10 #include <asm/ptrace-abi.h>
15 #include <stub-data.h>
18  * If needed we can detect when it's uninitialized.
22 static int host_supports_tls = -1;
29 	if (info->entry_number < host_gdt_entry_tls_min ||  in do_set_thread_area()
30 	    info->entry_number >= host_gdt_entry_tls_min + GDT_ENTRY_TLS_ENTRIES)  in do_set_thread_area()
31 		return -EINVAL;  in do_set_thread_area()
33 	if (using_seccomp) {  in do_set_thread_area()
34 		int idx = info->entry_number - host_gdt_entry_tls_min;  in do_set_thread_area()  local
35 		struct stub_data *data = (void *)task->mm->context.id.stack;  in do_set_thread_area()
37 		data->arch_data.tls[idx] = *info;  in do_set_thread_area()
38 		data->arch_data.sync |= BIT(idx);  in do_set_thread_area()
43 	ret = os_set_thread_area(info, task->mm->context.id.pid);  in do_set_thread_area()
45 	if (ret)  in do_set_thread_area()
47 		       "index = %d\n", ret, info->entry_number);  in do_set_thread_area()
62 	struct thread_struct *t = &task->thread;  in get_free_idx()
63 	int idx;  in get_free_idx()  local
65 	for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)  in get_free_idx()
66 		if (!t->arch.tls_array[idx].present)  in get_free_idx()
67 			return idx + GDT_ENTRY_TLS_MIN;  in get_free_idx()
68 	return -ESRCH;  in get_free_idx()
77 	 * Check the LDT_empty or the i386 sys_get_thread_area code - we obtain  in clear_user_desc()
80 	info->read_exec_only = 1;  in clear_user_desc()
81 	info->seg_not_present = 1;  in clear_user_desc()
89 	int idx;  in load_TLS()  local
91 	for (idx = GDT_ENTRY_TLS_MIN; idx < GDT_ENTRY_TLS_MAX; idx++) {  in load_TLS()
93 			&to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN];  in load_TLS()
96 		 * Actually, now if it wasn't flushed it gets cleared and  in load_TLS()
99 		if (!curr->present) {  in load_TLS()
100 			if (!curr->flushed) {  in load_TLS()
101 				clear_user_desc(&curr->tls);  in load_TLS()
102 				curr->tls.entry_number = idx;  in load_TLS()
104 				WARN_ON(!LDT_empty(&curr->tls));  in load_TLS()
109 		if (!(flags & O_FORCE) && curr->flushed)  in load_TLS()
112 		ret = do_set_thread_area(current, &curr->tls);  in load_TLS()
113 		if (ret)  in load_TLS()
116 		curr->flushed = 1;  in load_TLS()
123  * Verify if we need to do a flush for the new process, i.e. if there are any
124  * present desc's, only if they haven't been flushed.
133 			&task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];  in needs_TLS_update()
136 		 * Can't test curr->present, we may need to clear a descriptor  in needs_TLS_update()
139 		if (curr->flushed)  in needs_TLS_update()
157 			&task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];  in clear_flushed_tls()
160 		 * Still correct to do this, if it wasn't present on the host it  in clear_flushed_tls()
163 		if (!curr->present)  in clear_flushed_tls()
166 		curr->flushed = 0;  in clear_flushed_tls()
171  * In SKAS0 mode, currently, multiple guest threads sharing the same ->mm have a
174  * However, if each thread had a different host process (and this was discussed
177  * And this will not need be used when (and if) we'll add support to the host
183 	if (!host_supports_tls)  in arch_switch_tls()
189 	 * task->mm == NULL, which would cause a crash.  in arch_switch_tls()
191 	if (likely(to->mm))  in arch_switch_tls()
198 			 int idx, int flushed)  in set_tls_entry()  argument
200 	struct thread_struct *t = &task->thread;  in set_tls_entry()
202 	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)  in set_tls_entry()
203 		return -EINVAL;  in set_tls_entry()
205 	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls = *info;  in set_tls_entry()
206 	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present = 1;  in set_tls_entry()
207 	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed = flushed;  in set_tls_entry()
215 	int idx, ret = -EFAULT;  in arch_set_tls()  local
217 	if (copy_from_user(&info, (void __user *) tls, sizeof(info)))  in arch_set_tls()
220 	ret = -EINVAL;  in arch_set_tls()
221 	if (LDT_empty(&info))  in arch_set_tls()
224 	idx = info.entry_number;  in arch_set_tls()
226 	ret = set_tls_entry(new, &info, idx, 0);  in arch_set_tls()
232 			 int idx)  in get_tls_entry()  argument
234 	struct thread_struct *t = &task->thread;  in get_tls_entry()
236 	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)  in get_tls_entry()
237 		return -EINVAL;  in get_tls_entry()
239 	if (!t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present)  in get_tls_entry()
242 	*info = t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls;  in get_tls_entry()
247 	 * flushed. This could be triggered if load_TLS() failed.  in get_tls_entry()
249 	if (unlikely(task == current &&  in get_tls_entry()
250 		     !t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) {  in get_tls_entry()
252 				"without flushed TLS.", current->pid);  in get_tls_entry()
263 	info->entry_number = idx;  in get_tls_entry()
270 	int idx, ret;  in SYSCALL_DEFINE1()  local
272 	if (!host_supports_tls)  in SYSCALL_DEFINE1()
273 		return -ENOSYS;  in SYSCALL_DEFINE1()
275 	if (copy_from_user(&info, user_desc, sizeof(info)))  in SYSCALL_DEFINE1()
276 		return -EFAULT;  in SYSCALL_DEFINE1()
278 	idx = info.entry_number;  in SYSCALL_DEFINE1()
280 	if (idx == -1) {  in SYSCALL_DEFINE1()
281 		idx = get_free_idx(current);  in SYSCALL_DEFINE1()
282 		if (idx < 0)  in SYSCALL_DEFINE1()
283 			return idx;  in SYSCALL_DEFINE1()
284 		info.entry_number = idx;  in SYSCALL_DEFINE1()
286 		if (put_user(idx, &user_desc->entry_number))  in SYSCALL_DEFINE1()
287 			return -EFAULT;  in SYSCALL_DEFINE1()
291 	if (ret)  in SYSCALL_DEFINE1()
293 	return set_tls_entry(current, &info, idx, 1);  in SYSCALL_DEFINE1()
301 int ptrace_set_thread_area(struct task_struct *child, int idx,  in ptrace_set_thread_area()  argument
306 	if (!host_supports_tls)  in ptrace_set_thread_area()
307 		return -EIO;  in ptrace_set_thread_area()
309 	if (copy_from_user(&info, user_desc, sizeof(info)))  in ptrace_set_thread_area()
310 		return -EFAULT;  in ptrace_set_thread_area()
312 	return set_tls_entry(child, &info, idx, 0);  in ptrace_set_thread_area()
318 	int idx, ret;  in SYSCALL_DEFINE1()  local
320 	if (!host_supports_tls)  in SYSCALL_DEFINE1()
321 		return -ENOSYS;  in SYSCALL_DEFINE1()
323 	if (get_user(idx, &user_desc->entry_number))  in SYSCALL_DEFINE1()
324 		return -EFAULT;  in SYSCALL_DEFINE1()
326 	ret = get_tls_entry(current, &info, idx);  in SYSCALL_DEFINE1()
327 	if (ret < 0)  in SYSCALL_DEFINE1()
330 	if (copy_to_user(user_desc, &info, sizeof(info)))  in SYSCALL_DEFINE1()
331 		ret = -EFAULT;  in SYSCALL_DEFINE1()
340 int ptrace_get_thread_area(struct task_struct *child, int idx,  in ptrace_get_thread_area()  argument
346 	if (!host_supports_tls)  in ptrace_get_thread_area()
347 		return -EIO;  in ptrace_get_thread_area()
349 	ret = get_tls_entry(child, &info, idx);  in ptrace_get_thread_area()
350 	if (ret < 0)  in ptrace_get_thread_area()
353 	if (copy_to_user(user_desc, &info, sizeof(info)))  in ptrace_get_thread_area()
354 		ret = -EFAULT;  in ptrace_get_thread_area()
360  * This code is really i386-only, but it detects and logs x86_64 GDT indexes
361  * if a 32-bit UML is running on a 64-bit host.
366 	if (host_supports_tls) {  in __setup_host_supports_tls()