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 #ifdef CONFIG_SMP 118 struct s390_idle_data *idle; 119 #endif 120 121 /* CPU is going idle. */ 122 cpu = smp_processor_id(); 123 124 local_irq_disable(); 125 if (need_resched()) { 126 local_irq_enable(); 127 return; 128 } 129 130 rc = atomic_notifier_call_chain(&idle_chain, 131 S390_CPU_IDLE, (void *)(long) cpu); 132 if (rc != NOTIFY_OK && rc != NOTIFY_DONE) 133 BUG(); 134 if (rc != NOTIFY_OK) { 135 local_irq_enable(); 136 return; 137 } 138 139 /* enable monitor call class 0 */ 140 __ctl_set_bit(8, 15); 141 142 #ifdef CONFIG_HOTPLUG_CPU 143 if (cpu_is_offline(cpu)) { 144 preempt_enable_no_resched(); 145 cpu_die(); 146 } 147 #endif 148 149 local_mcck_disable(); 150 if (test_thread_flag(TIF_MCCK_PENDING)) { 151 local_mcck_enable(); 152 local_irq_enable(); 153 s390_handle_mcck(); 154 return; 155 } 156 #ifdef CONFIG_SMP 157 idle = &__get_cpu_var(s390_idle); 158 spin_lock(&idle->lock); 159 idle->idle_count++; 160 idle->in_idle = 1; 161 idle->idle_enter = get_clock(); 162 spin_unlock(&idle->lock); 163 #endif 164 trace_hardirqs_on(); 165 /* Wait for external, I/O or machine check interrupt. */ 166 __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT | 167 PSW_MASK_IO | PSW_MASK_EXT); 168 } 169 170 void cpu_idle(void) 171 { 172 for (;;) { 173 while (!need_resched()) 174 default_idle(); 175 176 preempt_enable_no_resched(); 177 schedule(); 178 preempt_disable(); 179 } 180 } 181 182 void show_regs(struct pt_regs *regs) 183 { 184 print_modules(); 185 printk("CPU: %d %s %s %.*s\n", 186 task_thread_info(current)->cpu, print_tainted(), 187 init_utsname()->release, 188 (int)strcspn(init_utsname()->version, " "), 189 init_utsname()->version); 190 printk("Process %s (pid: %d, task: %p, ksp: %p)\n", 191 current->comm, current->pid, current, 192 (void *) current->thread.ksp); 193 show_registers(regs); 194 /* Show stack backtrace if pt_regs is from kernel mode */ 195 if (!(regs->psw.mask & PSW_MASK_PSTATE)) 196 show_trace(NULL, (unsigned long *) regs->gprs[15]); 197 } 198 199 extern void kernel_thread_starter(void); 200 201 asm( 202 ".align 4\n" 203 "kernel_thread_starter:\n" 204 " la 2,0(10)\n" 205 " basr 14,9\n" 206 " la 2,0\n" 207 " br 11\n"); 208 209 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 210 { 211 struct pt_regs regs; 212 213 memset(®s, 0, sizeof(regs)); 214 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT; 215 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; 216 regs.gprs[9] = (unsigned long) fn; 217 regs.gprs[10] = (unsigned long) arg; 218 regs.gprs[11] = (unsigned long) do_exit; 219 regs.orig_gpr2 = -1; 220 221 /* Ok, create the new process.. */ 222 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 223 0, ®s, 0, NULL, NULL); 224 } 225 226 /* 227 * Free current thread data structures etc.. 228 */ 229 void exit_thread(void) 230 { 231 } 232 233 void flush_thread(void) 234 { 235 clear_used_math(); 236 clear_tsk_thread_flag(current, TIF_USEDFPU); 237 } 238 239 void release_thread(struct task_struct *dead_task) 240 { 241 } 242 243 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp, 244 unsigned long unused, 245 struct task_struct * p, struct pt_regs * regs) 246 { 247 struct fake_frame 248 { 249 struct stack_frame sf; 250 struct pt_regs childregs; 251 } *frame; 252 253 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 254 p->thread.ksp = (unsigned long) frame; 255 /* Store access registers to kernel stack of new process. */ 256 frame->childregs = *regs; 257 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 258 frame->childregs.gprs[15] = new_stackp; 259 frame->sf.back_chain = 0; 260 261 /* new return point is ret_from_fork */ 262 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 263 264 /* fake return stack for resume(), don't go back to schedule */ 265 frame->sf.gprs[9] = (unsigned long) frame; 266 267 /* Save access registers to new thread structure. */ 268 save_access_regs(&p->thread.acrs[0]); 269 270 #ifndef CONFIG_64BIT 271 /* 272 * save fprs to current->thread.fp_regs to merge them with 273 * the emulated registers and then copy the result to the child. 274 */ 275 save_fp_regs(¤t->thread.fp_regs); 276 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 277 sizeof(s390_fp_regs)); 278 /* Set a new TLS ? */ 279 if (clone_flags & CLONE_SETTLS) 280 p->thread.acrs[0] = regs->gprs[6]; 281 #else /* CONFIG_64BIT */ 282 /* Save the fpu registers to new thread structure. */ 283 save_fp_regs(&p->thread.fp_regs); 284 /* Set a new TLS ? */ 285 if (clone_flags & CLONE_SETTLS) { 286 if (test_thread_flag(TIF_31BIT)) { 287 p->thread.acrs[0] = (unsigned int) regs->gprs[6]; 288 } else { 289 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); 290 p->thread.acrs[1] = (unsigned int) regs->gprs[6]; 291 } 292 } 293 #endif /* CONFIG_64BIT */ 294 /* start new process with ar4 pointing to the correct address space */ 295 p->thread.mm_segment = get_fs(); 296 /* Don't copy debug registers */ 297 memset(&p->thread.per_info,0,sizeof(p->thread.per_info)); 298 299 return 0; 300 } 301 302 asmlinkage long sys_fork(void) 303 { 304 struct pt_regs *regs = task_pt_regs(current); 305 return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL); 306 } 307 308 asmlinkage long sys_clone(void) 309 { 310 struct pt_regs *regs = task_pt_regs(current); 311 unsigned long clone_flags; 312 unsigned long newsp; 313 int __user *parent_tidptr, *child_tidptr; 314 315 clone_flags = regs->gprs[3]; 316 newsp = regs->orig_gpr2; 317 parent_tidptr = (int __user *) regs->gprs[4]; 318 child_tidptr = (int __user *) regs->gprs[5]; 319 if (!newsp) 320 newsp = regs->gprs[15]; 321 return do_fork(clone_flags, newsp, regs, 0, 322 parent_tidptr, child_tidptr); 323 } 324 325 /* 326 * This is trivial, and on the face of it looks like it 327 * could equally well be done in user mode. 328 * 329 * Not so, for quite unobvious reasons - register pressure. 330 * In user mode vfork() cannot have a stack frame, and if 331 * done by calling the "clone()" system call directly, you 332 * do not have enough call-clobbered registers to hold all 333 * the information you need. 334 */ 335 asmlinkage long sys_vfork(void) 336 { 337 struct pt_regs *regs = task_pt_regs(current); 338 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 339 regs->gprs[15], regs, 0, NULL, NULL); 340 } 341 342 asmlinkage void execve_tail(void) 343 { 344 task_lock(current); 345 current->ptrace &= ~PT_DTRACE; 346 task_unlock(current); 347 current->thread.fp_regs.fpc = 0; 348 if (MACHINE_HAS_IEEE) 349 asm volatile("sfpc %0,%0" : : "d" (0)); 350 } 351 352 /* 353 * sys_execve() executes a new program. 354 */ 355 asmlinkage long sys_execve(void) 356 { 357 struct pt_regs *regs = task_pt_regs(current); 358 char *filename; 359 unsigned long result; 360 int rc; 361 362 filename = getname((char __user *) regs->orig_gpr2); 363 if (IS_ERR(filename)) { 364 result = PTR_ERR(filename); 365 goto out; 366 } 367 rc = do_execve(filename, (char __user * __user *) regs->gprs[3], 368 (char __user * __user *) regs->gprs[4], regs); 369 if (rc) { 370 result = rc; 371 goto out_putname; 372 } 373 execve_tail(); 374 result = regs->gprs[2]; 375 out_putname: 376 putname(filename); 377 out: 378 return result; 379 } 380 381 /* 382 * fill in the FPU structure for a core dump. 383 */ 384 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 385 { 386 #ifndef CONFIG_64BIT 387 /* 388 * save fprs to current->thread.fp_regs to merge them with 389 * the emulated registers and then copy the result to the dump. 390 */ 391 save_fp_regs(¤t->thread.fp_regs); 392 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 393 #else /* CONFIG_64BIT */ 394 save_fp_regs(fpregs); 395 #endif /* CONFIG_64BIT */ 396 return 1; 397 } 398 399 unsigned long get_wchan(struct task_struct *p) 400 { 401 struct stack_frame *sf, *low, *high; 402 unsigned long return_address; 403 int count; 404 405 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 406 return 0; 407 low = task_stack_page(p); 408 high = (struct stack_frame *) task_pt_regs(p); 409 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 410 if (sf <= low || sf > high) 411 return 0; 412 for (count = 0; count < 16; count++) { 413 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 414 if (sf <= low || sf > high) 415 return 0; 416 return_address = sf->gprs[8] & PSW_ADDR_INSN; 417 if (!in_sched_functions(return_address)) 418 return return_address; 419 } 420 return 0; 421 } 422 423