2 * arch/s390/kernel/process.c
5 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
10 * Derived from "arch/i386/kernel/process.c"
11 * Copyright (C) 1995, Linus Torvalds
15 * This file handles the architecture-dependent parts of process handling..
18 #include <linux/config.h>
19 #include <linux/compiler.h>
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
24 #include <linux/smp.h>
25 #include <linux/smp_lock.h>
26 #include <linux/stddef.h>
27 #include <linux/unistd.h>
28 #include <linux/ptrace.h>
29 #include <linux/slab.h>
30 #include <linux/vmalloc.h>
31 #include <linux/user.h>
32 #include <linux/a.out.h>
33 #include <linux/interrupt.h>
34 #include <linux/delay.h>
35 #include <linux/reboot.h>
36 #include <linux/init.h>
38 #include <asm/uaccess.h>
39 #include <asm/pgtable.h>
40 #include <asm/system.h>
42 #include <asm/processor.h>
44 #if defined(CONFIG_VIRT_TIMER) || defined (CONFIG_NO_IDLE_HZ)
45 #include <asm/timer.h>
48 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
51 * Return saved PC of a blocked thread. used in kernel/sched.
52 * resume in entry.S does not create a new stack frame, it
53 * just stores the registers %r6-%r15 to the frame given by
54 * schedule. We want to return the address of the caller of
55 * schedule, so we have to walk the backchain one time to
56 * find the frame schedule() store its return address.
58 unsigned long thread_saved_pc(struct task_struct *tsk)
62 bc = *((unsigned long *) tsk->thread.ksp);
63 #ifndef CONFIG_ARCH_S390X
64 return *((unsigned long *) (bc+56));
66 return *((unsigned long *) (bc+112));
71 * The idle loop on a S390...
74 void default_idle(void)
86 #if defined(CONFIG_VIRT_TIMER) || defined (CONFIG_NO_IDLE_HZ)
88 * hook to stop timers that should not tick while CPU is idle
97 * Wait for external, I/O or machine check interrupt and
98 * switch off machine check bit after the wait has ended.
100 wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
101 PSW_MASK_IO | PSW_MASK_EXT;
102 #ifndef CONFIG_ARCH_S390X
105 "0: la %0,1f-0b(%0)\n"
109 "1: la %0,2f-1b(%0)\n"
115 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
116 #else /* CONFIG_ARCH_S390X */
126 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
127 #endif /* CONFIG_ARCH_S390X */
137 void show_regs(struct pt_regs *regs)
139 struct task_struct *tsk = current;
141 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
142 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
143 current->comm, current->pid, (void *) tsk,
144 (void *) tsk->thread.ksp);
146 show_registers(regs);
147 /* Show stack backtrace if pt_regs is from kernel mode */
148 if (!(regs->psw.mask & PSW_MASK_PSTATE))
149 show_trace(0,(unsigned long *) regs->gprs[15]);
152 extern void kernel_thread_starter(void);
154 #ifndef CONFIG_ARCH_S390X
157 "kernel_thread_starter:\n"
166 #else /* CONFIG_ARCH_S390X */
169 "kernel_thread_starter:\n"
178 #endif /* CONFIG_ARCH_S390X */
180 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
184 memset(®s, 0, sizeof(regs));
185 regs.psw.mask = PSW_KERNEL_BITS;
186 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
187 regs.gprs[7] = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
188 regs.gprs[8] = __LC_KERNEL_STACK;
189 regs.gprs[9] = (unsigned long) fn;
190 regs.gprs[10] = (unsigned long) arg;
191 regs.gprs[11] = (unsigned long) do_exit;
194 /* Ok, create the new process.. */
195 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
196 0, ®s, 0, NULL, NULL);
200 * Free current thread data structures etc..
202 void exit_thread(void)
206 void flush_thread(void)
209 current->used_math = 0;
210 clear_tsk_thread_flag(current, TIF_USEDFPU);
213 void release_thread(struct task_struct *dead_task)
217 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
218 unsigned long unused,
219 struct task_struct * p, struct pt_regs * regs)
223 unsigned long back_chain;
227 unsigned long scratch[2];
228 unsigned long gprs[10]; /* gprs 6 -15 */
229 unsigned int fprs[4]; /* fpr 4 and 6 */
230 unsigned int empty[4];
231 struct pt_regs childregs;
234 frame = ((struct stack_frame *)
235 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
236 p->thread.ksp = (unsigned long) frame;
237 p->set_child_tid = p->clear_child_tid = NULL;
238 /* Store access registers to kernel stack of new process. */
239 frame->childregs = *regs;
240 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
241 frame->childregs.gprs[15] = new_stackp;
242 frame->back_chain = frame->eos = 0;
244 /* new return point is ret_from_fork */
245 frame->gprs[8] = (unsigned long) ret_from_fork;
247 /* fake return stack for resume(), don't go back to schedule */
248 frame->gprs[9] = (unsigned long) frame;
250 /* Save access registers to new thread structure. */
251 save_access_regs(&p->thread.acrs[0]);
253 #ifndef CONFIG_ARCH_S390X
255 * save fprs to current->thread.fp_regs to merge them with
256 * the emulated registers and then copy the result to the child.
258 save_fp_regs(¤t->thread.fp_regs);
259 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
260 sizeof(s390_fp_regs));
261 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
262 /* Set a new TLS ? */
263 if (clone_flags & CLONE_SETTLS)
264 p->thread.acrs[0] = regs->gprs[6];
265 #else /* CONFIG_ARCH_S390X */
266 /* Save the fpu registers to new thread structure. */
267 save_fp_regs(&p->thread.fp_regs);
268 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
269 /* Set a new TLS ? */
270 if (clone_flags & CLONE_SETTLS) {
271 if (test_thread_flag(TIF_31BIT)) {
272 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
274 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
275 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
278 #endif /* CONFIG_ARCH_S390X */
279 /* start new process with ar4 pointing to the correct address space */
280 p->thread.mm_segment = get_fs();
281 /* Don't copy debug registers */
282 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
287 asmlinkage long sys_fork(struct pt_regs regs)
289 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL);
292 asmlinkage long sys_clone(struct pt_regs regs)
294 unsigned long clone_flags;
296 int __user *parent_tidptr, *child_tidptr;
298 clone_flags = regs.gprs[3];
299 newsp = regs.orig_gpr2;
300 parent_tidptr = (int __user *) regs.gprs[4];
301 child_tidptr = (int __user *) regs.gprs[5];
303 newsp = regs.gprs[15];
304 return do_fork(clone_flags & ~CLONE_IDLETASK, newsp, ®s, 0,
305 parent_tidptr, child_tidptr);
309 * This is trivial, and on the face of it looks like it
310 * could equally well be done in user mode.
312 * Not so, for quite unobvious reasons - register pressure.
313 * In user mode vfork() cannot have a stack frame, and if
314 * done by calling the "clone()" system call directly, you
315 * do not have enough call-clobbered registers to hold all
316 * the information you need.
318 asmlinkage long sys_vfork(struct pt_regs regs)
320 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
321 regs.gprs[15], ®s, 0, NULL, NULL);
325 * sys_execve() executes a new program.
327 asmlinkage long sys_execve(struct pt_regs regs)
332 filename = getname((char __user *) regs.orig_gpr2);
333 error = PTR_ERR(filename);
334 if (IS_ERR(filename))
336 error = do_execve(filename, (char __user * __user *) regs.gprs[3],
337 (char __user * __user *) regs.gprs[4], ®s);
339 current->ptrace &= ~PT_DTRACE;
340 current->thread.fp_regs.fpc = 0;
341 if (MACHINE_HAS_IEEE)
342 asm volatile("sfpc %0,%0" : : "d" (0));
351 * fill in the FPU structure for a core dump.
353 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
355 #ifndef CONFIG_ARCH_S390X
357 * save fprs to current->thread.fp_regs to merge them with
358 * the emulated registers and then copy the result to the dump.
360 save_fp_regs(¤t->thread.fp_regs);
361 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
362 #else /* CONFIG_ARCH_S390X */
363 save_fp_regs(fpregs);
364 #endif /* CONFIG_ARCH_S390X */
369 * fill in the user structure for a core dump..
371 void dump_thread(struct pt_regs * regs, struct user * dump)
374 /* changed the size calculations - should hopefully work better. lbt */
375 dump->magic = CMAGIC;
376 dump->start_code = 0;
377 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
378 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
379 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
380 dump->u_dsize -= dump->u_tsize;
382 if (dump->start_stack < TASK_SIZE)
383 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
384 memcpy(&dump->regs, regs, sizeof(s390_regs));
385 dump_fpu (regs, &dump->regs.fp_regs);
386 dump->regs.per_info = current->thread.per_info;
389 unsigned long get_wchan(struct task_struct *p)
391 unsigned long r14, r15, bc;
392 unsigned long stack_page;
394 if (!p || p == current || p->state == TASK_RUNNING)
396 stack_page = (unsigned long) p->thread_info;
398 if (!stack_page || r15 < stack_page ||
399 r15 >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
401 bc = (*(unsigned long *) r15) & PSW_ADDR_INSN;
403 if (bc < stack_page ||
404 bc >= THREAD_SIZE - sizeof(unsigned long) + stack_page)
406 #ifndef CONFIG_ARCH_S390X
407 r14 = (*(unsigned long *) (bc+56)) & PSW_ADDR_INSN;
409 r14 = *(unsigned long *) (bc+112);
411 if (!in_sched_functions(r14))
413 bc = (*(unsigned long *) bc) & PSW_ADDR_INSN;
414 } while (count++ < 16);