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/resume_user_mode.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 <registers.h> 35 #include <linux/time-internal.h> 36 #include <linux/elfcore.h> 37 38 /* 39 * This is a per-cpu array. A processor only modifies its entry and it only 40 * cares about its entry, so it's OK if another processor is modifying its 41 * entry. 42 */ 43 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } }; 44 45 static inline int external_pid(void) 46 { 47 /* FIXME: Need to look up userspace_pid by cpu */ 48 return userspace_pid[0]; 49 } 50 51 int pid_to_processor_id(int pid) 52 { 53 int i; 54 55 for (i = 0; i < ncpus; i++) { 56 if (cpu_tasks[i].pid == pid) 57 return i; 58 } 59 return -1; 60 } 61 62 void free_stack(unsigned long stack, int order) 63 { 64 free_pages(stack, order); 65 } 66 67 unsigned long alloc_stack(int order, int atomic) 68 { 69 unsigned long page; 70 gfp_t flags = GFP_KERNEL; 71 72 if (atomic) 73 flags = GFP_ATOMIC; 74 page = __get_free_pages(flags, order); 75 76 return page; 77 } 78 79 static inline void set_current(struct task_struct *task) 80 { 81 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) 82 { external_pid(), task }); 83 } 84 85 extern void arch_switch_to(struct task_struct *to); 86 87 void *__switch_to(struct task_struct *from, struct task_struct *to) 88 { 89 to->thread.prev_sched = from; 90 set_current(to); 91 92 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf); 93 arch_switch_to(current); 94 95 return current->thread.prev_sched; 96 } 97 98 void interrupt_end(void) 99 { 100 struct pt_regs *regs = ¤t->thread.regs; 101 102 if (need_resched()) 103 schedule(); 104 if (test_thread_flag(TIF_SIGPENDING) || 105 test_thread_flag(TIF_NOTIFY_SIGNAL)) 106 do_signal(regs); 107 if (test_thread_flag(TIF_NOTIFY_RESUME)) 108 resume_user_mode_work(regs); 109 } 110 111 int get_current_pid(void) 112 { 113 return task_pid_nr(current); 114 } 115 116 /* 117 * This is called magically, by its address being stuffed in a jmp_buf 118 * and being longjmp-d to. 119 */ 120 void new_thread_handler(void) 121 { 122 int (*fn)(void *), n; 123 void *arg; 124 125 if (current->thread.prev_sched != NULL) 126 schedule_tail(current->thread.prev_sched); 127 current->thread.prev_sched = NULL; 128 129 fn = current->thread.request.u.thread.proc; 130 arg = current->thread.request.u.thread.arg; 131 132 /* 133 * callback returns only if the kernel thread execs a process 134 */ 135 n = fn(arg); 136 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); 137 } 138 139 /* Called magically, see new_thread_handler above */ 140 void fork_handler(void) 141 { 142 force_flush_all(); 143 144 schedule_tail(current->thread.prev_sched); 145 146 /* 147 * XXX: if interrupt_end() calls schedule, this call to 148 * arch_switch_to isn't needed. We could want to apply this to 149 * improve performance. -bb 150 */ 151 arch_switch_to(current); 152 153 current->thread.prev_sched = NULL; 154 155 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); 156 } 157 158 int copy_thread(struct task_struct * p, const struct kernel_clone_args *args) 159 { 160 unsigned long clone_flags = args->flags; 161 unsigned long sp = args->stack; 162 unsigned long tls = args->tls; 163 void (*handler)(void); 164 int ret = 0; 165 166 p->thread = (struct thread_struct) INIT_THREAD; 167 168 if (!args->fn) { 169 memcpy(&p->thread.regs.regs, current_pt_regs(), 170 sizeof(p->thread.regs.regs)); 171 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0); 172 if (sp != 0) 173 REGS_SP(p->thread.regs.regs.gp) = sp; 174 175 handler = fork_handler; 176 177 arch_copy_thread(¤t->thread.arch, &p->thread.arch); 178 } else { 179 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp); 180 p->thread.request.u.thread.proc = args->fn; 181 p->thread.request.u.thread.arg = args->fn_arg; 182 handler = new_thread_handler; 183 } 184 185 new_thread(task_stack_page(p), &p->thread.switch_buf, handler); 186 187 if (!args->fn) { 188 clear_flushed_tls(p); 189 190 /* 191 * Set a new TLS for the child thread? 192 */ 193 if (clone_flags & CLONE_SETTLS) 194 ret = arch_set_tls(p, tls); 195 } 196 197 return ret; 198 } 199 200 void initial_thread_cb(void (*proc)(void *), void *arg) 201 { 202 int save_kmalloc_ok = kmalloc_ok; 203 204 kmalloc_ok = 0; 205 initial_thread_cb_skas(proc, arg); 206 kmalloc_ok = save_kmalloc_ok; 207 } 208 209 void um_idle_sleep(void) 210 { 211 if (time_travel_mode != TT_MODE_OFF) 212 time_travel_sleep(); 213 else 214 os_idle_sleep(); 215 } 216 217 void arch_cpu_idle(void) 218 { 219 cpu_tasks[current_thread_info()->cpu].pid = os_getpid(); 220 um_idle_sleep(); 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 static atomic_t using_sysemu = ATOMIC_INIT(0); 269 int sysemu_supported; 270 271 void set_using_sysemu(int value) 272 { 273 if (value > sysemu_supported) 274 return; 275 atomic_set(&using_sysemu, value); 276 } 277 278 int get_using_sysemu(void) 279 { 280 return atomic_read(&using_sysemu); 281 } 282 283 static int sysemu_proc_show(struct seq_file *m, void *v) 284 { 285 seq_printf(m, "%d\n", get_using_sysemu()); 286 return 0; 287 } 288 289 static int sysemu_proc_open(struct inode *inode, struct file *file) 290 { 291 return single_open(file, sysemu_proc_show, NULL); 292 } 293 294 static ssize_t sysemu_proc_write(struct file *file, const char __user *buf, 295 size_t count, loff_t *pos) 296 { 297 char tmp[2]; 298 299 if (copy_from_user(tmp, buf, 1)) 300 return -EFAULT; 301 302 if (tmp[0] >= '0' && tmp[0] <= '2') 303 set_using_sysemu(tmp[0] - '0'); 304 /* We use the first char, but pretend to write everything */ 305 return count; 306 } 307 308 static const struct proc_ops sysemu_proc_ops = { 309 .proc_open = sysemu_proc_open, 310 .proc_read = seq_read, 311 .proc_lseek = seq_lseek, 312 .proc_release = single_release, 313 .proc_write = sysemu_proc_write, 314 }; 315 316 int __init make_proc_sysemu(void) 317 { 318 struct proc_dir_entry *ent; 319 if (!sysemu_supported) 320 return 0; 321 322 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops); 323 324 if (ent == NULL) 325 { 326 printk(KERN_WARNING "Failed to register /proc/sysemu\n"); 327 return 0; 328 } 329 330 return 0; 331 } 332 333 late_initcall(make_proc_sysemu); 334 335 int singlestepping(void * t) 336 { 337 struct task_struct *task = t ? t : current; 338 339 if (!test_thread_flag(TIF_SINGLESTEP)) 340 return 0; 341 342 if (task->thread.singlestep_syscall) 343 return 1; 344 345 return 2; 346 } 347 348 /* 349 * Only x86 and x86_64 have an arch_align_stack(). 350 * All other arches have "#define arch_align_stack(x) (x)" 351 * in their asm/exec.h 352 * As this is included in UML from asm-um/system-generic.h, 353 * we can use it to behave as the subarch does. 354 */ 355 #ifndef arch_align_stack 356 unsigned long arch_align_stack(unsigned long sp) 357 { 358 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 359 sp -= get_random_u32_below(8192); 360 return sp & ~0xf; 361 } 362 #endif 363 364 unsigned long __get_wchan(struct task_struct *p) 365 { 366 unsigned long stack_page, sp, ip; 367 bool seen_sched = 0; 368 369 stack_page = (unsigned long) task_stack_page(p); 370 /* Bail if the process has no kernel stack for some reason */ 371 if (stack_page == 0) 372 return 0; 373 374 sp = p->thread.switch_buf->JB_SP; 375 /* 376 * Bail if the stack pointer is below the bottom of the kernel 377 * stack for some reason 378 */ 379 if (sp < stack_page) 380 return 0; 381 382 while (sp < stack_page + THREAD_SIZE) { 383 ip = *((unsigned long *) sp); 384 if (in_sched_functions(ip)) 385 /* Ignore everything until we're above the scheduler */ 386 seen_sched = 1; 387 else if (kernel_text_address(ip) && seen_sched) 388 return ip; 389 390 sp += sizeof(unsigned long); 391 } 392 393 return 0; 394 } 395 396 int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu) 397 { 398 int cpu = current_thread_info()->cpu; 399 400 return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu); 401 } 402 403