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 #include <linux/pagemap.h>
  29
  30 #include <asm/asm-offsets.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <asm/setup.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/tlb.h>
  36 #include <asm/gdb-stub.h>
  37 #include <asm/mb-regs.h>
  38
  39 #include "local.h"
  40
  41 asmlinkage void ret_from_fork(void);
  42
  43 #include <asm/pgalloc.h>
  44
  45 void (*pm_power_off)(void);
  46 EXPORT_SYMBOL(pm_power_off);
  47
  48 struct task_struct *alloc_task_struct(void)
  49 {
  50         struct task_struct *p = kmalloc(THREAD_SIZE, GFP_KERNEL);
  51         if (p)
  52                 atomic_set((atomic_t *)(p+1), 1);
  53         return p;
  54 }
  55
  56 void free_task_struct(struct task_struct *p)
  57 {
  58         if (atomic_dec_and_test((atomic_t *)(p+1)))
  59                 kfree(p);
  60 }
  61
  62 static void core_sleep_idle(void)
  63 {
  64 #ifdef LED_DEBUG_SLEEP
  65         /* Show that we're sleeping... */
  66         __set_LEDS(0x55aa);
  67 #endif
  68         frv_cpu_core_sleep();
  69 #ifdef LED_DEBUG_SLEEP
  70         /* ... and that we woke up */
  71         __set_LEDS(0);
  72 #endif
  73         mb();
  74 }
  75
  76 void (*idle)(void) = core_sleep_idle;
  77
  78 /*
  79  * The idle thread. There's no useful work to be
  80  * done, so just try to conserve power and have a
  81  * low exit latency (ie sit in a loop waiting for
  82  * somebody to say that they'd like to reschedule)
  83  */
  84 void cpu_idle(void)
  85 {
  86         int cpu = smp_processor_id();
  87
  88         /* endless idle loop with no priority at all */
  89         while (1) {
  90                 while (!need_resched()) {
  91                         irq_stat[cpu].idle_timestamp = jiffies;
  92
  93                         check_pgt_cache();
  94
  95                         if (!frv_dma_inprogress && idle)
  96                                 idle();
  97                 }
  98
  99                 preempt_enable_no_resched();
 100                 schedule();
 101                 preempt_disable();
 102         }
 103 }
 104
 105 void machine_restart(char * __unused)
 106 {
 107         unsigned long reset_addr;
 108 #ifdef CONFIG_GDBSTUB
 109         gdbstub_exit(0);
 110 #endif
 111
 112         if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
 113                 reset_addr = 0xfefff500;
 114         else
 115                 reset_addr = 0xfeff0500;
 116
 117         /* Software reset. */
 118         asm volatile("      dcef @(gr0,gr0),1 ! membar !"
 119                      "      sti     %1,@(%0,0) !"
 120                      "      nop ! nop ! nop ! nop ! nop ! "
 121                      "      nop ! nop ! nop ! nop ! nop ! "
 122                      "      nop ! nop ! nop ! nop ! nop ! "
 123                      "      nop ! nop ! nop ! nop ! nop ! "
 124                      : : "r" (reset_addr), "r" (1) );
 125
 126         for (;;)
 127                 ;
 128 }
 129
 130 void machine_halt(void)
 131 {
 132 #ifdef CONFIG_GDBSTUB
 133         gdbstub_exit(0);
 134 #endif
 135
 136         for (;;);
 137 }
 138
 139 void machine_power_off(void)
 140 {
 141 #ifdef CONFIG_GDBSTUB
 142         gdbstub_exit(0);
 143 #endif
 144
 145         for (;;);
 146 }
 147
 148 void flush_thread(void)
 149 {
 150 #if 0 //ndef NO_FPU
 151         unsigned long zero = 0;
 152 #endif
 153         set_fs(USER_DS);
 154 }
 155
 156 inline unsigned long user_stack(const struct pt_regs *regs)
 157 {
 158         while (regs->next_frame)
 159                 regs = regs->next_frame;
 160         return user_mode(regs) ? regs->sp : 0;
 161 }
 162
 163 asmlinkage int sys_fork(void)
 164 {
 165 #ifndef CONFIG_MMU
 166         /* fork almost works, enough to trick you into looking elsewhere:-( */
 167         return -EINVAL;
 168 #else
 169         return do_fork(SIGCHLD, user_stack(__frame), __frame, 0, NULL, NULL);
 170 #endif
 171 }
 172
 173 asmlinkage int sys_vfork(void)
 174 {
 175         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, user_stack(__frame), __frame, 0,
 176                        NULL, NULL);
 177 }
 178
 179 /*****************************************************************************/
 180 /*
 181  * clone a process
 182  * - tlsptr is retrieved by copy_thread()
 183  */
 184 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 185                          int __user *parent_tidptr, int __user *child_tidptr,
 186                          int __user *tlsptr)
 187 {
 188         if (!newsp)
 189                 newsp = user_stack(__frame);
 190         return do_fork(clone_flags, newsp, __frame, 0, parent_tidptr, child_tidptr);
 191 } /* end sys_clone() */
 192
 193 /*****************************************************************************/
 194 /*
 195  * This gets called before we allocate a new thread and copy
 196  * the current task into it.
 197  */
 198 void prepare_to_copy(struct task_struct *tsk)
 199 {
 200         //unlazy_fpu(tsk);
 201 } /* end prepare_to_copy() */
 202
 203 /*****************************************************************************/
 204 /*
 205  * set up the kernel stack and exception frames for a new process
 206  */
 207 int copy_thread(unsigned long clone_flags,
 208                 unsigned long usp, unsigned long topstk,
 209                 struct task_struct *p, struct pt_regs *regs)
 210 {
 211         struct pt_regs *childregs0, *childregs, *regs0;
 212
 213         regs0 = __kernel_frame0_ptr;
 214         childregs0 = (struct pt_regs *)
 215                 (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
 216         childregs = childregs0;
 217
 218         /* set up the userspace frame (the only place that the USP is stored) */
 219         *childregs0 = *regs0;
 220
 221         childregs0->gr8         = 0;
 222         childregs0->sp          = usp;
 223         childregs0->next_frame  = NULL;
 224
 225         /* set up the return kernel frame if called from kernel_thread() */
 226         if (regs != regs0) {
 227                 childregs--;
 228                 *childregs = *regs;
 229                 childregs->sp = (unsigned long) childregs0;
 230                 childregs->next_frame = childregs0;
 231                 childregs->gr15 = (unsigned long) task_thread_info(p);
 232                 childregs->gr29 = (unsigned long) p;
 233         }
 234
 235         p->set_child_tid = p->clear_child_tid = NULL;
 236
 237         p->thread.frame  = childregs;
 238         p->thread.curr   = p;
 239         p->thread.sp     = (unsigned long) childregs;
 240         p->thread.fp     = 0;
 241         p->thread.lr     = 0;
 242         p->thread.pc     = (unsigned long) ret_from_fork;
 243         p->thread.frame0 = childregs0;
 244
 245         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 246         if (clone_flags & CLONE_SETTLS)
 247                 childregs->gr29 = childregs->gr12;
 248
 249         save_user_regs(p->thread.user);
 250
 251         return 0;
 252 } /* end copy_thread() */
 253
 254 /*
 255  * sys_execve() executes a new program.
 256  */
 257 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 258 {
 259         int error;
 260         char * filename;
 261
 262         lock_kernel();
 263         filename = getname(name);
 264         error = PTR_ERR(filename);
 265         if (IS_ERR(filename))
 266                 goto out;
 267         error = do_execve(filename, argv, envp, __frame);
 268         putname(filename);
 269  out:
 270         unlock_kernel();
 271         return error;
 272 }
 273
 274 unsigned long get_wchan(struct task_struct *p)
 275 {
 276         struct pt_regs *regs0;
 277         unsigned long fp, pc;
 278         unsigned long stack_limit;
 279         int count = 0;
 280         if (!p || p == current || p->state == TASK_RUNNING)
 281                 return 0;
 282
 283         stack_limit = (unsigned long) (p + 1);
 284         fp = p->thread.fp;
 285         regs0 = p->thread.frame0;
 286
 287         do {
 288                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 289                         return 0;
 290
 291                 pc = ((unsigned long *) fp)[2];
 292
 293                 /* FIXME: This depends on the order of these functions. */
 294                 if (!in_sched_functions(pc))
 295                         return pc;
 296
 297                 fp = *(unsigned long *) fp;
 298         } while (count++ < 16);
 299
 300         return 0;
 301 }
 302
 303 unsigned long thread_saved_pc(struct task_struct *tsk)
 304 {
 305         /* Check whether the thread is blocked in resume() */
 306         if (in_sched_functions(tsk->thread.pc))
 307                 return ((unsigned long *)tsk->thread.fp)[2];
 308         else
 309                 return tsk->thread.pc;
 310 }
 311
 312 int elf_check_arch(const struct elf32_hdr *hdr)
 313 {
 314         unsigned long hsr0 = __get_HSR(0);
 315         unsigned long psr = __get_PSR();
 316
 317         if (hdr->e_machine != EM_FRV)
 318                 return 0;
 319
 320         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 321         case EF_FRV_GPR64:
 322                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 323                         return 0;
 324         case EF_FRV_GPR32:
 325         case 0:
 326                 break;
 327         default:
 328                 return 0;
 329         }
 330
 331         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 332         case EF_FRV_FPR64:
 333                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 334                         return 0;
 335         case EF_FRV_FPR32:
 336         case EF_FRV_FPR_NONE:
 337         case 0:
 338                 break;
 339         default:
 340                 return 0;
 341         }
 342
 343         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 344                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 345                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 346                         return 0;
 347
 348         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 349         case EF_FRV_CPU_GENERIC:
 350                 break;
 351         case EF_FRV_CPU_FR300:
 352         case EF_FRV_CPU_SIMPLE:
 353         case EF_FRV_CPU_TOMCAT:
 354         default:
 355                 return 0;
 356         case EF_FRV_CPU_FR400:
 357                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 358                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 359                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 360                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 361                         return 0;
 362                 break;
 363         case EF_FRV_CPU_FR450:
 364                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 365                         return 0;
 366                 break;
 367         case EF_FRV_CPU_FR500:
 368                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 369                         return 0;
 370                 break;
 371         case EF_FRV_CPU_FR550:
 372                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 373                         return 0;
 374                 break;
 375         }
 376
 377         return 1;
 378 }
 379
 380 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 381 {
 382         memcpy(fpregs,
 383                &current->thread.user->f,
 384                sizeof(current->thread.user->f));
 385         return 1;
 386 }