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