LXR linux/arch/sparc/kernel/process

   1// SPDX-License-Identifier: GPL-2.0
   2/*  linux/arch/sparc/kernel/process.c
   3 *
   4 *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   5 *  Copyright (C) 1996 Eddie C. Dost   (ecd@skynet.be)
   6 */
   7
   8/*
   9 * This file handles the architecture-dependent parts of process handling..
  10 */
  11
  12#include <stdarg.h>
  13
  14#include <linux/elfcore.h>
  15#include <linux/errno.h>
  16#include <linux/module.h>
  17#include <linux/sched.h>
  18#include <linux/sched/debug.h>
  19#include <linux/sched/task.h>
  20#include <linux/sched/task_stack.h>
  21#include <linux/kernel.h>
  22#include <linux/mm.h>
  23#include <linux/stddef.h>
  24#include <linux/ptrace.h>
  25#include <linux/user.h>
  26#include <linux/smp.h>
  27#include <linux/reboot.h>
  28#include <linux/delay.h>
  29#include <linux/pm.h>
  30#include <linux/slab.h>
  31#include <linux/cpu.h>
  32
  33#include <asm/auxio.h>
  34#include <asm/oplib.h>
  35#include <linux/uaccess.h>
  36#include <asm/page.h>
  37#include <asm/pgalloc.h>
  38#include <asm/pgtable.h>
  39#include <asm/delay.h>
  40#include <asm/processor.h>
  41#include <asm/psr.h>
  42#include <asm/elf.h>
  43#include <asm/prom.h>
  44#include <asm/unistd.h>
  45#include <asm/setup.h>
  46
  47#include "kernel.h"
  48
  49/* 
  50 * Power management idle function 
  51 * Set in pm platform drivers (apc.c and pmc.c)
  52 */
  53void (*sparc_idle)(void);
  54
  55/* 
  56 * Power-off handler instantiation for pm.h compliance
  57 * This is done via auxio, but could be used as a fallback
  58 * handler when auxio is not present-- unused for now...
  59 */
  60void (*pm_power_off)(void) = machine_power_off;
  61EXPORT_SYMBOL(pm_power_off);
  62
  63/*
  64 * sysctl - toggle power-off restriction for serial console 
  65 * systems in machine_power_off()
  66 */
  67int scons_pwroff = 1;
  68
  69extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  70
  71struct task_struct *last_task_used_math = NULL;
  72struct thread_info *current_set[NR_CPUS];
  73
  74/* Idle loop support. */
  75void arch_cpu_idle(void)
  76{
  77        if (sparc_idle)
  78                (*sparc_idle)();
  79        local_irq_enable();
  80}
  81
  82/* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */
  83void machine_halt(void)
  84{
  85        local_irq_enable();
  86        mdelay(8);
  87        local_irq_disable();
  88        prom_halt();
  89        panic("Halt failed!");
  90}
  91
  92void machine_restart(char * cmd)
  93{
  94        char *p;
  95        
  96        local_irq_enable();
  97        mdelay(8);
  98        local_irq_disable();
  99
 100        p = strchr (reboot_command, '\n');
 101        if (p) *p = 0;
 102        if (cmd)
 103                prom_reboot(cmd);
 104        if (*reboot_command)
 105                prom_reboot(reboot_command);
 106        prom_feval ("reset");
 107        panic("Reboot failed!");
 108}
 109
 110void machine_power_off(void)
 111{
 112        if (auxio_power_register &&
 113            (!of_node_is_type(of_console_device, "serial") || scons_pwroff)) {
 114                u8 power_register = sbus_readb(auxio_power_register);
 115                power_register |= AUXIO_POWER_OFF;
 116                sbus_writeb(power_register, auxio_power_register);
 117        }
 118
 119        machine_halt();
 120}
 121
 122void show_regs(struct pt_regs *r)
 123{
 124        struct reg_window32 *rw = (struct reg_window32 *) r->u_regs[14];
 125
 126        show_regs_print_info(KERN_DEFAULT);
 127
 128        printk("PSR: %08lx PC: %08lx NPC: %08lx Y: %08lx    %s\n",
 129               r->psr, r->pc, r->npc, r->y, print_tainted());
 130        printk("PC: <%pS>\n", (void *) r->pc);
 131        printk("%%G: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 132               r->u_regs[0], r->u_regs[1], r->u_regs[2], r->u_regs[3],
 133               r->u_regs[4], r->u_regs[5], r->u_regs[6], r->u_regs[7]);
 134        printk("%%O: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 135               r->u_regs[8], r->u_regs[9], r->u_regs[10], r->u_regs[11],
 136               r->u_regs[12], r->u_regs[13], r->u_regs[14], r->u_regs[15]);
 137        printk("RPC: <%pS>\n", (void *) r->u_regs[15]);
 138
 139        printk("%%L: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 140               rw->locals[0], rw->locals[1], rw->locals[2], rw->locals[3],
 141               rw->locals[4], rw->locals[5], rw->locals[6], rw->locals[7]);
 142        printk("%%I: %08lx %08lx  %08lx %08lx  %08lx %08lx  %08lx %08lx\n",
 143               rw->ins[0], rw->ins[1], rw->ins[2], rw->ins[3],
 144               rw->ins[4], rw->ins[5], rw->ins[6], rw->ins[7]);
 145}
 146
 147/*
 148 * The show_stack is an external API which we do not use ourselves.
 149 * The oops is printed in die_if_kernel.
 150 */
 151void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 152{
 153        unsigned long pc, fp;
 154        unsigned long task_base;
 155        struct reg_window32 *rw;
 156        int count = 0;
 157
 158        if (!tsk)
 159                tsk = current;
 160
 161        if (tsk == current && !_ksp)
 162                __asm__ __volatile__("mov       %%fp, %0" : "=r" (_ksp));
 163
 164        task_base = (unsigned long) task_stack_page(tsk);
 165        fp = (unsigned long) _ksp;
 166        do {
 167                /* Bogus frame pointer? */
 168                if (fp < (task_base + sizeof(struct thread_info)) ||
 169                    fp >= (task_base + (PAGE_SIZE << 1)))
 170                        break;
 171                rw = (struct reg_window32 *) fp;
 172                pc = rw->ins[7];
 173                printk("[%08lx : ", pc);
 174                printk("%pS ] ", (void *) pc);
 175                fp = rw->ins[6];
 176        } while (++count < 16);
 177        printk("\n");
 178}
 179
 180/*
 181 * Free current thread data structures etc..
 182 */
 183void exit_thread(struct task_struct *tsk)
 184{
 185#ifndef CONFIG_SMP
 186        if (last_task_used_math == tsk) {
 187#else
 188        if (test_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU)) {
 189#endif
 190                /* Keep process from leaving FPU in a bogon state. */
 191                put_psr(get_psr() | PSR_EF);
 192                fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
 193                       &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
 194#ifndef CONFIG_SMP
 195                last_task_used_math = NULL;
 196#else
 197                clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
 198#endif
 199        }
 200}
 201
 202void flush_thread(void)
 203{
 204        current_thread_info()->w_saved = 0;
 205
 206#ifndef CONFIG_SMP
 207        if(last_task_used_math == current) {
 208#else
 209        if (test_thread_flag(TIF_USEDFPU)) {
 210#endif
 211                /* Clean the fpu. */
 212                put_psr(get_psr() | PSR_EF);
 213                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 214                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 215#ifndef CONFIG_SMP
 216                last_task_used_math = NULL;
 217#else
 218                clear_thread_flag(TIF_USEDFPU);
 219#endif
 220        }
 221
 222        /* This task is no longer a kernel thread. */
 223        if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 224                current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 225
 226                /* We must fixup kregs as well. */
 227                /* XXX This was not fixed for ti for a while, worked. Unused? */
 228                current->thread.kregs = (struct pt_regs *)
 229                    (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 230        }
 231}
 232
 233static inline struct sparc_stackf __user *
 234clone_stackframe(struct sparc_stackf __user *dst,
 235                 struct sparc_stackf __user *src)
 236{
 237        unsigned long size, fp;
 238        struct sparc_stackf *tmp;
 239        struct sparc_stackf __user *sp;
 240
 241        if (get_user(tmp, &src->fp))
 242                return NULL;
 243
 244        fp = (unsigned long) tmp;
 245        size = (fp - ((unsigned long) src));
 246        fp = (unsigned long) dst;
 247        sp = (struct sparc_stackf __user *)(fp - size); 
 248
 249        /* do_fork() grabs the parent semaphore, we must release it
 250         * temporarily so we can build the child clone stack frame
 251         * without deadlocking.
 252         */
 253        if (__copy_user(sp, src, size))
 254                sp = NULL;
 255        else if (put_user(fp, &sp->fp))
 256                sp = NULL;
 257
 258        return sp;
 259}
 260
 261asmlinkage int sparc_do_fork(unsigned long clone_flags,
 262                             unsigned long stack_start,
 263                             struct pt_regs *regs,
 264                             unsigned long stack_size)
 265{
 266        unsigned long parent_tid_ptr, child_tid_ptr;
 267        unsigned long orig_i1 = regs->u_regs[UREG_I1];
 268        long ret;
 269
 270        parent_tid_ptr = regs->u_regs[UREG_I2];
 271        child_tid_ptr = regs->u_regs[UREG_I4];
 272
 273        ret = do_fork(clone_flags, stack_start, stack_size,
 274                      (int __user *) parent_tid_ptr,
 275                      (int __user *) child_tid_ptr);
 276
 277        /* If we get an error and potentially restart the system
 278         * call, we're screwed because copy_thread() clobbered
 279         * the parent's %o1.  So detect that case and restore it
 280         * here.
 281         */
 282        if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 283                regs->u_regs[UREG_I1] = orig_i1;
 284
 285        return ret;
 286}
 287
 288/* Copy a Sparc thread.  The fork() return value conventions
 289 * under SunOS are nothing short of bletcherous:
 290 * Parent -->  %o0 == childs  pid, %o1 == 0
 291 * Child  -->  %o0 == parents pid, %o1 == 1
 292 *
 293 * NOTE: We have a separate fork kpsr/kwim because
 294 *       the parent could change these values between
 295 *       sys_fork invocation and when we reach here
 296 *       if the parent should sleep while trying to
 297 *       allocate the task_struct and kernel stack in
 298 *       do_fork().
 299 * XXX See comment above sys_vfork in sparc64. todo.
 300 */
 301extern void ret_from_fork(void);
 302extern void ret_from_kernel_thread(void);
 303
 304int copy_thread(unsigned long clone_flags, unsigned long sp,
 305                unsigned long arg, struct task_struct *p)
 306{
 307        struct thread_info *ti = task_thread_info(p);
 308        struct pt_regs *childregs, *regs = current_pt_regs();
 309        char *new_stack;
 310
 311#ifndef CONFIG_SMP
 312        if(last_task_used_math == current) {
 313#else
 314        if (test_thread_flag(TIF_USEDFPU)) {
 315#endif
 316                put_psr(get_psr() | PSR_EF);
 317                fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 318                       &p->thread.fpqueue[0], &p->thread.fpqdepth);
 319        }
 320
 321        /*
 322         *  p->thread_info         new_stack   childregs stack bottom
 323         *  !                      !           !             !
 324         *  V                      V (stk.fr.) V  (pt_regs)  V
 325         *  +----- - - - - - ------+===========+=============+
 326         */
 327        new_stack = task_stack_page(p) + THREAD_SIZE;
 328        new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 329        childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 330
 331        /*
 332         * A new process must start with interrupts disabled, see schedule_tail()
 333         * and finish_task_switch(). (If we do not do it and if a timer interrupt
 334         * hits before we unlock and attempts to take the rq->lock, we deadlock.)
 335         *
 336         * Thus, kpsr |= PSR_PIL.
 337         */
 338        ti->ksp = (unsigned long) new_stack;
 339        p->thread.kregs = childregs;
 340
 341        if (unlikely(p->flags & PF_KTHREAD)) {
 342                extern int nwindows;
 343                unsigned long psr;
 344                memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 345                p->thread.flags |= SPARC_FLAG_KTHREAD;
 346                p->thread.current_ds = KERNEL_DS;
 347                ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 348                childregs->u_regs[UREG_G1] = sp; /* function */
 349                childregs->u_regs[UREG_G2] = arg;
 350                psr = childregs->psr = get_psr();
 351                ti->kpsr = psr | PSR_PIL;
 352                ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 353                return 0;
 354        }
 355        memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 356        childregs->u_regs[UREG_FP] = sp;
 357        p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 358        p->thread.current_ds = USER_DS;
 359        ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 360        ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 361        ti->kwim = current->thread.fork_kwim;
 362
 363        if (sp != regs->u_regs[UREG_FP]) {
 364                struct sparc_stackf __user *childstack;
 365                struct sparc_stackf __user *parentstack;
 366
 367                /*
 368                 * This is a clone() call with supplied user stack.
 369                 * Set some valid stack frames to give to the child.
 370                 */
 371                childstack = (struct sparc_stackf __user *)
 372                        (sp & ~0xfUL);
 373                parentstack = (struct sparc_stackf __user *)
 374                        regs->u_regs[UREG_FP];
 375
 376#if 0
 377                printk("clone: parent stack:\n");
 378                show_stackframe(parentstack);
 379#endif
 380
 381                childstack = clone_stackframe(childstack, parentstack);
 382                if (!childstack)
 383                        return -EFAULT;
 384
 385#if 0
 386                printk("clone: child stack:\n");
 387                show_stackframe(childstack);
 388#endif
 389
 390                childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 391        }
 392
 393#ifdef CONFIG_SMP
 394        /* FPU must be disabled on SMP. */
 395        childregs->psr &= ~PSR_EF;
 396        clear_tsk_thread_flag(p, TIF_USEDFPU);
 397#endif
 398
 399        /* Set the return value for the child. */
 400        childregs->u_regs[UREG_I0] = current->pid;
 401        childregs->u_regs[UREG_I1] = 1;
 402
 403        /* Set the return value for the parent. */
 404        regs->u_regs[UREG_I1] = 0;
 405
 406        if (clone_flags & CLONE_SETTLS)
 407                childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 408
 409        return 0;
 410}
 411
 412/*
 413 * fill in the fpu structure for a core dump.
 414 */
 415int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 416{
 417        if (used_math()) {
 418                memset(fpregs, 0, sizeof(*fpregs));
 419                fpregs->pr_q_entrysize = 8;
 420                return 1;
 421        }
 422#ifdef CONFIG_SMP
 423        if (test_thread_flag(TIF_USEDFPU)) {
 424                put_psr(get_psr() | PSR_EF);
 425                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 426                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 427                if (regs != NULL) {
 428                        regs->psr &= ~(PSR_EF);
 429                        clear_thread_flag(TIF_USEDFPU);
 430                }
 431        }
 432#else
 433        if (current == last_task_used_math) {
 434                put_psr(get_psr() | PSR_EF);
 435                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 436                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
 437                if (regs != NULL) {
 438                        regs->psr &= ~(PSR_EF);
 439                        last_task_used_math = NULL;
 440                }
 441        }
 442#endif
 443        memcpy(&fpregs->pr_fr.pr_regs[0],
 444               &current->thread.float_regs[0],
 445               (sizeof(unsigned long) * 32));
 446        fpregs->pr_fsr = current->thread.fsr;
 447        fpregs->pr_qcnt = current->thread.fpqdepth;
 448        fpregs->pr_q_entrysize = 8;
 449        fpregs->pr_en = 1;
 450        if(fpregs->pr_qcnt != 0) {
 451                memcpy(&fpregs->pr_q[0],
 452                       &current->thread.fpqueue[0],
 453                       sizeof(struct fpq) * fpregs->pr_qcnt);
 454        }
 455        /* Zero out the rest. */
 456        memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 457               sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 458        return 1;
 459}
 460
 461unsigned long get_wchan(struct task_struct *task)
 462{
 463        unsigned long pc, fp, bias = 0;
 464        unsigned long task_base = (unsigned long) task;
 465        unsigned long ret = 0;
 466        struct reg_window32 *rw;
 467        int count = 0;
 468
 469        if (!task || task == current ||
 470            task->state == TASK_RUNNING)
 471                goto out;
 472
 473        fp = task_thread_info(task)->ksp + bias;
 474        do {
 475                /* Bogus frame pointer? */
 476                if (fp < (task_base + sizeof(struct thread_info)) ||
 477                    fp >= (task_base + (2 * PAGE_SIZE)))
 478                        break;
 479                rw = (struct reg_window32 *) fp;
 480                pc = rw->ins[7];
 481                if (!in_sched_functions(pc)) {
 482                        ret = pc;
 483                        goto out;
 484                }
 485                fp = rw->ins[6] + bias;
 486        } while (++count < 16);
 487
 488out:
 489        return ret;
 490}
 491
 492