1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef _PKEYS_POWERPC_H
4#define _PKEYS_POWERPC_H
5
6#ifndef SYS_mprotect_key
7# define SYS_mprotect_key	386
8#endif
9#ifndef SYS_pkey_alloc
10# define SYS_pkey_alloc		384
11# define SYS_pkey_free		385
12#endif
13#define REG_IP_IDX		PT_NIP
14#define REG_TRAPNO		PT_TRAP
15#define gregs			gp_regs
16#define fpregs			fp_regs
17#define si_pkey_offset		0x20
18
19#undef PKEY_DISABLE_ACCESS
20#define PKEY_DISABLE_ACCESS	0x3  /* disable read and write */
21
22#undef PKEY_DISABLE_WRITE
23#define PKEY_DISABLE_WRITE	0x2
24
25#define NR_PKEYS		32
26#define NR_RESERVED_PKEYS_4K	27 /* pkey-0, pkey-1, exec-only-pkey
27				      and 24 other keys that cannot be
28				      represented in the PTE */
29#define NR_RESERVED_PKEYS_64K_3KEYS	3 /* PowerNV and KVM: pkey-0,
30					     pkey-1 and exec-only key */
31#define NR_RESERVED_PKEYS_64K_4KEYS	4 /* PowerVM: pkey-0, pkey-1,
32					     pkey-31 and exec-only key */
33#define PKEY_BITS_PER_PKEY	2
34#define HPAGE_SIZE		(1UL << 24)
35#define PAGE_SIZE		sysconf(_SC_PAGESIZE)
36
37static inline u32 pkey_bit_position(int pkey)
38{
39	return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
40}
41
42static inline u64 __read_pkey_reg(void)
43{
44	u64 pkey_reg;
45
46	asm volatile("mfspr %0, 0xd" : "=r" (pkey_reg));
47
48	return pkey_reg;
49}
50
51static inline void __write_pkey_reg(u64 pkey_reg)
52{
53	u64 amr = pkey_reg;
54
55	dprintf4("%s() changing %016llx to %016llx\n",
56			 __func__, __read_pkey_reg(), pkey_reg);
57
58	asm volatile("isync; mtspr 0xd, %0; isync"
59		     : : "r" ((unsigned long)(amr)) : "memory");
60
61	dprintf4("%s() pkey register after changing %016llx to %016llx\n",
62			__func__, __read_pkey_reg(), pkey_reg);
63}
64
65static inline int cpu_has_pkeys(void)
66{
67	/* No simple way to determine this */
68	return 1;
69}
70
71static inline bool arch_is_powervm()
72{
73	struct stat buf;
74
75	if ((stat("/sys/firmware/devicetree/base/ibm,partition-name", &buf) == 0) &&
76	    (stat("/sys/firmware/devicetree/base/hmc-managed?", &buf) == 0) &&
77	    (stat("/sys/firmware/devicetree/base/chosen/qemu,graphic-width", &buf) == -1) )
78		return true;
79
80	return false;
81}
82
83static inline int get_arch_reserved_keys(void)
84{
85	if (sysconf(_SC_PAGESIZE) == 4096)
86		return NR_RESERVED_PKEYS_4K;
87	else
88		if (arch_is_powervm())
89			return NR_RESERVED_PKEYS_64K_4KEYS;
90		else
91			return NR_RESERVED_PKEYS_64K_3KEYS;
92}
93
94void expect_fault_on_read_execonly_key(void *p1, int pkey)
95{
96	/*
97	 * powerpc does not allow userspace to change permissions of exec-only
98	 * keys since those keys are not allocated by userspace. The signal
99	 * handler wont be able to reset the permissions, which means the code
100	 * will infinitely continue to segfault here.
101	 */
102	return;
103}
104
105/* 4-byte instructions * 16384 = 64K page */
106#define __page_o_noops() asm(".rept 16384 ; nop; .endr")
107
108void *malloc_pkey_with_mprotect_subpage(long size, int prot, u16 pkey)
109{
110	void *ptr;
111	int ret;
112
113	dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
114			size, prot, pkey);
115	pkey_assert(pkey < NR_PKEYS);
116	ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
117	pkey_assert(ptr != (void *)-1);
118
119	ret = syscall(__NR_subpage_prot, ptr, size, NULL);
120	if (ret) {
121		perror("subpage_perm");
122		return PTR_ERR_ENOTSUP;
123	}
124
125	ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
126	pkey_assert(!ret);
127	record_pkey_malloc(ptr, size, prot);
128
129	dprintf1("%s() for pkey %d @ %p\n", __func__, pkey, ptr);
130	return ptr;
131}
132
133#endif /* _PKEYS_POWERPC_H */
134