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