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
42inline unsigned long pkeyreg_get(void)
43{
44	return mfspr(SPRN_AMR);
45}
46
47inline void pkeyreg_set(unsigned long amr)
48{
49	set_amr(amr);
50}
51
52void 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
63int 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
68int sys_pkey_alloc(unsigned long flags, unsigned long rights)
69{
70	return syscall(__NR_pkey_alloc, flags, rights);
71}
72
73int sys_pkey_free(int pkey)
74{
75	return syscall(__NR_pkey_free, pkey);
76}
77
78int 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
95int 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
121unsigned 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