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/smp.h> 25 #include <linux/smp_lock.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/a.out.h> 33 #include <linux/interrupt.h> 34 #include <linux/delay.h> 35 #include <linux/reboot.h> 36 #include <linux/init.h> 37 #include <linux/module.h> 38 #include <linux/notifier.h> 39 40 #include <asm/uaccess.h> 41 #include <asm/pgtable.h> 42 #include <asm/system.h> 43 #include <asm/io.h> 44 #include <asm/processor.h> 45 #include <asm/irq.h> 46 #include <asm/timer.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 /* disable monitor call class 0 */ 95 __ctl_clear_bit(8, 15); 96 97 atomic_notifier_call_chain(&idle_chain, CPU_NOT_IDLE, 98 (void *)(long) smp_processor_id()); 99 } 100 101 extern void s390_handle_mcck(void); 102 /* 103 * The idle loop on a S390... 104 */ 105 static void default_idle(void) 106 { 107 int cpu, rc; 108 109 /* CPU is going idle. */ 110 cpu = smp_processor_id(); 111 112 local_irq_disable(); 113 if (need_resched()) { 114 local_irq_enable(); 115 return; 116 } 117 118 rc = atomic_notifier_call_chain(&idle_chain, 119 CPU_IDLE, (void *)(long) cpu); 120 if (rc != NOTIFY_OK && rc != NOTIFY_DONE) 121 BUG(); 122 if (rc != NOTIFY_OK) { 123 local_irq_enable(); 124 return; 125 } 126 127 /* enable monitor call class 0 */ 128 __ctl_set_bit(8, 15); 129 130 #ifdef CONFIG_HOTPLUG_CPU 131 if (cpu_is_offline(cpu)) { 132 preempt_enable_no_resched(); 133 cpu_die(); 134 } 135 #endif 136 137 local_mcck_disable(); 138 if (test_thread_flag(TIF_MCCK_PENDING)) { 139 local_mcck_enable(); 140 local_irq_enable(); 141 s390_handle_mcck(); 142 return; 143 } 144 145 trace_hardirqs_on(); 146 /* Wait for external, I/O or machine check interrupt. */ 147 __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT | 148 PSW_MASK_IO | PSW_MASK_EXT); 149 } 150 151 void cpu_idle(void) 152 { 153 for (;;) { 154 while (!need_resched()) 155 default_idle(); 156 157 preempt_enable_no_resched(); 158 schedule(); 159 preempt_disable(); 160 } 161 } 162 163 void show_regs(struct pt_regs *regs) 164 { 165 struct task_struct *tsk = current; 166 167 printk("CPU: %d %s\n", task_thread_info(tsk)->cpu, print_tainted()); 168 printk("Process %s (pid: %d, task: %p, ksp: %p)\n", 169 current->comm, current->pid, (void *) tsk, 170 (void *) tsk->thread.ksp); 171 172 show_registers(regs); 173 /* Show stack backtrace if pt_regs is from kernel mode */ 174 if (!(regs->psw.mask & PSW_MASK_PSTATE)) 175 show_trace(NULL, (unsigned long *) regs->gprs[15]); 176 } 177 178 extern void kernel_thread_starter(void); 179 180 asm( 181 ".align 4\n" 182 "kernel_thread_starter:\n" 183 " la 2,0(10)\n" 184 " basr 14,9\n" 185 " la 2,0\n" 186 " br 11\n"); 187 188 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 189 { 190 struct pt_regs regs; 191 192 memset(®s, 0, sizeof(regs)); 193 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT; 194 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; 195 regs.gprs[9] = (unsigned long) fn; 196 regs.gprs[10] = (unsigned long) arg; 197 regs.gprs[11] = (unsigned long) do_exit; 198 regs.orig_gpr2 = -1; 199 200 /* Ok, create the new process.. */ 201 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 202 0, ®s, 0, NULL, NULL); 203 } 204 205 /* 206 * Free current thread data structures etc.. 207 */ 208 void exit_thread(void) 209 { 210 } 211 212 void flush_thread(void) 213 { 214 clear_used_math(); 215 clear_tsk_thread_flag(current, TIF_USEDFPU); 216 } 217 218 void release_thread(struct task_struct *dead_task) 219 { 220 } 221 222 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp, 223 unsigned long unused, 224 struct task_struct * p, struct pt_regs * regs) 225 { 226 struct fake_frame 227 { 228 struct stack_frame sf; 229 struct pt_regs childregs; 230 } *frame; 231 232 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 233 p->thread.ksp = (unsigned long) frame; 234 /* Store access registers to kernel stack of new process. */ 235 frame->childregs = *regs; 236 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 237 frame->childregs.gprs[15] = new_stackp; 238 frame->sf.back_chain = 0; 239 240 /* new return point is ret_from_fork */ 241 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 242 243 /* fake return stack for resume(), don't go back to schedule */ 244 frame->sf.gprs[9] = (unsigned long) frame; 245 246 /* Save access registers to new thread structure. */ 247 save_access_regs(&p->thread.acrs[0]); 248 249 #ifndef CONFIG_64BIT 250 /* 251 * save fprs to current->thread.fp_regs to merge them with 252 * the emulated registers and then copy the result to the child. 253 */ 254 save_fp_regs(¤t->thread.fp_regs); 255 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 256 sizeof(s390_fp_regs)); 257 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE; 258 /* Set a new TLS ? */ 259 if (clone_flags & CLONE_SETTLS) 260 p->thread.acrs[0] = regs->gprs[6]; 261 #else /* CONFIG_64BIT */ 262 /* Save the fpu registers to new thread structure. */ 263 save_fp_regs(&p->thread.fp_regs); 264 p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE; 265 /* Set a new TLS ? */ 266 if (clone_flags & CLONE_SETTLS) { 267 if (test_thread_flag(TIF_31BIT)) { 268 p->thread.acrs[0] = (unsigned int) regs->gprs[6]; 269 } else { 270 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); 271 p->thread.acrs[1] = (unsigned int) regs->gprs[6]; 272 } 273 } 274 #endif /* CONFIG_64BIT */ 275 /* start new process with ar4 pointing to the correct address space */ 276 p->thread.mm_segment = get_fs(); 277 /* Don't copy debug registers */ 278 memset(&p->thread.per_info,0,sizeof(p->thread.per_info)); 279 280 return 0; 281 } 282 283 asmlinkage long sys_fork(struct pt_regs regs) 284 { 285 return do_fork(SIGCHLD, regs.gprs[15], ®s, 0, NULL, NULL); 286 } 287 288 asmlinkage long sys_clone(struct pt_regs regs) 289 { 290 unsigned long clone_flags; 291 unsigned long newsp; 292 int __user *parent_tidptr, *child_tidptr; 293 294 clone_flags = regs.gprs[3]; 295 newsp = regs.orig_gpr2; 296 parent_tidptr = (int __user *) regs.gprs[4]; 297 child_tidptr = (int __user *) regs.gprs[5]; 298 if (!newsp) 299 newsp = regs.gprs[15]; 300 return do_fork(clone_flags, newsp, ®s, 0, 301 parent_tidptr, child_tidptr); 302 } 303 304 /* 305 * This is trivial, and on the face of it looks like it 306 * could equally well be done in user mode. 307 * 308 * Not so, for quite unobvious reasons - register pressure. 309 * In user mode vfork() cannot have a stack frame, and if 310 * done by calling the "clone()" system call directly, you 311 * do not have enough call-clobbered registers to hold all 312 * the information you need. 313 */ 314 asmlinkage long sys_vfork(struct pt_regs regs) 315 { 316 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 317 regs.gprs[15], ®s, 0, NULL, NULL); 318 } 319 320 /* 321 * sys_execve() executes a new program. 322 */ 323 asmlinkage long sys_execve(struct pt_regs regs) 324 { 325 int error; 326 char * filename; 327 328 filename = getname((char __user *) regs.orig_gpr2); 329 error = PTR_ERR(filename); 330 if (IS_ERR(filename)) 331 goto out; 332 error = do_execve(filename, (char __user * __user *) regs.gprs[3], 333 (char __user * __user *) regs.gprs[4], ®s); 334 if (error == 0) { 335 task_lock(current); 336 current->ptrace &= ~PT_DTRACE; 337 task_unlock(current); 338 current->thread.fp_regs.fpc = 0; 339 if (MACHINE_HAS_IEEE) 340 asm volatile("sfpc %0,%0" : : "d" (0)); 341 } 342 putname(filename); 343 out: 344 return error; 345 } 346 347 348 /* 349 * fill in the FPU structure for a core dump. 350 */ 351 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 352 { 353 #ifndef CONFIG_64BIT 354 /* 355 * save fprs to current->thread.fp_regs to merge them with 356 * the emulated registers and then copy the result to the dump. 357 */ 358 save_fp_regs(¤t->thread.fp_regs); 359 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 360 #else /* CONFIG_64BIT */ 361 save_fp_regs(fpregs); 362 #endif /* CONFIG_64BIT */ 363 return 1; 364 } 365 366 unsigned long get_wchan(struct task_struct *p) 367 { 368 struct stack_frame *sf, *low, *high; 369 unsigned long return_address; 370 int count; 371 372 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 373 return 0; 374 low = task_stack_page(p); 375 high = (struct stack_frame *) task_pt_regs(p); 376 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 377 if (sf <= low || sf > high) 378 return 0; 379 for (count = 0; count < 16; count++) { 380 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 381 if (sf <= low || sf > high) 382 return 0; 383 return_address = sf->gprs[8] & PSW_ADDR_INSN; 384 if (!in_sched_functions(return_address)) 385 return return_address; 386 } 387 return 0; 388 } 389 390