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