/* * This file is subject to the terms and conditions of the GNU General Public * License.  See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 1999, 2000 Silicon Graphics, Inc. * Copyright (C) 2004 Thiemo Seufer */#include <linux/errno.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/slab.h>#include <linux/mman.h>#include <linux/personality.h>#include <linux/sys.h>#include <linux/user.h>#include <linux/a.out.h>#include <linux/init.h>#include <linux/completion.h>#include <linux/kallsyms.h> #include <asm/bootinfo.h>#include <asm/cpu.h>#include <asm/dsp.h>#include <asm/fpu.h>#include <asm/pgtable.h>#include <asm/system.h>#include <asm/mipsregs.h>#include <asm/processor.h>#include <asm/uaccess.h>#include <asm/io.h>#include <asm/elf.h>#include <asm/isadep.h>#include <asm/inst.h>#include <asm/stacktrace.h> /* * The idle thread. There's no useful work to be done, so just try to conserve * power and have a low exit latency (ie sit in a loop waiting for somebody to * say that they'd like to reschedule) */ATTRIB_NORET void cpu_idle(void){	/* endless idle loop with no priority at all */	while (1) {		while (!need_resched()) {#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG			extern void smtc_idle_loop_hook(void); 			smtc_idle_loop_hook();#endif			if (cpu_wait)				(*cpu_wait)();		}		preempt_enable_no_resched();		schedule();		preempt_disable();	}} asmlinkage void ret_from_fork(void); void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp){	unsigned long status; 	/* New thread loses kernel privileges. */	status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);#ifdef CONFIG_64BIT	status &= ~ST0_FR;	status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;#endif	status |= KU_USER;	regs->cp0_status = status;	clear_used_math();	clear_fpu_owner();	if (cpu_has_dsp)		__init_dsp();	regs->cp0_epc = pc;	regs->regs[29] = sp;	current_thread_info()->addr_limit = USER_DS;} void exit_thread(void){} void flush_thread(void){} int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,	unsigned long unused, struct task_struct *p, struct pt_regs *regs){	struct thread_info *ti = task_thread_info(p);	struct pt_regs *childregs;	long childksp;	p->set_child_tid = p->clear_child_tid = NULL; 	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 	preempt_disable(); 	if (is_fpu_owner())		save_fp(p); 	if (cpu_has_dsp)		save_dsp(p); 	preempt_enable(); 	/* set up new TSS. */	childregs = (struct pt_regs *) childksp - 1;	*childregs = *regs;	childregs->regs[7] = 0;	/* Clear error flag */ #if defined(CONFIG_BINFMT_IRIX)	if (current->personality != PER_LINUX) {		/* Under IRIX things are a little different. */		childregs->regs[3] = 1;		regs->regs[3] = 0;	}#endif	childregs->regs[2] = 0;	/* Child gets zero as return value */	regs->regs[2] = p->pid; 	if (childregs->cp0_status & ST0_CU0) {		childregs->regs[28] = (unsigned long) ti;		childregs->regs[29] = childksp;		ti->addr_limit = KERNEL_DS;	} else {		childregs->regs[29] = usp;		ti->addr_limit = USER_DS;	}	p->thread.reg29 = (unsigned long) childregs;	p->thread.reg31 = (unsigned long) ret_from_fork; 	/*	 * New tasks lose permission to use the fpu. This accelerates context	 * switching for most programs since they don't use the fpu.	 */	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);	clear_tsk_thread_flag(p, TIF_USEDFPU); #ifdef CONFIG_MIPS_MT_FPAFF	/*	 * FPU affinity support is cleaner if we track the	 * user-visible CPU affinity from the very beginning.	 * The generic cpus_allowed mask will already have	 * been copied from the parent before copy_thread	 * is invoked.	 */	p->thread.user_cpus_allowed = p->cpus_allowed;#endif /* CONFIG_MIPS_MT_FPAFF */ 	if (clone_flags & CLONE_SETTLS)		ti->tp_value = regs->regs[7]; 	return 0;} /* Fill in the fpu structure for a core dump.. */int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r){	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu)); 	return 1;} void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs){	int i; 	for (i = 0; i < EF_R0; i++)		gp[i] = 0;	gp[EF_R0] = 0;	for (i = 1; i <= 31; i++)		gp[EF_R0 + i] = regs->regs[i];	gp[EF_R26] = 0;	gp[EF_R27] = 0;	gp[EF_LO] = regs->lo;	gp[EF_HI] = regs->hi;	gp[EF_CP0_EPC] = regs->cp0_epc;	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;	gp[EF_CP0_STATUS] = regs->cp0_status;	gp[EF_CP0_CAUSE] = regs->cp0_cause;#ifdef EF_UNUSED0	gp[EF_UNUSED0] = 0;#endif} int dump_task_regs (struct task_struct *tsk, elf_gregset_t *regs){	elf_dump_regs(*regs, task_pt_regs(tsk));	return 1;} int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr){	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); 	return 1;} /* * Create a kernel thread */static ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *)){	do_exit(fn(arg));} long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags){	struct pt_regs regs; 	memset(&regs, 0, sizeof(regs)); 	regs.regs[4] = (unsigned long) arg;	regs.regs[5] = (unsigned long) fn;	regs.cp0_epc = (unsigned long) kernel_thread_helper;	regs.cp0_status = read_c0_status();#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)	regs.cp0_status &= ~(ST0_KUP | ST0_IEC);	regs.cp0_status |= ST0_IEP;#else	regs.cp0_status |= ST0_EXL;#endif 	/* Ok, create the new process.. */	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);} /* * */struct mips_frame_info {	void		*func;	unsigned long	func_size;	int		frame_size;	int		pc_offset;}; static inline int is_ra_save_ins(union mips_instruction *ip){	/* sw / sd $ra, offset($sp) */	return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&		ip->i_format.rs == 29 &&		ip->i_format.rt == 31;} static inline int is_jal_jalr_jr_ins(union mips_instruction *ip){	if (ip->j_format.opcode == jal_op)		return 1;	if (ip->r_format.opcode != spec_op)		return 0;	return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;} static inline int is_sp_move_ins(union mips_instruction *ip){	/* addiu/daddiu sp,sp,-imm */	if (ip->i_format.rs != 29 || ip->i_format.rt != 29)		return 0;	if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)		return 1;	return 0;} static int get_frame_info(struct mips_frame_info *info){	union mips_instruction *ip = info->func;	unsigned max_insns = info->func_size / sizeof(union mips_instruction);	unsigned i; 	info->pc_offset = -1;	info->frame_size = 0; 	if (!ip)		goto err; 	if (max_insns == 0)		max_insns = 128U;	/* unknown function size */	max_insns = min(128U, max_insns); 	for (i = 0; i < max_insns; i++, ip++) { 		if (is_jal_jalr_jr_ins(ip))			break;		if (!info->frame_size) {			if (is_sp_move_ins(ip))				info->frame_size = - ip->i_format.simmediate;			continue;		}		if (info->pc_offset == -1 && is_ra_save_ins(ip)) {			info->pc_offset =				ip->i_format.simmediate / sizeof(long);			break;		}	}	if (info->frame_size && info->pc_offset >= 0) /* nested */		return 0;	if (info->pc_offset < 0) /* leaf */		return 1;	/* prologue seems boggus... */err:	return -1;} static struct mips_frame_info schedule_mfi __read_mostly; static int __init frame_info_init(void){	unsigned long size = 0;#ifdef CONFIG_KALLSYMS	unsigned long ofs; 	kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);#endif	schedule_mfi.func = schedule;	schedule_mfi.func_size = size; 	get_frame_info(&schedule_mfi); 	/*	 * Without schedule() frame info, result given by	 * thread_saved_pc() and get_wchan() are not reliable.	 */	if (schedule_mfi.pc_offset < 0)		printk("Can't analyze schedule() prologue at %p\n", schedule); 	return 0;} arch_initcall(frame_info_init); /* * Return saved PC of a blocked thread. */unsigned long thread_saved_pc(struct task_struct *tsk){	struct thread_struct *t = &tsk->thread; 	/* New born processes are a special case */	if (t->reg31 == (unsigned long) ret_from_fork)		return t->reg31;	if (schedule_mfi.pc_offset < 0)		return 0;	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];}  #ifdef CONFIG_KALLSYMS/* used by show_backtrace() */unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,			   unsigned long pc, unsigned long *ra){	unsigned long stack_page;	struct mips_frame_info info;	unsigned long size, ofs;	int leaf;	extern void ret_from_irq(void);	extern void ret_from_exception(void); 	stack_page = (unsigned long)task_stack_page(task);	if (!stack_page)		return 0; 	/*	 * If we reached the bottom of interrupt context,	 * return saved pc in pt_regs.	 */	if (pc == (unsigned long)ret_from_irq ||	    pc == (unsigned long)ret_from_exception) {		struct pt_regs *regs;		if (*sp >= stack_page &&		    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {			regs = (struct pt_regs *)*sp;			pc = regs->cp0_epc;			if (__kernel_text_address(pc)) {				*sp = regs->regs[29];				*ra = regs->regs[31];				return pc;			}		}		return 0;	}	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))		return 0;	/*	 * Return ra if an exception occured at the first instruction	 */	if (unlikely(ofs == 0)) {		pc = *ra;		*ra = 0;		return pc;	} 	info.func = (void *)(pc - ofs);	info.func_size = ofs;	/* analyze from start to ofs */	leaf = get_frame_info(&info);	if (leaf < 0)		return 0; 	if (*sp < stack_page ||	    *sp + info.frame_size > stack_page + THREAD_SIZE - 32)		return 0; 	if (leaf)		/*		 * For some extreme cases, get_frame_info() can		 * consider wrongly a nested function as a leaf		 * one. In that cases avoid to return always the		 * same value.		 */		pc = pc != *ra ? *ra : 0;	else		pc = ((unsigned long *)(*sp))[info.pc_offset]; 	*sp += info.frame_size;	*ra = 0;	return __kernel_text_address(pc) ? pc : 0;}#endif /* * get_wchan - a maintenance nightmare^W^Wpain in the ass ... */unsigned long get_wchan(struct task_struct *task){	unsigned long pc = 0;#ifdef CONFIG_KALLSYMS	unsigned long sp;	unsigned long ra = 0;#endif 	if (!task || task == current || task->state == TASK_RUNNING)		goto out;	if (!task_stack_page(task))		goto out; 	pc = thread_saved_pc(task); #ifdef CONFIG_KALLSYMS	sp = task->thread.reg29 + schedule_mfi.frame_size; 	while (in_sched_functions(pc))		pc = unwind_stack(task, &sp, pc, &ra);#endif out:	return pc;}