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