arch/s390/kernel/process.c

   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 #define __KERNEL_SYSCALLS__
  19 #include <stdarg.h>
  20
  21 #include <linux/config.h>
  22 #include <linux/errno.h>
  23 #include <linux/sched.h>
  24 #include <linux/kernel.h>
  25 #include <linux/mm.h>
  26 #include <linux/smp.h>
  27 #include <linux/smp_lock.h>
  28 #include <linux/stddef.h>
  29 #include <linux/unistd.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/malloc.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/user.h>
  34 #include <linux/a.out.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/delay.h>
  37 #include <linux/reboot.h>
  38 #include <linux/init.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/misc390.h>
  46 #include <asm/irq.h>
  47
  48 spinlock_t semaphore_wake_lock = SPIN_LOCK_UNLOCKED;
  49
  50 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
  51
  52 /*
  53  * The idle loop on a S390...
  54  */
  55
  56 static psw_t wait_psw;
  57
  58 int cpu_idle(void *unused)
  59 {
  60         /* endless idle loop with no priority at all */
  61         init_idle();
  62         current->nice = 20;
  63         current->counter = -100;
  64         wait_psw.mask = _WAIT_PSW_MASK;
  65         wait_psw.addr = (unsigned long) &&idle_wakeup | 0x80000000L;
  66         while(1) {
  67                 if (softirq_active(smp_processor_id()) &
  68                     softirq_mask(smp_processor_id())) {
  69                         do_softirq();
  70                         continue;
  71                 }
  72                 if (current->need_resched) {
  73                         schedule();
  74                         check_pgt_cache();
  75                         continue;
  76                 }
  77
  78                 /* load wait psw */
  79                 asm volatile (
  80                         "lpsw %0"
  81                         : : "m" (wait_psw) );
  82 idle_wakeup:
  83         }
  84 }
  85
  86 /*
  87   As all the register will only be made displayable to the root
  88   user ( via printk ) or checking if the uid of the user is 0 from
  89   the /proc filesystem please god this will be secure enough DJB.
  90   The lines are given one at a time so as not to chew stack space in
  91   printk on a crash & also for the proc filesystem when you get
  92   0 returned you know you've got all the lines
  93  */
  94
  95 int sprintf_regs(int line, char *buff, struct task_struct * task,
  96                  struct thread_struct *thread, struct pt_regs * regs)
  97 {
  98         int linelen=0;
  99         int regno,chaincnt;
 100         u32 backchain,prev_backchain,endchain;
 101
 102         enum
 103         {
 104                 sp_linefeed,
 105                 sp_psw,
 106                 sp_ksp,
 107                 sp_gprs,
 108                 sp_gprs1,
 109                 sp_gprs2,
 110                 sp_gprs3,
 111                 sp_gprs4,
 112                 sp_acrs,
 113                 sp_acrs1,
 114                 sp_acrs2,
 115                 sp_acrs3,
 116                 sp_acrs4,
 117                 sp_kern_backchain,
 118                 sp_kern_backchain1
 119         };
 120
 121         if(task)
 122                 thread = &task->thread;
 123         if(thread)
 124                 regs = thread->regs;
 125         switch (line) {
 126         case sp_linefeed:
 127                 linelen=sprintf(buff,"\n");
 128                 break;
 129         case sp_psw:
 130                 if(regs)
 131                         linelen = sprintf(buff,"User PSW:    %08lx %08lx\n",
 132                                           (unsigned long) regs->psw.mask,
 133                                           (unsigned long) regs->psw.addr);
 134                 else
 135                         linelen = sprintf(buff,"pt_regs=NULL some info unavailable\n");
 136                 break;
 137         case sp_ksp:
 138                 if (task)
 139                         linelen += sprintf(&buff[linelen],
 140                                            "task: %08x ", (addr_t)task);
 141                 if (thread)
 142                         linelen += sprintf(&buff[linelen],
 143                                            "thread: %08x ksp: %08x ",
 144                                            (addr_t)thread,(addr_t)thread->ksp);
 145                 if (regs)
 146                         linelen += sprintf(&buff[linelen],
 147                                            "pt_regs: %08x\n", (addr_t)regs);
 148                 break;
 149         case sp_gprs:
 150                 if (regs)
 151                         linelen = sprintf(buff,"User GPRS:\n");
 152                 break;
 153         case sp_gprs1 ... sp_gprs4:
 154                 if (regs) {
 155                         regno = (line-sp_gprs1)*4;
 156                         linelen = sprintf(buff,"%08x  %08x  %08x  %08x\n",
 157                                           regs->gprs[regno],
 158                                           regs->gprs[regno+1],
 159                                           regs->gprs[regno+2],
 160                                           regs->gprs[regno+3]);
 161                 }
 162                 break;
 163         case sp_acrs:
 164                 if (regs)
 165                         linelen = sprintf(buff,"User ACRS:\n");
 166                 break;
 167         case sp_acrs1 ... sp_acrs4:
 168                 if (regs) {
 169                         regno = (line-sp_acrs1)*4;
 170                         linelen = sprintf(buff,"%08x  %08x  %08x  %08x\n",
 171                                           regs->acrs[regno],
 172                                           regs->acrs[regno+1],
 173                                           regs->acrs[regno+2],
 174                                           regs->acrs[regno+3]);
 175                 }
 176                 break;
 177         case sp_kern_backchain:
 178                 if (thread && thread->ksp && regs)
 179                         linelen = sprintf(buff,"Kernel BackChain  CallChain    BackChain  CallChain\n");
 180                 break;
 181         default:
 182                 if(thread && thread->ksp && regs) {
 183                         backchain = (thread->ksp & PSW_ADDR_MASK);
 184                         endchain = ((backchain & (-8192)) + 8192);
 185                         prev_backchain = backchain - 1;
 186                         line -= sp_kern_backchain1;
 187                         for (chaincnt = 0; ; chaincnt++) {
 188                                 if ((backchain == 0) ||
 189                                     (backchain >= endchain) ||
 190                                     (chaincnt >= 8) ||
 191                                     (prev_backchain >= backchain))
 192                                         break;
 193                                 if ((chaincnt >> 1) == line) {
 194                                         linelen += sprintf(&buff[linelen],"%s%08x   %08x     ",
 195                                                          (chaincnt&1) ? "":"       ",
 196                                                          backchain,*(u32 *)(backchain+56));
 197                                 }
 198                                 if ((chaincnt >> 1) > line)
 199                                         break;
 200                                 prev_backchain = backchain;
 201                                 backchain = (*((u32 *)backchain)) & PSW_ADDR_MASK;
 202                         }
 203                         if (linelen)
 204                                 linelen += sprintf(&buff[linelen],"\n");
 205                 }
 206         }
 207         return linelen;
 208 }
 209
 210
 211 void show_regs(struct task_struct *task, struct thread_struct *thread,
 212                struct pt_regs *regs)
 213 {
 214         char buff[80];
 215         int line;
 216
 217         for (line = 0; sprintf_regs(line,buff,task,thread,regs); line++)
 218                 printk(buff);
 219 }
 220
 221 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 222 {
 223         int clone_arg = flags | CLONE_VM;
 224         int retval;
 225
 226         __asm__ __volatile__(
 227                 "     sr    2,2\n"
 228                 "     lr    3,%1\n"
 229                 "     l     4,%6\n"     /* load kernel stack ptr of parent */
 230                 "     svc   %b2\n"                     /* Linux system call*/
 231                 "     cl    4,%6\n"    /* compare ksp's: child or parent ? */
 232                 "     je    0f\n"                          /* parent - jump*/
 233                 "     l     15,%6\n"            /* fix kernel stack pointer*/
 234                 "     ahi   15,%7\n"
 235                 "     xc    0(96,15),0(15)\n"           /* clear save area */
 236                 "     lr    2,%4\n"                        /* load argument*/
 237                 "     lr    14,%5\n"                      /* get fn-pointer*/
 238                 "     basr  14,14\n"                             /* call fn*/
 239                 "     svc   %b3\n"                     /* Linux system call*/
 240                 "0:   lr    %0,2"
 241                 : "=a" (retval)
 242                 : "d" (clone_arg), "i" (__NR_clone), "i" (__NR_exit),
 243                   "d" (arg), "d" (fn), "i" (__LC_KERNEL_STACK) , "i" (-STACK_FRAME_OVERHEAD)
 244                 : "2", "3", "4" );
 245         return retval;
 246 }
 247
 248 /*
 249  * Free current thread data structures etc..
 250  */
 251 void exit_thread(void)
 252 {
 253 }
 254
 255 void flush_thread(void)
 256 {
 257
 258         current->used_math = 0;
 259         current->flags &= ~PF_USEDFPU;
 260 }
 261
 262 void release_thread(struct task_struct *dead_task)
 263 {
 264 }
 265
 266 int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
 267         struct task_struct * p, struct pt_regs * regs)
 268 {
 269         struct stack_frame
 270           {
 271             unsigned long back_chain;
 272             unsigned long eos;
 273             unsigned long glue1;
 274             unsigned long glue2;
 275             unsigned long scratch[2];
 276             unsigned long gprs[10];    /* gprs 6 -15                       */
 277             unsigned long fprs[4];     /* fpr 4 and 6                      */
 278             unsigned long empty[4];
 279 #if CONFIG_REMOTE_DEBUG
 280             gdb_pt_regs childregs;
 281 #else
 282             pt_regs childregs;
 283 #endif
 284             __u32   pgm_old_ilc;       /* single step magic from entry.S */
 285             __u32   pgm_svc_step;
 286           } *frame;
 287
 288         frame = (struct stack_frame *) (2*PAGE_SIZE + (unsigned long) p) -1;
 289         frame = (struct stack_frame *) (((unsigned long) frame)&-8L);
 290         p->thread.regs = &frame->childregs;
 291         p->thread.ksp = (unsigned long) frame;
 292         frame->childregs = *regs;
 293         frame->childregs.gprs[15] = new_stackp;
 294         frame->eos = 0;
 295
 296         /* new return point is ret_from_sys_call */
 297         frame->gprs[8] = ((unsigned long) &ret_from_fork) | 0x80000000;
 298
 299         /* fake return stack for resume(), don't go back to schedule */
 300         frame->gprs[9]  = (unsigned long) frame;
 301         frame->pgm_svc_step = 0; /* Nope we aren't single stepping an svc */
 302         /* save fprs, if used in last task */
 303         save_fp_regs(&p->thread.fp_regs);
 304         p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
 305         p->thread.fs = USER_DS;
 306         /* Don't copy debug registers */
 307         memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
 308         return 0;
 309 }
 310
 311 asmlinkage int sys_fork(struct pt_regs regs)
 312 {
 313         int ret;
 314
 315         lock_kernel();
 316         ret = do_fork(SIGCHLD, regs.gprs[15], &regs);
 317         unlock_kernel();
 318         return ret;
 319 }
 320
 321 asmlinkage int sys_clone(struct pt_regs regs)
 322 {
 323         unsigned long clone_flags;
 324         unsigned long newsp;
 325         int ret;
 326
 327         lock_kernel();
 328         clone_flags = regs.gprs[3];
 329         newsp = regs.gprs[2];
 330         if (!newsp)
 331                 newsp = regs.gprs[15];
 332         ret = do_fork(clone_flags, newsp, &regs);
 333         unlock_kernel();
 334         return ret;
 335 }
 336
 337 /*
 338  * This is trivial, and on the face of it looks like it
 339  * could equally well be done in user mode.
 340  *
 341  * Not so, for quite unobvious reasons - register pressure.
 342  * In user mode vfork() cannot have a stack frame, and if
 343  * done by calling the "clone()" system call directly, you
 344  * do not have enough call-clobbered registers to hold all
 345  * the information you need.
 346  */
 347 asmlinkage int sys_vfork(struct pt_regs regs)
 348 {
 349         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 350                        regs.gprs[15], &regs);
 351 }
 352
 353 /*
 354  * sys_execve() executes a new program.
 355  */
 356 asmlinkage int sys_execve(struct pt_regs regs)
 357 {
 358         int error;
 359         char * filename;
 360
 361         filename = getname((char *) regs.orig_gpr2);
 362         error = PTR_ERR(filename);
 363         if (IS_ERR(filename))
 364                 goto out;
 365         error = do_execve(filename, (char **) regs.gprs[3], (char **) regs.gprs[4], &regs);
 366         if (error == 0)
 367                 current->flags &= ~PF_DTRACE;
 368         putname(filename);
 369 out:
 370         return error;
 371 }
 372
 373
 374 /*
 375  * fill in the FPU structure for a core dump.
 376  */
 377 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
 378 {
 379         save_fp_regs(fpregs);
 380         return 1;
 381 }
 382
 383 /*
 384  * fill in the user structure for a core dump..
 385  */
 386 void dump_thread(struct pt_regs * regs, struct user * dump)
 387 {
 388
 389 /* changed the size calculations - should hopefully work better. lbt */
 390         dump->magic = CMAGIC;
 391         dump->start_code = 0;
 392         dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
 393         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 394         dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
 395         dump->u_dsize -= dump->u_tsize;
 396         dump->u_ssize = 0;
 397         if (dump->start_stack < TASK_SIZE)
 398                 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
 399         memcpy(&dump->regs.gprs[0],regs,sizeof(s390_regs));
 400         dump_fpu (regs, &dump->regs.fp_regs);
 401         memcpy(&dump->regs.per_info,&current->thread.per_info,sizeof(per_struct));
 402 }
 403
 404 /*
 405  * These bracket the sleeping functions..
 406  */
 407 extern void scheduling_functions_start_here(void);
 408 extern void scheduling_functions_end_here(void);
 409 #define first_sched     ((unsigned long) scheduling_functions_start_here)
 410 #define last_sched      ((unsigned long) scheduling_functions_end_here)
 411
 412 unsigned long get_wchan(struct task_struct *p)
 413 {
 414         unsigned long r14, r15;
 415         unsigned long stack_page;
 416         int count = 0;
 417         if (!p || p == current || p->state == TASK_RUNNING)
 418                 return 0;
 419         stack_page = (unsigned long) p;
 420         r15 = p->thread.ksp;
 421         do {
 422                 r14 = *(unsigned long *) (r15+56);
 423                 if (r14 < first_sched || r14 >= last_sched)
 424                         return r14;
 425                 r15 = *(unsigned long *) (r15+60);
 426         } while (count++ < 16);
 427         return 0;
 428 }
 429 #undef last_sched
 430 #undef first_sched
 431