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/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 #include <linux/pagemap.h>
  28
  29 #include <asm/asm-offsets.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/system.h>
  32 #include <asm/setup.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/tlb.h>
  35 #include <asm/gdb-stub.h>
  36 #include <asm/mb-regs.h>
  37
  38 #include "local.h"
  39
  40 asmlinkage void ret_from_fork(void);
  41
  42 #include <asm/pgalloc.h>
  43
  44 void (*pm_power_off)(void);
  45 EXPORT_SYMBOL(pm_power_off);
  46
  47 struct task_struct *alloc_task_struct_node(int node)
  48 {
  49         struct task_struct *p = kmalloc_node(THREAD_SIZE, GFP_KERNEL, node);
  50
  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                 schedule_preempt_disabled();
  96         }
  97 }
  98
  99 void machine_restart(char * __unused)
 100 {
 101         unsigned long reset_addr;
 102 #ifdef CONFIG_GDBSTUB
 103         gdbstub_exit(0);
 104 #endif
 105
 106         if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
 107                 reset_addr = 0xfefff500;
 108         else
 109                 reset_addr = 0xfeff0500;
 110
 111         /* Software reset. */
 112         asm volatile("      dcef @(gr0,gr0),1 ! membar !"
 113                      "      sti     %1,@(%0,0) !"
 114                      "      nop ! nop ! nop ! nop ! nop ! "
 115                      "      nop ! nop ! nop ! nop ! nop ! "
 116                      "      nop ! nop ! nop ! nop ! nop ! "
 117                      "      nop ! nop ! nop ! nop ! nop ! "
 118                      : : "r" (reset_addr), "r" (1) );
 119
 120         for (;;)
 121                 ;
 122 }
 123
 124 void machine_halt(void)
 125 {
 126 #ifdef CONFIG_GDBSTUB
 127         gdbstub_exit(0);
 128 #endif
 129
 130         for (;;);
 131 }
 132
 133 void machine_power_off(void)
 134 {
 135 #ifdef CONFIG_GDBSTUB
 136         gdbstub_exit(0);
 137 #endif
 138
 139         for (;;);
 140 }
 141
 142 void flush_thread(void)
 143 {
 144         /* nothing */
 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(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 - FRV_FRAME0_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(const char __user *name,
 249                           const char __user *const __user *argv,
 250                           const char __user *const __user *envp)
 251 {
 252         int error;
 253         char * filename;
 254
 255         filename = getname(name);
 256         error = PTR_ERR(filename);
 257         if (IS_ERR(filename))
 258                 return error;
 259         error = do_execve(filename, argv, envp, __frame);
 260         putname(filename);
 261         return error;
 262 }
 263
 264 unsigned long get_wchan(struct task_struct *p)
 265 {
 266         struct pt_regs *regs0;
 267         unsigned long fp, pc;
 268         unsigned long stack_limit;
 269         int count = 0;
 270         if (!p || p == current || p->state == TASK_RUNNING)
 271                 return 0;
 272
 273         stack_limit = (unsigned long) (p + 1);
 274         fp = p->thread.fp;
 275         regs0 = p->thread.frame0;
 276
 277         do {
 278                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 279                         return 0;
 280
 281                 pc = ((unsigned long *) fp)[2];
 282
 283                 /* FIXME: This depends on the order of these functions. */
 284                 if (!in_sched_functions(pc))
 285                         return pc;
 286
 287                 fp = *(unsigned long *) fp;
 288         } while (count++ < 16);
 289
 290         return 0;
 291 }
 292
 293 unsigned long thread_saved_pc(struct task_struct *tsk)
 294 {
 295         /* Check whether the thread is blocked in resume() */
 296         if (in_sched_functions(tsk->thread.pc))
 297                 return ((unsigned long *)tsk->thread.fp)[2];
 298         else
 299                 return tsk->thread.pc;
 300 }
 301
 302 int elf_check_arch(const struct elf32_hdr *hdr)
 303 {
 304         unsigned long hsr0 = __get_HSR(0);
 305         unsigned long psr = __get_PSR();
 306
 307         if (hdr->e_machine != EM_FRV)
 308                 return 0;
 309
 310         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 311         case EF_FRV_GPR64:
 312                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 313                         return 0;
 314         case EF_FRV_GPR32:
 315         case 0:
 316                 break;
 317         default:
 318                 return 0;
 319         }
 320
 321         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 322         case EF_FRV_FPR64:
 323                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 324                         return 0;
 325         case EF_FRV_FPR32:
 326         case EF_FRV_FPR_NONE:
 327         case 0:
 328                 break;
 329         default:
 330                 return 0;
 331         }
 332
 333         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 334                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 335                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 336                         return 0;
 337
 338         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 339         case EF_FRV_CPU_GENERIC:
 340                 break;
 341         case EF_FRV_CPU_FR300:
 342         case EF_FRV_CPU_SIMPLE:
 343         case EF_FRV_CPU_TOMCAT:
 344         default:
 345                 return 0;
 346         case EF_FRV_CPU_FR400:
 347                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 348                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 349                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 350                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 351                         return 0;
 352                 break;
 353         case EF_FRV_CPU_FR450:
 354                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 355                         return 0;
 356                 break;
 357         case EF_FRV_CPU_FR500:
 358                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 359                         return 0;
 360                 break;
 361         case EF_FRV_CPU_FR550:
 362                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 363                         return 0;
 364                 break;
 365         }
 366
 367         return 1;
 368 }
 369
 370 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 371 {
 372         memcpy(fpregs,
 373                &current->thread.user->f,
 374                sizeof(current->thread.user->f));
 375         return 1;
 376 }