xref: /xnu-12377.61.12/osfmk/arm/trap.h (revision 4d495c6e23c53686cf65f45067f79024cf5dcee8)
1 /*
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8  * Version 2.0 (the 'License'). You may not use this file except in
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28 /*
29  * @OSF_COPYRIGHT@
30  */
31 /*
32  * Mach Operating System
33  * Copyright (c) 1991,1990 Carnegie Mellon University
34  * All Rights Reserved.
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36  * Permission to use, copy, modify and distribute this software and its
37  * documentation is hereby granted, provided that both the copyright
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40  * thereof, and that both notices appear in supporting documentation.
41  *
42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45  *
46  * Carnegie Mellon requests users of this software to return to
47  *
48  *  Software Distribution Coordinator  or  [email protected]
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52  *
53  * any improvements or extensions that they make and grant Carnegie Mellon
54  * the rights to redistribute these changes.
55  */
56 /*
57  */
58 
59 #ifndef _ARM_TRAP_H_
60 #define _ARM_TRAP_H_
61 
62 /*
63  * Hardware trap vectors for ARM.
64  */
65 
66 #define T_RESET                 0
67 #define T_UNDEF                 1
68 #define T_SWI                   2
69 #define T_PREFETCH_ABT          3
70 #define T_DATA_ABT              4
71 #define T_IRQ                   6
72 #define T_FIQ                   7
73 #define T_PMU                   8
74 
75 
76 #define TRAP_NAMES "reset", "undefined instruction", "software interrupt", \
77 	           "prefetch abort", "data abort", "irq interrupt", \
78 	           "fast interrupt", "perfmon"
79 
80 /*
81  * Page-fault trap codes.
82  */
83 #define T_PF_PROT               0x1             /* protection violation */
84 #define T_PF_WRITE              0x2             /* write access */
85 #define T_PF_USER               0x4             /* from user state */
86 
87 #if !defined(ASSEMBLER)
88 
89 #if __arm64__
90 #define ML_TRAP_REGISTER_1      "x8"
91 #define ML_TRAP_REGISTER_2      "x16"
92 #define ML_TRAP_REGISTER_3      "x17"
93 #else
94 #define ML_TRAP_REGISTER_1      "r8"
95 #define ML_TRAP_REGISTER_2      "r0"
96 #define ML_TRAP_REGISTER_3      "r1"
97 #endif
98 
99 #define ml_recoverable_trap(code) \
100 	__asm__ volatile ("brk #%0" : : "i"(code))
101 
102 #if __has_builtin(__builtin_arm_trap)
103 #define ml_fatal_trap(code) ({ \
104 	__builtin_arm_trap(code); \
105 	__builtin_unreachable(); \
106 })
107 #else
108 #define ml_fatal_trap(code)  ({ \
109 	ml_recoverable_trap(code); \
110 	__builtin_unreachable(); \
111 })
112 #endif
113 
114 #if defined(XNU_KERNEL_PRIVATE)
115 /*
116  * Unfortunately brk instruction only takes constant, so we have to unroll all the
117  * cases and let compiler do the real work.  ¯\_(ツ)_/¯
118  *
119  * Codegen should be clean due to inlining which enables constant-folding.
120  */
121 #define TRAP_CASE(code) \
122 	case code: \
123 	    ml_fatal_trap(0x5500 + code);
124 
125 #define TRAP_5CASES(code) \
126 	TRAP_CASE(code) \
127 	TRAP_CASE(code + 1) \
128 	TRAP_CASE(code + 2) \
129 	TRAP_CASE(code + 3) \
130 	TRAP_CASE(code + 4)
131 
132 /* For use by clang option -ftrap-function only */
133 __attribute__((cold, always_inline))
134 static inline void
ml_bound_chk_soft_trap(unsigned char code)135 ml_bound_chk_soft_trap(unsigned char code)
136 {
137 	switch (code) {
138 		/* 0 ~ 24 */
139 		TRAP_5CASES(0)
140 		TRAP_5CASES(5)
141 		TRAP_5CASES(10)
142 		TRAP_5CASES(15)
143 		TRAP_5CASES(20)
144 	case 25:         /* Bound check */
145 		/* code defined in kern/telemetry.h */
146 #if BOUND_CHECKS_DEBUG
147 		/*
148 		 * ml_recoverable_trap ensures that we get a separate trap instruction
149 		 * for each compiler-added check, and in BOUND_CHECKS_DEBUG we use it
150 		 * with the the fatal 0x5500 trap code. This makes it easier to
151 		 * understand what failed when you develop at desk.
152 		 */
153 		ml_recoverable_trap(0x5500 + 25);
154 #else /* BOUND_CHECKS_DEBUG */
155 		ml_recoverable_trap(0xFF00 + 25);
156 #endif /* BOUND_CHECKS_DEBUG */
157 		break;
158 	default:
159 		ml_fatal_trap(0x0);
160 	}
161 }
162 #endif /* XNU_KERNEL_PRIVATE */
163 #endif /* !ASSEMBLER */
164 
165 #endif  /* _ARM_TRAP_H_ */
166