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