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/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> 40 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 49 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 50 51 /* 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. 58 */ 59 unsigned long thread_saved_pc(struct task_struct *tsk) 60 { 61 struct stack_frame *sf; 62 63 sf = (struct stack_frame *) tsk->thread.ksp; 64 sf = (struct stack_frame *) sf->back_chain; 65 return sf->gprs[8]; 66 } 67 68 /* 69 * Need to know about CPUs going idle? 70 */ 71 static struct notifier_block *idle_chain; 72 73 int register_idle_notifier(struct notifier_block *nb) 74 { 75 return notifier_chain_register(&idle_chain, nb); 76 } 77 EXPORT_SYMBOL(register_idle_notifier); 78 79 int unregister_idle_notifier(struct notifier_block *nb) 80 { 81 return notifier_chain_unregister(&idle_chain, nb); 82 } 83 EXPORT_SYMBOL(unregister_idle_notifier); 84 85 void do_monitor_call(struct pt_regs *regs, long interruption_code) 86 { 87 /* disable monitor call class 0 */ 88 __ctl_clear_bit(8, 15); 89 90 notifier_call_chain(&idle_chain, CPU_NOT_IDLE, 91 (void *)(long) smp_processor_id()); 92 } 93 94 extern void s390_handle_mcck(void); 95 /* 96 * The idle loop on a S390... 97 */ 98 void default_idle(void) 99 { 100 int cpu, rc; 101 102 /* CPU is going idle. */ 103 cpu = smp_processor_id(); 104 105 local_irq_disable(); 106 if (need_resched()) { 107 local_irq_enable(); 108 return; 109 } 110 111 rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu); 112 if (rc != NOTIFY_OK && rc != NOTIFY_DONE) 113 BUG(); 114 if (rc != NOTIFY_OK) { 115 local_irq_enable(); 116 return; 117 } 118 119 /* enable monitor call class 0 */ 120 __ctl_set_bit(8, 15); 121 122 #ifdef CONFIG_HOTPLUG_CPU 123 if (cpu_is_offline(cpu)) 124 cpu_die(); 125 #endif 126 127 local_mcck_disable(); 128 if (test_thread_flag(TIF_MCCK_PENDING)) { 129 local_mcck_enable(); 130 local_irq_enable(); 131 s390_handle_mcck(); 132 return; 133 } 134 135 /* Wait for external, I/O or machine check interrupt. */ 136 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_WAIT | 137 PSW_MASK_IO | PSW_MASK_EXT); 138 } 139 140 void cpu_idle(void) 141 { 142 for (;;) { 143 while (!need_resched()) 144 default_idle(); 145 146 preempt_enable_no_resched(); 147 schedule(); 148 preempt_disable(); 149 } 150 } 151 152 void show_regs(struct pt_regs *regs) 153 { 154 struct task_struct *tsk = current; 155 156 printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted()); 157 printk("Process %s (pid: %d, task: %p, ksp: %p)\n", 158 current->comm, current->pid, (void *) tsk, 159 (void *) tsk->thread.ksp); 160 161 show_registers(regs); 162 /* Show stack backtrace if pt_regs is from kernel mode */ 163 if (!(regs->psw.mask & PSW_MASK_PSTATE)) 164 show_trace(0,(unsigned long *) regs->gprs[15]); 165 } 166 167 extern void kernel_thread_starter(void); 168 169 __asm__(".align 4\n" 170 "kernel_thread_starter:\n" 171 " la 2,0(10)\n" 172 " basr 14,9\n" 173 " la 2,0\n" 174 " br 11\n"); 175 176 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 177 { 178 struct pt_regs regs; 179 180 memset(®s, 0, sizeof(regs)); 181 regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT; 182 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; 183 regs.gprs[9] = (unsigned long) fn; 184 regs.gprs[10] = (unsigned long) arg; 185 regs.gprs[11] = (unsigned long) do_exit; 186 regs.orig_gpr2 = -1; 187 188 /* Ok, create the new process.. */ 189 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 190 0, ®s, 0, NULL, NULL); 191 } 192 193 /* 194 * Free current thread data structures etc.. 195 */ 196 void exit_thread(void) 197 { 198 } 199 200 void flush_thread(void) 201 { 202 clear_used_math(); 203 clear_tsk_thread_flag(current, TIF_USEDFPU); 204 } 205 206 void release_thread(struct task_struct *dead_task) 207 { 208 } 209 210 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp, 211 unsigned long unused, 212 struct task_struct * p, struct pt_regs * regs) 213 { 214 struct fake_frame 215 { 216 struct stack_frame sf; 217 struct pt_regs childregs; 218 } *frame; 219 220 frame = ((struct fake_frame *) 221 (THREAD_SIZE + (unsigned long) p->thread_info)) - 1; 222 p->thread.ksp = (unsigned long) frame; 223 /* Store access registers to kernel stack of new process. */ 224 frame->childregs = *regs; 225 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 226 frame->childregs.gprs[15] = new_stackp; 227 frame->sf.back_chain = 0; 228 229 /* new return point is ret_from_fork */ 230 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 231 232 /* fake return stack for resume(), don't go back to schedule */ 233 frame->sf.gprs[9] = (unsigned long) frame; 234 235 /* Save access registers to new thread structure. */ 236 save_access_regs(&p->thread.acrs[0]); 237 238 #ifndef CONFIG_ARCH_S390X 239 /* 240 * save fprs to current->thread.fp_regs to merge them with 241 * the emulated registers and then copy the result to the child. 242 */ 243 save_fp_regs(¤t->thread.fp_regs); 244 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 245 sizeof(s390_fp_regs)); 246 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE; 247 /* Set a new TLS ? */ 248 if (clone_flags & CLONE_SETTLS) 249 p->thread.acrs[0] = regs->gprs[6]; 250 #else /* CONFIG_ARCH_S390X */ 251 /* Save the fpu registers to new thread structure. */ 252 save_fp_regs(&p->thread.fp_regs); 253 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE; 254 /* Set a new TLS ? */ 255 if (clone_flags & CLONE_SETTLS) { 256 if (test_thread_flag(TIF_31BIT)) { 257 p->thread.acrs[0] = (unsigned int) regs->gprs[6]; 258 } else { 259 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); 260 p->thread.acrs[1] = (unsigned int) regs->gprs[6]; 261 } 262 } 263 #endif /* CONFIG_ARCH_S390X */ 264 /* start new process with ar4 pointing to the correct address space */ 265 p->thread.mm_segment = get_fs(); 266 /* Don't copy debug registers */ 267 memset(&p->thread.per_info,0,sizeof(p->thread.per_info)); 268 269 return 0; 270 } 271 272 asmlinkage long sys_fork(struct pt_regs regs) 273 { 274 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL); 275 } 276 277 asmlinkage long sys_clone(struct pt_regs regs) 278 { 279 unsigned long clone_flags; 280 unsigned long newsp; 281 int __user *parent_tidptr, *child_tidptr; 282 283 clone_flags = regs.gprs[3]; 284 newsp = regs.orig_gpr2; 285 parent_tidptr = (int __user *) regs.gprs[4]; 286 child_tidptr = (int __user *) regs.gprs[5]; 287 if (!newsp) 288 newsp = regs.gprs[15]; 289 return do_fork(clone_flags, newsp, ®s, 0, 290 parent_tidptr, child_tidptr); 291 } 292 293 /* 294 * This is trivial, and on the face of it looks like it 295 * could equally well be done in user mode. 296 * 297 * Not so, for quite unobvious reasons - register pressure. 298 * In user mode vfork() cannot have a stack frame, and if 299 * done by calling the "clone()" system call directly, you 300 * do not have enough call-clobbered registers to hold all 301 * the information you need. 302 */ 303 asmlinkage long sys_vfork(struct pt_regs regs) 304 { 305 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 306 regs.gprs[15], ®s, 0, NULL, NULL); 307 } 308 309 /* 310 * sys_execve() executes a new program. 311 */ 312 asmlinkage long sys_execve(struct pt_regs regs) 313 { 314 int error; 315 char * filename; 316 317 filename = getname((char __user *) regs.orig_gpr2); 318 error = PTR_ERR(filename); 319 if (IS_ERR(filename)) 320 goto out; 321 error = do_execve(filename, (char __user * __user *) regs.gprs[3], 322 (char __user * __user *) regs.gprs[4], ®s); 323 if (error == 0) { 324 task_lock(current); 325 current->ptrace &= ~PT_DTRACE; 326 task_unlock(current); 327 current->thread.fp_regs.fpc = 0; 328 if (MACHINE_HAS_IEEE) 329 asm volatile("sfpc %0,%0" : : "d" (0)); 330 } 331 putname(filename); 332 out: 333 return error; 334 } 335 336 337 /* 338 * fill in the FPU structure for a core dump. 339 */ 340 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 341 { 342 #ifndef CONFIG_ARCH_S390X 343 /* 344 * save fprs to current->thread.fp_regs to merge them with 345 * the emulated registers and then copy the result to the dump. 346 */ 347 save_fp_regs(¤t->thread.fp_regs); 348 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 349 #else /* CONFIG_ARCH_S390X */ 350 save_fp_regs(fpregs); 351 #endif /* CONFIG_ARCH_S390X */ 352 return 1; 353 } 354 355 /* 356 * fill in the user structure for a core dump.. 357 */ 358 void dump_thread(struct pt_regs * regs, struct user * dump) 359 { 360 361 /* changed the size calculations - should hopefully work better. lbt */ 362 dump->magic = CMAGIC; 363 dump->start_code = 0; 364 dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1); 365 dump->u_tsize = current->mm->end_code >> PAGE_SHIFT; 366 dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT; 367 dump->u_dsize -= dump->u_tsize; 368 dump->u_ssize = 0; 369 if (dump->start_stack < TASK_SIZE) 370 dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT; 371 memcpy(&dump->regs, regs, sizeof(s390_regs)); 372 dump_fpu (regs, &dump->regs.fp_regs); 373 dump->regs.per_info = current->thread.per_info; 374 } 375 376 unsigned long get_wchan(struct task_struct *p) 377 { 378 struct stack_frame *sf, *low, *high; 379 unsigned long return_address; 380 int count; 381 382 if (!p || p == current || p->state == TASK_RUNNING || !p->thread_info) 383 return 0; 384 low = (struct stack_frame *) p->thread_info; 385 high = (struct stack_frame *) 386 ((unsigned long) p->thread_info + THREAD_SIZE) - 1; 387 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 388 if (sf <= low || sf > high) 389 return 0; 390 for (count = 0; count < 16; count++) { 391 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 392 if (sf <= low || sf > high) 393 return 0; 394 return_address = sf->gprs[8] & PSW_ADDR_INSN; 395 if (!in_sched_functions(return_address)) 396 return return_address; 397 } 398 return 0; 399 } 400 401