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/*
* 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..
*/
#define __KERNEL_SYSCALLS__
#include <stdarg.h>
#include <linux/config.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 <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/irq.h>
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
/*
* The idle loop on a S390...
*/
static psw_t wait_psw;
int cpu_idle(void *unused)
{
/* endless idle loop with no priority at all */
init_idle();
current->nice = 20;
current->counter = -100;
wait_psw.mask = _WAIT_PSW_MASK;
wait_psw.addr = (unsigned long) &&idle_wakeup;
while(1) {
if (current->need_resched) {
schedule();
check_pgt_cache();
continue;
}
/* load wait psw */
asm volatile (
"lpswe %0"
: : "m" (wait_psw) );
idle_wakeup:
}
}
extern void show_registers(struct pt_regs *regs);
extern void show_trace(unsigned long *sp);
void show_regs(struct pt_regs *regs)
{
struct task_struct *tsk = current;
printk("CPU: %d %s\n", tsk->processor, print_tainted());
printk("Process %s (pid: %d, task: %016lx, ksp: %016lx)\n",
current->comm, current->pid, (unsigned long) tsk,
tsk->thread.ksp);
show_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!(regs->psw.mask & PSW_PROBLEM_STATE))
show_trace((unsigned long *) regs->gprs[15]);
}
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
int clone_arg = flags | CLONE_VM;
int retval;
__asm__ __volatile__(
" slgr 2,2\n"
" lgr 3,%1\n"
" lg 4,%6\n" /* load kernel stack ptr of parent */
" svc %b2\n" /* Linux system call*/
" clg 4,%6\n" /* compare ksp's: child or parent ? */
" je 0f\n" /* parent - jump*/
" lg 15,%6\n" /* fix kernel stack pointer*/
" aghi 15,%7\n"
" xc 0(160,15),0(15)\n" /* clear save area */
" lgr 2,%4\n" /* load argument*/
" basr 14,%5\n" /* call fn*/
" svc %b3\n" /* Linux system call*/
"0: lgr %0,2"
: "=a" (retval)
: "d" (clone_arg), "i" (__NR_clone), "i" (__NR_exit),
"d" (arg), "a" (fn), "i" (__LC_KERNEL_STACK) ,
"i" (-STACK_FRAME_OVERHEAD)
: "2", "3", "4" );
return retval;
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
void flush_thread(void)
{
current->used_math = 0;
current->flags &= ~PF_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 stack_frame
{
unsigned long back_chain;
unsigned long eos;
unsigned long glue1;
unsigned long glue2;
unsigned long scratch[2];
unsigned long gprs[10]; /* gprs 6 -15 */
unsigned long fprs[2]; /* fpr 4 and 6 */
unsigned long empty[2];
struct pt_regs childregs;
} *frame;
frame = (struct stack_frame *) (4*PAGE_SIZE + (unsigned long) p) -1;
p->thread.ksp = (unsigned long) frame;
frame->childregs = *regs;
frame->childregs.gprs[15] = new_stackp;
frame->back_chain = frame->eos = 0;
/* new return point is ret_from_sys_call */
frame->gprs[8] = (unsigned long) &ret_from_fork;
/* fake return stack for resume(), don't go back to schedule */
frame->gprs[9] = (unsigned long) frame;
frame->childregs.old_ilc = -1; /* We are not single stepping an svc */
/* save fprs, if used in last task */
save_fp_regs(&p->thread.fp_regs);
p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
/* Don't copy debug registers */
memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
return 0;
}
asmlinkage int sys_fork(struct pt_regs regs)
{
return do_fork(SIGCHLD, regs.gprs[15], ®s, 0);
}
asmlinkage int sys_clone(struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
clone_flags = regs.gprs[3];
newsp = regs.orig_gpr2;
if (!newsp)
newsp = regs.gprs[15];
return do_fork(clone_flags, newsp, ®s, 0);
}
/*
* 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 int sys_vfork(struct pt_regs regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
regs.gprs[15], ®s, 0);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(struct pt_regs regs)
{
int error;
char * filename;
filename = getname((char *) regs.orig_gpr2);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename, (char **) regs.gprs[3], (char **) regs.gprs[4], ®s);
if (error == 0)
{
current->ptrace &= ~PT_DTRACE;
current->thread.fp_regs.fpc=0;
__asm__ __volatile__
("sr 0,0\n\t"
"sfpc 0,0\n\t"
: : :"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)
{
save_fp_regs(fpregs);
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 = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
dump->u_dsize = ((unsigned long) (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 = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
memcpy(&dump->regs.gprs[0],regs,sizeof(s390_regs));
dump_fpu (regs, &dump->regs.fp_regs);
memcpy(&dump->regs.per_info,¤t->thread.per_info,sizeof(per_struct));
}
/*
* These bracket the sleeping functions..
*/
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched ((unsigned long) scheduling_functions_start_here)
#define last_sched ((unsigned long) scheduling_functions_end_here)
unsigned long get_wchan(struct task_struct *p)
{
unsigned long r14, r15, bc;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long) p;
r15 = p->thread.ksp;
if (!stack_page || r15 < stack_page || r15 >= 16380+stack_page)
return 0;
bc = *(unsigned long *) r15;
do {
if (bc < stack_page || bc >= 16380+stack_page)
return 0;
r14 = *(unsigned long *) (bc+112);
if (r14 < first_sched || r14 >= last_sched)
return r14;
bc = *(unsigned long *) bc;
} while (count++ < 16);
return 0;
}
#undef last_sched
#undef first_sched
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