blob: 4a0f5a1551eadcf021d6ecf317a1e61e0ef07dea [file] [log] [blame]
/*
* arch/s390/kernel/process.c
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Hartmut Penner (hp@de.ibm.com),
* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
*
* Derived from "arch/i386/kernel/process.c"
* Copyright (C) 1995, Linus Torvalds
*/
/*
* This file handles the architecture-dependent parts of process handling..
*/
#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/timer.h>
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
/*
* Return saved PC of a blocked thread. used in kernel/sched.
* resume in entry.S does not create a new stack frame, it
* just stores the registers %r6-%r15 to the frame given by
* schedule. We want to return the address of the caller of
* schedule, so we have to walk the backchain one time to
* find the frame schedule() store its return address.
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
struct stack_frame *sf, *low, *high;
if (!tsk || !task_stack_page(tsk))
return 0;
low = task_stack_page(tsk);
high = (struct stack_frame *) task_pt_regs(tsk);
sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
return sf->gprs[8];
}
/*
* Need to know about CPUs going idle?
*/
static ATOMIC_NOTIFIER_HEAD(idle_chain);
int register_idle_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&idle_chain, nb);
}
EXPORT_SYMBOL(register_idle_notifier);
int unregister_idle_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&idle_chain, nb);
}
EXPORT_SYMBOL(unregister_idle_notifier);
void do_monitor_call(struct pt_regs *regs, long interruption_code)
{
/* disable monitor call class 0 */
__ctl_clear_bit(8, 15);
atomic_notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
(void *)(long) smp_processor_id());
}
extern void s390_handle_mcck(void);
/*
* The idle loop on a S390...
*/
static void default_idle(void)
{
int cpu, rc;
/* CPU is going idle. */
cpu = smp_processor_id();
local_irq_disable();
if (need_resched()) {
local_irq_enable();
return;
}
rc = atomic_notifier_call_chain(&idle_chain,
CPU_IDLE, (void *)(long) cpu);
if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
BUG();
if (rc != NOTIFY_OK) {
local_irq_enable();
return;
}
/* enable monitor call class 0 */
__ctl_set_bit(8, 15);
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(cpu)) {
preempt_enable_no_resched();
cpu_die();
}
#endif
local_mcck_disable();
if (test_thread_flag(TIF_MCCK_PENDING)) {
local_mcck_enable();
local_irq_enable();
s390_handle_mcck();
return;
}
/* Wait for external, I/O or machine check interrupt. */
__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_WAIT |
PSW_MASK_IO | PSW_MASK_EXT);
}
void cpu_idle(void)
{
for (;;) {
while (!need_resched())
default_idle();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
void show_regs(struct pt_regs *regs)
{
struct task_struct *tsk = current;
printk("CPU: %d %s\n", task_thread_info(tsk)->cpu, print_tainted());
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
current->comm, current->pid, (void *) tsk,
(void *) tsk->thread.ksp);
show_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!(regs->psw.mask & PSW_MASK_PSTATE))
show_trace(0,(unsigned long *) regs->gprs[15]);
}
extern void kernel_thread_starter(void);
__asm__(".align 4\n"
"kernel_thread_starter:\n"
" la 2,0(10)\n"
" basr 14,9\n"
" la 2,0\n"
" br 11\n");
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
regs.gprs[9] = (unsigned long) fn;
regs.gprs[10] = (unsigned long) arg;
regs.gprs[11] = (unsigned long) do_exit;
regs.orig_gpr2 = -1;
/* Ok, create the new process.. */
return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
0, &regs, 0, NULL, NULL);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
void flush_thread(void)
{
clear_used_math();
clear_tsk_thread_flag(current, TIF_USEDFPU);
}
void release_thread(struct task_struct *dead_task)
{
}
int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
unsigned long unused,
struct task_struct * p, struct pt_regs * regs)
{
struct fake_frame
{
struct stack_frame sf;
struct pt_regs childregs;
} *frame;
frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
p->thread.ksp = (unsigned long) frame;
/* Store access registers to kernel stack of new process. */
frame->childregs = *regs;
frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
frame->childregs.gprs[15] = new_stackp;
frame->sf.back_chain = 0;
/* new return point is ret_from_fork */
frame->sf.gprs[8] = (unsigned long) ret_from_fork;
/* fake return stack for resume(), don't go back to schedule */
frame->sf.gprs[9] = (unsigned long) frame;
/* Save access registers to new thread structure. */
save_access_regs(&p->thread.acrs[0]);
#ifndef CONFIG_64BIT
/*
* save fprs to current->thread.fp_regs to merge them with
* the emulated registers and then copy the result to the child.
*/
save_fp_regs(&current->thread.fp_regs);
memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
sizeof(s390_fp_regs));
p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
/* Set a new TLS ? */
if (clone_flags & CLONE_SETTLS)
p->thread.acrs[0] = regs->gprs[6];
#else /* CONFIG_64BIT */
/* Save the fpu registers to new thread structure. */
save_fp_regs(&p->thread.fp_regs);
p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
/* Set a new TLS ? */
if (clone_flags & CLONE_SETTLS) {
if (test_thread_flag(TIF_31BIT)) {
p->thread.acrs[0] = (unsigned int) regs->gprs[6];
} else {
p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
p->thread.acrs[1] = (unsigned int) regs->gprs[6];
}
}
#endif /* CONFIG_64BIT */
/* start new process with ar4 pointing to the correct address space */
p->thread.mm_segment = get_fs();
/* Don't copy debug registers */
memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
return 0;
}
asmlinkage long sys_fork(struct pt_regs regs)
{
return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
}
asmlinkage long sys_clone(struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
int __user *parent_tidptr, *child_tidptr;
clone_flags = regs.gprs[3];
newsp = regs.orig_gpr2;
parent_tidptr = (int __user *) regs.gprs[4];
child_tidptr = (int __user *) regs.gprs[5];
if (!newsp)
newsp = regs.gprs[15];
return do_fork(clone_flags, newsp, &regs, 0,
parent_tidptr, child_tidptr);
}
/*
* This is trivial, and on the face of it looks like it
* could equally well be done in user mode.
*
* Not so, for quite unobvious reasons - register pressure.
* In user mode vfork() cannot have a stack frame, and if
* done by calling the "clone()" system call directly, you
* do not have enough call-clobbered registers to hold all
* the information you need.
*/
asmlinkage long sys_vfork(struct pt_regs regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
regs.gprs[15], &regs, 0, NULL, NULL);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage long sys_execve(struct pt_regs regs)
{
int error;
char * filename;
filename = getname((char __user *) regs.orig_gpr2);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename, (char __user * __user *) regs.gprs[3],
(char __user * __user *) regs.gprs[4], &regs);
if (error == 0) {
task_lock(current);
current->ptrace &= ~PT_DTRACE;
task_unlock(current);
current->thread.fp_regs.fpc = 0;
if (MACHINE_HAS_IEEE)
asm volatile("sfpc %0,%0" : : "d" (0));
}
putname(filename);
out:
return error;
}
/*
* fill in the FPU structure for a core dump.
*/
int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
{
#ifndef CONFIG_64BIT
/*
* save fprs to current->thread.fp_regs to merge them with
* the emulated registers and then copy the result to the dump.
*/
save_fp_regs(&current->thread.fp_regs);
memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
#else /* CONFIG_64BIT */
save_fp_regs(fpregs);
#endif /* CONFIG_64BIT */
return 1;
}
unsigned long get_wchan(struct task_struct *p)
{
struct stack_frame *sf, *low, *high;
unsigned long return_address;
int count;
if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
return 0;
low = task_stack_page(p);
high = (struct stack_frame *) task_pt_regs(p);
sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
for (count = 0; count < 16; count++) {
sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
if (sf <= low || sf > high)
return 0;
return_address = sf->gprs[8] & PSW_ADDR_INSN;
if (!in_sched_functions(return_address))
return return_address;
}
return 0;
}