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
34 static inline u32 pkey_bit_position(int pkey)
35 {
36 return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
37 }
38
39 static 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
48 static 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
62 static inline int cpu_has_pkeys(void)
63 {
64 /* No simple way to determine this */
65 return 1;
66 }
67
68 static 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
80 static 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
91 void 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
105 void *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
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