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/processor.h> 49 #include <asm/stacktrace.h> 50 #include <asm/fpsimd.h> 51 52 static void setup_restart(void) 53 { 54 /* 55 * Tell the mm system that we are going to reboot - 56 * we may need it to insert some 1:1 mappings so that 57 * soft boot works. 58 */ 59 setup_mm_for_reboot(); 60 61 /* Clean and invalidate caches */ 62 flush_cache_all(); 63 64 /* Turn D-cache off */ 65 cpu_cache_off(); 66 67 /* Push out any further dirty data, and ensure cache is empty */ 68 flush_cache_all(); 69 } 70 71 void soft_restart(unsigned long addr) 72 { 73 setup_restart(); 74 cpu_reset(addr); 75 } 76 77 /* 78 * Function pointers to optional machine specific functions 79 */ 80 void (*pm_power_off)(void); 81 EXPORT_SYMBOL_GPL(pm_power_off); 82 83 void (*pm_restart)(const char *cmd); 84 EXPORT_SYMBOL_GPL(pm_restart); 85 86 87 /* 88 * This is our default idle handler. 89 */ 90 static void default_idle(void) 91 { 92 /* 93 * This should do all the clock switching and wait for interrupt 94 * tricks 95 */ 96 cpu_do_idle(); 97 local_irq_enable(); 98 } 99 100 void (*pm_idle)(void) = default_idle; 101 EXPORT_SYMBOL_GPL(pm_idle); 102 103 /* 104 * The idle thread, has rather strange semantics for calling pm_idle, 105 * but this is what x86 does and we need to do the same, so that 106 * things like cpuidle get called in the same way. The only difference 107 * is that we always respect 'hlt_counter' to prevent low power idle. 108 */ 109 void cpu_idle(void) 110 { 111 local_fiq_enable(); 112 113 /* endless idle loop with no priority at all */ 114 while (1) { 115 tick_nohz_idle_enter(); 116 rcu_idle_enter(); 117 while (!need_resched()) { 118 /* 119 * We need to disable interrupts here to ensure 120 * we don't miss a wakeup call. 121 */ 122 local_irq_disable(); 123 if (!need_resched()) { 124 stop_critical_timings(); 125 pm_idle(); 126 start_critical_timings(); 127 /* 128 * pm_idle functions should always return 129 * with IRQs enabled. 130 */ 131 WARN_ON(irqs_disabled()); 132 } else { 133 local_irq_enable(); 134 } 135 } 136 rcu_idle_exit(); 137 tick_nohz_idle_exit(); 138 schedule_preempt_disabled(); 139 } 140 } 141 142 void machine_shutdown(void) 143 { 144 #ifdef CONFIG_SMP 145 smp_send_stop(); 146 #endif 147 } 148 149 void machine_halt(void) 150 { 151 machine_shutdown(); 152 while (1); 153 } 154 155 void machine_power_off(void) 156 { 157 machine_shutdown(); 158 if (pm_power_off) 159 pm_power_off(); 160 } 161 162 void machine_restart(char *cmd) 163 { 164 machine_shutdown(); 165 166 /* Disable interrupts first */ 167 local_irq_disable(); 168 local_fiq_disable(); 169 170 /* Now call the architecture specific reboot code. */ 171 if (pm_restart) 172 pm_restart(cmd); 173 174 /* 175 * Whoops - the architecture was unable to reboot. 176 */ 177 printk("Reboot failed -- System halted\n"); 178 while (1); 179 } 180 181 void __show_regs(struct pt_regs *regs) 182 { 183 int i; 184 185 printk("CPU: %d %s (%s %.*s)\n", 186 raw_smp_processor_id(), print_tainted(), 187 init_utsname()->release, 188 (int)strcspn(init_utsname()->version, " "), 189 init_utsname()->version); 190 print_symbol("PC is at %s\n", instruction_pointer(regs)); 191 print_symbol("LR is at %s\n", regs->regs[30]); 192 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", 193 regs->pc, regs->regs[30], regs->pstate); 194 printk("sp : %016llx\n", regs->sp); 195 for (i = 29; i >= 0; i--) { 196 printk("x%-2d: %016llx ", i, regs->regs[i]); 197 if (i % 2 == 0) 198 printk("\n"); 199 } 200 printk("\n"); 201 } 202 203 void show_regs(struct pt_regs * regs) 204 { 205 printk("\n"); 206 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 207 __show_regs(regs); 208 } 209 210 /* 211 * Free current thread data structures etc.. 212 */ 213 void exit_thread(void) 214 { 215 } 216 217 void flush_thread(void) 218 { 219 fpsimd_flush_thread(); 220 flush_ptrace_hw_breakpoint(current); 221 } 222 223 void release_thread(struct task_struct *dead_task) 224 { 225 } 226 227 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 228 { 229 fpsimd_save_state(¤t->thread.fpsimd_state); 230 *dst = *src; 231 return 0; 232 } 233 234 asmlinkage void ret_from_fork(void) asm("ret_from_fork"); 235 236 int copy_thread(unsigned long clone_flags, unsigned long stack_start, 237 unsigned long stk_sz, struct task_struct *p) 238 { 239 struct pt_regs *childregs = task_pt_regs(p); 240 unsigned long tls = p->thread.tp_value; 241 242 memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); 243 244 if (likely(!(p->flags & PF_KTHREAD))) { 245 *childregs = *current_pt_regs(); 246 childregs->regs[0] = 0; 247 if (is_compat_thread(task_thread_info(p))) { 248 if (stack_start) 249 childregs->compat_sp = stack_start; 250 } else { 251 /* 252 * Read the current TLS pointer from tpidr_el0 as it may be 253 * out-of-sync with the saved value. 254 */ 255 asm("mrs %0, tpidr_el0" : "=r" (tls)); 256 if (stack_start) { 257 /* 16-byte aligned stack mandatory on AArch64 */ 258 if (stack_start & 15) 259 return -EINVAL; 260 childregs->sp = stack_start; 261 } 262 } 263 /* 264 * If a TLS pointer was passed to clone (4th argument), use it 265 * for the new thread. 266 */ 267 if (clone_flags & CLONE_SETTLS) 268 tls = childregs->regs[3]; 269 } else { 270 memset(childregs, 0, sizeof(struct pt_regs)); 271 childregs->pstate = PSR_MODE_EL1h; 272 p->thread.cpu_context.x19 = stack_start; 273 p->thread.cpu_context.x20 = stk_sz; 274 } 275 p->thread.cpu_context.pc = (unsigned long)ret_from_fork; 276 p->thread.cpu_context.sp = (unsigned long)childregs; 277 p->thread.tp_value = tls; 278 279 ptrace_hw_copy_thread(p); 280 281 return 0; 282 } 283 284 static void tls_thread_switch(struct task_struct *next) 285 { 286 unsigned long tpidr, tpidrro; 287 288 if (!is_compat_task()) { 289 asm("mrs %0, tpidr_el0" : "=r" (tpidr)); 290 current->thread.tp_value = tpidr; 291 } 292 293 if (is_compat_thread(task_thread_info(next))) { 294 tpidr = 0; 295 tpidrro = next->thread.tp_value; 296 } else { 297 tpidr = next->thread.tp_value; 298 tpidrro = 0; 299 } 300 301 asm( 302 " msr tpidr_el0, %0\n" 303 " msr tpidrro_el0, %1" 304 : : "r" (tpidr), "r" (tpidrro)); 305 } 306 307 /* 308 * Thread switching. 309 */ 310 struct task_struct *__switch_to(struct task_struct *prev, 311 struct task_struct *next) 312 { 313 struct task_struct *last; 314 315 fpsimd_thread_switch(next); 316 tls_thread_switch(next); 317 hw_breakpoint_thread_switch(next); 318 319 /* the actual thread switch */ 320 last = cpu_switch_to(prev, next); 321 322 return last; 323 } 324 325 unsigned long get_wchan(struct task_struct *p) 326 { 327 struct stackframe frame; 328 int count = 0; 329 if (!p || p == current || p->state == TASK_RUNNING) 330 return 0; 331 332 frame.fp = thread_saved_fp(p); 333 frame.sp = thread_saved_sp(p); 334 frame.pc = thread_saved_pc(p); 335 do { 336 int ret = unwind_frame(&frame); 337 if (ret < 0) 338 return 0; 339 if (!in_sched_functions(frame.pc)) 340 return frame.pc; 341 } while (count ++ < 16); 342 return 0; 343 } 344 345 unsigned long arch_align_stack(unsigned long sp) 346 { 347 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 348 sp -= get_random_int() & ~PAGE_MASK; 349 return sp & ~0xf; 350 } 351 352 static unsigned long randomize_base(unsigned long base) 353 { 354 unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1; 355 return randomize_range(base, range_end, 0) ? : base; 356 } 357 358 unsigned long arch_randomize_brk(struct mm_struct *mm) 359 { 360 return randomize_base(mm->brk); 361 } 362 363 unsigned long randomize_et_dyn(unsigned long base) 364 { 365 return randomize_base(base); 366 } 367