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/compat.h>
  24 #include <linux/export.h>
  25 #include <linux/sched.h>
  26 #include <linux/kernel.h>
  27 #include <linux/mm.h>
  28 #include <linux/stddef.h>
  29 #include <linux/unistd.h>
  30 #include <linux/user.h>
  31 #include <linux/delay.h>
  32 #include <linux/reboot.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/kallsyms.h>
  35 #include <linux/init.h>
  36 #include <linux/cpu.h>
  37 #include <linux/cpuidle.h>
  38 #include <linux/elfcore.h>
  39 #include <linux/pm.h>
  40 #include <linux/tick.h>
  41 #include <linux/utsname.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/random.h>
  44 #include <linux/hw_breakpoint.h>
  45 #include <linux/personality.h>
  46 #include <linux/notifier.h>
  47
  48 #include <asm/compat.h>
  49 #include <asm/cacheflush.h>
  50 #include <asm/fpsimd.h>
  51 #include <asm/mmu_context.h>
  52 #include <asm/processor.h>
  53 #include <asm/stacktrace.h>
  54
  55 #ifdef CONFIG_CC_STACKPROTECTOR
  56 #include <linux/stackprotector.h>
  57 unsigned long __stack_chk_guard __read_mostly;
  58 EXPORT_SYMBOL(__stack_chk_guard);
  59 #endif
  60
  61 void soft_restart(unsigned long addr)
  62 {
  63         setup_mm_for_reboot();
  64         cpu_soft_restart(virt_to_phys(cpu_reset), addr);
  65         /* Should never get here */
  66         BUG();
  67 }
  68
  69 /*
  70  * Function pointers to optional machine specific functions
  71  */
  72 void (*pm_power_off)(void);
  73 EXPORT_SYMBOL_GPL(pm_power_off);
  74
  75 void (*arm_pm_restart)(char str, const char *cmd);
  76 EXPORT_SYMBOL_GPL(arm_pm_restart);
  77
  78 void arch_cpu_idle_prepare(void)
  79 {
  80         local_fiq_enable();
  81 }
  82
  83 /*
  84  * This is our default idle handler.
  85  */
  86 void arch_cpu_idle(void)
  87 {
  88         /*
  89          * This should do all the clock switching and wait for interrupt
  90          * tricks
  91          */
  92         if (cpuidle_idle_call()) {
  93                 cpu_do_idle();
  94                 local_irq_enable();
  95         }
  96 }
  97
  98 #ifdef CONFIG_HOTPLUG_CPU
  99 void arch_cpu_idle_dead(void)
 100 {
 101        cpu_die();
 102 }
 103 #endif
 104
 105 void machine_shutdown(void)
 106 {
 107 #ifdef CONFIG_SMP
 108         smp_send_stop();
 109 #endif
 110 }
 111
 112 void machine_halt(void)
 113 {
 114         machine_shutdown();
 115         while (1);
 116 }
 117
 118 void machine_power_off(void)
 119 {
 120         machine_shutdown();
 121         if (pm_power_off)
 122                 pm_power_off();
 123 }
 124
 125 void machine_restart(char *cmd)
 126 {
 127         machine_shutdown();
 128
 129         /* Disable interrupts first */
 130         local_irq_disable();
 131         local_fiq_disable();
 132
 133         /* Now call the architecture specific reboot code. */
 134         if (arm_pm_restart)
 135                 arm_pm_restart('h', cmd);
 136
 137         /*
 138          * Whoops - the architecture was unable to reboot.
 139          */
 140         printk("Reboot failed -- System halted\n");
 141         while (1);
 142 }
 143
 144 void __show_regs(struct pt_regs *regs)
 145 {
 146         int i, top_reg;
 147         u64 lr, sp;
 148
 149         if (compat_user_mode(regs)) {
 150                 lr = regs->compat_lr;
 151                 sp = regs->compat_sp;
 152                 top_reg = 12;
 153         } else {
 154                 lr = regs->regs[30];
 155                 sp = regs->sp;
 156                 top_reg = 29;
 157         }
 158
 159         show_regs_print_info(KERN_DEFAULT);
 160         print_symbol("PC is at %s\n", instruction_pointer(regs));
 161         print_symbol("LR is at %s\n", lr);
 162         printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 163                regs->pc, lr, regs->pstate);
 164         printk("sp : %016llx\n", sp);
 165         for (i = top_reg; i >= 0; i--) {
 166                 printk("x%-2d: %016llx ", i, regs->regs[i]);
 167                 if (i % 2 == 0)
 168                         printk("\n");
 169         }
 170         printk("\n");
 171 }
 172
 173 void show_regs(struct pt_regs * regs)
 174 {
 175         printk("\n");
 176         __show_regs(regs);
 177 }
 178
 179 /*
 180  * Free current thread data structures etc..
 181  */
 182 void exit_thread(void)
 183 {
 184 }
 185
 186 static void tls_thread_flush(void)
 187 {
 188         asm ("msr tpidr_el0, xzr");
 189
 190         if (is_compat_task()) {
 191                 current->thread.tp_value = 0;
 192
 193                 /*
 194                  * We need to ensure ordering between the shadow state and the
 195                  * hardware state, so that we don't corrupt the hardware state
 196                  * with a stale shadow state during context switch.
 197                  */
 198                 barrier();
 199                 asm ("msr tpidrro_el0, xzr");
 200         }
 201 }
 202
 203 void flush_thread(void)
 204 {
 205         fpsimd_flush_thread();
 206         tls_thread_flush();
 207         flush_ptrace_hw_breakpoint(current);
 208 }
 209
 210 void release_thread(struct task_struct *dead_task)
 211 {
 212 }
 213
 214 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 215 {
 216         fpsimd_save_state(&current->thread.fpsimd_state);
 217         *dst = *src;
 218         return 0;
 219 }
 220
 221 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 222
 223 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 224                 unsigned long stk_sz, struct task_struct *p)
 225 {
 226         struct pt_regs *childregs = task_pt_regs(p);
 227         unsigned long tls = p->thread.tp_value;
 228
 229         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 230
 231         if (likely(!(p->flags & PF_KTHREAD))) {
 232                 *childregs = *current_pt_regs();
 233                 childregs->regs[0] = 0;
 234                 if (is_compat_thread(task_thread_info(p))) {
 235                         if (stack_start)
 236                                 childregs->compat_sp = stack_start;
 237                 } else {
 238                         /*
 239                          * Read the current TLS pointer from tpidr_el0 as it may be
 240                          * out-of-sync with the saved value.
 241                          */
 242                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 243                         if (stack_start) {
 244                                 /* 16-byte aligned stack mandatory on AArch64 */
 245                                 if (stack_start & 15)
 246                                         return -EINVAL;
 247                                 childregs->sp = stack_start;
 248                         }
 249                 }
 250                 /*
 251                  * If a TLS pointer was passed to clone (4th argument), use it
 252                  * for the new thread.
 253                  */
 254                 if (clone_flags & CLONE_SETTLS)
 255                         tls = childregs->regs[3];
 256         } else {
 257                 memset(childregs, 0, sizeof(struct pt_regs));
 258                 childregs->pstate = PSR_MODE_EL1h;
 259                 p->thread.cpu_context.x19 = stack_start;
 260                 p->thread.cpu_context.x20 = stk_sz;
 261         }
 262         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 263         p->thread.cpu_context.sp = (unsigned long)childregs;
 264         p->thread.tp_value = tls;
 265
 266         ptrace_hw_copy_thread(p);
 267
 268         return 0;
 269 }
 270
 271 static void tls_thread_switch(struct task_struct *next)
 272 {
 273         unsigned long tpidr, tpidrro;
 274
 275         if (!is_compat_task()) {
 276                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 277                 current->thread.tp_value = tpidr;
 278         }
 279
 280         if (is_compat_thread(task_thread_info(next))) {
 281                 tpidr = 0;
 282                 tpidrro = next->thread.tp_value;
 283         } else {
 284                 tpidr = next->thread.tp_value;
 285                 tpidrro = 0;
 286         }
 287
 288         asm(
 289         "       msr     tpidr_el0, %0\n"
 290         "       msr     tpidrro_el0, %1"
 291         : : "r" (tpidr), "r" (tpidrro));
 292 }
 293
 294 /*
 295  * Thread switching.
 296  */
 297 struct task_struct *__switch_to(struct task_struct *prev,
 298                                 struct task_struct *next)
 299 {
 300         struct task_struct *last;
 301
 302         fpsimd_thread_switch(next);
 303         tls_thread_switch(next);
 304         hw_breakpoint_thread_switch(next);
 305         contextidr_thread_switch(next);
 306
 307         /*
 308          * Complete any pending TLB or cache maintenance on this CPU in case
 309          * the thread migrates to a different CPU.
 310          */
 311         dsb(ish);
 312
 313         /* the actual thread switch */
 314         last = cpu_switch_to(prev, next);
 315
 316         return last;
 317 }
 318
 319 unsigned long get_wchan(struct task_struct *p)
 320 {
 321         struct stackframe frame;
 322         unsigned long stack_page;
 323         int count = 0;
 324         if (!p || p == current || p->state == TASK_RUNNING)
 325                 return 0;
 326
 327         frame.fp = thread_saved_fp(p);
 328         frame.sp = thread_saved_sp(p);
 329         frame.pc = thread_saved_pc(p);
 330         stack_page = (unsigned long)task_stack_page(p);
 331         do {
 332                 if (frame.sp < stack_page ||
 333                     frame.sp >= stack_page + THREAD_SIZE ||
 334                     unwind_frame(&frame))
 335                         return 0;
 336                 if (!in_sched_functions(frame.pc))
 337                         return frame.pc;
 338         } while (count ++ < 16);
 339         return 0;
 340 }
 341
 342 unsigned long arch_align_stack(unsigned long sp)
 343 {
 344         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 345                 sp -= get_random_int() & ~PAGE_MASK;
 346         return sp & ~0xf;
 347 }
 348
 349 static unsigned long randomize_base(unsigned long base)
 350 {
 351         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 352         return randomize_range(base, range_end, 0) ? : base;
 353 }
 354
 355 unsigned long arch_randomize_brk(struct mm_struct *mm)
 356 {
 357         return randomize_base(mm->brk);
 358 }
 359
 360 unsigned long randomize_et_dyn(unsigned long base)
 361 {
 362         return randomize_base(base);
 363 }