
217 mmi.halfword[1] = ip->halfword[0];
218 return (mmi.mm_m_format.opcode == mm_pool32b_op &&
219 mmi.mm_m_format.rd > 9 &&
220 mmi.mm_m_format.base == 29 &&
221 mmi.mm_m_format.func == mm_swm32_func) ||
222 (mmi.i_format.opcode == mm_sw32_op &&
223 mmi.i_format.rs == 29 &&
224 mmi.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 union mips_instruction mmi;
247 mmi.word = (ip->halfword[0] << 16);
249 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
250 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
251 ip->j_format.opcode == mm_jal32_op)
253 if (ip->r_format.opcode != mm_pool32a_op ||
254 ip->r_format.func != mm_pool32axf_op)
256 return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
258 if (ip->j_format.opcode == j_op)
260 if (ip->j_format.opcode == jal_op)
262 if (ip->r_format.opcode != spec_op)
264 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
268 static inline int is_sp_move_ins(union mips_instruction *ip)
270 #ifdef CONFIG_CPU_MICROMIPS
275 * jradiussp - NOT SUPPORTED
277 * microMIPS is not more fun...
279 if (mm_insn_16bit(ip->halfword[0])) {
280 union mips_instruction mmi;
282 mmi.word = (ip->halfword[0] << 16);
283 return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
284 mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
285 (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
286 mmi.mm16_r5_format.rt == 29);
288 return ip->mm_i_format.opcode == mm_addiu32_op &&
289 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
291 /* addiu/daddiu sp,sp,-imm */
292 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
294 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
300 static int get_frame_info(struct mips_frame_info *info)
302 #ifdef CONFIG_CPU_MICROMIPS
303 union mips_instruction *ip = (void *) (((char *) info->func) - 1);
305 union mips_instruction *ip = info->func;
307 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
310 info->pc_offset = -1;
311 info->frame_size = 0;
317 max_insns = 128U; /* unknown function size */
318 max_insns = min(128U, max_insns);
320 for (i = 0; i < max_insns; i++, ip++) {
324 if (!info->frame_size) {
325 if (is_sp_move_ins(ip))
327 #ifdef CONFIG_CPU_MICROMIPS
328 if (mm_insn_16bit(ip->halfword[0]))
332 if (ip->halfword[0] & mm_addiusp_func)
334 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
335 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
337 tmp = (ip->halfword[0] >> 1);
338 info->frame_size = -(signed short)(tmp & 0xf);
340 ip = (void *) &ip->halfword[1];
344 info->frame_size = - ip->i_format.simmediate;
348 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
350 ip->i_format.simmediate / sizeof(long);
354 if (info->frame_size && info->pc_offset >= 0) /* nested */
356 if (info->pc_offset < 0) /* leaf */
358 /* prologue seems boggus... */
363 static struct mips_frame_info schedule_mfi __read_mostly;
365 #ifdef CONFIG_KALLSYMS
366 static unsigned long get___schedule_addr(void)
368 return kallsyms_lookup_name("__schedule");
371 static unsigned long get___schedule_addr(void)
373 union mips_instruction *ip = (void *)schedule;
377 for (i = 0; i < max_insns; i++, ip++) {
378 if (ip->j_format.opcode == j_op)
379 return J_TARGET(ip, ip->j_format.target);
385 static int __init frame_info_init(void)
387 unsigned long size = 0;
388 #ifdef CONFIG_KALLSYMS
393 addr = get___schedule_addr();
395 addr = (unsigned long)schedule;
397 #ifdef CONFIG_KALLSYMS
398 kallsyms_lookup_size_offset(addr, &size, &ofs);
400 schedule_mfi.func = (void *)addr;
401 schedule_mfi.func_size = size;
403 get_frame_info(&schedule_mfi);
406 * Without schedule() frame info, result given by
407 * thread_saved_pc() and get_wchan() are not reliable.
409 if (schedule_mfi.pc_offset < 0)
410 printk("Can't analyze schedule() prologue at %p\n", schedule);
415 arch_initcall(frame_info_init);
418 * Return saved PC of a blocked thread.
420 unsigned long thread_saved_pc(struct task_struct *tsk)
422 struct thread_struct *t = &tsk->thread;
424 /* New born processes are a special case */
425 if (t->reg31 == (unsigned long) ret_from_fork)
427 if (schedule_mfi.pc_offset < 0)
429 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
433 #ifdef CONFIG_KALLSYMS
434 /* generic stack unwinding function */
435 unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
440 struct mips_frame_info info;
441 unsigned long size, ofs;
443 extern void ret_from_irq(void);
444 extern void ret_from_exception(void);
450 * If we reached the bottom of interrupt context,
451 * return saved pc in pt_regs.
453 if (pc == (unsigned long)ret_from_irq ||
454 pc == (unsigned long)ret_from_exception) {
455 struct pt_regs *regs;
456 if (*sp >= stack_page &&
457 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
458 regs = (struct pt_regs *)*sp;
460 if (__kernel_text_address(pc)) {
461 *sp = regs->regs[29];
462 *ra = regs->regs[31];
468 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
471 * Return ra if an exception occurred at the first instruction
473 if (unlikely(ofs == 0)) {
479 info.func = (void *)(pc - ofs);
480 info.func_size = ofs; /* analyze from start to ofs */
481 leaf = get_frame_info(&info);
485 if (*sp < stack_page ||
486 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
491 * For some extreme cases, get_frame_info() can
492 * consider wrongly a nested function as a leaf
493 * one. In that cases avoid to return always the
496 pc = pc != *ra ? *ra : 0;
498 pc = ((unsigned long *)(*sp))[info.pc_offset];
500 *sp += info.frame_size;
502 return __kernel_text_address(pc) ? pc : 0;
504 EXPORT_SYMBOL(unwind_stack_by_address);
506 /* used by show_backtrace() */
507 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
508 unsigned long pc, unsigned long *ra)
510 unsigned long stack_page = (unsigned long)task_stack_page(task);
511 return unwind_stack_by_address(stack_page, sp, pc, ra);
516 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
518 unsigned long get_wchan(struct task_struct *task)
520 unsigned long pc = 0;
521 #ifdef CONFIG_KALLSYMS
523 unsigned long ra = 0;
526 if (!task || task == current || task->state == TASK_RUNNING)
528 if (!task_stack_page(task))
531 pc = thread_saved_pc(task);
533 #ifdef CONFIG_KALLSYMS
534 sp = task->thread.reg29 + schedule_mfi.frame_size;
536 while (in_sched_functions(pc))
537 pc = unwind_stack(task, &sp, pc, &ra);
545 * Don't forget that the stack pointer must be aligned on a 8 bytes
546 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
548 unsigned long arch_align_stack(unsigned long sp)
550 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
551 sp -= get_random_int() & ~PAGE_MASK;
556 static void arch_dump_stack(void *info)
558 struct pt_regs *regs;
560 regs = get_irq_regs();
568 void arch_trigger_all_cpu_backtrace(bool include_self)
570 smp_call_function(arch_dump_stack, NULL, 1);
573 int mips_get_process_fp_mode(struct task_struct *task)
577 if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
578 value |= PR_FP_MODE_FR;
579 if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
580 value |= PR_FP_MODE_FRE;
585 int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
587 const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
588 unsigned long switch_count;
589 struct task_struct *t;
591 /* Check the value is valid */
592 if (value & ~known_bits)
595 /* Avoid inadvertently triggering emulation */
596 if ((value & PR_FP_MODE_FR) && cpu_has_fpu &&
597 !(current_cpu_data.fpu_id & MIPS_FPIR_F64))
599 if ((value & PR_FP_MODE_FRE) && cpu_has_fpu && !cpu_has_fre)
602 /* FR = 0 not supported in MIPS R6 */
603 if (!(value & PR_FP_MODE_FR) && cpu_has_fpu && cpu_has_mips_r6)
606 /* Save FP & vector context, then disable FPU & MSA */
607 if (task->signal == current->signal)
610 /* Prevent any threads from obtaining live FP context */
611 atomic_set(&task->mm->context.fp_mode_switching, 1);
612 smp_mb__after_atomic();
615 * If there are multiple online CPUs then wait until all threads whose
616 * FP mode is about to change have been context switched. This approach
617 * allows us to only worry about whether an FP mode switch is in
618 * progress when FP is first used in a tasks time slice. Pretty much all
619 * of the mode switch overhead can thus be confined to cases where mode
620 * switches are actually occuring. That is, to here. However for the
621 * thread performing the mode switch it may take a while...
623 if (num_online_cpus() > 1) {
624 spin_lock_irq(&task->sighand->siglock);
626 for_each_thread(task, t) {
630 switch_count = t->nvcsw + t->nivcsw;
633 spin_unlock_irq(&task->sighand->siglock);
635 spin_lock_irq(&task->sighand->siglock);
636 } while ((t->nvcsw + t->nivcsw) == switch_count);
639 spin_unlock_irq(&task->sighand->siglock);
643 * There are now no threads of the process with live FP context, so it
644 * is safe to proceed with the FP mode switch.
646 for_each_thread(task, t) {
647 /* Update desired FP register width */
648 if (value & PR_FP_MODE_FR) {
649 clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
651 set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
652 clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
655 /* Update desired FP single layout */
656 if (value & PR_FP_MODE_FRE)
657 set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
659 clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
662 /* Allow threads to use FP again */
663 atomic_set(&task->mm->context.fp_mode_switching, 0);