1/*
2 * Copyright (c) 2010-2012 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28#include <mach_rt.h>
29#include <mach_debug.h>
30#include <mach_ldebug.h>
31
32#include <mach/kern_return.h>
33#include <mach/mach_traps.h>
34#include <mach/thread_status.h>
35#include <mach/vm_param.h>
36
37#include <kern/counters.h>
38#include <kern/cpu_data.h>
39#include <kern/mach_param.h>
40#include <kern/task.h>
41#include <kern/thread.h>
42#include <kern/sched_prim.h>
43#include <kern/misc_protos.h>
44#include <kern/assert.h>
45#include <kern/debug.h>
46#include <kern/spl.h>
47#include <kern/syscall_sw.h>
48#include <ipc/ipc_port.h>
49#include <vm/vm_kern.h>
50#include <vm/pmap.h>
51
52#include <i386/cpu_number.h>
53#include <i386/eflags.h>
54#include <i386/proc_reg.h>
55#include <i386/tss.h>
56#include <i386/user_ldt.h>
57#include <i386/fpu.h>
58#include <i386/machdep_call.h>
59#include <i386/vmparam.h>
60#include <i386/mp_desc.h>
61#include <i386/misc_protos.h>
62#include <i386/thread.h>
63#include <i386/trap.h>
64#include <i386/seg.h>
65#include <mach/i386/syscall_sw.h>
66#include <sys/syscall.h>
67#include <sys/kdebug.h>
68#include <sys/errno.h>
69#include <../bsd/sys/sysent.h>
70
71
72/*
73 * Duplicate parent state in child
74 * for U**X fork.
75 */
76kern_return_t
77machine_thread_dup(
78    thread_t		parent,
79    thread_t		child
80)
81{
82
83	pcb_t		parent_pcb = THREAD_TO_PCB(parent);
84	pcb_t		child_pcb = THREAD_TO_PCB(child);
85
86	/*
87	 * Copy over the x86_saved_state registers
88	 */
89	if (thread_is_64bit(parent))
90		bcopy(USER_REGS64(parent), USER_REGS64(child), sizeof(x86_saved_state64_t));
91	else
92		bcopy(USER_REGS32(parent), USER_REGS32(child), sizeof(x86_saved_state32_t));
93
94	/*
95	 * Check to see if parent is using floating point
96	 * and if so, copy the registers to the child
97	 */
98	fpu_dup_fxstate(parent, child);
99
100#ifdef	MACH_BSD
101	/*
102	 * Copy the parent's cthread id and USER_CTHREAD descriptor, if 32-bit.
103	 */
104	child_pcb->cthread_self = parent_pcb->cthread_self;
105	if (!thread_is_64bit(parent))
106		child_pcb->cthread_desc = parent_pcb->cthread_desc;
107
108	/*
109	 * FIXME - should a user specified LDT, TSS and V86 info
110	 * be duplicated as well?? - probably not.
111	 */
112	// duplicate any use LDT entry that was set I think this is appropriate.
113        if (parent_pcb->uldt_selector!= 0) {
114	        child_pcb->uldt_selector = parent_pcb->uldt_selector;
115		child_pcb->uldt_desc = parent_pcb->uldt_desc;
116	}
117#endif
118
119	return (KERN_SUCCESS);
120}
121
122void thread_set_parent(thread_t parent, int pid);
123
124void
125thread_set_parent(thread_t parent, int pid)
126{
127	pal_register_cache_state(parent, DIRTY);
128
129	if (thread_is_64bit(parent)) {
130		x86_saved_state64_t	*iss64;
131
132		iss64 = USER_REGS64(parent);
133
134		iss64->rax = pid;
135		iss64->rdx = 0;
136		iss64->isf.rflags &= ~EFL_CF;
137	} else {
138		x86_saved_state32_t	*iss32;
139
140		iss32 = USER_REGS32(parent);
141
142		iss32->eax = pid;
143		iss32->edx = 0;
144		iss32->efl &= ~EFL_CF;
145	}
146}
147
148/*
149 * thread_fast_set_cthread_self: Sets the machine kernel thread ID of the
150 * current thread to the given thread ID; fast version for 32-bit processes
151 *
152 * Parameters:    self                    Thread ID to set
153 *
154 * Returns:        0                      Success
155 *                !0                      Not success
156 */
157kern_return_t
158thread_fast_set_cthread_self(uint32_t self)
159{
160	machine_thread_set_tsd_base(current_thread(), self);
161	return (USER_CTHREAD); /* N.B.: not a kern_return_t! */
162}
163
164/*
165 * thread_fast_set_cthread_self64: Sets the machine kernel thread ID of the
166 * current thread to the given thread ID; fast version for 64-bit processes
167 *
168 * Parameters:    self                    Thread ID
169 *
170 * Returns:        0                      Success
171 *                !0                      Not success
172 */
173kern_return_t
174thread_fast_set_cthread_self64(uint64_t self)
175{
176	machine_thread_set_tsd_base(current_thread(), self);
177	return (USER_CTHREAD); /* N.B.: not a kern_return_t! */
178}
179
180/*
181 * thread_set_user_ldt routine is the interface for the user level
182 * settable ldt entry feature.  allowing a user to create arbitrary
183 * ldt entries seems to be too large of a security hole, so instead
184 * this mechanism is in place to allow user level processes to have
185 * an ldt entry that can be used in conjunction with the FS register.
186 *
187 * Swapping occurs inside the pcb.c file along with initialization
188 * when a thread is created. The basic functioning theory is that the
189 * pcb->uldt_selector variable will contain either 0 meaning the
190 * process has not set up any entry, or the selector to be used in
191 * the FS register. pcb->uldt_desc contains the actual descriptor the
192 * user has set up stored in machine usable ldt format.
193 *
194 * Currently one entry is shared by all threads (USER_SETTABLE), but
195 * this could be changed in the future by changing how this routine
196 * allocates the selector. There seems to be no real reason at this
197 * time to have this added feature, but in the future it might be
198 * needed.
199 *
200 * address is the linear address of the start of the data area size
201 * is the size in bytes of the area flags should always be set to 0
202 * for now. in the future it could be used to set R/W permisions or
203 * other functions. Currently the segment is created as a data segment
204 * up to 1 megabyte in size with full read/write permisions only.
205 *
206 * this call returns the segment selector or -1 if any error occurs
207 */
208kern_return_t
209thread_set_user_ldt(uint32_t address, uint32_t size, uint32_t flags)
210{
211	pcb_t pcb;
212	struct fake_descriptor temp;
213
214	if (flags != 0)
215		return -1;		// flags not supported
216	if (size > 0xFFFFF)
217		return -1;		// size too big, 1 meg is the limit
218
219	mp_disable_preemption();
220
221	// create a "fake" descriptor so we can use fix_desc()
222	// to build a real one...
223	//   32 bit default operation size
224	//   standard read/write perms for a data segment
225	pcb = THREAD_TO_PCB(current_thread());
226	temp.offset = address;
227	temp.lim_or_seg = size;
228	temp.size_or_wdct = SZ_32;
229	temp.access = ACC_P|ACC_PL_U|ACC_DATA_W;
230
231	// turn this into a real descriptor
232	fix_desc(&temp,1);
233
234	// set up our data in the pcb
235	pcb->uldt_desc = *(struct real_descriptor*)&temp;
236	pcb->uldt_selector = USER_SETTABLE;		// set the selector value
237
238	// now set it up in the current table...
239	*ldt_desc_p(USER_SETTABLE) = *(struct real_descriptor*)&temp;
240
241	mp_enable_preemption();
242
243	return USER_SETTABLE;
244}
245