osfmk/arm64/machine_routines_asm.h

   1 /*
   2  * Copyright (c) 2019 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 "assym.s"
  31
  32 #ifndef __ASSEMBLER__
  33 #error "This header should only be used in .s files"
  34 #endif
  35
  36 /**
  37  * Loads the following values from the thread_kernel_state pointer in x0:
  38  *
  39  * x1: $x0->ss_64.pc
  40  * w2: $x0->ss_64.cpsr
  41  * x16: $x0->ss_64.x16
  42  * x17: $x0->ss_64.x17
  43  * lr: $x0->ss_64.lr
  44  *
  45  * On CPUs with PAC support, this macro will auth the above values with ml_check_signed_state().
  46  *
  47  * arg0 - scratch register 1
  48  * arg1 - scratch register 2
  49  * arg2 - scratch register 3
  50  * arg3 - scratch register 4
  51  * arg4 - scratch register 5
  52  */
  53 /* BEGIN IGNORE CODESTYLE */
  54 .macro  AUTH_THREAD_STATE_IN_X0
  55         ldr             x1, [x0, SS64_PC]
  56         ldr             w2, [x0, SS64_CPSR]
  57         ldp             x16, x17, [x0, SS64_X16]
  58
  59 #if defined(HAS_APPLE_PAC)
  60         // Save x3-x5 to preserve across call
  61         mov             $2, x3
  62         mov             $3, x4
  63         mov             $4, x5
  64
  65         /*
  66         * Arg0: The ARM context pointer (already in x0)
  67         * Arg1: PC to check (loaded above)
  68         * Arg2: CPSR to check (loaded above)
  69         * Arg3: the LR to check
  70         *
  71         * Stash saved state PC and CPSR in other registers to avoid reloading potentially unauthed
  72         * values from memory.  (ml_check_signed_state will clobber x1 and x2.)
  73         */
  74         mov             $0, x1
  75         mov             $1, x2
  76         ldr             x3, [x0, SS64_LR]
  77         mov             x4, x16
  78         mov             x5, x17
  79         bl              EXT(ml_check_signed_state)
  80         mov             x1, $0
  81         mov             x2, $1
  82
  83         // LR was already loaded/authed earlier, if we reload it we might be loading a potentially unauthed value
  84         mov             lr, x3
  85         mov             x3, $2
  86         mov             x4, $3
  87         mov             x5, $4
  88 #else
  89         ldr             lr, [x0, SS64_LR]
  90 #endif /* defined(HAS_APPLE_PAC) */
  91 .endmacro
  92 /* END IGNORE CODESTYLE */
  93
  94 /* vim: set ft=asm: */