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 #ifndef NT_PPC_PKEY
39 #define NT_PPC_PKEY 0x110
40 #endif
41
42 #define PKEY_BITS_PER_PKEY 2
43 #define NR_PKEYS 32
44 #define PKEY_BITS_MASK ((1UL << PKEY_BITS_PER_PKEY) - 1)
45
46 #define AMR_BITS_PER_PKEY 2
47 #define PKEY_REG_BITS (sizeof(u64) * 8)
48 #define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey + 1) * AMR_BITS_PER_PKEY))
49
pkeyreg_get(void)50 inline unsigned long pkeyreg_get(void)
51 {
52 return mfspr(SPRN_AMR);
53 }
54
pkeyreg_set(unsigned long amr)55 inline void pkeyreg_set(unsigned long amr)
56 {
57 set_amr(amr);
58 }
59
pkey_set_rights(int pkey,unsigned long rights)60 void pkey_set_rights(int pkey, unsigned long rights)
61 {
62 unsigned long amr, shift;
63
64 shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
65 amr = pkeyreg_get();
66 amr &= ~(PKEY_BITS_MASK << shift);
67 amr |= (rights & PKEY_BITS_MASK) << shift;
68 pkeyreg_set(amr);
69 }
70
sys_pkey_mprotect(void * addr,size_t len,int prot,int pkey)71 int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
72 {
73 return syscall(__NR_pkey_mprotect, addr, len, prot, pkey);
74 }
75
sys_pkey_alloc(unsigned long flags,unsigned long rights)76 int sys_pkey_alloc(unsigned long flags, unsigned long rights)
77 {
78 return syscall(__NR_pkey_alloc, flags, rights);
79 }
80
sys_pkey_free(int pkey)81 int sys_pkey_free(int pkey)
82 {
83 return syscall(__NR_pkey_free, pkey);
84 }
85
pkeys_unsupported(void)86 int pkeys_unsupported(void)
87 {
88 bool hash_mmu = false;
89 int pkey;
90
91 /* Protection keys are currently supported on Hash MMU only */
92 FAIL_IF(using_hash_mmu(&hash_mmu));
93 SKIP_IF(!hash_mmu);
94
95 /* Check if the system call is supported */
96 pkey = sys_pkey_alloc(0, 0);
97 SKIP_IF(pkey < 0);
98 sys_pkey_free(pkey);
99
100 return 0;
101 }
102
siginfo_pkey(siginfo_t * si)103 int siginfo_pkey(siginfo_t *si)
104 {
105 /*
106 * In older versions of libc, siginfo_t does not have si_pkey as
107 * a member.
108 */
109 #ifdef si_pkey
110 return si->si_pkey;
111 #else
112 return *((int *)(((char *) si) + SI_PKEY_OFFSET));
113 #endif
114 }
115
116 #define pkey_rights(r) ({ \
117 static char buf[4] = "rwx"; \
118 unsigned int amr_bits; \
119 if ((r) & PKEY_DISABLE_EXECUTE) \
120 buf[2] = '-'; \
121 amr_bits = (r) & PKEY_BITS_MASK; \
122 if (amr_bits & PKEY_DISABLE_WRITE) \
123 buf[1] = '-'; \
124 if (amr_bits & PKEY_DISABLE_ACCESS & ~PKEY_DISABLE_WRITE) \
125 buf[0] = '-'; \
126 buf; \
127 })
128
next_pkey_rights(unsigned long rights)129 unsigned long next_pkey_rights(unsigned long rights)
130 {
131 if (rights == PKEY_DISABLE_ACCESS)
132 return PKEY_DISABLE_EXECUTE;
133 else if (rights == (PKEY_DISABLE_ACCESS | PKEY_DISABLE_EXECUTE))
134 return 0;
135
136 if ((rights & PKEY_BITS_MASK) == 0)
137 rights |= PKEY_DISABLE_WRITE;
138 else if ((rights & PKEY_BITS_MASK) == PKEY_DISABLE_WRITE)
139 rights |= PKEY_DISABLE_ACCESS;
140
141 return rights;
142 }
143
144 #endif /* _SELFTESTS_POWERPC_PKEYS_H */
145