arch/sparc/kernel/process_32.c

   1 /*  linux/arch/sparc/kernel/process.c
   2  *
   3  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   4  *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
   5  */
   6
   7 /*
   8  * This file handles the architecture-dependent parts of process handling..
   9  */
  10
  11 #include <stdarg.h>
  12
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/stddef.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/user.h>
  21 #include <linux/smp.h>
  22 #include <linux/reboot.h>
  23 #include <linux/delay.h>
  24 #include <linux/pm.h>
  25 #include <linux/init.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/auxio.h>
  29 #include <asm/oplib.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/page.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/delay.h>
  35 #include <asm/processor.h>
  36 #include <asm/psr.h>
  37 #include <asm/elf.h>
  38 #include <asm/prom.h>
  39 #include <asm/unistd.h>
  40 #include <asm/setup.h>
  41
  42 /*
  43  * Power management idle function
  44  * Set in pm platform drivers (apc.c and pmc.c)
  45  */
  46 void (*pm_idle)(void);
  47 EXPORT_SYMBOL(pm_idle);
  48
  49 /*
  50  * Power-off handler instantiation for pm.h compliance
  51  * This is done via auxio, but could be used as a fallback
  52  * handler when auxio is not present-- unused for now...
  53  */
  54 void (*pm_power_off)(void) = machine_power_off;
  55 EXPORT_SYMBOL(pm_power_off);
  56
  57 /*
  58  * sysctl - toggle power-off restriction for serial console
  59  * systems in machine_power_off()
  60  */
  61 int scons_pwroff = 1;
  62
  63 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  64
  65 struct task_struct *last_task_used_math = NULL;
  66 struct thread_info *current_set[NR_CPUS];
  67
  68 /*
  69  * the idle loop on a Sparc... ;)
  70  */
  71 void cpu_idle(void)
  72 {
  73         set_thread_flag(TIF_POLLING_NRFLAG);
  74
  75         /* endless idle loop with no priority at all */
  76         for (;;) {
  77                 while (!need_resched()) {
  78                         if (pm_idle)
  79                                 (*pm_idle)();
  80                         else
  81                                 cpu_relax();
  82                 }
  83                 schedule_preempt_disabled();
  84         }
  85 }
  86
  87 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
  88 void machine_halt(void)
  89 {
  90         local_irq_enable();
  91         mdelay(8);
  92         local_irq_disable();
  93         prom_halt();
  94         panic("Halt failed!");
  95 }
  96
  97 void machine_restart(char * cmd)
  98 {
  99         char *p;
 100
 101         local_irq_enable();
 102         mdelay(8);
 103         local_irq_disable();
 104
 105         p = strchr (reboot_command, '\n');
 106         if (p) *p = 0;
 107         if (cmd)
 108                 prom_reboot(cmd);
 109         if (*reboot_command)
 110                 prom_reboot(reboot_command);
 111         prom_feval ("reset");
 112         panic("Reboot failed!");
 113 }
 114
 115 void machine_power_off(void)
 116 {
 117         if (auxio_power_register &&
 118             (strcmp(of_console_device->type, "serial") || scons_pwroff))
 119                 *auxio_power_register |= AUXIO_POWER_OFF;
 120         machine_halt();
 121 }
 122
 123 void show_regs(struct pt_regs *r)
 124 {
 125         struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
 126
 127         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 128                r->psr, r->pc, r->npc, r->y, print_tainted());
 129         printk("PC: <%pS>\n", (void *) r->pc);
 130         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 131                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 132                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 133         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 134                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 135                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 136         printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 137
 138         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 139                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 140                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 141         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 142                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 143                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 144 }
 145
 146 /*
 147  * The show_stack is an external API which we do not use ourselves.
 148  * The oops is printed in die_if_kernel.
 149  */
 150 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 151 {
 152         unsigned long pc, fp;
 153         unsigned long task_base;
 154         struct reg_window32 *rw;
 155         int count = 0;
 156
 157         if (tsk != NULL)
 158                 task_base = (unsigned long) task_stack_page(tsk);
 159         else
 160                 task_base = (unsigned long) current_thread_info();
 161
 162         fp = (unsigned long) _ksp;
 163         do {
 164                 /* Bogus frame pointer? */
 165                 if (fp < (task_base + sizeof(struct thread_info)) ||
 166                     fp >= (task_base + (PAGE_SIZE << 1)))
 167                         break;
 168                 rw = (struct reg_window32 *) fp;
 169                 pc = rw->ins[7];
 170                 printk("[%08lx : ", pc);
 171                 printk("%pS ] ", (void *) pc);
 172                 fp = rw->ins[6];
 173         } while (++count < 16);
 174         printk("\n");
 175 }
 176
 177 void dump_stack(void)
 178 {
 179         unsigned long *ksp;
 180
 181         __asm__ __volatile__("mov       %%fp, %0"
 182                              : "=r" (ksp));
 183         show_stack(current, ksp);
 184 }
 185
 186 EXPORT_SYMBOL(dump_stack);
 187
 188 /*
 189  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 190  */
 191 unsigned long thread_saved_pc(struct task_struct *tsk)
 192 {
 193         return task_thread_info(tsk)->kpc;
 194 }
 195
 196 /*
 197  * Free current thread data structures etc..
 198  */
 199 void exit_thread(void)
 200 {
 201 #ifndef CONFIG_SMP
 202         if(last_task_used_math == current) {
 203 #else
 204         if (test_thread_flag(TIF_USEDFPU)) {
 205 #endif
 206                 /* Keep process from leaving FPU in a bogon state. */
 207                 put_psr(get_psr() | PSR_EF);
 208                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 209                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 210 #ifndef CONFIG_SMP
 211                 last_task_used_math = NULL;
 212 #else
 213                 clear_thread_flag(TIF_USEDFPU);
 214 #endif
 215         }
 216 }
 217
 218 void flush_thread(void)
 219 {
 220         current_thread_info()->w_saved = 0;
 221
 222 #ifndef CONFIG_SMP
 223         if(last_task_used_math == current) {
 224 #else
 225         if (test_thread_flag(TIF_USEDFPU)) {
 226 #endif
 227                 /* Clean the fpu. */
 228                 put_psr(get_psr() | PSR_EF);
 229                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 230                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 231 #ifndef CONFIG_SMP
 232                 last_task_used_math = NULL;
 233 #else
 234                 clear_thread_flag(TIF_USEDFPU);
 235 #endif
 236         }
 237
 238         /* This task is no longer a kernel thread. */
 239         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 240                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 241
 242                 /* We must fixup kregs as well. */
 243                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 244                 current->thread.kregs = (struct pt_regs *)
 245                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 246         }
 247 }
 248
 249 static inline struct sparc_stackf __user *
 250 clone_stackframe(struct sparc_stackf __user *dst,
 251                  struct sparc_stackf __user *src)
 252 {
 253         unsigned long size, fp;
 254         struct sparc_stackf *tmp;
 255         struct sparc_stackf __user *sp;
 256
 257         if (get_user(tmp, &src->fp))
 258                 return NULL;
 259
 260         fp = (unsigned long) tmp;
 261         size = (fp - ((unsigned long) src));
 262         fp = (unsigned long) dst;
 263         sp = (struct sparc_stackf __user *)(fp - size);
 264
 265         /* do_fork() grabs the parent semaphore, we must release it
 266          * temporarily so we can build the child clone stack frame
 267          * without deadlocking.
 268          */
 269         if (__copy_user(sp, src, size))
 270                 sp = NULL;
 271         else if (put_user(fp, &sp->fp))
 272                 sp = NULL;
 273
 274         return sp;
 275 }
 276
 277 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 278                              unsigned long stack_start,
 279                              struct pt_regs *regs,
 280                              unsigned long stack_size)
 281 {
 282         unsigned long parent_tid_ptr, child_tid_ptr;
 283         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 284         long ret;
 285
 286         parent_tid_ptr = regs->u_regs[UREG_I2];
 287         child_tid_ptr = regs->u_regs[UREG_I4];
 288
 289         ret = do_fork(clone_flags, stack_start,
 290                       regs, stack_size,
 291                       (int __user *) parent_tid_ptr,
 292                       (int __user *) child_tid_ptr);
 293
 294         /* If we get an error and potentially restart the system
 295          * call, we're screwed because copy_thread() clobbered
 296          * the parent's %o1.  So detect that case and restore it
 297          * here.
 298          */
 299         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 300                 regs->u_regs[UREG_I1] = orig_i1;
 301
 302         return ret;
 303 }
 304
 305 /* Copy a Sparc thread.  The fork() return value conventions
 306  * under SunOS are nothing short of bletcherous:
 307  * Parent -->  %o0 == childs  pid, %o1 == 0
 308  * Child  -->  %o0 == parents pid, %o1 == 1
 309  *
 310  * NOTE: We have a separate fork kpsr/kwim because
 311  *       the parent could change these values between
 312  *       sys_fork invocation and when we reach here
 313  *       if the parent should sleep while trying to
 314  *       allocate the task_struct and kernel stack in
 315  *       do_fork().
 316  * XXX See comment above sys_vfork in sparc64. todo.
 317  */
 318 extern void ret_from_fork(void);
 319 extern void ret_from_kernel_thread(void);
 320
 321 int copy_thread(unsigned long clone_flags, unsigned long sp,
 322                 unsigned long arg, struct task_struct *p)
 323 {
 324         struct thread_info *ti = task_thread_info(p);
 325         struct pt_regs *childregs, *regs = current_pt_regs();
 326         char *new_stack;
 327
 328 #ifndef CONFIG_SMP
 329         if(last_task_used_math == current) {
 330 #else
 331         if (test_thread_flag(TIF_USEDFPU)) {
 332 #endif
 333                 put_psr(get_psr() | PSR_EF);
 334                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 335                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 336         }
 337
 338         /*
 339          *  p->thread_info         new_stack   childregs stack bottom
 340          *  !                      !           !             !
 341          *  V                      V (stk.fr.) V  (pt_regs)  V
 342          *  +----- - - - - - ------+===========+=============+
 343          */
 344         new_stack = task_stack_page(p) + THREAD_SIZE;
 345         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 346         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 347
 348         /*
 349          * A new process must start with interrupts closed in 2.5,
 350          * because this is how Mingo's scheduler works (see schedule_tail
 351          * and finish_arch_switch). If we do not do it, a timer interrupt hits
 352          * before we unlock, attempts to re-take the rq->lock, and then we die.
 353          * Thus, kpsr|=PSR_PIL.
 354          */
 355         ti->ksp = (unsigned long) new_stack;
 356         p->thread.kregs = childregs;
 357
 358         if (unlikely(p->flags & PF_KTHREAD)) {
 359                 extern int nwindows;
 360                 unsigned long psr;
 361                 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 362                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 363                 p->thread.current_ds = KERNEL_DS;
 364                 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 365                 childregs->u_regs[UREG_G1] = sp; /* function */
 366                 childregs->u_regs[UREG_G2] = arg;
 367                 psr = childregs->psr = get_psr();
 368                 ti->kpsr = psr | PSR_PIL;
 369                 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 370                 return 0;
 371         }
 372         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 373         childregs->u_regs[UREG_FP] = sp;
 374         p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 375         p->thread.current_ds = USER_DS;
 376         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 377         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 378         ti->kwim = current->thread.fork_kwim;
 379
 380         if (sp != regs->u_regs[UREG_FP]) {
 381                 struct sparc_stackf __user *childstack;
 382                 struct sparc_stackf __user *parentstack;
 383
 384                 /*
 385                  * This is a clone() call with supplied user stack.
 386                  * Set some valid stack frames to give to the child.
 387                  */
 388                 childstack = (struct sparc_stackf __user *)
 389                         (sp & ~0xfUL);
 390                 parentstack = (struct sparc_stackf __user *)
 391                         regs->u_regs[UREG_FP];
 392
 393 #if 0
 394                 printk("clone: parent stack:\n");
 395                 show_stackframe(parentstack);
 396 #endif
 397
 398                 childstack = clone_stackframe(childstack, parentstack);
 399                 if (!childstack)
 400                         return -EFAULT;
 401
 402 #if 0
 403                 printk("clone: child stack:\n");
 404                 show_stackframe(childstack);
 405 #endif
 406
 407                 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 408         }
 409
 410 #ifdef CONFIG_SMP
 411         /* FPU must be disabled on SMP. */
 412         childregs->psr &= ~PSR_EF;
 413         clear_tsk_thread_flag(p, TIF_USEDFPU);
 414 #endif
 415
 416         /* Set the return value for the child. */
 417         childregs->u_regs[UREG_I0] = current->pid;
 418         childregs->u_regs[UREG_I1] = 1;
 419
 420         /* Set the return value for the parent. */
 421         regs->u_regs[UREG_I1] = 0;
 422
 423         if (clone_flags & CLONE_SETTLS)
 424                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 425
 426         return 0;
 427 }
 428
 429 /*
 430  * fill in the fpu structure for a core dump.
 431  */
 432 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 433 {
 434         if (used_math()) {
 435                 memset(fpregs, 0, sizeof(*fpregs));
 436                 fpregs->pr_q_entrysize = 8;
 437                 return 1;
 438         }
 439 #ifdef CONFIG_SMP
 440         if (test_thread_flag(TIF_USEDFPU)) {
 441                 put_psr(get_psr() | PSR_EF);
 442                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 443                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 444                 if (regs != NULL) {
 445                         regs->psr &= ~(PSR_EF);
 446                         clear_thread_flag(TIF_USEDFPU);
 447                 }
 448         }
 449 #else
 450         if (current == last_task_used_math) {
 451                 put_psr(get_psr() | PSR_EF);
 452                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 453                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 454                 if (regs != NULL) {
 455                         regs->psr &= ~(PSR_EF);
 456                         last_task_used_math = NULL;
 457                 }
 458         }
 459 #endif
 460         memcpy(&fpregs->pr_fr.pr_regs[0],
 461                &current->thread.float_regs[0],
 462                (sizeof(unsigned long) * 32));
 463         fpregs->pr_fsr = current->thread.fsr;
 464         fpregs->pr_qcnt = current->thread.fpqdepth;
 465         fpregs->pr_q_entrysize = 8;
 466         fpregs->pr_en = 1;
 467         if(fpregs->pr_qcnt != 0) {
 468                 memcpy(&fpregs->pr_q[0],
 469                        &current->thread.fpqueue[0],
 470                        sizeof(struct fpq) * fpregs->pr_qcnt);
 471         }
 472         /* Zero out the rest. */
 473         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 474                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 475         return 1;
 476 }
 477
 478 unsigned long get_wchan(struct task_struct *task)
 479 {
 480         unsigned long pc, fp, bias = 0;
 481         unsigned long task_base = (unsigned long) task;
 482         unsigned long ret = 0;
 483         struct reg_window32 *rw;
 484         int count = 0;
 485
 486         if (!task || task == current ||
 487             task->state == TASK_RUNNING)
 488                 goto out;
 489
 490         fp = task_thread_info(task)->ksp + bias;
 491         do {
 492                 /* Bogus frame pointer? */
 493                 if (fp < (task_base + sizeof(struct thread_info)) ||
 494                     fp >= (task_base + (2 * PAGE_SIZE)))
 495                         break;
 496                 rw = (struct reg_window32 *) fp;
 497                 pc = rw->ins[7];
 498                 if (!in_sched_functions(pc)) {
 499                         ret = pc;
 500                         goto out;
 501                 }
 502                 fp = rw->ins[6] + bias;
 503         } while (++count < 16);
 504
 505 out:
 506         return ret;
 507 }
 508