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 */