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         setup_restart();
  75         cpu_reset(addr);
  76 }
  77
  78 /*
  79  * Function pointers to optional machine specific functions
  80  */
  81 void (*pm_power_off)(void);
  82 EXPORT_SYMBOL_GPL(pm_power_off);
  83
  84 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
  85 EXPORT_SYMBOL_GPL(arm_pm_restart);
  86
  87 void arch_cpu_idle_prepare(void)
  88 {
  89         local_fiq_enable();
  90 }
  91
  92 /*
  93  * This is our default idle handler.
  94  */
  95 void arch_cpu_idle(void)
  96 {
  97         /*
  98          * This should do all the clock switching and wait for interrupt
  99          * tricks
 100          */
 101         cpu_do_idle();
 102         local_irq_enable();
 103 }
 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(reboot_mode, 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 void flush_thread(void)
 187 {
 188         fpsimd_flush_thread();
 189         flush_ptrace_hw_breakpoint(current);
 190 }
 191
 192 void release_thread(struct task_struct *dead_task)
 193 {
 194 }
 195
 196 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 197 {
 198         fpsimd_save_state(&current->thread.fpsimd_state);
 199         *dst = *src;
 200         return 0;
 201 }
 202
 203 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 204
 205 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 206                 unsigned long stk_sz, struct task_struct *p)
 207 {
 208         struct pt_regs *childregs = task_pt_regs(p);
 209         unsigned long tls = p->thread.tp_value;
 210
 211         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 212
 213         if (likely(!(p->flags & PF_KTHREAD))) {
 214                 *childregs = *current_pt_regs();
 215                 childregs->regs[0] = 0;
 216                 if (is_compat_thread(task_thread_info(p))) {
 217                         if (stack_start)
 218                                 childregs->compat_sp = stack_start;
 219                 } else {
 220                         /*
 221                          * Read the current TLS pointer from tpidr_el0 as it may be
 222                          * out-of-sync with the saved value.
 223                          */
 224                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 225                         if (stack_start) {
 226                                 /* 16-byte aligned stack mandatory on AArch64 */
 227                                 if (stack_start & 15)
 228                                         return -EINVAL;
 229                                 childregs->sp = stack_start;
 230                         }
 231                 }
 232                 /*
 233                  * If a TLS pointer was passed to clone (4th argument), use it
 234                  * for the new thread.
 235                  */
 236                 if (clone_flags & CLONE_SETTLS)
 237                         tls = childregs->regs[3];
 238         } else {
 239                 memset(childregs, 0, sizeof(struct pt_regs));
 240                 childregs->pstate = PSR_MODE_EL1h;
 241                 p->thread.cpu_context.x19 = stack_start;
 242                 p->thread.cpu_context.x20 = stk_sz;
 243         }
 244         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 245         p->thread.cpu_context.sp = (unsigned long)childregs;
 246         p->thread.tp_value = tls;
 247
 248         ptrace_hw_copy_thread(p);
 249
 250         return 0;
 251 }
 252
 253 static void tls_thread_switch(struct task_struct *next)
 254 {
 255         unsigned long tpidr, tpidrro;
 256
 257         if (!is_compat_task()) {
 258                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 259                 current->thread.tp_value = tpidr;
 260         }
 261
 262         if (is_compat_thread(task_thread_info(next))) {
 263                 tpidr = 0;
 264                 tpidrro = next->thread.tp_value;
 265         } else {
 266                 tpidr = next->thread.tp_value;
 267                 tpidrro = 0;
 268         }
 269
 270         asm(
 271         "       msr     tpidr_el0, %0\n"
 272         "       msr     tpidrro_el0, %1"
 273         : : "r" (tpidr), "r" (tpidrro));
 274 }
 275
 276 /*
 277  * Thread switching.
 278  */
 279 struct task_struct *__switch_to(struct task_struct *prev,
 280                                 struct task_struct *next)
 281 {
 282         struct task_struct *last;
 283
 284         fpsimd_thread_switch(next);
 285         tls_thread_switch(next);
 286         hw_breakpoint_thread_switch(next);
 287         contextidr_thread_switch(next);
 288
 289         /*
 290          * Complete any pending TLB or cache maintenance on this CPU in case
 291          * the thread migrates to a different CPU.
 292          */
 293         dsb();
 294
 295         /* the actual thread switch */
 296         last = cpu_switch_to(prev, next);
 297
 298         return last;
 299 }
 300
 301 unsigned long get_wchan(struct task_struct *p)
 302 {
 303         struct stackframe frame;
 304         int count = 0;
 305         if (!p || p == current || p->state == TASK_RUNNING)
 306                 return 0;
 307
 308         frame.fp = thread_saved_fp(p);
 309         frame.sp = thread_saved_sp(p);
 310         frame.pc = thread_saved_pc(p);
 311         do {
 312                 int ret = unwind_frame(&frame);
 313                 if (ret < 0)
 314                         return 0;
 315                 if (!in_sched_functions(frame.pc))
 316                         return frame.pc;
 317         } while (count ++ < 16);
 318         return 0;
 319 }
 320
 321 unsigned long arch_align_stack(unsigned long sp)
 322 {
 323         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 324                 sp -= get_random_int() & ~PAGE_MASK;
 325         return sp & ~0xf;
 326 }
 327
 328 static unsigned long randomize_base(unsigned long base)
 329 {
 330         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 331         return randomize_range(base, range_end, 0) ? : base;
 332 }
 333
 334 unsigned long arch_randomize_brk(struct mm_struct *mm)
 335 {
 336         return randomize_base(mm->brk);
 337 }
 338
 339 unsigned long randomize_et_dyn(unsigned long base)
 340 {
 341         return randomize_base(base);
 342 }