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 typedef void (*phys_reset_t)(unsigned long); 75 phys_reset_t phys_reset; 76 77 setup_restart(); 78 79 /* Switch to the identity mapping */ 80 phys_reset = (phys_reset_t)virt_to_phys(cpu_reset); 81 phys_reset(addr); 82 83 /* Should never get here */ 84 BUG(); 85 } 86 87 /* 88 * Function pointers to optional machine specific functions 89 */ 90 void (*pm_power_off)(void); 91 EXPORT_SYMBOL_GPL(pm_power_off); 92 93 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); 94 EXPORT_SYMBOL_GPL(arm_pm_restart); 95 96 /* 97 * This is our default idle handler. 98 */ 99 void arch_cpu_idle(void) 100 { 101 /* 102 * This should do all the clock switching and wait for interrupt 103 * tricks 104 */ 105 cpu_do_idle(); 106 local_irq_enable(); 107 } 108 109 #ifdef CONFIG_HOTPLUG_CPU 110 void arch_cpu_idle_dead(void) 111 { 112 cpu_die(); 113 } 114 #endif 115 116 void machine_shutdown(void) 117 { 118 #ifdef CONFIG_SMP 119 smp_send_stop(); 120 #endif 121 } 122 123 void machine_halt(void) 124 { 125 machine_shutdown(); 126 while (1); 127 } 128 129 void machine_power_off(void) 130 { 131 machine_shutdown(); 132 if (pm_power_off) 133 pm_power_off(); 134 } 135 136 void machine_restart(char *cmd) 137 { 138 machine_shutdown(); 139 140 /* Disable interrupts first */ 141 local_irq_disable(); 142 143 /* Now call the architecture specific reboot code. */ 144 if (arm_pm_restart) 145 arm_pm_restart(reboot_mode, cmd); 146 147 /* 148 * Whoops - the architecture was unable to reboot. 149 */ 150 printk("Reboot failed -- System halted\n"); 151 while (1); 152 } 153 154 void __show_regs(struct pt_regs *regs) 155 { 156 int i, top_reg; 157 u64 lr, sp; 158 159 if (compat_user_mode(regs)) { 160 lr = regs->compat_lr; 161 sp = regs->compat_sp; 162 top_reg = 12; 163 } else { 164 lr = regs->regs[30]; 165 sp = regs->sp; 166 top_reg = 29; 167 } 168 169 show_regs_print_info(KERN_DEFAULT); 170 print_symbol("PC is at %s\n", instruction_pointer(regs)); 171 print_symbol("LR is at %s\n", lr); 172 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", 173 regs->pc, lr, regs->pstate); 174 printk("sp : %016llx\n", sp); 175 for (i = top_reg; i >= 0; i--) { 176 printk("x%-2d: %016llx ", i, regs->regs[i]); 177 if (i % 2 == 0) 178 printk("\n"); 179 } 180 printk("\n"); 181 } 182 183 void show_regs(struct pt_regs * regs) 184 { 185 printk("\n"); 186 __show_regs(regs); 187 } 188 189 /* 190 * Free current thread data structures etc.. 191 */ 192 void exit_thread(void) 193 { 194 } 195 196 void flush_thread(void) 197 { 198 fpsimd_flush_thread(); 199 flush_ptrace_hw_breakpoint(current); 200 } 201 202 void release_thread(struct task_struct *dead_task) 203 { 204 } 205 206 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 207 { 208 fpsimd_save_state(¤t->thread.fpsimd_state); 209 *dst = *src; 210 return 0; 211 } 212 213 asmlinkage void ret_from_fork(void) asm("ret_from_fork"); 214 215 int copy_thread(unsigned long clone_flags, unsigned long stack_start, 216 unsigned long stk_sz, struct task_struct *p) 217 { 218 struct pt_regs *childregs = task_pt_regs(p); 219 unsigned long tls = p->thread.tp_value; 220 221 memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); 222 223 if (likely(!(p->flags & PF_KTHREAD))) { 224 *childregs = *current_pt_regs(); 225 childregs->regs[0] = 0; 226 if (is_compat_thread(task_thread_info(p))) { 227 if (stack_start) 228 childregs->compat_sp = stack_start; 229 } else { 230 /* 231 * Read the current TLS pointer from tpidr_el0 as it may be 232 * out-of-sync with the saved value. 233 */ 234 asm("mrs %0, tpidr_el0" : "=r" (tls)); 235 if (stack_start) { 236 /* 16-byte aligned stack mandatory on AArch64 */ 237 if (stack_start & 15) 238 return -EINVAL; 239 childregs->sp = stack_start; 240 } 241 } 242 /* 243 * If a TLS pointer was passed to clone (4th argument), use it 244 * for the new thread. 245 */ 246 if (clone_flags & CLONE_SETTLS) 247 tls = childregs->regs[3]; 248 } else { 249 memset(childregs, 0, sizeof(struct pt_regs)); 250 childregs->pstate = PSR_MODE_EL1h; 251 p->thread.cpu_context.x19 = stack_start; 252 p->thread.cpu_context.x20 = stk_sz; 253 } 254 p->thread.cpu_context.pc = (unsigned long)ret_from_fork; 255 p->thread.cpu_context.sp = (unsigned long)childregs; 256 p->thread.tp_value = tls; 257 258 ptrace_hw_copy_thread(p); 259 260 return 0; 261 } 262 263 static void tls_thread_switch(struct task_struct *next) 264 { 265 unsigned long tpidr, tpidrro; 266 267 if (!is_compat_task()) { 268 asm("mrs %0, tpidr_el0" : "=r" (tpidr)); 269 current->thread.tp_value = tpidr; 270 } 271 272 if (is_compat_thread(task_thread_info(next))) { 273 tpidr = 0; 274 tpidrro = next->thread.tp_value; 275 } else { 276 tpidr = next->thread.tp_value; 277 tpidrro = 0; 278 } 279 280 asm( 281 " msr tpidr_el0, %0\n" 282 " msr tpidrro_el0, %1" 283 : : "r" (tpidr), "r" (tpidrro)); 284 } 285 286 /* 287 * Thread switching. 288 */ 289 struct task_struct *__switch_to(struct task_struct *prev, 290 struct task_struct *next) 291 { 292 struct task_struct *last; 293 294 fpsimd_thread_switch(next); 295 tls_thread_switch(next); 296 hw_breakpoint_thread_switch(next); 297 contextidr_thread_switch(next); 298 299 /* 300 * Complete any pending TLB or cache maintenance on this CPU in case 301 * the thread migrates to a different CPU. 302 */ 303 dsb(); 304 305 /* the actual thread switch */ 306 last = cpu_switch_to(prev, next); 307 308 return last; 309 } 310 311 unsigned long get_wchan(struct task_struct *p) 312 { 313 struct stackframe frame; 314 unsigned long stack_page; 315 int count = 0; 316 if (!p || p == current || p->state == TASK_RUNNING) 317 return 0; 318 319 frame.fp = thread_saved_fp(p); 320 frame.sp = thread_saved_sp(p); 321 frame.pc = thread_saved_pc(p); 322 stack_page = (unsigned long)task_stack_page(p); 323 do { 324 if (frame.sp < stack_page || 325 frame.sp >= stack_page + THREAD_SIZE || 326 unwind_frame(&frame)) 327 return 0; 328 if (!in_sched_functions(frame.pc)) 329 return frame.pc; 330 } while (count ++ < 16); 331 return 0; 332 } 333 334 unsigned long arch_align_stack(unsigned long sp) 335 { 336 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 337 sp -= get_random_int() & ~PAGE_MASK; 338 return sp & ~0xf; 339 } 340 341 static unsigned long randomize_base(unsigned long base) 342 { 343 unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1; 344 return randomize_range(base, range_end, 0) ? : base; 345 } 346 347 unsigned long arch_randomize_brk(struct mm_struct *mm) 348 { 349 return randomize_base(mm->brk); 350 } 351 352 unsigned long randomize_et_dyn(unsigned long base) 353 { 354 return randomize_base(base); 355 } 356