1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright 2020, Sandipan Das, IBM Corp.
4 */
5
6 #ifndef _SELFTESTS_POWERPC_PKEYS_H
7 #define _SELFTESTS_POWERPC_PKEYS_H
8
9 #include <sys/mman.h>
10
11 #include "reg.h"
12 #include "utils.h"
13
14 /*
15 * Older versions of libc use the Intel-specific access rights.
16 * Hence, override the definitions as they might be incorrect.
17 */
18 #undef PKEY_DISABLE_ACCESS
19 #define PKEY_DISABLE_ACCESS 0x3
20
21 #undef PKEY_DISABLE_WRITE
22 #define PKEY_DISABLE_WRITE 0x2
23
24 #undef PKEY_DISABLE_EXECUTE
25 #define PKEY_DISABLE_EXECUTE 0x4
26
27 /* Older versions of libc do not define this */
28 #ifndef SEGV_PKUERR
29 #define SEGV_PKUERR 4
30 #endif
31
32 #define SI_PKEY_OFFSET 0x20
33
34 #define __NR_pkey_mprotect 386
35 #define __NR_pkey_alloc 384
36 #define __NR_pkey_free 385
37
38 #define PKEY_BITS_PER_PKEY 2
39 #define NR_PKEYS 32
40 #define PKEY_BITS_MASK ((1UL << PKEY_BITS_PER_PKEY) - 1)
41
42 inline unsigned long pkeyreg_get(void)
43 {
44 return mfspr(SPRN_AMR);
45 }
46
47 inline void pkeyreg_set(unsigned long amr)
48 {
49 set_amr(amr);
50 }
51
52 void pkey_set_rights(int pkey, unsigned long rights)
53 {
54 unsigned long amr, shift;
55
56 shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
57 amr = pkeyreg_get();
58 amr &= ~(PKEY_BITS_MASK << shift);
59 amr |= (rights & PKEY_BITS_MASK) << shift;
60 pkeyreg_set(amr);
61 }
62
63 int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
64 {
65 return syscall(__NR_pkey_mprotect, addr, len, prot, pkey);
66 }
67
68 int sys_pkey_alloc(unsigned long flags, unsigned long rights)
69 {
70 return syscall(__NR_pkey_alloc, flags, rights);
71 }
72
73 int sys_pkey_free(int pkey)
74 {
75 return syscall(__NR_pkey_free, pkey);
76 }
77
78 int pkeys_unsupported(void)
79 {
80 bool hash_mmu = false;
81 int pkey;
82
83 /* Protection keys are currently supported on Hash MMU only */
84 FAIL_IF(using_hash_mmu(&hash_mmu));
85 SKIP_IF(!hash_mmu);
86
87 /* Check if the system call is supported */
88 pkey = sys_pkey_alloc(0, 0);
89 SKIP_IF(pkey < 0);
90 sys_pkey_free(pkey);
91
92 return 0;
93 }
94
95 int siginfo_pkey(siginfo_t *si)
96 {
97 /*
98 * In older versions of libc, siginfo_t does not have si_pkey as
99 * a member.
100 */
101 #ifdef si_pkey
102 return si->si_pkey;
103 #else
104 return *((int *)(((char *) si) + SI_PKEY_OFFSET));
105 #endif
106 }
107
108 #define pkey_rights(r) ({ \
109 static char buf[4] = "rwx"; \
110 unsigned int amr_bits; \
111 if ((r) & PKEY_DISABLE_EXECUTE) \
112 buf[2] = '-'; \
113 amr_bits = (r) & PKEY_BITS_MASK; \
114 if (amr_bits & PKEY_DISABLE_WRITE) \
115 buf[1] = '-'; \
116 if (amr_bits & PKEY_DISABLE_ACCESS & ~PKEY_DISABLE_WRITE) \
117 buf[0] = '-'; \
118 buf; \
119 })
120
121 unsigned long next_pkey_rights(unsigned long rights)
122 {
123 if (rights == PKEY_DISABLE_ACCESS)
124 return PKEY_DISABLE_EXECUTE;
125 else if (rights == (PKEY_DISABLE_ACCESS | PKEY_DISABLE_EXECUTE))
126 return 0;
127
128 if ((rights & PKEY_BITS_MASK) == 0)
129 rights |= PKEY_DISABLE_WRITE;
130 else if ((rights & PKEY_BITS_MASK) == PKEY_DISABLE_WRITE)
131 rights |= PKEY_DISABLE_ACCESS;
132
133 return rights;
134 }
135
136 #endif /* _SELFTESTS_POWERPC_PKEYS_H */
137
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