/* * 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 * Copyright (C) 2013  Imagination Technologies Ltd. */#include <linux/errno.h>#include <linux/sched.h>#include <linux/tick.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/export.h>#include <linux/ptrace.h>#include <linux/mman.h>#include <linux/personality.h>#include <linux/sys.h>#include <linux/init.h>#include <linux/completion.h>#include <linux/kallsyms.h>#include <linux/random.h> #include <asm/asm.h>#include <asm/bootinfo.h>#include <asm/cpu.h>#include <asm/dsp.h>#include <asm/fpu.h>#include <asm/msa.h>#include <asm/pgtable.h>#include <asm/mipsregs.h>#include <asm/processor.h>#include <asm/reg.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>#include <asm/irq_regs.h> #ifdef CONFIG_HOTPLUG_CPUvoid arch_cpu_idle_dead(void){	/* What the heck is this check doing ? */	if (!cpu_isset(smp_processor_id(), cpu_callin_map))		play_dead();}#endif asmlinkage void ret_from_fork(void);asmlinkage void ret_from_kernel_thread(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|ST0_FR|KU_MASK);	status |= KU_USER;	regs->cp0_status = status;	clear_used_math();	clear_fpu_owner();	init_dsp();	clear_thread_flag(TIF_USEDMSA);	clear_thread_flag(TIF_MSA_CTX_LIVE);	disable_msa();	regs->cp0_epc = pc;	regs->regs[29] = sp;} void exit_thread(void){} void flush_thread(void){} int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src){	/*	 * Save any process state which is live in hardware registers to the	 * parent context prior to duplication. This prevents the new child	 * state becoming stale if the parent is preempted before copy_thread()	 * gets a chance to save the parent's live hardware registers to the	 * child context.	 */	preempt_disable(); 	if (is_msa_enabled())		save_msa(current);	else if (is_fpu_owner())		_save_fp(current); 	save_dsp(current); 	preempt_enable(); 	*dst = *src;	return 0;} int copy_thread(unsigned long clone_flags, unsigned long usp,	unsigned long arg, struct task_struct *p){	struct thread_info *ti = task_thread_info(p);	struct pt_regs *childregs, *regs = current_pt_regs();	unsigned long childksp;	p->set_child_tid = p->clear_child_tid = NULL; 	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 	/* set up new TSS. */	childregs = (struct pt_regs *) childksp - 1;	/*  Put the stack after the struct pt_regs.  */	childksp = (unsigned long) childregs;	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);	if (unlikely(p->flags & PF_KTHREAD)) {		unsigned long status = p->thread.cp0_status;		memset(childregs, 0, sizeof(struct pt_regs));		ti->addr_limit = KERNEL_DS;		p->thread.reg16 = usp; /* fn */		p->thread.reg17 = arg;		p->thread.reg29 = childksp;		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)		status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |			 ((status & (ST0_KUC | ST0_IEC)) << 2);#else		status |= ST0_EXL;#endif		childregs->cp0_status = status;		return 0;	}	*childregs = *regs;	childregs->regs[7] = 0; /* Clear error flag */	childregs->regs[2] = 0; /* Child gets zero as return value */	if (usp)		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.	 */	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); 	clear_tsk_thread_flag(p, TIF_USEDFPU);	clear_tsk_thread_flag(p, TIF_USEDMSA);	clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE); #ifdef CONFIG_MIPS_MT_FPAFF	clear_tsk_thread_flag(p, TIF_FPUBOUND);#endif /* CONFIG_MIPS_MT_FPAFF */ 	if (clone_flags & CLONE_SETTLS)		ti->tp_value = regs->regs[7]; 	return 0;} #ifdef CONFIG_CC_STACKPROTECTOR#include <linux/stackprotector.h>unsigned long __stack_chk_guard __read_mostly;EXPORT_SYMBOL(__stack_chk_guard);#endif struct mips_frame_info {	void		*func;	unsigned long	func_size;	int		frame_size;	int		pc_offset;}; #define J_TARGET(pc,target)	\		(((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) static inline int is_ra_save_ins(union mips_instruction *ip){#ifdef CONFIG_CPU_MICROMIPS	union mips_instruction mmi; 	/*	 * swsp ra,offset	 * swm16 reglist,offset(sp)	 * swm32 reglist,offset(sp)	 * sw32 ra,offset(sp)	 * jradiussp - NOT SUPPORTED	 *	 * microMIPS is way more fun...	 */	if (mm_insn_16bit(ip->halfword[0])) {		mmi.word = (ip->halfword[0] << 16);		return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&			mmi.mm16_r5_format.rt == 31) ||		       (mmi.mm16_m_format.opcode == mm_pool16c_op &&			mmi.mm16_m_format.func == mm_swm16_op);	}	else {		mmi.halfword[0] = ip->halfword[1];		mmi.halfword[1] = ip->halfword[0];		return (mmi.mm_m_format.opcode == mm_pool32b_op &&			mmi.mm_m_format.rd > 9 &&			mmi.mm_m_format.base == 29 &&			mmi.mm_m_format.func == mm_swm32_func) ||		       (mmi.i_format.opcode == mm_sw32_op &&			mmi.i_format.rs == 29 &&			mmi.i_format.rt == 31);	}#else	/* 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;#endif} static inline int is_jump_ins(union mips_instruction *ip){#ifdef CONFIG_CPU_MICROMIPS	/*	 * jr16,jrc,jalr16,jalr16	 * jal	 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb	 * jraddiusp - NOT SUPPORTED	 *	 * microMIPS is kind of more fun...	 */	union mips_instruction mmi; 	mmi.word = (ip->halfword[0] << 16); 	if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&	    (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||	    ip->j_format.opcode == mm_jal32_op)		return 1;	if (ip->r_format.opcode != mm_pool32a_op ||			ip->r_format.func != mm_pool32axf_op)		return 0;	return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;#else	if (ip->j_format.opcode == j_op)		return 1;	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;#endif} static inline int is_sp_move_ins(union mips_instruction *ip){#ifdef CONFIG_CPU_MICROMIPS	/*	 * addiusp -imm	 * addius5 sp,-imm	 * addiu32 sp,sp,-imm	 * jradiussp - NOT SUPPORTED	 *	 * microMIPS is not more fun...	 */	if (mm_insn_16bit(ip->halfword[0])) {		union mips_instruction mmi; 		mmi.word = (ip->halfword[0] << 16);		return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&			mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||		       (mmi.mm16_r5_format.opcode == mm_pool16d_op &&			mmi.mm16_r5_format.rt == 29);	}	return ip->mm_i_format.opcode == mm_addiu32_op &&	       ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;#else	/* 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;#endif	return 0;} static int get_frame_info(struct mips_frame_info *info){#ifdef CONFIG_CPU_MICROMIPS	union mips_instruction *ip = (void *) (((char *) info->func) - 1);#else	union mips_instruction *ip = info->func;#endif	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_jump_ins(ip))			break;		if (!info->frame_size) {			if (is_sp_move_ins(ip))			{#ifdef CONFIG_CPU_MICROMIPS				if (mm_insn_16bit(ip->halfword[0]))				{					unsigned short tmp; 					if (ip->halfword[0] & mm_addiusp_func)					{						tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);						info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));					} else {						tmp = (ip->halfword[0] >> 1);						info->frame_size = -(signed short)(tmp & 0xf);					}					ip = (void *) &ip->halfword[1];					ip--;				} else#endif				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; #ifdef CONFIG_KALLSYMSstatic unsigned long get___schedule_addr(void){	return kallsyms_lookup_name("__schedule");}#elsestatic unsigned long get___schedule_addr(void){	union mips_instruction *ip = (void *)schedule;	int max_insns = 8;	int i; 	for (i = 0; i < max_insns; i++, ip++) {		if (ip->j_format.opcode == j_op)			return J_TARGET(ip, ip->j_format.target);	}	return 0;}#endif static int __init frame_info_init(void){	unsigned long size = 0;#ifdef CONFIG_KALLSYMS	unsigned long ofs;#endif	unsigned long addr; 	addr = get___schedule_addr();	if (!addr)		addr = (unsigned long)schedule; #ifdef CONFIG_KALLSYMS	kallsyms_lookup_size_offset(addr, &size, &ofs);#endif	schedule_mfi.func = (void *)addr;	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/* generic stack unwinding function */unsigned long notrace unwind_stack_by_address(unsigned long stack_page,					      unsigned long *sp,					      unsigned long pc,					      unsigned long *ra){	struct mips_frame_info info;	unsigned long size, ofs;	int leaf;	extern void ret_from_irq(void);	extern void ret_from_exception(void); 	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 occurred 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;}EXPORT_SYMBOL(unwind_stack_by_address); /* used by show_backtrace() */unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,

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