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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/cpu.h>
19#include <linux/slab.h>
20#include <linux/sched.h>
21#include <linux/sched/debug.h>
22#include <linux/sched/task.h>
23#include <linux/sched/task_stack.h>
24#include <linux/seq_file.h>
25#include <linux/tick.h>
26#include <linux/threads.h>
27#include <linux/resume_user_mode.h>
28#include <asm/current.h>
29#include <asm/mmu_context.h>
30#include <asm/switch_to.h>
31#include <asm/exec.h>
32#include <linux/uaccess.h>
33#include <as-layout.h>
34#include <kern_util.h>
35#include <os.h>
36#include <skas.h>
37#include <registers.h>
38#include <linux/time-internal.h>
39#include <linux/elfcore.h>
40
41/*
42 * This is a per-cpu array. A processor only modifies its entry and it only
43 * cares about its entry, so it's OK if another processor is modifying its
44 * entry.
45 */
46struct task_struct *cpu_tasks[NR_CPUS];
47EXPORT_SYMBOL(cpu_tasks);
48
49void free_stack(unsigned long stack, int order)
50{
51 free_pages(stack, order);
52}
53
54unsigned long alloc_stack(int order, int atomic)
55{
56 unsigned long page;
57 gfp_t flags = GFP_KERNEL;
58
59 if (atomic)
60 flags = GFP_ATOMIC;
61 page = __get_free_pages(flags, order);
62
63 return page;
64}
65
66static inline void set_current(struct task_struct *task)
67{
68 cpu_tasks[task_thread_info(task)->cpu] = task;
69}
70
71struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to)
72{
73 to->thread.prev_sched = from;
74 set_current(to);
75
76 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
77 arch_switch_to(current);
78
79 return current->thread.prev_sched;
80}
81
82void interrupt_end(void)
83{
84 struct pt_regs *regs = ¤t->thread.regs;
85
86 if (need_resched())
87 schedule();
88 if (test_thread_flag(TIF_SIGPENDING) ||
89 test_thread_flag(TIF_NOTIFY_SIGNAL))
90 do_signal(regs);
91 if (test_thread_flag(TIF_NOTIFY_RESUME))
92 resume_user_mode_work(regs);
93}
94
95int get_current_pid(void)
96{
97 return task_pid_nr(current);
98}
99
100/*
101 * This is called magically, by its address being stuffed in a jmp_buf
102 * and being longjmp-d to.
103 */
104void new_thread_handler(void)
105{
106 int (*fn)(void *);
107 void *arg;
108
109 if (current->thread.prev_sched != NULL)
110 schedule_tail(current->thread.prev_sched);
111 current->thread.prev_sched = NULL;
112
113 fn = current->thread.request.thread.proc;
114 arg = current->thread.request.thread.arg;
115
116 /*
117 * callback returns only if the kernel thread execs a process
118 */
119 fn(arg);
120 userspace(¤t->thread.regs.regs);
121}
122
123/* Called magically, see new_thread_handler above */
124static void fork_handler(void)
125{
126 schedule_tail(current->thread.prev_sched);
127
128 /*
129 * XXX: if interrupt_end() calls schedule, this call to
130 * arch_switch_to isn't needed. We could want to apply this to
131 * improve performance. -bb
132 */
133 arch_switch_to(current);
134
135 current->thread.prev_sched = NULL;
136
137 userspace(¤t->thread.regs.regs);
138}
139
140int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
141{
142 unsigned long clone_flags = args->flags;
143 unsigned long sp = args->stack;
144 unsigned long tls = args->tls;
145 void (*handler)(void);
146 int ret = 0;
147
148 p->thread = (struct thread_struct) INIT_THREAD;
149
150 if (!args->fn) {
151 memcpy(&p->thread.regs.regs, current_pt_regs(),
152 sizeof(p->thread.regs.regs));
153 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
154 if (sp != 0)
155 REGS_SP(p->thread.regs.regs.gp) = sp;
156
157 handler = fork_handler;
158
159 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
160 } else {
161 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
162 p->thread.request.thread.proc = args->fn;
163 p->thread.request.thread.arg = args->fn_arg;
164 handler = new_thread_handler;
165 }
166
167 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
168
169 if (!args->fn) {
170 clear_flushed_tls(p);
171
172 /*
173 * Set a new TLS for the child thread?
174 */
175 if (clone_flags & CLONE_SETTLS)
176 ret = arch_set_tls(p, tls);
177 }
178
179 return ret;
180}
181
182void initial_thread_cb(void (*proc)(void *), void *arg)
183{
184 int save_kmalloc_ok = kmalloc_ok;
185
186 kmalloc_ok = 0;
187 initial_thread_cb_skas(proc, arg);
188 kmalloc_ok = save_kmalloc_ok;
189}
190
191int arch_dup_task_struct(struct task_struct *dst,
192 struct task_struct *src)
193{
194 /* init_task is not dynamically sized (missing FPU state) */
195 if (unlikely(src == &init_task)) {
196 memcpy(dst, src, sizeof(init_task));
197 memset((void *)dst + sizeof(init_task), 0,
198 arch_task_struct_size - sizeof(init_task));
199 } else {
200 memcpy(dst, src, arch_task_struct_size);
201 }
202
203 return 0;
204}
205
206void um_idle_sleep(void)
207{
208 if (time_travel_mode != TT_MODE_OFF)
209 time_travel_sleep();
210 else
211 os_idle_sleep();
212}
213
214void arch_cpu_idle(void)
215{
216 um_idle_sleep();
217}
218
219int __uml_cant_sleep(void) {
220 return in_atomic() || irqs_disabled() || in_interrupt();
221 /* Is in_interrupt() really needed? */
222}
223
224int user_context(unsigned long sp)
225{
226 unsigned long stack;
227
228 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
229 return stack != (unsigned long) current_thread_info();
230}
231
232extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
233
234void do_uml_exitcalls(void)
235{
236 exitcall_t *call;
237
238 call = &__uml_exitcall_end;
239 while (--call >= &__uml_exitcall_begin)
240 (*call)();
241}
242
243char *uml_strdup(const char *string)
244{
245 return kstrdup(string, GFP_KERNEL);
246}
247EXPORT_SYMBOL(uml_strdup);
248
249int copy_from_user_proc(void *to, void __user *from, int size)
250{
251 return copy_from_user(to, from, size);
252}
253
254int singlestepping(void)
255{
256 return test_thread_flag(TIF_SINGLESTEP);
257}
258
259/*
260 * Only x86 and x86_64 have an arch_align_stack().
261 * All other arches have "#define arch_align_stack(x) (x)"
262 * in their asm/exec.h
263 * As this is included in UML from asm-um/system-generic.h,
264 * we can use it to behave as the subarch does.
265 */
266#ifndef arch_align_stack
267unsigned long arch_align_stack(unsigned long sp)
268{
269 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
270 sp -= get_random_u32_below(8192);
271 return sp & ~0xf;
272}
273#endif
274
275unsigned long __get_wchan(struct task_struct *p)
276{
277 unsigned long stack_page, sp, ip;
278 bool seen_sched = 0;
279
280 stack_page = (unsigned long) task_stack_page(p);
281 /* Bail if the process has no kernel stack for some reason */
282 if (stack_page == 0)
283 return 0;
284
285 sp = p->thread.switch_buf->JB_SP;
286 /*
287 * Bail if the stack pointer is below the bottom of the kernel
288 * stack for some reason
289 */
290 if (sp < stack_page)
291 return 0;
292
293 while (sp < stack_page + THREAD_SIZE) {
294 ip = *((unsigned long *) sp);
295 if (in_sched_functions(ip))
296 /* Ignore everything until we're above the scheduler */
297 seen_sched = 1;
298 else if (kernel_text_address(ip) && seen_sched)
299 return ip;
300
301 sp += sizeof(unsigned long);
302 }
303
304 return 0;
305}
1/*
2 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
4 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 * Copyright 2003 PathScale, Inc.
6 * Licensed under the GPL
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/seq_file.h>
21#include <linux/tick.h>
22#include <linux/threads.h>
23#include <linux/tracehook.h>
24#include <asm/current.h>
25#include <asm/pgtable.h>
26#include <asm/mmu_context.h>
27#include <linux/uaccess.h>
28#include <as-layout.h>
29#include <kern_util.h>
30#include <os.h>
31#include <skas.h>
32#include <timer-internal.h>
33
34/*
35 * This is a per-cpu array. A processor only modifies its entry and it only
36 * cares about its entry, so it's OK if another processor is modifying its
37 * entry.
38 */
39struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
40
41static inline int external_pid(void)
42{
43 /* FIXME: Need to look up userspace_pid by cpu */
44 return userspace_pid[0];
45}
46
47int pid_to_processor_id(int pid)
48{
49 int i;
50
51 for (i = 0; i < ncpus; i++) {
52 if (cpu_tasks[i].pid == pid)
53 return i;
54 }
55 return -1;
56}
57
58void free_stack(unsigned long stack, int order)
59{
60 free_pages(stack, order);
61}
62
63unsigned long alloc_stack(int order, int atomic)
64{
65 unsigned long page;
66 gfp_t flags = GFP_KERNEL;
67
68 if (atomic)
69 flags = GFP_ATOMIC;
70 page = __get_free_pages(flags, order);
71
72 return page;
73}
74
75static inline void set_current(struct task_struct *task)
76{
77 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
78 { external_pid(), task });
79}
80
81extern void arch_switch_to(struct task_struct *to);
82
83void *__switch_to(struct task_struct *from, struct task_struct *to)
84{
85 to->thread.prev_sched = from;
86 set_current(to);
87
88 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
89 arch_switch_to(current);
90
91 return current->thread.prev_sched;
92}
93
94void interrupt_end(void)
95{
96 struct pt_regs *regs = ¤t->thread.regs;
97
98 if (need_resched())
99 schedule();
100 if (test_thread_flag(TIF_SIGPENDING))
101 do_signal(regs);
102 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
103 tracehook_notify_resume(regs);
104}
105
106int get_current_pid(void)
107{
108 return task_pid_nr(current);
109}
110
111/*
112 * This is called magically, by its address being stuffed in a jmp_buf
113 * and being longjmp-d to.
114 */
115void new_thread_handler(void)
116{
117 int (*fn)(void *), n;
118 void *arg;
119
120 if (current->thread.prev_sched != NULL)
121 schedule_tail(current->thread.prev_sched);
122 current->thread.prev_sched = NULL;
123
124 fn = current->thread.request.u.thread.proc;
125 arg = current->thread.request.u.thread.arg;
126
127 /*
128 * callback returns only if the kernel thread execs a process
129 */
130 n = fn(arg);
131 userspace(¤t->thread.regs.regs);
132}
133
134/* Called magically, see new_thread_handler above */
135void fork_handler(void)
136{
137 force_flush_all();
138
139 schedule_tail(current->thread.prev_sched);
140
141 /*
142 * XXX: if interrupt_end() calls schedule, this call to
143 * arch_switch_to isn't needed. We could want to apply this to
144 * improve performance. -bb
145 */
146 arch_switch_to(current);
147
148 current->thread.prev_sched = NULL;
149
150 userspace(¤t->thread.regs.regs);
151}
152
153int copy_thread(unsigned long clone_flags, unsigned long sp,
154 unsigned long arg, struct task_struct * p)
155{
156 void (*handler)(void);
157 int kthread = current->flags & PF_KTHREAD;
158 int ret = 0;
159
160 p->thread = (struct thread_struct) INIT_THREAD;
161
162 if (!kthread) {
163 memcpy(&p->thread.regs.regs, current_pt_regs(),
164 sizeof(p->thread.regs.regs));
165 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
166 if (sp != 0)
167 REGS_SP(p->thread.regs.regs.gp) = sp;
168
169 handler = fork_handler;
170
171 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
172 } else {
173 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
174 p->thread.request.u.thread.proc = (int (*)(void *))sp;
175 p->thread.request.u.thread.arg = (void *)arg;
176 handler = new_thread_handler;
177 }
178
179 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
180
181 if (!kthread) {
182 clear_flushed_tls(p);
183
184 /*
185 * Set a new TLS for the child thread?
186 */
187 if (clone_flags & CLONE_SETTLS)
188 ret = arch_copy_tls(p);
189 }
190
191 return ret;
192}
193
194void initial_thread_cb(void (*proc)(void *), void *arg)
195{
196 int save_kmalloc_ok = kmalloc_ok;
197
198 kmalloc_ok = 0;
199 initial_thread_cb_skas(proc, arg);
200 kmalloc_ok = save_kmalloc_ok;
201}
202
203void arch_cpu_idle(void)
204{
205 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
206 os_idle_sleep(UM_NSEC_PER_SEC);
207 local_irq_enable();
208}
209
210int __cant_sleep(void) {
211 return in_atomic() || irqs_disabled() || in_interrupt();
212 /* Is in_interrupt() really needed? */
213}
214
215int user_context(unsigned long sp)
216{
217 unsigned long stack;
218
219 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
220 return stack != (unsigned long) current_thread_info();
221}
222
223extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
224
225void do_uml_exitcalls(void)
226{
227 exitcall_t *call;
228
229 call = &__uml_exitcall_end;
230 while (--call >= &__uml_exitcall_begin)
231 (*call)();
232}
233
234char *uml_strdup(const char *string)
235{
236 return kstrdup(string, GFP_KERNEL);
237}
238EXPORT_SYMBOL(uml_strdup);
239
240int copy_to_user_proc(void __user *to, void *from, int size)
241{
242 return copy_to_user(to, from, size);
243}
244
245int copy_from_user_proc(void *to, void __user *from, int size)
246{
247 return copy_from_user(to, from, size);
248}
249
250int clear_user_proc(void __user *buf, int size)
251{
252 return clear_user(buf, size);
253}
254
255int strlen_user_proc(char __user *str)
256{
257 return strlen_user(str);
258}
259
260int cpu(void)
261{
262 return current_thread_info()->cpu;
263}
264
265static atomic_t using_sysemu = ATOMIC_INIT(0);
266int sysemu_supported;
267
268void set_using_sysemu(int value)
269{
270 if (value > sysemu_supported)
271 return;
272 atomic_set(&using_sysemu, value);
273}
274
275int get_using_sysemu(void)
276{
277 return atomic_read(&using_sysemu);
278}
279
280static int sysemu_proc_show(struct seq_file *m, void *v)
281{
282 seq_printf(m, "%d\n", get_using_sysemu());
283 return 0;
284}
285
286static int sysemu_proc_open(struct inode *inode, struct file *file)
287{
288 return single_open(file, sysemu_proc_show, NULL);
289}
290
291static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
292 size_t count, loff_t *pos)
293{
294 char tmp[2];
295
296 if (copy_from_user(tmp, buf, 1))
297 return -EFAULT;
298
299 if (tmp[0] >= '0' && tmp[0] <= '2')
300 set_using_sysemu(tmp[0] - '0');
301 /* We use the first char, but pretend to write everything */
302 return count;
303}
304
305static const struct file_operations sysemu_proc_fops = {
306 .owner = THIS_MODULE,
307 .open = sysemu_proc_open,
308 .read = seq_read,
309 .llseek = seq_lseek,
310 .release = single_release,
311 .write = sysemu_proc_write,
312};
313
314int __init make_proc_sysemu(void)
315{
316 struct proc_dir_entry *ent;
317 if (!sysemu_supported)
318 return 0;
319
320 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_fops);
321
322 if (ent == NULL)
323 {
324 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
325 return 0;
326 }
327
328 return 0;
329}
330
331late_initcall(make_proc_sysemu);
332
333int singlestepping(void * t)
334{
335 struct task_struct *task = t ? t : current;
336
337 if (!(task->ptrace & PT_DTRACE))
338 return 0;
339
340 if (task->thread.singlestep_syscall)
341 return 1;
342
343 return 2;
344}
345
346/*
347 * Only x86 and x86_64 have an arch_align_stack().
348 * All other arches have "#define arch_align_stack(x) (x)"
349 * in their asm/exec.h
350 * As this is included in UML from asm-um/system-generic.h,
351 * we can use it to behave as the subarch does.
352 */
353#ifndef arch_align_stack
354unsigned long arch_align_stack(unsigned long sp)
355{
356 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
357 sp -= get_random_int() % 8192;
358 return sp & ~0xf;
359}
360#endif
361
362unsigned long get_wchan(struct task_struct *p)
363{
364 unsigned long stack_page, sp, ip;
365 bool seen_sched = 0;
366
367 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
368 return 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_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