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 )
  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(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          * Check to see if parent is using floating point
  95          * and if so, copy the registers to the child
  96          */
  97         fpu_dup_fxstate(parent, child);
  98
  99 #ifdef  MACH_BSD
 100         /*
 101          * Copy the parent's cthread id and USER_CTHREAD descriptor, if 32-bit.
 102          */
 103         child_pcb->cthread_self = parent_pcb->cthread_self;
 104         if (!thread_is_64bit(parent))
 105                 child_pcb->cthread_desc = parent_pcb->cthread_desc;
 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
 124 thread_set_parent(thread_t parent, int pid)
 125 {
 126         pal_register_cache_state(parent, DIRTY);
 127
 128         if (thread_is_64bit(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
 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
 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
 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         if (size > 0xFFFFF)
 216                 return -1;              // size too big, 1 meg is the limit
 217
 218         mp_disable_preemption();
 219
 220         // create a "fake" descriptor so we can use fix_desc()
 221         // to build a real one...
 222         //   32 bit default operation size
 223         //   standard read/write perms for a data segment
 224         pcb = THREAD_TO_PCB(current_thread());
 225         temp.offset = address;
 226         temp.lim_or_seg = size;
 227         temp.size_or_wdct = SZ_32;
 228         temp.access = ACC_P|ACC_PL_U|ACC_DATA_W;
 229
 230         // turn this into a real descriptor
 231         fix_desc(&temp,1);
 232
 233         // set up our data in the pcb
 234         pcb->uldt_desc = *(struct real_descriptor*)&temp;
 235         pcb->uldt_selector = USER_SETTABLE;             // set the selector value
 236
 237         // now set it up in the current table...
 238         *ldt_desc_p(USER_SETTABLE) = *(struct real_descriptor*)&temp;
 239
 240         mp_enable_preemption();
 241
 242         return USER_SETTABLE;
 243 }