arch/sparc/kernel/process_32.c

   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  */
  53 void (*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  */
  60 void (*pm_power_off)(void) = machine_power_off;
  61 EXPORT_SYMBOL(pm_power_off);
  62
  63 /*
  64  * sysctl - toggle power-off restriction for serial console
  65  * systems in machine_power_off()
  66  */
  67 int scons_pwroff = 1;
  68
  69 extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
  70
  71 struct task_struct *last_task_used_math = NULL;
  72 struct thread_info *current_set[NR_CPUS];
  73
  74 /* Idle loop support. */
  75 void 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. */
  83 void machine_halt(void)
  84 {
  85         local_irq_enable();
  86         mdelay(8);
  87         local_irq_disable();
  88         prom_halt();
  89         panic("Halt failed!");
  90 }
  91
  92 void 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
 110 void 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
 122 void 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  */
 151 void 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  */
 183 void 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
 202 void 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
 233 static inline struct sparc_stackf __user *
 234 clone_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
 261 asmlinkage 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  */
 301 extern void ret_from_fork(void);
 302 extern void ret_from_kernel_thread(void);
 303
 304 int 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  */
 415 int 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
 461 unsigned 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
 488 out:
 489         return ret;
 490 }
 491