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