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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#undef PKEY_UNRESTRICTED
28#define PKEY_UNRESTRICTED 0x0
29
30/* Older versions of libc do not define this */
31#ifndef SEGV_PKUERR
32#define SEGV_PKUERR 4
33#endif
34
35#define SI_PKEY_OFFSET 0x20
36
37#define __NR_pkey_mprotect 386
38#define __NR_pkey_alloc 384
39#define __NR_pkey_free 385
40
41#ifndef NT_PPC_PKEY
42#define NT_PPC_PKEY 0x110
43#endif
44
45#define PKEY_BITS_PER_PKEY 2
46#define NR_PKEYS 32
47#define PKEY_BITS_MASK ((1UL << PKEY_BITS_PER_PKEY) - 1)
48
49#define AMR_BITS_PER_PKEY 2
50#define PKEY_REG_BITS (sizeof(u64) * 8)
51#define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey + 1) * AMR_BITS_PER_PKEY))
52
53inline unsigned long pkeyreg_get(void)
54{
55 return mfspr(SPRN_AMR);
56}
57
58inline void pkeyreg_set(unsigned long amr)
59{
60 set_amr(amr);
61}
62
63void pkey_set_rights(int pkey, unsigned long rights)
64{
65 unsigned long amr, shift;
66
67 shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
68 amr = pkeyreg_get();
69 amr &= ~(PKEY_BITS_MASK << shift);
70 amr |= (rights & PKEY_BITS_MASK) << shift;
71 pkeyreg_set(amr);
72}
73
74int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
75{
76 return syscall(__NR_pkey_mprotect, addr, len, prot, pkey);
77}
78
79int sys_pkey_alloc(unsigned long flags, unsigned long rights)
80{
81 return syscall(__NR_pkey_alloc, flags, rights);
82}
83
84int sys_pkey_free(int pkey)
85{
86 return syscall(__NR_pkey_free, pkey);
87}
88
89int pkeys_unsupported(void)
90{
91 bool hash_mmu = false;
92 int pkey;
93
94 /* Protection keys are currently supported on Hash MMU only */
95 FAIL_IF(using_hash_mmu(&hash_mmu));
96 SKIP_IF(!hash_mmu);
97
98 /* Check if the system call is supported */
99 pkey = sys_pkey_alloc(0, PKEY_UNRESTRICTED);
100 SKIP_IF(pkey < 0);
101 sys_pkey_free(pkey);
102
103 return 0;
104}
105
106int siginfo_pkey(siginfo_t *si)
107{
108 /*
109 * In older versions of libc, siginfo_t does not have si_pkey as
110 * a member.
111 */
112#ifdef si_pkey
113 return si->si_pkey;
114#else
115 return *((int *)(((char *) si) + SI_PKEY_OFFSET));
116#endif
117}
118
119#define pkey_rights(r) ({ \
120 static char buf[4] = "rwx"; \
121 unsigned int amr_bits; \
122 if ((r) & PKEY_DISABLE_EXECUTE) \
123 buf[2] = '-'; \
124 amr_bits = (r) & PKEY_BITS_MASK; \
125 if (amr_bits & PKEY_DISABLE_WRITE) \
126 buf[1] = '-'; \
127 if (amr_bits & PKEY_DISABLE_ACCESS & ~PKEY_DISABLE_WRITE) \
128 buf[0] = '-'; \
129 buf; \
130})
131
132unsigned long next_pkey_rights(unsigned long rights)
133{
134 if (rights == PKEY_DISABLE_ACCESS)
135 return PKEY_DISABLE_EXECUTE;
136 else if (rights == (PKEY_DISABLE_ACCESS | PKEY_DISABLE_EXECUTE))
137 return 0;
138
139 if ((rights & PKEY_BITS_MASK) == 0)
140 rights |= PKEY_DISABLE_WRITE;
141 else if ((rights & PKEY_BITS_MASK) == PKEY_DISABLE_WRITE)
142 rights |= PKEY_DISABLE_ACCESS;
143
144 return rights;
145}
146
147#endif /* _SELFTESTS_POWERPC_PKEYS_H */