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_ldebug.h>
29
30 #include <mach/kern_return.h>
31 #include <mach/mach_traps.h>
32 #include <mach/thread_status.h>
33 #include <mach/vm_param.h>
34
35 #include <kern/cpu_data.h>
36 #include <kern/mach_param.h>
37 #include <kern/task.h>
38 #include <kern/thread.h>
39 #include <kern/sched_prim.h>
40 #include <kern/misc_protos.h>
41 #include <kern/assert.h>
42 #include <kern/debug.h>
43 #include <kern/spl.h>
44 #include <kern/syscall_sw.h>
45 #include <ipc/ipc_port.h>
46 #include <vm/vm_kern.h>
47 #include <vm/pmap.h>
48
49 #include <i386/cpu_number.h>
50 #include <i386/eflags.h>
51 #include <i386/proc_reg.h>
52 #include <i386/tss.h>
53 #include <i386/user_ldt.h>
54 #include <i386/fpu.h>
55 #include <i386/machdep_call.h>
56 #include <i386/vmparam.h>
57 #include <i386/mp_desc.h>
58 #include <i386/misc_protos.h>
59 #include <i386/thread.h>
60 #include <i386/trap.h>
61 #include <i386/seg.h>
62 #include <mach/i386/syscall_sw.h>
63 #include <sys/syscall.h>
64 #include <sys/kdebug.h>
65 #include <sys/errno.h>
66 #include <../bsd/sys/sysent.h>
67
68
69 /*
70 * Duplicate parent state in child
71 * for U**X fork.
72 */
73 kern_return_t
machine_thread_dup(thread_t parent,thread_t child,__unused boolean_t is_corpse)74 machine_thread_dup(
75 thread_t parent,
76 thread_t child,
77 __unused boolean_t is_corpse
78 )
79 {
80 pcb_t parent_pcb = THREAD_TO_PCB(parent);
81 pcb_t child_pcb = THREAD_TO_PCB(child);
82
83 /*
84 * Copy over the x86_saved_state registers
85 */
86 if (thread_is_64bit_addr(parent)) {
87 bcopy(USER_REGS64(parent), USER_REGS64(child), sizeof(x86_saved_state64_t));
88 } else {
89 bcopy(USER_REGS32(parent), USER_REGS32(child), sizeof(x86_saved_state32_t));
90 }
91
92 /*
93 * Check to see if parent is using floating point
94 * and if so, copy the registers to the child
95 */
96 fpu_dup_fxstate(parent, child);
97
98 #ifdef MACH_BSD
99 /*
100 * Copy the parent's cthread id and USER_CTHREAD descriptor, if 32-bit.
101 */
102 child_pcb->cthread_self = parent_pcb->cthread_self;
103 if (!thread_is_64bit_addr(parent)) {
104 child_pcb->cthread_desc = parent_pcb->cthread_desc;
105 }
106
107 /*
108 * FIXME - should a user specified LDT, TSS and V86 info
109 * be duplicated as well?? - probably not.
110 */
111 // duplicate any use LDT entry that was set I think this is appropriate.
112 if (parent_pcb->uldt_selector != 0) {
113 child_pcb->uldt_selector = parent_pcb->uldt_selector;
114 child_pcb->uldt_desc = parent_pcb->uldt_desc;
115 }
116 #endif
117
118 return KERN_SUCCESS;
119 }
120
121 void thread_set_parent(thread_t parent, int pid);
122
123 void
thread_set_parent(thread_t parent,int pid)124 thread_set_parent(thread_t parent, int pid)
125 {
126 pal_register_cache_state(parent, DIRTY);
127
128 if (thread_is_64bit_addr(parent)) {
129 x86_saved_state64_t *iss64;
130
131 iss64 = USER_REGS64(parent);
132
133 iss64->rax = pid;
134 iss64->rdx = 0;
135 iss64->isf.rflags &= ~EFL_CF;
136 } else {
137 x86_saved_state32_t *iss32;
138
139 iss32 = USER_REGS32(parent);
140
141 iss32->eax = pid;
142 iss32->edx = 0;
143 iss32->efl &= ~EFL_CF;
144 }
145 }
146
147 /*
148 * thread_fast_set_cthread_self: Sets the machine kernel thread ID of the
149 * current thread to the given thread ID; fast version for 32-bit processes
150 *
151 * Parameters: self Thread ID to set
152 *
153 * Returns: 0 Success
154 * !0 Not success
155 */
156 kern_return_t
thread_fast_set_cthread_self(uint32_t self)157 thread_fast_set_cthread_self(uint32_t self)
158 {
159 machine_thread_set_tsd_base(current_thread(), self);
160 return USER_CTHREAD; /* N.B.: not a kern_return_t! */
161 }
162
163 /*
164 * thread_fast_set_cthread_self64: Sets the machine kernel thread ID of the
165 * current thread to the given thread ID; fast version for 64-bit processes
166 *
167 * Parameters: self Thread ID
168 *
169 * Returns: 0 Success
170 * !0 Not success
171 */
172 kern_return_t
thread_fast_set_cthread_self64(uint64_t self)173 thread_fast_set_cthread_self64(uint64_t self)
174 {
175 machine_thread_set_tsd_base(current_thread(), self);
176 return USER_CTHREAD; /* N.B.: not a kern_return_t! */
177 }
178
179 /*
180 * thread_set_user_ldt routine is the interface for the user level
181 * settable ldt entry feature. allowing a user to create arbitrary
182 * ldt entries seems to be too large of a security hole, so instead
183 * this mechanism is in place to allow user level processes to have
184 * an ldt entry that can be used in conjunction with the FS register.
185 *
186 * Swapping occurs inside the pcb.c file along with initialization
187 * when a thread is created. The basic functioning theory is that the
188 * pcb->uldt_selector variable will contain either 0 meaning the
189 * process has not set up any entry, or the selector to be used in
190 * the FS register. pcb->uldt_desc contains the actual descriptor the
191 * user has set up stored in machine usable ldt format.
192 *
193 * Currently one entry is shared by all threads (USER_SETTABLE), but
194 * this could be changed in the future by changing how this routine
195 * allocates the selector. There seems to be no real reason at this
196 * time to have this added feature, but in the future it might be
197 * needed.
198 *
199 * address is the linear address of the start of the data area size
200 * is the size in bytes of the area flags should always be set to 0
201 * for now. in the future it could be used to set R/W permisions or
202 * other functions. Currently the segment is created as a data segment
203 * up to 1 megabyte in size with full read/write permisions only.
204 *
205 * this call returns the segment selector or -1 if any error occurs
206 */
207 kern_return_t
thread_set_user_ldt(uint32_t address,uint32_t size,uint32_t flags)208 thread_set_user_ldt(uint32_t address, uint32_t size, uint32_t flags)
209 {
210 pcb_t pcb;
211 struct fake_descriptor temp;
212
213 if (flags != 0) {
214 return -1; // flags not supported
215 }
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