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/cpu.h>
  43 #include <linux/module.h>
  44 #include <linux/personality.h>
  45 #include <linux/ptrace.h>
  46 #include <linux/sched.h>
  47 #include <linux/sched/debug.h>
  48 #include <linux/sched/task.h>
  49 #include <linux/sched/task_stack.h>
  50 #include <linux/slab.h>
  51 #include <linux/stddef.h>
  52 #include <linux/unistd.h>
  53 #include <linux/kallsyms.h>
  54 #include <linux/uaccess.h>
  55 #include <linux/rcupdate.h>
  56 #include <linux/random.h>
  57 #include <linux/nmi.h>
  58
  59 #include <asm/io.h>
  60 #include <asm/asm-offsets.h>
  61 #include <asm/assembly.h>
  62 #include <asm/pdc.h>
  63 #include <asm/pdc_chassis.h>
  64 #include <asm/pgalloc.h>
  65 #include <asm/unwind.h>
  66 #include <asm/sections.h>
  67
  68 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  69 #define CMD_RESET       5       /* reset any module */
  70
  71 /*
  72 ** The Wright Brothers and Gecko systems have a H/W problem
  73 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  74 ** the system. An HVERSION dependent PDC call was developed
  75 ** to perform a "safe", platform specific broadcast reset instead
  76 ** of kludging up all the code.
  77 **
  78 ** Older machines which do not implement PDC_BROADCAST_RESET will
  79 ** return (with an error) and the regular broadcast reset can be
  80 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  81 ** the PDC call will not return (the system will be reset).
  82 */
  83 void machine_restart(char *cmd)
  84 {
  85 #ifdef FASTBOOT_SELFTEST_SUPPORT
  86         /*
  87          ** If user has modified the Firmware Selftest Bitmap,
  88          ** run the tests specified in the bitmap after the
  89          ** system is rebooted w/PDC_DO_RESET.
  90          **
  91          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
  92          **
  93          ** Using "directed resets" at each processor with the MEM_TOC
  94          ** vector cleared will also avoid running destructive
  95          ** memory self tests. (Not implemented yet)
  96          */
  97         if (ftc_bitmap) {
  98                 pdc_do_firm_test_reset(ftc_bitmap);
  99         }
 100 #endif
 101         /* set up a new led state on systems shipped with a LED State panel */
 102         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 103
 104         /* "Normal" system reset */
 105         pdc_do_reset();
 106
 107         /* Nope...box should reset with just CMD_RESET now */
 108         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 109
 110         /* Wait for RESET to lay us to rest. */
 111         while (1) ;
 112
 113 }
 114
 115 void machine_halt(void)
 116 {
 117         /*
 118         ** The LED/ChassisCodes are updated by the led_halt()
 119         ** function, called by the reboot notifier chain.
 120         */
 121 }
 122
 123 void (*chassis_power_off)(void);
 124
 125 /*
 126  * This routine is called from sys_reboot to actually turn off the
 127  * machine
 128  */
 129 void machine_power_off(void)
 130 {
 131         /* If there is a registered power off handler, call it. */
 132         if (chassis_power_off)
 133                 chassis_power_off();
 134
 135         /* Put the soft power button back under hardware control.
 136          * If the user had already pressed the power button, the
 137          * following call will immediately power off. */
 138         pdc_soft_power_button(0);
 139
 140         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 141
 142         /* It seems we have no way to power the system off via
 143          * software. The user has to press the button himself. */
 144
 145         printk(KERN_EMERG "System shut down completed.\n"
 146                "Please power this system off now.");
 147
 148         /* prevent soft lockup/stalled CPU messages for endless loop. */
 149         rcu_sysrq_start();
 150         lockup_detector_soft_poweroff();
 151         for (;;);
 152 }
 153
 154 void (*pm_power_off)(void) = machine_power_off;
 155 EXPORT_SYMBOL(pm_power_off);
 156
 157 void flush_thread(void)
 158 {
 159         /* Only needs to handle fpu stuff or perf monitors.
 160         ** REVISIT: several arches implement a "lazy fpu state".
 161         */
 162 }
 163
 164 void release_thread(struct task_struct *dead_task)
 165 {
 166 }
 167
 168 /*
 169  * Fill in the FPU structure for a core dump.
 170  */
 171
 172 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 173 {
 174         if (regs == NULL)
 175                 return 0;
 176
 177         memcpy(r, regs->fr, sizeof *r);
 178         return 1;
 179 }
 180
 181 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 182 {
 183         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 184         return 1;
 185 }
 186
 187 /*
 188  * Idle thread support
 189  *
 190  * Detect when running on QEMU with SeaBIOS PDC Firmware and let
 191  * QEMU idle the host too.
 192  */
 193
 194 int running_on_qemu __read_mostly;
 195
 196 void __cpuidle arch_cpu_idle_dead(void)
 197 {
 198         /* nop on real hardware, qemu will offline CPU. */
 199         asm volatile("or %%r31,%%r31,%%r31\n":::);
 200 }
 201
 202 void __cpuidle arch_cpu_idle(void)
 203 {
 204         local_irq_enable();
 205
 206         /* nop on real hardware, qemu will idle sleep. */
 207         asm volatile("or %%r10,%%r10,%%r10\n":::);
 208 }
 209
 210 static int __init parisc_idle_init(void)
 211 {
 212         const char *marker;
 213
 214         /* check QEMU/SeaBIOS marker in PAGE0 */
 215         marker = (char *) &PAGE0->pad0;
 216         running_on_qemu = (memcmp(marker, "SeaBIOS", 8) == 0);
 217
 218         if (!running_on_qemu)
 219                 cpu_idle_poll_ctrl(1);
 220
 221         return 0;
 222 }
 223 arch_initcall(parisc_idle_init);
 224
 225 /*
 226  * Copy architecture-specific thread state
 227  */
 228 int
 229 copy_thread(unsigned long clone_flags, unsigned long usp,
 230             unsigned long kthread_arg, struct task_struct *p)
 231 {
 232         struct pt_regs *cregs = &(p->thread.regs);
 233         void *stack = task_stack_page(p);
 234
 235         /* We have to use void * instead of a function pointer, because
 236          * function pointers aren't a pointer to the function on 64-bit.
 237          * Make them const so the compiler knows they live in .text */
 238         extern void * const ret_from_kernel_thread;
 239         extern void * const child_return;
 240
 241         if (unlikely(p->flags & PF_KTHREAD)) {
 242                 /* kernel thread */
 243                 memset(cregs, 0, sizeof(struct pt_regs));
 244                 if (!usp) /* idle thread */
 245                         return 0;
 246                 /* Must exit via ret_from_kernel_thread in order
 247                  * to call schedule_tail()
 248                  */
 249                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 250                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 251                 /*
 252                  * Copy function and argument to be called from
 253                  * ret_from_kernel_thread.
 254                  */
 255 #ifdef CONFIG_64BIT
 256                 cregs->gr[27] = ((unsigned long *)usp)[3];
 257                 cregs->gr[26] = ((unsigned long *)usp)[2];
 258 #else
 259                 cregs->gr[26] = usp;
 260 #endif
 261                 cregs->gr[25] = kthread_arg;
 262         } else {
 263                 /* user thread */
 264                 /* usp must be word aligned.  This also prevents users from
 265                  * passing in the value 1 (which is the signal for a special
 266                  * return for a kernel thread) */
 267                 if (usp) {
 268                         usp = ALIGN(usp, 4);
 269                         if (likely(usp))
 270                                 cregs->gr[30] = usp;
 271                 }
 272                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 273                 cregs->kpc = (unsigned long) &child_return;
 274
 275                 /* Setup thread TLS area from the 4th parameter in clone */
 276                 if (clone_flags & CLONE_SETTLS)
 277                         cregs->cr27 = cregs->gr[23];
 278         }
 279
 280         return 0;
 281 }
 282
 283 unsigned long
 284 get_wchan(struct task_struct *p)
 285 {
 286         struct unwind_frame_info info;
 287         unsigned long ip;
 288         int count = 0;
 289
 290         if (!p || p == current || p->state == TASK_RUNNING)
 291                 return 0;
 292
 293         /*
 294          * These bracket the sleeping functions..
 295          */
 296
 297         unwind_frame_init_from_blocked_task(&info, p);
 298         do {
 299                 if (unwind_once(&info) < 0)
 300                         return 0;
 301                 ip = info.ip;
 302                 if (!in_sched_functions(ip))
 303                         return ip;
 304         } while (count++ < 16);
 305         return 0;
 306 }
 307
 308 #ifdef CONFIG_64BIT
 309 void *dereference_function_descriptor(void *ptr)
 310 {
 311         Elf64_Fdesc *desc = ptr;
 312         void *p;
 313
 314         if (!probe_kernel_address(&desc->addr, p))
 315                 ptr = p;
 316         return ptr;
 317 }
 318
 319 void *dereference_kernel_function_descriptor(void *ptr)
 320 {
 321         if (ptr < (void *)__start_opd ||
 322                         ptr >= (void *)__end_opd)
 323                 return ptr;
 324
 325         return dereference_function_descriptor(ptr);
 326 }
 327 #endif
 328
 329 static inline unsigned long brk_rnd(void)
 330 {
 331         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 332 }
 333
 334 unsigned long arch_randomize_brk(struct mm_struct *mm)
 335 {
 336         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
 337
 338         if (ret < mm->brk)
 339                 return mm->brk;
 340         return ret;
 341 }