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);