[TG3]: Set minimal hw interrupt mitigation.
[linux-2.6/verdex.git] / arch / s390 / kernel / process.c
blob7aea25d6e3003744758cc62542b56e3a5a8ef2c8
1 /*
2 * arch/s390/kernel/process.c
4 * S390 version
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/cpu.h>
21 #include <linux/errno.h>
22 #include <linux/sched.h>
23 #include <linux/kernel.h>
24 #include <linux/mm.h>
25 #include <linux/smp.h>
26 #include <linux/smp_lock.h>
27 #include <linux/stddef.h>
28 #include <linux/unistd.h>
29 #include <linux/ptrace.h>
30 #include <linux/slab.h>
31 #include <linux/vmalloc.h>
32 #include <linux/user.h>
33 #include <linux/a.out.h>
34 #include <linux/interrupt.h>
35 #include <linux/delay.h>
36 #include <linux/reboot.h>
37 #include <linux/init.h>
38 #include <linux/module.h>
39 #include <linux/notifier.h>
41 #include <asm/uaccess.h>
42 #include <asm/pgtable.h>
43 #include <asm/system.h>
44 #include <asm/io.h>
45 #include <asm/processor.h>
46 #include <asm/irq.h>
47 #include <asm/timer.h>
49 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
52 * Return saved PC of a blocked thread. used in kernel/sched.
53 * resume in entry.S does not create a new stack frame, it
54 * just stores the registers %r6-%r15 to the frame given by
55 * schedule. We want to return the address of the caller of
56 * schedule, so we have to walk the backchain one time to
57 * find the frame schedule() store its return address.
59 unsigned long thread_saved_pc(struct task_struct *tsk)
61 struct stack_frame *sf;
63 sf = (struct stack_frame *) tsk->thread.ksp;
64 sf = (struct stack_frame *) sf->back_chain;
65 return sf->gprs[8];
69 * Need to know about CPUs going idle?
71 static struct notifier_block *idle_chain;
73 int register_idle_notifier(struct notifier_block *nb)
75 return notifier_chain_register(&idle_chain, nb);
77 EXPORT_SYMBOL(register_idle_notifier);
79 int unregister_idle_notifier(struct notifier_block *nb)
81 return notifier_chain_unregister(&idle_chain, nb);
83 EXPORT_SYMBOL(unregister_idle_notifier);
85 void do_monitor_call(struct pt_regs *regs, long interruption_code)
87 /* disable monitor call class 0 */
88 __ctl_clear_bit(8, 15);
90 notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
91 (void *)(long) smp_processor_id());
95 * The idle loop on a S390...
97 void default_idle(void)
99 psw_t wait_psw;
100 unsigned long reg;
101 int cpu, rc;
103 local_irq_disable();
104 if (need_resched()) {
105 local_irq_enable();
106 schedule();
107 return;
110 /* CPU is going idle. */
111 cpu = smp_processor_id();
112 rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
113 if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
114 BUG();
115 if (rc != NOTIFY_OK) {
116 local_irq_enable();
117 return;
120 /* enable monitor call class 0 */
121 __ctl_set_bit(8, 15);
123 #ifdef CONFIG_HOTPLUG_CPU
124 if (cpu_is_offline(smp_processor_id()))
125 cpu_die();
126 #endif
129 * Wait for external, I/O or machine check interrupt and
130 * switch off machine check bit after the wait has ended.
132 wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
133 PSW_MASK_IO | PSW_MASK_EXT;
134 #ifndef CONFIG_ARCH_S390X
135 asm volatile (
136 " basr %0,0\n"
137 "0: la %0,1f-0b(%0)\n"
138 " st %0,4(%1)\n"
139 " oi 4(%1),0x80\n"
140 " lpsw 0(%1)\n"
141 "1: la %0,2f-1b(%0)\n"
142 " st %0,4(%1)\n"
143 " oi 4(%1),0x80\n"
144 " ni 1(%1),0xf9\n"
145 " lpsw 0(%1)\n"
146 "2:"
147 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
148 #else /* CONFIG_ARCH_S390X */
149 asm volatile (
150 " larl %0,0f\n"
151 " stg %0,8(%1)\n"
152 " lpswe 0(%1)\n"
153 "0: larl %0,1f\n"
154 " stg %0,8(%1)\n"
155 " ni 1(%1),0xf9\n"
156 " lpswe 0(%1)\n"
157 "1:"
158 : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
159 #endif /* CONFIG_ARCH_S390X */
162 void cpu_idle(void)
164 for (;;)
165 default_idle();
168 void show_regs(struct pt_regs *regs)
170 struct task_struct *tsk = current;
172 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
173 printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
174 current->comm, current->pid, (void *) tsk,
175 (void *) tsk->thread.ksp);
177 show_registers(regs);
178 /* Show stack backtrace if pt_regs is from kernel mode */
179 if (!(regs->psw.mask & PSW_MASK_PSTATE))
180 show_trace(0,(unsigned long *) regs->gprs[15]);
183 extern void kernel_thread_starter(void);
185 __asm__(".align 4\n"
186 "kernel_thread_starter:\n"
187 " la 2,0(10)\n"
188 " basr 14,9\n"
189 " la 2,0\n"
190 " br 11\n");
192 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
194 struct pt_regs regs;
196 memset(&regs, 0, sizeof(regs));
197 regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
198 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
199 regs.gprs[9] = (unsigned long) fn;
200 regs.gprs[10] = (unsigned long) arg;
201 regs.gprs[11] = (unsigned long) do_exit;
202 regs.orig_gpr2 = -1;
204 /* Ok, create the new process.. */
205 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
206 0, &regs, 0, NULL, NULL);
210 * Free current thread data structures etc..
212 void exit_thread(void)
216 void flush_thread(void)
218 clear_used_math();
219 clear_tsk_thread_flag(current, TIF_USEDFPU);
222 void release_thread(struct task_struct *dead_task)
226 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
227 unsigned long unused,
228 struct task_struct * p, struct pt_regs * regs)
230 struct fake_frame
232 struct stack_frame sf;
233 struct pt_regs childregs;
234 } *frame;
236 frame = ((struct fake_frame *)
237 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
238 p->thread.ksp = (unsigned long) frame;
239 /* Store access registers to kernel stack of new process. */
240 frame->childregs = *regs;
241 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
242 frame->childregs.gprs[15] = new_stackp;
243 frame->sf.back_chain = 0;
245 /* new return point is ret_from_fork */
246 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
248 /* fake return stack for resume(), don't go back to schedule */
249 frame->sf.gprs[9] = (unsigned long) frame;
251 /* Save access registers to new thread structure. */
252 save_access_regs(&p->thread.acrs[0]);
254 #ifndef CONFIG_ARCH_S390X
256 * save fprs to current->thread.fp_regs to merge them with
257 * the emulated registers and then copy the result to the child.
259 save_fp_regs(&current->thread.fp_regs);
260 memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
261 sizeof(s390_fp_regs));
262 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
263 /* Set a new TLS ? */
264 if (clone_flags & CLONE_SETTLS)
265 p->thread.acrs[0] = regs->gprs[6];
266 #else /* CONFIG_ARCH_S390X */
267 /* Save the fpu registers to new thread structure. */
268 save_fp_regs(&p->thread.fp_regs);
269 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
270 /* Set a new TLS ? */
271 if (clone_flags & CLONE_SETTLS) {
272 if (test_thread_flag(TIF_31BIT)) {
273 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
274 } else {
275 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
276 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
279 #endif /* CONFIG_ARCH_S390X */
280 /* start new process with ar4 pointing to the correct address space */
281 p->thread.mm_segment = get_fs();
282 /* Don't copy debug registers */
283 memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
285 return 0;
288 asmlinkage long sys_fork(struct pt_regs regs)
290 return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
293 asmlinkage long sys_clone(struct pt_regs regs)
295 unsigned long clone_flags;
296 unsigned long newsp;
297 int __user *parent_tidptr, *child_tidptr;
299 clone_flags = regs.gprs[3];
300 newsp = regs.orig_gpr2;
301 parent_tidptr = (int __user *) regs.gprs[4];
302 child_tidptr = (int __user *) regs.gprs[5];
303 if (!newsp)
304 newsp = regs.gprs[15];
305 return do_fork(clone_flags, newsp, &regs, 0,
306 parent_tidptr, child_tidptr);
310 * This is trivial, and on the face of it looks like it
311 * could equally well be done in user mode.
313 * Not so, for quite unobvious reasons - register pressure.
314 * In user mode vfork() cannot have a stack frame, and if
315 * done by calling the "clone()" system call directly, you
316 * do not have enough call-clobbered registers to hold all
317 * the information you need.
319 asmlinkage long sys_vfork(struct pt_regs regs)
321 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
322 regs.gprs[15], &regs, 0, NULL, NULL);
326 * sys_execve() executes a new program.
328 asmlinkage long sys_execve(struct pt_regs regs)
330 int error;
331 char * filename;
333 filename = getname((char __user *) regs.orig_gpr2);
334 error = PTR_ERR(filename);
335 if (IS_ERR(filename))
336 goto out;
337 error = do_execve(filename, (char __user * __user *) regs.gprs[3],
338 (char __user * __user *) regs.gprs[4], &regs);
339 if (error == 0) {
340 task_lock(current);
341 current->ptrace &= ~PT_DTRACE;
342 task_unlock(current);
343 current->thread.fp_regs.fpc = 0;
344 if (MACHINE_HAS_IEEE)
345 asm volatile("sfpc %0,%0" : : "d" (0));
347 putname(filename);
348 out:
349 return error;
354 * fill in the FPU structure for a core dump.
356 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
358 #ifndef CONFIG_ARCH_S390X
360 * save fprs to current->thread.fp_regs to merge them with
361 * the emulated registers and then copy the result to the dump.
363 save_fp_regs(&current->thread.fp_regs);
364 memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
365 #else /* CONFIG_ARCH_S390X */
366 save_fp_regs(fpregs);
367 #endif /* CONFIG_ARCH_S390X */
368 return 1;
372 * fill in the user structure for a core dump..
374 void dump_thread(struct pt_regs * regs, struct user * dump)
377 /* changed the size calculations - should hopefully work better. lbt */
378 dump->magic = CMAGIC;
379 dump->start_code = 0;
380 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
381 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
382 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
383 dump->u_dsize -= dump->u_tsize;
384 dump->u_ssize = 0;
385 if (dump->start_stack < TASK_SIZE)
386 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
387 memcpy(&dump->regs, regs, sizeof(s390_regs));
388 dump_fpu (regs, &dump->regs.fp_regs);
389 dump->regs.per_info = current->thread.per_info;
392 unsigned long get_wchan(struct task_struct *p)
394 struct stack_frame *sf, *low, *high;
395 unsigned long return_address;
396 int count;
398 if (!p || p == current || p->state == TASK_RUNNING || !p->thread_info)
399 return 0;
400 low = (struct stack_frame *) p->thread_info;
401 high = (struct stack_frame *)
402 ((unsigned long) p->thread_info + THREAD_SIZE) - 1;
403 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
404 if (sf <= low || sf > high)
405 return 0;
406 for (count = 0; count < 16; count++) {
407 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
408 if (sf <= low || sf > high)
409 return 0;
410 return_address = sf->gprs[8] & PSW_ADDR_INSN;
411 if (!in_sched_functions(return_address))
412 return return_address;
414 return 0;