cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pkeys.h (2912B)

      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 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 */