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
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/stddef.h>
17 #include <linux/unistd.h>
18 #include <linux/ptrace.h>
19 #include <linux/slab.h>
20 #include <linux/mman.h>
21 #include <linux/personality.h>
22 #include <linux/sys.h>
23 #include <linux/user.h>
24 #include <linux/a.out.h>
25 #include <linux/init.h>
26 #include <linux/completion.h>
27 #include <linux/kallsyms.h>
30 #include <asm/bootinfo.h>
34 #include <asm/pgtable.h>
35 #include <asm/system.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>
44 #ifdef CONFIG_MIPS_MT_SMTC
45 #include <asm/mipsmtregs.h>
46 extern void smtc_idle_loop_hook(void);
47 #endif /* CONFIG_MIPS_MT_SMTC */
50 * The idle thread. There's no useful work to be done, so just try to conserve
51 * power and have a low exit latency (ie sit in a loop waiting for somebody to
52 * say that they'd like to reschedule)
54 ATTRIB_NORET void cpu_idle(void)
56 /* endless idle loop with no priority at all */
58 while (!need_resched()) {
59 #ifdef CONFIG_MIPS_MT_SMTC
60 smtc_idle_loop_hook();
61 #endif /* CONFIG_MIPS_MT_SMTC */
65 preempt_enable_no_resched();
72 * Native o32 and N64 ABI without DSP ASE
74 struct mips_abi mips_abi = {
75 .do_signal = do_signal,
76 #ifdef CONFIG_TRAD_SIGNALS
77 .setup_frame = setup_frame,
79 .setup_rt_frame = setup_rt_frame
82 #ifdef CONFIG_MIPS32_O32
84 * o32 compatibility on 64-bit kernels, without DSP ASE
86 struct mips_abi mips_abi_32 = {
87 .do_signal = do_signal32,
88 .setup_frame = setup_frame_32,
89 .setup_rt_frame = setup_rt_frame_32
91 #endif /* CONFIG_MIPS32_O32 */
93 #ifdef CONFIG_MIPS32_N32
95 * N32 on 64-bit kernels, without DSP ASE
97 struct mips_abi mips_abi_n32 = {
98 .do_signal = do_signal,
99 .setup_rt_frame = setup_rt_frame_n32
101 #endif /* CONFIG_MIPS32_N32 */
103 asmlinkage void ret_from_fork(void);
105 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
107 unsigned long status;
109 /* New thread loses kernel privileges. */
110 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);
113 status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
116 regs->cp0_status = status;
123 current_thread_info()->addr_limit = USER_DS;
126 void exit_thread(void)
130 void flush_thread(void)
134 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
135 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
137 struct thread_info *ti = task_thread_info(p);
138 struct pt_regs *childregs;
140 p->set_child_tid = p->clear_child_tid = NULL;
142 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
154 /* set up new TSS. */
155 childregs = (struct pt_regs *) childksp - 1;
157 childregs->regs[7] = 0; /* Clear error flag */
159 #if defined(CONFIG_BINFMT_IRIX)
160 if (current->personality != PER_LINUX) {
161 /* Under IRIX things are a little different. */
162 childregs->regs[3] = 1;
166 childregs->regs[2] = 0; /* Child gets zero as return value */
167 regs->regs[2] = p->pid;
169 if (childregs->cp0_status & ST0_CU0) {
170 childregs->regs[28] = (unsigned long) ti;
171 childregs->regs[29] = childksp;
172 ti->addr_limit = KERNEL_DS;
174 childregs->regs[29] = usp;
175 ti->addr_limit = USER_DS;
177 p->thread.reg29 = (unsigned long) childregs;
178 p->thread.reg31 = (unsigned long) ret_from_fork;
181 * New tasks lose permission to use the fpu. This accelerates context
182 * switching for most programs since they don't use the fpu.
184 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
185 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
186 clear_tsk_thread_flag(p, TIF_USEDFPU);
188 #ifdef CONFIG_MIPS_MT_FPAFF
190 * FPU affinity support is cleaner if we track the
191 * user-visible CPU affinity from the very beginning.
192 * The generic cpus_allowed mask will already have
193 * been copied from the parent before copy_thread
196 p->thread.user_cpus_allowed = p->cpus_allowed;
197 #endif /* CONFIG_MIPS_MT_FPAFF */
199 if (clone_flags & CLONE_SETTLS)
200 ti->tp_value = regs->regs[7];
205 /* Fill in the fpu structure for a core dump.. */
206 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
208 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
213 void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
217 for (i = 0; i < EF_R0; i++)
220 for (i = 1; i <= 31; i++)
221 gp[EF_R0 + i] = regs->regs[i];
224 gp[EF_LO] = regs->lo;
225 gp[EF_HI] = regs->hi;
226 gp[EF_CP0_EPC] = regs->cp0_epc;
227 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
228 gp[EF_CP0_STATUS] = regs->cp0_status;
229 gp[EF_CP0_CAUSE] = regs->cp0_cause;
235 int dump_task_regs (struct task_struct *tsk, elf_gregset_t *regs)
237 elf_dump_regs(*regs, task_pt_regs(tsk));
241 int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr)
243 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
249 * Create a kernel thread
251 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
256 long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
260 memset(®s, 0, sizeof(regs));
262 regs.regs[4] = (unsigned long) arg;
263 regs.regs[5] = (unsigned long) fn;
264 regs.cp0_epc = (unsigned long) kernel_thread_helper;
265 regs.cp0_status = read_c0_status();
266 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
267 regs.cp0_status &= ~(ST0_KUP | ST0_IEC);
268 regs.cp0_status |= ST0_IEP;
270 regs.cp0_status |= ST0_EXL;
273 /* Ok, create the new process.. */
274 return do_fork(flags | CLONE_VM | CLONE_UNTRACED | CLONE_KTHREAD,
275 0, ®s, 0, NULL, NULL);
281 struct mips_frame_info {
283 unsigned long func_size;
288 static inline int is_ra_save_ins(union mips_instruction *ip)
290 /* sw / sd $ra, offset($sp) */
291 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
292 ip->i_format.rs == 29 &&
293 ip->i_format.rt == 31;
296 static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
298 if (ip->j_format.opcode == jal_op)
300 if (ip->r_format.opcode != spec_op)
302 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
305 static inline int is_sp_move_ins(union mips_instruction *ip)
307 /* addiu/daddiu sp,sp,-imm */
308 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
310 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
315 static int get_frame_info(struct mips_frame_info *info)
317 union mips_instruction *ip = info->func;
318 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
321 info->pc_offset = -1;
322 info->frame_size = 0;
328 max_insns = 128U; /* unknown function size */
329 max_insns = min(128U, max_insns);
331 for (i = 0; i < max_insns; i++, ip++) {
333 if (is_jal_jalr_jr_ins(ip))
335 if (!info->frame_size) {
336 if (is_sp_move_ins(ip))
337 info->frame_size = - ip->i_format.simmediate;
340 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
342 ip->i_format.simmediate / sizeof(long);
346 if (info->frame_size && info->pc_offset >= 0) /* nested */
348 if (info->pc_offset < 0) /* leaf */
350 /* prologue seems boggus... */
355 static struct mips_frame_info schedule_mfi __read_mostly;
357 static int __init frame_info_init(void)
359 unsigned long size = 0;
360 #ifdef CONFIG_KALLSYMS
363 kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
365 schedule_mfi.func = schedule;
366 schedule_mfi.func_size = size;
368 get_frame_info(&schedule_mfi);
371 * Without schedule() frame info, result given by
372 * thread_saved_pc() and get_wchan() are not reliable.
374 if (schedule_mfi.pc_offset < 0)
375 printk("Can't analyze schedule() prologue at %p\n", schedule);
380 arch_initcall(frame_info_init);
383 * Return saved PC of a blocked thread.
385 unsigned long thread_saved_pc(struct task_struct *tsk)
387 struct thread_struct *t = &tsk->thread;
389 /* New born processes are a special case */
390 if (t->reg31 == (unsigned long) ret_from_fork)
392 if (schedule_mfi.pc_offset < 0)
394 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
398 #ifdef CONFIG_KALLSYMS
399 /* used by show_backtrace() */
400 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
401 unsigned long pc, unsigned long *ra)
403 unsigned long stack_page;
404 struct mips_frame_info info;
405 unsigned long size, ofs;
407 extern void ret_from_irq(void);
408 extern void ret_from_exception(void);
410 stack_page = (unsigned long)task_stack_page(task);
415 * If we reached the bottom of interrupt context,
416 * return saved pc in pt_regs.
418 if (pc == (unsigned long)ret_from_irq ||
419 pc == (unsigned long)ret_from_exception) {
420 struct pt_regs *regs;
421 if (*sp >= stack_page &&
422 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
423 regs = (struct pt_regs *)*sp;
425 if (__kernel_text_address(pc)) {
426 *sp = regs->regs[29];
427 *ra = regs->regs[31];
433 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
436 * Return ra if an exception occured at the first instruction
438 if (unlikely(ofs == 0)) {
444 info.func = (void *)(pc - ofs);
445 info.func_size = ofs; /* analyze from start to ofs */
446 leaf = get_frame_info(&info);
450 if (*sp < stack_page ||
451 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
456 * For some extreme cases, get_frame_info() can
457 * consider wrongly a nested function as a leaf
458 * one. In that cases avoid to return always the
461 pc = pc != *ra ? *ra : 0;
463 pc = ((unsigned long *)(*sp))[info.pc_offset];
465 *sp += info.frame_size;
467 return __kernel_text_address(pc) ? pc : 0;
472 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
474 unsigned long get_wchan(struct task_struct *task)
476 unsigned long pc = 0;
477 #ifdef CONFIG_KALLSYMS
479 unsigned long ra = 0;
482 if (!task || task == current || task->state == TASK_RUNNING)
484 if (!task_stack_page(task))
487 pc = thread_saved_pc(task);
489 #ifdef CONFIG_KALLSYMS
490 sp = task->thread.reg29 + schedule_mfi.frame_size;
492 while (in_sched_functions(pc))
493 pc = unwind_stack(task, &sp, pc, &ra);