1 /* 2 * arch/s390/kernel/process.c 3 * 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), 9 * 10 * Derived from "arch/i386/kernel/process.c" 11 * Copyright (C) 1995, Linus Torvalds 12 */ 13 14 /* 15 * This file handles the architecture-dependent parts of process handling.. 16 */ 17 18 #include <linux/compiler.h> 19 #include <linux/cpu.h> 20 #include <linux/errno.h> 21 #include <linux/sched.h> 22 #include <linux/kernel.h> 23 #include <linux/mm.h> 24 #include <linux/fs.h> 25 #include <linux/smp.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/interrupt.h> 33 #include <linux/delay.h> 34 #include <linux/reboot.h> 35 #include <linux/init.h> 36 #include <linux/module.h> 37 #include <linux/notifier.h> 38 #include <linux/utsname.h> 39 #include <asm/uaccess.h> 40 #include <asm/pgtable.h> 41 #include <asm/system.h> 42 #include <asm/io.h> 43 #include <asm/processor.h> 44 #include <asm/irq.h> 45 #include <asm/timer.h> 46 #include <asm/cpu.h> 47 48 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 49 50 /* 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. 57 */ 58 unsigned long thread_saved_pc(struct task_struct *tsk) 59 { 60 struct stack_frame *sf, *low, *high; 61 62 if (!tsk || !task_stack_page(tsk)) 63 return 0; 64 low = task_stack_page(tsk); 65 high = (struct stack_frame *) task_pt_regs(tsk); 66 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN); 67 if (sf <= low || sf > high) 68 return 0; 69 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 70 if (sf <= low || sf > high) 71 return 0; 72 return sf->gprs[8]; 73 } 74 75 /* 76 * Need to know about CPUs going idle? 77 */ 78 static ATOMIC_NOTIFIER_HEAD(idle_chain); 79 80 int register_idle_notifier(struct notifier_block *nb) 81 { 82 return atomic_notifier_chain_register(&idle_chain, nb); 83 } 84 EXPORT_SYMBOL(register_idle_notifier); 85 86 int unregister_idle_notifier(struct notifier_block *nb) 87 { 88 return atomic_notifier_chain_unregister(&idle_chain, nb); 89 } 90 EXPORT_SYMBOL(unregister_idle_notifier); 91 92 void do_monitor_call(struct pt_regs *regs, long interruption_code) 93 { 94 #ifdef CONFIG_SMP 95 struct s390_idle_data *idle; 96 97 idle = &__get_cpu_var(s390_idle); 98 spin_lock(&idle->lock); 99 idle->idle_time += get_clock() - idle->idle_enter; 100 idle->in_idle = 0; 101 spin_unlock(&idle->lock); 102 #endif 103 /* disable monitor call class 0 */ 104 __ctl_clear_bit(8, 15); 105 106 atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE, 107 (void *)(long) smp_processor_id()); 108 } 109 110 extern void s390_handle_mcck(void); 111 /* 112 * The idle loop on a S390... 113 */ 114 static void default_idle(void) 115 { 116 int cpu, rc; 117 int nr_calls = 0; 118 void *hcpu; 119 #ifdef CONFIG_SMP 120 struct s390_idle_data *idle; 121 #endif 122 123 /* CPU is going idle. */ 124 cpu = smp_processor_id(); 125 hcpu = (void *)(long)cpu; 126 local_irq_disable(); 127 if (need_resched()) { 128 local_irq_enable(); 129 return; 130 } 131 132 rc = __atomic_notifier_call_chain(&idle_chain, S390_CPU_IDLE, hcpu, -1, 133 &nr_calls); 134 if (rc == NOTIFY_BAD) { 135 nr_calls--; 136 __atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE, 137 hcpu, nr_calls, NULL); 138 local_irq_enable(); 139 return; 140 } 141 142 /* enable monitor call class 0 */ 143 __ctl_set_bit(8, 15); 144 145 #ifdef CONFIG_HOTPLUG_CPU 146 if (cpu_is_offline(cpu)) { 147 preempt_enable_no_resched(); 148 cpu_die(); 149 } 150 #endif 151 152 local_mcck_disable(); 153 if (test_thread_flag(TIF_MCCK_PENDING)) { 154 local_mcck_enable(); 155 /* disable monitor call class 0 */ 156 __ctl_clear_bit(8, 15); 157 atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE, 158 hcpu); 159 local_irq_enable(); 160 s390_handle_mcck(); 161 return; 162 } 163 #ifdef CONFIG_SMP 164 idle = &__get_cpu_var(s390_idle); 165 spin_lock(&idle->lock); 166 idle->idle_count++; 167 idle->in_idle = 1; 168 idle->idle_enter = get_clock(); 169 spin_unlock(&idle->lock); 170 #endif 171 trace_hardirqs_on(); 172 /* Wait for external, I/O or machine check interrupt. */ 173 __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT | 174 PSW_MASK_IO | PSW_MASK_EXT); 175 } 176 177 void cpu_idle(void) 178 { 179 for (;;) { 180 while (!need_resched()) 181 default_idle(); 182 183 preempt_enable_no_resched(); 184 schedule(); 185 preempt_disable(); 186 } 187 } 188 189 void show_regs(struct pt_regs *regs) 190 { 191 print_modules(); 192 printk("CPU: %d %s %s %.*s\n", 193 task_thread_info(current)->cpu, print_tainted(), 194 init_utsname()->release, 195 (int)strcspn(init_utsname()->version, " "), 196 init_utsname()->version); 197 printk("Process %s (pid: %d, task: %p, ksp: %p)\n", 198 current->comm, current->pid, current, 199 (void *) current->thread.ksp); 200 show_registers(regs); 201 /* Show stack backtrace if pt_regs is from kernel mode */ 202 if (!(regs->psw.mask & PSW_MASK_PSTATE)) 203 show_trace(NULL, (unsigned long *) regs->gprs[15]); 204 } 205 206 extern void kernel_thread_starter(void); 207 208 asm( 209 ".align 4\n" 210 "kernel_thread_starter:\n" 211 " la 2,0(10)\n" 212 " basr 14,9\n" 213 " la 2,0\n" 214 " br 11\n"); 215 216 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 217 { 218 struct pt_regs regs; 219 220 memset(®s, 0, sizeof(regs)); 221 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT; 222 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; 223 regs.gprs[9] = (unsigned long) fn; 224 regs.gprs[10] = (unsigned long) arg; 225 regs.gprs[11] = (unsigned long) do_exit; 226 regs.orig_gpr2 = -1; 227 228 /* Ok, create the new process.. */ 229 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 230 0, ®s, 0, NULL, NULL); 231 } 232 233 /* 234 * Free current thread data structures etc.. 235 */ 236 void exit_thread(void) 237 { 238 } 239 240 void flush_thread(void) 241 { 242 clear_used_math(); 243 clear_tsk_thread_flag(current, TIF_USEDFPU); 244 } 245 246 void release_thread(struct task_struct *dead_task) 247 { 248 } 249 250 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp, 251 unsigned long unused, 252 struct task_struct * p, struct pt_regs * regs) 253 { 254 struct fake_frame 255 { 256 struct stack_frame sf; 257 struct pt_regs childregs; 258 } *frame; 259 260 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 261 p->thread.ksp = (unsigned long) frame; 262 /* Store access registers to kernel stack of new process. */ 263 frame->childregs = *regs; 264 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 265 frame->childregs.gprs[15] = new_stackp; 266 frame->sf.back_chain = 0; 267 268 /* new return point is ret_from_fork */ 269 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 270 271 /* fake return stack for resume(), don't go back to schedule */ 272 frame->sf.gprs[9] = (unsigned long) frame; 273 274 /* Save access registers to new thread structure. */ 275 save_access_regs(&p->thread.acrs[0]); 276 277 #ifndef CONFIG_64BIT 278 /* 279 * save fprs to current->thread.fp_regs to merge them with 280 * the emulated registers and then copy the result to the child. 281 */ 282 save_fp_regs(¤t->thread.fp_regs); 283 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 284 sizeof(s390_fp_regs)); 285 /* Set a new TLS ? */ 286 if (clone_flags & CLONE_SETTLS) 287 p->thread.acrs[0] = regs->gprs[6]; 288 #else /* CONFIG_64BIT */ 289 /* Save the fpu registers to new thread structure. */ 290 save_fp_regs(&p->thread.fp_regs); 291 /* Set a new TLS ? */ 292 if (clone_flags & CLONE_SETTLS) { 293 if (test_thread_flag(TIF_31BIT)) { 294 p->thread.acrs[0] = (unsigned int) regs->gprs[6]; 295 } else { 296 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); 297 p->thread.acrs[1] = (unsigned int) regs->gprs[6]; 298 } 299 } 300 #endif /* CONFIG_64BIT */ 301 /* start new process with ar4 pointing to the correct address space */ 302 p->thread.mm_segment = get_fs(); 303 /* Don't copy debug registers */ 304 memset(&p->thread.per_info,0,sizeof(p->thread.per_info)); 305 306 return 0; 307 } 308 309 asmlinkage long sys_fork(void) 310 { 311 struct pt_regs *regs = task_pt_regs(current); 312 return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL); 313 } 314 315 asmlinkage long sys_clone(void) 316 { 317 struct pt_regs *regs = task_pt_regs(current); 318 unsigned long clone_flags; 319 unsigned long newsp; 320 int __user *parent_tidptr, *child_tidptr; 321 322 clone_flags = regs->gprs[3]; 323 newsp = regs->orig_gpr2; 324 parent_tidptr = (int __user *) regs->gprs[4]; 325 child_tidptr = (int __user *) regs->gprs[5]; 326 if (!newsp) 327 newsp = regs->gprs[15]; 328 return do_fork(clone_flags, newsp, regs, 0, 329 parent_tidptr, child_tidptr); 330 } 331 332 /* 333 * This is trivial, and on the face of it looks like it 334 * could equally well be done in user mode. 335 * 336 * Not so, for quite unobvious reasons - register pressure. 337 * In user mode vfork() cannot have a stack frame, and if 338 * done by calling the "clone()" system call directly, you 339 * do not have enough call-clobbered registers to hold all 340 * the information you need. 341 */ 342 asmlinkage long sys_vfork(void) 343 { 344 struct pt_regs *regs = task_pt_regs(current); 345 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 346 regs->gprs[15], regs, 0, NULL, NULL); 347 } 348 349 asmlinkage void execve_tail(void) 350 { 351 task_lock(current); 352 current->ptrace &= ~PT_DTRACE; 353 task_unlock(current); 354 current->thread.fp_regs.fpc = 0; 355 if (MACHINE_HAS_IEEE) 356 asm volatile("sfpc %0,%0" : : "d" (0)); 357 } 358 359 /* 360 * sys_execve() executes a new program. 361 */ 362 asmlinkage long sys_execve(void) 363 { 364 struct pt_regs *regs = task_pt_regs(current); 365 char *filename; 366 unsigned long result; 367 int rc; 368 369 filename = getname((char __user *) regs->orig_gpr2); 370 if (IS_ERR(filename)) { 371 result = PTR_ERR(filename); 372 goto out; 373 } 374 rc = do_execve(filename, (char __user * __user *) regs->gprs[3], 375 (char __user * __user *) regs->gprs[4], regs); 376 if (rc) { 377 result = rc; 378 goto out_putname; 379 } 380 execve_tail(); 381 result = regs->gprs[2]; 382 out_putname: 383 putname(filename); 384 out: 385 return result; 386 } 387 388 /* 389 * fill in the FPU structure for a core dump. 390 */ 391 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 392 { 393 #ifndef CONFIG_64BIT 394 /* 395 * save fprs to current->thread.fp_regs to merge them with 396 * the emulated registers and then copy the result to the dump. 397 */ 398 save_fp_regs(¤t->thread.fp_regs); 399 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 400 #else /* CONFIG_64BIT */ 401 save_fp_regs(fpregs); 402 #endif /* CONFIG_64BIT */ 403 return 1; 404 } 405 406 unsigned long get_wchan(struct task_struct *p) 407 { 408 struct stack_frame *sf, *low, *high; 409 unsigned long return_address; 410 int count; 411 412 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 413 return 0; 414 low = task_stack_page(p); 415 high = (struct stack_frame *) task_pt_regs(p); 416 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 417 if (sf <= low || sf > high) 418 return 0; 419 for (count = 0; count < 16; count++) { 420 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 421 if (sf <= low || sf > high) 422 return 0; 423 return_address = sf->gprs[8] & PSW_ADDR_INSN; 424 if (!in_sched_functions(return_address)) 425 return return_address; 426 } 427 return 0; 428 } 429 430