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 <linux/tick.h> 40 #include <linux/elfcore.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> 48 #include <asm/cpu.h> 49 #include "entry.h" 50 51 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 52 53 /* 54 * Return saved PC of a blocked thread. used in kernel/sched. 55 * resume in entry.S does not create a new stack frame, it 56 * just stores the registers %r6-%r15 to the frame given by 57 * schedule. We want to return the address of the caller of 58 * schedule, so we have to walk the backchain one time to 59 * find the frame schedule() store its return address. 60 */ 61 unsigned long thread_saved_pc(struct task_struct *tsk) 62 { 63 struct stack_frame *sf, *low, *high; 64 65 if (!tsk || !task_stack_page(tsk)) 66 return 0; 67 low = task_stack_page(tsk); 68 high = (struct stack_frame *) task_pt_regs(tsk); 69 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN); 70 if (sf <= low || sf > high) 71 return 0; 72 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 73 if (sf <= low || sf > high) 74 return 0; 75 return sf->gprs[8]; 76 } 77 78 /* 79 * Need to know about CPUs going idle? 80 */ 81 static ATOMIC_NOTIFIER_HEAD(idle_chain); 82 DEFINE_PER_CPU(struct s390_idle_data, s390_idle); 83 84 int register_idle_notifier(struct notifier_block *nb) 85 { 86 return atomic_notifier_chain_register(&idle_chain, nb); 87 } 88 EXPORT_SYMBOL(register_idle_notifier); 89 90 int unregister_idle_notifier(struct notifier_block *nb) 91 { 92 return atomic_notifier_chain_unregister(&idle_chain, nb); 93 } 94 EXPORT_SYMBOL(unregister_idle_notifier); 95 96 static int s390_idle_enter(void) 97 { 98 struct s390_idle_data *idle; 99 int nr_calls = 0; 100 void *hcpu; 101 int rc; 102 103 hcpu = (void *)(long)smp_processor_id(); 104 rc = __atomic_notifier_call_chain(&idle_chain, S390_CPU_IDLE, hcpu, -1, 105 &nr_calls); 106 if (rc == NOTIFY_BAD) { 107 nr_calls--; 108 __atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE, 109 hcpu, nr_calls, NULL); 110 return rc; 111 } 112 idle = &__get_cpu_var(s390_idle); 113 spin_lock(&idle->lock); 114 idle->idle_count++; 115 idle->in_idle = 1; 116 idle->idle_enter = get_clock(); 117 spin_unlock(&idle->lock); 118 return NOTIFY_OK; 119 } 120 121 void s390_idle_leave(void) 122 { 123 struct s390_idle_data *idle; 124 125 idle = &__get_cpu_var(s390_idle); 126 spin_lock(&idle->lock); 127 idle->idle_time += get_clock() - idle->idle_enter; 128 idle->in_idle = 0; 129 spin_unlock(&idle->lock); 130 atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE, 131 (void *)(long) smp_processor_id()); 132 } 133 134 extern void s390_handle_mcck(void); 135 /* 136 * The idle loop on a S390... 137 */ 138 static void default_idle(void) 139 { 140 /* CPU is going idle. */ 141 local_irq_disable(); 142 if (need_resched()) { 143 local_irq_enable(); 144 return; 145 } 146 if (s390_idle_enter() == NOTIFY_BAD) { 147 local_irq_enable(); 148 return; 149 } 150 #ifdef CONFIG_HOTPLUG_CPU 151 if (cpu_is_offline(smp_processor_id())) { 152 preempt_enable_no_resched(); 153 cpu_die(); 154 } 155 #endif 156 local_mcck_disable(); 157 if (test_thread_flag(TIF_MCCK_PENDING)) { 158 local_mcck_enable(); 159 s390_idle_leave(); 160 local_irq_enable(); 161 s390_handle_mcck(); 162 return; 163 } 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 tick_nohz_stop_sched_tick(); 174 while (!need_resched()) 175 default_idle(); 176 tick_nohz_restart_sched_tick(); 177 preempt_enable_no_resched(); 178 schedule(); 179 preempt_disable(); 180 } 181 } 182 183 void show_regs(struct pt_regs *regs) 184 { 185 print_modules(); 186 printk("CPU: %d %s %s %.*s\n", 187 task_thread_info(current)->cpu, print_tainted(), 188 init_utsname()->release, 189 (int)strcspn(init_utsname()->version, " "), 190 init_utsname()->version); 191 printk("Process %s (pid: %d, task: %p, ksp: %p)\n", 192 current->comm, current->pid, current, 193 (void *) current->thread.ksp); 194 show_registers(regs); 195 /* Show stack backtrace if pt_regs is from kernel mode */ 196 if (!(regs->psw.mask & PSW_MASK_PSTATE)) 197 show_trace(NULL, (unsigned long *) regs->gprs[15]); 198 show_last_breaking_event(regs); 199 } 200 201 extern void kernel_thread_starter(void); 202 203 asm( 204 ".align 4\n" 205 "kernel_thread_starter:\n" 206 " la 2,0(10)\n" 207 " basr 14,9\n" 208 " la 2,0\n" 209 " br 11\n"); 210 211 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 212 { 213 struct pt_regs regs; 214 215 memset(®s, 0, sizeof(regs)); 216 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT; 217 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; 218 regs.gprs[9] = (unsigned long) fn; 219 regs.gprs[10] = (unsigned long) arg; 220 regs.gprs[11] = (unsigned long) do_exit; 221 regs.orig_gpr2 = -1; 222 223 /* Ok, create the new process.. */ 224 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 225 0, ®s, 0, NULL, NULL); 226 } 227 228 /* 229 * Free current thread data structures etc.. 230 */ 231 void exit_thread(void) 232 { 233 } 234 235 void flush_thread(void) 236 { 237 clear_used_math(); 238 clear_tsk_thread_flag(current, TIF_USEDFPU); 239 } 240 241 void release_thread(struct task_struct *dead_task) 242 { 243 } 244 245 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp, 246 unsigned long unused, 247 struct task_struct * p, struct pt_regs * regs) 248 { 249 struct fake_frame 250 { 251 struct stack_frame sf; 252 struct pt_regs childregs; 253 } *frame; 254 255 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 256 p->thread.ksp = (unsigned long) frame; 257 /* Store access registers to kernel stack of new process. */ 258 frame->childregs = *regs; 259 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 260 frame->childregs.gprs[15] = new_stackp; 261 frame->sf.back_chain = 0; 262 263 /* new return point is ret_from_fork */ 264 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 265 266 /* fake return stack for resume(), don't go back to schedule */ 267 frame->sf.gprs[9] = (unsigned long) frame; 268 269 /* Save access registers to new thread structure. */ 270 save_access_regs(&p->thread.acrs[0]); 271 272 #ifndef CONFIG_64BIT 273 /* 274 * save fprs to current->thread.fp_regs to merge them with 275 * the emulated registers and then copy the result to the child. 276 */ 277 save_fp_regs(¤t->thread.fp_regs); 278 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 279 sizeof(s390_fp_regs)); 280 /* Set a new TLS ? */ 281 if (clone_flags & CLONE_SETTLS) 282 p->thread.acrs[0] = regs->gprs[6]; 283 #else /* CONFIG_64BIT */ 284 /* Save the fpu registers to new thread structure. */ 285 save_fp_regs(&p->thread.fp_regs); 286 /* Set a new TLS ? */ 287 if (clone_flags & CLONE_SETTLS) { 288 if (test_thread_flag(TIF_31BIT)) { 289 p->thread.acrs[0] = (unsigned int) regs->gprs[6]; 290 } else { 291 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); 292 p->thread.acrs[1] = (unsigned int) regs->gprs[6]; 293 } 294 } 295 #endif /* CONFIG_64BIT */ 296 /* start new process with ar4 pointing to the correct address space */ 297 p->thread.mm_segment = get_fs(); 298 /* Don't copy debug registers */ 299 memset(&p->thread.per_info,0,sizeof(p->thread.per_info)); 300 301 return 0; 302 } 303 304 asmlinkage long sys_fork(void) 305 { 306 struct pt_regs *regs = task_pt_regs(current); 307 return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL); 308 } 309 310 asmlinkage long sys_clone(void) 311 { 312 struct pt_regs *regs = task_pt_regs(current); 313 unsigned long clone_flags; 314 unsigned long newsp; 315 int __user *parent_tidptr, *child_tidptr; 316 317 clone_flags = regs->gprs[3]; 318 newsp = regs->orig_gpr2; 319 parent_tidptr = (int __user *) regs->gprs[4]; 320 child_tidptr = (int __user *) regs->gprs[5]; 321 if (!newsp) 322 newsp = regs->gprs[15]; 323 return do_fork(clone_flags, newsp, regs, 0, 324 parent_tidptr, child_tidptr); 325 } 326 327 /* 328 * This is trivial, and on the face of it looks like it 329 * could equally well be done in user mode. 330 * 331 * Not so, for quite unobvious reasons - register pressure. 332 * In user mode vfork() cannot have a stack frame, and if 333 * done by calling the "clone()" system call directly, you 334 * do not have enough call-clobbered registers to hold all 335 * the information you need. 336 */ 337 asmlinkage long sys_vfork(void) 338 { 339 struct pt_regs *regs = task_pt_regs(current); 340 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 341 regs->gprs[15], regs, 0, NULL, NULL); 342 } 343 344 asmlinkage void execve_tail(void) 345 { 346 task_lock(current); 347 current->ptrace &= ~PT_DTRACE; 348 task_unlock(current); 349 current->thread.fp_regs.fpc = 0; 350 if (MACHINE_HAS_IEEE) 351 asm volatile("sfpc %0,%0" : : "d" (0)); 352 } 353 354 /* 355 * sys_execve() executes a new program. 356 */ 357 asmlinkage long sys_execve(void) 358 { 359 struct pt_regs *regs = task_pt_regs(current); 360 char *filename; 361 unsigned long result; 362 int rc; 363 364 filename = getname((char __user *) regs->orig_gpr2); 365 if (IS_ERR(filename)) { 366 result = PTR_ERR(filename); 367 goto out; 368 } 369 rc = do_execve(filename, (char __user * __user *) regs->gprs[3], 370 (char __user * __user *) regs->gprs[4], regs); 371 if (rc) { 372 result = rc; 373 goto out_putname; 374 } 375 execve_tail(); 376 result = regs->gprs[2]; 377 out_putname: 378 putname(filename); 379 out: 380 return result; 381 } 382 383 /* 384 * fill in the FPU structure for a core dump. 385 */ 386 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 387 { 388 #ifndef CONFIG_64BIT 389 /* 390 * save fprs to current->thread.fp_regs to merge them with 391 * the emulated registers and then copy the result to the dump. 392 */ 393 save_fp_regs(¤t->thread.fp_regs); 394 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 395 #else /* CONFIG_64BIT */ 396 save_fp_regs(fpregs); 397 #endif /* CONFIG_64BIT */ 398 return 1; 399 } 400 401 unsigned long get_wchan(struct task_struct *p) 402 { 403 struct stack_frame *sf, *low, *high; 404 unsigned long return_address; 405 int count; 406 407 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 408 return 0; 409 low = task_stack_page(p); 410 high = (struct stack_frame *) task_pt_regs(p); 411 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 412 if (sf <= low || sf > high) 413 return 0; 414 for (count = 0; count < 16; count++) { 415 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 416 if (sf <= low || sf > high) 417 return 0; 418 return_address = sf->gprs[8] & PSW_ADDR_INSN; 419 if (!in_sched_functions(return_address)) 420 return return_address; 421 } 422 return 0; 423 } 424 425