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