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 #include <linux/rcupdate.h>
  29
  30 #include <asm/asm-offsets.h>
  31 #include <asm/uaccess.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 asmlinkage void ret_from_kernel_thread(void);
  42
  43 #include <asm/pgalloc.h>
  44
  45 void (*pm_power_off)(void);
  46 EXPORT_SYMBOL(pm_power_off);
  47
  48 static void core_sleep_idle(void)
  49 {
  50 #ifdef LED_DEBUG_SLEEP
  51         /* Show that we're sleeping... */
  52         __set_LEDS(0x55aa);
  53 #endif
  54         frv_cpu_core_sleep();
  55 #ifdef LED_DEBUG_SLEEP
  56         /* ... and that we woke up */
  57         __set_LEDS(0);
  58 #endif
  59         mb();
  60 }
  61
  62 void (*idle)(void) = core_sleep_idle;
  63
  64 /*
  65  * The idle thread. There's no useful work to be
  66  * done, so just try to conserve power and have a
  67  * low exit latency (ie sit in a loop waiting for
  68  * somebody to say that they'd like to reschedule)
  69  */
  70 void cpu_idle(void)
  71 {
  72         /* endless idle loop with no priority at all */
  73         while (1) {
  74                 rcu_idle_enter();
  75                 while (!need_resched()) {
  76                         check_pgt_cache();
  77
  78                         if (!frv_dma_inprogress && idle)
  79                                 idle();
  80                 }
  81                 rcu_idle_exit();
  82
  83                 schedule_preempt_disabled();
  84         }
  85 }
  86
  87 void machine_restart(char * __unused)
  88 {
  89         unsigned long reset_addr;
  90 #ifdef CONFIG_GDBSTUB
  91         gdbstub_exit(0);
  92 #endif
  93
  94         if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
  95                 reset_addr = 0xfefff500;
  96         else
  97                 reset_addr = 0xfeff0500;
  98
  99         /* Software reset. */
 100         asm volatile("      dcef @(gr0,gr0),1 ! membar !"
 101                      "      sti     %1,@(%0,0) !"
 102                      "      nop ! nop ! nop ! nop ! nop ! "
 103                      "      nop ! nop ! nop ! nop ! nop ! "
 104                      "      nop ! nop ! nop ! nop ! nop ! "
 105                      "      nop ! nop ! nop ! nop ! nop ! "
 106                      : : "r" (reset_addr), "r" (1) );
 107
 108         for (;;)
 109                 ;
 110 }
 111
 112 void machine_halt(void)
 113 {
 114 #ifdef CONFIG_GDBSTUB
 115         gdbstub_exit(0);
 116 #endif
 117
 118         for (;;);
 119 }
 120
 121 void machine_power_off(void)
 122 {
 123 #ifdef CONFIG_GDBSTUB
 124         gdbstub_exit(0);
 125 #endif
 126
 127         for (;;);
 128 }
 129
 130 void flush_thread(void)
 131 {
 132         /* nothing */
 133 }
 134
 135 inline unsigned long user_stack(const struct pt_regs *regs)
 136 {
 137         while (regs->next_frame)
 138                 regs = regs->next_frame;
 139         return user_mode(regs) ? regs->sp : 0;
 140 }
 141
 142 asmlinkage int sys_fork(void)
 143 {
 144 #ifndef CONFIG_MMU
 145         /* fork almost works, enough to trick you into looking elsewhere:-( */
 146         return -EINVAL;
 147 #else
 148         return do_fork(SIGCHLD, user_stack(__frame), __frame, 0, NULL, NULL);
 149 #endif
 150 }
 151
 152 asmlinkage int sys_vfork(void)
 153 {
 154         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, user_stack(__frame), __frame, 0,
 155                        NULL, NULL);
 156 }
 157
 158 /*****************************************************************************/
 159 /*
 160  * clone a process
 161  * - tlsptr is retrieved by copy_thread()
 162  */
 163 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 164                          int __user *parent_tidptr, int __user *child_tidptr,
 165                          int __user *tlsptr)
 166 {
 167         if (!newsp)
 168                 newsp = user_stack(__frame);
 169         return do_fork(clone_flags, newsp, __frame, 0, parent_tidptr, child_tidptr);
 170 } /* end sys_clone() */
 171
 172 /*
 173  * set up the kernel stack and exception frames for a new process
 174  */
 175 int copy_thread(unsigned long clone_flags,
 176                 unsigned long usp, unsigned long arg,
 177                 struct task_struct *p, struct pt_regs *regs)
 178 {
 179         struct pt_regs *childregs;
 180
 181         childregs = (struct pt_regs *)
 182                 (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
 183
 184         p->set_child_tid = p->clear_child_tid = NULL;
 185
 186         p->thread.frame  = childregs;
 187         p->thread.curr   = p;
 188         p->thread.sp     = (unsigned long) childregs;
 189         p->thread.fp     = 0;
 190         p->thread.lr     = 0;
 191         p->thread.frame0 = childregs;
 192
 193         if (unlikely(!regs)) {
 194                 memset(childregs, 0, sizeof(struct pt_regs));
 195                 childregs->gr9 = usp; /* function */
 196                 childregs->gr8 = arg;
 197                 chilregs->psr = PSR_S;
 198                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 199                 save_user_regs(p->thread.user);
 200                 return 0;
 201         }
 202
 203         /* set up the userspace frame (the only place that the USP is stored) */
 204         *childregs = *regs;
 205
 206         childregs->sp           = usp;
 207         childregs->next_frame   = NULL;
 208
 209         p->thread.pc = (unsigned long) ret_from_fork;
 210
 211         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 212         if (clone_flags & CLONE_SETTLS)
 213                 childregs->gr29 = childregs->gr12;
 214
 215         save_user_regs(p->thread.user);
 216
 217         return 0;
 218 } /* end copy_thread() */
 219
 220 unsigned long get_wchan(struct task_struct *p)
 221 {
 222         struct pt_regs *regs0;
 223         unsigned long fp, pc;
 224         unsigned long stack_limit;
 225         int count = 0;
 226         if (!p || p == current || p->state == TASK_RUNNING)
 227                 return 0;
 228
 229         stack_limit = (unsigned long) (p + 1);
 230         fp = p->thread.fp;
 231         regs0 = p->thread.frame0;
 232
 233         do {
 234                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 235                         return 0;
 236
 237                 pc = ((unsigned long *) fp)[2];
 238
 239                 /* FIXME: This depends on the order of these functions. */
 240                 if (!in_sched_functions(pc))
 241                         return pc;
 242
 243                 fp = *(unsigned long *) fp;
 244         } while (count++ < 16);
 245
 246         return 0;
 247 }
 248
 249 unsigned long thread_saved_pc(struct task_struct *tsk)
 250 {
 251         /* Check whether the thread is blocked in resume() */
 252         if (in_sched_functions(tsk->thread.pc))
 253                 return ((unsigned long *)tsk->thread.fp)[2];
 254         else
 255                 return tsk->thread.pc;
 256 }
 257
 258 int elf_check_arch(const struct elf32_hdr *hdr)
 259 {
 260         unsigned long hsr0 = __get_HSR(0);
 261         unsigned long psr = __get_PSR();
 262
 263         if (hdr->e_machine != EM_FRV)
 264                 return 0;
 265
 266         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 267         case EF_FRV_GPR64:
 268                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 269                         return 0;
 270         case EF_FRV_GPR32:
 271         case 0:
 272                 break;
 273         default:
 274                 return 0;
 275         }
 276
 277         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 278         case EF_FRV_FPR64:
 279                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 280                         return 0;
 281         case EF_FRV_FPR32:
 282         case EF_FRV_FPR_NONE:
 283         case 0:
 284                 break;
 285         default:
 286                 return 0;
 287         }
 288
 289         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 290                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 291                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 292                         return 0;
 293
 294         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 295         case EF_FRV_CPU_GENERIC:
 296                 break;
 297         case EF_FRV_CPU_FR300:
 298         case EF_FRV_CPU_SIMPLE:
 299         case EF_FRV_CPU_TOMCAT:
 300         default:
 301                 return 0;
 302         case EF_FRV_CPU_FR400:
 303                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 304                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 305                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 306                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 307                         return 0;
 308                 break;
 309         case EF_FRV_CPU_FR450:
 310                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 311                         return 0;
 312                 break;
 313         case EF_FRV_CPU_FR500:
 314                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 315                         return 0;
 316                 break;
 317         case EF_FRV_CPU_FR550:
 318                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 319                         return 0;
 320                 break;
 321         }
 322
 323         return 1;
 324 }
 325
 326 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 327 {
 328         memcpy(fpregs,
 329                &current->thread.user->f,
 330                sizeof(current->thread.user->f));
 331         return 1;
 332 }