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         /* prevent soft lockup/stalled CPU messages for endless loop. */
 147         rcu_sysrq_start();
 148         for (;;);
 149 }
 150
 151 void (*pm_power_off)(void) = machine_power_off;
 152 EXPORT_SYMBOL(pm_power_off);
 153
 154 void flush_thread(void)
 155 {
 156         /* Only needs to handle fpu stuff or perf monitors.
 157         ** REVISIT: several arches implement a "lazy fpu state".
 158         */
 159 }
 160
 161 void release_thread(struct task_struct *dead_task)
 162 {
 163 }
 164
 165 /*
 166  * Fill in the FPU structure for a core dump.
 167  */
 168
 169 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 170 {
 171         if (regs == NULL)
 172                 return 0;
 173
 174         memcpy(r, regs->fr, sizeof *r);
 175         return 1;
 176 }
 177
 178 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 179 {
 180         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 181         return 1;
 182 }
 183
 184 /*
 185  * Copy architecture-specific thread state
 186  */
 187 int
 188 copy_thread(unsigned long clone_flags, unsigned long usp,
 189             unsigned long kthread_arg, struct task_struct *p)
 190 {
 191         struct pt_regs *cregs = &(p->thread.regs);
 192         void *stack = task_stack_page(p);
 193
 194         /* We have to use void * instead of a function pointer, because
 195          * function pointers aren't a pointer to the function on 64-bit.
 196          * Make them const so the compiler knows they live in .text */
 197         extern void * const ret_from_kernel_thread;
 198         extern void * const child_return;
 199
 200         if (unlikely(p->flags & PF_KTHREAD)) {
 201                 /* kernel thread */
 202                 memset(cregs, 0, sizeof(struct pt_regs));
 203                 if (!usp) /* idle thread */
 204                         return 0;
 205                 /* Must exit via ret_from_kernel_thread in order
 206                  * to call schedule_tail()
 207                  */
 208                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 209                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 210                 /*
 211                  * Copy function and argument to be called from
 212                  * ret_from_kernel_thread.
 213                  */
 214 #ifdef CONFIG_64BIT
 215                 cregs->gr[27] = ((unsigned long *)usp)[3];
 216                 cregs->gr[26] = ((unsigned long *)usp)[2];
 217 #else
 218                 cregs->gr[26] = usp;
 219 #endif
 220                 cregs->gr[25] = kthread_arg;
 221         } else {
 222                 /* user thread */
 223                 /* usp must be word aligned.  This also prevents users from
 224                  * passing in the value 1 (which is the signal for a special
 225                  * return for a kernel thread) */
 226                 if (usp) {
 227                         usp = ALIGN(usp, 4);
 228                         if (likely(usp))
 229                                 cregs->gr[30] = usp;
 230                 }
 231                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 232                 cregs->kpc = (unsigned long) &child_return;
 233
 234                 /* Setup thread TLS area from the 4th parameter in clone */
 235                 if (clone_flags & CLONE_SETTLS)
 236                         cregs->cr27 = cregs->gr[23];
 237         }
 238
 239         return 0;
 240 }
 241
 242 unsigned long
 243 get_wchan(struct task_struct *p)
 244 {
 245         struct unwind_frame_info info;
 246         unsigned long ip;
 247         int count = 0;
 248
 249         if (!p || p == current || p->state == TASK_RUNNING)
 250                 return 0;
 251
 252         /*
 253          * These bracket the sleeping functions..
 254          */
 255
 256         unwind_frame_init_from_blocked_task(&info, p);
 257         do {
 258                 if (unwind_once(&info) < 0)
 259                         return 0;
 260                 ip = info.ip;
 261                 if (!in_sched_functions(ip))
 262                         return ip;
 263         } while (count++ < 16);
 264         return 0;
 265 }
 266
 267 #ifdef CONFIG_64BIT
 268 void *dereference_function_descriptor(void *ptr)
 269 {
 270         Elf64_Fdesc *desc = ptr;
 271         void *p;
 272
 273         if (!probe_kernel_address(&desc->addr, p))
 274                 ptr = p;
 275         return ptr;
 276 }
 277 #endif
 278
 279 static inline unsigned long brk_rnd(void)
 280 {
 281         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 282 }
 283
 284 unsigned long arch_randomize_brk(struct mm_struct *mm)
 285 {
 286         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
 287
 288         if (ret < mm->brk)
 289                 return mm->brk;
 290         return ret;
 291 }