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