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  * Note: sparc64 has a pretty intricated thread_saved_pc, check it out.
 181  */
 182 unsigned long thread_saved_pc(struct task_struct *tsk)
 183 {
 184         return task_thread_info(tsk)->kpc;
 185 }
 186
 187 /*
 188  * Free current thread data structures etc..
 189  */
 190 void exit_thread(struct task_struct *tsk)
 191 {
 192 #ifndef CONFIG_SMP
 193         if (last_task_used_math == tsk) {
 194 #else
 195         if (test_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU)) {
 196 #endif
 197                 /* Keep process from leaving FPU in a bogon state. */
 198                 put_psr(get_psr() | PSR_EF);
 199                 fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
 200                        &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
 201 #ifndef CONFIG_SMP
 202                 last_task_used_math = NULL;
 203 #else
 204                 clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
 205 #endif
 206         }
 207 }
 208
 209 void flush_thread(void)
 210 {
 211         current_thread_info()->w_saved = 0;
 212
 213 #ifndef CONFIG_SMP
 214         if(last_task_used_math == current) {
 215 #else
 216         if (test_thread_flag(TIF_USEDFPU)) {
 217 #endif
 218                 /* Clean the fpu. */
 219                 put_psr(get_psr() | PSR_EF);
 220                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 221                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 222 #ifndef CONFIG_SMP
 223                 last_task_used_math = NULL;
 224 #else
 225                 clear_thread_flag(TIF_USEDFPU);
 226 #endif
 227         }
 228
 229         /* This task is no longer a kernel thread. */
 230         if (current->thread.flags & SPARC_FLAG_KTHREAD) {
 231                 current->thread.flags &= ~SPARC_FLAG_KTHREAD;
 232
 233                 /* We must fixup kregs as well. */
 234                 /* XXX This was not fixed for ti for a while, worked. Unused? */
 235                 current->thread.kregs = (struct pt_regs *)
 236                     (task_stack_page(current) + (THREAD_SIZE - TRACEREG_SZ));
 237         }
 238 }
 239
 240 static inline struct sparc_stackf __user *
 241 clone_stackframe(struct sparc_stackf __user *dst,
 242                  struct sparc_stackf __user *src)
 243 {
 244         unsigned long size, fp;
 245         struct sparc_stackf *tmp;
 246         struct sparc_stackf __user *sp;
 247
 248         if (get_user(tmp, &src->fp))
 249                 return NULL;
 250
 251         fp = (unsigned long) tmp;
 252         size = (fp - ((unsigned long) src));
 253         fp = (unsigned long) dst;
 254         sp = (struct sparc_stackf __user *)(fp - size);
 255
 256         /* do_fork() grabs the parent semaphore, we must release it
 257          * temporarily so we can build the child clone stack frame
 258          * without deadlocking.
 259          */
 260         if (__copy_user(sp, src, size))
 261                 sp = NULL;
 262         else if (put_user(fp, &sp->fp))
 263                 sp = NULL;
 264
 265         return sp;
 266 }
 267
 268 asmlinkage int sparc_do_fork(unsigned long clone_flags,
 269                              unsigned long stack_start,
 270                              struct pt_regs *regs,
 271                              unsigned long stack_size)
 272 {
 273         unsigned long parent_tid_ptr, child_tid_ptr;
 274         unsigned long orig_i1 = regs->u_regs[UREG_I1];
 275         long ret;
 276
 277         parent_tid_ptr = regs->u_regs[UREG_I2];
 278         child_tid_ptr = regs->u_regs[UREG_I4];
 279
 280         ret = do_fork(clone_flags, stack_start, stack_size,
 281                       (int __user *) parent_tid_ptr,
 282                       (int __user *) child_tid_ptr);
 283
 284         /* If we get an error and potentially restart the system
 285          * call, we're screwed because copy_thread() clobbered
 286          * the parent's %o1.  So detect that case and restore it
 287          * here.
 288          */
 289         if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
 290                 regs->u_regs[UREG_I1] = orig_i1;
 291
 292         return ret;
 293 }
 294
 295 /* Copy a Sparc thread.  The fork() return value conventions
 296  * under SunOS are nothing short of bletcherous:
 297  * Parent -->  %o0 == childs  pid, %o1 == 0
 298  * Child  -->  %o0 == parents pid, %o1 == 1
 299  *
 300  * NOTE: We have a separate fork kpsr/kwim because
 301  *       the parent could change these values between
 302  *       sys_fork invocation and when we reach here
 303  *       if the parent should sleep while trying to
 304  *       allocate the task_struct and kernel stack in
 305  *       do_fork().
 306  * XXX See comment above sys_vfork in sparc64. todo.
 307  */
 308 extern void ret_from_fork(void);
 309 extern void ret_from_kernel_thread(void);
 310
 311 int copy_thread(unsigned long clone_flags, unsigned long sp,
 312                 unsigned long arg, struct task_struct *p)
 313 {
 314         struct thread_info *ti = task_thread_info(p);
 315         struct pt_regs *childregs, *regs = current_pt_regs();
 316         char *new_stack;
 317
 318 #ifndef CONFIG_SMP
 319         if(last_task_used_math == current) {
 320 #else
 321         if (test_thread_flag(TIF_USEDFPU)) {
 322 #endif
 323                 put_psr(get_psr() | PSR_EF);
 324                 fpsave(&p->thread.float_regs[0], &p->thread.fsr,
 325                        &p->thread.fpqueue[0], &p->thread.fpqdepth);
 326         }
 327
 328         /*
 329          *  p->thread_info         new_stack   childregs stack bottom
 330          *  !                      !           !             !
 331          *  V                      V (stk.fr.) V  (pt_regs)  V
 332          *  +----- - - - - - ------+===========+=============+
 333          */
 334         new_stack = task_stack_page(p) + THREAD_SIZE;
 335         new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
 336         childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 337
 338         /*
 339          * A new process must start with interrupts disabled, see schedule_tail()
 340          * and finish_task_switch(). (If we do not do it and if a timer interrupt
 341          * hits before we unlock and attempts to take the rq->lock, we deadlock.)
 342          *
 343          * Thus, kpsr |= PSR_PIL.
 344          */
 345         ti->ksp = (unsigned long) new_stack;
 346         p->thread.kregs = childregs;
 347
 348         if (unlikely(p->flags & PF_KTHREAD)) {
 349                 extern int nwindows;
 350                 unsigned long psr;
 351                 memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
 352                 p->thread.flags |= SPARC_FLAG_KTHREAD;
 353                 p->thread.current_ds = KERNEL_DS;
 354                 ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
 355                 childregs->u_regs[UREG_G1] = sp; /* function */
 356                 childregs->u_regs[UREG_G2] = arg;
 357                 psr = childregs->psr = get_psr();
 358                 ti->kpsr = psr | PSR_PIL;
 359                 ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
 360                 return 0;
 361         }
 362         memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 363         childregs->u_regs[UREG_FP] = sp;
 364         p->thread.flags &= ~SPARC_FLAG_KTHREAD;
 365         p->thread.current_ds = USER_DS;
 366         ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 367         ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 368         ti->kwim = current->thread.fork_kwim;
 369
 370         if (sp != regs->u_regs[UREG_FP]) {
 371                 struct sparc_stackf __user *childstack;
 372                 struct sparc_stackf __user *parentstack;
 373
 374                 /*
 375                  * This is a clone() call with supplied user stack.
 376                  * Set some valid stack frames to give to the child.
 377                  */
 378                 childstack = (struct sparc_stackf __user *)
 379                         (sp & ~0xfUL);
 380                 parentstack = (struct sparc_stackf __user *)
 381                         regs->u_regs[UREG_FP];
 382
 383 #if 0
 384                 printk("clone: parent stack:\n");
 385                 show_stackframe(parentstack);
 386 #endif
 387
 388                 childstack = clone_stackframe(childstack, parentstack);
 389                 if (!childstack)
 390                         return -EFAULT;
 391
 392 #if 0
 393                 printk("clone: child stack:\n");
 394                 show_stackframe(childstack);
 395 #endif
 396
 397                 childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 398         }
 399
 400 #ifdef CONFIG_SMP
 401         /* FPU must be disabled on SMP. */
 402         childregs->psr &= ~PSR_EF;
 403         clear_tsk_thread_flag(p, TIF_USEDFPU);
 404 #endif
 405
 406         /* Set the return value for the child. */
 407         childregs->u_regs[UREG_I0] = current->pid;
 408         childregs->u_regs[UREG_I1] = 1;
 409
 410         /* Set the return value for the parent. */
 411         regs->u_regs[UREG_I1] = 0;
 412
 413         if (clone_flags & CLONE_SETTLS)
 414                 childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
 415
 416         return 0;
 417 }
 418
 419 /*
 420  * fill in the fpu structure for a core dump.
 421  */
 422 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
 423 {
 424         if (used_math()) {
 425                 memset(fpregs, 0, sizeof(*fpregs));
 426                 fpregs->pr_q_entrysize = 8;
 427                 return 1;
 428         }
 429 #ifdef CONFIG_SMP
 430         if (test_thread_flag(TIF_USEDFPU)) {
 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                         clear_thread_flag(TIF_USEDFPU);
 437                 }
 438         }
 439 #else
 440         if (current == last_task_used_math) {
 441                 put_psr(get_psr() | PSR_EF);
 442                 fpsave(&current->thread.float_regs[0], &current->thread.fsr,
 443                        &current->thread.fpqueue[0], &current->thread.fpqdepth);
 444                 if (regs != NULL) {
 445                         regs->psr &= ~(PSR_EF);
 446                         last_task_used_math = NULL;
 447                 }
 448         }
 449 #endif
 450         memcpy(&fpregs->pr_fr.pr_regs[0],
 451                &current->thread.float_regs[0],
 452                (sizeof(unsigned long) * 32));
 453         fpregs->pr_fsr = current->thread.fsr;
 454         fpregs->pr_qcnt = current->thread.fpqdepth;
 455         fpregs->pr_q_entrysize = 8;
 456         fpregs->pr_en = 1;
 457         if(fpregs->pr_qcnt != 0) {
 458                 memcpy(&fpregs->pr_q[0],
 459                        &current->thread.fpqueue[0],
 460                        sizeof(struct fpq) * fpregs->pr_qcnt);
 461         }
 462         /* Zero out the rest. */
 463         memset(&fpregs->pr_q[fpregs->pr_qcnt], 0,
 464                sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 465         return 1;
 466 }
 467
 468 unsigned long get_wchan(struct task_struct *task)
 469 {
 470         unsigned long pc, fp, bias = 0;
 471         unsigned long task_base = (unsigned long) task;
 472         unsigned long ret = 0;
 473         struct reg_window32 *rw;
 474         int count = 0;
 475
 476         if (!task || task == current ||
 477             task->state == TASK_RUNNING)
 478                 goto out;
 479
 480         fp = task_thread_info(task)->ksp + bias;
 481         do {
 482                 /* Bogus frame pointer? */
 483                 if (fp < (task_base + sizeof(struct thread_info)) ||
 484                     fp >= (task_base + (2 * PAGE_SIZE)))
 485                         break;
 486                 rw = (struct reg_window32 *) fp;
 487                 pc = rw->ins[7];
 488                 if (!in_sched_functions(pc)) {
 489                         ret = pc;
 490                         goto out;
 491                 }
 492                 fp = rw->ins[6] + bias;
 493         } while (++count < 16);
 494
 495 out:
 496         return ret;
 497 }
 498