1 //===---- arm_cmse.h - Arm CMSE support -----------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef __ARM_CMSE_H
10 #define __ARM_CMSE_H
11
12 #if (__ARM_FEATURE_CMSE & 0x1)
13 #include <stddef.h>
14 #include <stdint.h>
15
16 #define __ARM_CMSE_SECURE_MODE (__ARM_FEATURE_CMSE & 0x2)
17 #define CMSE_MPU_READWRITE 1 /* checks if readwrite_ok field is set */
18 #define CMSE_AU_NONSECURE 2 /* checks if permissions have secure field unset */
19 #define CMSE_MPU_UNPRIV 4 /* sets T flag on TT insrtuction */
20 #define CMSE_MPU_READ 8 /* checks if read_ok field is set */
21 #define CMSE_MPU_NONSECURE 16 /* sets A flag, checks if secure field unset */
22 #define CMSE_NONSECURE (CMSE_AU_NONSECURE | CMSE_MPU_NONSECURE)
23
24 #define cmse_check_pointed_object(p, f) \
25 cmse_check_address_range((p), sizeof(*(p)), (f))
26
27 #if defined(__cplusplus)
28 extern "C" {
29 #endif
30
31 typedef union {
32 struct cmse_address_info {
33 #ifdef __ARM_BIG_ENDIAN
34 /* __ARM_BIG_ENDIAN */
35 #if (__ARM_CMSE_SECURE_MODE)
36 unsigned idau_region : 8;
37 unsigned idau_region_valid : 1;
38 unsigned secure : 1;
39 unsigned nonsecure_readwrite_ok : 1;
40 unsigned nonsecure_read_ok : 1;
41 #else
42 unsigned : 12;
43 #endif
44 unsigned readwrite_ok : 1;
45 unsigned read_ok : 1;
46 #if (__ARM_CMSE_SECURE_MODE)
47 unsigned sau_region_valid : 1;
48 #else
49 unsigned : 1;
50 #endif
51 unsigned mpu_region_valid : 1;
52 #if (__ARM_CMSE_SECURE_MODE)
53 unsigned sau_region : 8;
54 #else
55 unsigned : 8;
56 #endif
57 unsigned mpu_region : 8;
58
59 #else /* __ARM_LITTLE_ENDIAN */
60 unsigned mpu_region : 8;
61 #if (__ARM_CMSE_SECURE_MODE)
62 unsigned sau_region : 8;
63 #else
64 unsigned : 8;
65 #endif
66 unsigned mpu_region_valid : 1;
67 #if (__ARM_CMSE_SECURE_MODE)
68 unsigned sau_region_valid : 1;
69 #else
70 unsigned : 1;
71 #endif
72 unsigned read_ok : 1;
73 unsigned readwrite_ok : 1;
74 #if (__ARM_CMSE_SECURE_MODE)
75 unsigned nonsecure_read_ok : 1;
76 unsigned nonsecure_readwrite_ok : 1;
77 unsigned secure : 1;
78 unsigned idau_region_valid : 1;
79 unsigned idau_region : 8;
80 #else
81 unsigned : 12;
82 #endif
83 #endif /*__ARM_LITTLE_ENDIAN */
84 } flags;
85 unsigned value;
86 } cmse_address_info_t;
87
88 static cmse_address_info_t __attribute__((__always_inline__, __nodebug__))
cmse_TT(void * __p)89 cmse_TT(void *__p) {
90 cmse_address_info_t __u;
91 __u.value = __builtin_arm_cmse_TT(__p);
92 return __u;
93 }
94 static cmse_address_info_t __attribute__((__always_inline__, __nodebug__))
cmse_TTT(void * __p)95 cmse_TTT(void *__p) {
96 cmse_address_info_t __u;
97 __u.value = __builtin_arm_cmse_TTT(__p);
98 return __u;
99 }
100
101 #if __ARM_CMSE_SECURE_MODE
102 static cmse_address_info_t __attribute__((__always_inline__, __nodebug__))
cmse_TTA(void * __p)103 cmse_TTA(void *__p) {
104 cmse_address_info_t __u;
105 __u.value = __builtin_arm_cmse_TTA(__p);
106 return __u;
107 }
108 static cmse_address_info_t __attribute__((__always_inline__, __nodebug__))
cmse_TTAT(void * __p)109 cmse_TTAT(void *__p) {
110 cmse_address_info_t __u;
111 __u.value = __builtin_arm_cmse_TTAT(__p);
112 return __u;
113 }
114 #endif
115
116 #define cmse_TT_fptr(p) cmse_TT(__builtin_bit_cast(void *, (p)))
117 #define cmse_TTT_fptr(p) cmse_TTT(__builtin_bit_cast(void *, (p)))
118
119 #if __ARM_CMSE_SECURE_MODE
120 #define cmse_TTA_fptr(p) cmse_TTA(__builtin_bit_cast(void *, (p)))
121 #define cmse_TTAT_fptr(p) cmse_TTAT(__builtin_bit_cast(void *, (p)))
122 #endif
123
124 static void *__attribute__((__always_inline__))
cmse_check_address_range(void * __pb,size_t __s,int __flags)125 cmse_check_address_range(void *__pb, size_t __s, int __flags) {
126 uintptr_t __begin = (uintptr_t)__pb;
127 uintptr_t __end = __begin + __s - 1;
128
129 if (__end < __begin)
130 return NULL; /* wrap around check */
131
132 /* Check whether the range crosses a 32-bytes aligned address */
133 const int __single_check = (__begin ^ __end) < 0x20u;
134
135 /* execute the right variant of the TT instructions */
136 void *__pe = (void *)__end;
137 cmse_address_info_t __permb, __perme;
138 switch (__flags & (CMSE_MPU_UNPRIV | CMSE_MPU_NONSECURE)) {
139 case 0:
140 __permb = cmse_TT(__pb);
141 __perme = __single_check ? __permb : cmse_TT(__pe);
142 break;
143 case CMSE_MPU_UNPRIV:
144 __permb = cmse_TTT(__pb);
145 __perme = __single_check ? __permb : cmse_TTT(__pe);
146 break;
147 #if __ARM_CMSE_SECURE_MODE
148 case CMSE_MPU_NONSECURE:
149 __permb = cmse_TTA(__pb);
150 __perme = __single_check ? __permb : cmse_TTA(__pe);
151 break;
152 case CMSE_MPU_UNPRIV | CMSE_MPU_NONSECURE:
153 __permb = cmse_TTAT(__pb);
154 __perme = __single_check ? __permb : cmse_TTAT(__pe);
155 break;
156 #endif
157 /* if CMSE_NONSECURE is specified w/o __ARM_CMSE_SECURE_MODE */
158 default:
159 return NULL;
160 }
161
162 /* check that the range does not cross MPU, SAU, or IDAU region boundaries */
163 if (__permb.value != __perme.value)
164 return NULL;
165 #if !(__ARM_CMSE_SECURE_MODE)
166 /* CMSE_AU_NONSECURE is only supported when __ARM_FEATURE_CMSE & 0x2 */
167 if (__flags & CMSE_AU_NONSECURE)
168 return NULL;
169 #endif
170
171 /* check the permission on the range */
172 switch (__flags & ~(CMSE_MPU_UNPRIV | CMSE_MPU_NONSECURE)) {
173 #if (__ARM_CMSE_SECURE_MODE)
174 case CMSE_MPU_READ | CMSE_MPU_READWRITE | CMSE_AU_NONSECURE:
175 case CMSE_MPU_READWRITE | CMSE_AU_NONSECURE:
176 return __permb.flags.nonsecure_readwrite_ok ? __pb : NULL;
177
178 case CMSE_MPU_READ | CMSE_AU_NONSECURE:
179 return __permb.flags.nonsecure_read_ok ? __pb : NULL;
180
181 case CMSE_AU_NONSECURE:
182 return __permb.flags.secure ? NULL : __pb;
183 #endif
184 case CMSE_MPU_READ | CMSE_MPU_READWRITE:
185 case CMSE_MPU_READWRITE:
186 return __permb.flags.readwrite_ok ? __pb : NULL;
187
188 case CMSE_MPU_READ:
189 return __permb.flags.read_ok ? __pb : NULL;
190
191 default:
192 return NULL;
193 }
194 }
195
196 #if __ARM_CMSE_SECURE_MODE
197 static int __attribute__((__always_inline__, __nodebug__))
cmse_nonsecure_caller(void)198 cmse_nonsecure_caller(void) {
199 return !((uintptr_t)__builtin_return_address(0) & 1);
200 }
201
202 #define cmse_nsfptr_create(p) \
203 __builtin_bit_cast(__typeof__(p), \
204 (__builtin_bit_cast(uintptr_t, p) & ~(uintptr_t)1))
205
206 #define cmse_is_nsfptr(p) ((__builtin_bit_cast(uintptr_t, p) & 1) == 0)
207
208 #endif /* __ARM_CMSE_SECURE_MODE */
209
210 void __attribute__((__noreturn__)) cmse_abort(void);
211 #if defined(__cplusplus)
212 }
213 #endif
214
215 #endif /* (__ARM_FEATURE_CMSE & 0x1) */
216
217 #endif /* __ARM_CMSE_H */
218