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/user.h>
25 #include <linux/init.h>
26 #include <linux/completion.h>
27 #include <linux/kallsyms.h>
28 #include <linux/random.h>
31 #include <asm/bootinfo.h>
35 #include <asm/pgtable.h>
36 #include <asm/mipsregs.h>
37 #include <asm/processor.h>
38 #include <asm/uaccess.h>
41 #include <asm/isadep.h>
43 #include <asm/stacktrace.h>
45 #ifdef CONFIG_HOTPLUG_CPU
46 void arch_cpu_idle_dead(void)
48 /* What the heck is this check doing ? */
49 if (!cpu_isset(smp_processor_id(), cpu_callin_map))
54 void arch_cpu_idle(void)
56 #ifdef CONFIG_MIPS_MT_SMTC
57 extern void smtc_idle_loop_hook(void);
59 smtc_idle_loop_hook();
67 asmlinkage void ret_from_fork(void);
68 asmlinkage void ret_from_kernel_thread(void);
70 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
74 /* New thread loses kernel privileges. */
75 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
77 status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
80 regs->cp0_status = status;
89 void exit_thread(void)
93 void flush_thread(void)
97 int copy_thread(unsigned long clone_flags, unsigned long usp,
98 unsigned long arg, struct task_struct *p)
100 struct thread_info *ti = task_thread_info(p);
101 struct pt_regs *childregs, *regs = current_pt_regs();
102 unsigned long childksp;
103 p->set_child_tid = p->clear_child_tid = NULL;
105 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
117 /* set up new TSS. */
118 childregs = (struct pt_regs *) childksp - 1;
119 /* Put the stack after the struct pt_regs. */
120 childksp = (unsigned long) childregs;
121 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
122 if (unlikely(p->flags & PF_KTHREAD)) {
123 unsigned long status = p->thread.cp0_status;
124 memset(childregs, 0, sizeof(struct pt_regs));
125 ti->addr_limit = KERNEL_DS;
126 p->thread.reg16 = usp; /* fn */
127 p->thread.reg17 = arg;
128 p->thread.reg29 = childksp;
129 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
130 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
131 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
132 ((status & (ST0_KUC | ST0_IEC)) << 2);
136 childregs->cp0_status = status;
140 childregs->regs[7] = 0; /* Clear error flag */
141 childregs->regs[2] = 0; /* Child gets zero as return value */
143 childregs->regs[29] = usp;
144 ti->addr_limit = USER_DS;
146 p->thread.reg29 = (unsigned long) childregs;
147 p->thread.reg31 = (unsigned long) ret_from_fork;
150 * New tasks lose permission to use the fpu. This accelerates context
151 * switching for most programs since they don't use the fpu.
153 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
155 #ifdef CONFIG_MIPS_MT_SMTC
157 * SMTC restores TCStatus after Status, and the CU bits
160 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
162 clear_tsk_thread_flag(p, TIF_USEDFPU);
164 #ifdef CONFIG_MIPS_MT_FPAFF
165 clear_tsk_thread_flag(p, TIF_FPUBOUND);
166 #endif /* CONFIG_MIPS_MT_FPAFF */
168 if (clone_flags & CLONE_SETTLS)
169 ti->tp_value = regs->regs[7];
174 /* Fill in the fpu structure for a core dump.. */
175 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
177 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
182 void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
186 for (i = 0; i < EF_R0; i++)
189 for (i = 1; i <= 31; i++)
190 gp[EF_R0 + i] = regs->regs[i];
193 gp[EF_LO] = regs->lo;
194 gp[EF_HI] = regs->hi;
195 gp[EF_CP0_EPC] = regs->cp0_epc;
196 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
197 gp[EF_CP0_STATUS] = regs->cp0_status;
198 gp[EF_CP0_CAUSE] = regs->cp0_cause;
204 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
206 elf_dump_regs(*regs, task_pt_regs(tsk));
210 int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
212 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
220 struct mips_frame_info {
222 unsigned long func_size;
227 #define J_TARGET(pc,target) \
228 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
230 static inline int is_ra_save_ins(union mips_instruction *ip)
232 #ifdef CONFIG_CPU_MICROMIPS
233 union mips_instruction mmi;
237 * swm16 reglist,offset(sp)
238 * swm32 reglist,offset(sp)
240 * jradiussp - NOT SUPPORTED
242 * microMIPS is way more fun...
244 if (mm_insn_16bit(ip->halfword[0])) {
245 mmi.word = (ip->halfword[0] << 16);
246 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op &&
247 mmi.mm16_r5_format.rt == 31) ||
248 (mmi.mm16_m_format.opcode == mm_pool16c_op &&
249 mmi.mm16_m_format.func == mm_swm16_op));
252 mmi.halfword[0] = ip->halfword[1];
253 mmi.halfword[1] = ip->halfword[0];
254 return ((mmi.mm_m_format.opcode == mm_pool32b_op &&
255 mmi.mm_m_format.rd > 9 &&
256 mmi.mm_m_format.base == 29 &&
257 mmi.mm_m_format.func == mm_swm32_func) ||
258 (mmi.i_format.opcode == mm_sw32_op &&
259 mmi.i_format.rs == 29 &&
260 mmi.i_format.rt == 31));
263 /* sw / sd $ra, offset($sp) */
264 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
265 ip->i_format.rs == 29 &&
266 ip->i_format.rt == 31;
270 static inline int is_jump_ins(union mips_instruction *ip)
272 #ifdef CONFIG_CPU_MICROMIPS
274 * jr16,jrc,jalr16,jalr16
276 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
277 * jraddiusp - NOT SUPPORTED
279 * microMIPS is kind of more fun...
281 union mips_instruction mmi;
283 mmi.word = (ip->halfword[0] << 16);
285 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
286 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
287 ip->j_format.opcode == mm_jal32_op)
289 if (ip->r_format.opcode != mm_pool32a_op ||
290 ip->r_format.func != mm_pool32axf_op)
292 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op);
294 if (ip->j_format.opcode == j_op)
296 if (ip->j_format.opcode == jal_op)
298 if (ip->r_format.opcode != spec_op)
300 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
304 static inline int is_sp_move_ins(union mips_instruction *ip)
306 #ifdef CONFIG_CPU_MICROMIPS
311 * jradiussp - NOT SUPPORTED
313 * microMIPS is not more fun...
315 if (mm_insn_16bit(ip->halfword[0])) {
316 union mips_instruction mmi;
318 mmi.word = (ip->halfword[0] << 16);
319 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op &&
320 mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
321 (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
322 mmi.mm16_r5_format.rt == 29));
324 return (ip->mm_i_format.opcode == mm_addiu32_op &&
325 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29);
327 /* addiu/daddiu sp,sp,-imm */
328 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
330 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
336 static int get_frame_info(struct mips_frame_info *info)
338 #ifdef CONFIG_CPU_MICROMIPS
339 union mips_instruction *ip = (void *) (((char *) info->func) - 1);
341 union mips_instruction *ip = info->func;
343 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
346 info->pc_offset = -1;
347 info->frame_size = 0;
353 max_insns = 128U; /* unknown function size */
354 max_insns = min(128U, max_insns);
356 for (i = 0; i < max_insns; i++, ip++) {
360 if (!info->frame_size) {
361 if (is_sp_move_ins(ip))
363 #ifdef CONFIG_CPU_MICROMIPS
364 if (mm_insn_16bit(ip->halfword[0]))
368 if (ip->halfword[0] & mm_addiusp_func)
370 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
371 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
373 tmp = (ip->halfword[0] >> 1);
374 info->frame_size = -(signed short)(tmp & 0xf);
376 ip = (void *) &ip->halfword[1];
380 info->frame_size = - ip->i_format.simmediate;
384 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
386 ip->i_format.simmediate / sizeof(long);
390 if (info->frame_size && info->pc_offset >= 0) /* nested */
392 if (info->pc_offset < 0) /* leaf */
394 /* prologue seems boggus... */
399 static struct mips_frame_info schedule_mfi __read_mostly;
401 #ifdef CONFIG_KALLSYMS
402 static unsigned long get___schedule_addr(void)
404 return kallsyms_lookup_name("__schedule");
407 static unsigned long get___schedule_addr(void)
409 union mips_instruction *ip = (void *)schedule;
413 for (i = 0; i < max_insns; i++, ip++) {
414 if (ip->j_format.opcode == j_op)
415 return J_TARGET(ip, ip->j_format.target);
421 static int __init frame_info_init(void)
423 unsigned long size = 0;
424 #ifdef CONFIG_KALLSYMS
429 addr = get___schedule_addr();
431 addr = (unsigned long)schedule;
433 #ifdef CONFIG_KALLSYMS
434 kallsyms_lookup_size_offset(addr, &size, &ofs);
436 schedule_mfi.func = (void *)addr;
437 schedule_mfi.func_size = size;
439 get_frame_info(&schedule_mfi);
442 * Without schedule() frame info, result given by
443 * thread_saved_pc() and get_wchan() are not reliable.
445 if (schedule_mfi.pc_offset < 0)
446 printk("Can't analyze schedule() prologue at %p\n", schedule);
451 arch_initcall(frame_info_init);
454 * Return saved PC of a blocked thread.
456 unsigned long thread_saved_pc(struct task_struct *tsk)
458 struct thread_struct *t = &tsk->thread;
460 /* New born processes are a special case */
461 if (t->reg31 == (unsigned long) ret_from_fork)
463 if (schedule_mfi.pc_offset < 0)
465 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
469 #ifdef CONFIG_KALLSYMS
470 /* generic stack unwinding function */
471 unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
476 struct mips_frame_info info;
477 unsigned long size, ofs;
479 extern void ret_from_irq(void);
480 extern void ret_from_exception(void);
486 * If we reached the bottom of interrupt context,
487 * return saved pc in pt_regs.
489 if (pc == (unsigned long)ret_from_irq ||
490 pc == (unsigned long)ret_from_exception) {
491 struct pt_regs *regs;
492 if (*sp >= stack_page &&
493 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
494 regs = (struct pt_regs *)*sp;
496 if (__kernel_text_address(pc)) {
497 *sp = regs->regs[29];
498 *ra = regs->regs[31];
504 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
507 * Return ra if an exception occurred at the first instruction
509 if (unlikely(ofs == 0)) {
515 info.func = (void *)(pc - ofs);
516 info.func_size = ofs; /* analyze from start to ofs */
517 leaf = get_frame_info(&info);
521 if (*sp < stack_page ||
522 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
527 * For some extreme cases, get_frame_info() can
528 * consider wrongly a nested function as a leaf
529 * one. In that cases avoid to return always the
532 pc = pc != *ra ? *ra : 0;
534 pc = ((unsigned long *)(*sp))[info.pc_offset];
536 *sp += info.frame_size;
538 return __kernel_text_address(pc) ? pc : 0;
540 EXPORT_SYMBOL(unwind_stack_by_address);
542 /* used by show_backtrace() */
543 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
544 unsigned long pc, unsigned long *ra)
546 unsigned long stack_page = (unsigned long)task_stack_page(task);
547 return unwind_stack_by_address(stack_page, sp, pc, ra);
552 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
554 unsigned long get_wchan(struct task_struct *task)
556 unsigned long pc = 0;
557 #ifdef CONFIG_KALLSYMS
559 unsigned long ra = 0;
562 if (!task || task == current || task->state == TASK_RUNNING)
564 if (!task_stack_page(task))
567 pc = thread_saved_pc(task);
569 #ifdef CONFIG_KALLSYMS
570 sp = task->thread.reg29 + schedule_mfi.frame_size;
572 while (in_sched_functions(pc))
573 pc = unwind_stack(task, &sp, pc, &ra);
581 * Don't forget that the stack pointer must be aligned on a 8 bytes
582 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
584 unsigned long arch_align_stack(unsigned long sp)
586 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
587 sp -= get_random_int() & ~PAGE_MASK;