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)(char str, 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('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;
 147
 148         show_regs_print_info(KERN_DEFAULT);
 149         print_symbol("PC is at %s\n", instruction_pointer(regs));
 150         print_symbol("LR is at %s\n", regs->regs[30]);
 151         printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 152                regs->pc, regs->regs[30], regs->pstate);
 153         printk("sp : %016llx\n", regs->sp);
 154         for (i = 29; i >= 0; i--) {
 155                 printk("x%-2d: %016llx ", i, regs->regs[i]);
 156                 if (i % 2 == 0)
 157                         printk("\n");
 158         }
 159         printk("\n");
 160 }
 161
 162 void show_regs(struct pt_regs * regs)
 163 {
 164         printk("\n");
 165         __show_regs(regs);
 166 }
 167
 168 /*
 169  * Free current thread data structures etc..
 170  */
 171 void exit_thread(void)
 172 {
 173 }
 174
 175 void flush_thread(void)
 176 {
 177         fpsimd_flush_thread();
 178         flush_ptrace_hw_breakpoint(current);
 179 }
 180
 181 void release_thread(struct task_struct *dead_task)
 182 {
 183 }
 184
 185 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 186 {
 187         fpsimd_save_state(&current->thread.fpsimd_state);
 188         *dst = *src;
 189         return 0;
 190 }
 191
 192 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 193
 194 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 195                 unsigned long stk_sz, struct task_struct *p)
 196 {
 197         struct pt_regs *childregs = task_pt_regs(p);
 198         unsigned long tls = p->thread.tp_value;
 199
 200         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 201
 202         if (likely(!(p->flags & PF_KTHREAD))) {
 203                 *childregs = *current_pt_regs();
 204                 childregs->regs[0] = 0;
 205                 if (is_compat_thread(task_thread_info(p))) {
 206                         if (stack_start)
 207                                 childregs->compat_sp = stack_start;
 208                 } else {
 209                         /*
 210                          * Read the current TLS pointer from tpidr_el0 as it may be
 211                          * out-of-sync with the saved value.
 212                          */
 213                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 214                         if (stack_start) {
 215                                 /* 16-byte aligned stack mandatory on AArch64 */
 216                                 if (stack_start & 15)
 217                                         return -EINVAL;
 218                                 childregs->sp = stack_start;
 219                         }
 220                 }
 221                 /*
 222                  * If a TLS pointer was passed to clone (4th argument), use it
 223                  * for the new thread.
 224                  */
 225                 if (clone_flags & CLONE_SETTLS)
 226                         tls = childregs->regs[3];
 227         } else {
 228                 memset(childregs, 0, sizeof(struct pt_regs));
 229                 childregs->pstate = PSR_MODE_EL1h;
 230                 p->thread.cpu_context.x19 = stack_start;
 231                 p->thread.cpu_context.x20 = stk_sz;
 232         }
 233         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 234         p->thread.cpu_context.sp = (unsigned long)childregs;
 235         p->thread.tp_value = tls;
 236
 237         ptrace_hw_copy_thread(p);
 238
 239         return 0;
 240 }
 241
 242 static void tls_thread_switch(struct task_struct *next)
 243 {
 244         unsigned long tpidr, tpidrro;
 245
 246         if (!is_compat_task()) {
 247                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 248                 current->thread.tp_value = tpidr;
 249         }
 250
 251         if (is_compat_thread(task_thread_info(next))) {
 252                 tpidr = 0;
 253                 tpidrro = next->thread.tp_value;
 254         } else {
 255                 tpidr = next->thread.tp_value;
 256                 tpidrro = 0;
 257         }
 258
 259         asm(
 260         "       msr     tpidr_el0, %0\n"
 261         "       msr     tpidrro_el0, %1"
 262         : : "r" (tpidr), "r" (tpidrro));
 263 }
 264
 265 /*
 266  * Thread switching.
 267  */
 268 struct task_struct *__switch_to(struct task_struct *prev,
 269                                 struct task_struct *next)
 270 {
 271         struct task_struct *last;
 272
 273         fpsimd_thread_switch(next);
 274         tls_thread_switch(next);
 275         hw_breakpoint_thread_switch(next);
 276         contextidr_thread_switch(next);
 277
 278         /*
 279          * Complete any pending TLB or cache maintenance on this CPU in case
 280          * the thread migrates to a different CPU.
 281          */
 282         dsb();
 283
 284         /* the actual thread switch */
 285         last = cpu_switch_to(prev, next);
 286
 287         return last;
 288 }
 289
 290 unsigned long get_wchan(struct task_struct *p)
 291 {
 292         struct stackframe frame;
 293         int count = 0;
 294         if (!p || p == current || p->state == TASK_RUNNING)
 295                 return 0;
 296
 297         frame.fp = thread_saved_fp(p);
 298         frame.sp = thread_saved_sp(p);
 299         frame.pc = thread_saved_pc(p);
 300         do {
 301                 int ret = unwind_frame(&frame);
 302                 if (ret < 0)
 303                         return 0;
 304                 if (!in_sched_functions(frame.pc))
 305                         return frame.pc;
 306         } while (count ++ < 16);
 307         return 0;
 308 }
 309
 310 unsigned long arch_align_stack(unsigned long sp)
 311 {
 312         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 313                 sp -= get_random_int() & ~PAGE_MASK;
 314         return sp & ~0xf;
 315 }
 316
 317 static unsigned long randomize_base(unsigned long base)
 318 {
 319         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 320         return randomize_range(base, range_end, 0) ? : base;
 321 }
 322
 323 unsigned long arch_randomize_brk(struct mm_struct *mm)
 324 {
 325         return randomize_base(mm->brk);
 326 }
 327
 328 unsigned long randomize_et_dyn(unsigned long base)
 329 {
 330         return randomize_base(base);
 331 }