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 /*
 143  * set up the kernel stack and exception frames for a new process
 144  */
 145 int copy_thread(unsigned long clone_flags,
 146                 unsigned long usp, unsigned long arg,
 147                 struct task_struct *p)
 148 {
 149         struct pt_regs *childregs;
 150
 151         childregs = (struct pt_regs *)
 152                 (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
 153
 154         /* set up the userspace frame (the only place that the USP is stored) */
 155         *childregs = *current_pt_regs();
 156
 157         p->thread.frame  = childregs;
 158         p->thread.curr   = p;
 159         p->thread.sp     = (unsigned long) childregs;
 160         p->thread.fp     = 0;
 161         p->thread.lr     = 0;
 162         p->thread.frame0 = childregs;
 163
 164         if (unlikely(p->flags & PF_KTHREAD)) {
 165                 childregs->gr9 = usp; /* function */
 166                 childregs->gr8 = arg;
 167                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 168                 save_user_regs(p->thread.user);
 169                 return 0;
 170         }
 171         if (usp)
 172                 childregs->sp = usp;
 173         childregs->next_frame   = NULL;
 174
 175         p->thread.pc = (unsigned long) ret_from_fork;
 176
 177         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 178         if (clone_flags & CLONE_SETTLS)
 179                 childregs->gr29 = childregs->gr12;
 180
 181         save_user_regs(p->thread.user);
 182
 183         return 0;
 184 } /* end copy_thread() */
 185
 186 unsigned long get_wchan(struct task_struct *p)
 187 {
 188         struct pt_regs *regs0;
 189         unsigned long fp, pc;
 190         unsigned long stack_limit;
 191         int count = 0;
 192         if (!p || p == current || p->state == TASK_RUNNING)
 193                 return 0;
 194
 195         stack_limit = (unsigned long) (p + 1);
 196         fp = p->thread.fp;
 197         regs0 = p->thread.frame0;
 198
 199         do {
 200                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 201                         return 0;
 202
 203                 pc = ((unsigned long *) fp)[2];
 204
 205                 /* FIXME: This depends on the order of these functions. */
 206                 if (!in_sched_functions(pc))
 207                         return pc;
 208
 209                 fp = *(unsigned long *) fp;
 210         } while (count++ < 16);
 211
 212         return 0;
 213 }
 214
 215 unsigned long thread_saved_pc(struct task_struct *tsk)
 216 {
 217         /* Check whether the thread is blocked in resume() */
 218         if (in_sched_functions(tsk->thread.pc))
 219                 return ((unsigned long *)tsk->thread.fp)[2];
 220         else
 221                 return tsk->thread.pc;
 222 }
 223
 224 int elf_check_arch(const struct elf32_hdr *hdr)
 225 {
 226         unsigned long hsr0 = __get_HSR(0);
 227         unsigned long psr = __get_PSR();
 228
 229         if (hdr->e_machine != EM_FRV)
 230                 return 0;
 231
 232         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 233         case EF_FRV_GPR64:
 234                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 235                         return 0;
 236         case EF_FRV_GPR32:
 237         case 0:
 238                 break;
 239         default:
 240                 return 0;
 241         }
 242
 243         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 244         case EF_FRV_FPR64:
 245                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 246                         return 0;
 247         case EF_FRV_FPR32:
 248         case EF_FRV_FPR_NONE:
 249         case 0:
 250                 break;
 251         default:
 252                 return 0;
 253         }
 254
 255         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 256                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 257                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 258                         return 0;
 259
 260         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 261         case EF_FRV_CPU_GENERIC:
 262                 break;
 263         case EF_FRV_CPU_FR300:
 264         case EF_FRV_CPU_SIMPLE:
 265         case EF_FRV_CPU_TOMCAT:
 266         default:
 267                 return 0;
 268         case EF_FRV_CPU_FR400:
 269                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 270                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 271                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 272                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 273                         return 0;
 274                 break;
 275         case EF_FRV_CPU_FR450:
 276                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 277                         return 0;
 278                 break;
 279         case EF_FRV_CPU_FR500:
 280                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 281                         return 0;
 282                 break;
 283         case EF_FRV_CPU_FR550:
 284                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 285                         return 0;
 286                 break;
 287         }
 288
 289         return 1;
 290 }
 291
 292 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 293 {
 294         memcpy(fpregs,
 295                &current->thread.user->f,
 296                sizeof(current->thread.user->f));
 297         return 1;
 298 }