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         show_regs_print_info(KERN_DEFAULT);
 116
 117         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 118                r->psr, r->pc, r->npc, r->y, print_tainted());
 119         printk("PC: <%pS>\n", (void *) r->pc);
 120         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 121                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 122                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 123         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 124                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 125                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 126         printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 127
 128         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 129                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 130                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 131         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 132                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 133                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 134 }
 135
 136 /*
 137  * The show_stack is an external API which we do not use ourselves.
 138  * The oops is printed in die_if_kernel.
 139  */
 140 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 141 {
 142         unsigned long pc, fp;
 143         unsigned long task_base;
 144         struct reg_window32 *rw;
 145         int count = 0;
 146
 147         if (!tsk)
 148                 tsk = current;
 149
 150         if (tsk == current && !_ksp)
 151                 __asm__ __volatile__("mov       %%fp, %0" : "=r" (_ksp));
 152
 153         task_base = (unsigned long) task_stack_page(tsk);
 154         fp = (unsigned long) _ksp;
 155         do {
 156                 /* Bogus frame pointer? */
 157                 if (fp < (task_base + sizeof(struct thread_info)) ||
 158                     fp >= (task_base + (PAGE_SIZE << 1)))
 159                         break;
 160                 rw = (struct reg_window32 *) fp;
 161                 pc = rw->ins[7];
 162                 printk("[%08lx : ", pc);
 163                 printk("%pS ] ", (void *) pc);
 164                 fp = rw->ins[6];
 165         } while (++count < 16);
 166         printk("\n");
 167 }
 168
 169 /*
 170  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 171  */
 172 unsigned long thread_saved_pc(struct task_struct *tsk)
 173 {
 174         return task_thread_info(tsk)->kpc;
 175 }
 176
 177 /*
 178  * Free current thread data structures etc..
 179  */
 180 void exit_thread(void)
 181 {
 182 #ifndef CONFIG_SMP
 183         if(last_task_used_math == current) {
 184 #else
 185         if (test_thread_flag(TIF_USEDFPU)) {
 186 #endif
 187                 /* Keep process from leaving FPU in a bogon state. */
 188                 put_psr(get_psr() | PSR_EF);
 189                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 190                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 191 #ifndef CONFIG_SMP
 192                 last_task_used_math = NULL;
 193 #else
 194                 clear_thread_flag(TIF_USEDFPU);
 195 #endif
 196         }
 197 }
 198
 199 void flush_thread(void)
 200 {
 201         current_thread_info()->w_saved = 0;
 202
 203 #ifndef CONFIG_SMP
 204         if(last_task_used_math == current) {
 205 #else
 206         if (test_thread_flag(TIF_USEDFPU)) {
 207 #endif
 208                 /* Clean the fpu. */
 209                 put_psr(get_psr() | PSR_EF);
 210                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 211                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 212 #ifndef CONFIG_SMP
 213                 last_task_used_math = NULL;
 214 #else
 215                 clear_thread_flag(TIF_USEDFPU);
 216 #endif
 217         }
 218
 219         /* This task is no longer a kernel thread. */
 220         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 221                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 222
 223                 /* We must fixup kregs as well. */
 224                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 225                 current->thread.kregs = (struct pt_regs *)
 226                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 227         }
 228 }
 229
 230 static inline struct sparc_stackf __user *
 231 clone_stackframe(struct sparc_stackf __user *dst,
 232                  struct sparc_stackf __user *src)
 233 {
 234         unsigned long size, fp;
 235         struct sparc_stackf *tmp;
 236         struct sparc_stackf __user *sp;
 237
 238         if (get_user(tmp, &src->fp))
 239                 return NULL;
 240
 241         fp = (unsigned long) tmp;
 242         size = (fp - ((unsigned long) src));
 243         fp = (unsigned long) dst;
 244         sp = (struct sparc_stackf __user *)(fp - size);
 245
 246         /* do_fork() grabs the parent semaphore, we must release it
 247          * temporarily so we can build the child clone stack frame
 248          * without deadlocking.
 249          */
 250         if (__copy_user(sp, src, size))
 251                 sp = NULL;
 252         else if (put_user(fp, &sp->fp))
 253                 sp = NULL;
 254
 255         return sp;
 256 }
 257
 258 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 259                              unsigned long stack_start,
 260                              struct pt_regs *regs,
 261                              unsigned long stack_size)
 262 {
 263         unsigned long parent_tid_ptr, child_tid_ptr;
 264         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 265         long ret;
 266
 267         parent_tid_ptr = regs->u_regs[UREG_I2];
 268         child_tid_ptr = regs->u_regs[UREG_I4];
 269
 270         ret = do_fork(clone_flags, stack_start, stack_size,
 271                       (int __user *) parent_tid_ptr,
 272                       (int __user *) child_tid_ptr);
 273
 274         /* If we get an error and potentially restart the system
 275          * call, we're screwed because copy_thread() clobbered
 276          * the parent's %o1.  So detect that case and restore it
 277          * here.
 278          */
 279         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 280                 regs->u_regs[UREG_I1] = orig_i1;
 281
 282         return ret;
 283 }
 284
 285 /* Copy a Sparc thread.  The fork() return value conventions
 286  * under SunOS are nothing short of bletcherous:
 287  * Parent -->  %o0 == childs  pid, %o1 == 0
 288  * Child  -->  %o0 == parents pid, %o1 == 1
 289  *
 290  * NOTE: We have a separate fork kpsr/kwim because
 291  *       the parent could change these values between
 292  *       sys_fork invocation and when we reach here
 293  *       if the parent should sleep while trying to
 294  *       allocate the task_struct and kernel stack in
 295  *       do_fork().
 296  * XXX See comment above sys_vfork in sparc64. todo.
 297  */
 298 extern void ret_from_fork(void);
 299 extern void ret_from_kernel_thread(void);
 300
 301 int copy_thread(unsigned long clone_flags, unsigned long sp,
 302                 unsigned long arg, struct task_struct *p)
 303 {
 304         struct thread_info *ti = task_thread_info(p);
 305         struct pt_regs *childregs, *regs = current_pt_regs();
 306         char *new_stack;
 307
 308 #ifndef CONFIG_SMP
 309         if(last_task_used_math == current) {
 310 #else
 311         if (test_thread_flag(TIF_USEDFPU)) {
 312 #endif
 313                 put_psr(get_psr() | PSR_EF);
 314                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 315                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 316         }
 317
 318         /*
 319          *  p->thread_info         new_stack   childregs stack bottom
 320          *  !                      !           !             !
 321          *  V                      V (stk.fr.) V  (pt_regs)  V
 322          *  +----- - - - - - ------+===========+=============+
 323          */
 324         new_stack = task_stack_page(p) + THREAD_SIZE;
 325         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 326         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 327
 328         /*
 329          * A new process must start with interrupts closed in 2.5,
 330          * because this is how Mingo's scheduler works (see schedule_tail
 331          * and finish_arch_switch). If we do not do it, a timer interrupt hits
 332          * before we unlock, attempts to re-take the rq->lock, and then we die.
 333          * Thus, kpsr|=PSR_PIL.
 334          */
 335         ti->ksp = (unsigned long) new_stack;
 336         p->thread.kregs = childregs;
 337
 338         if (unlikely(p->flags & PF_KTHREAD)) {
 339                 extern int nwindows;
 340                 unsigned long psr;
 341                 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 342                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 343                 p->thread.current_ds = KERNEL_DS;
 344                 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 345                 childregs->u_regs[UREG_G1] = sp; /* function */
 346                 childregs->u_regs[UREG_G2] = arg;
 347                 psr = childregs->psr = get_psr();
 348                 ti->kpsr = psr | PSR_PIL;
 349                 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 350                 return 0;
 351         }
 352         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 353         childregs->u_regs[UREG_FP] = sp;
 354         p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 355         p->thread.current_ds = USER_DS;
 356         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 357         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 358         ti->kwim = current->thread.fork_kwim;
 359
 360         if (sp != regs->u_regs[UREG_FP]) {
 361                 struct sparc_stackf __user *childstack;
 362                 struct sparc_stackf __user *parentstack;
 363
 364                 /*
 365                  * This is a clone() call with supplied user stack.
 366                  * Set some valid stack frames to give to the child.
 367                  */
 368                 childstack = (struct sparc_stackf __user *)
 369                         (sp & ~0xfUL);
 370                 parentstack = (struct sparc_stackf __user *)
 371                         regs->u_regs[UREG_FP];
 372
 373 #if 0
 374                 printk("clone: parent stack:\n");
 375                 show_stackframe(parentstack);
 376 #endif
 377
 378                 childstack = clone_stackframe(childstack, parentstack);
 379                 if (!childstack)
 380                         return -EFAULT;
 381
 382 #if 0
 383                 printk("clone: child stack:\n");
 384                 show_stackframe(childstack);
 385 #endif
 386
 387                 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 388         }
 389
 390 #ifdef CONFIG_SMP
 391         /* FPU must be disabled on SMP. */
 392         childregs->psr &= ~PSR_EF;
 393         clear_tsk_thread_flag(p, TIF_USEDFPU);
 394 #endif
 395
 396         /* Set the return value for the child. */
 397         childregs->u_regs[UREG_I0] = current->pid;
 398         childregs->u_regs[UREG_I1] = 1;
 399
 400         /* Set the return value for the parent. */
 401         regs->u_regs[UREG_I1] = 0;
 402
 403         if (clone_flags & CLONE_SETTLS)
 404                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 405
 406         return 0;
 407 }
 408
 409 /*
 410  * fill in the fpu structure for a core dump.
 411  */
 412 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 413 {
 414         if (used_math()) {
 415                 memset(fpregs, 0, sizeof(*fpregs));
 416                 fpregs->pr_q_entrysize = 8;
 417                 return 1;
 418         }
 419 #ifdef CONFIG_SMP
 420         if (test_thread_flag(TIF_USEDFPU)) {
 421                 put_psr(get_psr() | PSR_EF);
 422                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 423                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 424                 if (regs != NULL) {
 425                         regs->psr &= ~(PSR_EF);
 426                         clear_thread_flag(TIF_USEDFPU);
 427                 }
 428         }
 429 #else
 430         if (current == last_task_used_math) {
 431                 put_psr(get_psr() | PSR_EF);
 432                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 433                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 434                 if (regs != NULL) {
 435                         regs->psr &= ~(PSR_EF);
 436                         last_task_used_math = NULL;
 437                 }
 438         }
 439 #endif
 440         memcpy(&fpregs->pr_fr.pr_regs[0],
 441                &current->thread.float_regs[0],
 442                (sizeof(unsigned long) * 32));
 443         fpregs->pr_fsr = current->thread.fsr;
 444         fpregs->pr_qcnt = current->thread.fpqdepth;
 445         fpregs->pr_q_entrysize = 8;
 446         fpregs->pr_en = 1;
 447         if(fpregs->pr_qcnt != 0) {
 448                 memcpy(&fpregs->pr_q[0],
 449                        &current->thread.fpqueue[0],
 450                        sizeof(struct fpq) * fpregs->pr_qcnt);
 451         }
 452         /* Zero out the rest. */
 453         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 454                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 455         return 1;
 456 }
 457
 458 unsigned long get_wchan(struct task_struct *task)
 459 {
 460         unsigned long pc, fp, bias = 0;
 461         unsigned long task_base = (unsigned long) task;
 462         unsigned long ret = 0;
 463         struct reg_window32 *rw;
 464         int count = 0;
 465
 466         if (!task || task == current ||
 467             task->state == TASK_RUNNING)
 468                 goto out;
 469
 470         fp = task_thread_info(task)->ksp + bias;
 471         do {
 472                 /* Bogus frame pointer? */
 473                 if (fp < (task_base + sizeof(struct thread_info)) ||
 474                     fp >= (task_base + (2 * PAGE_SIZE)))
 475                         break;
 476                 rw = (struct reg_window32 *) fp;
 477                 pc = rw->ins[7];
 478                 if (!in_sched_functions(pc)) {
 479                         ret = pc;
 480                         goto out;
 481                 }
 482                 fp = rw->ins[6] + bias;
 483         } while (++count < 16);
 484
 485 out:
 486         return ret;
 487 }
 488