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 /* 95 * The idle loop on a S390... 96 */ 97 void default_idle(void) 98 { 99 psw_t wait_psw; 100 unsigned long reg; 101 int cpu, rc; 102 103 local_irq_disable(); 104 if (need_resched()) { 105 local_irq_enable(); 106 schedule(); 107 return; 108 } 109 110 /* 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; 118 } 119 120 /* enable monitor call class 0 */ 121 __ctl_set_bit(8, 15); 122 123 #ifdef CONFIG_HOTPLUG_CPU 124 if (cpu_is_offline(smp_processor_id())) 125 cpu_die(); 126 #endif 127 128 /* 129 * Wait for external, I/O or machine check interrupt and 130 * switch off machine check bit after the wait has ended. 131 */ 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 */ 160 } 161 162 void cpu_idle(void) 163 { 164 for (;;) 165 default_idle(); 166 } 167 168 void show_regs(struct pt_regs *regs) 169 { 170 struct task_struct *tsk = current; 171 172 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); 176 177 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]); 181 } 182 183 extern void kernel_thread_starter(void); 184 185 __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"); 191 192 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 193 { 194 struct pt_regs regs; 195 196 memset(®s, 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; 203 204 /* Ok, create the new process.. */ 205 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 206 0, ®s, 0, NULL, NULL); 207 } 208 209 /* 210 * Free current thread data structures etc.. 211 */ 212 void exit_thread(void) 213 { 214 } 215 216 void flush_thread(void) 217 { 218 clear_used_math(); 219 clear_tsk_thread_flag(current, TIF_USEDFPU); 220 } 221 222 void release_thread(struct task_struct *dead_task) 223 { 224 } 225 226 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) 229 { 230 struct fake_frame 231 { 232 struct stack_frame sf; 233 struct pt_regs childregs; 234 } *frame; 235 236 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; 244 245 /* new return point is ret_from_fork */ 246 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 247 248 /* fake return stack for resume(), don't go back to schedule */ 249 frame->sf.gprs[9] = (unsigned long) frame; 250 251 /* Save access registers to new thread structure. */ 252 save_access_regs(&p->thread.acrs[0]); 253 254 #ifndef CONFIG_ARCH_S390X 255 /* 256 * save fprs to current->thread.fp_regs to merge them with 257 * the emulated registers and then copy the result to the child. 258 */ 259 save_fp_regs(¤t->thread.fp_regs); 260 memcpy(&p->thread.fp_regs, ¤t->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]; 277 } 278 } 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)); 284 285 return 0; 286 } 287 288 asmlinkage long sys_fork(struct pt_regs regs) 289 { 290 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL); 291 } 292 293 asmlinkage long sys_clone(struct pt_regs regs) 294 { 295 unsigned long clone_flags; 296 unsigned long newsp; 297 int __user *parent_tidptr, *child_tidptr; 298 299 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, ®s, 0, 306 parent_tidptr, child_tidptr); 307 } 308 309 /* 310 * This is trivial, and on the face of it looks like it 311 * could equally well be done in user mode. 312 * 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. 318 */ 319 asmlinkage long sys_vfork(struct pt_regs regs) 320 { 321 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 322 regs.gprs[15], ®s, 0, NULL, NULL); 323 } 324 325 /* 326 * sys_execve() executes a new program. 327 */ 328 asmlinkage long sys_execve(struct pt_regs regs) 329 { 330 int error; 331 char * filename; 332 333 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], ®s); 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)); 346 } 347 putname(filename); 348 out: 349 return error; 350 } 351 352 353 /* 354 * fill in the FPU structure for a core dump. 355 */ 356 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 357 { 358 #ifndef CONFIG_ARCH_S390X 359 /* 360 * save fprs to current->thread.fp_regs to merge them with 361 * the emulated registers and then copy the result to the dump. 362 */ 363 save_fp_regs(¤t->thread.fp_regs); 364 memcpy(fpregs, ¤t->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; 369 } 370 371 /* 372 * fill in the user structure for a core dump.. 373 */ 374 void dump_thread(struct pt_regs * regs, struct user * dump) 375 { 376 377 /* 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; 390 } 391 392 unsigned long get_wchan(struct task_struct *p) 393 { 394 struct stack_frame *sf, *low, *high; 395 unsigned long return_address; 396 int count; 397 398 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; 413 } 414 return 0; 415 } 416 417