forked from Minki/linux
261 lines
6.8 KiB
C
261 lines
6.8 KiB
C
/*
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* OpenRISC process.c
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* Modifications for the OpenRISC architecture:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* This file handles the architecture-dependent parts of process handling...
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*/
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#define __KERNEL_SYSCALLS__
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#include <stdarg.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/elfcore.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/init_task.h>
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#include <linux/mqueue.h>
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#include <linux/fs.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/spr_defs.h>
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#include <linux/smp.h>
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/*
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* Pointer to Current thread info structure.
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*
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* Used at user space -> kernel transitions.
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*/
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struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
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void machine_restart(void)
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{
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printk(KERN_INFO "*** MACHINE RESTART ***\n");
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__asm__("l.nop 1");
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}
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/*
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* Similar to machine_power_off, but don't shut off power. Add code
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* here to freeze the system for e.g. post-mortem debug purpose when
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* possible. This halt has nothing to do with the idle halt.
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*/
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void machine_halt(void)
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{
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printk(KERN_INFO "*** MACHINE HALT ***\n");
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__asm__("l.nop 1");
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}
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/* If or when software power-off is implemented, add code here. */
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void machine_power_off(void)
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{
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printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
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__asm__("l.nop 1");
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}
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void (*pm_power_off) (void) = machine_power_off;
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/*
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* When a process does an "exec", machine state like FPU and debug
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* registers need to be reset. This is a hook function for that.
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* Currently we don't have any such state to reset, so this is empty.
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*/
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void flush_thread(void)
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{
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}
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void show_regs(struct pt_regs *regs)
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{
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extern void show_registers(struct pt_regs *regs);
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/* __PHX__ cleanup this mess */
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show_registers(regs);
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}
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unsigned long thread_saved_pc(struct task_struct *t)
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{
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return (unsigned long)user_regs(t->stack)->pc;
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}
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void release_thread(struct task_struct *dead_task)
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{
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}
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/*
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* Copy the thread-specific (arch specific) info from the current
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* process to the new one p
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*/
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extern asmlinkage void ret_from_fork(void);
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/*
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* copy_thread
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* @clone_flags: flags
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* @usp: user stack pointer or fn for kernel thread
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* @arg: arg to fn for kernel thread; always NULL for userspace thread
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* @p: the newly created task
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* @regs: CPU context to copy for userspace thread; always NULL for kthread
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*
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* At the top of a newly initialized kernel stack are two stacked pt_reg
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* structures. The first (topmost) is the userspace context of the thread.
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* The second is the kernelspace context of the thread.
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*
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* A kernel thread will not be returning to userspace, so the topmost pt_regs
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* struct can be uninitialized; it _does_ need to exist, though, because
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* a kernel thread can become a userspace thread by doing a kernel_execve, in
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* which case the topmost context will be initialized and used for 'returning'
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* to userspace.
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*
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* The second pt_reg struct needs to be initialized to 'return' to
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* ret_from_fork. A kernel thread will need to set r20 to the address of
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* a function to call into (with arg in r22); userspace threads need to set
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* r20 to NULL in which case ret_from_fork will just continue a return to
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* userspace.
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*
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* A kernel thread 'fn' may return; this is effectively what happens when
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* kernel_execve is called. In that case, the userspace pt_regs must have
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* been initialized (which kernel_execve takes care of, see start_thread
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* below); ret_from_fork will then continue its execution causing the
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* 'kernel thread' to return to userspace as a userspace thread.
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*/
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int
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copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long arg, struct task_struct *p)
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{
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struct pt_regs *userregs;
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struct pt_regs *kregs;
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unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
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unsigned long top_of_kernel_stack;
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top_of_kernel_stack = sp;
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p->set_child_tid = p->clear_child_tid = NULL;
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/* Locate userspace context on stack... */
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sp -= STACK_FRAME_OVERHEAD; /* redzone */
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sp -= sizeof(struct pt_regs);
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userregs = (struct pt_regs *) sp;
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/* ...and kernel context */
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sp -= STACK_FRAME_OVERHEAD; /* redzone */
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sp -= sizeof(struct pt_regs);
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kregs = (struct pt_regs *)sp;
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if (unlikely(p->flags & PF_KTHREAD)) {
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memset(kregs, 0, sizeof(struct pt_regs));
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kregs->gpr[20] = usp; /* fn, kernel thread */
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kregs->gpr[22] = arg;
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} else {
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*userregs = *current_pt_regs();
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if (usp)
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userregs->sp = usp;
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userregs->gpr[11] = 0; /* Result from fork() */
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kregs->gpr[20] = 0; /* Userspace thread */
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}
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/*
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* _switch wants the kernel stack page in pt_regs->sp so that it
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* can restore it to thread_info->ksp... see _switch for details.
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*/
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kregs->sp = top_of_kernel_stack;
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kregs->gpr[9] = (unsigned long)ret_from_fork;
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task_thread_info(p)->ksp = (unsigned long)kregs;
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return 0;
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}
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/*
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* Set up a thread for executing a new program
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*/
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void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
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{
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unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
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set_fs(USER_DS);
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memset(regs, 0, sizeof(struct pt_regs));
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regs->pc = pc;
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regs->sr = sr;
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regs->sp = sp;
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}
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/* Fill in the fpu structure for a core dump. */
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
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{
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/* TODO */
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return 0;
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}
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extern struct thread_info *_switch(struct thread_info *old_ti,
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struct thread_info *new_ti);
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struct task_struct *__switch_to(struct task_struct *old,
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struct task_struct *new)
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{
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struct task_struct *last;
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struct thread_info *new_ti, *old_ti;
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unsigned long flags;
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local_irq_save(flags);
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/* current_set is an array of saved current pointers
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* (one for each cpu). we need them at user->kernel transition,
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* while we save them at kernel->user transition
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*/
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new_ti = new->stack;
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old_ti = old->stack;
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current_thread_info_set[smp_processor_id()] = new_ti;
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last = (_switch(old_ti, new_ti))->task;
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local_irq_restore(flags);
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return last;
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}
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/*
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* Write out registers in core dump format, as defined by the
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* struct user_regs_struct
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*/
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void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
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{
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dest[0] = 0; /* r0 */
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memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
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dest[32] = regs->pc;
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dest[33] = regs->sr;
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dest[34] = 0;
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dest[35] = 0;
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}
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unsigned long get_wchan(struct task_struct *p)
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{
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/* TODO */
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return 0;
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}
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