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Linux kernel mirror (for testing)
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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/* 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
50inline unsigned long pkeyreg_get(void)
51{
52 return mfspr(SPRN_AMR);
53}
54
55inline void pkeyreg_set(unsigned long amr)
56{
57 set_amr(amr);
58}
59
60void 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
71int 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
76int sys_pkey_alloc(unsigned long flags, unsigned long rights)
77{
78 return syscall(__NR_pkey_alloc, flags, rights);
79}
80
81int sys_pkey_free(int pkey)
82{
83 return syscall(__NR_pkey_free, pkey);
84}
85
86int 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
103int 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
129unsigned 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 */