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 (*chassis_power_off)(void);
 116
 117 /*
 118  * This routine is called from sys_reboot to actually turn off the
 119  * machine
 120  */
 121 void machine_power_off(void)
 122 {
 123         /* If there is a registered power off handler, call it. */
 124         if (chassis_power_off)
 125                 chassis_power_off();
 126
 127         /* Put the soft power button back under hardware control.
 128          * If the user had already pressed the power button, the
 129          * following call will immediately power off. */
 130         pdc_soft_power_button(0);
 131
 132         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 133
 134         /* ipmi_poweroff may have been installed. */
 135         if (pm_power_off)
 136                 pm_power_off();
 137
 138         /* It seems we have no way to power the system off via
 139          * software. The user has to press the button himself. */
 140
 141         printk(KERN_EMERG "System shut down completed.\n"
 142                "Please power this system off now.");
 143
 144         /* prevent soft lockup/stalled CPU messages for endless loop. */
 145         rcu_sysrq_start();
 146         lockup_detector_soft_poweroff();
 147         for (;;);
 148 }
 149
 150 void (*pm_power_off)(void);
 151 EXPORT_SYMBOL(pm_power_off);
 152
 153 void machine_halt(void)
 154 {
 155         machine_power_off();
 156 }
 157
 158 void flush_thread(void)
 159 {
 160         /* Only needs to handle fpu stuff or perf monitors.
 161         ** REVISIT: several arches implement a "lazy fpu state".
 162         */
 163 }
 164
 165 void release_thread(struct task_struct *dead_task)
 166 {
 167 }
 168
 169 /*
 170  * Fill in the FPU structure for a core dump.
 171  */
 172
 173 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 174 {
 175         if (regs == NULL)
 176                 return 0;
 177
 178         memcpy(r, regs->fr, sizeof *r);
 179         return 1;
 180 }
 181
 182 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 183 {
 184         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 185         return 1;
 186 }
 187
 188 /*
 189  * Idle thread support
 190  *
 191  * Detect when running on QEMU with SeaBIOS PDC Firmware and let
 192  * QEMU idle the host too.
 193  */
 194
 195 int running_on_qemu __read_mostly;
 196
 197 void __cpuidle arch_cpu_idle_dead(void)
 198 {
 199         /* nop on real hardware, qemu will offline CPU. */
 200         asm volatile("or %%r31,%%r31,%%r31\n":::);
 201 }
 202
 203 void __cpuidle arch_cpu_idle(void)
 204 {
 205         local_irq_enable();
 206
 207         /* nop on real hardware, qemu will idle sleep. */
 208         asm volatile("or %%r10,%%r10,%%r10\n":::);
 209 }
 210
 211 static int __init parisc_idle_init(void)
 212 {
 213         const char *marker;
 214
 215         /* check QEMU/SeaBIOS marker in PAGE0 */
 216         marker = (char *) &PAGE0->pad0;
 217         running_on_qemu = (memcmp(marker, "SeaBIOS", 8) == 0);
 218
 219         if (!running_on_qemu)
 220                 cpu_idle_poll_ctrl(1);
 221
 222         return 0;
 223 }
 224 arch_initcall(parisc_idle_init);
 225
 226 /*
 227  * Copy architecture-specific thread state
 228  */
 229 int
 230 copy_thread(unsigned long clone_flags, unsigned long usp,
 231             unsigned long kthread_arg, struct task_struct *p)
 232 {
 233         struct pt_regs *cregs = &(p->thread.regs);
 234         void *stack = task_stack_page(p);
 235
 236         /* We have to use void * instead of a function pointer, because
 237          * function pointers aren't a pointer to the function on 64-bit.
 238          * Make them const so the compiler knows they live in .text */
 239         extern void * const ret_from_kernel_thread;
 240         extern void * const child_return;
 241
 242         if (unlikely(p->flags & PF_KTHREAD)) {
 243                 /* kernel thread */
 244                 memset(cregs, 0, sizeof(struct pt_regs));
 245                 if (!usp) /* idle thread */
 246                         return 0;
 247                 /* Must exit via ret_from_kernel_thread in order
 248                  * to call schedule_tail()
 249                  */
 250                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 251                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 252                 /*
 253                  * Copy function and argument to be called from
 254                  * ret_from_kernel_thread.
 255                  */
 256 #ifdef CONFIG_64BIT
 257                 cregs->gr[27] = ((unsigned long *)usp)[3];
 258                 cregs->gr[26] = ((unsigned long *)usp)[2];
 259 #else
 260                 cregs->gr[26] = usp;
 261 #endif
 262                 cregs->gr[25] = kthread_arg;
 263         } else {
 264                 /* user thread */
 265                 /* usp must be word aligned.  This also prevents users from
 266                  * passing in the value 1 (which is the signal for a special
 267                  * return for a kernel thread) */
 268                 if (usp) {
 269                         usp = ALIGN(usp, 4);
 270                         if (likely(usp))
 271                                 cregs->gr[30] = usp;
 272                 }
 273                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 274                 cregs->kpc = (unsigned long) &child_return;
 275
 276                 /* Setup thread TLS area from the 4th parameter in clone */
 277                 if (clone_flags & CLONE_SETTLS)
 278                         cregs->cr27 = cregs->gr[23];
 279         }
 280
 281         return 0;
 282 }
 283
 284 unsigned long
 285 get_wchan(struct task_struct *p)
 286 {
 287         struct unwind_frame_info info;
 288         unsigned long ip;
 289         int count = 0;
 290
 291         if (!p || p == current || p->state == TASK_RUNNING)
 292                 return 0;
 293
 294         /*
 295          * These bracket the sleeping functions..
 296          */
 297
 298         unwind_frame_init_from_blocked_task(&info, p);
 299         do {
 300                 if (unwind_once(&info) < 0)
 301                         return 0;
 302                 ip = info.ip;
 303                 if (!in_sched_functions(ip))
 304                         return ip;
 305         } while (count++ < 16);
 306         return 0;
 307 }
 308
 309 #ifdef CONFIG_64BIT
 310 void *dereference_function_descriptor(void *ptr)
 311 {
 312         Elf64_Fdesc *desc = ptr;
 313         void *p;
 314
 315         if (!probe_kernel_address(&desc->addr, p))
 316                 ptr = p;
 317         return ptr;
 318 }
 319
 320 void *dereference_kernel_function_descriptor(void *ptr)
 321 {
 322         if (ptr < (void *)__start_opd ||
 323                         ptr >= (void *)__end_opd)
 324                 return ptr;
 325
 326         return dereference_function_descriptor(ptr);
 327 }
 328 #endif
 329
 330 static inline unsigned long brk_rnd(void)
 331 {
 332         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 333 }
 334
 335 unsigned long arch_randomize_brk(struct mm_struct *mm)
 336 {
 337         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
 338
 339         if (ret < mm->brk)
 340                 return mm->brk;
 341         return ret;
 342 }