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1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Copyright 2003 PathScale, Inc.
4 * Licensed under the GPL
5 */
6
7#include <linux/stddef.h>
8#include <linux/err.h>
9#include <linux/hardirq.h>
10#include <linux/mm.h>
11#include <linux/module.h>
12#include <linux/personality.h>
13#include <linux/proc_fs.h>
14#include <linux/ptrace.h>
15#include <linux/random.h>
16#include <linux/slab.h>
17#include <linux/sched.h>
18#include <linux/seq_file.h>
19#include <linux/tick.h>
20#include <linux/threads.h>
21#include <linux/tracehook.h>
22#include <asm/current.h>
23#include <asm/pgtable.h>
24#include <asm/mmu_context.h>
25#include <asm/uaccess.h>
26#include "as-layout.h"
27#include "kern_util.h"
28#include "os.h"
29#include "skas.h"
30
31/*
32 * This is a per-cpu array. A processor only modifies its entry and it only
33 * cares about its entry, so it's OK if another processor is modifying its
34 * entry.
35 */
36struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
37
38static inline int external_pid(void)
39{
40 /* FIXME: Need to look up userspace_pid by cpu */
41 return userspace_pid[0];
42}
43
44int pid_to_processor_id(int pid)
45{
46 int i;
47
48 for (i = 0; i < ncpus; i++) {
49 if (cpu_tasks[i].pid == pid)
50 return i;
51 }
52 return -1;
53}
54
55void free_stack(unsigned long stack, int order)
56{
57 free_pages(stack, order);
58}
59
60unsigned long alloc_stack(int order, int atomic)
61{
62 unsigned long page;
63 gfp_t flags = GFP_KERNEL;
64
65 if (atomic)
66 flags = GFP_ATOMIC;
67 page = __get_free_pages(flags, order);
68
69 return page;
70}
71
72int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
73{
74 int pid;
75
76 current->thread.request.u.thread.proc = fn;
77 current->thread.request.u.thread.arg = arg;
78 pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
79 ¤t->thread.regs, 0, NULL, NULL);
80 return pid;
81}
82EXPORT_SYMBOL(kernel_thread);
83
84static inline void set_current(struct task_struct *task)
85{
86 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
87 { external_pid(), task });
88}
89
90extern void arch_switch_to(struct task_struct *to);
91
92void *__switch_to(struct task_struct *from, struct task_struct *to)
93{
94 to->thread.prev_sched = from;
95 set_current(to);
96
97 do {
98 current->thread.saved_task = NULL;
99
100 switch_threads(&from->thread.switch_buf,
101 &to->thread.switch_buf);
102
103 arch_switch_to(current);
104
105 if (current->thread.saved_task)
106 show_regs(&(current->thread.regs));
107 to = current->thread.saved_task;
108 from = current;
109 } while (current->thread.saved_task);
110
111 return current->thread.prev_sched;
112}
113
114void interrupt_end(void)
115{
116 if (need_resched())
117 schedule();
118 if (test_thread_flag(TIF_SIGPENDING))
119 do_signal();
120 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
121 tracehook_notify_resume(¤t->thread.regs);
122}
123
124void exit_thread(void)
125{
126}
127
128int get_current_pid(void)
129{
130 return task_pid_nr(current);
131}
132
133/*
134 * This is called magically, by its address being stuffed in a jmp_buf
135 * and being longjmp-d to.
136 */
137void new_thread_handler(void)
138{
139 int (*fn)(void *), n;
140 void *arg;
141
142 if (current->thread.prev_sched != NULL)
143 schedule_tail(current->thread.prev_sched);
144 current->thread.prev_sched = NULL;
145
146 fn = current->thread.request.u.thread.proc;
147 arg = current->thread.request.u.thread.arg;
148
149 /*
150 * The return value is 1 if the kernel thread execs a process,
151 * 0 if it just exits
152 */
153 n = run_kernel_thread(fn, arg, ¤t->thread.exec_buf);
154 if (n == 1) {
155 /* Handle any immediate reschedules or signals */
156 interrupt_end();
157 userspace(¤t->thread.regs.regs);
158 }
159 else do_exit(0);
160}
161
162/* Called magically, see new_thread_handler above */
163void fork_handler(void)
164{
165 force_flush_all();
166
167 schedule_tail(current->thread.prev_sched);
168
169 /*
170 * XXX: if interrupt_end() calls schedule, this call to
171 * arch_switch_to isn't needed. We could want to apply this to
172 * improve performance. -bb
173 */
174 arch_switch_to(current);
175
176 current->thread.prev_sched = NULL;
177
178 /* Handle any immediate reschedules or signals */
179 interrupt_end();
180
181 userspace(¤t->thread.regs.regs);
182}
183
184int copy_thread(unsigned long clone_flags, unsigned long sp,
185 unsigned long stack_top, struct task_struct * p,
186 struct pt_regs *regs)
187{
188 void (*handler)(void);
189 int ret = 0;
190
191 p->thread = (struct thread_struct) INIT_THREAD;
192
193 if (current->thread.forking) {
194 memcpy(&p->thread.regs.regs, ®s->regs,
195 sizeof(p->thread.regs.regs));
196 UPT_SET_SYSCALL_RETURN(&p->thread.regs.regs, 0);
197 if (sp != 0)
198 REGS_SP(p->thread.regs.regs.gp) = sp;
199
200 handler = fork_handler;
201
202 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
203 }
204 else {
205 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
206 p->thread.request.u.thread = current->thread.request.u.thread;
207 handler = new_thread_handler;
208 }
209
210 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
211
212 if (current->thread.forking) {
213 clear_flushed_tls(p);
214
215 /*
216 * Set a new TLS for the child thread?
217 */
218 if (clone_flags & CLONE_SETTLS)
219 ret = arch_copy_tls(p);
220 }
221
222 return ret;
223}
224
225void initial_thread_cb(void (*proc)(void *), void *arg)
226{
227 int save_kmalloc_ok = kmalloc_ok;
228
229 kmalloc_ok = 0;
230 initial_thread_cb_skas(proc, arg);
231 kmalloc_ok = save_kmalloc_ok;
232}
233
234void default_idle(void)
235{
236 unsigned long long nsecs;
237
238 while (1) {
239 /* endless idle loop with no priority at all */
240
241 /*
242 * although we are an idle CPU, we do not want to
243 * get into the scheduler unnecessarily.
244 */
245 if (need_resched())
246 schedule();
247
248 tick_nohz_idle_enter();
249 rcu_idle_enter();
250 nsecs = disable_timer();
251 idle_sleep(nsecs);
252 rcu_idle_exit();
253 tick_nohz_idle_exit();
254 }
255}
256
257void cpu_idle(void)
258{
259 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
260 default_idle();
261}
262
263int __cant_sleep(void) {
264 return in_atomic() || irqs_disabled() || in_interrupt();
265 /* Is in_interrupt() really needed? */
266}
267
268int user_context(unsigned long sp)
269{
270 unsigned long stack;
271
272 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
273 return stack != (unsigned long) current_thread_info();
274}
275
276extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
277
278void do_uml_exitcalls(void)
279{
280 exitcall_t *call;
281
282 call = &__uml_exitcall_end;
283 while (--call >= &__uml_exitcall_begin)
284 (*call)();
285}
286
287char *uml_strdup(const char *string)
288{
289 return kstrdup(string, GFP_KERNEL);
290}
291EXPORT_SYMBOL(uml_strdup);
292
293int copy_to_user_proc(void __user *to, void *from, int size)
294{
295 return copy_to_user(to, from, size);
296}
297
298int copy_from_user_proc(void *to, void __user *from, int size)
299{
300 return copy_from_user(to, from, size);
301}
302
303int clear_user_proc(void __user *buf, int size)
304{
305 return clear_user(buf, size);
306}
307
308int strlen_user_proc(char __user *str)
309{
310 return strlen_user(str);
311}
312
313int smp_sigio_handler(void)
314{
315#ifdef CONFIG_SMP
316 int cpu = current_thread_info()->cpu;
317 IPI_handler(cpu);
318 if (cpu != 0)
319 return 1;
320#endif
321 return 0;
322}
323
324int cpu(void)
325{
326 return current_thread_info()->cpu;
327}
328
329static atomic_t using_sysemu = ATOMIC_INIT(0);
330int sysemu_supported;
331
332void set_using_sysemu(int value)
333{
334 if (value > sysemu_supported)
335 return;
336 atomic_set(&using_sysemu, value);
337}
338
339int get_using_sysemu(void)
340{
341 return atomic_read(&using_sysemu);
342}
343
344static int sysemu_proc_show(struct seq_file *m, void *v)
345{
346 seq_printf(m, "%d\n", get_using_sysemu());
347 return 0;
348}
349
350static int sysemu_proc_open(struct inode *inode, struct file *file)
351{
352 return single_open(file, sysemu_proc_show, NULL);
353}
354
355static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
356 size_t count, loff_t *pos)
357{
358 char tmp[2];
359
360 if (copy_from_user(tmp, buf, 1))
361 return -EFAULT;
362
363 if (tmp[0] >= '0' && tmp[0] <= '2')
364 set_using_sysemu(tmp[0] - '0');
365 /* We use the first char, but pretend to write everything */
366 return count;
367}
368
369static const struct file_operations sysemu_proc_fops = {
370 .owner = THIS_MODULE,
371 .open = sysemu_proc_open,
372 .read = seq_read,
373 .llseek = seq_lseek,
374 .release = single_release,
375 .write = sysemu_proc_write,
376};
377
378int __init make_proc_sysemu(void)
379{
380 struct proc_dir_entry *ent;
381 if (!sysemu_supported)
382 return 0;
383
384 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_fops);
385
386 if (ent == NULL)
387 {
388 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
389 return 0;
390 }
391
392 return 0;
393}
394
395late_initcall(make_proc_sysemu);
396
397int singlestepping(void * t)
398{
399 struct task_struct *task = t ? t : current;
400
401 if (!(task->ptrace & PT_DTRACE))
402 return 0;
403
404 if (task->thread.singlestep_syscall)
405 return 1;
406
407 return 2;
408}
409
410/*
411 * Only x86 and x86_64 have an arch_align_stack().
412 * All other arches have "#define arch_align_stack(x) (x)"
413 * in their asm/system.h
414 * As this is included in UML from asm-um/system-generic.h,
415 * we can use it to behave as the subarch does.
416 */
417#ifndef arch_align_stack
418unsigned long arch_align_stack(unsigned long sp)
419{
420 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
421 sp -= get_random_int() % 8192;
422 return sp & ~0xf;
423}
424#endif
425
426unsigned long get_wchan(struct task_struct *p)
427{
428 unsigned long stack_page, sp, ip;
429 bool seen_sched = 0;
430
431 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
432 return 0;
433
434 stack_page = (unsigned long) task_stack_page(p);
435 /* Bail if the process has no kernel stack for some reason */
436 if (stack_page == 0)
437 return 0;
438
439 sp = p->thread.switch_buf->JB_SP;
440 /*
441 * Bail if the stack pointer is below the bottom of the kernel
442 * stack for some reason
443 */
444 if (sp < stack_page)
445 return 0;
446
447 while (sp < stack_page + THREAD_SIZE) {
448 ip = *((unsigned long *) sp);
449 if (in_sched_functions(ip))
450 /* Ignore everything until we're above the scheduler */
451 seen_sched = 1;
452 else if (kernel_text_address(ip) && seen_sched)
453 return ip;
454
455 sp += sizeof(unsigned long);
456 }
457
458 return 0;
459}
460
461int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
462{
463 int cpu = current_thread_info()->cpu;
464
465 return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
466}
467
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 */
43struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
44
45static inline int external_pid(void)
46{
47 /* FIXME: Need to look up userspace_pid by cpu */
48 return userspace_pid[0];
49}
50
51int 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
62void free_stack(unsigned long stack, int order)
63{
64 free_pages(stack, order);
65}
66
67unsigned 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
79static 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
85extern void arch_switch_to(struct task_struct *to);
86
87void *__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
98void 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
111int 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 */
120void 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 */
140void 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
158int 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
200void 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
209void 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
217void arch_cpu_idle(void)
218{
219 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
220 um_idle_sleep();
221 raw_local_irq_enable();
222}
223
224int __cant_sleep(void) {
225 return in_atomic() || irqs_disabled() || in_interrupt();
226 /* Is in_interrupt() really needed? */
227}
228
229int user_context(unsigned long sp)
230{
231 unsigned long stack;
232
233 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
234 return stack != (unsigned long) current_thread_info();
235}
236
237extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
238
239void do_uml_exitcalls(void)
240{
241 exitcall_t *call;
242
243 call = &__uml_exitcall_end;
244 while (--call >= &__uml_exitcall_begin)
245 (*call)();
246}
247
248char *uml_strdup(const char *string)
249{
250 return kstrdup(string, GFP_KERNEL);
251}
252EXPORT_SYMBOL(uml_strdup);
253
254int copy_to_user_proc(void __user *to, void *from, int size)
255{
256 return copy_to_user(to, from, size);
257}
258
259int copy_from_user_proc(void *to, void __user *from, int size)
260{
261 return copy_from_user(to, from, size);
262}
263
264int clear_user_proc(void __user *buf, int size)
265{
266 return clear_user(buf, size);
267}
268
269static atomic_t using_sysemu = ATOMIC_INIT(0);
270int sysemu_supported;
271
272void set_using_sysemu(int value)
273{
274 if (value > sysemu_supported)
275 return;
276 atomic_set(&using_sysemu, value);
277}
278
279int get_using_sysemu(void)
280{
281 return atomic_read(&using_sysemu);
282}
283
284static int sysemu_proc_show(struct seq_file *m, void *v)
285{
286 seq_printf(m, "%d\n", get_using_sysemu());
287 return 0;
288}
289
290static int sysemu_proc_open(struct inode *inode, struct file *file)
291{
292 return single_open(file, sysemu_proc_show, NULL);
293}
294
295static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
296 size_t count, loff_t *pos)
297{
298 char tmp[2];
299
300 if (copy_from_user(tmp, buf, 1))
301 return -EFAULT;
302
303 if (tmp[0] >= '0' && tmp[0] <= '2')
304 set_using_sysemu(tmp[0] - '0');
305 /* We use the first char, but pretend to write everything */
306 return count;
307}
308
309static const struct proc_ops sysemu_proc_ops = {
310 .proc_open = sysemu_proc_open,
311 .proc_read = seq_read,
312 .proc_lseek = seq_lseek,
313 .proc_release = single_release,
314 .proc_write = sysemu_proc_write,
315};
316
317int __init make_proc_sysemu(void)
318{
319 struct proc_dir_entry *ent;
320 if (!sysemu_supported)
321 return 0;
322
323 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops);
324
325 if (ent == NULL)
326 {
327 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
328 return 0;
329 }
330
331 return 0;
332}
333
334late_initcall(make_proc_sysemu);
335
336int singlestepping(void * t)
337{
338 struct task_struct *task = t ? t : current;
339
340 if (!test_thread_flag(TIF_SINGLESTEP))
341 return 0;
342
343 if (task->thread.singlestep_syscall)
344 return 1;
345
346 return 2;
347}
348
349/*
350 * Only x86 and x86_64 have an arch_align_stack().
351 * All other arches have "#define arch_align_stack(x) (x)"
352 * in their asm/exec.h
353 * As this is included in UML from asm-um/system-generic.h,
354 * we can use it to behave as the subarch does.
355 */
356#ifndef arch_align_stack
357unsigned long arch_align_stack(unsigned long sp)
358{
359 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
360 sp -= get_random_u32_below(8192);
361 return sp & ~0xf;
362}
363#endif
364
365unsigned long __get_wchan(struct task_struct *p)
366{
367 unsigned long stack_page, sp, ip;
368 bool seen_sched = 0;
369
370 stack_page = (unsigned long) task_stack_page(p);
371 /* Bail if the process has no kernel stack for some reason */
372 if (stack_page == 0)
373 return 0;
374
375 sp = p->thread.switch_buf->JB_SP;
376 /*
377 * Bail if the stack pointer is below the bottom of the kernel
378 * stack for some reason
379 */
380 if (sp < stack_page)
381 return 0;
382
383 while (sp < stack_page + THREAD_SIZE) {
384 ip = *((unsigned long *) sp);
385 if (in_sched_functions(ip))
386 /* Ignore everything until we're above the scheduler */
387 seen_sched = 1;
388 else if (kernel_text_address(ip) && seen_sched)
389 return ip;
390
391 sp += sizeof(unsigned long);
392 }
393
394 return 0;
395}
396
397int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
398{
399 int cpu = current_thread_info()->cpu;
400
401 return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu);
402}
403