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/sched/debug.h>
  17 #include <linux/sched/task.h>
  18 #include <linux/sched/task_stack.h>
  19 #include <linux/kernel.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/stddef.h>
  23 #include <linux/unistd.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/slab.h>
  26 #include <linux/user.h>
  27 #include <linux/elf.h>
  28 #include <linux/reboot.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/rcupdate.h>
  32
  33 #include <asm/asm-offsets.h>
  34 #include <linux/uaccess.h>
  35 #include <asm/setup.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/tlb.h>
  38 #include <asm/gdb-stub.h>
  39 #include <asm/mb-regs.h>
  40
  41 #include "local.h"
  42
  43 asmlinkage void ret_from_fork(void);
  44 asmlinkage void ret_from_kernel_thread(void);
  45
  46 #include <asm/pgalloc.h>
  47
  48 void (*pm_power_off)(void);
  49 EXPORT_SYMBOL(pm_power_off);
  50
  51 static void core_sleep_idle(void)
  52 {
  53 #ifdef LED_DEBUG_SLEEP
  54         /* Show that we're sleeping... */
  55         __set_LEDS(0x55aa);
  56 #endif
  57         frv_cpu_core_sleep();
  58 #ifdef LED_DEBUG_SLEEP
  59         /* ... and that we woke up */
  60         __set_LEDS(0);
  61 #endif
  62         mb();
  63 }
  64
  65 void arch_cpu_idle(void)
  66 {
  67         if (!frv_dma_inprogress)
  68                 core_sleep_idle();
  69         else
  70                 local_irq_enable();
  71 }
  72
  73 void machine_restart(char * __unused)
  74 {
  75         unsigned long reset_addr;
  76 #ifdef CONFIG_GDBSTUB
  77         gdbstub_exit(0);
  78 #endif
  79
  80         if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
  81                 reset_addr = 0xfefff500;
  82         else
  83                 reset_addr = 0xfeff0500;
  84
  85         /* Software reset. */
  86         asm volatile("      dcef @(gr0,gr0),1 ! membar !"
  87                      "      sti     %1,@(%0,0) !"
  88                      "      nop ! nop ! nop ! nop ! nop ! "
  89                      "      nop ! nop ! nop ! nop ! nop ! "
  90                      "      nop ! nop ! nop ! nop ! nop ! "
  91                      "      nop ! nop ! nop ! nop ! nop ! "
  92                      : : "r" (reset_addr), "r" (1) );
  93
  94         for (;;)
  95                 ;
  96 }
  97
  98 void machine_halt(void)
  99 {
 100 #ifdef CONFIG_GDBSTUB
 101         gdbstub_exit(0);
 102 #endif
 103
 104         for (;;);
 105 }
 106
 107 void machine_power_off(void)
 108 {
 109 #ifdef CONFIG_GDBSTUB
 110         gdbstub_exit(0);
 111 #endif
 112
 113         for (;;);
 114 }
 115
 116 void flush_thread(void)
 117 {
 118         /* nothing */
 119 }
 120
 121 inline unsigned long user_stack(const struct pt_regs *regs)
 122 {
 123         while (regs->next_frame)
 124                 regs = regs->next_frame;
 125         return user_mode(regs) ? regs->sp : 0;
 126 }
 127
 128 /*
 129  * set up the kernel stack and exception frames for a new process
 130  */
 131 int copy_thread(unsigned long clone_flags,
 132                 unsigned long usp, unsigned long arg,
 133                 struct task_struct *p)
 134 {
 135         struct pt_regs *childregs;
 136
 137         childregs = (struct pt_regs *)
 138                 (task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
 139
 140         /* set up the userspace frame (the only place that the USP is stored) */
 141         *childregs = *current_pt_regs();
 142
 143         p->thread.frame  = childregs;
 144         p->thread.curr   = p;
 145         p->thread.sp     = (unsigned long) childregs;
 146         p->thread.fp     = 0;
 147         p->thread.lr     = 0;
 148         p->thread.frame0 = childregs;
 149
 150         if (unlikely(p->flags & PF_KTHREAD)) {
 151                 childregs->gr9 = usp; /* function */
 152                 childregs->gr8 = arg;
 153                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 154                 save_user_regs(p->thread.user);
 155                 return 0;
 156         }
 157         if (usp)
 158                 childregs->sp = usp;
 159         childregs->next_frame   = NULL;
 160
 161         p->thread.pc = (unsigned long) ret_from_fork;
 162
 163         /* the new TLS pointer is passed in as arg #5 to sys_clone() */
 164         if (clone_flags & CLONE_SETTLS)
 165                 childregs->gr29 = childregs->gr12;
 166
 167         save_user_regs(p->thread.user);
 168
 169         return 0;
 170 } /* end copy_thread() */
 171
 172 unsigned long get_wchan(struct task_struct *p)
 173 {
 174         struct pt_regs *regs0;
 175         unsigned long fp, pc;
 176         unsigned long stack_limit;
 177         int count = 0;
 178         if (!p || p == current || p->state == TASK_RUNNING)
 179                 return 0;
 180
 181         stack_limit = (unsigned long) (p + 1);
 182         fp = p->thread.fp;
 183         regs0 = p->thread.frame0;
 184
 185         do {
 186                 if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
 187                         return 0;
 188
 189                 pc = ((unsigned long *) fp)[2];
 190
 191                 /* FIXME: This depends on the order of these functions. */
 192                 if (!in_sched_functions(pc))
 193                         return pc;
 194
 195                 fp = *(unsigned long *) fp;
 196         } while (count++ < 16);
 197
 198         return 0;
 199 }
 200
 201 unsigned long thread_saved_pc(struct task_struct *tsk)
 202 {
 203         /* Check whether the thread is blocked in resume() */
 204         if (in_sched_functions(tsk->thread.pc))
 205                 return ((unsigned long *)tsk->thread.fp)[2];
 206         else
 207                 return tsk->thread.pc;
 208 }
 209
 210 int elf_check_arch(const struct elf32_hdr *hdr)
 211 {
 212         unsigned long hsr0 = __get_HSR(0);
 213         unsigned long psr = __get_PSR();
 214
 215         if (hdr->e_machine != EM_FRV)
 216                 return 0;
 217
 218         switch (hdr->e_flags & EF_FRV_GPR_MASK) {
 219         case EF_FRV_GPR64:
 220                 if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
 221                         return 0;
 222         case EF_FRV_GPR32:
 223         case 0:
 224                 break;
 225         default:
 226                 return 0;
 227         }
 228
 229         switch (hdr->e_flags & EF_FRV_FPR_MASK) {
 230         case EF_FRV_FPR64:
 231                 if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
 232                         return 0;
 233         case EF_FRV_FPR32:
 234         case EF_FRV_FPR_NONE:
 235         case 0:
 236                 break;
 237         default:
 238                 return 0;
 239         }
 240
 241         if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
 242                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 243                     PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 244                         return 0;
 245
 246         switch (hdr->e_flags & EF_FRV_CPU_MASK) {
 247         case EF_FRV_CPU_GENERIC:
 248                 break;
 249         case EF_FRV_CPU_FR300:
 250         case EF_FRV_CPU_SIMPLE:
 251         case EF_FRV_CPU_TOMCAT:
 252         default:
 253                 return 0;
 254         case EF_FRV_CPU_FR400:
 255                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
 256                     PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
 257                     PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
 258                     PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 259                         return 0;
 260                 break;
 261         case EF_FRV_CPU_FR450:
 262                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
 263                         return 0;
 264                 break;
 265         case EF_FRV_CPU_FR500:
 266                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
 267                         return 0;
 268                 break;
 269         case EF_FRV_CPU_FR550:
 270                 if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
 271                         return 0;
 272                 break;
 273         }
 274
 275         return 1;
 276 }
 277
 278 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
 279 {
 280         memcpy(fpregs,
 281                &current->thread.user->f,
 282                sizeof(current->thread.user->f));
 283         return 1;
 284 }