arch/arm64/kernel/process.c

   1 /*
   2  * Based on arch/arm/kernel/process.c
   3  *
   4  * Original Copyright (C) 1995  Linus Torvalds
   5  * Copyright (C) 1996-2000 Russell King - Converted to ARM.
   6  * Copyright (C) 2012 ARM Ltd.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stdarg.h>
  22
  23 #include <linux/export.h>
  24 #include <linux/sched.h>
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/stddef.h>
  28 #include <linux/unistd.h>
  29 #include <linux/user.h>
  30 #include <linux/delay.h>
  31 #include <linux/reboot.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/kallsyms.h>
  34 #include <linux/init.h>
  35 #include <linux/cpu.h>
  36 #include <linux/elfcore.h>
  37 #include <linux/pm.h>
  38 #include <linux/tick.h>
  39 #include <linux/utsname.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/random.h>
  42 #include <linux/hw_breakpoint.h>
  43 #include <linux/personality.h>
  44 #include <linux/notifier.h>
  45
  46 #include <asm/compat.h>
  47 #include <asm/cacheflush.h>
  48 #include <asm/fpsimd.h>
  49 #include <asm/mmu_context.h>
  50 #include <asm/processor.h>
  51 #include <asm/stacktrace.h>
  52
  53 static void setup_restart(void)
  54 {
  55         /*
  56          * Tell the mm system that we are going to reboot -
  57          * we may need it to insert some 1:1 mappings so that
  58          * soft boot works.
  59          */
  60         setup_mm_for_reboot();
  61
  62         /* Clean and invalidate caches */
  63         flush_cache_all();
  64
  65         /* Turn D-cache off */
  66         cpu_cache_off();
  67
  68         /* Push out any further dirty data, and ensure cache is empty */
  69         flush_cache_all();
  70 }
  71
  72 void soft_restart(unsigned long addr)
  73 {
  74         typedef void (*phys_reset_t)(unsigned long);
  75         phys_reset_t phys_reset;
  76
  77         setup_restart();
  78
  79         /* Switch to the identity mapping */
  80         phys_reset = (phys_reset_t)virt_to_phys(cpu_reset);
  81         phys_reset(addr);
  82
  83         /* Should never get here */
  84         BUG();
  85 }
  86
  87 /*
  88  * Function pointers to optional machine specific functions
  89  */
  90 void (*pm_power_off)(void);
  91 EXPORT_SYMBOL_GPL(pm_power_off);
  92
  93 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
  94 EXPORT_SYMBOL_GPL(arm_pm_restart);
  95
  96 /*
  97  * This is our default idle handler.
  98  */
  99 void arch_cpu_idle(void)
 100 {
 101         /*
 102          * This should do all the clock switching and wait for interrupt
 103          * tricks
 104          */
 105         cpu_do_idle();
 106         local_irq_enable();
 107 }
 108
 109 #ifdef CONFIG_HOTPLUG_CPU
 110 void arch_cpu_idle_dead(void)
 111 {
 112        cpu_die();
 113 }
 114 #endif
 115
 116 void machine_shutdown(void)
 117 {
 118 #ifdef CONFIG_SMP
 119         smp_send_stop();
 120 #endif
 121 }
 122
 123 void machine_halt(void)
 124 {
 125         machine_shutdown();
 126         while (1);
 127 }
 128
 129 void machine_power_off(void)
 130 {
 131         machine_shutdown();
 132         if (pm_power_off)
 133                 pm_power_off();
 134 }
 135
 136 void machine_restart(char *cmd)
 137 {
 138         machine_shutdown();
 139
 140         /* Disable interrupts first */
 141         local_irq_disable();
 142
 143         /* Now call the architecture specific reboot code. */
 144         if (arm_pm_restart)
 145                 arm_pm_restart(reboot_mode, cmd);
 146
 147         /*
 148          * Whoops - the architecture was unable to reboot.
 149          */
 150         printk("Reboot failed -- System halted\n");
 151         while (1);
 152 }
 153
 154 void __show_regs(struct pt_regs *regs)
 155 {
 156         int i, top_reg;
 157         u64 lr, sp;
 158
 159         if (compat_user_mode(regs)) {
 160                 lr = regs->compat_lr;
 161                 sp = regs->compat_sp;
 162                 top_reg = 12;
 163         } else {
 164                 lr = regs->regs[30];
 165                 sp = regs->sp;
 166                 top_reg = 29;
 167         }
 168
 169         show_regs_print_info(KERN_DEFAULT);
 170         print_symbol("PC is at %s\n", instruction_pointer(regs));
 171         print_symbol("LR is at %s\n", lr);
 172         printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 173                regs->pc, lr, regs->pstate);
 174         printk("sp : %016llx\n", sp);
 175         for (i = top_reg; i >= 0; i--) {
 176                 printk("x%-2d: %016llx ", i, regs->regs[i]);
 177                 if (i % 2 == 0)
 178                         printk("\n");
 179         }
 180         printk("\n");
 181 }
 182
 183 void show_regs(struct pt_regs * regs)
 184 {
 185         printk("\n");
 186         __show_regs(regs);
 187 }
 188
 189 /*
 190  * Free current thread data structures etc..
 191  */
 192 void exit_thread(void)
 193 {
 194 }
 195
 196 void flush_thread(void)
 197 {
 198         fpsimd_flush_thread();
 199         flush_ptrace_hw_breakpoint(current);
 200 }
 201
 202 void release_thread(struct task_struct *dead_task)
 203 {
 204 }
 205
 206 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 207 {
 208         fpsimd_save_state(&current->thread.fpsimd_state);
 209         *dst = *src;
 210         return 0;
 211 }
 212
 213 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 214
 215 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 216                 unsigned long stk_sz, struct task_struct *p)
 217 {
 218         struct pt_regs *childregs = task_pt_regs(p);
 219         unsigned long tls = p->thread.tp_value;
 220
 221         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 222
 223         if (likely(!(p->flags & PF_KTHREAD))) {
 224                 *childregs = *current_pt_regs();
 225                 childregs->regs[0] = 0;
 226                 if (is_compat_thread(task_thread_info(p))) {
 227                         if (stack_start)
 228                                 childregs->compat_sp = stack_start;
 229                 } else {
 230                         /*
 231                          * Read the current TLS pointer from tpidr_el0 as it may be
 232                          * out-of-sync with the saved value.
 233                          */
 234                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 235                         if (stack_start) {
 236                                 /* 16-byte aligned stack mandatory on AArch64 */
 237                                 if (stack_start & 15)
 238                                         return -EINVAL;
 239                                 childregs->sp = stack_start;
 240                         }
 241                 }
 242                 /*
 243                  * If a TLS pointer was passed to clone (4th argument), use it
 244                  * for the new thread.
 245                  */
 246                 if (clone_flags & CLONE_SETTLS)
 247                         tls = childregs->regs[3];
 248         } else {
 249                 memset(childregs, 0, sizeof(struct pt_regs));
 250                 childregs->pstate = PSR_MODE_EL1h;
 251                 p->thread.cpu_context.x19 = stack_start;
 252                 p->thread.cpu_context.x20 = stk_sz;
 253         }
 254         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 255         p->thread.cpu_context.sp = (unsigned long)childregs;
 256         p->thread.tp_value = tls;
 257
 258         ptrace_hw_copy_thread(p);
 259
 260         return 0;
 261 }
 262
 263 static void tls_thread_switch(struct task_struct *next)
 264 {
 265         unsigned long tpidr, tpidrro;
 266
 267         if (!is_compat_task()) {
 268                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 269                 current->thread.tp_value = tpidr;
 270         }
 271
 272         if (is_compat_thread(task_thread_info(next))) {
 273                 tpidr = 0;
 274                 tpidrro = next->thread.tp_value;
 275         } else {
 276                 tpidr = next->thread.tp_value;
 277                 tpidrro = 0;
 278         }
 279
 280         asm(
 281         "       msr     tpidr_el0, %0\n"
 282         "       msr     tpidrro_el0, %1"
 283         : : "r" (tpidr), "r" (tpidrro));
 284 }
 285
 286 /*
 287  * Thread switching.
 288  */
 289 struct task_struct *__switch_to(struct task_struct *prev,
 290                                 struct task_struct *next)
 291 {
 292         struct task_struct *last;
 293
 294         fpsimd_thread_switch(next);
 295         tls_thread_switch(next);
 296         hw_breakpoint_thread_switch(next);
 297         contextidr_thread_switch(next);
 298
 299         /*
 300          * Complete any pending TLB or cache maintenance on this CPU in case
 301          * the thread migrates to a different CPU.
 302          */
 303         dsb();
 304
 305         /* the actual thread switch */
 306         last = cpu_switch_to(prev, next);
 307
 308         return last;
 309 }
 310
 311 unsigned long get_wchan(struct task_struct *p)
 312 {
 313         struct stackframe frame;
 314         unsigned long stack_page;
 315         int count = 0;
 316         if (!p || p == current || p->state == TASK_RUNNING)
 317                 return 0;
 318
 319         frame.fp = thread_saved_fp(p);
 320         frame.sp = thread_saved_sp(p);
 321         frame.pc = thread_saved_pc(p);
 322         stack_page = (unsigned long)task_stack_page(p);
 323         do {
 324                 if (frame.sp < stack_page ||
 325                     frame.sp >= stack_page + THREAD_SIZE ||
 326                     unwind_frame(&frame))
 327                         return 0;
 328                 if (!in_sched_functions(frame.pc))
 329                         return frame.pc;
 330         } while (count ++ < 16);
 331         return 0;
 332 }
 333
 334 unsigned long arch_align_stack(unsigned long sp)
 335 {
 336         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 337                 sp -= get_random_int() & ~PAGE_MASK;
 338         return sp & ~0xf;
 339 }
 340
 341 static unsigned long randomize_base(unsigned long base)
 342 {
 343         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 344         return randomize_range(base, range_end, 0) ? : base;
 345 }
 346
 347 unsigned long arch_randomize_brk(struct mm_struct *mm)
 348 {
 349         return randomize_base(mm->brk);
 350 }
 351
 352 unsigned long randomize_et_dyn(unsigned long base)
 353 {
 354         return randomize_base(base);
 355 }