osfmk/arm64/pinst.s

   1 /*
   2  * Copyright (c) 2016 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
  29 #include <pexpert/arm64/board_config.h>
  30 #include <arm64/proc_reg.h>
  31
  32 /*
  33  * Compare two instructions with constant, spin on mismatch.
  34  *   arg0 - Constant scratch register
  35  *   arg1 - Instruction address scratch register
  36  *   arg2 - Instruction location
  37  *   arg3 - Instruction constant
  38  */
  39 .macro check_instruction
  40         // construct 64-bit constant inline to make sure it is non-executable
  41         movz    $0, #(($3 >> 48) & 0xffff), lsl #48
  42         movk    $0, #(($3 >> 32) & 0xffff), lsl #32
  43         movk    $0, #(($3 >> 16) & 0xffff), lsl #16
  44         movk    $0, #(($3) & 0xffff)
  45         // fetch instructions from "untrusted" memory
  46         adrp    $1, $2@page
  47         add             $1, $1, $2@pageoff
  48         ldr             $1, [$1]
  49         // spin forever if we do not find what we expect
  50         cmp             $0, $1
  51         b.ne    .
  52 .endmacro
  53
  54 #if defined(KERNEL_INTEGRITY_KTRR)
  55
  56 /* AMCC only KTRR protected text, non-executable once the MMU is enabled */
  57         .text
  58         .section        __LAST,__pinst
  59         .align 2
  60
  61 __pinst_set_ttbr1:
  62         msr             TTBR1_EL1, x0
  63         ret
  64
  65 __pinst_set_vbar:
  66         msr             VBAR_EL1, x0
  67         ret
  68
  69 __pinst_set_tcr:
  70         msr             TCR_EL1, x0
  71         ret
  72
  73         .globl _pinst_set_sctlr_trap_addr
  74 __pinst_set_sctlr:
  75         msr             SCTLR_EL1, x0
  76 _pinst_set_sctlr_trap_addr:
  77         ret
  78
  79
  80 /* MMU and AMCC KTRR protected text */
  81         .text
  82         .section        __TEXT_EXEC,__text
  83         .align 2
  84
  85         .globl _pinst_set_ttbr1
  86 _pinst_set_ttbr1:
  87         check_instruction x2, x3, __pinst_set_ttbr1, 0xd65f03c0d5182020
  88         b __pinst_set_ttbr1
  89
  90         .globl _pinst_set_vbar
  91 _pinst_set_vbar:
  92         check_instruction x2, x3, __pinst_set_vbar, 0xd65f03c0d518c000
  93         b __pinst_set_vbar
  94
  95         .globl _pinst_set_tcr
  96 _pinst_set_tcr:
  97         check_instruction x2, x3, __pinst_set_tcr, 0xd65f03c0d5182040
  98         b __pinst_set_tcr
  99
 100         .globl _pinst_set_sctlr
 101 _pinst_set_sctlr:
 102         check_instruction x2, x3, __pinst_set_sctlr, 0xd65f03c0d5181000
 103         b __pinst_set_sctlr
 104
 105 #endif /* defined(KERNEL_INTEGRITY_KTRR) */
 106
 107 #if defined(KERNEL_INTEGRITY_KTRR)
 108
 109         .text
 110         .section        __LAST,__pinst
 111         .align 2
 112
 113 __pinst_spsel_1:
 114         msr             SPSel, #1
 115         ret
 116
 117         .text
 118         .section        __TEXT_EXEC,__text
 119         .align 2
 120
 121         .globl _pinst_spsel_1
 122 _pinst_spsel_1:
 123         check_instruction x2, x3, __pinst_spsel_1, 0xd65f03c0d50041bf
 124         b __pinst_spsel_1
 125
 126 #endif /* defined(KERNEL_INTEGRITY_KTRR)*/
 127