/* * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Amit Bhor, Kanika Nema: Codito Technologies 2004 */ #include <linux/errno.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/mm.h>#include <linux/fs.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/slab.h>#include <linux/syscalls.h>#include <linux/elf.h>#include <linux/tick.h> SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr){	task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;	return 0;} /* * We return the user space TLS data ptr as sys-call return code * Ideally it should be copy to user. * However we can cheat by the fact that some sys-calls do return * absurdly high values * Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx * it won't be considered a sys-call error * and it will be loads better than copy-to-user, which is a definite * D-TLB Miss */SYSCALL_DEFINE0(arc_gettls){	return task_thread_info(current)->thr_ptr;} void arch_cpu_idle(void){	/* sleep, but enable all interrupts before committing */	__asm__("sleep 0x3");} asmlinkage void ret_from_fork(void); /* * Copy architecture-specific thread state * * Layout of Child kernel mode stack as setup at the end of this function is * * |     ...        | * |     ...        | * |    unused      | * |                | * ------------------ * |     r25        |   <==== top of Stack (thread.ksp) * ~                ~ * |    --to--      |   (CALLEE Regs of user mode) * |     r13        | * ------------------ * |     fp         | * |    blink       |   @ret_from_fork * ------------------ * |                | * ~                ~ * ~                ~ * |                | * ------------------ * |     r12        | * ~                ~ * |    --to--      |   (scratch Regs of user mode) * |     r0         | * ------------------ * |      SP        | * |    orig_r0     | * |    event/ECR   | * |    user_r25    | * ------------------  <===== END of PAGE */int copy_thread(unsigned long clone_flags,		unsigned long usp, unsigned long kthread_arg,		struct task_struct *p){	struct pt_regs *c_regs;        /* child's pt_regs */	unsigned long *childksp;       /* to unwind out of __switch_to() */	struct callee_regs *c_callee;  /* child's callee regs */	struct callee_regs *parent_callee;  /* paren't callee */	struct pt_regs *regs = current_pt_regs(); 	/* Mark the specific anchors to begin with (see pic above) */	c_regs = task_pt_regs(p);	childksp = (unsigned long *)c_regs - 2;  /* 2 words for FP/BLINK */	c_callee = ((struct callee_regs *)childksp) - 1; 	/*	 * __switch_to() uses thread.ksp to start unwinding stack	 * For kernel threads we don't need to create callee regs, the	 * stack layout nevertheless needs to remain the same.	 * Also, since __switch_to anyways unwinds callee regs, we use	 * this to populate kernel thread entry-pt/args into callee regs,	 * so that ret_from_kernel_thread() becomes simpler.	 */	p->thread.ksp = (unsigned long)c_callee;	/* THREAD_KSP */ 	/* __switch_to expects FP(0), BLINK(return addr) at top */	childksp[0] = 0;			/* fp */	childksp[1] = (unsigned long)ret_from_fork; /* blink */ 	if (unlikely(p->flags & PF_KTHREAD)) {		memset(c_regs, 0, sizeof(struct pt_regs)); 		c_callee->r13 = kthread_arg;		c_callee->r14 = usp;  /* function */ 		return 0;	} 	/*--------- User Task Only --------------*/ 	/* __switch_to expects FP(0), BLINK(return addr) at top of stack */	childksp[0] = 0;				/* for POP fp */	childksp[1] = (unsigned long)ret_from_fork;	/* for POP blink */ 	/* Copy parents pt regs on child's kernel mode stack */	*c_regs = *regs; 	if (usp)		c_regs->sp = usp; 	c_regs->r0 = 0;		/* fork returns 0 in child */ 	parent_callee = ((struct callee_regs *)regs) - 1;	*c_callee = *parent_callee; 	if (unlikely(clone_flags & CLONE_SETTLS)) {		/*		 * set task's userland tls data ptr from 4th arg		 * clone C-lib call is difft from clone sys-call		 */		task_thread_info(p)->thr_ptr = regs->r3;	} else {		/* Normal fork case: set parent's TLS ptr in child */		task_thread_info(p)->thr_ptr =		task_thread_info(current)->thr_ptr;	} 	return 0;} /* * Do necessary setup to start up a new user task */void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp){	regs->sp = usp;	regs->ret = pc; 	/*	 * [U]ser Mode bit set	 * [L] ZOL loop inhibited to begin with - cleared by a LP insn	 * Interrupts enabled	 */	regs->status32 = STATUS_U_MASK | STATUS_L_MASK |			 STATUS_E1_MASK | STATUS_E2_MASK; 	/* bogus seed values for debugging */	regs->lp_start = 0x10;	regs->lp_end = 0x80;} /* * Some archs flush debug and FPU info here */void flush_thread(void){} /* * Free any architecture-specific thread data structures, etc. */void exit_thread(void){} int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu){	return 0;} int elf_check_arch(const struct elf32_hdr *x){	unsigned int eflags; 	if (x->e_machine != EM_ARCOMPACT)		return 0; 	eflags = x->e_flags;	if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) {		pr_err("ABI mismatch - you need newer toolchain\n");		force_sigsegv(SIGSEGV, current);		return 0;	} 	return 1;}EXPORT_SYMBOL(elf_check_arch);