arch/parisc/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *    PARISC Architecture-dependent parts of process handling
   4  *    based on the work for i386
   5  *
   6  *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   7  *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   8  *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   9  *    Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
  10  *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
  11  *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
  12  *    Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
  13  *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
  14  *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
  15  *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
  16  *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
  17  *    Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
  18  *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
  19  */
  20
  21 #include <stdarg.h>
  22
  23 #include <linux/elf.h>
  24 #include <linux/errno.h>
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/fs.h>
  28 #include <linux/cpu.h>
  29 #include <linux/module.h>
  30 #include <linux/personality.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/sched.h>
  33 #include <linux/sched/debug.h>
  34 #include <linux/sched/task.h>
  35 #include <linux/sched/task_stack.h>
  36 #include <linux/slab.h>
  37 #include <linux/stddef.h>
  38 #include <linux/unistd.h>
  39 #include <linux/kallsyms.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/rcupdate.h>
  42 #include <linux/random.h>
  43 #include <linux/nmi.h>
  44
  45 #include <asm/io.h>
  46 #include <asm/asm-offsets.h>
  47 #include <asm/assembly.h>
  48 #include <asm/pdc.h>
  49 #include <asm/pdc_chassis.h>
  50 #include <asm/unwind.h>
  51 #include <asm/sections.h>
  52
  53 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  54 #define CMD_RESET       5       /* reset any module */
  55
  56 /*
  57 ** The Wright Brothers and Gecko systems have a H/W problem
  58 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  59 ** the system. An HVERSION dependent PDC call was developed
  60 ** to perform a "safe", platform specific broadcast reset instead
  61 ** of kludging up all the code.
  62 **
  63 ** Older machines which do not implement PDC_BROADCAST_RESET will
  64 ** return (with an error) and the regular broadcast reset can be
  65 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  66 ** the PDC call will not return (the system will be reset).
  67 */
  68 void machine_restart(char *cmd)
  69 {
  70 #ifdef FASTBOOT_SELFTEST_SUPPORT
  71         /*
  72          ** If user has modified the Firmware Selftest Bitmap,
  73          ** run the tests specified in the bitmap after the
  74          ** system is rebooted w/PDC_DO_RESET.
  75          **
  76          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
  77          **
  78          ** Using "directed resets" at each processor with the MEM_TOC
  79          ** vector cleared will also avoid running destructive
  80          ** memory self tests. (Not implemented yet)
  81          */
  82         if (ftc_bitmap) {
  83                 pdc_do_firm_test_reset(ftc_bitmap);
  84         }
  85 #endif
  86         /* set up a new led state on systems shipped with a LED State panel */
  87         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
  88
  89         /* "Normal" system reset */
  90         pdc_do_reset();
  91
  92         /* Nope...box should reset with just CMD_RESET now */
  93         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
  94
  95         /* Wait for RESET to lay us to rest. */
  96         while (1) ;
  97
  98 }
  99
 100 void (*chassis_power_off)(void);
 101
 102 /*
 103  * This routine is called from sys_reboot to actually turn off the
 104  * machine
 105  */
 106 void machine_power_off(void)
 107 {
 108         /* If there is a registered power off handler, call it. */
 109         if (chassis_power_off)
 110                 chassis_power_off();
 111
 112         /* Put the soft power button back under hardware control.
 113          * If the user had already pressed the power button, the
 114          * following call will immediately power off. */
 115         pdc_soft_power_button(0);
 116
 117         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 118
 119         /* ipmi_poweroff may have been installed. */
 120         if (pm_power_off)
 121                 pm_power_off();
 122
 123         /* It seems we have no way to power the system off via
 124          * software. The user has to press the button himself. */
 125
 126         printk(KERN_EMERG "System shut down completed.\n"
 127                "Please power this system off now.");
 128
 129         /* prevent soft lockup/stalled CPU messages for endless loop. */
 130         rcu_sysrq_start();
 131         lockup_detector_soft_poweroff();
 132         for (;;);
 133 }
 134
 135 void (*pm_power_off)(void);
 136 EXPORT_SYMBOL(pm_power_off);
 137
 138 void machine_halt(void)
 139 {
 140         machine_power_off();
 141 }
 142
 143 void flush_thread(void)
 144 {
 145         /* Only needs to handle fpu stuff or perf monitors.
 146         ** REVISIT: several arches implement a "lazy fpu state".
 147         */
 148 }
 149
 150 void release_thread(struct task_struct *dead_task)
 151 {
 152 }
 153
 154 /*
 155  * Idle thread support
 156  *
 157  * Detect when running on QEMU with SeaBIOS PDC Firmware and let
 158  * QEMU idle the host too.
 159  */
 160
 161 int running_on_qemu __ro_after_init;
 162 EXPORT_SYMBOL(running_on_qemu);
 163
 164 void __cpuidle arch_cpu_idle_dead(void)
 165 {
 166         /* nop on real hardware, qemu will offline CPU. */
 167         asm volatile("or %%r31,%%r31,%%r31\n":::);
 168 }
 169
 170 void __cpuidle arch_cpu_idle(void)
 171 {
 172         raw_local_irq_enable();
 173
 174         /* nop on real hardware, qemu will idle sleep. */
 175         asm volatile("or %%r10,%%r10,%%r10\n":::);
 176 }
 177
 178 static int __init parisc_idle_init(void)
 179 {
 180         if (!running_on_qemu)
 181                 cpu_idle_poll_ctrl(1);
 182
 183         return 0;
 184 }
 185 arch_initcall(parisc_idle_init);
 186
 187 /*
 188  * Copy architecture-specific thread state
 189  */
 190 int
 191 copy_thread(unsigned long clone_flags, unsigned long usp,
 192             unsigned long kthread_arg, struct task_struct *p, unsigned long tls)
 193 {
 194         struct pt_regs *cregs = &(p->thread.regs);
 195         void *stack = task_stack_page(p);
 196
 197         /* We have to use void * instead of a function pointer, because
 198          * function pointers aren't a pointer to the function on 64-bit.
 199          * Make them const so the compiler knows they live in .text */
 200         extern void * const ret_from_kernel_thread;
 201         extern void * const child_return;
 202
 203         if (unlikely(p->flags & PF_KTHREAD)) {
 204                 /* kernel thread */
 205                 memset(cregs, 0, sizeof(struct pt_regs));
 206                 if (!usp) /* idle thread */
 207                         return 0;
 208                 /* Must exit via ret_from_kernel_thread in order
 209                  * to call schedule_tail()
 210                  */
 211                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 212                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 213                 /*
 214                  * Copy function and argument to be called from
 215                  * ret_from_kernel_thread.
 216                  */
 217 #ifdef CONFIG_64BIT
 218                 cregs->gr[27] = ((unsigned long *)usp)[3];
 219                 cregs->gr[26] = ((unsigned long *)usp)[2];
 220 #else
 221                 cregs->gr[26] = usp;
 222 #endif
 223                 cregs->gr[25] = kthread_arg;
 224         } else {
 225                 /* user thread */
 226                 /* usp must be word aligned.  This also prevents users from
 227                  * passing in the value 1 (which is the signal for a special
 228                  * return for a kernel thread) */
 229                 if (usp) {
 230                         usp = ALIGN(usp, 4);
 231                         if (likely(usp))
 232                                 cregs->gr[30] = usp;
 233                 }
 234                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 235                 cregs->kpc = (unsigned long) &child_return;
 236
 237                 /* Setup thread TLS area */
 238                 if (clone_flags & CLONE_SETTLS)
 239                         cregs->cr27 = tls;
 240         }
 241
 242         return 0;
 243 }
 244
 245 unsigned long
 246 get_wchan(struct task_struct *p)
 247 {
 248         struct unwind_frame_info info;
 249         unsigned long ip;
 250         int count = 0;
 251
 252         if (!p || p == current || p->state == TASK_RUNNING)
 253                 return 0;
 254
 255         /*
 256          * These bracket the sleeping functions..
 257          */
 258
 259         unwind_frame_init_from_blocked_task(&info, p);
 260         do {
 261                 if (unwind_once(&info) < 0)
 262                         return 0;
 263                 ip = info.ip;
 264                 if (!in_sched_functions(ip))
 265                         return ip;
 266         } while (count++ < MAX_UNWIND_ENTRIES);
 267         return 0;
 268 }
 269
 270 #ifdef CONFIG_64BIT
 271 void *dereference_function_descriptor(void *ptr)
 272 {
 273         Elf64_Fdesc *desc = ptr;
 274         void *p;
 275
 276         if (!get_kernel_nofault(p, (void *)&desc->addr))
 277                 ptr = p;
 278         return ptr;
 279 }
 280
 281 void *dereference_kernel_function_descriptor(void *ptr)
 282 {
 283         if (ptr < (void *)__start_opd ||
 284                         ptr >= (void *)__end_opd)
 285                 return ptr;
 286
 287         return dereference_function_descriptor(ptr);
 288 }
 289 #endif
 290
 291 static inline unsigned long brk_rnd(void)
 292 {
 293         return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
 294 }
 295
 296 unsigned long arch_randomize_brk(struct mm_struct *mm)
 297 {
 298         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
 299
 300         if (ret < mm->brk)
 301                 return mm->brk;
 302         return ret;
 303 }