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 asmlinkage void ret_from_fork(void);
55 asmlinkage void ret_from_kernel_thread(void);
57 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
61 /* New thread loses kernel privileges. */
62 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
64 status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
67 regs->cp0_status = status;
76 void exit_thread(void)
80 void flush_thread(void)
84 int copy_thread(unsigned long clone_flags, unsigned long usp,
85 unsigned long arg, struct task_struct *p)
87 struct thread_info *ti = task_thread_info(p);
88 struct pt_regs *childregs, *regs = current_pt_regs();
89 unsigned long childksp;
90 p->set_child_tid = p->clear_child_tid = NULL;
92 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
104 /* set up new TSS. */
105 childregs = (struct pt_regs *) childksp - 1;
106 /* Put the stack after the struct pt_regs. */
107 childksp = (unsigned long) childregs;
108 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
109 if (unlikely(p->flags & PF_KTHREAD)) {
110 unsigned long status = p->thread.cp0_status;
111 memset(childregs, 0, sizeof(struct pt_regs));
112 ti->addr_limit = KERNEL_DS;
113 p->thread.reg16 = usp; /* fn */
114 p->thread.reg17 = arg;
115 p->thread.reg29 = childksp;
116 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
117 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
118 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
119 ((status & (ST0_KUC | ST0_IEC)) << 2);
123 childregs->cp0_status = status;
127 childregs->regs[7] = 0; /* Clear error flag */
128 childregs->regs[2] = 0; /* Child gets zero as return value */
130 childregs->regs[29] = usp;
131 ti->addr_limit = USER_DS;
133 p->thread.reg29 = (unsigned long) childregs;
134 p->thread.reg31 = (unsigned long) ret_from_fork;
137 * New tasks lose permission to use the fpu. This accelerates context
138 * switching for most programs since they don't use the fpu.
140 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
142 #ifdef CONFIG_MIPS_MT_SMTC
144 * SMTC restores TCStatus after Status, and the CU bits
147 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
149 clear_tsk_thread_flag(p, TIF_USEDFPU);
151 #ifdef CONFIG_MIPS_MT_FPAFF
152 clear_tsk_thread_flag(p, TIF_FPUBOUND);
153 #endif /* CONFIG_MIPS_MT_FPAFF */
155 if (clone_flags & CLONE_SETTLS)
156 ti->tp_value = regs->regs[7];
161 /* Fill in the fpu structure for a core dump.. */
162 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
164 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
169 void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
173 for (i = 0; i < EF_R0; i++)
176 for (i = 1; i <= 31; i++)
177 gp[EF_R0 + i] = regs->regs[i];
180 gp[EF_LO] = regs->lo;
181 gp[EF_HI] = regs->hi;
182 gp[EF_CP0_EPC] = regs->cp0_epc;
183 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
184 gp[EF_CP0_STATUS] = regs->cp0_status;
185 gp[EF_CP0_CAUSE] = regs->cp0_cause;
191 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
193 elf_dump_regs(*regs, task_pt_regs(tsk));
197 int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
199 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
204 #ifdef CONFIG_CC_STACKPROTECTOR
205 #include <linux/stackprotector.h>
206 unsigned long __stack_chk_guard __read_mostly;
207 EXPORT_SYMBOL(__stack_chk_guard);
213 struct mips_frame_info {
215 unsigned long func_size;
220 #define J_TARGET(pc,target) \
221 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
223 static inline int is_ra_save_ins(union mips_instruction *ip)
225 #ifdef CONFIG_CPU_MICROMIPS
226 union mips_instruction mmi;
230 * swm16 reglist,offset(sp)
231 * swm32 reglist,offset(sp)
233 * jradiussp - NOT SUPPORTED
235 * microMIPS is way more fun...
237 if (mm_insn_16bit(ip->halfword[0])) {
238 mmi.word = (ip->halfword[0] << 16);
239 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op &&
240 mmi.mm16_r5_format.rt == 31) ||
241 (mmi.mm16_m_format.opcode == mm_pool16c_op &&
242 mmi.mm16_m_format.func == mm_swm16_op));
245 mmi.halfword[0] = ip->halfword[1];
246 mmi.halfword[1] = ip->halfword[0];
247 return ((mmi.mm_m_format.opcode == mm_pool32b_op &&
248 mmi.mm_m_format.rd > 9 &&
249 mmi.mm_m_format.base == 29 &&
250 mmi.mm_m_format.func == mm_swm32_func) ||
251 (mmi.i_format.opcode == mm_sw32_op &&
252 mmi.i_format.rs == 29 &&
253 mmi.i_format.rt == 31));
256 /* sw / sd $ra, offset($sp) */
257 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
258 ip->i_format.rs == 29 &&
259 ip->i_format.rt == 31;
263 static inline int is_jump_ins(union mips_instruction *ip)
265 #ifdef CONFIG_CPU_MICROMIPS
267 * jr16,jrc,jalr16,jalr16
269 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
270 * jraddiusp - NOT SUPPORTED
272 * microMIPS is kind of more fun...
274 union mips_instruction mmi;
276 mmi.word = (ip->halfword[0] << 16);
278 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
279 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
280 ip->j_format.opcode == mm_jal32_op)
282 if (ip->r_format.opcode != mm_pool32a_op ||
283 ip->r_format.func != mm_pool32axf_op)
285 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op);
287 if (ip->j_format.opcode == j_op)
289 if (ip->j_format.opcode == jal_op)
291 if (ip->r_format.opcode != spec_op)
293 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
297 static inline int is_sp_move_ins(union mips_instruction *ip)
299 #ifdef CONFIG_CPU_MICROMIPS
304 * jradiussp - NOT SUPPORTED
306 * microMIPS is not more fun...
308 if (mm_insn_16bit(ip->halfword[0])) {
309 union mips_instruction mmi;
311 mmi.word = (ip->halfword[0] << 16);
312 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op &&
313 mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
314 (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
315 mmi.mm16_r5_format.rt == 29));
317 return (ip->mm_i_format.opcode == mm_addiu32_op &&
318 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29);
320 /* addiu/daddiu sp,sp,-imm */
321 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
323 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
329 static int get_frame_info(struct mips_frame_info *info)
331 #ifdef CONFIG_CPU_MICROMIPS
332 union mips_instruction *ip = (void *) (((char *) info->func) - 1);
334 union mips_instruction *ip = info->func;
336 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
339 info->pc_offset = -1;
340 info->frame_size = 0;
346 max_insns = 128U; /* unknown function size */
347 max_insns = min(128U, max_insns);
349 for (i = 0; i < max_insns; i++, ip++) {
353 if (!info->frame_size) {
354 if (is_sp_move_ins(ip))
356 #ifdef CONFIG_CPU_MICROMIPS
357 if (mm_insn_16bit(ip->halfword[0]))
361 if (ip->halfword[0] & mm_addiusp_func)
363 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
364 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
366 tmp = (ip->halfword[0] >> 1);
367 info->frame_size = -(signed short)(tmp & 0xf);
369 ip = (void *) &ip->halfword[1];
373 info->frame_size = - ip->i_format.simmediate;
377 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
379 ip->i_format.simmediate / sizeof(long);
383 if (info->frame_size && info->pc_offset >= 0) /* nested */
385 if (info->pc_offset < 0) /* leaf */
387 /* prologue seems boggus... */
392 static struct mips_frame_info schedule_mfi __read_mostly;
394 #ifdef CONFIG_KALLSYMS
395 static unsigned long get___schedule_addr(void)
397 return kallsyms_lookup_name("__schedule");
400 static unsigned long get___schedule_addr(void)
402 union mips_instruction *ip = (void *)schedule;
406 for (i = 0; i < max_insns; i++, ip++) {
407 if (ip->j_format.opcode == j_op)
408 return J_TARGET(ip, ip->j_format.target);
414 static int __init frame_info_init(void)
416 unsigned long size = 0;
417 #ifdef CONFIG_KALLSYMS
422 addr = get___schedule_addr();
424 addr = (unsigned long)schedule;
426 #ifdef CONFIG_KALLSYMS
427 kallsyms_lookup_size_offset(addr, &size, &ofs);
429 schedule_mfi.func = (void *)addr;
430 schedule_mfi.func_size = size;
432 get_frame_info(&schedule_mfi);
435 * Without schedule() frame info, result given by
436 * thread_saved_pc() and get_wchan() are not reliable.
438 if (schedule_mfi.pc_offset < 0)
439 printk("Can't analyze schedule() prologue at %p\n", schedule);
444 arch_initcall(frame_info_init);
447 * Return saved PC of a blocked thread.
449 unsigned long thread_saved_pc(struct task_struct *tsk)
451 struct thread_struct *t = &tsk->thread;
453 /* New born processes are a special case */
454 if (t->reg31 == (unsigned long) ret_from_fork)
456 if (schedule_mfi.pc_offset < 0)
458 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
462 #ifdef CONFIG_KALLSYMS
463 /* generic stack unwinding function */
464 unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
469 struct mips_frame_info info;
470 unsigned long size, ofs;
472 extern void ret_from_irq(void);
473 extern void ret_from_exception(void);
479 * If we reached the bottom of interrupt context,
480 * return saved pc in pt_regs.
482 if (pc == (unsigned long)ret_from_irq ||
483 pc == (unsigned long)ret_from_exception) {
484 struct pt_regs *regs;
485 if (*sp >= stack_page &&
486 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
487 regs = (struct pt_regs *)*sp;
489 if (__kernel_text_address(pc)) {
490 *sp = regs->regs[29];
491 *ra = regs->regs[31];
497 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
500 * Return ra if an exception occurred at the first instruction
502 if (unlikely(ofs == 0)) {
508 info.func = (void *)(pc - ofs);
509 info.func_size = ofs; /* analyze from start to ofs */
510 leaf = get_frame_info(&info);
514 if (*sp < stack_page ||
515 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
520 * For some extreme cases, get_frame_info() can
521 * consider wrongly a nested function as a leaf
522 * one. In that cases avoid to return always the
525 pc = pc != *ra ? *ra : 0;
527 pc = ((unsigned long *)(*sp))[info.pc_offset];
529 *sp += info.frame_size;
531 return __kernel_text_address(pc) ? pc : 0;
533 EXPORT_SYMBOL(unwind_stack_by_address);
535 /* used by show_backtrace() */
536 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
537 unsigned long pc, unsigned long *ra)
539 unsigned long stack_page = (unsigned long)task_stack_page(task);
540 return unwind_stack_by_address(stack_page, sp, pc, ra);
545 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
547 unsigned long get_wchan(struct task_struct *task)
549 unsigned long pc = 0;
550 #ifdef CONFIG_KALLSYMS
552 unsigned long ra = 0;
555 if (!task || task == current || task->state == TASK_RUNNING)
557 if (!task_stack_page(task))
560 pc = thread_saved_pc(task);
562 #ifdef CONFIG_KALLSYMS
563 sp = task->thread.reg29 + schedule_mfi.frame_size;
565 while (in_sched_functions(pc))
566 pc = unwind_stack(task, &sp, pc, &ra);
574 * Don't forget that the stack pointer must be aligned on a 8 bytes
575 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
577 unsigned long arch_align_stack(unsigned long sp)
579 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
580 sp -= get_random_int() & ~PAGE_MASK;