osfmk/i386/bsd_i386_native.c

   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_debug.h>
  29 #include <mach_ldebug.h>
  30
  31 #include <mach/kern_return.h>
  32 #include <mach/mach_traps.h>
  33 #include <mach/thread_status.h>
  34 #include <mach/vm_param.h>
  35
  36 #include <kern/counters.h>
  37 #include <kern/cpu_data.h>
  38 #include <kern/mach_param.h>
  39 #include <kern/task.h>
  40 #include <kern/thread.h>
  41 #include <kern/sched_prim.h>
  42 #include <kern/misc_protos.h>
  43 #include <kern/assert.h>
  44 #include <kern/debug.h>
  45 #include <kern/spl.h>
  46 #include <kern/syscall_sw.h>
  47 #include <ipc/ipc_port.h>
  48 #include <vm/vm_kern.h>
  49 #include <vm/pmap.h>
  50
  51 #include <i386/cpu_number.h>
  52 #include <i386/eflags.h>
  53 #include <i386/proc_reg.h>
  54 #include <i386/tss.h>
  55 #include <i386/user_ldt.h>
  56 #include <i386/fpu.h>
  57 #include <i386/machdep_call.h>
  58 #include <i386/vmparam.h>
  59 #include <i386/mp_desc.h>
  60 #include <i386/misc_protos.h>
  61 #include <i386/thread.h>
  62 #include <i386/trap.h>
  63 #include <i386/seg.h>
  64 #include <mach/i386/syscall_sw.h>
  65 #include <sys/syscall.h>
  66 #include <sys/kdebug.h>
  67 #include <sys/errno.h>
  68 #include <../bsd/sys/sysent.h>
  69
  70
  71 /*
  72  * Duplicate parent state in child
  73  * for U**X fork.
  74  */
  75 kern_return_t
  76 machine_thread_dup(
  77         thread_t            parent,
  78         thread_t            child,
  79         __unused boolean_t  is_corpse
  80         )
  81 {
  82         pcb_t           parent_pcb = THREAD_TO_PCB(parent);
  83         pcb_t           child_pcb = THREAD_TO_PCB(child);
  84
  85         /*
  86          * Copy over the x86_saved_state registers
  87          */
  88         if (thread_is_64bit_addr(parent)) {
  89                 bcopy(USER_REGS64(parent), USER_REGS64(child), sizeof(x86_saved_state64_t));
  90         } else {
  91                 bcopy(USER_REGS32(parent), USER_REGS32(child), sizeof(x86_saved_state32_t));
  92         }
  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_addr(parent)) {
 106                 child_pcb->cthread_desc = parent_pcb->cthread_desc;
 107         }
 108
 109         /*
 110          * FIXME - should a user specified LDT, TSS and V86 info
 111          * be duplicated as well?? - probably not.
 112          */
 113         // duplicate any use LDT entry that was set I think this is appropriate.
 114         if (parent_pcb->uldt_selector != 0) {
 115                 child_pcb->uldt_selector = parent_pcb->uldt_selector;
 116                 child_pcb->uldt_desc = parent_pcb->uldt_desc;
 117         }
 118 #endif
 119
 120         return KERN_SUCCESS;
 121 }
 122
 123 void thread_set_parent(thread_t parent, int pid);
 124
 125 void
 126 thread_set_parent(thread_t parent, int pid)
 127 {
 128         pal_register_cache_state(parent, DIRTY);
 129
 130         if (thread_is_64bit_addr(parent)) {
 131                 x86_saved_state64_t     *iss64;
 132
 133                 iss64 = USER_REGS64(parent);
 134
 135                 iss64->rax = pid;
 136                 iss64->rdx = 0;
 137                 iss64->isf.rflags &= ~EFL_CF;
 138         } else {
 139                 x86_saved_state32_t     *iss32;
 140
 141                 iss32 = USER_REGS32(parent);
 142
 143                 iss32->eax = pid;
 144                 iss32->edx = 0;
 145                 iss32->efl &= ~EFL_CF;
 146         }
 147 }
 148
 149 /*
 150  * thread_fast_set_cthread_self: Sets the machine kernel thread ID of the
 151  * current thread to the given thread ID; fast version for 32-bit processes
 152  *
 153  * Parameters:    self                    Thread ID to set
 154  *
 155  * Returns:        0                      Success
 156  *                !0                      Not success
 157  */
 158 kern_return_t
 159 thread_fast_set_cthread_self(uint32_t self)
 160 {
 161         machine_thread_set_tsd_base(current_thread(), self);
 162         return USER_CTHREAD; /* N.B.: not a kern_return_t! */
 163 }
 164
 165 /*
 166  * thread_fast_set_cthread_self64: Sets the machine kernel thread ID of the
 167  * current thread to the given thread ID; fast version for 64-bit processes
 168  *
 169  * Parameters:    self                    Thread ID
 170  *
 171  * Returns:        0                      Success
 172  *                !0                      Not success
 173  */
 174 kern_return_t
 175 thread_fast_set_cthread_self64(uint64_t self)
 176 {
 177         machine_thread_set_tsd_base(current_thread(), self);
 178         return USER_CTHREAD; /* N.B.: not a kern_return_t! */
 179 }
 180
 181 /*
 182  * thread_set_user_ldt routine is the interface for the user level
 183  * settable ldt entry feature.  allowing a user to create arbitrary
 184  * ldt entries seems to be too large of a security hole, so instead
 185  * this mechanism is in place to allow user level processes to have
 186  * an ldt entry that can be used in conjunction with the FS register.
 187  *
 188  * Swapping occurs inside the pcb.c file along with initialization
 189  * when a thread is created. The basic functioning theory is that the
 190  * pcb->uldt_selector variable will contain either 0 meaning the
 191  * process has not set up any entry, or the selector to be used in
 192  * the FS register. pcb->uldt_desc contains the actual descriptor the
 193  * user has set up stored in machine usable ldt format.
 194  *
 195  * Currently one entry is shared by all threads (USER_SETTABLE), but
 196  * this could be changed in the future by changing how this routine
 197  * allocates the selector. There seems to be no real reason at this
 198  * time to have this added feature, but in the future it might be
 199  * needed.
 200  *
 201  * address is the linear address of the start of the data area size
 202  * is the size in bytes of the area flags should always be set to 0
 203  * for now. in the future it could be used to set R/W permisions or
 204  * other functions. Currently the segment is created as a data segment
 205  * up to 1 megabyte in size with full read/write permisions only.
 206  *
 207  * this call returns the segment selector or -1 if any error occurs
 208  */
 209 kern_return_t
 210 thread_set_user_ldt(uint32_t address, uint32_t size, uint32_t flags)
 211 {
 212         pcb_t pcb;
 213         struct fake_descriptor temp;
 214
 215         if (flags != 0) {
 216                 return -1;              // flags not supported
 217         }
 218         if (size > 0xFFFFF) {
 219                 return -1;              // size too big, 1 meg is the limit
 220         }
 221         mp_disable_preemption();
 222
 223         // create a "fake" descriptor so we can use fix_desc()
 224         // to build a real one...
 225         //   32 bit default operation size
 226         //   standard read/write perms for a data segment
 227         pcb = THREAD_TO_PCB(current_thread());
 228         temp.offset = address;
 229         temp.lim_or_seg = size;
 230         temp.size_or_wdct = SZ_32;
 231         temp.access = ACC_P | ACC_PL_U | ACC_DATA_W;
 232
 233         // turn this into a real descriptor
 234         fix_desc(&temp, 1);
 235
 236         // set up our data in the pcb
 237         pcb->uldt_desc = *(struct real_descriptor*)&temp;
 238         pcb->uldt_selector = USER_SETTABLE;             // set the selector value
 239
 240         // now set it up in the current table...
 241         *ldt_desc_p(USER_SETTABLE) = *(struct real_descriptor*)&temp;
 242
 243         mp_enable_preemption();
 244
 245         return USER_SETTABLE;
 246 }