1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk}) 4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) 5 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 6 * Copyright 2003 PathScale, Inc. 7 */ 8 9 #include <linux/stddef.h> 10 #include <linux/err.h> 11 #include <linux/hardirq.h> 12 #include <linux/mm.h> 13 #include <linux/module.h> 14 #include <linux/personality.h> 15 #include <linux/proc_fs.h> 16 #include <linux/ptrace.h> 17 #include <linux/random.h> 18 #include <linux/slab.h> 19 #include <linux/sched.h> 20 #include <linux/sched/debug.h> 21 #include <linux/sched/task.h> 22 #include <linux/sched/task_stack.h> 23 #include <linux/seq_file.h> 24 #include <linux/tick.h> 25 #include <linux/threads.h> 26 #include <linux/tracehook.h> 27 #include <asm/current.h> 28 #include <asm/mmu_context.h> 29 #include <linux/uaccess.h> 30 #include <as-layout.h> 31 #include <kern_util.h> 32 #include <os.h> 33 #include <skas.h> 34 #include <linux/time-internal.h> 35 36 /* 37 * This is a per-cpu array. A processor only modifies its entry and it only 38 * cares about its entry, so it's OK if another processor is modifying its 39 * entry. 40 */ 41 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } }; 42 43 static inline int external_pid(void) 44 { 45 /* FIXME: Need to look up userspace_pid by cpu */ 46 return userspace_pid[0]; 47 } 48 49 int pid_to_processor_id(int pid) 50 { 51 int i; 52 53 for (i = 0; i < ncpus; i++) { 54 if (cpu_tasks[i].pid == pid) 55 return i; 56 } 57 return -1; 58 } 59 60 void free_stack(unsigned long stack, int order) 61 { 62 free_pages(stack, order); 63 } 64 65 unsigned long alloc_stack(int order, int atomic) 66 { 67 unsigned long page; 68 gfp_t flags = GFP_KERNEL; 69 70 if (atomic) 71 flags = GFP_ATOMIC; 72 page = __get_free_pages(flags, order); 73 74 return page; 75 } 76 77 static inline void set_current(struct task_struct *task) 78 { 79 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) 80 { external_pid(), task }); 81 } 82 83 extern void arch_switch_to(struct task_struct *to); 84 85 void *__switch_to(struct task_struct *from, struct task_struct *to) 86 { 87 to->thread.prev_sched = from; 88 set_current(to); 89 90 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf); 91 arch_switch_to(current); 92 93 return current->thread.prev_sched; 94 } 95 96 void interrupt_end(void) 97 { 98 struct pt_regs *regs = ¤t->thread.regs; 99 100 if (need_resched()) 101 schedule(); 102 if (test_thread_flag(TIF_SIGPENDING)) 103 do_signal(regs); 104 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) 105 tracehook_notify_resume(regs); 106 } 107 108 int get_current_pid(void) 109 { 110 return task_pid_nr(current); 111 } 112 113 /* 114 * This is called magically, by its address being stuffed in a jmp_buf 115 * and being longjmp-d to. 116 */ 117 void new_thread_handler(void) 118 { 119 int (*fn)(void *), n; 120 void *arg; 121 122 if (current->thread.prev_sched != NULL) 123 schedule_tail(current->thread.prev_sched); 124 current->thread.prev_sched = NULL; 125 126 fn = current->thread.request.u.thread.proc; 127 arg = current->thread.request.u.thread.arg; 128 129 /* 130 * callback returns only if the kernel thread execs a process 131 */ 132 n = fn(arg); 133 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); 134 } 135 136 /* Called magically, see new_thread_handler above */ 137 void fork_handler(void) 138 { 139 force_flush_all(); 140 141 schedule_tail(current->thread.prev_sched); 142 143 /* 144 * XXX: if interrupt_end() calls schedule, this call to 145 * arch_switch_to isn't needed. We could want to apply this to 146 * improve performance. -bb 147 */ 148 arch_switch_to(current); 149 150 current->thread.prev_sched = NULL; 151 152 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); 153 } 154 155 int copy_thread_tls(unsigned long clone_flags, unsigned long sp, 156 unsigned long arg, struct task_struct * p, unsigned long tls) 157 { 158 void (*handler)(void); 159 int kthread = current->flags & PF_KTHREAD; 160 int ret = 0; 161 162 p->thread = (struct thread_struct) INIT_THREAD; 163 164 if (!kthread) { 165 memcpy(&p->thread.regs.regs, current_pt_regs(), 166 sizeof(p->thread.regs.regs)); 167 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0); 168 if (sp != 0) 169 REGS_SP(p->thread.regs.regs.gp) = sp; 170 171 handler = fork_handler; 172 173 arch_copy_thread(¤t->thread.arch, &p->thread.arch); 174 } else { 175 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp); 176 p->thread.request.u.thread.proc = (int (*)(void *))sp; 177 p->thread.request.u.thread.arg = (void *)arg; 178 handler = new_thread_handler; 179 } 180 181 new_thread(task_stack_page(p), &p->thread.switch_buf, handler); 182 183 if (!kthread) { 184 clear_flushed_tls(p); 185 186 /* 187 * Set a new TLS for the child thread? 188 */ 189 if (clone_flags & CLONE_SETTLS) 190 ret = arch_set_tls(p, tls); 191 } 192 193 return ret; 194 } 195 196 void initial_thread_cb(void (*proc)(void *), void *arg) 197 { 198 int save_kmalloc_ok = kmalloc_ok; 199 200 kmalloc_ok = 0; 201 initial_thread_cb_skas(proc, arg); 202 kmalloc_ok = save_kmalloc_ok; 203 } 204 205 static void um_idle_sleep(void) 206 { 207 unsigned long long duration = UM_NSEC_PER_SEC; 208 209 if (time_travel_mode != TT_MODE_OFF) { 210 time_travel_sleep(duration); 211 } else { 212 os_idle_sleep(duration); 213 } 214 } 215 216 void arch_cpu_idle(void) 217 { 218 cpu_tasks[current_thread_info()->cpu].pid = os_getpid(); 219 um_idle_sleep(); 220 local_irq_enable(); 221 } 222 223 int __cant_sleep(void) { 224 return in_atomic() || irqs_disabled() || in_interrupt(); 225 /* Is in_interrupt() really needed? */ 226 } 227 228 int user_context(unsigned long sp) 229 { 230 unsigned long stack; 231 232 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER); 233 return stack != (unsigned long) current_thread_info(); 234 } 235 236 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end; 237 238 void do_uml_exitcalls(void) 239 { 240 exitcall_t *call; 241 242 call = &__uml_exitcall_end; 243 while (--call >= &__uml_exitcall_begin) 244 (*call)(); 245 } 246 247 char *uml_strdup(const char *string) 248 { 249 return kstrdup(string, GFP_KERNEL); 250 } 251 EXPORT_SYMBOL(uml_strdup); 252 253 int copy_to_user_proc(void __user *to, void *from, int size) 254 { 255 return copy_to_user(to, from, size); 256 } 257 258 int copy_from_user_proc(void *to, void __user *from, int size) 259 { 260 return copy_from_user(to, from, size); 261 } 262 263 int clear_user_proc(void __user *buf, int size) 264 { 265 return clear_user(buf, size); 266 } 267 268 int cpu(void) 269 { 270 return current_thread_info()->cpu; 271 } 272 273 static atomic_t using_sysemu = ATOMIC_INIT(0); 274 int sysemu_supported; 275 276 void set_using_sysemu(int value) 277 { 278 if (value > sysemu_supported) 279 return; 280 atomic_set(&using_sysemu, value); 281 } 282 283 int get_using_sysemu(void) 284 { 285 return atomic_read(&using_sysemu); 286 } 287 288 static int sysemu_proc_show(struct seq_file *m, void *v) 289 { 290 seq_printf(m, "%d\n", get_using_sysemu()); 291 return 0; 292 } 293 294 static int sysemu_proc_open(struct inode *inode, struct file *file) 295 { 296 return single_open(file, sysemu_proc_show, NULL); 297 } 298 299 static ssize_t sysemu_proc_write(struct file *file, const char __user *buf, 300 size_t count, loff_t *pos) 301 { 302 char tmp[2]; 303 304 if (copy_from_user(tmp, buf, 1)) 305 return -EFAULT; 306 307 if (tmp[0] >= '0' && tmp[0] <= '2') 308 set_using_sysemu(tmp[0] - '0'); 309 /* We use the first char, but pretend to write everything */ 310 return count; 311 } 312 313 static const struct proc_ops sysemu_proc_ops = { 314 .proc_open = sysemu_proc_open, 315 .proc_read = seq_read, 316 .proc_lseek = seq_lseek, 317 .proc_release = single_release, 318 .proc_write = sysemu_proc_write, 319 }; 320 321 int __init make_proc_sysemu(void) 322 { 323 struct proc_dir_entry *ent; 324 if (!sysemu_supported) 325 return 0; 326 327 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops); 328 329 if (ent == NULL) 330 { 331 printk(KERN_WARNING "Failed to register /proc/sysemu\n"); 332 return 0; 333 } 334 335 return 0; 336 } 337 338 late_initcall(make_proc_sysemu); 339 340 int singlestepping(void * t) 341 { 342 struct task_struct *task = t ? t : current; 343 344 if (!(task->ptrace & PT_DTRACE)) 345 return 0; 346 347 if (task->thread.singlestep_syscall) 348 return 1; 349 350 return 2; 351 } 352 353 /* 354 * Only x86 and x86_64 have an arch_align_stack(). 355 * All other arches have "#define arch_align_stack(x) (x)" 356 * in their asm/exec.h 357 * As this is included in UML from asm-um/system-generic.h, 358 * we can use it to behave as the subarch does. 359 */ 360 #ifndef arch_align_stack 361 unsigned long arch_align_stack(unsigned long sp) 362 { 363 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 364 sp -= get_random_int() % 8192; 365 return sp & ~0xf; 366 } 367 #endif 368 369 unsigned long get_wchan(struct task_struct *p) 370 { 371 unsigned long stack_page, sp, ip; 372 bool seen_sched = 0; 373 374 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING)) 375 return 0; 376 377 stack_page = (unsigned long) task_stack_page(p); 378 /* Bail if the process has no kernel stack for some reason */ 379 if (stack_page == 0) 380 return 0; 381 382 sp = p->thread.switch_buf->JB_SP; 383 /* 384 * Bail if the stack pointer is below the bottom of the kernel 385 * stack for some reason 386 */ 387 if (sp < stack_page) 388 return 0; 389 390 while (sp < stack_page + THREAD_SIZE) { 391 ip = *((unsigned long *) sp); 392 if (in_sched_functions(ip)) 393 /* Ignore everything until we're above the scheduler */ 394 seen_sched = 1; 395 else if (kernel_text_address(ip) && seen_sched) 396 return ip; 397 398 sp += sizeof(unsigned long); 399 } 400 401 return 0; 402 } 403 404 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu) 405 { 406 int cpu = current_thread_info()->cpu; 407 408 return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu); 409 } 410 411