/*
* 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;
sf = (struct stack_frame *) tsk->thread.ksp;
sf = (struct stack_frame *) sf->back_chain;
return sf->gprs[8];
}
/*
* Need to know about CPUs going idle?
*/
static struct notifier_block *idle_chain;
int register_idle_notifier(struct notifier_block *nb)
{
return notifier_chain_register(&idle_chain, nb);
}
EXPORT_SYMBOL(register_idle_notifier);
int unregister_idle_notifier(struct notifier_block *nb)
{
return 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);
notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
(void *)(long) smp_processor_id());
}
/*
* The idle loop on a S390...
*/
void default_idle(void)
{
psw_t wait_psw;
unsigned long reg;
int cpu, rc;
local_irq_disable();
if (need_resched()) {
local_irq_enable();
schedule();
return;
}
/* CPU is going idle. */
cpu = smp_processor_id();
rc = 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(smp_processor_id()))
cpu_die();
#endif
/*
* Wait for external, I/O or machine check interrupt and
* switch off machine check bit after the wait has ended.
*/
wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
PSW_MASK_IO | PSW_MASK_EXT;
#ifndef CONFIG_ARCH_S390X
asm volatile (
" basr %0,0\n"
"0: la %0,1f-0b(%0)\n"
" st %0,4(%1)\n"
" oi 4(%1),0x80\n"
" lpsw 0(%1)\n"
"1: la %0,2f-1b(%0)\n"
" st %0,4(%1)\n"
" oi 4(%1),0x80\n"
" ni 1(%1),0xf9\n"
" lpsw 0(%1)\n"
"2:"
: "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
#else /* CONFIG_ARCH_S390X */
asm volatile (
" larl %0,0f\n"
" stg %0,8(%1)\n"
" lpswe 0(%1)\n"
"0: larl %0,1f\n"
" stg %0,8(%1)\n"
" ni 1(%1),0xf9\n"
" lpswe 0(%1)\n"
"1:"
: "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
#endif /* CONFIG_ARCH_S390X */
}
void cpu_idle(void)
{
for (;;)
default_idle();
}
void show_regs(struct pt_regs *regs)
{
struct task_struct *tsk = current;
printk("CPU: %d %s\n", tsk->thread_info->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(®s, 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, ®s, 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 = ((struct fake_frame *)
(THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
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_ARCH_S390X
/*
* 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(¤t->thread.fp_regs);
memcpy(&p->thread.fp_regs, ¤t->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_ARCH_S390X */
/* 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_ARCH_S390X */
/* 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], ®s, 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, ®s, 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], ®s, 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], ®s);
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_ARCH_S390X
/*
* 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(¤t->thread.fp_regs);
memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
#else /* CONFIG_ARCH_S390X */
save_fp_regs(fpregs);
#endif /* CONFIG_ARCH_S390X */
return 1;
}
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs * regs, struct user * dump)
{
/* changed the size calculations - should hopefully work better. lbt */
dump->magic = CMAGIC;
dump->start_code = 0;
dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
dump->u_dsize -= dump->u_tsize;
dump->u_ssize = 0;
if (dump->start_stack < TASK_SIZE)
dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
memcpy(&dump->regs, regs, sizeof(s390_regs));
dump_fpu (regs, &dump->regs.fp_regs);
dump->regs.per_info = current->thread.per_info;
}
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 || !p->thread_info)
return 0;
low = (struct stack_frame *) p->thread_info;
high = (struct stack_frame *)
((unsigned long) p->thread_info + THREAD_SIZE) - 1;
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;
}
