/*
* OpenRISC process.c
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* This file handles the architecture-dependent parts of process handling...
*/
#define __KERNEL_SYSCALLS__
#include <stdarg.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/elfcore.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init_task.h>
#include <linux/mqueue.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/spr_defs.h>
#include <linux/smp.h>
/*
* Pointer to Current thread info structure.
*
* Used at user space -> kernel transitions.
*/
struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
void machine_restart(void)
{
printk(KERN_INFO "*** MACHINE RESTART ***\n");
__asm__("l.nop 1");
}
/*
* Similar to machine_power_off, but don't shut off power. Add code
* here to freeze the system for e.g. post-mortem debug purpose when
* possible. This halt has nothing to do with the idle halt.
*/
void machine_halt(void)
{
printk(KERN_INFO "*** MACHINE HALT ***\n");
__asm__("l.nop 1");
}
/* If or when software power-off is implemented, add code here. */
void machine_power_off(void)
{
printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
__asm__("l.nop 1");
}
void (*pm_power_off) (void) = machine_power_off;
/*
* When a process does an "exec", machine state like FPU and debug
* registers need to be reset. This is a hook function for that.
* Currently we don't have any such state to reset, so this is empty.
*/
void flush_thread(void)
{
}
void show_regs(struct pt_regs *regs)
{
extern void show_registers(struct pt_regs *regs);
/* __PHX__ cleanup this mess */
show_registers(regs);
}
unsigned long thread_saved_pc(struct task_struct *t)
{
return (unsigned long)user_regs(t->stack)->pc;
}
void release_thread(struct task_struct *dead_task)
{
}
/*
* Copy the thread-specific (arch specific) info from the current
* process to the new one p
*/
extern asmlinkage void ret_from_fork(void);
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 pt_regs *kregs;
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
struct thread_info *ti;
unsigned long top_of_kernel_stack;
top_of_kernel_stack = sp;
p->set_child_tid = p->clear_child_tid = NULL;
/* Copy registers */
/* redzone */
sp -= STACK_FRAME_OVERHEAD;
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *)sp;
/* Copy parent registers */
*childregs = *regs;
if ((childregs->sr & SPR_SR_SM) == 1) {
/* for kernel thread, set `current_thread_info'
* and stackptr in new task
*/
childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
childregs->gpr[10] = (unsigned long)task_thread_info(p);
} else {
childregs->sp = usp;
}
childregs->gpr[11] = 0; /* Result from fork() */
/*
* The way this works is that at some point in the future
* some task will call _switch to switch to the new task.
* That will pop off the stack frame created below and start
* the new task running at ret_from_fork. The new task will
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
/* redzone */
sp -= STACK_FRAME_OVERHEAD;
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *)sp;
ti = task_thread_info(p);
ti->ksp = sp;
/* kregs->sp must store the location of the 'pre-switch' kernel stack
* pointer... for a newly forked process, this is simply the top of
* the kernel stack.
*/
kregs->sp = top_of_kernel_stack;
kregs->gpr[3] = (unsigned long)current; /* arg to schedule_tail */
kregs->gpr[10] = (unsigned long)task_thread_info(p);
kregs->gpr[9] = (unsigned long)ret_from_fork;
return 0;
}
/*
* Set up a thread for executing a new program
*/
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
unsigned long sr = regs->sr & ~SPR_SR_SM;
set_fs(USER_DS);
memset(regs->gpr, 0, sizeof(regs->gpr));
regs->pc = pc;
regs->sr = sr;
regs->sp = sp;
/* printk("start thread, ksp = %lx\n", current_thread_info()->ksp);*/
}
/* Fill in the fpu structure for a core dump. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
{
/* TODO */
return 0;
}
extern struct thread_info *_switch(struct thread_info *old_ti,
struct thread_info *new_ti);
struct task_struct *__switch_to(struct task_struct *old,
struct task_struct *new)
{
struct task_struct *last;
struct thread_info *new_ti, *old_ti;
unsigned long flags;
local_irq_save(flags);
/* current_set is an array of saved current pointers
* (one for each cpu). we need them at user->kernel transition,
* while we save them at kernel->user transition
*/
new_ti = new->stack;
old_ti = old->stack;
current_thread_info_set[smp_processor_id()] = new_ti;
last = (_switch(old_ti, new_ti))->task;
local_irq_restore(flags);
return last;
}
/*
* Write out registers in core dump format, as defined by the
* struct user_regs_struct
*/
void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
{
dest[0] = 0; /* r0 */
memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
dest[32] = regs->pc;
dest[33] = regs->sr;
dest[34] = 0;
dest[35] = 0;
}
extern void _kernel_thread_helper(void);
void __noreturn kernel_thread_helper(int (*fn) (void *), void *arg)
{
do_exit(fn(arg));
}
/*
* Create a kernel thread.
*/
int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(®s, 0, sizeof(regs));
regs.gpr[20] = (unsigned long)fn;
regs.gpr[22] = (unsigned long)arg;
regs.sr = mfspr(SPR_SR);
regs.pc = (unsigned long)_kernel_thread_helper;
return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
0, ®s, 0, NULL, NULL);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage long _sys_execve(const char __user *name,
const char __user * const __user *argv,
const char __user * const __user *envp,
struct pt_regs *regs)
{
int 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;
}
unsigned long get_wchan(struct task_struct *p)
{
/* TODO */
return 0;
}
int kernel_execve(const char *filename, char *const argv[], char *const envp[])
{
register long __res asm("r11") = __NR_execve;
register long __a asm("r3") = (long)(filename);
register long __b asm("r4") = (long)(argv);
register long __c asm("r5") = (long)(envp);
__asm__ volatile ("l.sys 1"
: "=r" (__res), "=r"(__a), "=r"(__b), "=r"(__c)
: "0"(__res), "1"(__a), "2"(__b), "3"(__c)
: "r6", "r7", "r8", "r12", "r13", "r15",
"r17", "r19", "r21", "r23", "r25", "r27",
"r29", "r31");
__asm__ volatile ("l.nop");
return __res;
}