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/elfcore.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/stddef.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/user.h>
  22 #include <linux/smp.h>
  23 #include <linux/reboot.h>
  24 #include <linux/delay.h>
  25 #include <linux/pm.h>
  26 #include <linux/slab.h>
  27 #include <linux/cpu.h>
  28
  29 #include <asm/auxio.h>
  30 #include <asm/oplib.h>
  31 #include <linux/uaccess.h>
  32 #include <asm/page.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/delay.h>
  36 #include <asm/processor.h>
  37 #include <asm/psr.h>
  38 #include <asm/elf.h>
  39 #include <asm/prom.h>
  40 #include <asm/unistd.h>
  41 #include <asm/setup.h>
  42
  43 #include "kernel.h"
  44
  45 /*
  46  * Power management idle function
  47  * Set in pm platform drivers (apc.c and pmc.c)
  48  */
  49 void (*sparc_idle)(void);
  50
  51 /*
  52  * Power-off handler instantiation for pm.h compliance
  53  * This is done via auxio, but could be used as a fallback
  54  * handler when auxio is not present-- unused for now...
  55  */
  56 void (*pm_power_off)(void) = machine_power_off;
  57 EXPORT_SYMBOL(pm_power_off);
  58
  59 /*
  60  * sysctl - toggle power-off restriction for serial console
  61  * systems in machine_power_off()
  62  */
  63 int scons_pwroff = 1;
  64
  65 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  66
  67 struct task_struct *last_task_used_math = NULL;
  68 struct thread_info *current_set[NR_CPUS];
  69
  70 /* Idle loop support. */
  71 void arch_cpu_idle(void)
  72 {
  73         if (sparc_idle)
  74                 (*sparc_idle)();
  75         local_irq_enable();
  76 }
  77
  78 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
  79 void machine_halt(void)
  80 {
  81         local_irq_enable();
  82         mdelay(8);
  83         local_irq_disable();
  84         prom_halt();
  85         panic("Halt failed!");
  86 }
  87
  88 void machine_restart(char * cmd)
  89 {
  90         char *p;
  91
  92         local_irq_enable();
  93         mdelay(8);
  94         local_irq_disable();
  95
  96         p = strchr (reboot_command, '\n');
  97         if (p) *p = 0;
  98         if (cmd)
  99                 prom_reboot(cmd);
 100         if (*reboot_command)
 101                 prom_reboot(reboot_command);
 102         prom_feval ("reset");
 103         panic("Reboot failed!");
 104 }
 105
 106 void machine_power_off(void)
 107 {
 108         if (auxio_power_register &&
 109             (strcmp(of_console_device->type, "serial") || scons_pwroff)) {
 110                 u8 power_register = sbus_readb(auxio_power_register);
 111                 power_register |= AUXIO_POWER_OFF;
 112                 sbus_writeb(power_register, auxio_power_register);
 113         }
 114
 115         machine_halt();
 116 }
 117
 118 void show_regs(struct pt_regs *r)
 119 {
 120         struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
 121
 122         show_regs_print_info(KERN_DEFAULT);
 123
 124         printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 125                r->psr, r->pc, r->npc, r->y, print_tainted());
 126         printk("PC: <%pS>\n", (void *) r->pc);
 127         printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 128                r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 129                r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 130         printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 131                r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 132                r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 133         printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 134
 135         printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 136                rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 137                rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 138         printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 139                rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 140                rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 141 }
 142
 143 /*
 144  * The show_stack is an external API which we do not use ourselves.
 145  * The oops is printed in die_if_kernel.
 146  */
 147 void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 148 {
 149         unsigned long pc, fp;
 150         unsigned long task_base;
 151         struct reg_window32 *rw;
 152         int count = 0;
 153
 154         if (!tsk)
 155                 tsk = current;
 156
 157         if (tsk == current && !_ksp)
 158                 __asm__ __volatile__("mov       %%fp, %0" : "=r" (_ksp));
 159
 160         task_base = (unsigned long) task_stack_page(tsk);
 161         fp = (unsigned long) _ksp;
 162         do {
 163                 /* Bogus frame pointer? */
 164                 if (fp < (task_base + sizeof(struct thread_info)) ||
 165                     fp >= (task_base + (PAGE_SIZE << 1)))
 166                         break;
 167                 rw = (struct reg_window32 *) fp;
 168                 pc = rw->ins[7];
 169                 printk("[%08lx : ", pc);
 170                 printk("%pS ] ", (void *) pc);
 171                 fp = rw->ins[6];
 172         } while (++count < 16);
 173         printk("\n");
 174 }
 175
 176 /*
 177  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 178  */
 179 unsigned long thread_saved_pc(struct task_struct *tsk)
 180 {
 181         return task_thread_info(tsk)->kpc;
 182 }
 183
 184 /*
 185  * Free current thread data structures etc..
 186  */
 187 void exit_thread(struct task_struct *tsk)
 188 {
 189 #ifndef CONFIG_SMP
 190         if (last_task_used_math == tsk) {
 191 #else
 192         if (test_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU)) {
 193 #endif
 194                 /* Keep process from leaving FPU in a bogon state. */
 195                 put_psr(get_psr() | PSR_EF);
 196                 fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
 197                        &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
 198 #ifndef CONFIG_SMP
 199                 last_task_used_math = NULL;
 200 #else
 201                 clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
 202 #endif
 203         }
 204 }
 205
 206 void flush_thread(void)
 207 {
 208         current_thread_info()->w_saved = 0;
 209
 210 #ifndef CONFIG_SMP
 211         if(last_task_used_math == current) {
 212 #else
 213         if (test_thread_flag(TIF_USEDFPU)) {
 214 #endif
 215                 /* Clean the fpu. */
 216                 put_psr(get_psr() | PSR_EF);
 217                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 218                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 219 #ifndef CONFIG_SMP
 220                 last_task_used_math = NULL;
 221 #else
 222                 clear_thread_flag(TIF_USEDFPU);
 223 #endif
 224         }
 225
 226         /* This task is no longer a kernel thread. */
 227         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 228                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 229
 230                 /* We must fixup kregs as well. */
 231                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 232                 current->thread.kregs = (struct pt_regs *)
 233                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 234         }
 235 }
 236
 237 static inline struct sparc_stackf __user *
 238 clone_stackframe(struct sparc_stackf __user *dst,
 239                  struct sparc_stackf __user *src)
 240 {
 241         unsigned long size, fp;
 242         struct sparc_stackf *tmp;
 243         struct sparc_stackf __user *sp;
 244
 245         if (get_user(tmp, &src->fp))
 246                 return NULL;
 247
 248         fp = (unsigned long) tmp;
 249         size = (fp - ((unsigned long) src));
 250         fp = (unsigned long) dst;
 251         sp = (struct sparc_stackf __user *)(fp - size);
 252
 253         /* do_fork() grabs the parent semaphore, we must release it
 254          * temporarily so we can build the child clone stack frame
 255          * without deadlocking.
 256          */
 257         if (__copy_user(sp, src, size))
 258                 sp = NULL;
 259         else if (put_user(fp, &sp->fp))
 260                 sp = NULL;
 261
 262         return sp;
 263 }
 264
 265 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 266                              unsigned long stack_start,
 267                              struct pt_regs *regs,
 268                              unsigned long stack_size)
 269 {
 270         unsigned long parent_tid_ptr, child_tid_ptr;
 271         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 272         long ret;
 273
 274         parent_tid_ptr = regs->u_regs[UREG_I2];
 275         child_tid_ptr = regs->u_regs[UREG_I4];
 276
 277         ret = do_fork(clone_flags, stack_start, stack_size,
 278                       (int __user *) parent_tid_ptr,
 279                       (int __user *) child_tid_ptr);
 280
 281         /* If we get an error and potentially restart the system
 282          * call, we're screwed because copy_thread() clobbered
 283          * the parent's %o1.  So detect that case and restore it
 284          * here.
 285          */
 286         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 287                 regs->u_regs[UREG_I1] = orig_i1;
 288
 289         return ret;
 290 }
 291
 292 /* Copy a Sparc thread.  The fork() return value conventions
 293  * under SunOS are nothing short of bletcherous:
 294  * Parent -->  %o0 == childs  pid, %o1 == 0
 295  * Child  -->  %o0 == parents pid, %o1 == 1
 296  *
 297  * NOTE: We have a separate fork kpsr/kwim because
 298  *       the parent could change these values between
 299  *       sys_fork invocation and when we reach here
 300  *       if the parent should sleep while trying to
 301  *       allocate the task_struct and kernel stack in
 302  *       do_fork().
 303  * XXX See comment above sys_vfork in sparc64. todo.
 304  */
 305 extern void ret_from_fork(void);
 306 extern void ret_from_kernel_thread(void);
 307
 308 int copy_thread(unsigned long clone_flags, unsigned long sp,
 309                 unsigned long arg, struct task_struct *p)
 310 {
 311         struct thread_info *ti = task_thread_info(p);
 312         struct pt_regs *childregs, *regs = current_pt_regs();
 313         char *new_stack;
 314
 315 #ifndef CONFIG_SMP
 316         if(last_task_used_math == current) {
 317 #else
 318         if (test_thread_flag(TIF_USEDFPU)) {
 319 #endif
 320                 put_psr(get_psr() | PSR_EF);
 321                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 322                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 323         }
 324
 325         /*
 326          *  p->thread_info         new_stack   childregs stack bottom
 327          *  !                      !           !             !
 328          *  V                      V (stk.fr.) V  (pt_regs)  V
 329          *  +----- - - - - - ------+===========+=============+
 330          */
 331         new_stack = task_stack_page(p) + THREAD_SIZE;
 332         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 333         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 334
 335         /*
 336          * A new process must start with interrupts disabled, see schedule_tail()
 337          * and finish_task_switch(). (If we do not do it and if a timer interrupt
 338          * hits before we unlock and attempts to take the rq->lock, we deadlock.)
 339          *
 340          * Thus, kpsr |= PSR_PIL.
 341          */
 342         ti->ksp = (unsigned long) new_stack;
 343         p->thread.kregs = childregs;
 344
 345         if (unlikely(p->flags & PF_KTHREAD)) {
 346                 extern int nwindows;
 347                 unsigned long psr;
 348                 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 349                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 350                 p->thread.current_ds = KERNEL_DS;
 351                 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 352                 childregs->u_regs[UREG_G1] = sp; /* function */
 353                 childregs->u_regs[UREG_G2] = arg;
 354                 psr = childregs->psr = get_psr();
 355                 ti->kpsr = psr | PSR_PIL;
 356                 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 357                 return 0;
 358         }
 359         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 360         childregs->u_regs[UREG_FP] = sp;
 361         p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 362         p->thread.current_ds = USER_DS;
 363         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 364         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 365         ti->kwim = current->thread.fork_kwim;
 366
 367         if (sp != regs->u_regs[UREG_FP]) {
 368                 struct sparc_stackf __user *childstack;
 369                 struct sparc_stackf __user *parentstack;
 370
 371                 /*
 372                  * This is a clone() call with supplied user stack.
 373                  * Set some valid stack frames to give to the child.
 374                  */
 375                 childstack = (struct sparc_stackf __user *)
 376                         (sp & ~0xfUL);
 377                 parentstack = (struct sparc_stackf __user *)
 378                         regs->u_regs[UREG_FP];
 379
 380 #if 0
 381                 printk("clone: parent stack:\n");
 382                 show_stackframe(parentstack);
 383 #endif
 384
 385                 childstack = clone_stackframe(childstack, parentstack);
 386                 if (!childstack)
 387                         return -EFAULT;
 388
 389 #if 0
 390                 printk("clone: child stack:\n");
 391                 show_stackframe(childstack);
 392 #endif
 393
 394                 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 395         }
 396
 397 #ifdef CONFIG_SMP
 398         /* FPU must be disabled on SMP. */
 399         childregs->psr &= ~PSR_EF;
 400         clear_tsk_thread_flag(p, TIF_USEDFPU);
 401 #endif
 402
 403         /* Set the return value for the child. */
 404         childregs->u_regs[UREG_I0] = current->pid;
 405         childregs->u_regs[UREG_I1] = 1;
 406
 407         /* Set the return value for the parent. */
 408         regs->u_regs[UREG_I1] = 0;
 409
 410         if (clone_flags & CLONE_SETTLS)
 411                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 412
 413         return 0;
 414 }
 415
 416 /*
 417  * fill in the fpu structure for a core dump.
 418  */
 419 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 420 {
 421         if (used_math()) {
 422                 memset(fpregs, 0, sizeof(*fpregs));
 423                 fpregs->pr_q_entrysize = 8;
 424                 return 1;
 425         }
 426 #ifdef CONFIG_SMP
 427         if (test_thread_flag(TIF_USEDFPU)) {
 428                 put_psr(get_psr() | PSR_EF);
 429                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 430                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 431                 if (regs != NULL) {
 432                         regs->psr &= ~(PSR_EF);
 433                         clear_thread_flag(TIF_USEDFPU);
 434                 }
 435         }
 436 #else
 437         if (current == last_task_used_math) {
 438                 put_psr(get_psr() | PSR_EF);
 439                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 440                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 441                 if (regs != NULL) {
 442                         regs->psr &= ~(PSR_EF);
 443                         last_task_used_math = NULL;
 444                 }
 445         }
 446 #endif
 447         memcpy(&fpregs->pr_fr.pr_regs[0],
 448                &current->thread.float_regs[0],
 449                (sizeof(unsigned long) * 32));
 450         fpregs->pr_fsr = current->thread.fsr;
 451         fpregs->pr_qcnt = current->thread.fpqdepth;
 452         fpregs->pr_q_entrysize = 8;
 453         fpregs->pr_en = 1;
 454         if(fpregs->pr_qcnt != 0) {
 455                 memcpy(&fpregs->pr_q[0],
 456                        &current->thread.fpqueue[0],
 457                        sizeof(struct fpq) * fpregs->pr_qcnt);
 458         }
 459         /* Zero out the rest. */
 460         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 461                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 462         return 1;
 463 }
 464
 465 unsigned long get_wchan(struct task_struct *task)
 466 {
 467         unsigned long pc, fp, bias = 0;
 468         unsigned long task_base = (unsigned long) task;
 469         unsigned long ret = 0;
 470         struct reg_window32 *rw;
 471         int count = 0;
 472
 473         if (!task || task == current ||
 474             task->state == TASK_RUNNING)
 475                 goto out;
 476
 477         fp = task_thread_info(task)->ksp + bias;
 478         do {
 479                 /* Bogus frame pointer? */
 480                 if (fp < (task_base + sizeof(struct thread_info)) ||
 481                     fp >= (task_base + (2 * PAGE_SIZE)))
 482                         break;
 483                 rw = (struct reg_window32 *) fp;
 484                 pc = rw->ins[7];
 485                 if (!in_sched_functions(pc)) {
 486                         ret = pc;
 487                         goto out;
 488                 }
 489                 fp = rw->ins[6] + bias;
 490         } while (++count < 16);
 491
 492 out:
 493         return ret;
 494 }
 495