1 // SPDX-License-Identifier: GPL-2.0
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.
9 #include <linux/stddef.h>
10 #include <linux/err.h>
11 #include <linux/hardirq.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>
34 #include <linux/time-internal.h>
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
41 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
43 static inline int external_pid(void)
45 /* FIXME: Need to look up userspace_pid by cpu */
46 return userspace_pid[0];
49 int pid_to_processor_id(int pid)
53 for (i = 0; i < ncpus; i++) {
54 if (cpu_tasks[i].pid == pid)
60 void free_stack(unsigned long stack, int order)
62 free_pages(stack, order);
65 unsigned long alloc_stack(int order, int atomic)
68 gfp_t flags = GFP_KERNEL;
72 page = __get_free_pages(flags, order);
77 static inline void set_current(struct task_struct *task)
79 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
80 { external_pid(), task });
83 extern void arch_switch_to(struct task_struct *to);
85 void *__switch_to(struct task_struct *from, struct task_struct *to)
87 to->thread.prev_sched = from;
90 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
91 arch_switch_to(current);
93 return current->thread.prev_sched;
96 void interrupt_end(void)
98 struct pt_regs *regs = ¤t->thread.regs;
102 if (test_thread_flag(TIF_SIGPENDING))
104 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
105 tracehook_notify_resume(regs);
108 int get_current_pid(void)
110 return task_pid_nr(current);
114 * This is called magically, by its address being stuffed in a jmp_buf
115 * and being longjmp-d to.
117 void new_thread_handler(void)
119 int (*fn)(void *), n;
122 if (current->thread.prev_sched != NULL)
123 schedule_tail(current->thread.prev_sched);
124 current->thread.prev_sched = NULL;
126 fn = current->thread.request.u.thread.proc;
127 arg = current->thread.request.u.thread.arg;
130 * callback returns only if the kernel thread execs a process
133 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs);
136 /* Called magically, see new_thread_handler above */
137 void fork_handler(void)
141 schedule_tail(current->thread.prev_sched);
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
148 arch_switch_to(current);
150 current->thread.prev_sched = NULL;
152 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs);
155 int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
156 unsigned long arg, struct task_struct * p, unsigned long tls)
158 void (*handler)(void);
159 int kthread = current->flags & PF_KTHREAD;
162 p->thread = (struct thread_struct) INIT_THREAD;
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);
169 REGS_SP(p->thread.regs.regs.gp) = sp;
171 handler = fork_handler;
173 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
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;
181 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
184 clear_flushed_tls(p);
187 * Set a new TLS for the child thread?
189 if (clone_flags & CLONE_SETTLS)
190 ret = arch_set_tls(p, tls);
196 void initial_thread_cb(void (*proc)(void *), void *arg)
198 int save_kmalloc_ok = kmalloc_ok;
201 initial_thread_cb_skas(proc, arg);
202 kmalloc_ok = save_kmalloc_ok;
205 static void um_idle_sleep(void)
207 unsigned long long duration = UM_NSEC_PER_SEC;
209 if (time_travel_mode != TT_MODE_OFF) {
210 time_travel_sleep(duration);
212 os_idle_sleep(duration);
216 void arch_cpu_idle(void)
218 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
223 int __cant_sleep(void) {
224 return in_atomic() || irqs_disabled() || in_interrupt();
225 /* Is in_interrupt() really needed? */
228 int user_context(unsigned long sp)
232 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
233 return stack != (unsigned long) current_thread_info();
236 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
238 void do_uml_exitcalls(void)
242 call = &__uml_exitcall_end;
243 while (--call >= &__uml_exitcall_begin)
247 char *uml_strdup(const char *string)
249 return kstrdup(string, GFP_KERNEL);
251 EXPORT_SYMBOL(uml_strdup);
253 int copy_to_user_proc(void __user *to, void *from, int size)
255 return copy_to_user(to, from, size);
258 int copy_from_user_proc(void *to, void __user *from, int size)
260 return copy_from_user(to, from, size);
263 int clear_user_proc(void __user *buf, int size)
265 return clear_user(buf, size);
270 return current_thread_info()->cpu;
273 static atomic_t using_sysemu = ATOMIC_INIT(0);
274 int sysemu_supported;
276 void set_using_sysemu(int value)
278 if (value > sysemu_supported)
280 atomic_set(&using_sysemu, value);
283 int get_using_sysemu(void)
285 return atomic_read(&using_sysemu);
288 static int sysemu_proc_show(struct seq_file *m, void *v)
290 seq_printf(m, "%d\n", get_using_sysemu());
294 static int sysemu_proc_open(struct inode *inode, struct file *file)
296 return single_open(file, sysemu_proc_show, NULL);
299 static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
300 size_t count, loff_t *pos)
304 if (copy_from_user(tmp, buf, 1))
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 */
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,
321 int __init make_proc_sysemu(void)
323 struct proc_dir_entry *ent;
324 if (!sysemu_supported)
327 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops);
331 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
338 late_initcall(make_proc_sysemu);
340 int singlestepping(void * t)
342 struct task_struct *task = t ? t : current;
344 if (!(task->ptrace & PT_DTRACE))
347 if (task->thread.singlestep_syscall)
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.
360 #ifndef arch_align_stack
361 unsigned long arch_align_stack(unsigned long sp)
363 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
364 sp -= get_random_int() % 8192;
369 unsigned long get_wchan(struct task_struct *p)
371 unsigned long stack_page, sp, ip;
374 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
377 stack_page = (unsigned long) task_stack_page(p);
378 /* Bail if the process has no kernel stack for some reason */
382 sp = p->thread.switch_buf->JB_SP;
384 * Bail if the stack pointer is below the bottom of the kernel
385 * stack for some reason
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 */
395 else if (kernel_text_address(ip) && seen_sched)
398 sp += sizeof(unsigned long);
404 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
406 int cpu = current_thread_info()->cpu;
408 return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu);