arch/frv/kernel/process.c

   1 /* process.c: FRV specific parts of process handling
   2  *
   3  * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * - Derived from arch/m68k/kernel/process.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/errno.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/smp.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/stddef.h>
  21 #include <linux/unistd.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/slab.h>
  24 #include <linux/user.h>
  25 #include <linux/elf.h>
  26 #include <linux/reboot.h>
  27 #include <linux/interrupt.h>
  28
  29 #include <asm/uaccess.h>
  30 #include <asm/system.h>
  31 #include <asm/setup.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/gdb-stub.h>
  34 #include <asm/mb-regs.h>
  35
  36 #include "local.h"
  37
  38 asmlinkage void ret_from_fork(void);
  39
  40 #include <asm/pgalloc.h>
  41
  42 void (*pm_power_off)(void);
  43 EXPORT_SYMBOL(pm_power_off);
  44
  45 struct task_struct *alloc_task_struct(void)
  46 {
  47         struct task_struct *p = kmalloc(THREAD_SIZE, GFP_KERNEL);
  48         if (p)
  49                 atomic_set((atomic_t *)(p+1), 1);
  50         return p;
  51 }
  52
  53 void free_task_struct(struct task_struct *p)
  54 {
  55         if (atomic_dec_and_test((atomic_t *)(p+1)))
  56                 kfree(p);
  57 }
  58
  59 static void core_sleep_idle(void)
  60 {
  61 #ifdef LED_DEBUG_SLEEP
  62         /* Show that we're sleeping... */
  63         __set_LEDS(0x55aa);
  64 #endif
  65         frv_cpu_core_sleep();
  66 #ifdef LED_DEBUG_SLEEP
  67         /* ... and that we woke up */
  68         __set_LEDS(0);
  69 #endif
  70         mb();
  71 }
  72
  73 void (*idle)(void) = core_sleep_idle;
  74
  75 /*
  76  * The idle thread. There's no useful work to be
  77  * done, so just try to conserve power and have a
  78  * low exit latency (ie sit in a loop waiting for
  79  * somebody to say that they'd like to reschedule)
  80  */
  81 void cpu_idle(void)
  82 {
  83         int cpu = smp_processor_id();
  84
  85         /* endless idle loop with no priority at all */
  86         while (1) {
  87                 while (!need_resched()) {
  88                         irq_stat[cpu].idle_timestamp = jiffies;
  89
  90                         if (!frv_dma_inprogress && idle)
  91                                 idle();
  92                 }
  93
  94                 preempt_enable_no_resched();
  95                 schedule();
  96                 preempt_disable();
  97         }
  98 }
  99
 100 void machine_restart(char * __unused)
 101 {
 102         unsigned long reset_addr;
 103 #ifdef CONFIG_GDBSTUB
 104         gdbstub_exit(0);
 105 #endif
 106
 107         if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
 108                 reset_addr = 0xfefff500;
 109         else
 110                 reset_addr = 0xfeff0500;
 111
 112         /* Software reset. */
 113         asm volatile("      dcef @(gr0,gr0),1 ! membar !"
 114                      "      sti     %1,@(%0,0) !"
 115                      "      nop ! nop ! nop ! nop ! nop ! "
 116                      "      nop ! nop ! nop ! nop ! nop ! "
 117                      "      nop ! nop ! nop ! nop ! nop ! "
 118                      "      nop ! nop ! nop ! nop ! nop ! "
 119                      : : "r" (reset_addr), "r" (1) );
 120
 121         for (;;)
 122                 ;
 123 }
 124
 125 void machine_halt(void)
 126 {
 127 #ifdef CONFIG_GDBSTUB
 128         gdbstub_exit(0);
 129 #endif
 130
 131         for (;;);
 132 }
 133
 134 void machine_power_off(void)
 135 {
 136 #ifdef CONFIG_GDBSTUB
 137         gdbstub_exit(0);
 138 #endif
 139
 140         for (;;);
 141 }
 142
 143 void flush_thread(void)
 144 {
 145 #if 0 //ndef NO_FPU
 146         unsigned long zero = 0;
 147 #endif
 148         set_fs(USER_DS);
 149 }
 150
 151 inline unsigned long user_stack(const struct pt_regs *regs)
 152 {
 153         while (regs->next_frame)
 154                 regs = regs->next_frame;
 155         return user_mode(regs) ? regs->sp : 0;
 156 }
 157
 158 asmlinkage int sys_fork(void)
 159 {
 160 #ifndef CONFIG_MMU
 161         /* fork almost works, enough to trick you into looking elsewhere:-( */
 162         return -EINVAL;
 163 #else
 164         return do_fork(SIGCHLD, user_stack(__frame), __frame, 0, NULL, NULL);
 165 #endif
 166 }
 167
 168 asmlinkage int sys_vfork(void)
 169 {
 170         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, user_stack(__frame), __frame, 0,
 171                        NULL, NULL);
 172 }
 173
 174 /*****************************************************************************/
 175 /*
 176  * clone a process
 177  * - tlsptr is retrieved by copy_thread()
 178  */
 179 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 180                          int __user *parent_tidptr, int __user *child_tidptr,
 181                          int __user *tlsptr)
 182 {
 183         if (!newsp)
 184                 newsp = user_stack(__frame);
 185         return do_fork(clone_flags, newsp, __frame, 0, parent_tidptr, child_tidptr);
 186 } /* end sys_clone() */
 187
 188 /*****************************************************************************/
 189 /*
 190  * This gets called before we allocate a new thread and copy
 191  * the current task into it.
 192  */
 193 void prepare_to_copy(struct task_struct *tsk)
 194 {
 195         //unlazy_fpu(tsk);
 196 } /* end prepare_to_copy() */
 197
 198 /*****************************************************************************/
 199 /*
 200  * set up the kernel stack and exception frames for a new process
 201  */
 202 int copy_thread(int nr, unsigned long clone_flags,
 203                 unsigned long usp, unsigned long topstk,
 204                 struct task_struct *p, struct pt_regs *regs)
 205 {
 206         struct pt_regs *childregs0, *childregs, *regs0;
 207
 208         regs0 = __kernel_frame0_ptr;
 209         childregs0 = (struct pt_regs *)
 210                 (task_stack_page(p) + THREAD_SIZE - USER_CONTEXT_SIZE);
 211         childregs = childregs0;
 212
 213         /* set up the userspace frame (the only place that the USP is stored) */
 214         *childregs0 = *regs0;
 215
 216         childregs0->gr8         = 0;
 217         childregs0->sp          = usp;
 218         childregs0->next_frame  = NULL;
 219
 220         /* set up the return kernel frame if called from kernel_thread() */
 221         if (regs != regs0) {
 222                 childregs--;
 223                 *childregs = *regs;
 224                 childregs->sp = (unsigned long) childregs0;
 225                 childregs->next_frame = childregs0;
 226                 childregs->gr15 = (unsigned long) task_thread_info(p);
 227                 childregs->gr29 = (unsigned long) p;
 228         }
 229
 230         p->set_child_tid = p->clear_child_tid = NULL;
 231
 232         p->thread.frame  = childregs;
 233         p->thread.curr   = p;
 234         p->thread.sp     = (unsigned long) childregs;
 235         p->thread.fp     = 0;
 236         p->thread.lr     = 0;
 237         p->thread.pc     = (unsigned long) ret_from_fork;
 238         p->thread.frame0 = childregs0;
 239
 240         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 241         if (clone_flags & CLONE_SETTLS)
 242                 childregs->gr29 = childregs->gr12;
 243
 244         save_user_regs(p->thread.user);
 245
 246         return 0;
 247 } /* end copy_thread() */
 248
 249 /*
 250  * sys_execve() executes a new program.
 251  */
 252 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 253 {
 254         int error;
 255         char * filename;
 256
 257         lock_kernel();
 258         filename = getname(name);
 259         error = PTR_ERR(filename);
 260         if (IS_ERR(filename))
 261                 goto out;
 262         error = do_execve(filename, argv, envp, __frame);
 263         putname(filename);
 264  out:
 265         unlock_kernel();
 266         return error;
 267 }
 268
 269 unsigned long get_wchan(struct task_struct *p)
 270 {
 271         struct pt_regs *regs0;
 272         unsigned long fp, pc;
 273         unsigned long stack_limit;
 274         int count = 0;
 275         if (!p || p == current || p->state == TASK_RUNNING)
 276                 return 0;
 277
 278         stack_limit = (unsigned long) (p + 1);
 279         fp = p->thread.fp;
 280         regs0 = p->thread.frame0;
 281
 282         do {
 283                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 284                         return 0;
 285
 286                 pc = ((unsigned long *) fp)[2];
 287
 288                 /* FIXME: This depends on the order of these functions. */
 289                 if (!in_sched_functions(pc))
 290                         return pc;
 291
 292                 fp = *(unsigned long *) fp;
 293         } while (count++ < 16);
 294
 295         return 0;
 296 }
 297
 298 unsigned long thread_saved_pc(struct task_struct *tsk)
 299 {
 300         /* Check whether the thread is blocked in resume() */
 301         if (in_sched_functions(tsk->thread.pc))
 302                 return ((unsigned long *)tsk->thread.fp)[2];
 303         else
 304                 return tsk->thread.pc;
 305 }
 306
 307 int elf_check_arch(const struct elf32_hdr *hdr)
 308 {
 309         unsigned long hsr0 = __get_HSR(0);
 310         unsigned long psr = __get_PSR();
 311
 312         if (hdr->e_machine != EM_FRV)
 313                 return 0;
 314
 315         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 316         case EF_FRV_GPR64:
 317                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 318                         return 0;
 319         case EF_FRV_GPR32:
 320         case 0:
 321                 break;
 322         default:
 323                 return 0;
 324         }
 325
 326         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 327         case EF_FRV_FPR64:
 328                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 329                         return 0;
 330         case EF_FRV_FPR32:
 331         case EF_FRV_FPR_NONE:
 332         case 0:
 333                 break;
 334         default:
 335                 return 0;
 336         }
 337
 338         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 339                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 340                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 341                         return 0;
 342
 343         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 344         case EF_FRV_CPU_GENERIC:
 345                 break;
 346         case EF_FRV_CPU_FR300:
 347         case EF_FRV_CPU_SIMPLE:
 348         case EF_FRV_CPU_TOMCAT:
 349         default:
 350                 return 0;
 351         case EF_FRV_CPU_FR400:
 352                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 353                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 354                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 355                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 356                         return 0;
 357                 break;
 358         case EF_FRV_CPU_FR450:
 359                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 360                         return 0;
 361                 break;
 362         case EF_FRV_CPU_FR500:
 363                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 364                         return 0;
 365                 break;
 366         case EF_FRV_CPU_FR550:
 367                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 368                         return 0;
 369                 break;
 370         }
 371
 372         return 1;
 373 }
 374
 375 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 376 {
 377         memcpy(fpregs,
 378                &current->thread.user->f,
 379                sizeof(current->thread.user->f));
 380         return 1;
 381 }