Loading...
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) 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
72static inline void set_current(struct task_struct *task)
73{
74 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
75 { external_pid(), task });
76}
77
78extern void arch_switch_to(struct task_struct *to);
79
80void *__switch_to(struct task_struct *from, struct task_struct *to)
81{
82 to->thread.prev_sched = from;
83 set_current(to);
84
85 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
86 arch_switch_to(current);
87
88 return current->thread.prev_sched;
89}
90
91void interrupt_end(void)
92{
93 if (need_resched())
94 schedule();
95 if (test_thread_flag(TIF_SIGPENDING))
96 do_signal();
97 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
98 tracehook_notify_resume(¤t->thread.regs);
99}
100
101void exit_thread(void)
102{
103}
104
105int get_current_pid(void)
106{
107 return task_pid_nr(current);
108}
109
110/*
111 * This is called magically, by its address being stuffed in a jmp_buf
112 * and being longjmp-d to.
113 */
114void new_thread_handler(void)
115{
116 int (*fn)(void *), n;
117 void *arg;
118
119 if (current->thread.prev_sched != NULL)
120 schedule_tail(current->thread.prev_sched);
121 current->thread.prev_sched = NULL;
122
123 fn = current->thread.request.u.thread.proc;
124 arg = current->thread.request.u.thread.arg;
125
126 /*
127 * callback returns only if the kernel thread execs a process
128 */
129 n = fn(arg);
130 userspace(¤t->thread.regs.regs);
131}
132
133/* Called magically, see new_thread_handler above */
134void fork_handler(void)
135{
136 force_flush_all();
137
138 schedule_tail(current->thread.prev_sched);
139
140 /*
141 * XXX: if interrupt_end() calls schedule, this call to
142 * arch_switch_to isn't needed. We could want to apply this to
143 * improve performance. -bb
144 */
145 arch_switch_to(current);
146
147 current->thread.prev_sched = NULL;
148
149 userspace(¤t->thread.regs.regs);
150}
151
152int copy_thread(unsigned long clone_flags, unsigned long sp,
153 unsigned long arg, struct task_struct * p)
154{
155 void (*handler)(void);
156 int kthread = current->flags & PF_KTHREAD;
157 int ret = 0;
158
159 p->thread = (struct thread_struct) INIT_THREAD;
160
161 if (!kthread) {
162 memcpy(&p->thread.regs.regs, current_pt_regs(),
163 sizeof(p->thread.regs.regs));
164 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
165 if (sp != 0)
166 REGS_SP(p->thread.regs.regs.gp) = sp;
167
168 handler = fork_handler;
169
170 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
171 } else {
172 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
173 p->thread.request.u.thread.proc = (int (*)(void *))sp;
174 p->thread.request.u.thread.arg = (void *)arg;
175 handler = new_thread_handler;
176 }
177
178 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
179
180 if (!kthread) {
181 clear_flushed_tls(p);
182
183 /*
184 * Set a new TLS for the child thread?
185 */
186 if (clone_flags & CLONE_SETTLS)
187 ret = arch_copy_tls(p);
188 }
189
190 return ret;
191}
192
193void initial_thread_cb(void (*proc)(void *), void *arg)
194{
195 int save_kmalloc_ok = kmalloc_ok;
196
197 kmalloc_ok = 0;
198 initial_thread_cb_skas(proc, arg);
199 kmalloc_ok = save_kmalloc_ok;
200}
201
202void arch_cpu_idle(void)
203{
204 unsigned long long nsecs;
205
206 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
207 nsecs = disable_timer();
208 idle_sleep(nsecs);
209 local_irq_enable();
210}
211
212int __cant_sleep(void) {
213 return in_atomic() || irqs_disabled() || in_interrupt();
214 /* Is in_interrupt() really needed? */
215}
216
217int user_context(unsigned long sp)
218{
219 unsigned long stack;
220
221 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
222 return stack != (unsigned long) current_thread_info();
223}
224
225extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
226
227void do_uml_exitcalls(void)
228{
229 exitcall_t *call;
230
231 call = &__uml_exitcall_end;
232 while (--call >= &__uml_exitcall_begin)
233 (*call)();
234}
235
236char *uml_strdup(const char *string)
237{
238 return kstrdup(string, GFP_KERNEL);
239}
240EXPORT_SYMBOL(uml_strdup);
241
242int copy_to_user_proc(void __user *to, void *from, int size)
243{
244 return copy_to_user(to, from, size);
245}
246
247int copy_from_user_proc(void *to, void __user *from, int size)
248{
249 return copy_from_user(to, from, size);
250}
251
252int clear_user_proc(void __user *buf, int size)
253{
254 return clear_user(buf, size);
255}
256
257int strlen_user_proc(char __user *str)
258{
259 return strlen_user(str);
260}
261
262int smp_sigio_handler(void)
263{
264#ifdef CONFIG_SMP
265 int cpu = current_thread_info()->cpu;
266 IPI_handler(cpu);
267 if (cpu != 0)
268 return 1;
269#endif
270 return 0;
271}
272
273int cpu(void)
274{
275 return current_thread_info()->cpu;
276}
277
278static atomic_t using_sysemu = ATOMIC_INIT(0);
279int sysemu_supported;
280
281void set_using_sysemu(int value)
282{
283 if (value > sysemu_supported)
284 return;
285 atomic_set(&using_sysemu, value);
286}
287
288int get_using_sysemu(void)
289{
290 return atomic_read(&using_sysemu);
291}
292
293static int sysemu_proc_show(struct seq_file *m, void *v)
294{
295 seq_printf(m, "%d\n", get_using_sysemu());
296 return 0;
297}
298
299static int sysemu_proc_open(struct inode *inode, struct file *file)
300{
301 return single_open(file, sysemu_proc_show, NULL);
302}
303
304static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
305 size_t count, loff_t *pos)
306{
307 char tmp[2];
308
309 if (copy_from_user(tmp, buf, 1))
310 return -EFAULT;
311
312 if (tmp[0] >= '0' && tmp[0] <= '2')
313 set_using_sysemu(tmp[0] - '0');
314 /* We use the first char, but pretend to write everything */
315 return count;
316}
317
318static const struct file_operations sysemu_proc_fops = {
319 .owner = THIS_MODULE,
320 .open = sysemu_proc_open,
321 .read = seq_read,
322 .llseek = seq_lseek,
323 .release = single_release,
324 .write = sysemu_proc_write,
325};
326
327int __init make_proc_sysemu(void)
328{
329 struct proc_dir_entry *ent;
330 if (!sysemu_supported)
331 return 0;
332
333 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_fops);
334
335 if (ent == NULL)
336 {
337 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
338 return 0;
339 }
340
341 return 0;
342}
343
344late_initcall(make_proc_sysemu);
345
346int singlestepping(void * t)
347{
348 struct task_struct *task = t ? t : current;
349
350 if (!(task->ptrace & PT_DTRACE))
351 return 0;
352
353 if (task->thread.singlestep_syscall)
354 return 1;
355
356 return 2;
357}
358
359/*
360 * Only x86 and x86_64 have an arch_align_stack().
361 * All other arches have "#define arch_align_stack(x) (x)"
362 * in their asm/exec.h
363 * As this is included in UML from asm-um/system-generic.h,
364 * we can use it to behave as the subarch does.
365 */
366#ifndef arch_align_stack
367unsigned long arch_align_stack(unsigned long sp)
368{
369 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
370 sp -= get_random_int() % 8192;
371 return sp & ~0xf;
372}
373#endif
374
375unsigned long get_wchan(struct task_struct *p)
376{
377 unsigned long stack_page, sp, ip;
378 bool seen_sched = 0;
379
380 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
381 return 0;
382
383 stack_page = (unsigned long) task_stack_page(p);
384 /* Bail if the process has no kernel stack for some reason */
385 if (stack_page == 0)
386 return 0;
387
388 sp = p->thread.switch_buf->JB_SP;
389 /*
390 * Bail if the stack pointer is below the bottom of the kernel
391 * stack for some reason
392 */
393 if (sp < stack_page)
394 return 0;
395
396 while (sp < stack_page + THREAD_SIZE) {
397 ip = *((unsigned long *) sp);
398 if (in_sched_functions(ip))
399 /* Ignore everything until we're above the scheduler */
400 seen_sched = 1;
401 else if (kernel_text_address(ip) && seen_sched)
402 return ip;
403
404 sp += sizeof(unsigned long);
405 }
406
407 return 0;
408}
409
410int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
411{
412 int cpu = current_thread_info()->cpu;
413
414 return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
415}
416