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/cpuidle.h>
  37 #include <linux/elfcore.h>
  38 #include <linux/pm.h>
  39 #include <linux/tick.h>
  40 #include <linux/utsname.h>
  41 #include <linux/uaccess.h>
  42 #include <linux/random.h>
  43 #include <linux/hw_breakpoint.h>
  44 #include <linux/personality.h>
  45 #include <linux/notifier.h>
  46
  47 #include <asm/compat.h>
  48 #include <asm/cacheflush.h>
  49 #include <asm/fpsimd.h>
  50 #include <asm/mmu_context.h>
  51 #include <asm/processor.h>
  52 #include <asm/stacktrace.h>
  53
  54 static void setup_restart(void)
  55 {
  56         /*
  57          * Tell the mm system that we are going to reboot -
  58          * we may need it to insert some 1:1 mappings so that
  59          * soft boot works.
  60          */
  61         setup_mm_for_reboot();
  62
  63         /* Clean and invalidate caches */
  64         flush_cache_all();
  65
  66         /* Turn D-cache off */
  67         cpu_cache_off();
  68
  69         /* Push out any further dirty data, and ensure cache is empty */
  70         flush_cache_all();
  71 }
  72
  73 void soft_restart(unsigned long addr)
  74 {
  75         setup_restart();
  76         cpu_reset(addr);
  77 }
  78
  79 /*
  80  * Function pointers to optional machine specific functions
  81  */
  82 void (*pm_power_off)(void);
  83 EXPORT_SYMBOL_GPL(pm_power_off);
  84
  85 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
  86 EXPORT_SYMBOL_GPL(arm_pm_restart);
  87
  88 /*
  89  * This is our default idle handler.
  90  */
  91 void arch_cpu_idle(void)
  92 {
  93         /*
  94          * This should do all the clock switching and wait for interrupt
  95          * tricks
  96          */
  97         if (cpuidle_idle_call()) {
  98                 cpu_do_idle();
  99                 local_irq_enable();
 100         }
 101 }
 102
 103 #ifdef CONFIG_HOTPLUG_CPU
 104 void arch_cpu_idle_dead(void)
 105 {
 106        cpu_die();
 107 }
 108 #endif
 109
 110 void machine_shutdown(void)
 111 {
 112 #ifdef CONFIG_SMP
 113         smp_send_stop();
 114 #endif
 115 }
 116
 117 void machine_halt(void)
 118 {
 119         machine_shutdown();
 120         while (1);
 121 }
 122
 123 void machine_power_off(void)
 124 {
 125         machine_shutdown();
 126         if (pm_power_off)
 127                 pm_power_off();
 128 }
 129
 130 void machine_restart(char *cmd)
 131 {
 132         machine_shutdown();
 133
 134         /* Disable interrupts first */
 135         local_irq_disable();
 136
 137         /* Now call the architecture specific reboot code. */
 138         if (arm_pm_restart)
 139                 arm_pm_restart(reboot_mode, cmd);
 140
 141         /*
 142          * Whoops - the architecture was unable to reboot.
 143          */
 144         printk("Reboot failed -- System halted\n");
 145         while (1);
 146 }
 147
 148 void __show_regs(struct pt_regs *regs)
 149 {
 150         int i, top_reg;
 151         u64 lr, sp;
 152
 153         if (compat_user_mode(regs)) {
 154                 lr = regs->compat_lr;
 155                 sp = regs->compat_sp;
 156                 top_reg = 12;
 157         } else {
 158                 lr = regs->regs[30];
 159                 sp = regs->sp;
 160                 top_reg = 29;
 161         }
 162
 163         show_regs_print_info(KERN_DEFAULT);
 164         print_symbol("PC is at %s\n", instruction_pointer(regs));
 165         print_symbol("LR is at %s\n", lr);
 166         printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 167                regs->pc, lr, regs->pstate);
 168         printk("sp : %016llx\n", sp);
 169         for (i = top_reg; i >= 0; i--) {
 170                 printk("x%-2d: %016llx ", i, regs->regs[i]);
 171                 if (i % 2 == 0)
 172                         printk("\n");
 173         }
 174         printk("\n");
 175 }
 176
 177 void show_regs(struct pt_regs * regs)
 178 {
 179         printk("\n");
 180         __show_regs(regs);
 181 }
 182
 183 /*
 184  * Free current thread data structures etc..
 185  */
 186 void exit_thread(void)
 187 {
 188 }
 189
 190 void flush_thread(void)
 191 {
 192         fpsimd_flush_thread();
 193         flush_ptrace_hw_breakpoint(current);
 194 }
 195
 196 void release_thread(struct task_struct *dead_task)
 197 {
 198 }
 199
 200 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 201 {
 202         fpsimd_save_state(&current->thread.fpsimd_state);
 203         *dst = *src;
 204         return 0;
 205 }
 206
 207 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 208
 209 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 210                 unsigned long stk_sz, struct task_struct *p)
 211 {
 212         struct pt_regs *childregs = task_pt_regs(p);
 213         unsigned long tls = p->thread.tp_value;
 214
 215         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 216
 217         if (likely(!(p->flags & PF_KTHREAD))) {
 218                 *childregs = *current_pt_regs();
 219                 childregs->regs[0] = 0;
 220                 if (is_compat_thread(task_thread_info(p))) {
 221                         if (stack_start)
 222                                 childregs->compat_sp = stack_start;
 223                 } else {
 224                         /*
 225                          * Read the current TLS pointer from tpidr_el0 as it may be
 226                          * out-of-sync with the saved value.
 227                          */
 228                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 229                         if (stack_start) {
 230                                 /* 16-byte aligned stack mandatory on AArch64 */
 231                                 if (stack_start & 15)
 232                                         return -EINVAL;
 233                                 childregs->sp = stack_start;
 234                         }
 235                 }
 236                 /*
 237                  * If a TLS pointer was passed to clone (4th argument), use it
 238                  * for the new thread.
 239                  */
 240                 if (clone_flags & CLONE_SETTLS)
 241                         tls = childregs->regs[3];
 242         } else {
 243                 memset(childregs, 0, sizeof(struct pt_regs));
 244                 childregs->pstate = PSR_MODE_EL1h;
 245                 p->thread.cpu_context.x19 = stack_start;
 246                 p->thread.cpu_context.x20 = stk_sz;
 247         }
 248         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 249         p->thread.cpu_context.sp = (unsigned long)childregs;
 250         p->thread.tp_value = tls;
 251
 252         ptrace_hw_copy_thread(p);
 253
 254         return 0;
 255 }
 256
 257 static void tls_thread_switch(struct task_struct *next)
 258 {
 259         unsigned long tpidr, tpidrro;
 260
 261         if (!is_compat_task()) {
 262                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 263                 current->thread.tp_value = tpidr;
 264         }
 265
 266         if (is_compat_thread(task_thread_info(next))) {
 267                 tpidr = 0;
 268                 tpidrro = next->thread.tp_value;
 269         } else {
 270                 tpidr = next->thread.tp_value;
 271                 tpidrro = 0;
 272         }
 273
 274         asm(
 275         "       msr     tpidr_el0, %0\n"
 276         "       msr     tpidrro_el0, %1"
 277         : : "r" (tpidr), "r" (tpidrro));
 278 }
 279
 280 /*
 281  * Thread switching.
 282  */
 283 struct task_struct *__switch_to(struct task_struct *prev,
 284                                 struct task_struct *next)
 285 {
 286         struct task_struct *last;
 287
 288         fpsimd_thread_switch(next);
 289         tls_thread_switch(next);
 290         hw_breakpoint_thread_switch(next);
 291         contextidr_thread_switch(next);
 292
 293         /*
 294          * Complete any pending TLB or cache maintenance on this CPU in case
 295          * the thread migrates to a different CPU.
 296          */
 297         dsb();
 298
 299         /* the actual thread switch */
 300         last = cpu_switch_to(prev, next);
 301
 302         return last;
 303 }
 304
 305 unsigned long get_wchan(struct task_struct *p)
 306 {
 307         struct stackframe frame;
 308         unsigned long stack_page;
 309         int count = 0;
 310         if (!p || p == current || p->state == TASK_RUNNING)
 311                 return 0;
 312
 313         frame.fp = thread_saved_fp(p);
 314         frame.sp = thread_saved_sp(p);
 315         frame.pc = thread_saved_pc(p);
 316         stack_page = (unsigned long)task_stack_page(p);
 317         do {
 318                 if (frame.sp < stack_page ||
 319                     frame.sp >= stack_page + THREAD_SIZE ||
 320                     unwind_frame(&frame))
 321                         return 0;
 322                 if (!in_sched_functions(frame.pc))
 323                         return frame.pc;
 324         } while (count ++ < 16);
 325         return 0;
 326 }
 327
 328 unsigned long arch_align_stack(unsigned long sp)
 329 {
 330         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 331                 sp -= get_random_int() & ~PAGE_MASK;
 332         return sp & ~0xf;
 333 }
 334
 335 static unsigned long randomize_base(unsigned long base)
 336 {
 337         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 338         return randomize_range(base, range_end, 0) ? : base;
 339 }
 340
 341 unsigned long arch_randomize_brk(struct mm_struct *mm)
 342 {
 343         return randomize_base(mm->brk);
 344 }
 345
 346 unsigned long randomize_et_dyn(unsigned long base)
 347 {
 348         return randomize_base(base);
 349 }