/* * arch/xtensa/kernel/process.c * * Xtensa Processor version. * * 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) 2001 - 2005 Tensilica Inc. * * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> * Chris Zankel <chris@zankel.net> * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca> * Kevin Chea */ #include <linux/errno.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/smp.h>#include <linux/stddef.h>#include <linux/unistd.h>#include <linux/ptrace.h>#include <linux/elf.h>#include <linux/init.h>#include <linux/prctl.h>#include <linux/init_task.h>#include <linux/module.h>#include <linux/mqueue.h>#include <linux/fs.h>#include <linux/slab.h> #include <asm/pgtable.h>#include <asm/uaccess.h>#include <asm/system.h>#include <asm/io.h>#include <asm/processor.h>#include <asm/platform.h>#include <asm/mmu.h>#include <asm/irq.h>#include <linux/atomic.h>#include <asm/asm-offsets.h>#include <asm/regs.h> extern void ret_from_fork(void); struct task_struct *current_set[NR_CPUS] = {&init_task, }; void (*pm_power_off)(void) = NULL;EXPORT_SYMBOL(pm_power_off);  #if XTENSA_HAVE_COPROCESSORS void coprocessor_release_all(struct thread_info *ti){	unsigned long cpenable;	int i; 	/* Make sure we don't switch tasks during this operation. */ 	preempt_disable(); 	/* Walk through all cp owners and release it for the requested one. */ 	cpenable = ti->cpenable; 	for (i = 0; i < XCHAL_CP_MAX; i++) {		if (coprocessor_owner[i] == ti) {			coprocessor_owner[i] = 0;			cpenable &= ~(1 << i);		}	} 	ti->cpenable = cpenable;	coprocessor_clear_cpenable(); 	preempt_enable();} void coprocessor_flush_all(struct thread_info *ti){	unsigned long cpenable;	int i; 	preempt_disable(); 	cpenable = ti->cpenable; 	for (i = 0; i < XCHAL_CP_MAX; i++) {		if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)			coprocessor_flush(ti, i);		cpenable >>= 1;	} 	preempt_enable();} #endif  /* * Powermanagement idle function, if any is provided by the platform. */ void cpu_idle(void){  	local_irq_enable(); 	/* endless idle loop with no priority at all */	while (1) {		while (!need_resched())			platform_idle();		preempt_enable_no_resched();		schedule();		preempt_disable();	}} /* * This is called when the thread calls exit(). */void exit_thread(void){#if XTENSA_HAVE_COPROCESSORS	coprocessor_release_all(current_thread_info());#endif} /* * Flush thread state. This is called when a thread does an execve() * Note that we flush coprocessor registers for the case execve fails. */void flush_thread(void){#if XTENSA_HAVE_COPROCESSORS	struct thread_info *ti = current_thread_info();	coprocessor_flush_all(ti);	coprocessor_release_all(ti);#endif} /* * This is called before the thread is copied.  */void prepare_to_copy(struct task_struct *tsk){#if XTENSA_HAVE_COPROCESSORS	coprocessor_flush_all(task_thread_info(tsk));#endif} /* * Copy thread. * * The stack layout for the new thread looks like this: * *	+------------------------+ <- sp in childregs (= tos) *	|       childregs        | *	+------------------------+ <- thread.sp = sp in dummy-frame *	|      dummy-frame       |    (saved in dummy-frame spill-area) *	+------------------------+ * * We create a dummy frame to return to ret_from_fork: *   a0 points to ret_from_fork (simulating a call4) *   sp points to itself (thread.sp) *   a2, a3 are unused. * * Note: This is a pristine frame, so we don't need any spill region on top of *       childregs. */ int copy_thread(unsigned long clone_flags, unsigned long usp,		unsigned long unused,                struct task_struct * p, struct pt_regs * regs){	struct pt_regs *childregs;	struct thread_info *ti;	unsigned long tos;	int user_mode = user_mode(regs); 	/* Set up new TSS. */	tos = (unsigned long)task_stack_page(p) + THREAD_SIZE;	if (user_mode)		childregs = (struct pt_regs*)(tos - PT_USER_SIZE);	else		childregs = (struct pt_regs*)tos - 1; 	*childregs = *regs; 	/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */	*((int*)childregs - 3) = (unsigned long)childregs;	*((int*)childregs - 4) = 0; 	childregs->areg[1] = tos;	childregs->areg[2] = 0;	p->set_child_tid = p->clear_child_tid = NULL;	p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1);	p->thread.sp = (unsigned long)childregs; 	if (user_mode(regs)) { 		int len = childregs->wmask & ~0xf;		childregs->areg[1] = usp;		memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],		       &regs->areg[XCHAL_NUM_AREGS - len/4], len);// FIXME: we need to set THREADPTR in thread_info...		if (clone_flags & CLONE_SETTLS)			childregs->areg[2] = childregs->areg[6]; 	} else {		/* In kernel space, we start a new thread with a new stack. */		childregs->wmask = 1;	} #if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)	ti = task_thread_info(p);	ti->cpenable = 0;#endif 	return 0;}  /* * These bracket the sleeping functions.. */ unsigned long get_wchan(struct task_struct *p){	unsigned long sp, pc;	unsigned long stack_page = (unsigned long) task_stack_page(p);	int count = 0; 	if (!p || p == current || p->state == TASK_RUNNING)		return 0; 	sp = p->thread.sp;	pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp); 	do {		if (sp < stack_page + sizeof(struct task_struct) ||		    sp >= (stack_page + THREAD_SIZE) ||		    pc == 0)			return 0;		if (!in_sched_functions(pc))			return pc; 		/* Stack layout: sp-4: ra, sp-3: sp' */ 		pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);		sp = *(unsigned long *)sp - 3;	} while (count++ < 16);	return 0;} /* * xtensa_gregset_t and 'struct pt_regs' are vastly different formats * of processor registers.  Besides different ordering, * xtensa_gregset_t contains non-live register information that * 'struct pt_regs' does not.  Exception handling (primarily) uses * 'struct pt_regs'.  Core files and ptrace use xtensa_gregset_t. * */ void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs){	unsigned long wb, ws, wm;	int live, last; 	wb = regs->windowbase;	ws = regs->windowstart;	wm = regs->wmask;	ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1); 	/* Don't leak any random bits. */ 	memset(elfregs, 0, sizeof (elfregs)); 	/* Note:  PS.EXCM is not set while user task is running; its	 * being set in regs->ps is for exception handling convenience.	 */ 	elfregs->pc		= regs->pc;	elfregs->ps		= (regs->ps & ~(1 << PS_EXCM_BIT));	elfregs->lbeg		= regs->lbeg;	elfregs->lend		= regs->lend;	elfregs->lcount		= regs->lcount;	elfregs->sar		= regs->sar;	elfregs->windowstart	= ws; 	live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;	last = XCHAL_NUM_AREGS - (wm >> 4) * 4;	memcpy(elfregs->a, regs->areg, live * 4);	memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);} int dump_fpu(void){	return 0;} asmlinkagelong xtensa_clone(unsigned long clone_flags, unsigned long newsp,                  void __user *parent_tid, void *child_tls,                  void __user *child_tid, long a5,                  struct pt_regs *regs){        if (!newsp)                newsp = regs->areg[1];        return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);} /* * xtensa_execve() executes a new program. */ asmlinkagelong xtensa_execve(const char __user *name,		   const char __user *const __user *argv,                   const char __user *const __user *envp,                   long a3, long a4, long a5,                   struct pt_regs *regs){	long error;	char * filename; 	filename = getname(name);	error = PTR_ERR(filename);	if (IS_ERR(filename))		goto out;	error = do_execve(filename, argv, envp, regs);	putname(filename);out:	return error;}