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 (*pm_restart)(const char *cmd);
  85 EXPORT_SYMBOL_GPL(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 (pm_restart)
 135                 pm_restart(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         printk("CPU: %d    %s  (%s %.*s)\n",
 149                 raw_smp_processor_id(), print_tainted(),
 150                 init_utsname()->release,
 151                 (int)strcspn(init_utsname()->version, " "),
 152                 init_utsname()->version);
 153         print_symbol("PC is at %s\n", instruction_pointer(regs));
 154         print_symbol("LR is at %s\n", regs->regs[30]);
 155         printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 156                regs->pc, regs->regs[30], regs->pstate);
 157         printk("sp : %016llx\n", regs->sp);
 158         for (i = 29; i >= 0; i--) {
 159                 printk("x%-2d: %016llx ", i, regs->regs[i]);
 160                 if (i % 2 == 0)
 161                         printk("\n");
 162         }
 163         printk("\n");
 164 }
 165
 166 void show_regs(struct pt_regs * regs)
 167 {
 168         printk("\n");
 169         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 170         __show_regs(regs);
 171 }
 172
 173 /*
 174  * Free current thread data structures etc..
 175  */
 176 void exit_thread(void)
 177 {
 178 }
 179
 180 void flush_thread(void)
 181 {
 182         fpsimd_flush_thread();
 183         flush_ptrace_hw_breakpoint(current);
 184 }
 185
 186 void release_thread(struct task_struct *dead_task)
 187 {
 188 }
 189
 190 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 191 {
 192         fpsimd_save_state(&current->thread.fpsimd_state);
 193         *dst = *src;
 194         return 0;
 195 }
 196
 197 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 198
 199 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 200                 unsigned long stk_sz, struct task_struct *p)
 201 {
 202         struct pt_regs *childregs = task_pt_regs(p);
 203         unsigned long tls = p->thread.tp_value;
 204
 205         memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 206
 207         if (likely(!(p->flags & PF_KTHREAD))) {
 208                 *childregs = *current_pt_regs();
 209                 childregs->regs[0] = 0;
 210                 if (is_compat_thread(task_thread_info(p))) {
 211                         if (stack_start)
 212                                 childregs->compat_sp = stack_start;
 213                 } else {
 214                         /*
 215                          * Read the current TLS pointer from tpidr_el0 as it may be
 216                          * out-of-sync with the saved value.
 217                          */
 218                         asm("mrs %0, tpidr_el0" : "=r" (tls));
 219                         if (stack_start) {
 220                                 /* 16-byte aligned stack mandatory on AArch64 */
 221                                 if (stack_start & 15)
 222                                         return -EINVAL;
 223                                 childregs->sp = stack_start;
 224                         }
 225                 }
 226                 /*
 227                  * If a TLS pointer was passed to clone (4th argument), use it
 228                  * for the new thread.
 229                  */
 230                 if (clone_flags & CLONE_SETTLS)
 231                         tls = childregs->regs[3];
 232         } else {
 233                 memset(childregs, 0, sizeof(struct pt_regs));
 234                 childregs->pstate = PSR_MODE_EL1h;
 235                 p->thread.cpu_context.x19 = stack_start;
 236                 p->thread.cpu_context.x20 = stk_sz;
 237         }
 238         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 239         p->thread.cpu_context.sp = (unsigned long)childregs;
 240         p->thread.tp_value = tls;
 241
 242         ptrace_hw_copy_thread(p);
 243
 244         return 0;
 245 }
 246
 247 static void tls_thread_switch(struct task_struct *next)
 248 {
 249         unsigned long tpidr, tpidrro;
 250
 251         if (!is_compat_task()) {
 252                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 253                 current->thread.tp_value = tpidr;
 254         }
 255
 256         if (is_compat_thread(task_thread_info(next))) {
 257                 tpidr = 0;
 258                 tpidrro = next->thread.tp_value;
 259         } else {
 260                 tpidr = next->thread.tp_value;
 261                 tpidrro = 0;
 262         }
 263
 264         asm(
 265         "       msr     tpidr_el0, %0\n"
 266         "       msr     tpidrro_el0, %1"
 267         : : "r" (tpidr), "r" (tpidrro));
 268 }
 269
 270 /*
 271  * Thread switching.
 272  */
 273 struct task_struct *__switch_to(struct task_struct *prev,
 274                                 struct task_struct *next)
 275 {
 276         struct task_struct *last;
 277
 278         fpsimd_thread_switch(next);
 279         tls_thread_switch(next);
 280         hw_breakpoint_thread_switch(next);
 281         contextidr_thread_switch(next);
 282
 283         /*
 284          * Complete any pending TLB or cache maintenance on this CPU in case
 285          * the thread migrates to a different CPU.
 286          */
 287         dsb();
 288
 289         /* the actual thread switch */
 290         last = cpu_switch_to(prev, next);
 291
 292         return last;
 293 }
 294
 295 unsigned long get_wchan(struct task_struct *p)
 296 {
 297         struct stackframe frame;
 298         int count = 0;
 299         if (!p || p == current || p->state == TASK_RUNNING)
 300                 return 0;
 301
 302         frame.fp = thread_saved_fp(p);
 303         frame.sp = thread_saved_sp(p);
 304         frame.pc = thread_saved_pc(p);
 305         do {
 306                 int ret = unwind_frame(&frame);
 307                 if (ret < 0)
 308                         return 0;
 309                 if (!in_sched_functions(frame.pc))
 310                         return frame.pc;
 311         } while (count ++ < 16);
 312         return 0;
 313 }
 314
 315 unsigned long arch_align_stack(unsigned long sp)
 316 {
 317         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 318                 sp -= get_random_int() & ~PAGE_MASK;
 319         return sp & ~0xf;
 320 }
 321
 322 static unsigned long randomize_base(unsigned long base)
 323 {
 324         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 325         return randomize_range(base, range_end, 0) ? : base;
 326 }
 327
 328 unsigned long arch_randomize_brk(struct mm_struct *mm)
 329 {
 330         return randomize_base(mm->brk);
 331 }
 332
 333 unsigned long randomize_et_dyn(unsigned long base)
 334 {
 335         return randomize_base(base);
 336 }