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 <arm64/proc_reg.h>
 30  #include <pexpert/arm64/board_config.h>
 31  #include "assym.s"
 32  
 33  #ifndef __ASSEMBLER__
 34  #error "This header should only be used in .s files"
 35  #endif
 36  
 37  /**
 38   * Loads the following values from the thread_kernel_state pointer in x0:
 39   *
 40   * x1: $x0->ss_64.pc
 41   * w2: $x0->ss_64.cpsr
 42   * x16: $x0->ss_64.x16
 43   * x17: $x0->ss_64.x17
 44   * lr: $x0->ss_64.lr
 45   *
 46   * On CPUs with PAC support, this macro will auth the above values with ml_check_signed_state().
 47   *
 48   * tmp1 - scratch register 1
 49   * tmp2 - scratch register 2
 50   * tmp3 - scratch register 3
 51   * tmp4 - scratch register 4
 52   * tmp5 - scratch register 5
 53   */
 54  /* BEGIN IGNORE CODESTYLE */
 55  .macro AUTH_THREAD_STATE_IN_X0_COMMON tmp1, tmp2, tmp3, tmp4, tmp5, el0_state_allowed=0, PC_OFF=SS64_PC, CPSR_OFF=SS64_CPSR, X16_OFF=SS64_X16, LR_OFF=SS64_LR, check_func=ml_check_signed_state
 56  	ldr		w2, [x0, \CPSR_OFF]
 57  .if \el0_state_allowed==0
 58  #if __has_feature(ptrauth_calls)
 59  	// If testing for a canary CPSR value, ensure that we do not observe writes to other fields without it
 60  	dmb		ld
 61  #endif
 62  .endif
 63  	ldr		x1, [x0, \PC_OFF]
 64  	ldp		x16, x17, [x0, \X16_OFF]
 65  
 66  #if defined(HAS_APPLE_PAC)
 67  	// Save x3-x5 to preserve across call
 68  	mov		\tmp3, x3
 69  	mov		\tmp4, x4
 70  	mov		\tmp5, x5
 71  
 72  	/*
 73  	* Arg0: The ARM context pointer (already in x0)
 74  	* Arg1: PC to check (loaded above)
 75  	* Arg2: CPSR to check (loaded above)
 76  	* Arg3: the LR to check
 77  	*
 78  	* Stash saved state PC and CPSR in other registers to avoid reloading potentially unauthed
 79  	* values from memory.  (ml_check_signed_state will clobber x1 and x2.)
 80  	*/
 81  	mov		\tmp1, x1
 82  	mov		\tmp2, x2
 83  	ldr		x3, [x0, \LR_OFF]
 84  	mov		x4, x16
 85  	mov		x5, x17
 86  	bl		EXT(\check_func)
 87  	mov		x1, \tmp1
 88  	mov		x2, \tmp2
 89  
 90  .if \el0_state_allowed==0
 91  	and		\tmp2, \tmp2, #PSR64_MODE_MASK
 92  	cbnz		\tmp2, 1f
 93  	bl		EXT(ml_auth_thread_state_invalid_cpsr)
 94  1:
 95  .endif
 96  
 97  	// LR was already loaded/authed earlier, if we reload it we might be loading a potentially unauthed value
 98  	mov		lr, x3
 99  	mov		x3, \tmp3
100  	mov		x4, \tmp4
101  	mov		x5, \tmp5
102  #else
103  	ldr		lr, [x0, \LR_OFF]
104  #endif /* defined(HAS_APPLE_PAC) */
105  .endmacro
106  
107  .macro  AUTH_THREAD_STATE_IN_X0 tmp1, tmp2, tmp3, tmp4, tmp5, el0_state_allowed=0
108  	AUTH_THREAD_STATE_IN_X0_COMMON \tmp1, \tmp2, \tmp3, \tmp4, \tmp5, \el0_state_allowed
109  .endmacro
110  
111  .macro  AUTH_KERNEL_THREAD_STATE_IN_X0 tmp1, tmp2, tmp3, tmp4, tmp5, el0_state_allowed=0
112  	AUTH_THREAD_STATE_IN_X0_COMMON \tmp1, \tmp2, \tmp3, \tmp4, \tmp5, \el0_state_allowed, SS64_KERNEL_PC, SS64_KERNEL_CPSR, SS64_KERNEL_X16, SS64_KERNEL_LR, ml_check_kernel_signed_state
113  .endmacro
114  /* END IGNORE CODESTYLE */
115  
116  /* vim: set ft=asm: */