arch/parisc/kernel/process.c

   1 /*
   2  *    PARISC Architecture-dependent parts of process handling
   3  *    based on the work for i386
   4  *
   5  *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   6  *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   7  *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   8  *    Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
   9  *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
  10  *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
  11  *    Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
  12  *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
  13  *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
  14  *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
  15  *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
  16  *    Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>
  17  *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
  18  *
  19  *
  20  *    This program is free software; you can redistribute it and/or modify
  21  *    it under the terms of the GNU General Public License as published by
  22  *    the Free Software Foundation; either version 2 of the License, or
  23  *    (at your option) any later version.
  24  *
  25  *    This program is distributed in the hope that it will be useful,
  26  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *    GNU General Public License for more details.
  29  *
  30  *    You should have received a copy of the GNU General Public License
  31  *    along with this program; if not, write to the Free Software
  32  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  33  */
  34
  35 #include <stdarg.h>
  36
  37 #include <linux/elf.h>
  38 #include <linux/errno.h>
  39 #include <linux/kernel.h>
  40 #include <linux/mm.h>
  41 #include <linux/fs.h>
  42 #include <linux/module.h>
  43 #include <linux/personality.h>
  44 #include <linux/ptrace.h>
  45 #include <linux/sched.h>
  46 #include <linux/slab.h>
  47 #include <linux/stddef.h>
  48 #include <linux/unistd.h>
  49 #include <linux/kallsyms.h>
  50 #include <linux/uaccess.h>
  51 #include <linux/rcupdate.h>
  52
  53 #include <asm/io.h>
  54 #include <asm/asm-offsets.h>
  55 #include <asm/assembly.h>
  56 #include <asm/pdc.h>
  57 #include <asm/pdc_chassis.h>
  58 #include <asm/pgalloc.h>
  59 #include <asm/unwind.h>
  60 #include <asm/sections.h>
  61
  62 /*
  63  * The idle thread. There's no useful work to be
  64  * done, so just try to conserve power and have a
  65  * low exit latency (ie sit in a loop waiting for
  66  * somebody to say that they'd like to reschedule)
  67  */
  68 void cpu_idle(void)
  69 {
  70         set_thread_flag(TIF_POLLING_NRFLAG);
  71
  72         /* endless idle loop with no priority at all */
  73         while (1) {
  74                 rcu_idle_enter();
  75                 while (!need_resched())
  76                         barrier();
  77                 rcu_idle_exit();
  78                 schedule_preempt_disabled();
  79                 check_pgt_cache();
  80         }
  81 }
  82
  83
  84 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  85 #define CMD_RESET       5       /* reset any module */
  86
  87 /*
  88 ** The Wright Brothers and Gecko systems have a H/W problem
  89 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  90 ** the system. An HVERSION dependent PDC call was developed
  91 ** to perform a "safe", platform specific broadcast reset instead
  92 ** of kludging up all the code.
  93 **
  94 ** Older machines which do not implement PDC_BROADCAST_RESET will
  95 ** return (with an error) and the regular broadcast reset can be
  96 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  97 ** the PDC call will not return (the system will be reset).
  98 */
  99 void machine_restart(char *cmd)
 100 {
 101 #ifdef FASTBOOT_SELFTEST_SUPPORT
 102         /*
 103          ** If user has modified the Firmware Selftest Bitmap,
 104          ** run the tests specified in the bitmap after the
 105          ** system is rebooted w/PDC_DO_RESET.
 106          **
 107          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
 108          **
 109          ** Using "directed resets" at each processor with the MEM_TOC
 110          ** vector cleared will also avoid running destructive
 111          ** memory self tests. (Not implemented yet)
 112          */
 113         if (ftc_bitmap) {
 114                 pdc_do_firm_test_reset(ftc_bitmap);
 115         }
 116 #endif
 117         /* set up a new led state on systems shipped with a LED State panel */
 118         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 119
 120         /* "Normal" system reset */
 121         pdc_do_reset();
 122
 123         /* Nope...box should reset with just CMD_RESET now */
 124         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 125
 126         /* Wait for RESET to lay us to rest. */
 127         while (1) ;
 128
 129 }
 130
 131 void machine_halt(void)
 132 {
 133         /*
 134         ** The LED/ChassisCodes are updated by the led_halt()
 135         ** function, called by the reboot notifier chain.
 136         */
 137 }
 138
 139 void (*chassis_power_off)(void);
 140
 141 /*
 142  * This routine is called from sys_reboot to actually turn off the
 143  * machine
 144  */
 145 void machine_power_off(void)
 146 {
 147         /* If there is a registered power off handler, call it. */
 148         if (chassis_power_off)
 149                 chassis_power_off();
 150
 151         /* Put the soft power button back under hardware control.
 152          * If the user had already pressed the power button, the
 153          * following call will immediately power off. */
 154         pdc_soft_power_button(0);
 155
 156         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 157
 158         /* It seems we have no way to power the system off via
 159          * software. The user has to press the button himself. */
 160
 161         printk(KERN_EMERG "System shut down completed.\n"
 162                "Please power this system off now.");
 163 }
 164
 165 void (*pm_power_off)(void) = machine_power_off;
 166 EXPORT_SYMBOL(pm_power_off);
 167
 168 /*
 169  * Free current thread data structures etc..
 170  */
 171 void exit_thread(void)
 172 {
 173 }
 174
 175 void flush_thread(void)
 176 {
 177         /* Only needs to handle fpu stuff or perf monitors.
 178         ** REVISIT: several arches implement a "lazy fpu state".
 179         */
 180 }
 181
 182 void release_thread(struct task_struct *dead_task)
 183 {
 184 }
 185
 186 /*
 187  * Fill in the FPU structure for a core dump.
 188  */
 189
 190 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 191 {
 192         if (regs == NULL)
 193                 return 0;
 194
 195         memcpy(r, regs->fr, sizeof *r);
 196         return 1;
 197 }
 198
 199 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 200 {
 201         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 202         return 1;
 203 }
 204
 205 int
 206 copy_thread(unsigned long clone_flags, unsigned long usp,
 207             unsigned long arg, struct task_struct *p)
 208 {
 209         struct pt_regs *cregs = &(p->thread.regs);
 210         void *stack = task_stack_page(p);
 211
 212         /* We have to use void * instead of a function pointer, because
 213          * function pointers aren't a pointer to the function on 64-bit.
 214          * Make them const so the compiler knows they live in .text */
 215         extern void * const ret_from_kernel_thread;
 216         extern void * const child_return;
 217 #ifdef CONFIG_HPUX
 218         extern void * const hpux_child_return;
 219 #endif
 220         if (unlikely(p->flags & PF_KTHREAD)) {
 221                 memset(cregs, 0, sizeof(struct pt_regs));
 222                 if (!usp) /* idle thread */
 223                         return 0;
 224
 225                 /* kernel thread */
 226                 /* Must exit via ret_from_kernel_thread in order
 227                  * to call schedule_tail()
 228                  */
 229                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 230                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 231                 /*
 232                  * Copy function and argument to be called from
 233                  * ret_from_kernel_thread.
 234                  */
 235 #ifdef CONFIG_64BIT
 236                 cregs->gr[27] = ((unsigned long *)usp)[3];
 237                 cregs->gr[26] = ((unsigned long *)usp)[2];
 238 #else
 239                 cregs->gr[26] = usp;
 240 #endif
 241                 cregs->gr[25] = arg;
 242         } else {
 243                 /* user thread */
 244                 /* usp must be word aligned.  This also prevents users from
 245                  * passing in the value 1 (which is the signal for a special
 246                  * return for a kernel thread) */
 247                 if (usp) {
 248                         usp = ALIGN(usp, 4);
 249                         if (likely(usp))
 250                                 cregs->gr[30] = usp;
 251                 }
 252                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 253                 if (personality(p->personality) == PER_HPUX) {
 254 #ifdef CONFIG_HPUX
 255                         cregs->kpc = (unsigned long) &hpux_child_return;
 256 #else
 257                         BUG();
 258 #endif
 259                 } else {
 260                         cregs->kpc = (unsigned long) &child_return;
 261                 }
 262                 /* Setup thread TLS area from the 4th parameter in clone */
 263                 if (clone_flags & CLONE_SETTLS)
 264                         cregs->cr27 = cregs->gr[23];
 265         }
 266
 267         return 0;
 268 }
 269
 270 unsigned long thread_saved_pc(struct task_struct *t)
 271 {
 272         return t->thread.regs.kpc;
 273 }
 274
 275 unsigned long
 276 get_wchan(struct task_struct *p)
 277 {
 278         struct unwind_frame_info info;
 279         unsigned long ip;
 280         int count = 0;
 281
 282         if (!p || p == current || p->state == TASK_RUNNING)
 283                 return 0;
 284
 285         /*
 286          * These bracket the sleeping functions..
 287          */
 288
 289         unwind_frame_init_from_blocked_task(&info, p);
 290         do {
 291                 if (unwind_once(&info) < 0)
 292                         return 0;
 293                 ip = info.ip;
 294                 if (!in_sched_functions(ip))
 295                         return ip;
 296         } while (count++ < 16);
 297         return 0;
 298 }
 299
 300 #ifdef CONFIG_64BIT
 301 void *dereference_function_descriptor(void *ptr)
 302 {
 303         Elf64_Fdesc *desc = ptr;
 304         void *p;
 305
 306         if (!probe_kernel_address(&desc->addr, p))
 307                 ptr = p;
 308         return ptr;
 309 }
 310 #endif