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) 2001-2014 Helge Deller <deller@gmx.de>
  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 #include <linux/random.h>
  53
  54 #include <asm/io.h>
  55 #include <asm/asm-offsets.h>
  56 #include <asm/assembly.h>
  57 #include <asm/pdc.h>
  58 #include <asm/pdc_chassis.h>
  59 #include <asm/pgalloc.h>
  60 #include <asm/unwind.h>
  61 #include <asm/sections.h>
  62
  63 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  64 #define CMD_RESET       5       /* reset any module */
  65
  66 /*
  67 ** The Wright Brothers and Gecko systems have a H/W problem
  68 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  69 ** the system. An HVERSION dependent PDC call was developed
  70 ** to perform a "safe", platform specific broadcast reset instead
  71 ** of kludging up all the code.
  72 **
  73 ** Older machines which do not implement PDC_BROADCAST_RESET will
  74 ** return (with an error) and the regular broadcast reset can be
  75 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  76 ** the PDC call will not return (the system will be reset).
  77 */
  78 void machine_restart(char *cmd)
  79 {
  80 #ifdef FASTBOOT_SELFTEST_SUPPORT
  81         /*
  82          ** If user has modified the Firmware Selftest Bitmap,
  83          ** run the tests specified in the bitmap after the
  84          ** system is rebooted w/PDC_DO_RESET.
  85          **
  86          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
  87          **
  88          ** Using "directed resets" at each processor with the MEM_TOC
  89          ** vector cleared will also avoid running destructive
  90          ** memory self tests. (Not implemented yet)
  91          */
  92         if (ftc_bitmap) {
  93                 pdc_do_firm_test_reset(ftc_bitmap);
  94         }
  95 #endif
  96         /* set up a new led state on systems shipped with a LED State panel */
  97         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
  98
  99         /* "Normal" system reset */
 100         pdc_do_reset();
 101
 102         /* Nope...box should reset with just CMD_RESET now */
 103         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 104
 105         /* Wait for RESET to lay us to rest. */
 106         while (1) ;
 107
 108 }
 109
 110 void machine_halt(void)
 111 {
 112         /*
 113         ** The LED/ChassisCodes are updated by the led_halt()
 114         ** function, called by the reboot notifier chain.
 115         */
 116 }
 117
 118 void (*chassis_power_off)(void);
 119
 120 /*
 121  * This routine is called from sys_reboot to actually turn off the
 122  * machine
 123  */
 124 void machine_power_off(void)
 125 {
 126         /* If there is a registered power off handler, call it. */
 127         if (chassis_power_off)
 128                 chassis_power_off();
 129
 130         /* Put the soft power button back under hardware control.
 131          * If the user had already pressed the power button, the
 132          * following call will immediately power off. */
 133         pdc_soft_power_button(0);
 134
 135         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 136
 137         /* It seems we have no way to power the system off via
 138          * software. The user has to press the button himself. */
 139
 140         printk(KERN_EMERG "System shut down completed.\n"
 141                "Please power this system off now.");
 142 }
 143
 144 void (*pm_power_off)(void) = machine_power_off;
 145 EXPORT_SYMBOL(pm_power_off);
 146
 147 void flush_thread(void)
 148 {
 149         /* Only needs to handle fpu stuff or perf monitors.
 150         ** REVISIT: several arches implement a "lazy fpu state".
 151         */
 152 }
 153
 154 void release_thread(struct task_struct *dead_task)
 155 {
 156 }
 157
 158 /*
 159  * Fill in the FPU structure for a core dump.
 160  */
 161
 162 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 163 {
 164         if (regs == NULL)
 165                 return 0;
 166
 167         memcpy(r, regs->fr, sizeof *r);
 168         return 1;
 169 }
 170
 171 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 172 {
 173         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 174         return 1;
 175 }
 176
 177 /*
 178  * Copy architecture-specific thread state
 179  */
 180 int
 181 copy_thread(unsigned long clone_flags, unsigned long usp,
 182             unsigned long kthread_arg, struct task_struct *p)
 183 {
 184         struct pt_regs *cregs = &(p->thread.regs);
 185         void *stack = task_stack_page(p);
 186
 187         /* We have to use void * instead of a function pointer, because
 188          * function pointers aren't a pointer to the function on 64-bit.
 189          * Make them const so the compiler knows they live in .text */
 190         extern void * const ret_from_kernel_thread;
 191         extern void * const child_return;
 192
 193         if (unlikely(p->flags & PF_KTHREAD)) {
 194                 /* kernel thread */
 195                 memset(cregs, 0, sizeof(struct pt_regs));
 196                 if (!usp) /* idle thread */
 197                         return 0;
 198                 /* Must exit via ret_from_kernel_thread in order
 199                  * to call schedule_tail()
 200                  */
 201                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 202                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 203                 /*
 204                  * Copy function and argument to be called from
 205                  * ret_from_kernel_thread.
 206                  */
 207 #ifdef CONFIG_64BIT
 208                 cregs->gr[27] = ((unsigned long *)usp)[3];
 209                 cregs->gr[26] = ((unsigned long *)usp)[2];
 210 #else
 211                 cregs->gr[26] = usp;
 212 #endif
 213                 cregs->gr[25] = kthread_arg;
 214         } else {
 215                 /* user thread */
 216                 /* usp must be word aligned.  This also prevents users from
 217                  * passing in the value 1 (which is the signal for a special
 218                  * return for a kernel thread) */
 219                 if (usp) {
 220                         usp = ALIGN(usp, 4);
 221                         if (likely(usp))
 222                                 cregs->gr[30] = usp;
 223                 }
 224                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 225                 cregs->kpc = (unsigned long) &child_return;
 226
 227                 /* Setup thread TLS area from the 4th parameter in clone */
 228                 if (clone_flags & CLONE_SETTLS)
 229                         cregs->cr27 = cregs->gr[23];
 230         }
 231
 232         return 0;
 233 }
 234
 235 unsigned long thread_saved_pc(struct task_struct *t)
 236 {
 237         return t->thread.regs.kpc;
 238 }
 239
 240 unsigned long
 241 get_wchan(struct task_struct *p)
 242 {
 243         struct unwind_frame_info info;
 244         unsigned long ip;
 245         int count = 0;
 246
 247         if (!p || p == current || p->state == TASK_RUNNING)
 248                 return 0;
 249
 250         /*
 251          * These bracket the sleeping functions..
 252          */
 253
 254         unwind_frame_init_from_blocked_task(&info, p);
 255         do {
 256                 if (unwind_once(&info) < 0)
 257                         return 0;
 258                 ip = info.ip;
 259                 if (!in_sched_functions(ip))
 260                         return ip;
 261         } while (count++ < 16);
 262         return 0;
 263 }
 264
 265 #ifdef CONFIG_64BIT
 266 void *dereference_function_descriptor(void *ptr)
 267 {
 268         Elf64_Fdesc *desc = ptr;
 269         void *p;
 270
 271         if (!probe_kernel_address(&desc->addr, p))
 272                 ptr = p;
 273         return ptr;
 274 }
 275 #endif
 276
 277 static inline unsigned long brk_rnd(void)
 278 {
 279         /* 8MB for 32bit, 1GB for 64bit */
 280         if (is_32bit_task())
 281                 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
 282         else
 283                 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
 284 }
 285
 286 unsigned long arch_randomize_brk(struct mm_struct *mm)
 287 {
 288         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
 289
 290         if (ret < mm->brk)
 291                 return mm->brk;
 292         return ret;
 293 }