LXR linux/arch/sparc/kernel/process

   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 */
  46void (*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 */
  53void (*pm_power_off)(void) = machine_power_off;
  54EXPORT_SYMBOL(pm_power_off);
  55
  56/*
  57 * sysctl - toggle power-off restriction for serial console 
  58 * systems in machine_power_off()
  59 */
  60int scons_pwroff = 1;
  61
  62extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  63
  64struct task_struct *last_task_used_math = NULL;
  65struct thread_info *current_set[NR_CPUS];
  66
  67/* Idle loop support. */
  68void 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. */
  76void machine_halt(void)
  77{
  78        local_irq_enable();
  79        mdelay(8);
  80        local_irq_disable();
  81        prom_halt();
  82        panic("Halt failed!");
  83}
  84
  85void 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
 103void 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
 111void 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 */
 140void 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 */
 172unsigned 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 */
 180void 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
 199void 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
 230static inline struct sparc_stackf __user *
 231clone_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
 258asmlinkage 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 */
 298extern void ret_from_fork(void);
 299extern void ret_from_kernel_thread(void);
 300
 301int 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 */
 412int 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
 458unsigned 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
 485out:
 486        return ret;
 487}
 488
 489